Electromagnetic wave shielding film

Abstract

To provide a method of manufacturing an electromagnetic wave shield film capable of efficiently forming a slit of an adhesive layer.SOLUTION: In the adhesive layer forming step, a release film is used, a plurality of protrusions having a shape corresponding to the slit are formed on a surface side of the release film, a plurality of recesses corresponding to a shape of the plurality of adhesive portions are formed between the plurality of protrusions, and the plurality of adhesive portions are formed by an adhesive composition filled in the plurality of recesses.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to an electromagnetic wave shielding film. [Background technology]

[0002] Conventionally, electromagnetic wave shielding films have been used to provide a shield against electromagnetic waves that can cause noise as an EMC countermeasure in electronic devices. Electromagnetic wave shielding films typically include an adhesive layer used for adhesion to an adherend and a shielding layer such as a metal foil laminated on the adhesive layer. Additionally, electromagnetic wave shielding films are also known in which the adhesive layer contains a conductive filler and is provided with a shielding function.

[0003] An example of an adherend for an electromagnetic wave shielding film is a printed circuit board, which typically includes a base film made of a polyimide resin, a circuit pattern formed on the base film, and a coverlay that protects the circuit pattern.

[0004] When an electromagnetic wave shielding film is bonded to a printed circuit board, a process of thermocompression bonding is performed in a state in which the electromagnetic wave shielding film is superimposed on the printed circuit board. Furthermore, components may be mounted on the printed circuit board to which the electromagnetic wave shielding film is bonded using a reflow process. The heat treatment in these processes generates gas from the adhesive layer of the electromagnetic wave shielding film, the base film of the printed circuit board, etc., and it is believed that this gas causes delamination between the adhesive layer and the shielding layer and peeling of the adhesive layer from the printed circuit board. Therefore, Patent Document 1 proposes forming slits in the adhesive layer to allow gas to escape.

[0005] Patent Document 1 describes a method for forming slits, in which an adhesive composition is applied to copper foil that will serve as a shielding layer and dried to laminate an adhesive layer before slit formation on the copper foil, and then a laser beam is irradiated onto the adhesive layer to form slits. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2021-174948 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the method of forming slits one by one by irradiating a laser beam has the problem of lacking efficiency. For example, in continuous production using roll-to-roll processes, it is desirable to be able to form slits in a certain area simultaneously.

[0008] In view of the above circumstances, an object of the present invention is to provide a method for producing an electromagnetic wave shielding film that can efficiently form slits in an adhesive layer. [Means for solving the problem]

[0009] The method for producing an electromagnetic wave shielding film according to the present invention is as follows. [1] A method for producing an electromagnetic wave shielding film comprising an adhesive layer having an adhesive surface to be adhered to an adherend, the adhesive layer having a plurality of adhesive portions separated to form slits, the method comprising: An adhesive layer forming step is provided, In the adhesive layer forming step, a release film is used, and a plurality of protrusions having shapes corresponding to the slits are formed on a surface side of the release film, and a plurality of recesses corresponding to shapes of the plurality of adhesive portions are formed between the plurality of protrusions, The method for producing an electromagnetic wave shielding film includes forming the plurality of adhesive portions with the adhesive composition filled in the plurality of recesses.

[0010] [2] The method for producing an electromagnetic wave shielding film according to [1] above, wherein in the adhesive layer forming step, the adhesive composition having curability is used, and the adhesive composition filled in the plurality of recesses is semi-cured to obtain the adhesive portion.

[0011] [3] the electromagnetic wave shielding film includes an outer layer material laminated on the adhesive layer from the side opposite to the adhesive surface, The method for producing an electromagnetic wave shielding film according to the above [1] or [2], further comprising a lamination step of laminating the outer layer material onto the adhesive layer obtained in the adhesive layer forming step.

[0012] [4] the electromagnetic wave shielding film is a strip-shaped release film-attached electromagnetic wave shielding film formed on the release film, the release film has a back surface on which a plurality of convex portions are formed, The method for producing an electromagnetic wave shielding film according to any one of the above [1] to [3], further comprising a winding step of winding the release film-attached electromagnetic wave shielding film into a roll. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a method for producing an electromagnetic wave shielding film that can efficiently form slits in the adhesive layer. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a schematic cross-sectional view of an electromagnetic wave shielding film according to a first embodiment. [Figure 2] FIG. 2 is a schematic cross-sectional view of an electromagnetic wave shielding film according to a second embodiment. [Figure 3] FIG. 10 is a schematic cross-sectional view of an electromagnetic wave shielding film according to a third embodiment. [Figure 4] 1 is a schematic perspective view of an adhesive layer according to each embodiment. FIG. [Figure 5] FIG. 1 is a schematic perspective view of a release film according to an embodiment. [Figure 6] FIG. 1 is a manufacturing flow diagram according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0015] A method for producing an electromagnetic wave shielding film according to an embodiment of the present invention will be described with reference to the drawings.

[0016] First, the electromagnetic wave shielding film, which is a product according to the present embodiment, will be described with reference to Figures 1 to 3. Note that Figure 1 shows a first embodiment, and in the second and third embodiments shown in Figures 2 and 3, the same reference numerals are used to designate the same components as in the first embodiment, and detailed descriptions thereof will be omitted.

[0017] The electromagnetic wave shielding film according to this embodiment is strip-shaped and is cut into pieces according to the size of the adherend surface. Such an electromagnetic wave shielding film may be wound up in a radially overlapping manner around the outer peripheral surface of a cylindrical core material such as a paper tube to form a roll. Hereinafter, the direction in which the electromagnetic wave shielding film extends will be referred to as the length direction, and the two directions perpendicular to the length direction will be referred to as the width direction and the thickness direction.

[0018] As shown in FIG. 1 , an electromagnetic wave shielding film 1a according to a first embodiment includes an adhesive layer 11 that is bonded to an adherend such as a printed circuit board, and an outer layer material 12 that is laminated on the adhesive layer 11. Before use, the electromagnetic wave shielding film 1a is stored in the form of an electromagnetic wave shielding film 100 with a release film 20 superimposed thereon so as to cover the adhesive layer 11. That is, the release film 20 prevents foreign matter from adhering to the adhesive surface of the adhesive layer 11 before use, and prevents the adhesive surface from over-adhering to the back surface of the electromagnetic wave shielding film 1a (the surface of the shielding layer 121 in this embodiment) when the electromagnetic wave shielding film 1a is rolled up. The electromagnetic wave shielding film 1a is configured to be attached to an adherend by thermocompression bonding between the adhesive layer 11, which is exposed when the release film 20 is peeled off from the electromagnetic wave shielding film 100 with a release film, and the adherend, such as a printed circuit board.

[0019] The adhesive layer 11 has a first adhesive surface, which is the first surface that comes into contact with the adherend, and a second surface, which is the opposite surface to the first surface, that is adhered to the outer layer material 12 and forms the interface with the outer layer material 12.

[0020] The outer layer material 12 in the first embodiment is made of a shielding layer 121. That is, the electromagnetic wave shielding film 1a is provided with an outer layer material 12 having a single-layer structure made of a shielding layer 121. The outer layer material 12 has a laminated surface on one of its two surfaces, on which the adhesive layer is laminated. In the first embodiment, the shielding layer 121 is an adjacent layer that contacts the adhesive layer 11.

[0021] The adhesive layer may contain a conductive filler and a binder resin and may be used for electrical continuity between the shielding layer and a ground circuit of a printed circuit board. That is, the adhesive layer may be a conductive adhesive layer. Alternatively, the adhesive layer may not contain a conductive filler and may simply be an insulating layer used to bond the shielding layer and a printed circuit board.

[0022] Examples of the conductive filler include copper particles, silver particles, nickel particles, silver-coated copper particles, gold-coated copper particles, silver-coated nickel particles, gold-coated nickel particles, silver-coated alloy particles, carbon fillers, and metal-coated resin particles.

[0023] The binder resin may be a curable resin or a thermoplastic resin. Examples of the curable resin include phenolic resins, epoxy resins, urethane resins, melamine resins, and alkyd resins. Examples of the thermoplastic resin include polyester resins, polyolefin resins, polystyrene resins, vinyl acetate resins, polyimide resins, polyamide resins, and acrylic resins. The curable resin has reaction curing properties. The curing reaction of the curable resin may be accelerated by, for example, thermal energy or by energy rays such as ultraviolet rays or electron beams. That is, the curable resin may be a thermosetting resin or a photocurable resin.

[0024] When the adhesive layer is a conductive adhesive layer, the content of the conductive filler in the conductive adhesive layer can be, for example, 10% by mass or more. The content here may be 30% by mass or more, or 50% by mass or more. Furthermore, the content here may be 60% by mass or more, or 70% by mass or more. The content here may be 95% by mass or less, 90% by mass or less, or 85% by mass or less.

[0025] The thickness of the adhesive layer is, for example, 0.5 μm or more and 20 μm or less.

[0026] The shielding layer may be a metal layer made of metal, or a conductive layer in which the conductive filler is filled in the binder resin. The metal layer may be allowed to contain unavoidable impurities that do not affect the shielding properties. Such a metal layer may be composed of a metal foil formed by rolling, or may be a deposited film formed by a deposition method such as electroplating, vacuum deposition, sputtering, or CVD. Examples of materials for forming the shielding layer include copper, nickel, silver, tin, gold, palladium, aluminum, chromium, titanium, zinc, and alloys of two or more of these. When the conductive layer is a conductive layer in which the conductive filler is filled in the binder resin, it can be formed using the same formulation as the conductive adhesive layer.

[0027] The thickness of the shield layer is, for example, not less than 0.1 μm and not more than 20 μm.

[0028] 2, an electromagnetic wave shielding film 1b according to a second embodiment includes an outer layer material 12 made up of a shielding layer 121 laminated on an adhesive layer 11 and a protective layer 122 laminated on the shielding layer 121. That is, the electromagnetic wave shielding film 1b includes an outer layer material 12 with a multilayer structure made up of the shielding layer 121 and the protective layer 122. In the second embodiment, the shielding layer 121 is an adjacent layer that contacts the adhesive layer 11.

[0029] The protective layer is insulating (for example, has a volume resistivity of 1×10 at room temperature (23° C.) 12 The protective layer may be a single layer, or may be composed of two or more layers with different compositions or physical properties.

[0030] The protective layer may be formed from an insulating resin composition, which may contain a thermoplastic resin, a curable resin that is cured by heat or light, a polymerization initiator, a curing agent, etc.

[0031] Examples of the thermoplastic resin for the protective layer include polyester resin, polyethylene resin, polypropylene resin, polystyrene resin, vinyl acetate resin, polyamide resin, polyimide resin, and acrylic resin. Examples of the thermosetting resin include epoxy resin, urethane resin, acrylic resin, melamine resin, phenol resin, and polyester resin (unsaturated polyester resin).

[0032] The protective layer has a thickness of, for example, 1 μm or more and 15 μm or less. When the protective layer is composed of two or more layers, the thickness of each protective layer is, for example, 0.5 μm or more and 12 μm or less.

[0033] Next, as shown in Fig. 3, an electromagnetic wave shielding film 1c according to a third embodiment includes an outer layer material 12 made up of an adhesive layer 11 and a protective layer 122 laminated on the adhesive layer 11. That is, the electromagnetic wave shielding film 1c includes an outer layer material 12 with a single-layer structure made up of the protective layer 122. The adhesive layer 11 in the third embodiment is the conductive adhesive layer. In the third embodiment, the protective layer 122 is an adjacent layer that contacts the adhesive layer 11.

[0034] As shown in FIG. 4, the adhesive layer 11 in each embodiment has slits S recessed from the adhesive surface toward the outer layer material 12. The portions where the slits S are formed are portions that are not substantially adhered to the adherend. Therefore, the adhesive surface (first surface) of the adhesive layer 11 has adhesive regions that are adhered to the adherend and non-adhesive regions corresponding to the slits S. The adhesive surface of the adhesive layer 11 shown in FIG. 4 has the lattice-shaped non-adhesive regions and a plurality of rectangular adhesive regions separated by the non-adhesive regions. The adhesive layer 11 has a plurality of adhesive portions 110 that form the adhesive regions. Each adhesive portion 110 has an adhesive surface 111 that contacts the adherend surface and a side surface 112 that rises from the adhesive surface 111 in the thickness direction. The side surface 112 of each adhesive portion 110 faces the side surface 112 of the adjacent adhesive portion 110, and a slit S is formed between the two side surfaces 112. That is, the adhesive layer 11 has a slit S between the opposing side surfaces 112 of the adjacent adhesive portions 110.

[0035] In the embodiment of FIG. 4, each adhesive portion 110 is formed in a rectangular parallelepiped shape. The adhesive portions 110 are arranged in a length direction D1, which is a first direction, to form a slit S extending in a width direction D2. The adhesive portions 110 are also arranged in a width direction D2, which is a second direction intersecting the first direction, to form a slit extending in the length direction D1. The slit S extends to a position corresponding to the adhesive surface 111 of the adhesive layer 11, and forms an opening for releasing gas at that position after the adhesive layer 11 is bonded to the adherend. The slit S also extends to a position corresponding to a side surface of the adhesive layer 11, and forms an opening for releasing gas at that position after the adhesive layer 11 is bonded to the adherend.

[0036] The dimensions and spacing of the multiple adhesive portions 110 of the adhesive layer 11 are adjusted so that the slits S do not disappear due to the inflow of binder resin, etc., even after the adhesive layer 11 has been bonded to the adherend. The slits S after bonding to the adherend then function as passages for allowing gas generated in the adhesive layer 11 and the adherend to flow in, in order to prevent peeling of these layers due to gas accumulating and expanding between the adhesive layer 11 and the outer layer material 12, and between the adhesive layer 11 and the adherend.

[0037] The shape of each adhesive portion in plan view may be rectangular, or may be polygonal such as triangular, pentagonal, or hexagonal, or may be elliptical, circular, or irregular.

[0038] The slits may be formed deep enough to reach the interface between the adhesive layer and the outer layer material, exposing the lamination surface of the outer layer material toward the adhesive surface. That is, the side surfaces of the plurality of adhesive portions may rise from the lamination surface of the outer layer material. In other words, the adhesive layer may be configured with a plurality of independent protrusions that rise from the lamination surface of the outer layer material.

[0039] The slit may be formed so as not to expose the laminated surface of the outer layer material. That is, the adhesive layer may have a bottom covering the laminated surface of the outer layer material and a plurality of protrusions rising from the bottom, the adhesive portion being formed by the plurality of protrusions connected via the bottom, and the slit may be formed only in the bottom portion. In other words, the adhesive layer may have a bottom portion formed between the plurality of adhesive portions and positioned closer to the outer layer material than the adhesive surfaces of the adhesive portions, and the slit may be formed by the side surfaces of the plurality of adhesive portions and the bottom surface of the bottom portion. When the shielding layer is laminated on such an adhesive layer, the shielding layer preferably has a plurality of openings that form gas passages between the shielding layer and the adhesive layer. The plurality of openings may be formed, for example, so as to penetrate the shielding layer in the thickness direction. Furthermore, at least some of the plurality of openings may be connected to at least some of the slits in the adhesive layer.

[0040] The width of each slit is preferably 10 to 1500 μm, more preferably 15 to 900 μm, even more preferably 20 to 600 μm, and even more preferably 25 to 300 μm.

[0041] When the electromagnetic wave shielding film is cut into a film piece to be adhered to an adherend, it is preferable that the cut intersects with at least one of the slits, thereby forming an outlet for releasing gas on the side surface of the adhesive layer in the film piece.

[0042] Next, a method for producing the electromagnetic wave shielding film according to the first embodiment will be described.

[0043] The manufacturing method according to the present embodiment uses an adhesive composition for forming the adhesive layer and a release film on which the adhesive layer is formed. The adhesive composition is preferably curable.

[0044] In the production method of this embodiment, the release film is pulled out from a roll as a raw film, and the adhesive layer or the laminate is formed on the release film as it moves in the length direction, thereby obtaining the roll of the electromagnetic wave shielding film. That is, the production method of this embodiment employs a roll-to-roll method.

[0045] As shown in FIG. 5 , the surface of the release film 20 used in this embodiment has a shape corresponding to the plurality of adhesive portions and the plurality of slits. Specifically, the release film 20 has a surface 201, which is the coated surface on which the adhesive composition is applied, and a back surface 202 opposite the surface 201. The release film 20 also has a plurality of protrusions 21 rising from the surface 201 (coated surface). The plurality of protrusions 21 includes a plurality of first protrusions 211 arranged in the length direction D1 of the release film 20, which corresponds to the first direction, and a plurality of second protrusions 212 arranged in the width direction D2 of the release film 20, which corresponds to the second direction. As a result, the plurality of protrusions 21, together with the surface 201 of the release film 20, form a plurality of recesses 22. That is, the release film 20 has a plurality of recesses 22 formed by the surface 201 and the plurality of protrusions 21. The plurality of recesses 22 is filled with the adhesive composition.

[0046] The width of each protrusion corresponds to the width of the slit, and is preferably 10 to 1500 μm, more preferably 15 to 900 μm, even more preferably 20 to 600 μm, and even more preferably 25 to 300 μm.

[0047] Each of the first protrusions preferably extends across the width of the release film, thereby forming the outlet for gas release on the side surface of the adhesive layer.

[0048] The release film can be formed from a resin material, such as thermosetting resins such as epoxy resins, urethane resins, acrylic resins, melamine resins, phenolic resins, and polyester resins (unsaturated polyester resins), polyester resins such as polyethylene terephthalate (PET), polyolefin resins such as polyethylene resins and polypropylene resins, and thermoplastic resins such as polyamide resins, polybenzimidazole resins (PBI), polyimide resins (PI), fluorine-containing resins (e.g., PTFE), polyamide-imide resins (PAI), aromatic polyether ketone resins (PEEK), and polyphenylene sulfide resins (PPS).

[0049] At least the plurality of protrusions of the release film preferably have a surface that can be peeled from the adhesive layer, and more preferably has a surface that is easily peeled from the adhesive layer. Such a surface can be formed, for example, by a fluorine-based resin such as polytetrafluoroethylene resin (PTFE), a fluorine-based release agent, or a long-chain alkyl acrylate release agent.

[0050] Alternatively, the release film may be obtained by adhering a separate member corresponding to the plurality of protrusions to the surface of a general release film. Examples of general release films include resin films such as polyethylene terephthalate (PET) film, polyethylene film, and polypropylene film. The separate member may be a fiber formed from the above resin. More specifically, the separate member may be a woven or knitted fabric having warp and weft threads. The warp and weft threads are preferably monofilaments.

[0051] The surface of the release film is preferably coated with a release agent such as a fluorine-based release agent or a long-chain alkyl acrylate-based release agent.

[0052] The manufacturing method of this embodiment using such a release film includes an adhesive layer forming step of forming the plurality of adhesive portions in the plurality of recesses. The manufacturing method of this embodiment is efficient because the use of such a release film allows the plurality of adhesive portions to be formed simultaneously.

[0053] 6, the adhesive layer forming process P1 includes a coating process P11 in which the adhesive composition is filled into the recesses, and a drying process P12 as a conversion process in which the solvent contained in the adhesive composition filled into each recess is removed by heating to convert it into the adhesive portions and obtain the adhesive layer. The adhesive layer forming process P1 of this embodiment is efficient because the adhesive composition is divided by the coating process.

[0054] The adhesive composition used in the coating step contains the binder resin, and optionally the conductive particles and a solvent, such as one or more of toluene, acetone, methyl ethyl ketone, methanol, ethanol, propanol, ethyl acetate, propyl acetate, butyl acetate, and dimethylformamide.

[0055] In the coating step, the viscosity of the adhesive composition is preferably adjusted so that the bottom surfaces of the plurality of recesses are completely covered with the coating layer.

[0056] The coating step preferably uses a coating device, such as a gravure roll coater, a reverse roll coater, a kiss roll coater, a lip coater, a dip roll coater, a bar coater, a knife coater, a spray coater, a comma coater, a direct coater, or a slot die coater.

[0057] The coating device used in the coating step of this embodiment is preferably one that can form a coating layer on the surface of the release film without contact, rather than a roll coater, which forms a coating film by contacting the peripheral surface or other portion of the surface of the release film. Examples of such coating devices include a slot die coater. This prevents the partition member from being crushed, making it easier to form an adhesive joint with the designed dimensions.

[0058] The thickness of the coating film formed in the coating step is preferably equal to or greater than the depth of the recesses (the height of the protrusions). Alternatively, the thickness of the coating film may be greater than the depth of the recesses. In this case, a coating film is formed that covers the protrusions of the release film, and ultimately an adhesive layer is formed that covers the protrusions without exposing them. This adhesive layer has a flush surface on the side opposite the adhesive surface, allowing the outer layer material to be easily laminated from the surface side of the release film.

[0059] In the drying step, the solvent contained in the adhesive composition is removed by heating, and the adhesive composition filled in the plurality of recesses is converted into the adhesive portions within the recesses to obtain a release film with an adhesive layer. The protrusions in the release film with an adhesive layer are intended to form slits. Furthermore, in the drying step, the adhesive composition may be semi-cured. If the adhesive portions are in a semi-cured state, unwanted adhesion between the side surfaces of adjacent adhesive portions can be suppressed when the release film is separated during use of the electromagnetic wave shielding film.

[0060] Next, as shown in FIG. 6 , the manufacturing method of this embodiment includes a lamination step P2 following the drying step P12, in which at least one of the shielding layer and the protective layer is laminated as the outer layer material. Here, when slits are formed by irradiating a laser beam onto an adhesive layer with an adjacent shielding layer or protective layer laminated thereon before slit formation, as in the prior art, there is a risk of damaging the adjacent layer with the laser beam. This risk is particularly high when the adhesive layer is thin. In contrast, in this embodiment, an adhesive layer with a slit already formed thereon can be laminated, thereby suppressing damage to the adjacent layer as in the prior art.

[0061] In the lamination step, the outer layer material may be formed on a second release film, which is a new material, and the adhesive layer may be transferred from the release film with the adhesive layer to the outer layer material. The shielding layer may be a metal foil formed by rolling, or may be a deposited film formed by a deposition method such as electroplating, vacuum deposition, sputtering, or CVD.

[0062] In the lamination step, the protective layer may be formed on the second release film, and the adhesive layer may be transferred from the release film with the adhesive layer to the shielding layer. Examples of a method for forming the protective layer include a method in which a coating film is formed using a coating liquid containing the above components and, if necessary, a solvent, and the coating film is cured by heating or light irradiation.

[0063] Furthermore, in the lamination step, the protective layer and the shielding layer may be formed in this order on the second release film, and the adhesive layer may be transferred from the release film with the adhesive layer to the shielding layer.

[0064] The second release film is preferably used as a release film for the electromagnetic wave shielding film. In this case, as shown in Fig. 6, the manufacturing method of this embodiment may include, as a step subsequent to the laminating step P2, a winding step P3 for producing a roll body in which the adhesive layer is disposed on the inner side and the second release film is disposed on the outer side.

[0065] According to the manufacturing method of each of the above-described embodiments, the adhesive composition is not lost due to ablation caused by laser light irradiation in the prior art, and therefore is economical.

[0066] Although one embodiment has been shown above as an example, the method for producing an electromagnetic wave shielding film according to the present invention is not limited to the configuration of the above embodiment. Furthermore, the method for producing an electromagnetic wave shielding film according to the present invention is not limited by the above-mentioned effects. The method for producing an electromagnetic wave shielding film according to the present invention can be modified in various ways without departing from the gist of the present invention. [Explanation of symbols]

[0067] 1a, 1b, 1c: electromagnetic wave shielding film, 11: adhesive layer, 12: outer layer material, 121: shielding layer, 122: protective layer, 100: electromagnetic wave shielding film with release film, 110: adhesive portion, 111: adhesive surface, 112: side, S: slit, 20: release film, 201: surface, 202: back surface, 21: protrusion portion, 211: first protrusion portion, 212: second protrusion portion, 22: recess, P1: adhesive layer forming step, P11: coating step, P12: drying step, P2: lamination step, P3: winding step

Claims

1. A method for producing an electromagnetic wave shielding film comprising an adhesive layer having an adhesive surface to be adhered to an adherend, the adhesive layer having a plurality of adhesive portions separated to form slits, the method comprising: An adhesive layer forming step is provided, In the adhesive layer forming step, a release film is used, and a plurality of protrusions having shapes corresponding to the slits are formed on a surface side of the release film, and a plurality of recesses corresponding to shapes of the plurality of adhesive portions are formed between the plurality of protrusions, The method for producing an electromagnetic wave shielding film includes forming the plurality of adhesive portions with the adhesive composition filled in the plurality of recesses.

2. 2. The method for producing an electromagnetic wave shielding film according to claim 1, wherein in the adhesive layer forming step, the adhesive composition having curability is used, and the adhesive portion is obtained by semi-curing the adhesive composition filled in the plurality of recesses.

3. the electromagnetic wave shielding film includes an outer layer material laminated on the adhesive layer from the side opposite to the adhesive surface, The method for producing an electromagnetic wave shielding film according to claim 1 , further comprising a lamination step of laminating the outer layer material onto the adhesive layer obtained in the adhesive layer forming step.

4. the electromagnetic wave shielding film is a strip-shaped release film-attached electromagnetic wave shielding film formed on the release film, the release film has a back surface on which a plurality of convex portions are formed, The method for producing an electromagnetic wave shielding film according to claim 1 or 2, further comprising a winding step of winding the release film-attached electromagnetic wave shielding film into a roll.

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