JP2019121707A - Electromagnetic wave shield film - Google Patents

Abstract

To realize an electromagnetic wave shield film having high bending resistance.SOLUTION: An electromagnetic wave shield film 101 comprises: a conductive adhesive layer 111; and an insulating protection layer 112 for protecting the conductive adhesive layer 111. The conductive adhesive layer 111 is 100% or more and 500% or less in rupture elongation.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to an electromagnetic wave shielding film.

  In order to protect electronic circuits from electromagnetic noise, an electromagnetic wave shielding film is used which is adhered to the surface of a printed wiring board. The electromagnetic wave shielding film is a laminated body in which a conductive adhesive layer and an insulating protective layer are laminated, and a metal foil or the like may be provided between the conductive adhesive layer and the insulating protective layer. .

  There is a printed circuit board which is repeatedly subjected to a bending operation, such as the connection between the foldable display and the body. The electromagnetic wave shielding film used for such a printed wiring board is required to have high resistance to bending.

  For the purpose of improving the bending resistance of the electromagnetic wave shielding film, it has been attempted to control the particle size and the shape of the conductive filler used in the conductive adhesive layer (see, for example, Patent Document 1).

JP, 2011-187895, A

  However, since various factors influence the bending resistance of the electromagnetic wave shielding film, even if the particle size and shape of the conductive filler are controlled, the bending resistance is not necessarily sufficiently improved.

  An object of the present disclosure is to enable realization of an electromagnetic wave shielding film having high bending resistance.

  One aspect of the electromagnetic wave shielding film of the present disclosure includes a conductive adhesive layer and an insulating protective layer, and the conductive adhesive layer has a breaking elongation of 100% or more and 500% or less.

  In one aspect of the electromagnetic wave shielding film, the conductive adhesive layer can have an elastic modulus of 30 MPa or more and 500 MPa or less.

  In one aspect of the electromagnetic wave shielding film, the total thickness can be 4 μm or more and 20 μm or less.

  One aspect of the electromagnetic wave shielding film may further include a shielding layer provided between the conductive adhesive layer and the insulating protective layer.

  One aspect of the shield wiring substrate of the present disclosure includes a flexible printed wiring substrate having a ground circuit, and the electromagnetic wave shielding film of the present disclosure in which a conductive adhesive layer is connected to the ground circuit.

  According to the electromagnetic shielding film of the present disclosure, the bending resistance can be improved.

It is sectional drawing which shows the electromagnetic wave shield film which concerns on one Embodiment. It is sectional drawing which shows the modification of an electromagnetic wave shielding film. It is sectional drawing which shows the shield wiring board using the electromagnetic wave shielding film which concerns on one Embodiment. It is sectional drawing which shows the board | substrate used for evaluation of the bending resistance of an electromagnetic wave shield film. It is a graph which shows the change rate of the resistance value in a bending resistance test.

  As shown in FIG. 1, the electromagnetic wave shielding film 101 of the present embodiment is a shield provided between the conductive adhesive layer 111, the insulating protective layer 112, and the conductive adhesive layer 111 and the insulating protective layer 112. It has a layer 113. In addition, as shown in FIG. 2, the conductive adhesive layer 111 can function as a shield layer, and it can also be set as the structure in which the independent shield layer is not provided.

  In the present embodiment, the conductive adhesive layer 111 has a breaking elongation of 100% or more, preferably 200% or more. By increasing the breaking elongation of the conductive adhesive layer 111, the resistance to bending (flexibility) is improved, and an increase in connection resistance in the case of repeated bending can be suppressed. From the viewpoint of improving the bending resistance, the breaking elongation is preferably large, but the breaking elongation is 500% or less, preferably 400% or less, from the viewpoint of the resin flow and the embedding in the hole.

  Further, from the viewpoint of further improving the bending resistance, the elastic modulus of the conductive adhesive layer is preferably 500 MPa or less, more preferably 300 MPa or less. The elastic modulus is preferably small from the viewpoint of bending resistance, but the elastic modulus is preferably 30 MPa or more, more preferably 80 MPa or more, from the viewpoint of resin flow and embedding in the hole.

  Furthermore, when the electromagnetic wave shielding film 101 is bent, the stress applied to the shielding layer 113 increases as the thickness of the whole electromagnetic wave shielding film 101 increases. Therefore, from the viewpoint of further improving the bending resistance, the thickness of the entire electromagnetic wave shielding film 101 is preferably 20 μm or less, more preferably 15 μm or less. Even when the shield layer 113 is not provided, the effect of reducing the stress applied to the conductive adhesive layer 111 which functions as a shield layer can be obtained by reducing the overall thickness. From the viewpoint of bending resistance, the smaller the elastic modulus, the better. However, in view of physical limitations, the overall thickness is preferably 4 μm or more, more preferably 6 μm or more. In addition, the thickness of an electromagnetic wave shield film is a value after performing the press which adhere | attaches an electromagnetic wave shield film to a printed wiring board.

  Various methods can be used to set the breaking elongation and elastic modulus of the conductive adhesive layer 111 to such values, and among them, a method of controlling the composition of the conductive adhesive layer 111 is preferable. The main components of the conductive adhesive layer are a resin component such as a thermoplastic resin or a thermosetting resin and a filler component. The filler component is a powder component such as a conductive filler, a flame retardant, and a colorant. By adjusting the addition amount of powder components other than the conductive filler among the filler components, it is possible to control the breaking elongation and the like. In particular, it is preferable that the powder other than the conductive filler does not contain powder having an average particle diameter D50 of 5 μm or more.

  The thermoplastic resin that can be used for the conductive adhesive layer 111 includes, for example, styrene resins, vinyl acetate resins, polyester resins, polyethylene resins, polypropylene resins, imide resins, and acrylic resins as thermoplastic resins. Resin etc. can be mentioned. These resins may be used alone or in combination of two or more.

  As a thermosetting resin which can be used for the conductive adhesive layer 111, for example, a phenol resin, an epoxy resin, a urethane resin, a melamine resin, a polyamide resin and an alkyd resin can be used. Although it does not specifically limit as an active energy ray curable composition, For example, the polymeric compound etc. which have at least 2 (meth) acryloyloxy group in a molecule | numerator can be mentioned. These compositions may be used alone or in combination of two or more.

  The thermosetting resin includes, for example, a first resin component having a reactive first functional group, and a second resin component that reacts with the first functional group. The first functional group can be, for example, an epoxy group, an amido group, or a hydroxyl group. The second functional group may be selected according to the first functional group. For example, when the first functional group is an epoxy group, it may be a hydroxyl group, a carboxyl group, an epoxy group, an amino group or the like. Specifically, for example, when the first resin component is an epoxy resin, an epoxy group modified polyester resin, an epoxy group modified polyamide resin, an epoxy group modified acrylic resin, an epoxy group modified polyurethane polyurea resin, and a carboxyl group as the second resin component. A group modified polyester resin, a carboxyl group modified polyamide resin, a carboxyl group modified acrylic resin, a carboxyl group modified polyurethane polyurea resin, and a urethane modified polyester resin can be used. Among these, carboxyl group modified polyester resin, carboxyl group modified polyamide resin, carboxyl group modified polyurethane polyurea resin, and urethane modified polyester resin are preferable. When the first resin component is a hydroxyl group, an epoxy group modified polyester resin, an epoxy group modified polyamide resin, an epoxy group modified acrylic resin, an epoxy group modified polyurethane polyurea resin, a carboxyl group modified polyester resin as the second resin component, A carboxyl group modified polyamide resin, a carboxyl group modified acrylic resin, a carboxyl group modified polyurethane polyurea resin, a urethane modified polyester resin, etc. can be used. Among these, carboxyl group modified polyester resin, carboxyl group modified polyamide resin, carboxyl group modified polyurethane polyurea resin, and urethane modified polyester resin are preferable.

  The thermosetting resin may contain a curing agent that accelerates the thermosetting reaction. When the thermosetting resin has the first functional group and the second functional group, the curing agent can be appropriately selected according to the types of the first functional group and the second functional group. When the first functional group is an epoxy group and the second functional group is a hydroxyl group, an imidazole-based curing agent, a phenol-based curing agent, a cationic curing agent, or the like can be used. One of these may be used alone, or two or more may be used in combination.

  The conductive filler is not particularly limited, and, for example, metal fillers, metal-coated resin fillers, carbon fillers and mixtures thereof can be used. Examples of the metal filler include copper powder, silver powder, nickel powder, silver-coated copper powder, gold-coated copper powder, silver-coated nickel powder, and gold-coated nickel powder. These metal powders can be produced by an electrolysis method, an atomization method, a reduction method or the like. Among them, silver powder, silver-coated copper powder and copper powder are preferable.

  The conductive filler preferably has an average particle diameter of 1 μm or more, more preferably 3 μm or more, preferably 15 m or less, more preferably 20 μm or less, from the viewpoint of contact between the fillers. The shape of the conductive filler is not particularly limited, and may be spherical, flake-like, dendritic or fibrous.

  The content of the conductive filler can be appropriately selected according to the application, but it is preferably 5% by mass or more, more preferably 10% by mass or more, preferably 95% by mass or less, in the total solid content. It is 90 mass% or less. From the viewpoint of embeddability, it is preferably 70% by mass or less, more preferably 60% by mass or less. Moreover, when realizing anisotropic conductivity, it is preferably 40% by mass or less, more preferably 35% by mass or less.

  In addition, antifoaming agents, antioxidants, viscosity modifiers, diluents, anti-settling agents, leveling agents, coupling agents, coloring agents, flame retardants, etc. as optional components as long as they do not affect breaking elongation etc. May be included.

  The thickness of the conductive adhesive layer 111 is preferably 1 μm to 15 μm from the viewpoint of reducing the thickness of the entire electromagnetic wave shielding film 101.

  The shield layer 113 can be formed of a metal foil, a vapor deposition film, a conductive filler, or the like.

  The metal foil is not particularly limited, and can be a foil made of an alloy containing any of nickel, copper, silver, tin, gold, palladium, aluminum, chromium, titanium, zinc and the like, or two or more.

  The thickness of the metal foil is not particularly limited, but is preferably 0.5 μm or more, and more preferably 1.0 μm or more. When the thickness of the metal foil is 0.5 μm or more, when the high frequency signal of 10 MHz to 100 GHz is transmitted to the shield printed wiring board, the attenuation amount of the high frequency signal can be suppressed. Further, from the viewpoint of reducing the thickness of the entire electromagnetic wave shielding film 101, the thickness of the metal foil is preferably 15 μm or less, more preferably 12 μm or less, and still more preferably 9 μm or less. By reducing the thickness of the metal layer, it is possible to suppress the cost of the raw material, and to obtain the effect of improving the judged elongation of the shield film.

  The deposited film is not particularly limited, and can be formed by depositing nickel, copper, silver, tin, gold, palladium, aluminum, chromium, titanium, zinc and the like. For deposition, electrolytic plating, electroless plating, sputtering, electron beam evaporation, vacuum evaporation, chemical vapor deposition (CVD), metal organic deposition (MOCVD), or the like can be used.

  The deposited film is not particularly limited, and can be formed by depositing nickel, copper, silver, tin, gold, palladium, aluminum, chromium, titanium, zinc and the like. For deposition, electrolytic plating, electroless plating, sputtering, electron beam evaporation, vacuum evaporation, chemical vapor deposition (CVD), metal organic deposition (MOCVD), or the like can be used.

  Although the thickness of a vapor deposition film is not specifically limited, 0.05 micrometer or more is preferable, and 0.1 micrometer or more is more preferable. It is excellent in the characteristic which the electromagnetic wave shield film 101 shields electromagnetic waves in a shield printed wiring board as the thickness of metal vapor deposition film is 0.05 micrometer or more. Further, from the viewpoint of reducing the overall thickness of the electromagnetic wave shielding film 101 to improve the bending resistance, the thickness of the metal deposition film is preferably less than 0.5 μm, and more preferably less than 0.3 μm.

  In the case of the conductive filler, the shield layer 113 can be formed by applying a solvent containing the conductive filler on the surface of the insulating protective layer 112 and drying. As the conductive filler, metal fillers, metal-coated resin fillers, carbon fillers and mixtures thereof can be used. As the metal filler, copper powder, silver powder, nickel powder, silver-coated copper powder, gold-coated copper powder, silver-coated nickel powder, gold-coated nickel powder, etc. can be used. These metal powders can be prepared by an electrolysis method, an atomization method, or a reduction method. The shape of the metal powder may, for example, be spherical, flake, fibrous, dendritic or the like.

  In the present embodiment, the thickness of the shield layer 113 may be appropriately selected according to the required electromagnetic shielding effect and repeated bending / sliding resistance, but in the case of a metal foil, it is 12 μm from the viewpoint of securing breaking elongation. It is preferable to set it as the following.

  In the case where the conductive adhesive layer 111 functions as a shield layer, the shield layer 113 may not be provided.

  The insulating and protective layer 112 is not particularly limited as long as it has sufficient insulating properties and can protect the conductive adhesive layer 111 and the shield layer 113. For example, a thermoplastic resin, a thermosetting resin, or an active energy ray curable resin Or the like.

  The thermoplastic resin is not particularly limited, but a styrene resin, a vinyl acetate resin, a polyester resin, a polyethylene resin, a polypropylene resin, an imide resin, an acrylic resin or the like can be used. The thermosetting resin is not particularly limited, but phenol resins, epoxy resins, urethane resins, melamine resins, polyamide resins, alkyd resins and the like can be used. The active energy ray-curable resin is not particularly limited, but, for example, a polymerizable compound having at least two (meth) acryloyloxy groups in the molecule can be used. The protective layer may be formed of a single material or may be formed of two or more materials.

  The insulating protective layer 112 is not limited to the coloring agent, but if necessary, a curing accelerator, a tackifier, an antioxidant, a plasticizer, an ultraviolet absorber, an antifoamer, a leveling agent, a filler, a flame retardant, viscosity One or more of modifiers, antiblocking agents, etc. may be included.

  The insulating and protective layer 112 may be a laminate of two or more layers having different materials or physical properties such as hardness or elastic modulus. For example, if a laminate of an outer layer with low hardness and an inner layer with high hardness is used, the pressure applied to the shield layer 113 in the process of heating and pressing the electromagnetic wave shield film 101 against the printed wiring board 102 It can be relaxed. For this reason, it can suppress that the shield layer 113 is destroyed by the level | step difference provided in the printed wiring board 102. FIG.

  The thickness of the insulating protective layer 112 is preferably 15 μm or less, more preferably 10 μm or less, and still more preferably 5 μm or less, from the viewpoint of reducing the thickness of the entire electromagnetic wave shielding film 101. From the viewpoint of protecting the conductive adhesive layer 111 and the shield layer 113, the thickness is preferably 1 μm or more, more preferably 2 μm or more.

  The electromagnetic wave shielding film 101 of the present embodiment can be formed, for example, as follows. First, a composition for an insulating protective layer is applied on a supporting substrate (not shown), and then dried by heating to remove the solvent, thereby forming an insulating protective layer 112. The support substrate can be, for example, in the form of a film. The supporting substrate is not particularly limited, and can be formed of, for example, a material such as a polyolefin, polyester, polyimide, polyethylene naphthalate, or polyphenylene sulfide. A release agent layer may be provided between the support substrate and the composition for a protective layer.

  The composition for the insulating protective layer can be prepared by adding an appropriate amount of solvent and other compounding agents to the resin composition for the insulating protective layer. The solvent can be, for example, toluene, acetone, methyl ethyl ketone, methanol, ethanol, propanol and dimethylformamide. As other compounding agents, a crosslinking agent, a polymerization catalyst, a curing accelerator, a coloring agent and the like can be added. Other compounding agents may be added as necessary, and may not be added. The method for applying the composition for a protective layer to the support substrate is not particularly limited, and known techniques such as lip coating, comma coating, gravure coating, or slot die coating can be employed.

  Next, a shield layer 113 is formed on the insulating protection layer 112 as necessary. The method of forming the shield layer 113 can be appropriately selected according to the type of the shield layer 113. When the electromagnetic wave shield film 101 does not have the shield layer 113, this process can be omitted.

  Next, after applying the composition for a conductive adhesive layer on the insulating protective layer 112 or the shield layer 113, the composition is dried by heating to remove the solvent, and a conductive adhesive layer 111 is formed.

  The composition for conductive adhesive layer contains a conductive adhesive and a solvent. The solvent can be, for example, toluene, acetone, methyl ethyl ketone, methanol, ethanol, propanol and dimethylformamide. The ratio of the conductive adhesive in the composition for a conductive adhesive layer may be appropriately set according to the thickness of the conductive adhesive layer 111 or the like.

  The method for applying the composition for a conductive adhesive layer on the shield layer 113 is not particularly limited, and lip coating, comma coating, gravure coating, slot die coating, or the like can be used.

  In addition, you may bond a peeling base material (separate film) together to the surface of the conductive adhesive layer 111 as needed. As the release substrate, a base material such as polyethylene terephthalate or polyethylene naphthalate coated with a silicone-based or non-silicon-based release agent on the surface on which the conductive adhesive layer 111 is to be formed is used. can do. The thickness of the release substrate is not particularly limited, and can be appropriately determined in consideration of ease of use.

  The electromagnetic wave shielding film 101 of the present embodiment can be combined with the printed wiring board 102 as shown in FIG. The electromagnetic wave shielding film 101 may have the shielding layer 113.

  The printed wiring board 102 has, for example, a printed circuit including a base member 122 and a ground circuit 125 provided on the base member 122. An insulating film 121 is adhered on the base member 122 by an adhesive layer 123. The insulating film 121 is provided with an opening for exposing the ground circuit 125. The exposed portion of the ground circuit 125 may be provided with a surface layer such as a gold plating layer. Although the printed wiring board 102 is not particularly limited, it can be a flexible board on which bending is performed.

  When bonding the electromagnetic shielding film 101 to the printed wiring board 102, the electromagnetic shielding film 101 is placed on the printed wiring board 102 so that the conductive adhesive layer 111 is positioned above the opening that exposes the ground circuit 125. Deploy. Then, the electromagnetic wave shield film 101 and the printed wiring board 102 are vertically sandwiched by two heating plates (not shown) heated to a predetermined temperature (for example, 120 ° C.) and a predetermined pressure (for example, 0.5 MPa) ) For a short time (for example 5 seconds). The electromagnetic wave shielding film 101 is temporarily fixed to the printed wiring board 102 by this.

  Subsequently, the temperature of the two heating plates is set to a predetermined temperature (eg, 170 ° C.) higher than that at the time of the temporary fixing, and is pressurized at a predetermined pressure (eg, 3 MPa) for a predetermined time (eg, 30 minutes). By this, the electromagnetic wave shielding film 101 can be fixed to the printed wiring board 102. When the pressure is applied, the conductive adhesive layer 111 is sufficiently embedded in the opening, so that the strength and conductivity required for the electromagnetic shielding film 101 can be realized.

  Hereinafter, the electromagnetic wave shielding film of the present disclosure will be described in more detail using examples. The following examples are illustrative and are not intended to limit the present invention.

<Preparation of electromagnetic wave shield film>
A non-silicon-based release agent was applied to the surface of a predetermined release film to form a release agent layer. Next, the composition for insulating protective layer was applied using a wire bar, and dried by heating to form an insulating protective layer. Next, aluminum was vapor-deposited on the insulating protective layer to form a shield layer having a thickness of 0.15 μm. Next, a predetermined composition for a conductive adhesive layer was applied on the shield layer using a wire bar, and then dried at 100 ° C. for 3 minutes to obtain an electromagnetic wave shielding film.

<Evaluation of bending resistance>
The produced electromagnetic wave shielding film 101 was bonded to the evaluation substrate 201. The bonding was performed using a press at a temperature of 170 ° C. for 30 minutes under a pressure of 2 MPa to 3 MPa. The thickness of the electromagnetic wave shielding film 101 after adhesion is a value obtained by subtracting the thickness of the evaluation substrate 201 from the thickness of the smooth portion of the electromagnetic wave shielding film adhered to the evaluation substrate 201 and the evaluation substrate 201. In addition, thickness was measured based on JISC2151 using the micrometer (made by Mitutoyo, MDH-25), respectively.

  As shown in FIG. 4, the evaluation substrate 201 has a base film 211 having a length of 50 mm, a width of 20 mm, and a thickness of 53 μm, and 5 mm × mutually provided on both ends of the base film 211. It has an electrode 212 of 8 mm. The electrode 212 is connected to the conductive adhesive layer 111 of the electromagnetic wave shielding film 101.

  The resistance value between the test terminals of the evaluation substrate 201 to which the electromagnetic wave shielding film 101 was bonded was measured by using a resistance meter (RM3544-01 manufactured by Toki Denki Co., Ltd.) to obtain an initial resistance value. Next, the substrate for evaluation 201 is bent 180 degrees from the central part, and in this state, a cylindrical weight having a diameter of 5 cm and 1 kg is placed on the substrate for evaluation 201 excluding the electrode 212 and the resistance value is measured during bending. It was measured as a value. After this, the resistance value in the state returned to the original state was measured as a release resistance value. This was repeated 20 times to calculate the rate of change R1 of the resistance at bending and the rate of change R2 of the resistance at release. The rate of change was calculated as (measured value−initial resistance value) / initial resistance value.

<Measurement of physical properties>
The conductive adhesive used to produce the conductive adhesive layer of the electromagnetic wave shielding film was coated on the release film, and the release film was peeled to produce a conductive adhesive layer for test. Dumbbell test pieces (100 mm × 10 mm, 20 mm between marked lines) are prepared from the conductive adhesive layer for test, and using a tensile tester (AGS-X50S, manufactured by Shimadzu Corporation), elastic modulus, elongation at break and maximum stress Was measured. Measurement conditions were set as tensile speed: 50 mm / min, load cell: 50 N, and elastic modulus was calculated from the slope of stress (2 to 3 MPa) and breaking elongation.

Example 1
A conductive adhesive layer with a thickness of 5 μm is formed using a conductive adhesive obtained by adding 43 parts by mass of spherical silver-coated copper powder having an average particle diameter D50 of 5 μm to 100 parts by mass of the thermosetting resin. did. The thickness of the insulating protective layer was 5 μm.

  The whole thickness of the electromagnetic wave shielding film after bonding to the printed wiring board was 8 μm. The breaking elongation of the conductive adhesive layer was 280%, and the elastic modulus of the conductive adhesive layer was 227 MPa. When bending was performed 20 times, the rate of change in resistance R1 at bending was 26%, and the rate of change in resistance R2 at opening was 108%.

(Example 2)
A conductive adhesive layer having a thickness of 17 μm using a conductive adhesive obtained by adding 21 parts by mass of dendritic silver-coated copper powder having an average particle diameter D50 of 13 μm to 100 parts by mass of a thermosetting resin Formed. The thickness of the insulating protective layer was 5 μm.

  The whole thickness of the electromagnetic wave shielding film after bonding to the printed wiring board was 15 μm. The breaking elongation of the conductive adhesive layer was 325%, and the elastic modulus of the conductive adhesive layer was 165 MPa. When bending was performed 20 times, the rate of change in resistance R1 at the time of bending was 31%, and the rate of change in resistance R2 at the time of release was 282%.

(Comparative example 1)
Conductivity obtained by adding 27 parts by mass of dendritic silver-coated copper powder having an average particle diameter D50 of 13 μm to thermosetting resin and 100 parts by mass of resin and 55 parts by mass of nitrogen flame retardant with respect to 100 parts by mass of resin The adhesive was used to form a 17 μm thick conductive adhesive layer. The thickness of the insulating protective layer was 5 μm.

  The whole thickness of the electromagnetic wave shielding film after bonding to the printed wiring board was 15 μm. The breaking elongation of the conductive adhesive layer was 24%, and the elastic modulus of the conductive adhesive layer was 748 MPa. When bending was performed 20 times, the rate of change in resistance R1 at bending was 67%, and the rate of change in resistance R2 at opening was 632%.

  Table 1 shows the results of Examples and Comparative Examples. Moreover, the change rate of the resistance value of each Example and a comparative example is shown in FIG.

  The electromagnetic wave shielding film of the present disclosure has high resistance to bending, and is particularly useful as an electromagnetic wave shielding film or the like for shielding a flexible printed wiring board at a bending portion.

101 electromagnetic wave shield film 102 printed wiring board 103 shield wiring board 111 conductive adhesive layer 112 insulation protective layer 113 shield layer 115 peel film 121 insulating film 122 base member 123 adhesive layer 125 ground circuit 201 substrate for evaluation 211 substrate film 212 Electrode 213 insulation film

Claims (5)

Conductive adhesive layer,
And an insulating protective layer,
The conductive adhesive layer has an elongation at break of 100% or more and 500% or less.   The electromagnetic shielding film according to claim 1, wherein the conductive adhesive layer has an elastic modulus of 30 MPa or more and 500 MPa or less.   The electromagnetic wave shielding film of Claim 1 or 2 whose whole thickness is 4 micrometers or more and 20 micrometers or less.   The electromagnetic wave shielding film according to any one of claims 1 to 3, further comprising a shield layer provided between the conductive adhesive layer and the insulating and protective layer. A flexible printed circuit board having a ground circuit,
The shield wiring board provided with the electromagnetic shielding film according to any one of claims 1 to 4, wherein the conductive adhesive layer is connected to the ground circuit.

Images