JP6731393B2 - Electromagnetic wave shielding film - Google Patents

Description

The present disclosure relates to an electromagnetic wave shield film.

When the electromagnetic wave shield film is pressed onto the surface of the printed wiring board, the conductive adhesive layer is embedded in the opening provided in the insulating film covering the surface of the printed wiring board, and the conductive adhesive layer and the printed wiring Conducts electrical connection with the ground pattern on the board. In recent years, as electronic devices have been downsized, the size of the opening in which the conductive adhesive layer is embedded has been reduced. Therefore, the conductive adhesive layer is required to have excellent embedding properties. Further, the conductive adhesive layer is also required to prevent edge breakage due to the step provided on the printed wiring board. Therefore, controlling the fluidity of the conductive adhesive layer to improve the embedding property has been studied (see, for example, Patent Document 1).

International Publication No. 2014/010524

However, the physical properties other than the fluidity also affect the embeddability and edge breakage, but the physical properties other than the fluidity are hardly considered. Further, the electromagnetic wave shielding film is formed by laminating a plurality of layers including an insulating protective layer as well as the conductive adhesive layer. Therefore, in order to improve the embedding property and suppress the edge breakage, it is necessary to optimize the physical properties of the entire electromagnetic wave shielding film.

An object of the present disclosure is to realize an electromagnetic wave shield 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 breaking elongation of 3% or more.

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

One aspect of the electromagnetic wave shielding film may further include a metal vapor deposition layer provided between the conductive adhesive layer and the insulating protective layer, and the breaking elongation may 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 breaking elongation can be 10% or more.

One aspect of a shielded printed wiring board of the present disclosure includes a printed wiring board having a ground circuit and an insulating film having an opening that exposes the ground circuit, and an electromagnetic wave shielding film of the present disclosure, and a conductive adhesive layer Is bonded to the insulating film so as to be electrically connected to the ground circuit in the opening.

According to the electromagnetic wave shielding film of the present disclosure, embeddability 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 shield film. It is sectional drawing which shows the shield printed wiring board which concerns on one Embodiment. It is sectional drawing which shows the process of adhering an electromagnetic wave shield film to a printed wiring board. It is a top view which shows the evaluation method of embedding property.

As shown in FIG. 1, the electromagnetic wave shielding film 101 of this embodiment has an insulating protective layer 112 and a conductive adhesive layer 111. In such an electromagnetic wave shield film, the conductive adhesive layer 111 can function as a shield. Note that, as shown in FIG. 2, a shield layer 113 can be provided between the insulating protective layer 112 and the conductive adhesive layer 111. The shield layer 113 only needs to be conductive, and may be a metal foil, a metal vapor deposition film, a conductive filler layer, or the like.

The electromagnetic wave shielding film 101 of the present embodiment can be combined with a printed wiring board 102 as shown in FIG. 3 to form a shielded printed wiring board 103. The electromagnetic wave shield film 101 may have the shield layer 113.

The printed wiring board 102 has, for example, a base member 122 and a printed circuit including a ground circuit 125 provided on the base member 122. The insulating film 121 is adhered onto the base member 122 with an adhesive layer 123. The insulating film 121 is provided with an opening that exposes the ground circuit 125. A surface layer such as a gold plating layer may be provided on the exposed portion of the ground circuit 125. The printed wiring board 102 may be a flexible board or a rigid board.

When adhering the electromagnetic wave shielding film 101 to the printed wiring board 102, as shown in FIG. 4, the electromagnetic wave shielding film 101 is placed so that the conductive adhesive layer 111 is located above the opening 128. Place it on top. 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). As a result, the electromagnetic wave shielding film 101 is temporarily fixed to the printed wiring board 102.

Then, the temperature of the two heating plates is set to a predetermined temperature (for example, 170° C.) higher than that at the time of temporary fixing, and a predetermined pressure (for example, 3 MPa) is applied for a predetermined time (for example, 30 minutes). Thereby, the electromagnetic wave shielding film 101 can be fixed to the printed wiring board 102. When pressure is applied, the conductive adhesive layer 111 is sufficiently embedded in the opening 128, so that the strength and conductivity required by the electromagnetic wave shielding film 101 can be realized.

Even if 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 extruded to the surroundings and spreads. Therefore, in order to improve the embedding property, it is important that the conductive adhesive layer 111 be deformed and pushed into the opening 128. Therefore, it is preferable that the stress applied to the conductive adhesive layer 111 does not escape to the surroundings. Therefore, it is preferable to increase the elastic modulus of the electromagnetic wave shielding film 101 as a whole so that a large stress is applied to the conductive adhesive layer 111. Specifically, the elastic modulus of the electromagnetic wave shielding film 101 as a whole is 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, not only the conductive adhesive layer 111 but also the electromagnetic wave shielding film 101 including the insulating protective layer 112 and the like are deformed. Therefore, the breaking elongation is set to 3% or more, preferably 4% or more, and more preferably 5% or more so that the electromagnetic wave shielding film 101 as a whole has some flexibility. The elastic modulus is preferably 15,000 MPa or less, more preferably 14900 MPa or less, and further preferably 14800 MPa or less.

The breaking elongation of the electromagnetic wave shield film 101 greatly changes depending on the presence or absence of the shield layer 113 and its material. When the shield layer 113 made of a metal foil is provided, it is difficult to increase the breaking elongation, and it is usually about 10% or less. When the shield layer 113 composed of the metal vapor deposition layer is provided, a larger breaking elongation can be secured, and preferably 10% or more, more preferably 20% or more, still more preferably 30% or more. Elongation at break can be secured. Even when the shield layer 113 is not provided, it is possible to secure a breaking elongation of preferably 10% or more, more preferably 20% or more, still more preferably 30% or more. Further, when the shield layer 113 is not provided, the elastic modulus may be preferably 2000 MPa or less, more preferably 1000 MPa or less. The elastic modulus and elongation at break can be measured by the methods described in the examples.

By setting the elastic modulus and the elongation at break of the electromagnetic wave shielding film 101 to such values, it becomes possible to suppress not only the embedding property but also the occurrence of edge breakage at the step.

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

When the conductive adhesive layer 111 contains a thermoplastic resin, examples of the thermoplastic resin include styrene resin, vinyl acetate resin, polyester resin, polyethylene resin, polypropylene resin, imide resin, and acrylic resin. 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, a phenol resin, an epoxy resin, a urethane resin, a melamine resin, a polyamide resin, an alkyd resin, or the like can be used as the thermosetting resin. .. The active energy ray-curable composition is not particularly limited, but 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 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 amide group, a hydroxyl group, or the like. 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 can 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, the second resin component is 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. A group-modified polyester resin, a carboxyl group-modified polyamide resin, a carboxyl group-modified acrylic resin, a carboxyl group-modified polyurethane polyurea resin, a urethane-modified polyester resin, or the like 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, as the second resin component, 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, a urethane-modified polyester resin and the like 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. These can be used individually by 1 type and can also use 2 or more types together. In addition to these, as an optional component, a defoaming agent, an antioxidant, a viscosity modifier, a diluent, an anti-settling agent, a leveling agent, a coupling agent, a colorant, a flame retardant, and the like may be contained.

The conductive filler is not particularly limited, but, for example, a metal filler, a metal coating 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 coat 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 atomizing method, a reducing method, or the like. Of these, silver powder, silver-coated copper powder and copper powder are preferred.

The conductive filler has an average particle size of preferably 1 μm or more, more preferably 3 μm or more, preferably 50 μm or less, more preferably 40 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-shaped, dendritic, or fibrous.

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

In the present embodiment, the insulating 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 if necessary. For example, a thermoplastic resin or a thermosetting resin can be used. It can be formed using a functional 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, an alkyd resin, or 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 two or more kinds of materials.

The insulating 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 laminated body of an outer layer having a low hardness and an inner layer having a high hardness is used, the outer layer has a cushioning effect, so that the pressure applied to the shield layer 113 in the step of heating and pressing the electromagnetic wave shielding film 101 onto the printed wiring board 102 is reduced. Can be relaxed. Therefore, it is possible to prevent the shield layer 113 from being broken due to the step provided on the printed wiring board 102.

If necessary, the insulating protective layer 112 includes a curing accelerator, a tackifier, an antioxidant, a pigment, a dye, a plasticizer, an ultraviolet absorber, an antifoaming agent, a leveling agent, a filler, a flame retardant, and a viscosity. At least one of a regulator and an antiblocking agent may be contained.

The thickness of the insulating protective layer 112 is not particularly limited and can be appropriately set as necessary, but is preferably 1 μm or more, more preferably 4 μm or more, and preferably 20 μm or less, more preferably 10 μm or less, The thickness can be preferably 5 μm or less. By setting the thickness of the insulating protective layer 112 to 1 μm or more, the conductive adhesive layer 111 and the shield layer 113 can be sufficiently protected. By setting the thickness of the insulating protective layer 112 to 20 μm or less, it becomes easy to set the elastic modulus and the breaking elongation of the electromagnetic wave shielding film 101 to predetermined values.

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

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

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

The thickness of the metal foil is preferably 12 μm or less, more preferably 10 μm or less, and further preferably 7 μm or less. When the thickness of the metal layer is 12 μm or less, raw material costs can be suppressed and the judgment elongation of the shield film becomes good.

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

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

Further, the thickness of the metal vapor deposition film is preferably less than 0.5 μm, and more preferably less than 0.3 μm. When the thickness of the metal vapor deposition film is less than 0.5 μm, the electromagnetic wave shielding film has excellent bending resistance, and it is possible to prevent the shield layer from being broken due to the step provided on the printed wiring board.

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

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

The electromagnetic wave shielding film 101 of this embodiment can be formed as follows, for example. First, the composition for an insulating protective layer is applied onto a supporting substrate, and then dried by heating to remove the solvent to form the insulating protective layer 112. The supporting substrate may be in the form of a film, for example. The supporting base material is not particularly limited, and can be formed of, for example, a polyolefin-based material, a polyester-based material, a polyimide-based material, a polyphenylene sulfide-based material, or the like. A release agent layer may be provided between the supporting substrate and the composition for protective layer.

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

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

Next, after coating the composition for conductive adhesive layer on the insulating protective layer 112 or the shield layer 113, it is heated and dried to remove the solvent to form the conductive adhesive layer 111.

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, dimethylformamide, or the like. The ratio of the conductive adhesive in the conductive adhesive layer composition may be appropriately set according to the thickness of the conductive adhesive layer 111 and the like.
The method for applying the conductive adhesive layer composition onto the shield layer 113 is not particularly limited, and lip coating, comma coating, gravure coating, slot die coating, or the like can be used.

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

A release base material (separate film) may be attached to the surface of the conductive adhesive layer 111, if necessary. As the release base material, a base film made of polyethylene terephthalate, polyethylene naphthalate, or the like, on which a silicone-based or non-silicon-based release agent is applied on the surface on which the conductive adhesive layer 111 is formed, is used. can do. The thickness of the release base material is not particularly limited and can be appropriately determined in consideration of ease of use.

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 invention.

<Production of electromagnetic wave shielding film>
By applying a predetermined insulating protective layer resin composition to the surface of a PET film (thickness 25 μm) provided with a release layer on the surface which is a supporting substrate by using a wire bar and heating and drying, A thick insulating protective layer was formed. After that, when the shield layer was provided, the shield layer was formed on the insulating protective layer by a predetermined method. Next, a predetermined conductive adhesive layer composition was applied onto the insulating protective layer or the shield layer with a wire bar, and then dried at 100° C. for 3 minutes to prepare an electromagnetic wave shielding film.

<Measurement of physical properties>
A dumbbell test piece (100 mm x 10 mm, 20 mm between marked lines) was prepared from the obtained electromagnetic wave shielding film, and the tensile modulus (AGS-X50S, manufactured by Shimadzu Corporation) was used to measure the elastic modulus, elongation at break and maximum stress. It was measured. The measurement conditions were tensile speed: 50 mm/min, load cell: 50 N, and the elastic modulus was calculated from the stress (2 to 3 MPa) and the slope of rupture elongation.

<Evaluation of embeddability>
As shown in FIG. 5, the electromagnetic wave shielding film 101 is adhered to the test printed wiring board 140 using a press machine under the conditions of temperature: 170° C., time: 30 minutes, pressure: 2-3 MPa, and a shielded printed wiring board. Was produced. The test printed wiring board 140 is composed of two copper foil patterns 141 provided on a base film (not shown) and extending in parallel with each other, and an insulating layer (thickness) made of polyimide covering the copper foil patterns. 25 μm) 142, and the insulating layer 142 was provided with an opening 143 simulating a ground connection 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 resistance meter 151, the connection resistance value between the copper foil pattern 141 and the electromagnetic wave shielding film 101 is measured, and the opening The embedding property of the resin in 143 was evaluated. When the connection resistance value per opening was less than 300 mΩ, the embeddability was good (◯), and when the connection resistance value was 300 mΩ or more, the embeddability was poor (x).

(Example 1)
The resin composition for an insulating protective layer is 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. After forming the first insulating protective layer having a thickness of 2 μm, a second insulating protective layer having a thickness of 3 μm was formed on the first insulating protective layer.

The shield layer was a silver vapor deposition film having a thickness of 0.15 μm formed on the surface of the second insulating protective layer by vacuum vapor deposition. The conductive adhesive layer had a resin component of rubber-modified epoxy resin (87 parts by mass), a filler of silver-coated copper powder (13 parts by mass), and a thickness of 17 μm.

The obtained electromagnetic wave shielding film had an elastic modulus of 1311 MPa, a breaking elongation of 45% and a maximum stress of 19 MPa, and the embeddability was good.

(Example 2)
An electromagnetic wave shield 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 μm, and the shield layer was a silver vapor deposition film having a thickness of 0.3 μm.

The obtained electromagnetic wave shielding film had an elastic modulus of 1442 MPa, a breaking elongation of 47% and a maximum stress of 18 MPa, and the embeddability was good.

(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 μm.

The electromagnetic wave shielding film obtained had an elastic modulus of 1235 MPa, a breaking elongation of 94% and a maximum stress of 18 MPa, and the embedding property was good.

(Example 4)
An electromagnetic wave shield 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 μm.

The obtained electromagnetic wave shielding film had an elastic modulus of 825 MPa, a breaking elongation of 69% and a maximum stress of 16 MPa, and the embedding property 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 μm.

The obtained electromagnetic wave shielding film had an elastic modulus of 715 MPa, a breaking elongation of 83% and a maximum stress of 15 MPa, and the embedding property was good.

(Example 6)
The thickness of the second insulating protective layer was 5 μm, the resin component of the conductive adhesive layer was a rubber-modified epoxy resin (40 parts by mass), the filler was silver-coated copper powder (60 parts by mass), and no shield layer was provided. An electromagnetic wave shielding film was produced in the same manner as in Example 2 except for the above.

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

(Example 7)
Same as Example 6 except that the thickness of the second insulating protective layer was 3 μm and the resin component of the conductive adhesive layer was a mixture of rubber-modified epoxy resin and polyester resin (weight ratio 99:1). An electromagnetic wave shielding film was produced.

The elastic modulus of the obtained electromagnetic wave shielding film was 685 MPa, the elongation at break was 71%, the maximum stress was 55 MPa, and the embedding property was good.

(Example 8)
Except that the first insulating protective layer is a phenol-modified epoxy resin having a thickness of 2 μm, the second insulating protective layer is a rubber-modified epoxy resin having a thickness of 5 μm, and the shield layer is a rolled copper foil having a thickness of 5 μm. An electromagnetic wave shielding film was produced in the same manner as in Example 1.

The obtained electromagnetic wave shielding film had an elastic modulus of 14709 MPa, a breaking elongation of 4% and a maximum stress of 53 MPa, and the embeddability was good.

(Example 9)
An electromagnetic wave shield was produced in the same manner as in Example 8 except that the thickness of the rolled copper foil was 2 μm.

The electromagnetic wave shielding film thus obtained had an elastic modulus of 5916 MPa, a breaking elongation of 6% and a maximum stress of 28 MPa, and the embedding property was good.

(Comparative Example 1)
The first insulating protective layer was a urethane-modified epoxy resin having a thickness of 7 μm, and the second insulating protective layer and the shield layer were not provided. The conductive adhesive layer had a resin component of urethane-modified epoxy resin (87 parts by mass), a filler of silver-coated copper powder (13 parts by mass), and a thickness of 17 μm.

The elastic modulus of the obtained electromagnetic wave shielding film was 389 MPa, the elongation at break was 164%, the maximum stress was 17 MPa, and the embeddability was poor.
(Comparative example 2)
Electromagnetic wave shield similar to Comparative Example 1 except that the thickness of the first insulating protective layer was 5 μm, the shield layer was a rolled copper foil having a thickness of 2 μm, and the conductive adhesive layer had a thickness of 12 μm. A film was made.

The obtained electromagnetic wave shielding film had an elastic modulus of 15394 MPa, a breaking elongation of 2% and a maximum stress of 100 MPa, and the embeddability was poor.

Table 1 collectively shows each example and comparative example.

The electromagnetic wave shielding film of the present disclosure has excellent embedding properties and is useful as an electromagnetic wave shielding film for printed wiring boards.

101 Electromagnetic Wave Shield Film 102 Printed Wiring Board 103 Shielded Printed Wiring Board 111 Conductive Adhesive Layer 112 Insulation Protective Layer 113 Shield Layer 121 Insulation Film 122 Base Member 123 Adhesive Layer 125 Ground Circuit 128 Opening 140 Test Printed Wiring Board 141 Copper Foil pattern 142 Insulation layer 143 Opening 151 Resistance meter

Claims (5)

A conductive adhesive layer,
An insulating protective layer,
Comprises a metal foil provided between the conductive adhesive layer and the insulating protective layer,
Tensile modulus of 600 MPa or more,
Der elongation at break of 3% or more is,
The electromagnetic shield film, wherein the insulating protective layer is a thermoplastic resin, a phenol resin, an epoxy resin, a urethane resin, a melamine resin, an alkyd resin, or an active energy ray curable resin . A conductive adhesive layer,
An insulating protective layer,
A metal deposition layer provided on the surface of the insulating protective layer on the side of the conductive adhesive layer,
Tensile modulus of 600 MPa or more,
Der elongation at break of 10% or more is,
The electromagnetic shield film, wherein the insulating protective layer is a thermoplastic resin, a phenol resin, an epoxy resin, a urethane resin, a melamine resin, an alkyd resin, or an active energy ray curable resin . A conductive adhesive layer,
With an insulating protective layer,
The conductive adhesive layer and the insulating protective layer are in contact with each other,
Tensile modulus of 600 MPa or more,
Der elongation at break of 10% or more is,
The electromagnetic shield film, wherein the insulating protective layer is a thermoplastic resin, a phenol resin, an epoxy resin, a urethane resin, a melamine resin, an alkyd resin, or an active energy ray curable resin . The insulating protective layer includes a first layer, and a second layer having a hardness higher than that of the first layer and provided on the conductive adhesive layer side. The electromagnetic wave shielding film according to item 1. A printed wiring board having a ground circuit and an insulating film having an opening exposing the ground circuit,
And a electromagnetic wave shielding film according to any one of claims 1-4,
The shielded printed wiring board, wherein the conductive adhesive layer is bonded to the insulating film so as to be electrically connected to the ground circuit in the opening.

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