Electromagnetic wave shielding film

Abstract

Provided is an electromagnetic wave shielding film in which the surface of a protective layer has high whiteness when the electromagnetic wave shielding film is viewed from the protective layer side. This electromagnetic wave shielding film is obtained by laminating a white protective layer, a silver layer, and an adhesive layer in that order, the electromagnetic wave shielding film being characterized in that the white protective layer and the silver layer are adjacent, the white protective layer contains 5 wt% or more of a white pigment, and the L* value in the L*a*b* color system of the surface of the white protective layer when the electromagnetic wave shielding film is viewed from the white protective layer side is 90.0 or higher.

Description

Electromagnetic wave shielding film

[0001] This invention relates to an electromagnetic wave shielding film.

[0002] Flexible printed circuit boards (PCBs) are widely used in electronic devices such as mobile phones, video cameras, and laptop computers, which are rapidly becoming smaller and more sophisticated, to integrate circuits into complex mechanisms. Furthermore, their excellent flexibility allows them to be used to connect movable parts, such as printer heads, to control units. Electromagnetic shielding is essential in these electronic devices, and flexible printed circuit boards used within these devices are increasingly incorporating electromagnetic shielding measures.

[0003] As a measure against electromagnetic waves, an electromagnetic shielding film is known that includes a protective layer made of insulating resin and a shielding layer made of a conductive material such as metal foil. Electromagnetic shielding can be implemented by attaching the electromagnetic shielding film to a flexible printed circuit board.

[0004] The protective layer of an electromagnetic wave shielding film may be colored depending on the purpose. For example, Patent Document 1 discloses an electromagnetic wave shielding film with a white protective layer for aesthetic reasons. Specifically, Patent Document 1 discloses a resin composition for the protective layer of an electromagnetic wave shielding film, wherein the resin composition comprises an amorphous polyester resin, a curing agent, and a white pigment, the amorphous polyester resin having a number average molecular weight Mn of less than 20,000 and a glass transition temperature Tg of 40°C or higher, and the curing agent being at least one selected from the group consisting of blocked isocyanate, trimethylolpropane adduct of hexanediisocyanate, and isocyanurate adduct of cyclohexanediisocyanate.

[0005] International Publication No. 2019 / 188983

[0006] In the electromagnetic shielding film described in Patent Document 1, although the protective layer is white, the color of the underlying layer (shielding layer and adhesive layer) has an effect, resulting in a problem where the surface color of the protective layer is not sufficiently white (low reflectivity and low whiteness) when the electromagnetic shielding film is viewed from the protective layer side. In other words, there was a problem where the whiteness was low due to the influence of the color of the underlying layer.

[0007] One possible solution to this problem is to increase the thickness of the protective layer. However, this would increase the overall thickness of the electromagnetic shielding film, making it difficult to place the electromagnetic shielding film in electronic devices.

[0008] This invention was made to solve the above problems, and the object of this invention is to provide an electromagnetic wave shielding film in which the surface of the protective layer has a high degree of whiteness when viewed from the protective layer side.

[0009] The electromagnetic wave shielding film of the present invention is an electromagnetic wave shielding film in which a white protective layer, a silver layer, and an adhesive layer are laminated in order, wherein the white protective layer and the silver layer are adjacent to each other, the white protective layer contains 5 wt% or more of white pigment, and the surface L of the white protective layer when the electromagnetic wave shielding film is viewed from the white protective layer side. ＊ a ＊ b ＊ L in color systems ＊ It is characterized by having a value of 90.0 or higher.

[0010] In the electromagnetic wave shielding film of the present invention, the silver layer functions as a shielding layer.

[0011] In the electromagnetic shielding film of the present invention, the white protective layer and the silver layer are adjacent to each other. The silver layer, arranged in this manner, can improve the whiteness of the white protective layer when the electromagnetic shielding film of the present invention is viewed from the white protective layer side. In this specification, "whiteness" refers to whether or not the appearance of the color of the white protective layer changes due to the influence of the color of the underlying layer. "High whiteness" means that the color of the white protective layer is less affected by the color of the underlying layer, and the white protective layer is more likely to appear as its original white color. "Low whiteness" means that the color of the white protective layer is more easily affected by the color of the underlying layer, and the white protective layer is more likely to appear as a color different from its original white due to the influence of the color of the underlying layer.

[0012] In the electromagnetic shielding film of the present invention, the white protective layer contains 5 wt% or more of white pigment. Therefore, the whiteness of the white protective layer is sufficiently high when the electromagnetic shielding film of the present invention is viewed from the white protective layer side. If the amount of white pigment contained in the white protective layer is less than 5 wt%, the white protective layer will not be sufficiently white, and the whiteness of the white protective layer will be low when the electromagnetic shielding film of the present invention is viewed from the white protective layer side.

[0013] In the electromagnetic wave shielding film of the present invention, the surface L of the white protective layer when the electromagnetic wave shielding film is viewed from the white protective layer side. ＊ a ＊ b ＊ L in color systems ＊ The value is 90.0 or higher. Therefore, the electromagnetic wave shielding film of the present invention has high aesthetic appeal.

[0014] In the electromagnetic shielding film of the present invention, the thickness of the white protective layer is preferably 3 to 15 μm. When the thickness of the white protective layer is within this range, the entire electromagnetic shielding film can be made thinner. Furthermore, the whiteness of the white protective layer can be sufficiently high when viewed from the white protective layer side of the electromagnetic shielding film of the present invention. If the thickness of the white protective layer is less than 3 μm, the white protective layer becomes too thin and easily damaged, making it difficult to adequately protect the silver layer and adhesive layer. If the thickness of the white protective layer exceeds 15 μm, the entire electromagnetic shielding film tends to become thicker.

[0015] In the electromagnetic shielding film of the present invention, the white pigment is preferably at least one selected from the group consisting of titanium dioxide, zinc oxide, sodium hydroxide, silica, barium sulfate, talc, mica, glass flakes, boron nitride (BN), calcium carbonate, aluminum hydroxide, titanate, barium sulfate, alumina, kaolin, clay, titanium dioxide, zinc oxide, zinc sulfide, lead titanate, zircon oxide, antimony oxide, and magnesium oxide. These white pigments can suitably impart whiteness to the white protective layer.

[0016] In the electromagnetic wave shielding film of the present invention, the thickness of the silver layer is preferably 0.05 μm or more. By making the thickness of the silver layer 0.05 μm or more, the color of the underlying layer is less likely to affect the whiteness of the surface of the white protective layer when the electromagnetic wave shielding film is viewed from the white protective layer side. In addition, the shielding characteristics of the silver layer are sufficiently enhanced.

[0017] In the electromagnetic shielding film of the present invention, it is preferable that the adhesive layer is a conductive adhesive layer. When the adhesive layer is a conductive adhesive layer, the adhesive layer itself can function as a shielding layer. Furthermore, the electromagnetic shielding film of the present invention is placed on a printed circuit board, and in this case, by bringing the ground circuit of the printed circuit board into contact with the conductive adhesive layer, the silver layer, which is the shielding layer, can be electrically brought into contact with the ground circuit of the printed circuit board. In this case, the shielding characteristics of the silver layer are improved.

[0018] In the electromagnetic shielding film of the present invention, it is preferable that the 60° gloss of the white protective layer, when viewed from the side of the white protective layer, is 5.0 or less. Such an electromagnetic shielding film has good aesthetics.

[0019] According to the present invention, it is possible to provide an electromagnetic wave shielding film in which the surface of the protective layer has a high degree of whiteness when viewed from the protective layer side.

[0020] FIG. 1 is a cross-sectional view schematically showing an example of the electromagnetic wave shielding film of the present invention. FIG. 2 is a cross-sectional view schematically showing an example of a shield printed wiring board provided with the electromagnetic wave shielding film of the present invention.

[0021] Hereinafter, the electromagnetic wave shielding film of the present invention will be specifically described. However, the present invention is not limited to the following embodiments, and can be modified and applied as appropriate without departing from the scope of the gist of the present invention.

[0022] FIG. 1 is a cross-sectional view schematically showing an example of the electromagnetic wave shielding film of the present invention. As shown in FIG. 1, the electromagnetic wave shielding film 10 has a white protective layer 20, a silver layer 30, and an adhesive layer 40 laminated in this order. In the electromagnetic wave shielding film 10, the silver layer 30 functions as a shielding layer.

[0023] In the electromagnetic wave shielding film 10, the white protective layer 20 and the silver layer 30 are adjacent to each other. The silver layer 30 arranged in this manner can improve the whiteness of the white protective layer 20 when the electromagnetic wave shielding film 10 is viewed from the white protective layer 20 side.

[0024] The white protective layer 20 contains 5 wt% or more of a white pigment. The content of the white pigment contained in the white protective layer 20 is preferably 10 to 60 wt%, and more preferably 20 to 55 wt%. When the content of the white pigment is within the above range, the whiteness of the white protective layer 20 becomes sufficiently high when the electromagnetic wave shielding film 10 is viewed from the white protective layer 20 side. When the content of the white pigment contained in the white protective layer is less than 5 wt%, the white protective layer does not become sufficiently white, and the whiteness of the white protective layer becomes low when the electromagnetic wave shielding film of the present invention is viewed from the white protective layer side.

[0025] L of the surface of the white protective layer 20, when the electromagnetic wave shielding film 10 is viewed from the white protective layer 20 side, ＊ a ＊ b ＊ L in the color system ＊ value is 90.0 or more. The L ＊The value is preferably 92.0 or higher, more preferably 93.0 or higher, and even more preferably 93.5 to 100. L on the surface of the white protective layer 20 ＊ a ＊ b ＊ L in color systems ＊ When the value falls within the above range, the aesthetic appeal of the electromagnetic wave shielding film 10 is enhanced.

[0026] In this specification, L ＊ The values ​​refer to those measured in accordance with JIS Z 8781-4 (2013).

[0027] In the electromagnetic wave shielding film 10, it is preferable that the 60° gloss of the white protective layer 20, when viewed from the side of the electromagnetic wave shielding film 10, is 5.0 or less, and more preferably between 3.0 and 5.0. Such an electromagnetic wave shielding film has good aesthetics.

[0028] In this specification, "60° gloss" refers to the value measured using a BYK Gardner Micro-Gloss (portable gloss meter).

[0029] The preferred configurations of each component of the electromagnetic wave shielding film of the present invention are described below.

[0030] (White protective layer) In the electromagnetic shielding film of the present invention, the thickness of the white protective layer is preferably 3 to 15 μm, and more preferably 5 to 15 μm. When the thickness of the white protective layer is within the above range, the entire electromagnetic shielding film can be made thinner. In addition, the whiteness of the white protective layer can be made sufficiently high when the electromagnetic shielding film of the present invention is viewed from the white protective layer side. If the thickness of the white protective layer is less than 3 μm, the white protective layer is too thin and easily damaged, making it difficult to adequately protect the silver layer and adhesive layer. If the thickness of the white protective layer exceeds 15 μm, the entire electromagnetic shielding film tends to become thicker.

[0031] The white protective layer is preferably composed of a resin material, has insulating properties, and satisfies predetermined mechanical strength, chemical resistance, and heat resistance.

[0032] The resin material is not particularly limited as long as it has sufficient insulating properties, and for example, a thermoplastic resin composition, a thermosetting resin composition, an active energy ray-curable composition, or the like can be used.

[0033] The thermoplastic resin composition is not particularly limited, and for example, a styrene-based resin composition, a vinyl acetate-based resin composition, a polyester-based resin composition, a polyethylene-based resin composition, a polypropylene-based resin composition, an imide-based resin composition, an acrylic resin composition, or the like can be used. The thermosetting resin composition is not particularly limited, and for example, a phenol-based resin composition, an epoxy-based resin composition, a urethane-based resin composition, a melamine-based resin composition, an alkyd-based resin composition, or the like can be used. The active energy ray-curable composition is not particularly limited, and for example, a polymerizable compound having at least two (meth)acryloyloxy groups in a molecule, or the like can be used. These compositions may be used alone singly, or two or more of them may be used in combination.

[0034] In the electromagnetic wave shielding film of the present invention, the white pigment contained in the white protective layer is selected from the group consisting of titanium oxide, zinc oxide, sodium hydroxide, silica, barium sulfate, talc, mica, mica, glass flakes, boron nitride (BN), calcium carbonate, aluminum hydroxide, titanate (such as potassium titanate), barium sulfate, alumina, kaolin, clay, titanium oxide, zinc oxide, zinc sulfide, lead titanate, zirconium oxide, antimony oxide and magnesium oxide. It is preferable that the white pigment is at least one selected from the above group. Among these, titanium oxide is more preferable. These white pigments can suitably impart whiteness to the white protective layer.

[0035] In the electromagnetic wave shielding film of the present invention, the average particle diameter of the white pigment is preferably 10 μm or less, and more preferably 0.1 to 5 μm. When the average particle diameter of the white pigment exceeds 10 μm, color spots are likely to occur. Further, when the average particle diameter of the white pigment is less than 0.1 μm, the particles tend to aggregate with each other, which easily causes poor dispersion and is prone to color spots. In this specification, the average particle diameter of the white pigment refers to the particle diameter of the number-average average particle diameter D50 (median diameter) measured by a laser diffraction / scattering method.

[0036] The white protective layer may optionally contain a curing accelerator, a tackifier, an antioxidant, a pigment, a dye, a plasticizer, an ultraviolet absorber, an antifoaming agent, a leveling agent, a filler, a flame retardant, a viscosity modifier, an anti-blocking agent, and the like.

[0037] (Silver Layer) In the electromagnetic wave shielding film of the present invention, the thickness of the silver layer is preferably 0.05 μm or more, and more preferably 0.05 to 2.0 μm. By setting the thickness of the silver layer to 0.05 μm or more, the color of the underlying layer is less likely to affect the whiteness of the surface of the white protective layer when the electromagnetic wave shielding film is viewed from the white protective layer side. In addition, the shielding property of the silver layer becomes sufficiently high. When the thickness of the silver layer is less than 0.05 μm, the aesthetic property tends to decrease due to the influence of the color of the underlying layer.

[0038] In the electromagnetic wave shielding film of the present invention, the silver layer may be a rolled silver foil, a silver plating layer, or a silver vapor deposition layer.

[0039] In the electromagnetic wave shielding film of the present invention, another shielding layer may be laminated between the silver layer and the adhesive layer within a range that does not affect the whiteness of the surface of the white protective layer when the electromagnetic wave shielding film of the present invention is viewed from the white protective layer side. Examples of such a shielding layer include a gold layer, a copper layer, an aluminum layer, a nickel layer, a tin layer, a palladium layer, a chromium layer, a titanium layer, a zinc layer, and the like.

[0040] (Adhesive layer) In the electromagnetic wave shielding film of the present invention, the adhesive layer may be composed of any material that has adhesive properties, but may be composed of thermoplastic resin compositions such as styrene resin compositions, vinyl acetate resin compositions, polyester resin compositions, polyethylene resin compositions, polypropylene resin compositions, imide resin compositions, amide resin compositions, and acrylic resin compositions, or thermosetting resin compositions such as phenol resin compositions, epoxy resin compositions, urethane resin compositions, melamine resin compositions, and alkyd resin compositions. The adhesive layer may contain only one of these materials, or it may contain two or more.

[0041] In the electromagnetic shielding film of the present invention, the thickness of the adhesive layer is not particularly limited, but it is preferably 0.5 to 30.0 μm. If the thickness of the adhesive layer is less than 0.5 μm, it becomes difficult to obtain good adhesion. If the thickness of the adhesive layer exceeds 30.0 μm, the entire electromagnetic shielding film becomes thick and difficult to handle.

[0042] In the electromagnetic shielding film of the present invention, the adhesive layer is preferably a conductive adhesive layer. When the adhesive layer is a conductive adhesive layer, the adhesive layer itself can function as a shielding layer. Furthermore, the electromagnetic shielding film of the present invention is placed on a printed circuit board, and in this case, by bringing the ground circuit of the printed circuit board into contact with the conductive adhesive layer, the silver layer, which is the shielding layer, can be electrically brought into contact with the ground circuit of the printed circuit board. In this case, the shielding characteristics of the silver layer are improved.

[0043] If the adhesive layer is a conductive adhesive layer, the adhesive layer will contain a conductive filler. The conductive filler is not particularly limited and may include silver powder, copper powder, nickel powder, solder powder, aluminum powder, silver-plated copper powder, polymer microparticles, glass beads, and other particles coated with metal.

[0044] The shape of the conductive filler is not particularly limited, but can be appropriately selected from spherical, flattened, flake-shaped, dendritic, rod-shaped, fibrous, and the like.

[0045] The average particle size of the conductive filler is preferably 3.0 to 15 μm, more preferably 5.0 to 11 μm, and even more preferably 5.0 to 8.0 μm.

[0046] The conductive filler content is preferably 3 to 50% by weight, more preferably 3 to 39% by weight, and even more preferably 3 to 30% by weight. If the proportion of conductive filler is less than 3% by weight, conductivity will be difficult to achieve. If the proportion of conductive filler exceeds 50% by weight, the proportion of resin in the adhesive layer becomes relatively small, and the adhesive strength of the adhesive layer tends to decrease. Also, the conductive fillers tend to come into contact with each other (making it easier for current to flow in the planar direction), so when the electromagnetic shielding film is placed on a printed circuit board, electrical properties such as transmission characteristics tend to decrease. When the proportion of conductive filler is 3 to 39% by weight, anisotropic conductivity can be imparted to the adhesive layer. In this case, when the electromagnetic shielding film is placed on a printed circuit board, electrical properties such as transmission characteristics tend to decrease less.

[0047] The adhesive layer may contain, as needed, curing accelerators, tackifiers, antioxidants, pigments, dyes, plasticizers, UV absorbers, defoamers, leveling agents, fillers, flame retardants, viscosity modifiers, etc.

[0048] Next, a shielded printed circuit board using the electromagnetic shielding film of the present invention will be described. The shielded printed circuit board described below will be described in the case where the adhesive layer of the electromagnetic shielding film is a conductive adhesive layer.

[0049] Figure 2 is a schematic cross-sectional view showing an example of a shielded printed circuit board equipped with the electromagnetic wave shielding film of the present invention. The shielded printed circuit board 1 shown in Figure 2 includes a printed circuit board 50 and an electromagnetic wave shielding film 10.

[0050] The printed circuit board 50 comprises a base film 51, a printed circuit 52 arranged on the base film 51, and a coverlay 53 arranged to cover the printed circuit 52. The printed circuit 52 includes a ground circuit 52a. The coverlay 53 also has an opening 53a that exposes the ground circuit 52a.

[0051] In the shielded printed circuit board 1, the adhesive layer 40 is positioned so as to be in contact with the coverlay 53. The adhesive layer 40 fills the opening 53a and is in contact with the ground circuit 52a. If the adhesive layer 40 is a conductive adhesive layer, the ground circuit 52a and the silver layer 30 are electrically connected. This improves the shielding characteristics of the electromagnetic shielding film 10.

[0052] In the printed circuit board 50, it is preferable that both the base film 51 and the coverlay 53 are made of engineering plastic. Examples of such resins include polypropylene, crosslinked polyethylene, polyester, polybenzimidazole, polyimide, polyimideamide, polyetherimide, and polyphenylene sulfide (PPS).

[0053] In the printed circuit board 50, the printed circuit 52 can be made of ordinary circuit materials such as copper.

[0054] Furthermore, the base film 51 and the printed circuit 52 may be bonded together with an adhesive, or they may be joined together without using an adhesive, similar to so-called adhesive-free copper-clad laminates. Also, the coverlay 53 may be made by bonding multiple flexible insulating films together with an adhesive, or it may be formed by a series of methods such as coating, drying, exposure, development, and heat treatment of a photosensitive insulating resin.

[0055] Conventional methods can be used to attach the electromagnetic shielding film 10 to the printed circuit board 50. For example, it is preferable to place the electromagnetic shielding film 10 on the printed circuit board 50 so that the adhesive layer 40 of the electromagnetic shielding film 10 is in contact with the coverlay 53 of the printed circuit board 50, and then heat-press it at a temperature of 150 to 200°C, a pressure of 2 to 5 MPa, and a time of 1 to 60 minutes.

[0056] Up to this point, the shielded printed circuit board 1 has been described in the case where the adhesive layer 40 is conductive and there is an opening 53a in the coverlay 53 of the printed circuit board 50. However, in the electromagnetic wave shielding film of the present invention, the adhesive layer does not need to be conductive. Also, in this case, there does not need to be an opening formed in the coverlay of the printed circuit board.

[0057] This specification describes the following inventions:

[0058] (1) This disclosure relates to an electromagnetic wave shielding film in which a white protective layer, a silver layer, and an adhesive layer are laminated in order, wherein the white protective layer and the silver layer are adjacent, the white protective layer contains 5 wt% or more of white pigment, and the surface of the white protective layer, when the electromagnetic wave shielding film is viewed from the white protective layer side, is L ＊ a ＊ b ＊ L in color systems ＊ This electromagnetic wave shielding film is characterized by having a value of 90.0 or higher.

[0059] Disclosure (2) is an electromagnetic wave shielding film according to Disclosure (1), wherein the thickness of the white protective layer is 3 to 15 μm.

[0060] Disclosure (3) is an electromagnetic wave shielding film according to Disclosure (1) or (2), wherein the white pigment is at least one selected from the group consisting of titanium dioxide, zinc oxide, sodium hydroxide, silica, barium sulfate, talc, mica, glass flakes, boron nitride (BN), calcium carbonate, aluminum hydroxide, titanate, barium sulfate, alumina, kaolin, clay, titanium dioxide, zinc oxide, zinc sulfide, lead titanate, zircon oxide, antimony oxide, and magnesium oxide.

[0061] Disclosure (4) is an electromagnetic wave shielding film according to any of Disclosures (1) to (3), wherein the thickness of the silver layer is 0.05 μm or more.

[0062] Disclosure (5) is an electromagnetic wave shielding film according to any one of Disclosures (1) to (4), wherein the adhesive layer is a conductive adhesive layer.

[0063] Disclosure (6) is an electromagnetic wave shielding film according to any one of Disclosures (1) to (5), wherein the 60° gloss of the white protective layer, as viewed from the side of the white protective layer, is 5.0 or less.

[0064] The following are examples illustrating the present invention in more detail, but the present invention is not limited to these examples.

[0065] (Example 1) A white protective layer composition was prepared by adding titanium dioxide to a polyester resin in a weight ratio of 5 wt% and mixing the mixture.

[0066] Next, a white protective layer composition was applied to the transfer film, and the film was heated in an electric oven at 130°C for 3 minutes to produce a white protective layer with a thickness of 8 μm.

[0067] Next, a silver vapor deposition layer with a thickness of 0.1 μm was applied on top of the white protective layer.

[0068] Next, a conductive adhesive composition was prepared by mixing copper particles with an average particle size of 5 μm with an adhesive resin (epoxy resin). The conductive adhesive composition was formulated to contain 20 wt% copper particles.

[0069] Next, a conductive adhesive composition was applied onto the silver layer to form an adhesive layer with a thickness of 5 μm. This adhesive layer is an anisotropic conductive adhesive layer.

[0070] The electromagnetic shielding film according to Example 1 was manufactured through the above process.

[0071] Using an F2 light source as the light source, a portable integrating sphere spectrophotometer (X-Rite, Ci64) was used to measure the L of the surface of the white protective layer of the electromagnetic wave shielding film according to Example 1, as viewed from the white protective layer side. ＊ When the value was measured, it was found to be 96.9.

[0072] When the 60° gloss of the surface of the white protective layer of the electromagnetic wave shielding film according to Example 1 was viewed from the white protective layer side, the value was measured using a BYK Gardner Micro-Gloss (portable gloss meter), and the value was 4.9.

[0073] Examples 2 to 26 and Comparative Examples 1 to 21 were manufactured in the same manner as in Example 1, except that the thickness of the white protective layer, the content of the white pigment, and the type and thickness of the metal layer were changed, as shown in Tables 1 to 5. Furthermore, the L of the surface of the white protective layer was measured for each example and comparative example, as viewed from the white protective layer side. ＊ The values ​​and 60° gloss were measured. The results are shown in Tables 1 to 5.

[0074]

[0075]

[0076]

[0077]

[0078]

[0079] The electromagnetic wave shielding film according to each embodiment is L ＊ Since the value is 90.0 or higher and the 60° gloss level is 5.0 or lower, it was found to have excellent aesthetic properties.

[0080] 1 Shielded printed circuit board 10 Electromagnetic shielding film 20 White protective layer 30 Silver layer 40 Adhesive layer 50 Printed circuit board 51 Base film 52 Printed circuit 52a Ground circuit 53 Coverlay 53a Opening

Claims

1. An electromagnetic wave shielding film comprising a white protective layer, a silver layer, and an adhesive layer laminated in order, wherein the white protective layer and the silver layer are adjacent to each other, the white protective layer contains 5 wt% or more of white pigment, and the surface L of the white protective layer when the electromagnetic wave shielding film is viewed from the white protective layer side. ＊ a ＊ b ＊ L in color systems ＊ An electromagnetic wave shielding film characterized by having a value of 90.0 or higher.

2. The electromagnetic wave shielding film according to claim 1, wherein the thickness of the white protective layer is 3 to 15 μm.

3. The electromagnetic wave shielding film according to claim 1 or 2, wherein the white pigment is at least one selected from the group consisting of titanium dioxide, zinc oxide, sodium hydroxide, silica, barium sulfate, talc, mica, glass flakes, boron nitride (BN), calcium carbonate, aluminum hydroxide, titanate, barium sulfate, alumina, kaolin, clay, titanium dioxide, zinc oxide, zinc sulfide, lead titanate, zircon oxide, antimony oxide, and magnesium oxide.

4. The electromagnetic wave shielding film according to any one of claims 1 to 3, wherein the thickness of the silver layer is 0.05 μm or more.

5. The electromagnetic wave shielding film according to any one of claims 1 to 4, wherein the adhesive layer is a conductive adhesive layer.

6. The electromagnetic wave shielding film according to any one of claims 1 to 5, wherein the 60° gloss of the white protective layer, when viewed from the side of the white protective layer, is 5.0 or less.

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