Electromagnetic wave reflection film and tiling method of electromagnetic wave reflection film

Abstract

The present invention provides a transparent and flexible electromagnetic wave reflection film which can be tiled on an existing building.　This electromagnetic wave reflection film is provided with: a conductive layer that reflects electromagnetic waves in a specific frequency band of 1 GHz to 300 GHz inclusive; a first base material layer that supports the conductive layer; an adhesive layer that is provided on the first base material layer side or on the conductive layer side of a laminate which includes the first base material layer and the conductive layer; and a second base material layer that covers the adhesive layer. The thickness of the adhesive layer is 0.02 mm to 1.00 mm inclusive, the shear storage elastic modulus at 23°C is 1 × 102 Pa to 1 × 109 Pa inclusive, and the loss elastic modulus is 1 × 102 Pa to 1 × 108 Pa inclusive.

Description

Electromagnetic wave reflective film and tiling method for electromagnetic wave reflective film

[0001] The present invention relates to an electromagnetic wave reflective film and a method for tiling an electromagnetic wave reflective film.

[0002] Base stations are being deployed in indoor and outdoor spaces to realize a variety of use cases, including automation of manufacturing processes and office work, remote operation, the introduction of AI (artificial intelligence) control and management, and autonomous driving. Indoor and outdoor spaces include factories, plants, office buildings, commercial facilities, medical facilities, event venues, highways, and railway tracks. The fifth-generation mobile communication system (hereinafter referred to as "5G") offers a frequency band below 6 GHz, known as "sub-6," and the 28 GHz band, classified as the millimeter wave band. The next-generation 6G mobile communication standard is expected to expand into the terahertz band. Using these high-frequency bands will expand communication bandwidth, enabling large-volume data transmission with low latency.

[0003] 5G radio waves have a strong tendency to travel in a straight line and are difficult to diffract. On roads, radio waves are blocked by vehicles and structures on the road, and in factories, by machines and product racks on production lines, creating dead zones in various locations. By installing electromagnetic wave reflecting panels in appropriate locations, dead zones can be eliminated. A configuration has been proposed in which electromagnetic wave reflecting devices are placed along at least a portion of a production line (see, for example, Patent Document 1).

[0004] International Publication No. 2021 / 199504

[0005] Metal reflectors made of metal plates such as aluminum and copper are well-known electromagnetic wave reflective panels. Metal reflectors are generally opaque. When installed on roads, factories, office buildings, etc., they can obstruct visibility. Furthermore, installing metal reflectors on office building windows can not only obstruct natural light but also detract from the building's ambiance and aesthetics. To address this issue, transparent electromagnetic wave reflective panels using resin or glass substrates have been considered. However, it is difficult to attach rigid transparent electromagnetic wave reflective panels with a certain thickness to existing structures without gaps. When rigid electromagnetic wave reflective panels are attached to structures with adhesive, air bubbles or air gaps tend to form between the electromagnetic wave reflective panel and the structure, making them difficult to apply to curved surfaces. Furthermore, when a wide dead zone exists, a large-area electromagnetic wave reflective panel is required, but there are limitations to the size of the electromagnetic wave reflective panel.

[0006] An object of the present invention is to provide a transparent and flexible electromagnetic wave reflective film that can be tiled to existing buildings.

[0007] In one aspect of the embodiment, an electromagnetic wave reflective film comprises: a conductive layer that reflects electromagnetic waves in a predetermined frequency band of 1 GHz or more and 300 GHz or less; a first base material layer that supports the conductive layer; an adhesive layer that is provided on the first base material layer side or the conductive layer side of a laminate that includes the first base material layer and the conductive layer; and a second base material layer that covers the adhesive layer, wherein the adhesive layer has a thickness of 0.02 mm or more and 1.00 mm or less and a shear storage modulus at 23°C of 1 x 10 ２ Pa or more, 1×10 ９ Pa or less, loss modulus is 1 x 10 ２ Pa or more, 1×10 ８ Pa or less.

[0008] In another aspect of the embodiment, a method for tiling an electromagnetic wave reflecting film includes peeling off the second base layer of the above-mentioned electromagnetic wave reflecting film, and attaching multiple electromagnetic wave reflecting films to an object using the adhesive layer at intervals that are 0.0% to 10.0% of the length of the side of the electromagnetic wave reflecting film in the tiling direction and that are equal to or less than the wavelength of the electromagnetic waves used.

[0009] This creates a transparent, flexible electromagnetic wave reflective film that can be tiled onto existing buildings.

[0010] Fig. 4 is a schematic diagram showing an application example of an electromagnetic wave reflecting film of an embodiment. Fig. 5 is a schematic diagram showing another application example of an electromagnetic wave reflecting film of an embodiment. Fig. 6 is a schematic diagram showing the layer structure of an electromagnetic wave reflecting film of a first embodiment. Fig. 7 is a schematic diagram showing an application example of the electromagnetic wave reflecting film of Fig. 2 to window glass. Fig. 8 is a schematic diagram showing the layer structure of an electromagnetic wave reflecting film of a second embodiment. Fig. 9 is a schematic diagram showing an application example of the electromagnetic wave reflecting film of Fig. 4 to window glass. Fig. 10 is a diagram showing the reduction of blind zones by an electromagnetic wave reflecting film of an embodiment.

[0011] In an embodiment, a transparent and flexible electromagnetic wave reflective film having a conductive layer that reflects electromagnetic waves in a predetermined frequency band is configured to be tileable on an existing structure. The thickness of the adhesive layer that adheres the laminate including the conductive layer to the existing structure, and the shear storage modulus and loss modulus are set within appropriate ranges, making it possible to tile the electromagnetic wave reflective film on the surface of the existing structure.

[0012] The following describes an electromagnetic wave reflecting film according to an embodiment with reference to the drawings. The embodiments described below are examples for embodying the technical concept of the invention, and do not limit the present invention to the following steps or numerical values. In the drawings, components having the same function may be assigned the same reference numerals to avoid redundant description. Partial substitution or combination between different embodiments or configuration examples is possible. The size, positional relationship, etc. of each component shown in each drawing may be exaggerated to facilitate understanding of the invention. When referring to a positional relationship, "above" or "below" refers to above or below the stacking direction or film formation direction, unless otherwise specified, and is not an absolute direction.

[0013] Fig. 1A is a schematic diagram showing an application example of an electromagnetic wave reflective film 10 of an embodiment. The electromagnetic wave reflective film 10 is applied to a window glass 3 of a window 1 in, for example, a shopping mall or an office building. In the coordinate system of Fig. 1A , the height direction or longitudinal direction of the window glass 3 is the Y direction, the width direction or lateral direction is the X direction, and the thickness direction is the Z direction. The electromagnetic wave reflective film 10 is rectangular or square, with a horizontal length Lx and a vertical length Ly. One or more electromagnetic wave reflective films 10 are tiled depending on the size of the electromagnetic wave reflective film 10 and the size of the window glass 3 supported by the window frame 6.

[0014] The electromagnetic wave reflecting films 10 are tiled with a horizontal spacing Gx and a vertical spacing Gy. The tiling spacing Gx and Gy are selected within a range of 0.0% to 10.0% of the length of the side of the electromagnetic wave reflecting film 10 in the tiling direction and equal to or less than the wavelength of the electromagnetic wave used. In the example of FIG. 1A , the spacing Gx is set to 0.0% to 10.0% of Lx and equal to or less than the wavelength of the electromagnetic wave used, and the spacing Gy is set to 0.0% to 10.0% of Ly and equal to or less than the wavelength of the electromagnetic wave used, but this is not limiting. Depending on the aspect ratio of the electromagnetic wave reflecting film 10, Gx and Gy may be equally spaced and set to 0.0% to 10.0% of the short side or 0.0% to 10.0% of the long side.

[0015] When tiling is performed at 0.0% of the length of one side of the electromagnetic wave reflective film 10, multiple electromagnetic wave reflective films 10 are tiled without any gaps, although the presence of microscopic gaps due to manufacturing errors or cutting errors is acceptable. If the tiling spacing Gx and Gy exceeds 10.0% of one side of the electromagnetic wave reflective film 10, depending on the wavelength of the electromagnetic wave, electromagnetic waves emitted from the base station may be transmitted or absorbed between the films, resulting in a decrease in reflection efficiency. In a preferred configuration example, the electromagnetic wave reflective film 10 has a total light reflectance of 70% or more, preferably 75% or more, and more preferably 80%. Therefore, even if the electromagnetic wave reflective film 10 is tiled to the window glass 3 at intervals of 0.0% to 10.0% of one side, the view and scenery are not obstructed.

[0016] 1B is a schematic diagram showing another application example of the electromagnetic wave reflective film 10. The electromagnetic wave reflective film 10 can be tiled to a structure 2, such as a wall or pillar in a shopping mall or underground shopping mall. By making the entire electromagnetic wave reflective film 10 flexible, the electromagnetic wave reflective film 10 can be tiled to the surface of the structure 2 even if the structure 2 includes a curved surface. The electromagnetic wave reflective film 10 can be tiled at an appropriate position on the surface of the structure 2 depending on the incident direction of the electromagnetic waves and the desired reflection direction. As will be described later, by setting the viscoelasticity of the tiling adhesive layer that attaches the electromagnetic wave reflective film 10 to an object within a predetermined range, the electromagnetic wave reflective film 10 can be adhered to and held on the surface of the structure 2 even if the structure 2 has a certain degree of surface roughness.

[0017] Because the electromagnetic wave reflective film 10 is a transparent, flexible film, it can be presented to the outside without interfering with the display of information such as text, still images, and moving images drawn or displayed on the surface of the structure 2. Even if the base station is not within the line of sight (LOS) of the receiving antenna, the electromagnetic wave reflective film 10 tiled on the surface of the structure 2 can expand the reception area for radio waves in a predetermined frequency band emitted from the base station.

[0018] <First Embodiment> Fig. 2 is a schematic diagram of the layer structure of an electromagnetic wave reflecting film 10 of a first embodiment. The electromagnetic wave reflecting film 10 has a first base material layer 11 and a conductive layer 13 supported on the first base material layer 11. A laminate 15 including the first base material layer 11 and the conductive layer 13 has a tiling adhesive layer 12 on the conductive layer 13 side or on the first base material layer 11 side. In the first embodiment, the adhesive layer 12 is provided on the conductive layer 13 side, covering one surface 132 of the conductive layer 13. A surface 131 of the conductive layer 13 opposite the surface 132 is supported by the first base material layer 11. A second base material layer 14 is provided covering the adhesive layer 12.

[0019] The first base layer 11 is a transparent, flexible dielectric film having a thickness of 1.00 mm or less, preferably 0.70 mm or less, more preferably 0.50 mm or less, and even more preferably 0.10 mm or less. The flexible film is made of a transparent, heat-resistant, dielectric resin material such as polyethylene terephthalate (PET), polycarbonate (PC), cycloolefin polymer (COP), polyimide (PI), or fluororesin.

[0020] The first base layer 11 functions as a support layer for the conductive layer 13, and can also function as a protective layer that protects the surface 131 of the conductive layer 13 depending on the direction of incidence of the electromagnetic waves. For example, when the electromagnetic wave reflective film 10 is attached to a window glass or a structure via the adhesive layer 12 using the second base layer 14 as a release layer, the first base layer 11 can serve as a protective layer that protects one surface 131 of the conductive layer 13. The first base layer 11 is transparent to visible light and also transparent to electromagnetic waves in a predetermined frequency band of 1 GHz or more and 300 GHz or less, and minimizes attenuation of electromagnetic waves in the above frequency band that are incident on the conductive layer 13.

[0021] The conductive layer 13 is formed of a good conductor such as Ag, Cu, Ni, Al, or Pd, or a transparent metal oxide conductor, and may be processed into a periodic pattern, mesh pattern, geometric pattern, or the like. The conductive layer 13 reflects electromagnetic waves in a predetermined frequency band from 1 GHz to 300 GHz. Electromagnetic waves in this range include microwaves, millimeter waves, and submillimeter waves. The conductive layer 13 may be formed as a regular reflecting surface that specularly reflects electromagnetic waves in the above frequency band, or as a metasurface that controls the reflection or diffusion of incident electromagnetic waves. The conductive layer 13 may also have a specular reflecting surface region and a metasurface region.

[0022] When the conductive layer 13 is formed of an indium oxide-based transparent conductive material doped with a metal element such as Sn, Ti, Zn, Zr, Ga, or W, or a metal material with high visible light transmittance such as Ag, the conductive layer 13 may be formed as a solid film on the first substrate layer 11 or as a thin film having a periodic pattern. The conductive layer 13 may also be formed as a mesh pattern of a metal such as SUS, Al, or Cu. When a metal mesh pattern is used, it is desirable to set the aperture ratio of the metal mesh to 70% or more so that the total light transmittance is 70% or more. When the conductive layer 13 is formed of Ag or a transparent conductive material, it can be formed on the first substrate layer 11 by sputtering or vacuum deposition at room temperature. When a metal mesh is used, a pre-fabricated metal mesh may be placed on the first substrate layer 11, and the adhesive layer 12 may be applied to the metal mesh. Alternatively, a metal mesh pattern may be formed on the first substrate layer 11 by sputtering and etching, for example.

[0023] When the conductive layer 13 is formed by sputtering or vacuum deposition, the conductive layer 13 can be formed as a thin film having a thickness of 5 nm to 500 nm. When a metal mesh is used, the thickness of the conductive layer 13 may be several hundred nm to several hundred μm. From the viewpoint of reflection efficiency, the surface resistivity of the conductive layer 13 is preferably 10.0 Ω / □ or less. When a metal mesh is used, the surface resistivity of the conductive layer 13 can be made less than 0.1 Ω / □.

[0024] The adhesive layer 12 is a dielectric adhesive that can be peeled or reworked. Before tiling the electromagnetic wave reflecting film 10, the second substrate layer 14 is adhered to the surface 132 of the conductive layer 13 by the adhesive layer 12. When using the electromagnetic wave reflecting film 10, the second substrate layer 14 is peeled off, and the electromagnetic wave reflecting film 10, including the laminate 15 of the first substrate layer 11 and the conductive layer 13, is tiled to an existing structure using the adhesive layer 12. The adhesive layer 12 may be made of a thermoplastic resin such as vinyl acetate resin, acrylic resin, cellulose resin, or silicone resin. The adhesive layer 12 may be made of a durable and moisture-resistant ethylene-vinyl acetate (EVA) copolymer or cycloolefin polymer (COP). The thickness "t" of the adhesive layer 12 can be appropriately selected between 0.02 mm and 1.00 mm depending on the material of the adhesive layer 12, the thickness and weight of the laminate 15 including the conductive layer 13 and the first substrate layer 11, and the like.

[0025] The second base layer 14 is used as a release layer. Before the electromagnetic wave reflective film 10 is attached to a target structure, the second base layer 14 is attached to the conductive layer 13 via the adhesive layer 12. When the electromagnetic wave reflective film 10 is attached to a window glass or a structure, the second base layer 14 is peeled off, but before peeling off, it functions as a protective layer for the conductive layer 13.

[0026] FIG. 3 is a schematic diagram showing an example of application of the electromagnetic wave reflective film 10 of FIG. 2 to a window glass 3. The electromagnetic wave reflective film 10, from which the second base layer 14 has been peeled off, is attached to the surface of the window glass 3 supported by a window frame 6, by an adhesive layer 12. The electromagnetic wave reflective film 10 is tiled in the YZ plane at a tiling interval Gy. The arithmetic mean roughness (Ra) of the surface of chemically strengthened glass used in buildings and the like is approximately 0.2 to 0.8 μm. The electromagnetic wave reflective film 10 may be attached from the indoor 4 side or from the outdoor 5 side. In places where a small wireless base station is installed indoors 4, such as offices and shopping malls, the electromagnetic wave reflective film 10 may be attached from the indoor 4 side. In this case, electromagnetic waves W radiated from the antenna of the base station installed indoors 4 are reflected by the reflective film 10. ＥＭis reflected toward the indoor 4 by the conductive layer 13 of the electromagnetic wave reflecting film 10, thereby reducing the blind zone of the indoor 4.

[0027] If the window glass 3 and adhesive layer 12 are transparent to electromagnetic waves in the frequency range of 1 GHz to 300 GHz and the conductive layer 13 has a reflecting function for the frequency band for wireless communication used outdoors 5, the conductive layer 13 also functions as a reflective film for electromagnetic waves incident from outdoors 5. In this case, it is also possible to reduce the blind zone of outdoors 5.

[0028] When the electromagnetic wave reflective film 10 is attached from the outdoor 5 side, the first base layer 11 may have impact resistance or weather resistance so as to function as a protective layer. A polycarbonate film, a PET film, a COP film, or the like having a thickness of 0.1 mm or more and 1.0 mm or less may be used as the base layer having a protective function. A hard coat layer for ultraviolet protection and scratch prevention may be provided on both or either one of the surfaces of the first base layer 11.

[0029] The dielectric constants and dielectric loss tangents of the first base layer 11 and the adhesive layer 12 are appropriately selected for the entire laminate so that the electromagnetic wave reflecting film 10 achieves the target reflection characteristics. The dielectric constant of the dielectric portion excluding the conductive layer 13 is, for example, 2.0 or more and 3.0 or less, and the dielectric loss tangent is 0.0001 or more and less than 0.1000. Flexible films with a dielectric constant of less than 2.0 are currently difficult to obtain. If the dielectric constant exceeds 3.0, there is a risk of increased loss, particularly at high frequencies. The same is true for the dielectric loss tangent. Flexible films with a dielectric loss tangent of less than 0.0001 are difficult to obtain, and if the dielectric loss tangent is 0.1000 or more, the loss of electrical energy within the electromagnetic wave reflecting film 10 increases.

[0030] By using a flexible first base layer 11 and optimizing the thickness and viscoelasticity of the adhesive layer 12 according to the thickness or weight of the laminate 15, the second base layer 14 can be peeled off and the electromagnetic wave reflective film 10 can be tiled to an existing building. Tiling the electromagnetic wave reflective film 10 forms a large-area electromagnetic wave reflective surface, making it possible to expand the reception area of ​​radio waves from base stations.

[0031] Second Embodiment Fig. 4 is a schematic diagram of the layer structure of an electromagnetic wave reflecting film 20 of a second embodiment. The electromagnetic wave reflecting film 20 includes a first substrate layer 21 and a conductive layer 23 supported by the first substrate layer 21. A tiling adhesive layer 22 is provided on the conductive layer 23 side or the first substrate layer 21 side of a laminate 25 including the first substrate layer 21 and the conductive layer 23. In the configuration example of Fig. 4, the adhesive layer 22 is provided on the first substrate layer 21 side of the laminate 25. The conductive layer 23 is disposed on one surface 211 of the first substrate layer 21, and the adhesive layer 22 is applied to the other surface 212 of the first substrate 21. The surface of the adhesive layer 22 opposite the first substrate layer 21 is covered with a second substrate layer 24. A third substrate layer 27 is adhered to the surface of the conductive layer 23 opposite the first substrate layer 21 by a second adhesive layer 26.

[0032] The first base layer 21 is a transparent, flexible dielectric film having a thickness of 1.00 mm or less, preferably 0.70 mm or less, more preferably 0.50 mm or less, and even more preferably 0.10 mm or less. As in the first embodiment, the flexible film is made of a transparent, heat-resistant, dielectric resin material such as PET, PC, COP, PI, or fluororesin.

[0033] The first base material layer 21 functions as a support layer for the conductive layer 23, and also as an attachment surface to a window glass or a structure. For example, when the electromagnetic wave reflective film 20 is attached to a window glass or a structure via the adhesive layer 22 using the second base material layer 24 as a release layer, the surface 212 of the first base material layer 21 carrying the adhesive layer 22 becomes the attachment surface to the window glass or a structure.

[0034] The adhesive layer 22 is a dielectric adhesive that can be peeled off or reworked. Before using the electromagnetic wave reflecting film 10, the adhesive layer 22 is covered with a second substrate layer 24. When tiling the electromagnetic wave reflecting film 10, the second substrate layer 24 is peeled off, and the electromagnetic wave reflecting film 20 is adhered and held to an existing structure by the adhesive layer 22. The adhesive layer 22 may be made of a thermoplastic resin, such as a vinyl acetate resin, an acrylic resin, a cellulose resin, or a silicone resin. The adhesive layer 22 may be made of a durable and moisture-resistant ethylene-vinyl acetate (EVA) copolymer or a cycloolefin polymer (COP). The thickness "t" of the adhesive layer 22 may be appropriately selected between 0.02 mm and 1.00 mm depending on the material of the adhesive layer 22 and the thickness and weight of the laminate 25 including the conductive layer 23 and the first substrate layer 21.

[0035] The conductive layer 23 is formed of a good conductor such as Ag, Cu, Ni, Al, or Pd, or a transparent metal oxide conductor, and may be processed into a periodic pattern, mesh pattern, geometric pattern, or the like. The conductive layer 23 reflects electromagnetic waves in a predetermined frequency band from 1 GHz to 300 GHz. Electromagnetic waves in this range include microwaves, millimeter waves, and submillimeter waves. The conductive layer 23 may be formed as a regular reflective surface that specularly reflects electromagnetic waves in the above frequency band, or as a metasurface that controls the reflection or diffusion of incident electromagnetic waves. The material, formation method, surface resistivity, thickness, and the like of the conductive layer 23 are the same as those of the conductive layer 13 of the first embodiment.

[0036] The second adhesive layer 26 is a dielectric adhesive layer capable of adhering the third base material layer 27 to the conductive layer 23, and may be made of a thermoplastic resin such as vinyl acetate resin, acrylic resin, cellulose resin, or silicone resin. Ethylene-vinyl acetate (EVA) copolymer or cycloolefin polymer (COP), which are durable and moisture-resistant, may also be used as the second adhesive layer 26. The thickness of the second adhesive layer 26 may be any thickness that is sufficient to hold the third base material layer 27 on the surface of the conductive layer 23.

[0037] The third base layer 27 is transparent to visible light and also transparent to electromagnetic waves in a predetermined frequency band of 1 GHz to 300 GHz, minimizing attenuation of electromagnetic waves in the above frequency band that are incident on the conductive layer 23. The third base layer 27 functions as a protective layer. A hard coat layer for scratch prevention or ultraviolet protection may be applied to both or either one of the surfaces of the third base layer 27.

[0038] 5 is a schematic diagram showing an example of application of the electromagnetic wave reflecting film 20 of FIG. 4 to a window glass 3. The electromagnetic wave reflecting film 20, from which the second base layer 24 has been peeled off, is attached to the surface of the window glass 3 supported by a window frame 6, by an adhesive layer 22. The electromagnetic wave reflecting film 20 is tiled in the YZ plane at a tiling interval Gy. Since the adhesive layer 22 supports the entire electromagnetic wave reflecting film 20 on the window glass 3, it is desirable that the adhesive layer 22 be thicker or more adhesive than the second adhesive layer 26. The electromagnetic wave reflecting film 20 may be attached from the indoor 4 side or from the outdoor 5 side. When the electromagnetic wave reflecting film 20 is arranged on the indoor 4 side, the electromagnetic waves W incident from the indoor 4 side are reflected by the adhesive layer 22. ＥＭ is reflected toward the indoor 4 by the conductive layer 23 of the electromagnetic wave reflecting film 20, thereby reducing the blind zone of the indoor 4.

[0039] If the window glass 3, adhesive layer 22, and first base layer 21 are transparent to electromagnetic waves in the range of 1 GHz to 300 GHz, and the conductive layer 23 has a reflecting function for the frequency band for wireless communication used outdoors 5, the conductive layer 23 also functions as a reflective film for electromagnetic waves incident from outdoors 5. In this case, the blind zone of outdoors 5 can be reduced.

[0040] When the electromagnetic wave reflective film 20 is attached from the outdoor 5 side, the third base layer 27 may have impact resistance or weather resistance so as to function as a protective layer. A PC film, PET film, COP film, or the like having a thickness of 0.1 mm to 1.0 mm may be used as the base layer having a protective function. A hard coat layer for UV protection and scratch prevention may be provided on both or either one of the surfaces of the third base layer 27.

[0041] The dielectric constants and dielectric loss tangents of the first base layer 21, adhesive layer 22, second adhesive layer 26, and third base layer 27 are appropriately selected for the entire laminate so that the electromagnetic wave reflecting film 20 achieves the target reflection characteristics. As in the first embodiment, the dielectric constant of the dielectric portion excluding the conductive layer 23 is, for example, 2.0 or more and 3.0 or less, and the dielectric loss tangent is 0.0001 or more and less than 0.1000. Flexible films with a dielectric constant of less than 2.0 are currently difficult to obtain. If the dielectric constant exceeds 3.0, there is a risk of increased loss, particularly at high frequencies. The same is true for the dielectric loss tangent. Flexible films with a dielectric loss tangent of less than 0.0001 are difficult to obtain, and if the dielectric loss tangent is 0.1000 or more, the loss of electrical energy within the electromagnetic wave reflecting film 20 increases.

[0042] By using a flexible first base layer 21 and optimizing the thickness and viscoelasticity of the adhesive layer 22 according to the total thickness or weight of the first base layer 21, the conductive layer 23, the second adhesive layer 26, and the third base layer 27, it is possible to peel off the second base layer 24 and tile the electromagnetic wave reflective film 20 to an existing structure. Tiling the electromagnetic wave reflective film 20 forms a large-area electromagnetic wave reflective surface, making it possible to expand the reception area of ​​radio waves from a base station.

[0043] Fig. 6 is a diagram showing the reduction of blind zones by the electromagnetic wave reflective film 10 or 20 of the embodiment. The electromagnetic wave reflective films 10 or 20 are tiled at predetermined intervals on an existing building 7. For simplicity of illustration, two electromagnetic wave reflective films 10 or 20 are arranged in the X direction in Fig. 6, but three or more electromagnetic wave reflective films 10 or 20 may be tiled in the X direction as needed. Similarly, an appropriate number of electromagnetic wave reflective films 10 or 20 can be tiled in the Y direction depending on the height of the building 7 and the required reflection area or space.

[0044] Within the communication area of ​​base station 30, there is an obstacle 40 that interferes with the radio waves from base station 30. Obstacle 40 may be a steel bookshelf, rack, or partition with heat insulation. When viewed from the transmitting antenna of base station 30, the area behind obstacle 40 is a dead zone 41 where the reception strength is 30 dB or more lower than the surrounding area. By tiling electromagnetic wave reflective film 10 or 20 over a desired area on the surface of existing building 7, the reception strength in dead zone 41 can be improved and the communication area of ​​base station 30 can be expanded.

[0045] <Characteristic Evaluation> Below, a sample of an electromagnetic wave reflective film is prepared, and the total light transmittance and return loss of the sample, as well as the change in reception intensity in the blind zone 41 before and after tiling, are measured. In order to stably attach and maintain the electromagnetic wave reflective film 10 or 20 (hereinafter collectively referred to as the "electromagnetic wave reflective film 10") to an existing building 7 with a certain degree of surface roughness, an adhesive layer with appropriate viscoelasticity is required. The change in stress that occurs in the tiling adhesive layer when the electromagnetic wave reflective film 10 is subjected to periodic stress or deformation is called dynamic viscoelasticity. Dynamic viscoelasticity includes a storage modulus and a loss modulus. The storage modulus is the component of energy generated in the adhesive layer by external force and strain that is stored internally, while the loss modulus is the component that diffuses to the outside. Of the storage modulus, the force acting in a plane parallel to the attachment surface is the shear storage modulus.

[0046] In order to affix the electromagnetic wave reflecting film 10 to the surface of the existing building 7 and to hold it in a stable state, it is necessary for the adhesive layer to reliably penetrate into the interface between the electromagnetic wave reflecting film 10 and the existing building 7 and to adhere to the building with a predetermined force. There is a trade-off between the ease with which the adhesive layer penetrates into the interface (fluidity) and its adhesion to the surface of the building 7. Therefore, the thickness and viscoelasticity of the adhesive layer, i.e., the shear storage modulus and loss modulus, of each sample are changed, and the changes in total light transmittance, return loss, and reception intensity in the blind zone 41 are measured.

[0047] The total light transmittance is measured using an ultraviolet-visible-infrared spectrophotometer manufactured by Shimadzu Corporation. The return loss of the sample is measured using a method conforming to JIS R1679. Specifically, the return loss is measured when a plane wave of a predetermined frequency band is incident at an incident angle of 0°. Receiving points are set every 1.0 m in the X and Z directions within the XZ plane of the blind zone 41, and the average of the measurements at all receiving points is taken as the receiving intensity. The receiving points are omnidirectional receiving antennas installed at a height of 1.0 m. The base station 30 is equipped with an omnidirectional transmitting antenna, the height of which is 3.0 m, and the maximum gain is 5 dBi or more and 30 dBi or less. The base station 30 emits radio waves in the 4.7 GHz band with a vertical beam width of 25° and a horizontal beam width of 25°. A sample having a total light transmittance of 70% or more and capable of improving the receiving intensity in the blind zone 41 by 10 dB or more is used as the electromagnetic wave reflective film of the embodiment.

[0048] Example 1 Example 1 is Example 1. An electromagnetic wave reflecting film 20 of the second embodiment is produced as a sample. A PET film measuring 0.5 m in length, 0.5 m in width, and 0.15 mm in thickness is used as the first base layer 21. A transparent conductive film having a thickness of 0.36 mm is formed on the surface of this PET film to form the conductive layer 23. A general-purpose silicone adhesive having a thickness of 0.025 mm is applied to the surface of the conductive layer 23 as the second adhesive layer 26, and a PET film having a thickness of 0.10 mm is adhered to the surface, to form the third base layer 27. An adhesive layer 22 having a thickness (t) of 0.02 mm is applied to the surface of the first base layer 21 opposite the conductive layer 23, and a PET film having a thickness of 0.1 mm is adhered to the surface, to form the second base layer 24. The adhesive layer 22 is a removable adhesive having a shear storage modulus of 1×10 at 23° C. ９ Pa, loss modulus 1 × 10 ８ Pa. The total light transmittance of this sample is 85.3%, and the return loss is −0.15 dB.

[0049] The second base layer 24 of the electromagnetic wave reflective film 20 is peeled off, and two sheets of the electromagnetic wave reflective film 20 are attached to a glass wall material using a rubber roller, one vertically and one horizontally, so that the average tiling interval is 2.3 mm. The arithmetic mean roughness (Ra) of the glass wall material, measured using a method in accordance with JIS B0601:2013, is 0.8 μm, and the return loss of the wall material, measured using a method in accordance with JIS R 1679, is −10.0 dB. A 4.7 GHz electromagnetic wave was emitted from a transmitting antenna of a base station 30 with a maximum gain of 25 dBi, and the reception intensity was measured in a blind zone 41 before and after tiling with the electromagnetic wave reflective film 20. An improvement of +10 dB in the blind zone 41 was confirmed.

[0050] Example 2 Example 2 is Example 2. An electromagnetic wave reflecting film 20 of the second embodiment is produced as a sample. A PET film measuring 0.5 m in length, 0.5 m in width, and 0.15 mm in thickness is used as the first base layer 21. A transparent conductive film having a thickness of 0.36 mm is formed on the surface of this PET film to form the conductive layer 23. A general-purpose silicone adhesive having a thickness of 0.025 mm is applied to the surface of the conductive layer 23 as the second adhesive layer 26, and a PET film having a thickness of 0.10 mm is adhered to the surface, to form the third base layer 27. Up to this point, the configuration is the same as in Example 1. An adhesive layer 22 having a thickness (t) of 1.00 mm is applied to the surface of the first base layer 21 opposite the conductive layer 23, and a PET film having a thickness of 0.1 mm is adhered to the surface, to form the second base layer 24. The adhesive layer 22 is a re-peelable adhesive having a shear storage modulus of 1×10 at 23°C. ２ Pa, loss modulus 1×10 ２ The viscoelasticity of the adhesive layer 22 in Example 2 is smaller than that of the adhesive layer 22 used in Example 1, but the adhesive layer 22 is formed to be correspondingly thicker. The total light transmittance of the sample in Example 2 is 82.3%, and the return loss is −0.25 dB.

[0051] The second base layer 24 of the electromagnetic wave reflective film 20 is peeled off, and two sheets of the electromagnetic wave reflective film 20 are attached to a concrete wall material using a rubber roller, one vertically and one horizontally, so that the average tiling interval is 0.0 mm. The arithmetic mean roughness (Ra) of the concrete wall material measured using a method in accordance with JIS B0601:2013 is 4.2 mm, and the return loss measured using a method in accordance with JIS R 1679 is -30.0 dB. Electromagnetic waves of 4.7 GHz are emitted from a transmitting antenna of a base station 30 with a maximum gain of 25 dBi, and the reception intensity is measured in a blind zone 41 before and after tiling with the electromagnetic wave reflective film 20. An improvement of +15 dB in the blind zone 41 is confirmed.

[0052] Example 3 Example 3 is Example 3. An electromagnetic wave reflecting film 20 of the second embodiment is produced as a sample. A PET film measuring 2.0 m in length, 3.0 m in width, and 0.15 mm in thickness is used as the first base layer 21. A transparent conductive film having a thickness of 0.36 mm is formed on the surface of this PET film to form the conductive layer 23. A general-purpose silicone adhesive having a thickness of 0.025 mm is applied to the surface of the conductive layer 23 as the second adhesive layer 26, and a PET film having a thickness of 0.10 mm is adhered to the surface, forming the third base layer 27. Except for the length and width of the sample, the configuration is the same as that of Example 1. An adhesive layer 22 having a thickness (t) of 0.50 mm is applied to the surface of the first base layer 21 opposite the conductive layer 23, and a PET film having a thickness of 0.1 mm is adhered to the surface, forming the second base layer 24. The adhesive layer 22 is a re-peelable adhesive having a shear storage modulus of 1×10 at 23°C. ９ Pa, loss modulus 1 × 10 ９ The viscoelasticity of the adhesive layer 22 in Example 2 is close to that of the adhesive layer 22 used in Example 1. The thickness of the adhesive layer 22 is made thicker than the thickness of the general-purpose silicone-based second adhesive layer 26 by the amount of increase in the vertical and horizontal sizes of the sample. The total light transmittance of the sample in Example 3 is 80.3%, and the return loss is −0.25 dB.

[0053] The second base layer 24 of the electromagnetic wave reflective film 20 was peeled off, and two sheets were attached vertically and two horizontally to a wallpapered wall material using a rubber roller so that the average tiling interval was 30.0 mm. The arithmetic mean roughness (Ra) of the wallpapered wall material measured using a method in accordance with JIS B0601:2013 was 1.0 mm, and the return loss measured using a method in accordance with JIS R 1679 was -20.0 dB. A 4.7 GHz electromagnetic wave was emitted from a transmitting antenna of a base station 30 with a maximum gain of 25 dBi, and the reception intensity was measured in a blind zone 41 before and after tiling with the electromagnetic wave reflective film 20. An improvement of +25 dB in the blind zone 41 was confirmed.

[0054] Example 4 Example 4 is Example 4. As a sample, an electromagnetic wave reflecting film 10 of the first embodiment is produced. A PET film measuring 0.5 m in length, 0.5 m in width, and 0.15 mm in thickness is used as the first base layer 11. A transparent conductive film having a thickness of 0.36 mm is formed on the surface of this PET film to form the conductive layer 13. An adhesive layer 12 having a thickness of 0.025 mm is applied to the surface of the conductive layer 13, and a PET film having a thickness of 0.10 mm is adhered to the surface to form the second base layer 14. The adhesive layer 12 is a removable adhesive having a shear storage modulus of 1×10 at 23° C. ８ Pa, loss modulus 1×10 ７ Pa. The total light transmittance of this sample is 91.3%, and the return loss is −0.15 dB.

[0055] The second base layer 14 of the electromagnetic wave reflective film 10 was peeled off, and two sheets of the electromagnetic wave reflective film 10 were attached to a glass wall material using a rubber roller, one vertically and one horizontally, so that the average tiling interval was 2.3 mm. The arithmetic mean roughness (Ra) of the glass wall material, measured using a method conforming to JIS B0601:2013, was 0.8 μm, and the return loss of the wall material, measured using a method conforming to JIS R 1679, was −10.0 dB. A 4.7 GHz electromagnetic wave was emitted from a transmitting antenna of a base station 30 with a maximum gain of 25 dBi, and the reception intensity was measured in a blind zone 41 before and after tiling with the electromagnetic wave reflective film 10. An improvement of +10 dB in the blind zone 41 was confirmed.

[0056] Example 5 Example 5 is Comparative Example 1. An electromagnetic wave reflecting film 20 of the second embodiment is produced as a sample. A PET film measuring 0.5 m in length, 0.5 m in width, and 0.15 mm in thickness is used as the first base layer 21. A transparent conductive film having a thickness of 0.36 mm is formed on the surface of this PET film to form the conductive layer 23. Up to this point, the configuration is the same as that of Example 1. A general-purpose silicone adhesive having a thickness of 0.050 mm is applied to the surface of the conductive layer 23 as the second adhesive layer 26, and a PET film having a thickness of 0.10 mm is adhered to the second adhesive layer 26 to form the third base layer 27. An adhesive layer 22 having a thickness (t) of 0.015 mm is applied to the surface of the first base layer 21 opposite the conductive layer 23, and a PET film having a thickness of 0.1 mm is adhered to the second base layer 24. The adhesive layer 22 is a removable adhesive having a shear storage modulus of 1×10 at 23°C. １ Pa, loss modulus 1×10 １ The viscoelasticity of the adhesive layer 22 in Example 4 was lower than that of the adhesive layer 22 in Example 1, and the thickness of the adhesive layer 22 was thinner than that of the second adhesive layer 26. The total light transmittance of the sample in Example 4 was 80.3%. Because the shear storage modulus of the adhesive layer 22 was low, the second base material layer 24 could not be properly bonded to the first base material layer 21 by the adhesive layer 22, resulting in distortion and the return loss was −1.25 dB.

[0057] The second base layer 24 of the electromagnetic wave reflective film 20 was peeled off, and two sheets of the electromagnetic wave reflective film 20 were attached vertically and horizontally using a rubber roller so that the average tiling interval was 30.0 mm to a wall material with wallpaper. However, numerous air bubbles were generated, and the affixing was not successful. The arithmetic mean roughness (Ra) of the wall material with wallpaper, measured using a method in accordance with JIS B0601:2013, was 1.0 mm, and the return loss, measured using a method in accordance with JIS R 1679, was -20.0 dB. Electromagnetic waves of 4.7 GHz were emitted from a transmitting antenna of a base station 30 with a maximum gain of 25 dBi, and the reception intensity in the blind zone 41 was measured before and after tiling with the electromagnetic wave reflective film 20. No improvement in reception intensity was confirmed. This is thought to be because the adhesive layer 22 had low viscoelasticity and was insufficient in thickness, making it unable to hold the electromagnetic wave reflective film 20 to the wall material, resulting in high absorption on the exposed surface of the wall material.

[0058] Example 6 Example 6 is Comparative Example 2. An electromagnetic wave reflecting film 20 of the second embodiment is produced as a sample. A PET film measuring 0.5 m in length, 0.5 m in width, and 0.15 mm in thickness is used as the first base layer 21. A transparent conductive film having a thickness of 0.36 mm is formed on the surface of this PET film to form the conductive layer 23. Up to this point, the configuration is the same as that of Example 1. A general-purpose silicone adhesive having a thickness of 0.050 mm is applied to the surface of the conductive layer 23 as the second adhesive layer 26, and a PET film having a thickness of 0.10 mm is adhered to the second adhesive layer 26 to form the third base layer 27. An adhesive layer 22 having a thickness (t) of 0.025 mm is applied to the surface of the first base layer 21 opposite the conductive layer 23, and a PET film having a thickness of 0.1 mm is adhered to the second base layer 24. The adhesive layer 22 is a removable adhesive having a shear storage modulus of 1×10 at 23°C. ２ Pa, loss modulus 1×10 ２ The viscoelasticity of the adhesive layer 22 of Example 5 is lower than that of the adhesive layer 22 of Example 1, and the thickness of the adhesive layer 22 is thinner than that of the second adhesive layer 26. The sample of Example 5 has a total light transmittance of 72.3%, a sufficient shear storage modulus of the adhesive, and a return loss of −0.23 dB.

[0059] The second base layer 24 of the electromagnetic wave reflective film 20 was peeled off, and two sheets of the electromagnetic wave reflective film were attached vertically and horizontally to a wall material with wallpaper using a rubber roller so that the average tiling interval was 55.0 mm. Unlike the sample of Example 4, the electromagnetic wave reflective film 20 was successfully attached and maintained on the wall material. The arithmetic mean roughness (Ra) of the wallpapered wall material measured using a method conforming to JIS B0601:2013 was 1.0 mm, and the return loss measured using a method conforming to JIS R 1679 was -20.0 dB. 28 GHz electromagnetic waves were emitted from a transmitting antenna of a base station 30 with a maximum gain of 25 dBi, and the reception intensity in the blind zone 41 was measured before and after tiling with the electromagnetic wave reflective film 20. No improvement in reception intensity was confirmed. This is thought to be because the tiling interval was large, approximately the wavelength of the electromagnetic waves, and electromagnetic waves were absorbed on the exposed surface of the wall material not covered by the electromagnetic wave reflective film 20.

[0060] Example 7 Example 7 is Comparative Example 3. An electromagnetic wave reflecting film 10 of the first embodiment is produced as a sample. A PET film measuring 0.5 m in length, 0.5 m in width, and 0.15 mm in thickness is used as the first base layer 11. A transparent conductive film having a thickness of 0.36 mm is formed on the surface of this PET film to form the conductive layer 13. An adhesive layer 12 having a thickness of 0.015 mm is provided to cover the conductive layer 13, and a PET film having a thickness of 0.10 mm is adhered to the adhesive layer 12 as the second base layer 14. The adhesive layer 12 is a removable adhesive having a shear storage modulus of 1×10 at 23° C. １ Pa, loss modulus 1×10 １ The total light transmittance of the sample of Example 7 was 91.3%. Because the shear storage modulus of the adhesive layer 12 was low, the second base layer 14 could not be properly bonded to the conductive layer 13, causing distortion and the like, and the return loss was −1.57 dB.

[0061] The second base layer 14 of the electromagnetic wave reflective film 10 was peeled off, and two sheets of the electromagnetic wave reflective film 10 were attached to a wall material with wallpaper, one vertically and one horizontally, using a rubber roller so that the average tiling interval was 30.0 mm. However, numerous air bubbles were generated, and the attachment was not successful. The arithmetic mean roughness (Ra) of the wallpaper-attached wall material, measured using a method in accordance with JIS B0601:2013, was 1.0 mm, and the return loss, measured using a method in accordance with JIS R 1679, was -20.0 dB. Electromagnetic waves of 4.7 GHz were emitted from a transmitting antenna of a base station 30 with a maximum gain of 25 dBi, and the reception intensity in the blind zone 41 was measured before and after tiling with the electromagnetic wave reflective film 10. No improvement in reception intensity was confirmed. This is thought to be because the adhesive layer 12 had low viscoelasticity and was insufficient in thickness, making it impossible to hold the electromagnetic wave reflective film 10 to the wall material, resulting in significant absorption on the exposed surface of the wall material.

[0062] The results of Examples 1 to 7 lead to the following: (1) When the thickness of the adhesive layer 12 or 22 is set to 0.02 mm or more and 1.00 mm, the shear storage modulus at 23° C. is 1×10 ２ Pa or more, 1×10 ９ Pa or less, loss modulus is 1 x 10 ２ Pa or more, 1×10８ (2) The shear storage modulus at 23°C of the adhesive layer for tiling the electromagnetic wave reflecting film can be selected from the range of 1 x 10 Pa or less. ２ Pa or more, 1×10 ９ Pa or less, loss modulus is 1 × 10 ２ Pa or more, 1×10 ８ By setting the thickness of the adhesive layer 22 in the range of 0.05 Pa or less, the film can be attached to a surface having an arithmetic mean roughness (Ra) of 5.0 mm or less, as measured by a method conforming to JIS B0601:2013. (3) When attaching the electromagnetic wave reflective film 20 of the second embodiment to an existing structure, it is desirable that the thickness of the adhesive layer 22 be greater than the thickness of the second adhesive layer 26 that adheres the third base layer 27, or that the shear storage modulus and loss modulus be greater than those of the second adhesive layer 26. (4) When tiling rectangular or square electromagnetic wave reflective films 10 or 20, it is desirable that the tiling spacing be 0.0% or more and 10.0% or less of the side of the electromagnetic wave reflective film in the tiling direction, and be smaller than the wavelength of the electromagnetic waves used.

[0063] The tiling method using the electromagnetic wave reflecting film of the embodiment involves peeling off the second base layer of the above-mentioned electromagnetic wave reflecting film, and attaching multiple electromagnetic wave reflecting films to an object using the above-mentioned adhesive layer at a tiling interval of 0.0% to 10.0% of the side of the electromagnetic wave reflecting film in the tiling direction and equal to or less than the wavelength of the electromagnetic waves used.

[0064] In a preferred embodiment, a plurality of electromagnetic wave reflective films are tiled at the above-mentioned intervals on a surface having an arithmetic mean roughness (Ra) of 5.0 mm or less as measured by a method in accordance with JIS B0601:2013.

[0065] The above-described configuration realizes a transparent electromagnetic wave reflective film with excellent reflection properties. Both the electromagnetic wave reflective film 10 of the first embodiment and the electromagnetic wave reflective film 20 of the second embodiment can be manufactured using a roll-to-roll method and can be cut to the desired size from a roll. The length of a single electromagnetic wave reflective film 10 or 20 in the horizontal or width direction is, for example, 0.3 m or more and 3.0 m or less, and the length in the vertical or roll flow direction is, for example, 0.3 m or more and 10.0 m. By tiling such an electromagnetic wave reflective film 10 or 20 at the above-described tiling interval, a large-area electromagnetic wave reflective surface is formed.

[0066] The above disclosure includes the following configuration: (Item 1) A laminate including a conductive layer that reflects electromagnetic waves in a predetermined frequency band of 1 GHz or more and 300 GHz or less, a first base material layer that supports the conductive layer, an adhesive layer that is provided on the first base material layer side or the conductive layer side of a laminate including the first base material layer and the conductive layer, and a second base material layer that covers the adhesive layer, wherein the adhesive layer has a thickness of 0.02 mm or more and 1.00 mm or less and a shear storage modulus at 23°C of 1 x 10 ２ Pa or more, 1×10 ９ Pa or less, loss modulus is 1 x 10 ２ Pa or more, 1×10 ８An electromagnetic wave reflective film having a surface resistivity of 10.0 Ω / □ or less. (Item 2) The electromagnetic wave reflective film according to Item 1, wherein the adhesive layer is disposed on the conductive layer side of the laminate, and the second base material layer covers the adhesive layer on the conductive layer side. (Item 3) The electromagnetic wave reflective film according to Item 1, wherein the adhesive layer is disposed on the first base material layer side of the laminate, and the second base material layer covers the adhesive layer on the side opposite the conductive layer. (Item 4) The electromagnetic wave reflective film according to Item 3, further comprising: a second adhesive layer covering the surface of the conductive layer; and a third base material layer covering the second adhesive layer. (Item 5) The electromagnetic wave reflective film according to Item 4, wherein the adhesive layer is thicker than the second adhesive layer or has greater viscoelasticity than the second adhesive layer. (Item 6) The electromagnetic wave reflective film according to any one of Items 1 to 5, wherein the conductive layer has a surface resistivity of 10.0 Ω / □ or less. (Item 7) The electromagnetic wave reflective film according to any one of Items 1 to 6, wherein a hard coat layer is applied to both or either one of the surfaces of the first base material layer. (Item 8) The electromagnetic wave reflective film according to any one of Items 4 to 7, wherein a hard coat is applied to both or either one of the surfaces of the third base material layer. (Item 9) A method for tiling an electromagnetic wave reflective film, comprising peeling off the second base material layer of the electromagnetic wave reflective film according to any one of Items 1 to 8, and attaching a plurality of the electromagnetic wave reflective films to an object via the adhesive layer at intervals of 0.0% to 10.0% of a side in the tiling direction of the electromagnetic wave reflective film and at intervals equal to or less than the wavelength of the electromagnetic waves used. (Item 10) The method for tiling an electromagnetic wave reflective film according to Item 9, wherein a plurality of the electromagnetic wave reflective films are tiled on a surface of the object having an arithmetic mean roughness (Ra) of 5.0 mm or less, measured according to a method in accordance with JIS B0601:2013.

[0067] This international application claims priority based on Japanese Patent Application No. 2023-190976, filed on November 8, 2023, the entire contents of which are incorporated herein by reference.

[0068] 2 Structure 3 Window glass 7 Existing building 10, 20 Electromagnetic wave reflective film 11, 21 First base material layer 12, 22 Adhesive layer 13, 23 Conductive layer 14, 24 Second base material layer 15, 25 Laminate 26 Second adhesive layer 27 Third base material layer 30 Base station 40 Obstacle 41 Dead zone Gx, Gy Interval

Claims

1. A laminate comprising: a conductive layer that reflects electromagnetic waves in a predetermined frequency band of 1 GHz or more and 300 GHz or less; a first base material layer that supports the conductive layer; an adhesive layer provided on the first base material layer side or the conductive layer side of a laminate including the first base material layer and the conductive layer; and a second base material layer that covers the adhesive layer, wherein the adhesive layer has a thickness of 0.02 mm or more and 1.00 mm or less and has a shear storage modulus of 1×10 at 23° C. ２ Pa or more, 1×10 ９ Pa or less, loss modulus is 1×10 ２ Pa or more, 1×10 ８ An electromagnetic wave reflective film having a reflectance of 0.1 Pa or less.

2. The electromagnetic wave reflecting film according to claim 1, wherein the adhesive layer is disposed on the conductive layer side of the laminate, and the second base layer covers the adhesive layer on the conductive layer side.

3. The electromagnetic wave reflecting film according to claim 1, wherein the adhesive layer is disposed on the side of the first base material layer of the laminate, and the second base material layer covers the adhesive layer on the side opposite the conductive layer.

4. The electromagnetic wave reflective film according to claim 3, further comprising: a second adhesive layer covering the surface of the conductive layer; and a third base material layer covering the second adhesive layer.

5. The electromagnetic wave reflecting film according to claim 4, wherein the adhesive layer is thicker than the second adhesive layer or has a greater viscoelasticity than the second adhesive layer.

6. The electromagnetic wave reflective film according to claim 1, wherein the surface resistivity of the conductive layer is 10.0 Ω / □ or less.

7. The electromagnetic wave reflective film according to claim 1, wherein a hard coat layer is applied to both or either one of the surfaces of the first base layer.

8. The electromagnetic wave reflective film according to claim 4, wherein a hard coat is applied to both or either one of the surfaces of the third base layer.

9. A method for tiling an electromagnetic wave reflecting film comprising peeling off the second base layer of the electromagnetic wave reflecting film described in claim 1, and attaching a plurality of the electromagnetic wave reflecting films to an object using the adhesive layer at intervals of 0.0% to 10.0% of the side of the electromagnetic wave reflecting film in the tiling direction and at intervals equal to or less than the wavelength of the electromagnetic waves used.

10. The electromagnetic wave reflective film tiling method according to claim 9, comprising tiling a plurality of the electromagnetic wave reflective films onto a surface of the object having an arithmetic mean roughness (Ra) of 5.0 mm or less as measured by a method conforming to JIS B0601:2013.