JP2019188804A - Electromagnetic wave transmissible metallic sheen article and thin metallic film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electromagnetic wave transmissive metallic luster article and a metal thin film, which have both electromagnetic wave transmissivity and high glitter and can obtain an excellent metallic appearance with suppressed clouding and clouding. A substrate and a metal layer formed on the substrate, the metal layer including a plurality of portions that are discontinuous with respect to each other in at least a portion thereof, and an arithmetic mean surface roughness of the metal layer. An electromagnetic wave permeable metallic luster article having a Ra of 12 nm or less. A metal thin film formed on a substrate, wherein the metal thin film has a thickness of 15 nm to 100 nm and includes a plurality of island-shaped portions that are discontinuous with each other in at least a part of the metal thin film. A metal thin film having an arithmetic average surface roughness Ra of 12 nm or less. [Selection diagram] Figure 1

Description

  The present invention relates to an electromagnetic wave transmissive metallic luster article and a metal thin film.

2. Description of the Related Art Conventionally, members having electromagnetic wave transparency and metallic luster have been suitably used for devices that transmit and receive electromagnetic waves because they have both a high-quality appearance derived from the metallic luster and electromagnetic wave transparency.
For example, there is a need for a metallic luster article that combines both luster and electromagnetic wave transmission, in which a cover member of a millimeter wave radar mounted on the front part of an automobile such as a front grill and an emblem is decorated.

Millimeter wave radar transmits millimeter wave electromagnetic waves (frequency: about 77 GHz, wavelength: about 4 mm) to the front of the car, receives reflected waves from the target, and measures and analyzes the reflected waves. The distance, target direction, and size can be measured.
The measurement result can be used for inter-vehicle measurement, automatic speed adjustment, automatic brake adjustment, and the like.
Since the front part of the automobile in which such a millimeter wave radar is arranged is a so-called automobile face and is a part that gives a large impact to the user, it is preferable to produce a high-class feeling with a metallic glossy front decoration. However, when metal is used for the front part of an automobile, transmission / reception of electromagnetic waves by the millimeter wave radar is substantially impossible or obstructed. Therefore, in order not to impair the design of the automobile without hindering the function of the millimeter wave radar, there is a need for a metallic luster article having both glitter and electromagnetic wave transparency.

  This kind of metallic luster article is not only a millimeter wave radar but also various devices that require communication, for example, automobile door handles with smart keys, in-vehicle communication devices, mobile phones, electronic devices such as personal computers, etc. The application of is expected. Furthermore, in recent years, with the development of IoT technology, application in a wide range of fields such as household appliances such as refrigerators, daily life equipment, etc., which has not been conventionally performed, is expected.

Regarding a metallic luster member, Japanese Patent Application 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 a resin base material, an inorganic base film containing an inorganic compound formed on the resin base material, and glitter and discontinuity formed on the inorganic base film by physical vapor deposition. A metal film made of chromium (Cr) or indium (In) having a structure is included. As an inorganic base film, in Patent Document 1, (a) a thin film of 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.), nitriding Silicon compounds such as silicon (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); oxidation Zircon compounds such as zircon (ZrO); zinc compounds such as zinc sulfide (ZnS), etc. (b) coating films of inorganic paints such as silicon and amorphous TiO _z (and other metal compounds exemplified above) as main components An inorganic coating film is used.

On the other hand, JP 2009-298006 A (Patent Document 2) forms not only chromium (Cr) or indium (In) but also aluminum (Al), silver (Ag), and nickel (Ni) as metal films. An electromagnetic wave transmissive bright resin product that can be used is disclosed.
In JP 2010-5999 A (Patent Document 3), a metal film layer is formed on a base material sheet, and a heat treatment is performed while applying tension to the base material sheet. A method for producing a film decorating sheet is described.

JP 2007-144988 A JP 2009-298006 A JP 2010-5999 A

However, the metal film in the prior art has a problem that the thin film does not have sufficient glitter, and the thick film has white turbidity or cloudiness, resulting in a poor appearance, and an article having both electromagnetic wave permeability and higher glitter is desired. Yes.
The present invention has been made to solve these problems in the prior art, and provides an electromagnetic wave-transmitting metallic luster article and a metal thin film that have both an electromagnetic wave transmitting property and a high luster and have an excellent metal appearance. The purpose is to do.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors usually have a discontinuous structure, for example, a metal layer made of other metals such as aluminum (Al) has a discontinuous structure, and It has been found that an excellent metal appearance that achieves both electromagnetic wave permeability and high luster and suppresses white turbidity and cloudiness can be obtained by using a specific surface roughness, and the present invention has been completed.

One aspect of the present invention includes a base and a metal layer formed on the base,
The metal layer includes a plurality of portions at least partially discontinuous with each other,
The present invention relates to an electromagnetic wave transmissive metallic luster article in which the metal layer has an arithmetic average surface roughness Ra of 12 nm or less.

  In one aspect of the present invention, the electromagnetically transparent metallic glossy article preferably further includes an indium oxide-containing layer between the base and the metal layer.

  In one aspect of the present invention, the electromagnetically transparent metallic glossy article is preferably provided with the indium oxide-containing layer in a continuous state.

In one aspect of the present invention, the electromagnetic wave permeable metallic luster article, the indium oxide-containing layer is indium oxide (In 2 O _3), or indium tin oxide (ITO), or indium zinc oxide (IZO) It is preferable to contain.

  In one aspect of the present invention, the electromagnetically transparent metallic glossy article preferably has a thickness of the indium oxide-containing layer of 1 nm to 1000 nm.

In one aspect of the present invention, in the electromagnetically transparent metallic glossy article, the metal layer preferably has an L ^* value in the range of 0 to 30 measured by an SCE (regular reflection removal method) method.

  1 aspect of this invention WHEREIN: As for the electromagnetic wave permeable metallic luster article, it is preferable that the thickness of the said metal layer is 15-100 nm.

  In one aspect of the present invention, the electromagnetic wave transmissive metallic glossy article has a ratio of the thickness of the metal layer to the thickness of the indium oxide-containing layer (the thickness of the metal layer / the thickness of the indium oxide-containing layer). It is preferable that it is 0.02-100.

  In one embodiment of the present invention, the electromagnetic wave transmissive metallic luster article preferably has a radio wave transmission attenuation of 10 [−dB] or less.

  In one aspect of the present invention, the electromagnetically transparent metallic glossy article preferably has the plurality of portions formed in an island shape.

  In one embodiment of the present invention, the electromagnetic wave transmissive metallic luster article has the metal layer made of aluminum (Al), zinc (Zn), lead (Pb), copper (Cu), silver (Ag), or an alloy thereof. Either is preferable.

  In one aspect of the present invention, in the electromagnetic wave transmissive metallic glossy article, it is preferable that the base is any one of a base film, a resin molded article base, a glass base, or an article to be provided with a metallic luster.

One aspect of the present invention is a metal thin film formed on a substrate,
The metal thin film has a thickness of 15 nm to 100 nm, and includes a plurality of island-shaped portions that are discontinuous with each other at least in part.
It is related with the metal thin film whose arithmetic mean surface roughness Ra of the said metal thin film is 12 nm or less.

  In one embodiment of the present invention, the metal thin film is preferably aluminum (Al), zinc (Zn), lead (Pb), copper (Cu), silver (Ag), or an alloy thereof.

  According to the present invention, it is possible to provide an electromagnetic wave-transmitting metallic glossy article having an excellent metal appearance and a metal thin film that have both electromagnetic wave transparency and high glitter and suppress white turbidity and cloudiness.

FIG. 1 is a schematic cross-sectional view of an electromagnetic wave transmissive metallic luster article according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of an electromagnetic wave transmissive metallic luster article according to an embodiment of the present invention. FIG. 3 is a diagram showing an electron micrograph (SEM image) for explaining the discontinuous structure of the metal layer. FIG. 4 is a view showing electron micrographs of the surfaces of the electromagnetic wave transmissive metallic luster articles of Examples 1 to 3. FIG. 5 is an electron micrograph of the surface of the electromagnetically transparent metallic glossy article of Comparative Examples 1 and 2. FIG. 6 is an electron micrograph of the surface of the electromagnetic wave transmissive metallic luster article of Comparative Examples 3 and 4. FIG. 7 is a view for explaining a method for measuring the thickness of the metal layer of the electromagnetic wave transparent metallic glossy article according to an embodiment of the present invention. FIG. 8 is a diagram showing a transmission electron micrograph (TEM image) of a cross section of a metal layer in one embodiment of the present invention.

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

<1. Basic configuration>
FIG. 1 is a schematic cross-sectional view of an electromagnetic wave transmissive metallic luster article (hereinafter referred to as “metallic luster article”) 1 according to an embodiment of the present invention, and FIG. 3 illustrates the discontinuous structure of the metal layer. The electron micrograph (SEM image) of the surface of the metal layer of a metallic luster article is shown. FIG. 8 shows a transmission electron micrograph (TEM image) of a cross-sectional view of the island-shaped metal layer 12 in one 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 substrate 10. The metal layer 12 includes a plurality of portions 12a. These portions 12a in the metal layer 12 are at least partially discontinuous from each other, in other words, at least partially separated by the gap 12b. Since it is separated by the gap 12b, the sheet resistance is increased and the interaction with the radio wave is reduced, so that the radio wave can be transmitted. Each of these portions 12a may be an aggregate of sputtered particles formed by vapor deposition, sputtering or the like of metal.

  Note that the “discontinuous state” in the present specification means a state in which they are separated from each other by the gap 12b, and as a result, are electrically insulated from each other. By being electrically insulated, the sheet resistance increases, and the desired electromagnetic wave permeability can be obtained. That is, according to the metal layer 12 formed in a discontinuous state, sufficient glitter can be easily obtained, and electromagnetic wave permeability can be secured. A discontinuous form is not specifically limited, For example, an island-like structure, a crack structure, etc. are contained. Here, the “island-like structure” means that metal particles are independent from each other as shown in FIG. 3, and the particles are spread in a state of being slightly separated or partially in contact with each other. It is the structure which becomes.

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

  Although the aspect in which the metal layer 12 becomes discontinuous as described above is not particularly limited, an island structure is preferable from the viewpoint of productivity.

The electromagnetic wave permeability of the metallic luster article 1 can be evaluated by, for example, the amount of radio wave transmission attenuation.
The radio wave transmission attenuation amount in the microwave band (5 GHz) and the radio wave transmission attenuation amount in the frequency band (76 to 80 GHz) of the millimeter wave radar are correlated and show relatively close values. A metallic luster article excellent in electromagnetic wave transmission in the wave band is also excellent in electromagnetic wave transmission in the frequency band of the millimeter wave radar.

The microwave electric field transmission attenuation is preferably 10 [-dB] or less, more preferably 5 [-dB] or less, and still more preferably 2 [-dB] or less. If it is larger than 10 [-dB], there is a problem that 90% or more of radio waves are blocked.
The microwave electric field transmission attenuation amount of the metallic luster article 1 can be measured by the method described in Examples.

The radio wave transmission attenuation amount of the metallic luster article 1 is affected by the material and thickness 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 and thickness of the indium oxide-containing layer 11.

<2. Base>
Examples of the substrate 10 include resins, glasses, and ceramics from the viewpoint of electromagnetic wave transmission.
The substrate 10 may be any one of a substrate film, a resin molded material substrate, a glass substrate, or an article to be provided with a metallic luster.
More specifically, as the base film, for example, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate, polyamide, polyvinyl chloride, polycarbonate (PC), cycloolefin polymer (COP), polystyrene A transparent film made of a homopolymer or copolymer such as polypropylene (PP), polyethylene, polycycloolefin, polyurethane, acrylic (PMMA), or ABS can be used.

  According to these members, the glitter and electromagnetic wave permeability are not affected. However, from the viewpoint of forming the indium oxide-containing layer 11 and the metal layer 12 later, it is preferably one that can withstand high temperatures such as vapor deposition and sputtering. Therefore, among the above materials, for example, polyethylene terephthalate, polyethylene naphthalate, Acrylic, polycarbonate, cycloolefin polymer, ABS, polypropylene and polyurethane are preferred. Of these, polyethylene terephthalate, cycloolefin polymer, polycarbonate, and acrylic are preferable because of a good balance between heat resistance and cost.

The base film may be a single layer film or a laminated film. From the viewpoint of ease of processing, the thickness is preferably about 6 μm to 250 μm, for example. In order to strengthen the adhesion to the indium oxide-containing layer 11 and the metal layer 12, plasma treatment, easy adhesion treatment, or the like may be performed.
When the base 10 is a base film, the metal layer 12 may be provided on at least a part of the base film, may be provided only on 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. In addition to the base film as described above, the base 10 includes a resin molded product base, a glass base, and an article itself to which a metallic luster is to be imparted. Examples of articles that should be provided with a resin-molded base material and metallic luster include, for example, vehicle structural parts, vehicle-mounted products, electronic equipment casings, home appliance casings, structural parts, mechanical parts, and various automobiles. Parts, electronic equipment parts, furniture, household goods such as kitchenware, medical equipment, building material parts, other structural parts and exterior parts.

  The metal layer 12 can be formed on all of these substrates, and may be formed on a part of the surface of the substrate or on the entire surface of the substrate. In this case, the substrate 10 to which the metal layer 12 is to be applied preferably satisfies the same materials and conditions as those of the base film.

<3. Indium oxide-containing layer>
Moreover, the metallic luster article 1 which concerns on one Embodiment may further be provided with the indium oxide containing layer 11 between the base | substrate 10 and the metal layer 12, as FIG. 2 shows. The indium oxide-containing layer 11 may be provided directly on the surface of the substrate 10 or indirectly through a protective film or the like provided on the surface of the substrate 10. The indium oxide-containing layer 11 is preferably provided in a continuous state on the surface of the substrate 10 to be provided with a metallic luster, in other words, without a gap. By providing in a continuous state, the smoothness and corrosion resistance of the indium oxide-containing layer 11, and thus the metal layer 12 and the metallic luster article 1 can be improved, and the indium oxide-containing layer 11 is formed without in-plane variation. It is also easy to do.

  Thus, the indium oxide-containing layer 11 is further provided between the base 10 and the metal layer 12, that is, the indium oxide-containing layer 11 is formed on the base 10, and the metal layer 12 is formed thereon. Is preferable because the metal layer 12 can be easily formed in a discontinuous state. The details of the mechanism are not always clear, but when sputtered particles formed by metal deposition or sputtering form a thin film on the substrate, the surface diffusivity of the particles on the substrate affects the shape of the thin film. It is considered that the discontinuous structure is more easily formed when the temperature of the metal layer is higher, the wettability of the metal layer to the substrate is lower, and the melting point of the material of the metal layer is lower. By providing the indium oxide-containing layer on the substrate, it is considered that the surface diffusibility of the metal particles on the surface is promoted and the metal layer can be easily grown in a discontinuous state.

As the indium oxide-containing layer 11, indium oxide (In ₂ O ₃ ) itself can be used. For example, a metal-containing material such as indium tin oxide (ITO) or indium zinc oxide (IZO) is used. You can also However, ITO or IZO containing the second metal is more preferable in terms of high discharge stability in the sputtering process. By using these indium oxide-containing layers 11, a film in a continuous state can be formed along the surface of the substrate. In this case, a metal layer laminated on the indium oxide-containing layer is For example, it is preferable because an island-like discontinuous structure is easily obtained. Furthermore, as will be described later, in this case, not only chromium (Cr) or indium (In) but also a discontinuous structure is usually difficult to be applied to the metal layer. It becomes easy to include various metals.

The content ratio (content ratio = (SnO ₂ / (In ₂ O ₃ + SnO ₂ )) × 100) which is a mass ratio of tin oxide (SnO ₂ ) contained in ITO is not particularly limited. 0.5 wt% to 30 wt%, more preferably 3 wt% to 10 wt%. The content ratio (content ratio = (ZnO / (In ₂ O ₃ + ZnO)) × 100) which is a mass ratio of zinc oxide (ZnO) contained in IZO is, for example, 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, and still more preferably 20 nm or less, from the viewpoints of sheet resistance, electromagnetic wave permeability, and productivity. On the other hand, in order to facilitate the discontinuous state of the metal layer 12 to be laminated, the thickness is preferably 1 nm or more, and in order to easily facilitate the discontinuous state, it is more preferably 2 nm or more, and 5 nm or more. More preferably.

<4. Metal layer>
The metal layer 12 is formed on the substrate and includes a plurality of portions at least partially discontinuous with each other, and the surface roughness (arithmetic average surface roughness) Ra of the metal layer 12 is 12 nm or less.

When the metal layer 12 is in a continuous state on the substrate, sufficient radiance can be obtained, but the radio wave transmission attenuation amount becomes very large, and therefore electromagnetic wave transmission cannot be ensured.
On the substrate, the metal layer 12 is formed in a discontinuous state, and the surface roughness Ra is set to 12 nm or less, so that both electromagnetic wave permeability and high brilliancy are achieved, and white turbidity, cloudiness, and blueness are suppressed. It is possible to obtain an electromagnetic wave-transmitting metallic luster article having a metallic appearance.

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

The surface roughness Ra of the metal layer 12 is preferably 12 nm or less, more preferably 10 nm or less, and more preferably 7 nm or less in order to exhibit more excellent glitter and to suppress white turbidity, cloudiness, and bluishness. More preferably it is. The lower limit value of the surface roughness Ra of the metal layer 12 is not particularly limited, and is most preferably 0.
The arithmetic average surface roughness Ra of the metal layer 12 can be measured according to JIS B 0601: 1994.

  The surface roughness Ra of the metal layer 12 can be set to the above range by adjusting the average particle diameter of the plurality of portions 12a of the metal layer. By reducing the average particle diameter of the plurality of metal island-shaped portions 12a forming the discontinuous metal layer, the glitter can be improved while maintaining high radio wave transmissivity. This is because the surface roughness Ra can be made the above range by reducing the average particle size of the plurality of metal island portions 12a forming the metal layer, thereby suppressing the diffuse reflection and the visible light region. It was found that specular reflection increases with specular reflection.

Here, the average particle diameter of the plurality of portions 12a means the average value of the equivalent circle diameters of the plurality of portions 12a. The equivalent circle diameter of the portion 12a is the diameter of a perfect circle corresponding to the area of the portion 12a.
In view of the above, the equivalent circle diameter of the metal portion in the island-shaped metal layer 12 is preferably 30 nm or more, more preferably 40 nm or more, and even more preferably 50 nm or more. Moreover, from said viewpoint, 500 nm or less is preferable, 350 nm or less is more preferable, and 200 nm or less is still more preferable.
The distance between the metal portions is not particularly limited, but is preferably 1 nm or more, more preferably 3 nm or more, and still more preferably 5 nm or more from the above viewpoint. Moreover, from said viewpoint, 50 nm or less is preferable, 30 nm or less is more preferable, and 10 nm or less is still more preferable.

  Conventionally, with the increase in the amount of film formation, crystal grains adjacent to each other are mixed together to form a single crystal grain and promote growth. For this reason, as the average particle size increases, the surface roughness Ra of the metal layer becomes rough and changes to a continuous film, so that the radio wave permeability is lowered. Therefore, by reducing the initial crystal grain size, the gap between adjacent crystal grains was successfully reduced. By using this method, the surface roughness Ra of the metal layer can be controlled within a specific range. As a result, diffused light can be suppressed, high reflectance can be obtained, and both high electromagnetic wave transparency and high glitter can be realized. It was.

In the metal layer 12, the L ^* value of the L ^* a ^* b ^* display system measured by the SCE (regular reflected light removal) method is preferably 30 or less, more preferably 20 or less, and 10 or less. More preferably. By setting the L ^* value to 30 or less, it is possible to further suppress white turbidity and cloudiness and to obtain a metal appearance having excellent brightness. It is preferably 0 or more.
L ^* represents lightness, and becomes brighter as the numerical value increases from 0 to 100.

  It is desirable that the metal layer 12 has a relatively low melting point as well as sufficient glitter. This is because the metal layer 12 is preferably formed by thin film growth using sputtering. For this reason, a metal having a melting point of about 1000 ° C. or less is suitable as the metal layer 12. For example, aluminum (Al), zinc (Zn), lead (Pb), copper (Cu), silver (Ag) It is preferable that at least one kind of metal selected from the above and an alloy containing the metal as a main component are included. In particular, Al and alloys thereof are preferable for the reasons such as the luster and stability of the substance and the price. Moreover, when using an aluminum alloy, it is preferable that aluminum content shall be 50 mass% or more.

  The thickness of the metal layer 12 is usually preferably 10 nm or more so as to exhibit sufficient glitter, and is usually preferably 100 nm or less from the viewpoint of productivity. For example, 15 nm to 100 nm is preferable, 15 nm to 80 nm is more preferable, 15 nm to 70 nm is further preferable, 15 nm to 60 nm is still more preferable, 15 nm to 50 nm is particularly preferable, and 15 nm to 40 nm is most preferable. In addition, the thickness of the metal layer 12 can be measured by the method as described in the column of an Example.

For the same reason, the ratio of the thickness of the metal layer to the thickness of the indium oxide-containing layer (the thickness of the metal layer / the thickness of the indium oxide-containing layer) is preferably in the range of 0.1 to 100. A range of 3 to 35 is more preferable.
The metallic luster article of the present embodiment may include other layers in addition to the above-described metal layer and indium oxide-containing layer depending on the application. Other layers include an optical adjustment layer (color adjustment layer) such as a highly refractive material for adjusting the appearance such as color, and a protective layer (abrasion resistance) for improving durability such as moisture resistance and scratch resistance. Property layer), barrier layer (corrosion prevention layer), easy adhesion layer, hard coat layer, antireflection layer, light extraction layer, antiglare layer and the like.

<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 same method can be used when a substrate other than the substrate film is used.

  In forming the metal layer 12 on the substrate 10, for example, a method such as vacuum deposition, for example, sputtering can be used.

  When the indium oxide-containing layer 11 is formed on the substrate 10, the indium oxide-containing layer 11 is formed by vacuum deposition, sputtering, ion plating or the like prior to the formation of the metal layer 12. However, sputtering is preferable because the thickness can be strictly controlled even in a large area.

  In addition, when providing the indium oxide containing layer 11 between the base | substrate 10 and the metal layer 12, it is preferable to make it contact directly between an indium oxide containing layer 11 and the metal layer 12 without interposing another layer.

<6. Metal thin film>
The metal thin film according to the present embodiment is a metal thin film formed on the substrate 10, and the metal thin film has a thickness of 15 nm to 100 nm and is in a plurality of discontinuous states at least partially. Including island-like portions, the metal thin film has a surface roughness Ra of 12 nm or less.
The metal layer 12 described above can be formed to a thickness of 15 nm to 100 nm, and only this can be used as a metal thin film. For example, a metal layer 12 is formed by sputtering on an indium oxide-containing layer 11 laminated on a substrate such as a substrate film to obtain a film. Separately from this, an adhesive is applied onto the substrate to produce a substrate with an adhesive layer. The film and the base material are bonded so that the metal layer 12 and the adhesive layer are in contact with each other, and after sufficiently adhering, the film and the base material are peeled off, whereby the metal layer (metal thin film) 12 existing on the outermost surface of the film. Can be transferred to the outermost surface of the substrate.
As the substrate, the metal layer, and the surface roughness Ra, the above description can be used as it is.

<7. Use of metallic luster articles and metal thin films>
Since the metallic luster article and the metal thin film of the present embodiment have electromagnetic wave permeability, it is preferable to use the metallic luster article and the metal thin film for an apparatus and an article that transmit and receive electromagnetic waves, and parts thereof. For example, use for household goods such as structural parts for vehicles, on-vehicle equipment, housing for electronic equipment, housing for home appliances, structural parts, mechanical parts, various automotive parts, electronic equipment parts, furniture, kitchenware, etc. , 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 boxes, electrical components, engine peripheral components, drive system / gear peripheral components, intake / exhaust system components, cooling system components, and the like.
More specifically, electronic devices and home appliances include refrigerators, washing machines, vacuum cleaners, microwave ovens, air conditioners, lighting equipment, electric water heaters, TVs, clocks, ventilation fans, projectors, speakers, and other home appliances, personal computers, mobile phones Electronic information devices such as smartphones, digital cameras, tablet PCs, portable music players, portable game machines, chargers, and batteries.

Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. Prepare the metallic luster article, the thickness of the metal layer, surface roughness (Ra), the radio wave transmission attenuation (-dB), ^L was measured in the SCE (specular removal method) method * ^a * ^{b * L} in the display system ^* Value and glossiness were evaluated. Note that a base film was used as the substrate 10.
The radio wave transmission attenuation is an evaluation regarding electromagnetic wave transmission. A smaller radio wave transmission attenuation value is preferable.
Details of the evaluation method are as follows.
(1) Film thickness evaluation method First, a square area 3 having a side of 5 cm is appropriately extracted from a metallic glossy article as shown in FIG. A total of five points “a” to “e” obtained by dividing each of these into four equal parts were selected as measurement points.
Next, a cross-sectional image (transmission electron micrograph (TEM image)) as shown in FIG. 8 is measured at each selected measurement location, and five or more metal portions 12a are included from the obtained TEM image. The viewing angle region was extracted.
The total cross-sectional area of the metal layer in the viewing angle region extracted at each of the five measurement positions divided by the lateral width of the viewing angle region is defined as the thickness of the metal layer in each viewing angle region. The average value of the thickness of the metal layer in each viewing angle region was defined as the thickness (nm) of the metal layer.

(2) Arithmetic average surface roughness (Ra)
Arithmetic average surface roughness Ra is in accordance with JIS B 0601: 1994, using AFM MultiMode 8 manufactured by Bruker Japan Co., Ltd., under the following conditions, the arithmetic average surface roughness of the metal layers of the metallic luster articles of Examples and Comparative Examples ( Ra) (nm) was measured.
Measurement mode: Tapping mode Spring constant: 200 N / m
Measurement range: 1μ □
The measured arithmetic average surface roughness (Ra) was evaluated according to the following evaluation criteria.
Over 12 (nm): x (defect)
12 (nm) or less to more than 10 (nm): Δ (somewhat poor)
10 (nm) or less to more than 7 (nm): ○ (good)
7 (nm) or less: ◎ (very good)

(3) Radio wave transmission attenuation The radio wave transmission attenuation at 5 GHz was measured using a spectrum analyzer MS4644B manufactured by Anritsu Co., Ltd. with a sample sandwiched between rectangular waveguide measurement evaluation jigs WR-187. In addition, the radio wave transmission attenuation was evaluated based on the measured values according to the following criteria.
The measured radio wave transmission attenuation was evaluated according to the following evaluation criteria.

(Evaluation criteria for radio wave transmission attenuation)
More than 10 [-dB]: x (defect)
10 [−dB] or less to more than 5 [−dB]: Δ (slightly poor)
5 [-dB] or less to more than 2 [-dB]: ○ (good)
2 [-dB] or less: ◎ (very good)

(4) L ^* a ^* b ^* L ^* value in the display system Using the color difference meter CM-700d manufactured by Konica Minolta Japan, the reflected light of diffused light is measured under the conditions of 400 nm to 700 nm by the SCE (Special Component Exclude) method. The L ^* value in the L ^* a ^* b ^* display system was measured. A pulsed xenon lamp was used as the light source. The measured L ^* value was evaluated according to the following evaluation criteria.

(L ^* value evaluation criteria)
Over 30: x (defect)
30 or less to more than 15: △ (somewhat poor)
15 or less to more than 5: ○ (good)
5 or less: ◎ (very good)

(5) Glossiness The 20 ° glossiness (glossiness) of the metallic luster article was measured according to JIS Z 8741 (1997 edition). Specifically, it measured using PG-IIM (made by Nippon Denshoku Industries Co., Ltd.). The glossiness was measured on the surface on the metal layer side. The glossiness of the metallic luster article was judged according to the following evaluation criteria according to the obtained glossiness value.

(Evaluation criteria for glitter)
Less than 900: x (defect)
900 to less than 1100: Δ (somewhat poor)
1100 to less than 1500: ○ (good)
1500 or more: ◎ (very good)

(6) Comprehensive evaluation In the evaluations (2) to (5), ○ (good) when all items are evaluated as ◯ or better, and △ (somewhat poor) when all items are evaluated as △ or more. A case where even one item is x was evaluated as x (defective).

[Example 1]
A PET film (thickness 50 μm, size 100 mm × 100 mm) manufactured by Kimoto Co. was used as the base film.
First, an ITO layer having a thickness of 50 nm was formed directly on the surface of the base film using DC magnetron sputtering. The temperature of the base film when forming the ITO layer was set to 130 ° C. The content of tin oxide (SnO ₂ ) contained in ITO (content rate = (SnO ₂ / (In ₂ O ₃ + SnO ₂ )) × 100) is 10 wt%.

  Next, an aluminum (Al) layer having a thickness of 35 nm was formed on the ITO layer using AC sputtering (AC: 40 kHz) to obtain a metallic luster article (metal thin film). The obtained aluminum layer was a discontinuous layer. The temperature of the base film when forming the Al layer was set to 130 ° C.

[Example 2]
The film thickness of the aluminum (Al) layer laminated | stacked on the ITO layer in Example 1 was changed into 40 nm, and the metallic luster article (metal thin film) was obtained. Other conditions are the same as in the first embodiment. The obtained aluminum layer was a discontinuous layer.

[Example 3]
The film thickness of the aluminum (Al) layer laminated | stacked on the ITO layer in Example 1 was changed into 30 nm, and the metallic luster article (metal thin film) was obtained. Other conditions are the same as in the first embodiment. The obtained aluminum layer was a discontinuous layer.

[Comparative Example 1]
As the substrate, Corning glass (thickness: 550 μm) was used.
An aluminum (Al) layer having a thickness of 100 nm was formed along the surface of the glass substrate by using an evaporation apparatus EX550 manufactured by ULVAC, Inc. to obtain a metallic luster article (metal thin film). The temperature of the glass substrate when forming the Al layer was set to 25 ° C. The obtained aluminum layer was a continuous layer.

[Comparative Example 2]
The aluminum (Al) layer laminated | stacked on the glass base | substrate in the comparative example 1 was changed into the indium (In) layer (film thickness of 40 nm), and the metallic luster article (metal thin film) was obtained. Other conditions are the same as in Comparative Example 1. The obtained indium layer was a discontinuous layer.

[Comparative Example 3]
The film thickness of the indium (In) layer laminated | stacked on the glass base | substrate in the comparative example 2 was changed into 60 nm, and the metallic luster article (metal thin film) was obtained. Other conditions are the same as in Comparative Example 1. The obtained indium layer was a discontinuous layer.

[Comparative Example 4]
The film thickness of the indium (In) layer laminated | stacked on the glass base | substrate in the comparative example 2 was changed into 135 nm, and the metallic luster article (metal thin film) was obtained. Other conditions are the same as in Comparative Example 1. The obtained indium layer was a continuous layer.

Table 1 below shows the evaluation results of the examples and comparative examples obtained above.

  FIG. 4 is a view showing an electron micrograph (SEM image) of the surface of the metallic glossy article (metal thin film) of Examples 1 to 3 obtained as a result of these treatments, and FIG. FIG. 6 is an electron micrograph (SEM image) of the surface of the metallic luster article (metal thin film), and FIG. 6 is an electron micrograph (SEM image) of the surface of the metallic luster article (metal thin film) of Comparative Examples 3 and 4. FIG. The image sizes in the electron micrographs of FIGS. 4 to 6 are all 1 μm × 1 μm.

As is clear from these figures and Table 1, in Examples 1 to 3, since the aluminum layer includes a plurality of portions 12a formed in a discontinuous state, the radio wave transmission attenuation is 0 at a wavelength of 5 GHz. .1 [-dB] or less, and good results were obtained for electromagnetic wave permeability. Further, since the surface roughness Ra of the metal layer was 7.92 (nm) in Example 1 and 5.16 (nm) in Example 2, good results were also obtained for the L ^* value and the glossiness. It was. As a result, about Example 1 and 2, comprehensive evaluation was set to "(circle)" and the favorable metallic luster article and metal thin film which have both electromagnetic wave permeability and glossiness were obtained.
On the other hand, in the metallic luster articles of Comparative Examples 1 and 4, the metal layer became a continuous layer, and the electromagnetic wave permeability was greatly inferior.
In addition, the metallic luster articles of Comparative Examples 2 and 3 had large surface roughness Ra and L ^* values of the metal layer, low glossiness, low glossiness and poor metal appearance.

  In addition, for metals other than aluminum (Al) used in particular in the above examples, for metals with relatively low melting points such as zinc (Zn), lead (Pb), copper (Cu), silver (Ag), It is considered that a discontinuous structure can be formed by a similar method.

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

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

DESCRIPTION OF SYMBOLS 1 Metal luster article 10 Base | substrate 11 Indium oxide containing layer 12 Metal layer 12a Part 12b Gap

Claims (14)

A substrate and a metal layer formed on the substrate;
The metal layer includes a plurality of portions at least partially discontinuous with each other,
An electromagnetic wave transmissive metallic glossy article, wherein the metal layer has an arithmetic average surface roughness Ra of 12 nm or less.   The electromagnetically transparent metal glossy article according to claim 1, further comprising an indium oxide-containing layer between the base and the metal layer.   The electromagnetic wave transmissive metallic luster article according to claim 2, wherein the indium oxide-containing layer is provided in a continuous state. The electromagnetic wave-transmitting metallic luster according to claim 2 or 3, wherein the indium oxide-containing layer includes any one of indium oxide (In ₂ O ₃ ), indium tin oxide (ITO), or indium zinc oxide (IZO). Goods.   The electromagnetic wave transmissive metallic luster article according to any one of claims 2 to 4, wherein the indium oxide-containing layer has a thickness of 1 nm to 1000 nm. The electromagnetic wave-transmissive metallic glossy article according to any one of claims 1 to 5, wherein the metal layer has an L ^* value measured by an SCE (regular reflection removing method) method in a range of 0 to 30.   The thickness of the said metal layer is 15 nm-100 nm, The electromagnetic wave permeable metallic luster article of any one of Claims 1-6.   The ratio of the thickness of the metal layer to the thickness of the indium oxide-containing layer (the thickness of the metal layer / the thickness of the indium oxide-containing layer) is 0.02 to 100. 2. An electromagnetic wave transparent metallic luster article according to item 1.   The electromagnetic wave transmission metallic luster article according to any one of claims 1 to 8, wherein the radio wave transmission attenuation is 10 [-dB] or less.   The electromagnetic wave transmitting metallic luster article according to any one of claims 1 to 9, wherein the plurality of portions are formed in an island shape.   The metal layer is any one of aluminum (Al), zinc (Zn), lead (Pb), copper (Cu), silver (Ag), or an alloy thereof. The electromagnetically transparent metallic luster article described.   The electromagnetic wave-transmitting metallic glossy article according to any one of claims 1 to 11, wherein the substrate is any one of a base film, a resin molded article base, a glass base, or an article to be provided with metallic luster. . A metal thin film formed on a substrate,
The metal thin film has a thickness of 15 nm to 100 nm, and includes a plurality of island-shaped portions that are discontinuous with each other at least in part.
A metal thin film having an arithmetic average surface roughness Ra of 12 nm or less.   The metal thin film according to claim 13, wherein the metal thin film is any one of aluminum (Al), zinc (Zn), lead (Pb), copper (Cu), silver (Ag), or an alloy thereof.

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