KR20190058265A - Electromagnetic wave shield film - Google Patents

Abstract

An objective of the present invention is to realize an electromagnetic wave shielding film which optimizes the overall physical properties. To this end, the electromagnetic wave shielding film (101) comprises a conductive adhesive layer (111) and an insulating protection layer (112). The tension elasticity modulus of the electromagnetic wave shielding film (101) is higher than 400 MPa, and the rupture elongation is higher than or equal to 3%.

Description

Electromagnetic wave shielding film {ELECTROMAGNETIC WAVE SHIELD FILM}

This disclosure relates to an electromagnetic wave shielding film.

The electromagnetic wave shielding film is pressed onto the surface of the printed wiring board so that the conductive adhesive layer is embedded in the opening provided in the insulating film covering the surface of the printed wiring board to electrically conduct the grounding pattern of the conductive adhesive layer and the printed wiring board, . 2. Description of the Related Art In recent years, with the progress of miniaturization of electronic devices, the size of openings for filling conductive adhesive layers has also been reduced. For this reason, excellent filling property is required for the conductive adhesive layer. Further, the conductive adhesive layer is also required to prevent edge cuts from occurring due to steps formed on the printed wiring board. For this reason, it has been studied to control the fluidity of the conductive adhesive layer so as to improve the filling property (see, for example, Patent Document 1).

International Publication No. 2014/010524

However, the properties other than the fluidity are also affected by the filling property and the edge cut, but the properties other than the fluidity are hardly considered. Further, the electromagnetic wave shielding film is formed by laminating not only a conductive adhesive layer but also a plurality of layers including an insulating protective layer. For this reason, in order to improve the filling property and suppress the edge cut, it is necessary to optimize the physical properties of the entire electromagnetic wave shielding film.

An object of the present invention is to realize an electromagnetic wave shielding film having optimized overall physical properties.

One aspect of the electromagnetic wave shielding film of the present disclosure includes a conductive adhesive layer and an insulating protective layer, and has a tensile elastic modulus of 400 MPa or more and a elongation at break of 3% or more.

In one aspect of the electromagnetic wave shielding film, a metal foil provided between the conductive adhesive layer and the insulating protective layer may be further provided.

In one aspect of the electromagnetic wave shielding film, a metal vapor deposition layer provided between the conductive adhesive layer and the insulating protective layer is further provided, and the elongation at break can be 10% or more.

In one aspect of the electromagnetic wave shielding film, the conductive adhesive layer and the insulating protective layer are in contact with each other, and the elongation at break can be 10% or more.

An embodiment of the shielded printed wiring board of the present disclosure includes a printed wiring board having an insulating film having a ground circuit and an opening for exposing the ground circuit and the electromagnetic wave shielding film of the present disclosure, And is bonded to the insulating film so as to be electrically connected to the ground circuit.

According to the electromagnetic wave shielding film of the present disclosure, the filling property can be improved.

1 is a cross-sectional view showing an electromagnetic wave shielding film according to one embodiment.
2 is a cross-sectional view showing a modified example of the electromagnetic wave shielding film.
3 is a cross-sectional view showing a shielded printed wiring board according to one embodiment.
4 is a cross-sectional view showing a step of adhering an electromagnetic wave shielding film to a printed wiring board.
5 is a plan view showing a method for evaluating the filling property.

The electromagnetic wave shielding film 101 of the present embodiment has an insulating protective layer 112 and a conductive adhesive layer 111 as shown in Fig. Such an electromagnetic wave shielding film can make the conductive adhesive layer 111 function as a shield. 2, a shielding layer 113 may be provided between the insulating protective layer 112 and the conductive adhesive layer 111. [ The shielding layer 113 may be made of a conductive material such as a metal foil, a metal evaporated film, or a conductive filler layer.

The electromagnetic wave shielding film 101 of the present embodiment can be used as the shielded printed wiring board 103 in combination with the printed wiring board 102 as shown in Fig. The electromagnetic wave shielding film 101 may have a shielding layer 113.

The printed wiring board 102 has a printed circuit including a base member 122 and a ground circuit 125 provided on the base member 122, for example. An insulating film 121 is adhered to the base member 122 by an adhesive layer 123. The insulating film 121 is provided with an opening for exposing the ground circuit 125. A surface layer such as a gold-plated layer may be formed on the exposed portion of the ground circuit 125. The printed wiring board 102 may be a flexible substrate or a rigid substrate.

The electromagnetic wave shielding film 101 is bonded to the printed wiring board 102 so that the conductive adhesive layer 111 is positioned above the opening 128 as shown in Fig. (102). The electromagnetic wave shielding film 101 and the printed wiring board 102 are sandwiched from above and below by a two heating plates (not shown) heated at a predetermined temperature (for example, 120 DEG C) (For example, 5 seconds) with a predetermined pressure (for example, 0.5 MPa). Thus, the electromagnetic wave shielding film 101 is fixed to the printed wiring board 102.

Subsequently, the temperature of the two heating plates is set to a predetermined temperature (for example, 170 占 폚) higher than the fixed period of time and a predetermined time (for example, 30 Min). As a result, 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 filled in the opening 128, so that the strength and conductivity required by the electromagnetic wave shielding film 101 can be realized.

Even when the fluidity of the conductive adhesive layer 111 is increased, the conductive adhesive layer 111 does not flow into the opening 128 when pressed, but is pushed out and spread out. For this reason, in order to improve the filling property, it is important that the conductive adhesive layer 111 is deformed so as to be pushed into the opening 128. Therefore, it is preferable that the stress applied to the conductive adhesive layer 111 is not scattered to the surroundings. Therefore, it is preferable to increase the elastic modulus of the entire electromagnetic wave shielding film 101 so that a large stress is applied to the conductive adhesive layer 111. More specifically, the modulus of elasticity of the entire electromagnetic wave shielding film 101 is set to 400 MPa or more, preferably 500 MPa or more, and more preferably 600 MPa or more.

On the other hand, when the conductive adhesive layer 111 is pushed into the opening 128, the whole electromagnetic wave shielding film 101 including the insulating protective layer 112 as well as the conductive adhesive layer 111 is deformed. Therefore, the elongation at break is set to 3% or more, preferably 4% or more, and more preferably 5% or more so that the entire electromagnetic wave shielding film 101 has a certain degree of flexibility. The modulus of elasticity is preferably 15000 MPa or less, more preferably 14900 MPa or less, and further preferably 14800 MPa or less.

The elongation at break of the electromagnetic wave shielding film 101 largely changes depending on the presence or absence of the shielding layer 113 and the material thereof. In the case of having a shielding layer 113 made of a metal foil, it is difficult to increase the elongation at break, and it is usually about 10% or less. In the case of having a shielding layer 113 made of a metal deposition layer, it is possible to secure a greater elongation at break, preferably 10% or more, more preferably 20% or more, further preferably 30% We can secure shinto. Even when the shielding layer 113 is not provided, the elongation at break of at least 10%, preferably at least 20%, more preferably at least 30% can be ensured. In the case of not having the shielding layer 113, the modulus of elasticity is preferably not more than 2000 MPa, more preferably not more than 1000 MPa. The modulus of elasticity and elongation at break can be measured by the method described in Examples.

By setting the modulus of elasticity and elongation at break of the electromagnetic wave shielding film 101 to such values, it is possible to suppress not only the filling property but also the occurrence of edge cut at the level difference.

In the present embodiment, the conductive adhesive layer 111 includes a resin component such as a thermoplastic resin and a thermosetting resin, and a conductive filler.

When the conductive adhesive layer 111 includes a thermoplastic resin, for example, a thermoplastic resin such as a styrene resin, a vinyl acetate resin, a polyester resin, a polyethylene resin, a polypropylene resin, an imide resin, Acrylic resin or the like can be used. These resins may be used alone or in combination of two or more.

When the conductive adhesive layer 111 contains a thermosetting resin, for example, a phenol resin, an epoxy resin, a urethane resin, a melamine resin, a polyamide resin and an alkyd resin can be used as the thermosetting resin . The active energy ray curable composition is not particularly limited, and for example, a polymerizable compound having at least two (meth) acryloyloxy groups in the molecule can be used. These compositions may be used alone, or two or more of them may be used in combination.

The thermosetting resin includes, for example, a first resin component having a reactive first functional group and a second resin component reactive with the first functional group. The first functional group may be, for example, an epoxy group, an amide 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, the second functional group 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, A carboxyl 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. Of these, a carboxyl group-modified polyester resin, a carboxyl group-modified polyamide resin, a carboxyl group-modified polyurethane polyurea resin, and a 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, a carboxyl group modified polyester resin, A polyamide resin, a carboxyl group-modified acrylic resin, a carboxyl group-modified polyurethane polyurea resin, and a urethane-modified polyester resin. Of these, a carboxyl group-modified polyester resin, a carboxyl group-modified polyamide resin, a carboxyl group-modified polyurethane polyurea resin, and a urethane-modified polyester resin are preferable.

The thermosetting resin may include a curing agent that promotes the thermosetting reaction. When the thermosetting resin has a first functional group and a second functional group, the curing agent can be appropriately selected depending on the kind 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, and a cationic curing agent can be used. These may be used singly or in combination of two or more kinds. In addition to these, as optional components, a defoaming agent, an antioxidant, a viscosity adjusting agent, a diluting agent, an anti-settling agent, a leveling agent, a coupling agent, a colorant and a flame retardant may be contained.

The conductive filler is not particularly limited, and for example, a metal filler, a metal-coated resin filler, a carbon filler, and a mixture 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 electrolytic method, an atomization method, a reduction method, or the like. Among them, it is preferable to be any one of silver powder, silver coating powder and copper powder.

The conductive filler has an average particle diameter of preferably 1 mu m or more, more preferably 3 mu m or more, preferably 50 mu m or less, and more preferably 40 mu m or less, from the viewpoint of contact between the fillers. The shape of the conductive filler is not particularly limited and may be a spherical shape, a flake shape, a resin shape, a fibrous shape, or the like.

The content of the conductive filler is preferably 5% by mass or more, more preferably 10% by mass or more, preferably 95% by mass or less, more preferably 90% by mass or less, Or less. From the viewpoint of the filling property, it is preferably not more than 70% by mass, more preferably not more than 60% by mass. When anisotropic conductivity is realized, it is preferably 40 mass% or less, and more preferably 35 mass% or less.

In the present embodiment, the insulating protection layer 112 is not particularly limited as long as it has sufficient insulation and can protect the conductive adhesive layer 111 and, if necessary, the shielding layer 113. For example, a thermoplastic resin , A thermosetting resin, or an active energy ray-curable resin.

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 a phenol resin, an epoxy resin, a urethane resin, a melamine resin, or an alkyd resin can be used. The active energy ray curable resin is not particularly limited and, 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 kinds of materials.

The insulating protective layer 112 may be a laminate of two or more layers having different properties such as a material or hardness or modulus of elasticity. For example, in the case of forming a laminate of a low-hardness outer layer and a hard inner layer, the outer layer has a cushioning effect. Therefore, in the step of heating and pressing the electromagnetic-shielding film 101 on the printed wiring board 102, 113 can be relieved. Therefore, breakage of the shielding layer 113 by the step provided on the printed wiring board 102 can be suppressed.

The insulating protective layer 112 may contain a curing accelerator, a tackifier, an antioxidant, a pigment, a dye, a plasticizer, an ultraviolet absorber, a defoaming agent, a leveling agent, a filler, a flame retardant, a viscosity modifier, May be included.

The thickness of the insulating protective layer 112 is not particularly limited and may be appropriately set as necessary. The thickness of the insulating protective layer 112 is preferably 1 占 퐉 or more, more preferably 4 占 퐉 or more, and preferably 20 占 퐉 or less May be 10 mu m or less, more preferably 5 mu m or less. When the thickness of the insulating protection layer 112 is 1 占 퐉 or more, the conductive adhesive layer 111 and the shielding layer 113 can be sufficiently protected. By setting the thickness of the insulating protection layer 112 to be not more than 20 占 퐉, it becomes easy to set the elastic modulus and the elongation at break of the electromagnetic wave shielding film 101 to a predetermined value.

When the shielding layer 113 is provided, the shielding layer 113 can be formed of a metal foil, a metal vapor deposition film, and an electrically conductive filler.

The metal foil is not particularly limited and may be a foil made of an alloy containing any one or more of nickel, copper, silver, tin, gold, palladium, aluminum, chromium, titanium, have.

The thickness of the metal foil is not particularly limited, but is preferably 0.5 탆 or more, more preferably 1.0 탆 or more. When the thickness of the metal foil is 0.5 탆 or more, the amount of attenuation of the high-frequency signal can be suppressed when a high-frequency signal of 10 MHz to 100 GHz is transmitted to the shielded printed wiring board.

The thickness of the metal foil is preferably 12 占 퐉 or less, more preferably 10 占 퐉 or less, and further preferably 7 占 퐉 or less. When the thickness of the metal layer is 12 mu m or less, the cost of the raw material can be suppressed, and the breaking elongation of the shielding film becomes good.

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

The thickness of the metal vapor deposition film is not particularly limited, but is preferably 0.05 탆 or more, more preferably 0.1 탆 or more. When the thickness of the metal vapor deposition film is 0.05 m or more, the electromagnetic shielding film of the shielded printed wiring board is excellent in shielding electromagnetic waves.

The thickness of the metal vapor deposition film is preferably less than 0.5 mu m, more preferably less than 0.3 mu m. When the thickness of the metal vapor deposition film is less than 0.5 mu m, the electromagnetic wave shielding film is excellent in bending resistance, and breakage of the shielding layer due to the step provided on the printed wiring board can be suppressed.

In the case of the conductive filler, the shielding layer 113 can be formed by applying a solvent containing a conductive filler to the surface of the insulating protective layer 112 and drying the applied coating. As the conductive filler, a metal filler, a metal-coated resin filler, a carbon filler and a mixture thereof can be used. As the metal filler, copper powder, silver powder, nickel powder, silver coating powder, gold coated copper powder, silver-coated nickel powder, and gold-coated nickel powder can be used. These metal powders can be prepared by an electrolytic method, an atomization method, or a reduction method. Examples of the shape of the metal powder include spherical, flaky, fibrous, dendritic, and the like.

In the present embodiment, the thickness of the shielding layer 113 may be suitably selected in accordance with the required electromagnetic shielding effect and repetitive bending and sliding resistance. In the case of metal foil, however, .

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 coated on a supporting substrate (substrate), followed by drying by heating to remove the solvent to form an insulating protective layer 112. The supporting substrate may be, for example, a film type. The supporting substrate is not particularly limited and can be formed of, for example, a polyolefin-based, polyester-based, polyimide-based, or polyphenylene sulfide-based material. A release agent layer may be provided between the support substrate and the composition for the protective layer.

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

Next, a shielding layer 113 is formed on the insulating protection layer 112 as necessary. The method of forming the shielding layer 113 can be appropriately selected depending on the type of the shielding layer 113. [ In the case where the electromagnetic wave shielding film 101 has no shielding layer 113, this step can be omitted.

Next, a composition for a conductive adhesive layer is coated on the insulating protection layer 112 or the shielding layer 113, and then the conductive adhesive layer 111 is formed by removing the solvent by heating and drying.

The composition for a conductive adhesive layer includes a conductive adhesive agent and a solvent. The solvent may be, for example, toluene, acetone, methyl ethyl ketone, methanol, ethanol, propanol, and dimethylformamide. The proportion of the conductive adhesive in the composition for the conductive adhesive layer may be appropriately set depending on the thickness of the conductive adhesive layer 111 and the like.

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

The thickness of the conductive adhesive layer 111 is preferably 1 m to 50 m from the viewpoint of controlling the elastic modulus and elongation at break of the electromagnetic wave shielding film 101. [

If necessary, a release substrate (separate film) may be bonded to the surface of the conductive adhesive layer 111. As the release substrate, a silicone or non-silicone release agent coated on the surface of the side where the conductive adhesive layer 111 is formed may be used on a base film such as polyethylene terephthalate or polyethylene naphthalate. The thickness of the release substrate is not particularly limited, and can be appropriately determined in consideration of ease of use.

[Example]

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

<Fabrication of electromagnetic wave shielding film>

A predetermined insulating protective layer resin composition was applied to the surface of a PET film (thickness 25 占 퐉) provided with a release layer on the surface of a supporting substrate using a wire bar and dried by heating to form an insulating protective layer having a predetermined thickness did. Thereafter, when a shielding layer is provided, a shielding layer is formed on the insulating protective layer by a predetermined method. Next, a predetermined composition for a conductive adhesive layer was applied on the insulating protective layer or the shielding layer by a wire bar, and then dried at 100 DEG C for 3 minutes to produce an electromagnetic wave shielding film.

&Lt; Measurement of physical properties &

The elastic modulus, elongation at break, and maximum stress were measured using a tensile tester (AGS-X50S, Shimazu Seisakusho) manufactured from a dumbbell test piece (100 mm x 10 mm, . The measurement conditions were a tensile speed of 50 mm / min and a load cell of 50 N, and a modulus of elasticity was calculated from the stress (2 to 3 MPa) and the slope of the elongation at break.

&Lt; Evaluation of landfillability &

The electromagnetic wave shielding film 101 was bonded to the test printed wiring board 140 using a press machine under the conditions of a temperature of 170 DEG C and a time of 30 minutes and a pressure of 2 to 3 MPa, A printed wiring board was produced. The test printed wiring board 140 includes two copper foil patterns 141 extending parallel to each other and provided on a base film (not shown) and an insulating layer made of polyimide covering the copper foil pattern (thickness: 25 The insulating layer 142 is provided with an opening 143 simulating a ground connection portion having a diameter of 1 mm.

The electrical resistance value between the two copper foil patterns 141 formed on the test printed wiring board 140 is measured by the ohmmeter 151 and the connection resistance value between the copper foil pattern 141 and the electromagnetic wave shielding film 101 is measured, The filling property of the resin into the opening 143 was evaluated. The embedding property was evaluated as good (O) when the connection resistance value per one opening was less than 300 m OMEGA, and the embedding property was evaluated as poor (X) when the connection resistance value was 300 m OMEGA or more.

(Example 1)

The resin composition for an insulating protective layer was made from a resin composition for a first insulating protective layer made of a UV-curable acrylic resin and a resin composition for a second insulating protective layer made of a rubber-modified epoxy resin, and a first insulation protection Layer was formed, a second insulating protective layer having a thickness of 3 m was formed on the first insulating protective layer.

The shielding layer was a silver deposited film having a thickness of 0.15 占 퐉 formed by vacuum evaporation on the surface of the second insulating protection layer. The conductive adhesive layer was made of a rubber-modified epoxy resin (87 parts by mass) as a resin component and a silver coating active ingredient (13 parts by mass) as a filler, and the thickness was 17 占 퐉.

The obtained electromagnetic wave shielding film had a modulus of elasticity of 1311 MPa, a elongation at break of 45%, and a maximum stress of 19 MPa.

(Example 2)

An electromagnetic wave shielding film was produced in the same manner as in Example 1 except that the first insulating protective layer was an epoxy-modified polyester resin having a thickness of 2 m and the shielding layer was a silver vapor-deposited film having a thickness of 0.3 m.

The obtained electromagnetic wave shielding film had a modulus of elasticity of 1442 MPa, a breaking elongation of 47%, and a maximum stress of 18 MPa.

(Example 3)

An electromagnetic wave shielding film was produced in the same manner as in Example 2 except that the thickness of the conductive adhesive layer was 5 mu m.

The obtained electromagnetic wave shielding film had a modulus of elasticity of 1235 MPa, a elongation at break of 94%, and a maximum stress of 18 MPa.

(Example 4)

An electromagnetic wave shielding film was produced in the same manner as in Example 1 except that the first insulating protective layer was an epoxy-modified polyester resin having a thickness of 2 탆.

The obtained electromagnetic wave shielding film had a modulus of elasticity of 825 MPa, a elongation at break of 69%, and a maximum stress of 16 MPa, and the embeddability was good.

(Example 5)

An electromagnetic wave shielding film was produced in the same manner as in Example 4 except that the thickness of the conductive adhesive layer was 5 mu m.

The obtained electromagnetic wave shielding film had a modulus of elasticity of 715 MPa, an elongation at break of 83%, and a maximum stress of 15 MPa.

(Example 6)

The thickness of the second insulating protective layer was 5 占 퐉, the resin component of the conductive adhesive layer was rubber-modified epoxy resin (40 parts by mass), the filler was silver-coated copper component (60 parts by mass) The procedure of Example 2 was otherwise repeated to produce an electromagnetic wave shielding film.

The obtained electromagnetic wave shielding film had a modulus of elasticity of 404 MPa, an elongation at break of 119%, and a maximum stress of 25 MPa.

(Example 7)

Except that the thickness of the second insulating protection layer was 3 mu m and the resin component of the conductive adhesive layer was a mixture of rubber-modified epoxy resin and polyester resin (99: 1 by weight ratio) A film was produced.

The obtained electromagnetic wave shielding film had a modulus of elasticity of 685 MPa, a elongation at break of 71%, and a maximum stress of 55 MPa.

(Example 8)

Except that the first insulating protective layer was a phenol-modified epoxy resin with a thickness of 2 탆, the second insulating protective layer was a rubber-modified epoxy resin with a thickness of 5 탆, and the shielding layer was a rolled copper foil with a thickness of 5 탆, To prepare an electromagnetic wave shielding film.

The obtained electromagnetic wave shielding film had a modulus of elasticity of 14709 MPa, a breaking elongation of 4%, and a maximum stress of 53 MPa.

(Example 9)

An electromagnetic wave shielding film was produced in the same manner as in Example 8 except that the rolled copper foil had a thickness of 2 탆.

The obtained electromagnetic wave shielding film had a modulus of elasticity of 5,916 MPa, an elongation at break of 6%, and a maximum stress of 28 MPa.

(Comparative Example 1)

The first insulating protective layer was made of a urethane-modified epoxy resin having a thickness of 7 탆, and the second insulating protective layer and the shielding layer were not provided. The electrically conductive adhesive layer was made of urethane-modified epoxy resin (87 parts by mass) as a resin component, and silver paste (13 parts by mass) as a filler, and the thickness thereof was 17 占 퐉.

The obtained electromagnetic wave shielding film had a modulus of elasticity of 389 MPa, an elongation at break of 164%, and a maximum stress of 17 MPa.

(Comparative Example 2)

The electromagnetic wave shielding film was produced in the same manner as in Comparative Example 1 except that the thickness of the first insulating protective layer was 5 占 퐉, the shielding layer was a rolled copper foil having a thickness of 2 占 퐉, and the thickness of the electrically conductive adhesive layer was 12 占 퐉. .

The obtained electromagnetic wave shielding film had a modulus of elasticity of 15394 MPa, a elongation at break of 2%, and a maximum stress of 100 MPa.

Table 1 summarizes each example and comparative example.

[Table 1]

The electromagnetic wave shielding film of the present disclosure has excellent filling property and is useful as an electromagnetic wave shielding film for a printed wiring board.

101: Electromagnetic wave shielding film
102: printed wiring board
103: Shielded printed wiring board
111: Conductive adhesive layer
112: insulating protective layer
113: shielding layer
121: Insulation film
122: base member
123: adhesive layer
125: Ground circuit
128: opening
140: Printed wiring board for test
141: Copper foil pattern
142: insulating layer
143: opening
151: Resistance meter

Claims (5)

A conductive adhesive layer and an insulating protective layer,
A tensile modulus of elasticity of 400 MPa or more,
An electromagnetic wave shielding film having a breaking elongation of 3% or more. The method according to claim 1,
And a metal foil provided between the conductive adhesive layer and the insulating protective layer. The method according to claim 1,
Further comprising a metal deposition layer provided between the conductive adhesive layer and the insulating protective layer, wherein the elongation at break is 10% or more. The method according to claim 1,
Wherein the conductive adhesive layer and the insulating protective layer are in contact with each other,
An electromagnetic wave shielding film having a breaking elongation of 10% or more. A printed circuit board having an insulating film having a ground circuit and an opening for exposing the ground circuit;
An electromagnetic wave shielding film comprising the electromagnetic wave shielding film according to any one of claims 1 to 4,
Wherein the conductive adhesive layer is bonded to the insulating film so as to conduct with the ground circuit in the opening.

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