Method for producing 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: An adhesive layer forming step of using a support member having a surface on which the adhesive layer is formed and a partition member including a plurality of partition wall portions having a shape corresponding to the slit, disposing the partition member on the support member to form a plurality of concave portions by the surface of the support member and the plurality of partition wall portions, and forming the plurality of adhesive portions by an adhesive composition filling the plurality of concave portions.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a method for producing 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 support material having a surface on which the adhesive layer is to be formed and a partition material having a plurality of partition wall portions having shapes corresponding to the slits are used, the partition members are disposed on the support member to form a plurality of recesses by the surface of the support member and the plurality of partition wall portions; 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]

[0023] 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 support is a release film; the partition material is separable from the release film; The adhesive layer forming step includes a coating step of forming a coating film of the adhesive composition on the surface of the release film; a filling step of filling the adhesive composition into the recesses by inserting the partition walls of the partition material into the coating film; a converting step of converting the adhesive composition filled in the plurality of recesses into the plurality of adhesive portions; a separation step of separating the partition material from the release film to obtain the adhesive layer in which the slits are formed between the plurality of adhesive portions.

[0013] [5] The method for producing an electromagnetic wave shielding film according to [4] above, wherein the thickness of the partition wall portion is greater than the thickness of the coating film.

[0014] [6] the support is a release film; the partition material is fixed to the release film, The method for producing an electromagnetic wave shielding film according to [3] above, further comprising a separation step of separating the partition material together with the release film from the adhesive layer to obtain the adhesive layer laminated with the outer layer material. [Effects of the Invention]

[0015] 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]

[0016] [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. 2 is a schematic perspective view of a partition member according to the embodiment. [Figure 6] FIG. 2 is a schematic perspective view showing a state in which a partition material according to the embodiment is arranged on a support material. [Figure 7] FIG. 2 is a manufacturing flow diagram of the first embodiment. [Figure 8] FIG. 10 is a manufacturing flow diagram of the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0017] 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.

[0018] 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.

[0019] 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.

[0020] 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 F superimposed thereon so as to cover the adhesive layer 11. That is, the release film F 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 F is peeled off from the electromagnetic wave shielding film 100 with a release film, and the adherend, such as a printed circuit board.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] The thickness of the adhesive layer is, for example, 0.5 μm or more and 20 μm or less.

[0028] The shielding layer is 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 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.

[0029] The thickness of the shield layer is, for example, not less than 0.1 μm and not more than 20 μm.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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).

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] The shape of each adhesive portion in plan view may be, in addition to a rectangle, a polygonal shape such as a triangle, a pentagon, or a hexagon, an ellipse, a perfect circle, or an irregular shape.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] Next, a method for producing the electromagnetic wave shielding film according to the first embodiment will be described.

[0045] The manufacturing method according to the present embodiment uses an adhesive composition for forming the adhesive layer, a release film as a support having a surface on which the adhesive layer is formed, and a partition material for forming the plurality of adhesive portions and the slits. The adhesive composition is preferably curable.

[0046] The partition material used in this embodiment is a separate member that is not integrated with the release film. That is, the partition material is separable from the release film. The partition material is separated from the adhesive layer at least when the electromagnetic wave shielding film is adhered to an adherend.

[0047] As shown in FIGS. 5 and 6 , the partition member 20 of this embodiment has a shape corresponding to the multiple adhesive portions and the slits. Specifically, the partition member 20 has a width equal to or greater than the width of the support member 30 and a length sufficient to simultaneously form multiple adhesive portions aligned in the longitudinal direction D1. The partition member 20 also has multiple partition walls 21 shaped to correspond to the slits. The multiple partition walls 21 include multiple linear first partition walls 211 arranged in the longitudinal direction D1, which corresponds to the first direction, and multiple linear second partition walls 212 arranged in the width direction D2, which corresponds to the second direction. The multiple first partition walls 211 and the multiple second partition walls 212 are formed to intersect with each other. As a result, the partition member 20 has a mesh-like shape in plan view, with multiple openings 22a corresponding to the shapes of the multiple adhesive portions. That is, the partition member 20 has multiple openings 22a arranged adjacent to each other in the longitudinal direction D1 and the width direction D2.

[0048] As shown in Figure 6, the partition material 20 is placed on the surface 31 of the support material 30, and is used so that the surface 31 and the multiple partition walls 21 form multiple recesses 22b. The multiple recesses 22b are filled with the adhesive composition. More specifically, when one side of the partition material 20 is covered with the support material 30, multiple recesses 22b are formed on the side opposite to the side covered by the support material 30, each recess having a side defined by the partition walls 21 and a bottom defined by the surface 31 of the support material 30. Furthermore, by providing a small gap between the surface 31 of the support material 30 and the partition material 20, an electromagnetic wave shielding film can be produced that has an adhesive layer in which the laminate surface of the outer layer material is not exposed at the slit.

[0049] The width of each partition 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.

[0050] Each partition preferably has a thickness (height) greater than the thickness of the coating film of the adhesive composition, which allows the portion located above the coating film to be used as a gripping portion during separation, making it easier to separate the partition material from the adhesive layer.

[0051] It is preferable that each of the first partition portions has a length equal to or greater than the width of the coating film, thereby forming the outlet for releasing gas on the side surface of the adhesive layer.

[0052] The partition material can be made of a metal material or a resin material. Examples of the metal material include iron, stainless steel, aluminum, and copper. Examples of the resin material include thermosetting resins such as epoxy resin, urethane resin, acrylic resin, melamine resin, phenolic resin, and polyester resin (unsaturated polyester resin), polyester resin such as polyethylene terephthalate (PET), polyolefin resin such as polyethylene resin and polypropylene resin, polyamide resin, polybenzimidazole resin (PBI), polyimide resin (PI), fluorine-based resin (e.g., PTFE), polyamideimide resin (PAI), aromatic polyether ketone resin (PEEK), and polyphenylene sulfide resin (PPS).

[0053] At least the partition walls of the partition material preferably have a surface that can be peeled off from the adhesive layer, and more preferably has a surface that is easily peeled off. Such a surface can be formed, for example, from a fluorine-based resin such as polytetrafluoroethylene resin (PTFE), a fluorine-based release agent, or a long-chain alkyl acrylate release agent.

[0054] The partition material may be a perforated resin film, a metal mesh sheet having warp and weft threads, or a woven or knitted fiber fabric. The warp and weft threads are preferably monofilaments.

[0055] The manufacturing method of this embodiment using such a partition material includes an adhesive layer forming step of forming the plurality of adhesive portions with the adhesive composition filled in the plurality of recesses. The adhesive layer forming step of this embodiment is efficient because the use of the partition material allows the plurality of adhesive portions to be formed simultaneously.

[0056] In the manufacturing method of this embodiment, a release film (support material) serving as a roll of raw film is pulled out from the roll, and the adhesive layer and / or the outer layer material are formed on the release film as it moves in the length direction, thereby obtaining a roll of the electromagnetic wave shielding film. That is, the manufacturing method of this embodiment employs a roll-to-roll method.

[0057] As shown in the manufacturing flow diagram of Figure 7, the adhesive layer formation process P1 includes a coating process P11 in which a coating film of the adhesive composition is formed on the surface of the release film, a filling process P12 in which the adhesive composition is filled into the multiple recesses while inserting multiple partition portions of the partition material into the coating film, a drying process P13 which is a conversion process in which the solvent contained in the adhesive composition divided by the partition material is removed by heating to convert it into the adhesive portion and obtain the adhesive layer, and a separation process P14 in which the partition material is separated from the release film.

[0058] The release film may be a commonly used one, such as a resin film including a polyethylene terephthalate (PET) film, a polyethylene film, a polypropylene film, etc. The release film may also be a resin film whose surface is coated with a release agent such as a fluorine-based release agent or a long-chain alkyl acrylate-based release agent, or a paper film.

[0059] 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.

[0060] 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.

[0061] In the filling step, the coating film may be divided by bringing tips of the partition walls of the partition material into contact with the surface of a release film supporting the coating film. For example, a pressure roller may be used to press the partition material against the surface of the release film, and the release film and the partition material may be moved in the direction of travel by the peripheral surfaces of the support roller and the pressure roller, sandwiching them between them, so that the partition walls of the partition material come into contact with the surface of the release film.

[0062] In the filling step, the partition material can be a film with minute through-holes or a perforated film such as a thin nonwoven fabric with a plurality of randomly formed through-holes (e.g., a meltblown nonwoven fabric or a thermal-bonded nonwoven fabric composed of ultrafine fibers). Here, a long strip of perforated film, similar to a release film, can be used as the partition material. In the coating step using such a partition material, a long strip of film laminate, consisting of the release film and the perforated film superimposed on each other, is run in the longitudinal direction, and a roller having an outer peripheral surface is provided midway along the running path to contact the back surface of the film laminate (the surface opposite to the coated surface) and bend (curve) the film laminate in the longitudinal direction. In the coating step, the adhesive composition can be applied to the coated surface of the film laminate bent along the outer peripheral surface of the roller. This enhances adhesion between the release film and the perforated film at the contact points, allowing the adhesive composition to be applied to the perforated film in close contact with the release film. Therefore, it is possible to produce an electromagnetic wave shielding film having an adhesive layer in which the laminate surface of the outer layer material is exposed at the slits.

[0063] When the apertured film is used, at least one of both widthwise ends may be an uncoated portion where the adhesive composition is not applied. By providing such an uncoated portion, the apertured film can be easily peeled off. Alternatively, the apertured film may be used together with the release film as a constituent member of the electromagnetic wave shielding film with a release film, rather than being removed as is, and may be removed together with the release film when the electromagnetic wave shielding film is used.

[0064] The apertured film may be translucent or opaque. The apertured film may have a total light transmittance of 85% or less, or 80% or less. The apertured film may contain a colorant, which can prevent the apertured film from being forgotten to be peeled off.

[0065] In addition to the above, the coating step and the filling step may be performed by a screen printing method. That is, the coating step and the filling step may be performed using a screen material having a plurality of small through holes formed therein, such as a silk screen or a metal mask, as the partition material. Specifically, when the screen material is superimposed on a release film, the through holes in the screen material are blocked from one side by the release film, forming a recess with the release film as the bottom surface. The coating step and the filling step can be performed simultaneously by filling the recess with the adhesive composition using a squeegee.

[0066] In the drying step, the solvent contained in the adhesive composition is removed by heating, and the adhesive composition filled in the multiple recesses is converted into the adhesive portions within the recesses, thereby obtaining a partitioned adhesive layer. The partition portions in the partitioned adhesive layer are intended to form slits. Furthermore, in the drying step, the adhesive composition may be semi-cured to obtain the adhesive portions. This makes it easier for the adhesive portions to be retained on the surface of the release film, making it easier to separate the partition material from the adhesive layer in the subsequent separation step. Furthermore, if the adhesive portions are semi-cured, unwanted adhesion between the side surfaces of adjacent adhesive portions can be suppressed.

[0067] In the separation step, the partition material is separated from the partitioned adhesive layer that has been allowed to cool to room temperature (e.g., 30°C or less), thereby obtaining the adhesive layer in which the slits are formed between the multiple adhesive portions. That is, in the separation step, a film with an adhesive layer from which the partition material has been separated is obtained. Prior to the separation step, the partitioned adhesive layer before separation may be actively cooled using a cooling means such as a blower. This causes the adhesive portions to thermally shrink, and if the partition material is made of a material that is relatively susceptible to thermal shrinkage, such as a resin material, the partition material also thermally shrinks, making it easier to separate the partition material from the adhesive layer.

[0068] When a roll-to-roll method is adopted, an endless partition material may be used, and the filling step through the separation step may be carried out while the coated release film running using an unwinding roller and a winding roller and the rotating partition material are run parallel to each other. In this case, the partition material can be reused. Alternatively, a partition material having both ends in the length direction may be used, and the partition material may be run parallel to the coated release film using an unwinding roller and a winding roller. In this case, the partition material is rolled up by the winding roller and collected, which makes it easy to dispose of the partition material when it is not being used repeatedly.

[0069] Next, as shown in FIG. 7, the manufacturing method of this embodiment includes a laminating step P2 of laminating the outer layer material onto the adhesive layer as the step following the separating step P14.

[0070] In the lamination process, at least one of the shielding layer and the protective layer may be formed on a second release film, which is a new material, as the outer layer material, and the adhesive layer may be transferred from the adhesive layer-coated film to the outer layer material of the second release film. Here, when irradiating a laser beam onto the adhesive layer on which the outer layer material is laminated before slit formation to form slits, as in conventional technology, there is a risk of damaging the outer layer material with the laser beam. The possibility of such damage increases particularly when the adhesive layer is thin. In contrast, in this embodiment, an adhesive layer with slits already formed can be laminated on the outer layer material, thereby suppressing damage to the outer layer material as in conventional technology.

[0071] The second release film is preferably used as a release film for the electromagnetic wave shielding film.

[0072] In forming the shield layer, a metal foil may be formed by rolling, or a deposited film may be formed by a deposition method such as electrolytic plating, vacuum deposition, sputtering, or CVD.

[0073] The protective layer may be formed by forming a coating film using a coating liquid containing the above components and, if necessary, a solvent, and then curing the coating film by heating or irradiating it with light.

[0074] In a modified example of this embodiment, the surface onto which the adhesive composition is applied may be the lamination surface of the outer layer material. That is, the adhesive layer forming step may be performed with the lamination surface of the outer layer material formed on a release film or the like as the surface onto which the adhesive composition is applied. In this case, it is preferable to form the shielding layer of the outer layer material from electrolytic copper foil, and to perform the application step so that the matte surface of the electrolytic copper foil becomes the surface onto which the adhesive composition is applied. This makes it possible to prevent the adhesive composition from peeling off when the partition material is removed.

[0075] Next, a method for producing an electromagnetic wave shielding film according to a second embodiment will be described. Note that the same components as those in the first embodiment will be given the same reference numerals and detailed descriptions thereof will be omitted.

[0076] The partition material used in this embodiment is fixed to the release film, that is, the partition material used in this embodiment is integrated with the release film.

[0077] The manufacturing method of this embodiment using such a partition member includes an adhesive layer forming step of forming the plurality of adhesive portions in the plurality of recesses.

[0078] As shown in Figure 8, the adhesive layer formation process P1 of this embodiment includes a coating process P11 in which the adhesive composition is filled into the multiple recesses, a drying process P13 in which the solvent of the adhesive composition filled into each recess is removed by heating to convert it into the adhesive portion and obtain the adhesive layer, a lamination process P2 in which the outer layer material formed on a second release film is laminated onto the adhesive layer, and a separation process P14 in which the partition material is separated from the adhesive layer together with the release film. This allows the adhesive layer with the slits formed therein to be laminated onto the outer layer material. In the adhesive layer formation process P1 of this embodiment, the adhesive composition is divided into multiple partition portions of the partition material in the coating process P11, so the dividing step can be omitted, which is efficient.

[0079] In the coating process of this embodiment, it is preferable to adjust the viscosity of the adhesive composition so that the adhesive composition flows into the plurality of recesses, i.e., so that the bottom surfaces of the plurality of recesses are covered with the coating layer.

[0080] 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 part of the surface of the release film. Examples of such coating devices include a slot die coater. This prevents the partition material from being crushed, making it easier to form an adhesive joint with the designed dimensions.

[0081] In the adhesive layer forming step of the present embodiment, an adhesive layer having a thickness equal to or greater than the height of the partition wall of the partition material may be formed, which makes it easier to transfer the adhesive layer from the adhesive-layer-attached film to the shielding layer or the protective layer.

[0082] Furthermore, the manufacturing method of this embodiment may include a winding process P3, which is the process following the separation process P14, to produce a roll body in which the adhesive layer is arranged on the inside and the second release film is arranged on the outside.

[0083] 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.

[0084] 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]

[0085] 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, F: release film, 110: adhesive portion, 111: adhesive surface, 112: side surface, S: slit, 20: partition material, 21: partition wall portion, 211: first partition wall portion, 212: second partition wall portion, 22a: opening, 22b: recess, 30: support material, 31: surface, P1: adhesive layer forming step, P11: coating step, P12: filling step, P13: drying step, P14: separation 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 support material having a surface on which the adhesive layer is to be formed and a partition material having a plurality of partition wall portions having shapes corresponding to the slits are used, the partition members are disposed on the support member to form a plurality of recesses by the surface of the support member and the plurality of partition wall portions; 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 support is a release film; the partition material is separable from the release film; The adhesive layer forming step includes a coating step of forming a coating film of the adhesive composition on the surface of the release film; a filling step of filling the adhesive composition into the recesses by inserting the partition walls of the partition material into the coating film; a converting step of converting the adhesive composition filled in the plurality of recesses into the plurality of adhesive portions; a separation step of separating the partition material from the release film to obtain the adhesive layer in which the slits are formed between the plurality of adhesive portions.

5. The method for producing an electromagnetic wave shielding film according to claim 4 , wherein the thickness of the partition wall portion is greater than the thickness of the coating film.

6. the support is a release film; the partition material is fixed to the release film, The method for producing an electromagnetic wave shielding film according to claim 3 , further comprising a separation step of separating the partition material together with the release film from the adhesive layer to obtain the adhesive layer on which the outer layer material is laminated.

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