TWI731271B - Electromagnetic wave shielding film and shielding printed wiring board - Google Patents

Abstract

The subject of the present invention is to be able to realize an electromagnetic wave shielding film with excellent embedding properties.

The solution of the present invention is: an electromagnetic wave shielding film, which has a conductive adhesive layer and an insulating protective layer. The storage elastic modulus and loss elastic modulus of the insulating protective layer at 120°C, 170°C and 200°C are ^{above 1×10 4} Pa.

Description

Electromagnetic wave shielding film and shielding printed wiring board

Field of invention

This disclosure relates to electromagnetic wave shielding films and shielding printed wiring boards.

Background of the invention

By crimping the electromagnetic wave shielding film to the surface of the printed wiring board, the conductive adhesive layer is embedded in the opening of the insulating film covering the surface of the printed wiring board, so that the conductive adhesive layer and the printed wiring board are grounded The pattern line is turned on. In recent years, with the development of miniaturization of electronic equipment, the size of the opening for embedding the conductive adhesive layer has also been shrinking. Therefore, it is sought to improve the embedding property of the conductive adhesive layer, and various studies have been conducted on the composition and physical properties of the conductive adhesive layer (for example, refer to Patent Document 1).

Prior art literature Patent literature

Patent Document 1: WO2014/010524

Patent Document 2: Japanese Patent Laid-Open No. 2017-92417

Summary of the invention

However, as far as the electromagnetic wave shielding film is concerned, the conductive adhesive layer is Layers of edge protection. Therefore, the physical properties of the insulating protective layer will also affect the embedding of the conductive adhesive layer. With regard to the physical properties of the insulating protective layer, studies have been conducted from the viewpoints such as the adhesion between the insulating protective layer and the conductive adhesive layer and the peelability of the release film (for example, refer to Patent Document 2). However, no discussion has been made from the viewpoint of the embedding property of the conductive adhesive layer.

The subject of this disclosure is to be able to realize an electromagnetic wave shielding film with excellent embedding properties.

One aspect of the electromagnetic wave shielding film of the present disclosure has a conductive adhesive layer and an insulating protective layer. The storage elastic modulus of the insulating protective layer at 120°C, 170°C, and 200°C is 8×10 ⁴ Pa or more, and the loss The modulus of elasticity is all 6×10 ⁴ Pa or more.

In one aspect of the electromagnetic wave shielding film, the storage elastic modulus and loss elastic modulus of the insulating protective layer at 120°C, 170°C, and 200°C can be set to 5×10 ⁶ Pa or less.

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

One aspect of the shielded printed wiring board of the present disclosure includes: a printed wiring board having a grounding circuit and an insulating film, the insulating film having an opening that exposes the grounding circuit; and the electromagnetic wave shielding film of the present disclosure; and, a conductive adhesive The agent layer is bonded to the insulating film in such a way that the ground circuit is conducted in the opening.

According to the insulating protective layer of the present disclosure, conductivity can be realized Electromagnetic wave shielding film with improved adhesive layer embedding.

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: insulating film

122: base member

123: Adhesive layer

125: Ground circuit

128: Opening

140: Printed wiring board for test

141: Copper foil pattern

142: Insulation layer

143: Opening

151: Resistance meter

Fig. 1 is a cross-sectional view showing an electromagnetic wave shielding film according to an embodiment.

Fig. 2 is a cross-sectional view showing a modification of the electromagnetic wave shielding film.

Fig. 3 is a cross-sectional view showing a shielded printed wiring board according to an embodiment.

4 is a cross-sectional view showing the step of attaching the electromagnetic wave shielding film to the printed wiring board.

Figure 5 is a plan view showing the evaluation method of embeddedness.

The form used to implement the invention

The electromagnetic wave shielding film 101 of this embodiment has an insulating protective layer 112 and a conductive adhesive layer 111 as shown in FIG. 1. Such an electromagnetic wave shielding film can make the conductive adhesive layer 111 function as a shield. In addition, as shown in FIG. 2, a shielding layer 113 may be provided between the insulating protection layer 112 and the conductive adhesive layer 111. The shielding layer 113 only needs to be conductive, and it may be a layer of a metal foil, a metal vapor-deposited film, a conductive filler, or the like.

The electromagnetic wave shielding film 101 of this embodiment can be combined with a printed wiring board 102 as shown in FIG. 3 to make a shielding printed wiring board 103. Also, the electromagnetic wave shielding film 101 may be a film having a shielding layer 113.

The printed wiring board 102, for example, has a base member 122 and a printed circuit. The printed circuit is disposed on the base member 122 and includes a ground circuit 125. On the base member 122 by the adhesive layer 123 With an insulating film 121. In addition, 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 part of the ground circuit 125. In addition, the printed wiring substrate 102 may be a flexible substrate or a rigid substrate.

When the electromagnetic wave shielding film 101 is attached to the printed wiring board 102, as shown in FIG. 4, the electromagnetic wave shielding film 101 is arranged on the printed wiring board 102 so that the conductive adhesive layer 111 is located on the opening 128. Then, using two heating plates (not shown) heated to a predetermined temperature (for example, 120°C), sandwich the electromagnetic wave shielding film 101 and the printed wiring board 102 from above and below and run them at a predetermined pressure (for example, 0.5 MPa). Time (for example, 5 seconds) to press. Thereby, the electromagnetic wave shielding film 101 is temporarily fixed to the printed wiring board 102.

Then, set the temperature of the two heating plates to a predetermined temperature (for example, 170° C.) higher than the aforementioned temporary fixation, and pressurize with a predetermined pressure (for example, 3 MPa) 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 the pressure is applied, the conductive adhesive layer 111 is fully embedded in the opening 128, so that the required strength and conductivity of the electromagnetic wave shielding film 101 can be achieved.

In order for the conductive adhesive layer 111 to be fully embedded in the opening 128, the storage elastic modulus and loss elastic modulus of the insulating protective layer 112 become important. Specifically, the storage elastic modulus of the insulating protective layer 112 at 120°C, 170°C, and 200°C is set to 8×10 ⁴ Pa or more, and preferably 1×10 ⁵ Pa or more; the loss elastic modulus is all set It is 6×10 ⁴ Pa or more, and preferably 7×10 ⁴ Pa or more; thereby, the embedding property of the conductive adhesive layer 111 is improved. If the electromagnetic wave shielding film 101 is fixed to the printed wiring board 102 in the temperature range above the pressure temperature and below the reflow temperature, if the insulating protective layer 112 does not have an appropriate storage elastic modulus and loss elastic modulus In this case, the insulating protective layer 112 will absorb the pressure, and the conductive adhesive layer 111 cannot be applied to the lower conductive adhesive layer 111, so that the conductive adhesive layer 111 becomes difficult to be pressed into the connection hole. The maximum temperature applied when the electromagnetic wave shielding film 101 is fixed to the printed wiring board 102 can be set to about 120°C to 200°C, and the reflow temperature can be set to about 240°C to 260°C. Therefore, the storage elastic modulus and loss elastic modulus of the insulating protective layer 112 at 120°C, 170°C, and 200°C become important. In addition, the storage elastic modulus and loss elastic modulus can be measured according to the method shown in the embodiment.

On the other hand, if the storage elastic modulus and loss elastic modulus of the insulating protective layer 112 at the pressurizing temperature are too large, the electromagnetic wave shielding film 101 will become difficult to deform, which makes it difficult for the conductive adhesive layer 111 to be pressed into the connection hole. . Therefore, the storage elastic modulus and loss elastic modulus of the insulating protective layer 112 at 120° C., 170° C., and 200° C. are preferably set to 5×10 ⁶ Pa or less, preferably 3×10 ⁶ Pa or less.

Not only the insulating protective layer 112, but by controlling the storage elastic modulus and loss elastic modulus of the conductive adhesive layer 111, the embedding property of the conductive adhesive layer 111 will be further improved. Specifically, it is advisable to set the storage elastic modulus and loss elastic modulus of the conductive adhesive layer 111 at 120°C, 170°C, and 200°C to 1×10 ⁴ Pa or more, preferably 1×10 ⁵ Pa or more, preferably 5×10 ⁶ Pa or less, more preferably 3×10 ⁶ Pa or less.

In this embodiment, the insulating protective layer 112 can be formed using a thermoplastic resin, a thermosetting resin, or an active energy ray-curing resin, etc., which exhibit predetermined storage elastic modulus and loss elastic modulus. Furthermore, in order to set the storage elastic modulus and loss elastic modulus to predetermined values, an elastic modulus modifier may be added.

Although the thermoplastic resin is not particularly limited, styrene resins, vinyl acetate resins, polyester resins, polyethylene resins, polypropylene resins, imine resins, acrylic resins, etc. can be used. Although there are no particular limitations on the thermosetting resin, phenolic resins, epoxy resins, urethane resins, melamine resins, polyamide resins, alkyd resins, and the like can be used. Although there are no particular limitations on the active energy ray curable resin, for example, a polymerizable compound having at least two (meth)acryloxy 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 modulus of elasticity can be, for example, organic salt, talc, carbon black, silicon dioxide, and the like. These may be used individually by 1 type, and may use 2 or more types together. According to these methods, it becomes easy to set the storage elastic modulus and loss elastic modulus at 120°C, 170°C, and 200°C to predetermined values.

鹽、吡啶鹽、三

鹽及銨鹽等，其中又以三聚氰胺鹽為佳。作為磷酸鹽以外的有機鹽，可使用三聚氰胺三聚氰酸鹽(melamine cyanurate)、三聚氰胺焦磷酸鹽及蜜白胺甲磺酸鹽等，其中又以三聚氰胺三聚氰酸鹽為佳。 Although the organic salt is not particularly limited, phosphates such as polyphosphates and phosphinic acid metal salts are preferred, and metal hypophosphites are more preferred. As the hypophosphorous acid metal salt, aluminum salt, sodium salt, potassium salt, magnesium salt, calcium salt, etc. can be used, among which aluminum salt is preferred. As the polyphosphate, melamine salt, methylamine salt, ethylamine salt, diethylamine salt, triethylamine salt, ethylenediamine salt, piperazine can be used

Salt, pyridine salt, three

Salt and ammonium salt, among which melamine salt is preferred. As the organic salt other than phosphate, melamine cyanurate, melamine pyrophosphate, melam mesylate, etc. can be used. Among them, melamine cyanurate is preferred.

The insulating protective layer 112 may be a laminate of two or more layers having different physical properties such as material, hardness, or elastic modulus. At this time, it is only necessary to make all the layers meet the predetermined storage elastic modulus and loss elastic modulus.

The insulating protective layer 112 may optionally contain hardening accelerators, tackifiers, antioxidants, pigments, dyes, plasticizers, ultraviolet absorbers, defoamers, leveling agents, fillers, flame retardants, and viscosity adjustments. At least one of an agent and an anti-caking agent.

The thickness of the insulating protective layer 112 is not particularly limited, and can be appropriately set as needed, and is preferably 1 μm or more, preferably 4 μm or more, and preferably 20 μm or less, preferably 10 μm or less, and more preferably 5 μm or less. By setting the thickness of the insulating protective layer 112 to be 1 μm or more, the conductive adhesive layer 111 and the shielding layer 113 can be sufficiently protected. By setting the thickness of the insulating protective layer 112 to be 20 μm or less, the electromagnetic wave shielding film 101 can be thinned.

When the shielding layer 113 is provided, the shielding layer 113 can be formed by metal foil, vapor-deposited film, conductive filler, or the like.

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

Although the thickness of the metal foil is not particularly limited, it is preferably 0.5 μm or more, preferably 1.0 μm or more. If the thickness of the metal foil is 0.5μm or more, the attenuation of the high-frequency signal can be suppressed when the high-frequency signal of 10MHz~100GHz is transmitted to the shielded printed wiring board. In addition, the thickness of the metal foil is preferably 12 μm or less, preferably 10 μm or less, and more preferably 7 μm or less. If the thickness of the metal layer is 12μm or less, good fracture elongation can be ensured.

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

Although the thickness of the vapor-deposited film is not particularly limited, it is preferably 0.05 μm or more, and more preferably 0.1 μm or more. When the thickness of the vapor-deposited film is 0.05 μm or more, the electromagnetic wave shielding film has excellent electromagnetic wave shielding characteristics in the shielding printed wiring board. In addition, the thickness of the vapor-deposited film is preferably less than 0.5 μm, more preferably less than 0.3 μm. If the thickness of the vapor-deposited film is less than 0.5 μm, the flex resistance of the electromagnetic wave shielding film is excellent, and the shielding layer can be prevented from being damaged due to the height difference provided on the printed wiring board.

In the case of a conductive filler, the shielding layer 113 can be formed by coating the surface of the insulating protective layer 112 with a solvent blended with the conductive filler and drying it. As the conductive filler, metal fillers, coated metal resin fillers, carbon fillers, and mixtures of these can be used. Copper can be used as metal filler Powder, silver powder, nickel powder, silver-coated copper powder, gold-coated copper powder, silver-coated nickel powder and gold-coated nickel powder, etc. These metal powders can be produced by electrolysis, atomization and reduction methods. The shape of the metal powder can be spherical, flake, fibrous, dendritic, etc.

In this embodiment, the thickness of the shielding layer 113 may be appropriately selected according to the required electromagnetic shielding effect and repeated deflection/slip resistance. However, when it is a metal foil, it is suitable from the viewpoint of ensuring the elongation at break. Set to 12 μm or less.

In this embodiment, the conductive adhesive layer 111 contains at least one of a thermoplastic resin and a thermosetting resin and a conductive filler.

When the conductive adhesive layer 111 contains a thermoplastic resin, as the thermoplastic resin, for example, a styrene-based resin composition, a vinyl acetate-based resin composition, a polyester-based resin composition, a polyethylene-based resin composition, and a polypropylene-based resin can be used. Composition, imine resin composition, acrylic resin composition, etc. These compositions may be used individually by 1 type, and may use 2 or more types together.

When the conductive adhesive layer 111 contains a thermosetting resin, as the thermosetting resin, for example, phenol resin composition, epoxy resin composition, urethane resin composition, melamine resin composition, and alcohol can be used. Acid resin composition, etc. Although the active energy ray curable resin composition is not particularly limited, for example, a polymerizable compound having at least two (meth)acryloyloxy groups in the molecule can be used. These compositions may be used individually by 1 type, and may use 2 or more types together.

Thermosetting resin, for example, contains reactive The first resin component of the first functional group and the second resin component that can react with the first functional group. The first functional group can be, for example, an epoxy group, an amide group, or a hydroxyl group. The second functional group only needs to 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, and the like. Specifically, for example, when the first resin component is epoxy resin, epoxy-modified polyester resin, epoxy-modified polyamide resin, epoxy-modified acrylic resin, and epoxy-modified resin can be used. Polyurethane polyurea resin, carboxyl modified polyester resin, carboxyl modified polyamide resin, carboxyl modified acrylic resin, carboxyl modified polyurethane polyurea resin and urethane modified polyester Resin etc. are used as the 2nd resin component. Among them, carboxyl modified polyester resin, carboxyl modified polyamide resin, carboxyl modified polyurethane polyurea resin and urethane modified polyester resin are preferred. In addition, when the first resin component is a hydroxyl group, epoxy-modified polyester resin, epoxy-modified polyamide resin, epoxy-modified acrylic resin, and epoxy-modified polyurethane can be used. Urea resin, carboxyl modified polyester resin, carboxyl modified polyamide resin, carboxyl modified acrylic resin, carboxyl modified polyurethane polyurea resin, and urethane modified polyester resin as the second Resin component. Among them, carboxyl modified polyester resin, carboxyl modified polyamide resin, carboxyl modified polyurethane polyurea resin and urethane modified polyester resin are preferred.

The thermosetting resin may also contain 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 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, you can Use imidazole hardeners, phenol hardeners, and cationic hardeners. These may be used individually by 1 type, and may use 2 or more types together. In addition, defoamers, antioxidants, viscosity regulators, diluents, anti-settling agents, leveling agents, coupling agents, colorants and flame retardants can also be included as optional ingredients.

Although the conductive filler is not particularly limited, for example, metal fillers, coated metal 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 electrolysis, atomization, reduction, etc. Among them, any one of silver powder, silver-clad copper powder and copper powder is preferred.

From the viewpoint that the fillers are in contact with each other, the average particle diameter of the conductive filler is preferably 1 μm or more, preferably 3 μm or more, and preferably 50 μm or less, and preferably 40 μm or less. The shape of the conductive filler is not particularly limited, and it can be spherical, flake, dendritic, or fibrous.

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

From the viewpoint of embedding property, the thickness of the conductive adhesive layer 111 is preferably 1 μm to 50 μm.

The electromagnetic wave shielding film 101 of this embodiment can be formed in the following manner, for example. First, apply an insulating protective layer on the supporting substrate The composition is then heated and dried to remove the solvent to form the insulating protective layer 112. The supporting substrate can be made into a film shape, for example. The support base material is not particularly limited, and it can be formed using materials such as polyolefin-based, polyester-based, polyimide-based, or polyphenylene sulfide-based materials, for example. A release agent layer may also be provided between the support base material and the protective layer composition.

The composition for the insulating protective layer can be prepared by adding a suitable amount of solvent and other admixtures 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 blending agents, crosslinking agents, polymerization catalysts, hardening accelerators and coloring agents can be added. Other admixtures may be added as needed, and may not be added. The method of coating the protective layer composition on the support substrate is not particularly limited, and lip coating, comma coating, gravure coating, or slot die coating can be used. Of technology.

Secondly, if necessary, a shielding layer 113 is formed on the insulating protection layer 112. The method of forming the shielding layer 113 can be appropriately selected according to the type of the shielding layer 113. When the electromagnetic wave shielding film 101 has a structure without the shielding layer 113, this step can be omitted.

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

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

The method of coating the conductive adhesive layer composition on the shielding layer 113 is not particularly limited, and lip die coating, chamfered wheel coating, gravure coating, slot die coating, or the like can be used.

In addition, if necessary, a release substrate (separation film) may be attached to the surface of the conductive adhesive layer 111. The peeling substrate can use the following: on the base film of polyethylene terephthalate, polyethylene naphthalate, etc., a silicon-based or non-silicon-based release agent is coated on the base film to form conductivity It is formed by adhering the surface on the side of the agent layer 111. In addition, the thickness of the peeling substrate is not particularly limited, and it can be determined in consideration of the ease of use.

Example

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

<Production of electromagnetic wave shielding film>

On the surface of the PET film (thickness 25 μm) provided with a peeling layer, a predetermined insulating protective layer composition was coated with a wire rod and heated and dried to form an insulating protective layer with a predetermined thickness. Next, after coating the predetermined conductive adhesive layer composition on the insulating protective layer with a wire rod, it was dried at 100° C.×3 minutes to prepare an electromagnetic wave shielding film.

<Measurement of storage elastic modulus and loss elastic modulus>

Regarding the insulating protective layer of each embodiment and comparative example, a rheometer (MCR302, manufactured by Anton Paar) was used to measure the range of 30°C to 200°C Determine the dynamic viscoelasticity, and calculate the storage elastic modulus (E”) and loss elastic modulus (G”) at 120℃, 170℃ and 200℃. For the measurement sample system, the insulating protective layer composition was formed into a disc having a diameter of 25 mm and a thickness of 1 mm. In addition, the storage elastic modulus and loss elastic modulus were also measured in the same manner for the conductive adhesive layer.

The measurement conditions are as follows.

Tested plate (plate): D-PP25/AL/S07 diameter 25mm

Swing angle: 0.1%

Frequency: 1Hz

Measuring range: 30~200℃

Heating rate: 6℃/min

<Evaluation of Embeddedness>

As shown in FIG. 5, the electromagnetic wave shielding film 101 is adhered to the test printed wiring board 140 using a pressing machine under the conditions of temperature: 170°C, time: 30 minutes, and pressure: 2 to 3 MPa to produce a shielding printed wiring board. The test printed wiring board 140 has: two copper foil patterns 141, which are provided on a base film (not shown) and extend in parallel with each other at intervals; and an insulating layer (thickness: 25 μm) 142, which covers the copper The foil pattern is made of polyimide; and the insulating layer 142 is provided with an opening 143 that simulates a ground connection with a diameter of 1 mm.

After 5 times of simulated reflow operation of exposing the electromagnetic wave shielding film to 265°C for 1 second, the resistance value between the two copper foil patterns 141 formed on the test printed wiring board 140 was measured by the resistance meter 151, and measured The connection resistance between the copper foil pattern 141 and the electromagnetic wave shielding film 101 is evaluated against The resin embedding property of the opening 143. When the connection resistance value of each opening is less than 0.30Ω, it is judged as good insertability (○), and when it becomes 0.30Ω or more, it is judged as poor insertability (×).

(Example 1)

The composition for the insulating protective layer and the composition for the conductive adhesive are prepared by using a rubber-modified epoxy resin. The thickness of the insulating protective layer is set to 5 μm, and the thickness of the conductive adhesive layer is set to 17 μm.

The storage elastic modulus of the insulating protective layer at 120℃, 170℃ and 200℃ are 1×10 ⁵ Pa, 6×10 ⁵ Pa and 7×10 ⁵ Pa, respectively, and the storage elastic modulus at 120℃, 170℃ and 200℃ The loss elastic modulus are 1×10 ⁵ Pa, 8×10 ⁴ Pa, and 7×10 ⁴ Pa, respectively.

The storage elastic modulus of the conductive conductive adhesive layer at 120℃, 170℃ and 200℃ are 5×10 ⁵ Pa, 1×10 ⁶ Pa and 2×10 ⁶ Pa, respectively, and at 120℃, 170℃ and The loss elastic modulus at 200°C is 3×10 ⁵ Pa, 2×10 ⁵ Pa and 3×10 ⁵ Pa, respectively.

The connection resistance of the obtained electromagnetic wave shielding film is 0.050Ω/1 hole before reflow and 0.060Ω/1 hole after reflow, so the embedding performance is good before and after reflow.

(Example 2)

Except that urethane-modified epoxy resin was used for the insulating protective layer composition, the remaining settings were the same as in Example 1.

The storage elastic modulus of the insulating protective layer at 120°C, 170°C and 200°C is 1×10 ⁶ Pa, 2×10 ⁶ Pa and 2×10 ⁶ Pa, respectively, and the storage elastic modulus at 120°C, 170°C and 200°C The loss elastic modulus are 2×10 ⁵ Pa, 2×10 ⁵ Pa, and 2×10 ⁵ Pa, respectively.

The connection resistance of the obtained electromagnetic wave shielding film is 0.061Ω/1 hole before reflow and 0.089Ω/1 hole after reflow, so the embedding performance is good before and after reflow.

(Example 3)

Except that urethane-modified epoxy resin was used for the insulating protective layer composition, the remaining settings were the same as in Example 1.

The storage elastic modulus of the insulating protective layer at 120℃, 170℃ and 200℃ are 4×10 ⁵ Pa, 6×10 ⁵ Pa and 7×10 ⁵ Pa, respectively, and the storage elastic modulus at 120℃, 170℃ and 200℃ The loss elastic modulus are 1×10 ⁵ Pa, 1×10 ⁵ Pa, and 1×10 ⁵ Pa, respectively.

The connection resistance of the obtained electromagnetic wave shielding film is 0.052Ω/1 hole before reflow and 0.073Ω/1 hole after reflow, so the embedding performance is good before and after reflow.

(Comparative example 1)

Except that an acid anhydride modified polyester resin is used as the resin composition for the insulating protective layer, the other settings are the same as in Example 1.

The storage elastic modulus of the insulating protective layer at 120℃, 170℃ and 200℃ are 5×10 ⁴ Pa, 7×10 ⁴ Pa and 2×10 ⁵ Pa respectively, and the storage elastic modulus at 120℃, 170℃ and 200℃ The loss elastic modulus are 4×10 ⁴ Pa, 4×10 ⁴ Pa, and 5×10 ⁴ Pa, respectively.

The connection resistance of the obtained electromagnetic wave shielding film was 0.33Ω/1 hole before reflow and 0.66Ω/1 hole after reflow, so the embedding performance was poor before and after reflow.

The resulting electromagnetic wave shielding film had poor embedding properties.

The examples and comparative examples are summarized and shown in Table 1.

Industrial availability

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

101: Electromagnetic wave shielding film

111: Conductive adhesive layer

112: insulating protective layer

Claims (3)

An electromagnetic wave shielding film with a conductive adhesive layer and an insulating protective layer; the storage elastic modulus of the aforementioned insulating protective layer at 120°C, 170°C and 200°C is 8×10 ⁴ Pa or more, and the loss elastic modulus They are all above 6×10 ⁴ Pa, and their storage elastic modulus and loss elastic modulus at 120°C, 170°C and 200°C are all below 5×10 ⁶ Pa. The electromagnetic wave shielding film of claim 1, which further has a conductive layer provided between the conductive adhesive layer and the insulating protective layer. A shielded printed wiring board having: a printed wiring board having a grounding circuit and an insulating film, the insulating film having an opening that exposes the grounding circuit; and the electromagnetic wave shielding film of claim 1 or 2; and, the conductive adhesive The agent layer is bonded to the insulating film in such a way that the ground circuit is conducted through the opening.

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