KR20190116972A - Electromagnetic shielding film, shielded printed wiring boards and electronic equipment - Google Patents

Abstract

An object of this invention is to provide the electromagnetic wave shielding film which has sufficient bending resistance, and is high enough electromagnetic wave shielding characteristic.
The electromagnetic wave shielding film of this invention is an electromagnetic wave shielding film which consists of a conductive adhesive layer, the shielding layer laminated | stacked on the said conductive adhesive layer, and the insulating layer laminated | stacked on the said shielding layer, The said shielding layer is provided with the some opening part. In the MIT anti-fatigue test specified in JIS P8115: 2001, no break occurs at 600 bending times, and the electromagnetic shielding property of the electromagnetic shielding film at 200 MHz measured by the KEC method is 85 dB or more. .

Description

Electromagnetic shielding film, shielded printed wiring boards and electronic equipment

The present invention relates to an electromagnetic wave shielding film, a shielded printed wiring board, and an electronic device.

Conventionally, for example, attaching an electromagnetic wave shielding film to printed wiring boards, such as a flexible printed wiring board (FPC), and shielding the electromagnetic wave from the exterior is performed.

The electromagnetic wave shielding film usually has a structure in which a conductive adhesive layer, a shielding layer made of a metal thin film, and the like, and an insulating layer are laminated in this order. By heat-pressing this electromagnetic wave shielding film in the state superimposed on a printed wiring board, an electromagnetic wave shielding film is adhere | attached to a printed wiring board with an adhesive bond layer, and a shielding printed wiring board is produced. After the adhesion, the components are mounted on the printed wiring board by solder reflow. Moreover, the printed wiring board has the structure by which the print pattern on the base film was coat | covered with the insulating film.

When manufacturing a shielding printed wiring board, when a shielding printed wiring board is heated by a hot press or solder reflow, gas will generate | occur | produce from the electrically conductive adhesive bond layer of an electromagnetic wave shielding film, the insulating film of a printed wiring board, etc. Moreover, when the base film of a printed wiring board is formed from resin with high hygroscopicity, such as polyimide, water vapor may generate | occur | produce from a base film by heating. Since these volatile components which generate | occur | produced from an electroconductive adhesive bond layer, an insulation film, or a base film cannot pass through a shielding layer, it accumulates between a shielding layer and a conductive adhesive layer. Therefore, if rapid heating is performed in the solder reflow step, the interlayer adhesion between the shielding layer and the conductive adhesive layer may be destroyed by the volatile components accumulated between the shielding layer and the conductive adhesive layer, and the shielding characteristics may be degraded.

In order to solve such a subject, patent document 1 describes the electromagnetic wave shielding film which provided the some opening part in the shielding layer (metal thin film), and improved air permeability.

If a plurality of openings are formed in the shielding layer, even if a volatile component is generated, the volatile component can pass through the shielding layer through the opening. Therefore, it is possible to prevent the volatile components from accumulating between the shielding layer and the conductive adhesive layer, and to prevent the deterioration of the shielding property due to the breakage of the interlayer adhesion.

International Publication No. 2014/192494

However, since the opening part is formed in the shielding layer of the electromagnetic wave shielding film of patent document 1, the strength of a shielding layer is weak.

Therefore, when the electromagnetic wave shielding film of patent document 1 is used for a flexible printed wiring board, the following problems arise.

That is, the flexible printed wiring board is repeatedly bent at the time of use. The electromagnetic wave shielding film used for such a flexible printed wiring board, and the shielding layer which comprises this electromagnetic wave shielding film are also bent repeatedly.

As mentioned above, since the shielding layer of the electromagnetic wave shielding film of patent document 1 is weak in strength, when it is bent repeatedly, there existed a problem that a shielding layer was easy to be destroyed.

In addition, the electromagnetic wave shielding film of patent document 1 was not able to say that shielding characteristic is high enough.

This invention is made | formed in view of the said subject, and the objective of this invention is providing the electromagnetic wave shielding film which has sufficient bending resistance, and its electromagnetic wave shielding characteristic is high enough.

That is, the electromagnetic wave shielding film of this invention is an electromagnetic wave shielding film which consists of a conductive adhesive layer, the shielding layer laminated | stacked on the said conductive adhesive layer, and the insulating layer laminated | stacked on the said shielding layer, A some opening part is formed in the said shielding layer. In the MIT anti-fatigue test specified in JIS P8115: 2001, no break occurs at 600 bending times, and the electromagnetic shielding film at 200 MHz measured by the KEC method. Electromagnetic shielding characteristics are characterized in that more than 85dB.

In the electromagnetic wave shielding film of this invention, the some opening part is formed in the shielding layer.

Therefore, even when a volatile component is generated between the shielding layer and the conductive adhesive layer in the heat press step, the solder reflow step, or the like when the shielding printed wiring board is manufactured using the electromagnetic shielding film of the present invention, the volatile component may be formed of the shielding layer. It may pass through the opening.

Therefore, a volatile component becomes difficult to accumulate between a shielding layer and a conductive adhesive layer. As a result, breakage of interlayer adhesion can be prevented. Therefore, the electromagnetic wave shielding characteristic at 200 MHz measured by the KEC method mentioned later becomes high.

In addition, the electromagnetic wave shielding film of this invention does not generate a disconnection when the frequency | count of bending is 600 times in the MIT rupture fatigue test prescribed | regulated to JISP8115: 2001.

When the electromagnetic wave shielding film of this invention has such high bending resistance, even if the electromagnetic wave shielding film of this invention is used for a flexible printed wiring board etc., disconnection does not occur easily.

The electromagnetic wave shielding film of this invention is 85 dB or more in the electromagnetic shielding characteristic in 200 MHz measured by the KEC method. That is, it has a sufficiently high shielding characteristic.

In addition, the "KEC method" means the following method.

FIG. 1: is a schematic diagram which shows typically the structure of the system used by the KEC method.

The system used in the KEC method includes an electromagnetic wave shielding effect measuring device 80, a spectrum analyzer 91, an attenuator 92 for attenuating 10 dB, an attenuator 93 for attenuating 3 dB, It consists of a preamp 94.

As shown in FIG. 1, two measuring jigs 83 are provided in the electromagnetic shielding effect measuring apparatus 80 so as to face each other. Between these measurement jig 83, it installs so that an electromagnetic wave shielding film (it may show as 110 in FIG. 1) is clamped. In the measurement jig 83, the dimensional distribution of the TEM cell (Transverse Electro Magnetic Cell) is introduced, and the structure is divided into left and right symmetry in the plane perpendicular to the transmission axis direction. However, in order to prevent the short circuit from being formed by the insertion of the electromagnetic shielding film 110, the flat center conductor 84 is formed with a gap formed between the respective measuring jigs 83.

In the KEC method, first, the signal output from the spectrum analyzer 91 is input to the measurement jig 83 on the transmission side via the attenuator 92. The signal is measured by the spectrum analyzer 91 after amplifying the signal through the attenuator 93 by the attenuator 93 on the receiving side of the measuring jig 83. And the spectrum analyzer 91 makes the electromagnetic wave shielding film 110 the electromagnetic wave shielding effect measuring apparatus 80 on the basis of the state which does not install the electromagnetic wave shielding film 110 in the electromagnetic wave shielding effect measuring apparatus 80. Output the attenuation when

The electromagnetic wave shielding film of this invention is 85 dB or more in the electromagnetic shielding characteristic in 200 MHz measured using such an apparatus.

It is preferable that the electromagnetic wave shielding film of this invention does not generate | occur | produce in the following interlayer peeling evaluation.

Interlayer peeling evaluation: The electromagnetic wave shielding film is affixed on a printed wiring board by hot press, the obtained shielded printed wiring board is heated at 265 degreeC, it cools to room temperature after that, and this heating and cooling are performed 5 times in total, and the said It is visually observed whether expansion is occurring in the electromagnetic shielding film.

If the electromagnetic wave shielding film of this invention has such a characteristic, the interlayer adhesion between a shielding layer and a conductive adhesive layer is hard to be destroyed.

In the electromagnetic wave shielding film of this invention, it is preferable that the opening area and opening pitch of the said opening part satisfy | fill the relationship of following formula (1).

y≤0.135x... (One)

[In Formula (1), y represents the square root of an opening area (micrometer ² ), and x represents an opening pitch (micrometer). "

When the opening area and the opening pitch of the opening satisfy the above formula (1), the electromagnetic wave shielding of the electromagnetic shielding film at 200 MHz measured by the KEC method and the evaluation in the MIT anti-fatigue test specified in JIS P8115: 2001. The characteristic becomes good.

In the electromagnetic wave shielding film of this invention, it is preferable that the opening area of the said opening part is 70-71000 micrometer <^2> , and the opening ratio of the said opening part is 0.05 to 3.6%.

If the opening area and the opening ratio of the opening formed in the shielding layer are within the above ranges, the bending resistance is sufficient, and it is possible to prevent the volatile component from accumulating between the shielding layer and the conductive adhesive layer.

If the opening area of the opening is less than 70 µm ² , the opening is too narrow, and the volatile components are less likely to pass through the shielding layer. As a result, a volatile component accumulates easily between a shielding layer and a conductive adhesive layer. Therefore, when manufacturing a shielding printed wiring board using the said electromagnetic wave shielding film, the adhesiveness between layers of a shielding layer and a conductive adhesive layer becomes easy to be destroyed. As a result, the shielding property is lowered.

When the opening area of the opening portion exceeds 71000 µm ² , the opening portion is too wide, the shielding layer is weakened, and the bending resistance decreases.

When the opening ratio of the opening portion is less than 0.05%, the ratio of the opening portion is too small, and the volatile component becomes difficult to pass through the shielding layer. As a result, a volatile component accumulates easily between a shielding layer and a conductive adhesive layer.

When the opening ratio of the opening portion exceeds 3.6%, the ratio of the opening portion is too large, the shielding layer is weakened, and the bending resistance is lowered.

In addition, in this specification, an "opening ratio" means the total opening area of several opening part with respect to the area of the whole main surface of a shielding layer.

In the electromagnetic wave shielding film of this invention, it is preferable that the opening pitch of the said opening part is 10-10000 micrometers.

When the opening pitch of the opening is less than 10 µm, the proportion of the opening increases in the entire shielding layer. As a result, the shielding layer becomes weak and the bending resistance falls.

When the opening pitch of the opening portion exceeds 10000 µm, the proportion of the opening portion in the entire shielding layer decreases. As a result, the volatile component hardly passes through the shielding layer, and the volatile component easily accumulates between the shielding layer and the conductive adhesive layer.

In addition, in this specification, an "opening pitch of an opening part" means the distance between the centers of adjacent opening parts.

In the electromagnetic wave shielding film of this invention, it is preferable that the thickness of the said shielding layer is 0.5 micrometer or more.

If the thickness of a shielding layer is less than 0.5 micrometer, since a shielding layer is too thin, a shielding characteristic will become low.

In the electromagnetic wave shielding film of this invention, it is preferable that the said shielding layer contains a copper layer.

Copper is a material suitable for a shielding layer from the viewpoint of conductivity and economy.

In the electromagnetic wave shielding film of this invention, it is preferable that the said shielding layer further contains a silver layer, the said silver layer is arrange | positioned at the said insulating layer side, and the said copper layer is arrange | positioned at the said conductive adhesive bond layer side.

The electromagnetic wave shielding film of such a structure can be easily manufactured by apply | coating silver paste so that an opening part may be formed in an insulating layer, making it a silver layer, and plating copper on a silver layer.

It is preferable that the electromagnetic wave shielding film of this invention is for flexible printed wiring boards.

As for the electromagnetic wave shielding film of this invention, when a shielding printed wiring board is manufactured as mentioned above, a volatile component is hard to accumulate between a shielding layer and a conductive adhesive layer. Moreover, the electromagnetic wave shielding film of this invention has sufficient bending resistance. Therefore, even if the electromagnetic wave shielding film of this invention is used for a flexible printed wiring board and bent repeatedly, it is hard to be damaged.

Therefore, the electromagnetic wave shielding film of this invention can be used suitably as an electromagnetic wave shielding film for flexible printed wiring boards.

The shielding printed wiring board of this invention is a shielding print containing the base member in which the printed circuit was formed, the printed wiring board which has the insulation film provided on the said base member so that the said printed circuit might be covered, and the electromagnetic wave shielding film provided on the said printed wiring board. As a wiring board, the said electromagnetic wave shielding film is an electromagnetic wave shielding film of the said invention, It is characterized by the above-mentioned.

Moreover, in the shielded printed wiring board of this invention, it is preferable that the said printed wiring board is a flexible printed wiring board.

The shielding printed wiring board of this invention has the electromagnetic wave shielding film of this invention which has sufficient bending resistance. Therefore, the shielding printed wiring board of this invention also has sufficient bending resistance.

The electronic device of the present invention is characterized in that the shielded printed wiring board of the present invention is assembled in a bent state.

As mentioned above, the shielding printed wiring board of this invention has sufficient bending resistance. Therefore, even if assembled to the electronic device in a bent state, it is difficult to be damaged. Therefore, the electronic device of this invention can narrow the space for arrange | positioning a shielded printed wiring board.

Therefore, the electronic device of the present invention can be made thin.

In the electromagnetic shielding film of the present invention, a plurality of openings are formed in the shielding layer, and in the MIT anti-fatigue test specified in JIS P8115: 2001, disconnection does not occur at 600 times, and 200 MHz was measured by the KEC method. The electromagnetic wave shielding characteristic of the said electromagnetic wave shielding film in is 85 dB or more.

Therefore, the shielding film of the present invention has high bending resistance and shielding properties.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows typically the structure of the system used by KEC method.
FIG. 2: is sectional drawing which shows an example of the electromagnetic wave shielding film of this invention typically.
3: (a) and FIG. 3 (b) are schematic diagrams which show the case where a shielding printed wiring board is manufactured using the electromagnetic wave shielding film in which the opening part is not formed in the shielding layer.
FIG. 4: (a)-FIG. 4 (c) is a top view which shows typically an example of the arrangement pattern of the opening part in the shielding layer which comprises the electromagnetic wave shielding film of this invention.
FIG. 5: is sectional drawing which shows typically an example of the electromagnetic wave shielding film of this invention in which a shielding layer consists of a copper layer and a silver layer. FIG.
FIG. 6: (a)-FIG. 6 (c) are process drawing which shows an example of the manufacturing method of the electromagnetic wave shielding film of this invention typically in order.
7 is a flowchart schematically showing an example of an insulating layer preparation step in the method for producing an electromagnetic wave shielding film of the present invention.
8 is a flowchart schematically showing an example of a silver paste printing step in the method for producing an electromagnetic wave shielding film of the present invention.
9 is a flowchart schematically showing an example of a silver paste printing step in the method for producing an electromagnetic wave shielding film of the present invention.
10 is a flowchart schematically showing an example of a silver paste printing step in the method for producing an electromagnetic wave shielding film of the present invention.
FIG. 11: (a) and FIG. 11 (b) are process drawing which shows an example of the copper plating process in the manufacturing method of the electromagnetic wave shielding film of this invention.
FIG. 12: (a) and FIG. 12 (b) are process drawing which shows an example of the conductive adhesive bond layer formation process in the manufacturing method of the electromagnetic wave shielding film of this invention.
It is a scatter diagram of the electromagnetic wave shielding film which makes a vertical axis the square root of an opening area, and makes the horizontal axis an opening pitch, and is a figure which shows the interlayer peeling evaluation of an electromagnetic wave shielding film.
Fig. 14 is a scatter diagram of an electromagnetic shielding film having a vertical axis as a square root of an opening area and a horizontal axis as an opening pitch, and illustrating evaluation of electromagnetic shielding characteristics of the electromagnetic shielding film.
Fig. 15 is a scatter diagram of an electromagnetic shielding film having the vertical axis as the square root of the opening area and the horizontal axis as the opening pitch, and showing a comprehensive evaluation of the interlayer peeling evaluation and the electromagnetic shielding characteristics of the electromagnetic shielding film.
It is a scatter diagram of the electromagnetic wave shielding film which makes a vertical axis the square root of an opening area, and makes the horizontal axis an opening pitch, and is a figure which shows the interlayer peeling evaluation of an electromagnetic wave shielding film.
Fig. 17 is a scatter diagram of an electromagnetic shielding film having the vertical axis as the square root of the opening area and the horizontal axis as the opening pitch, showing the evaluation of the bending resistance of the electromagnetic wave shielding film, the evaluation of the electromagnetic wave shielding properties, and the interlayer peeling evaluation. It is a drawing.

EMBODIMENT OF THE INVENTION Hereinafter, the electromagnetic wave shielding film of this invention is demonstrated concretely. However, this invention is not limited to the following embodiment, It can change suitably and apply in the range which does not change the summary of this invention.

It is sectional drawing which shows an example of the electromagnetic wave shielding film of this invention typically.

As shown in FIG. 2, the electromagnetic wave shielding film 10 includes a conductive adhesive layer 20, a shielding layer 30 stacked on the conductive adhesive layer 20, and an insulating layer 40 stacked on the shielding layer 30. )

In addition, a plurality of openings 50 are formed in the shielding layer 30.

(Conductive adhesive layer)

In the electromagnetic wave shielding film 10, the conductive adhesive layer 20 may be comprised with what kind of material, as long as it has electroconductivity and can function as an adhesive agent.

For example, the conductive adhesive layer 20 may be composed of conductive particles and an adhesive resin composition.

Although it does not specifically limit as electroconductive particle, Metal microparticles | fine-particles, a carbon nanotube, carbon fiber, a metal fiber, etc. may be sufficient.

In the case where the conductive particles are metal fine particles, the metal fine particles are not particularly limited, but silver powder, copper powder, nickel powder, solder powder, aluminum powder and copper powder may be coated with silver coated copper powder, polymer fine particles or glass beads. Fine particles coated with a metal may be used.

In these, it is preferable from a viewpoint of economics that it is a low cost copper powder or silver-coated copper powder.

Although the average particle diameter of electroconductive particle is not specifically limited, It is preferable that it is 0.5-15.0 micrometers. If the average particle diameter of electroconductive particle is 0.5 micrometer or more, the electroconductivity of a conductive adhesive layer will become favorable. If the average particle diameter of electroconductive particle is 15.0 micrometers or less, a conductive adhesive layer can be made thin.

Although the shape of electroconductive particle is not specifically limited, It can select suitably from a spherical form, a flat form, a scaly form, a dendrite form, a rod form, a fibrous form, etc.

Although it does not specifically limit as a material of an adhesive resin composition, A styrene resin composition, a vinyl acetate resin composition, a polyester resin composition, a polyethylene resin composition, a polypropylene resin composition, an imide resin composition, an amide resin composition, Thermosetting resin compositions, such as thermoplastic resin compositions, such as an acrylic resin composition, a phenolic resin composition, an epoxy resin composition, a urethane resin composition, a melamine resin composition, an alkyd resin composition, etc. can be used.

The material of adhesive resin composition may be single 1 type, or 2 or more types of combinations may be sufficient as them.

If necessary, the conductive adhesive layer 20 may include 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, a viscosity regulator, and the like.

Although the compounding quantity of the electroconductive particle in the electroconductive adhesive bond layer 20 is not specifically limited, It is preferable that it is 15-80 mass%, and it is more preferable that it is 15-60 mass%.

If it is the said range, the adhesiveness to a printed wiring board of a conductive adhesive layer will improve.

Although the thickness of the conductive adhesive layer 20 is not specifically limited, Although it can set suitably as needed, it is preferable that it is 0.5-20.0 micrometers.

If the thickness of a conductive adhesive layer is less than 0.5 micrometer, favorable electroconductivity will become difficult to be obtained. When the thickness of a conductive adhesive layer exceeds 20.0 micrometers, the thickness of the whole electromagnetic wave shielding film will become thick and handling becomes difficult.

In addition, it is preferable that the conductive adhesive layer 20 has anisotropic conductivity.

When the conductive adhesive layer 20 has anisotropic conductivity, the transmission characteristic of the high frequency signal transmitted by the signal circuit of a printed wiring board improves compared with the case of having isotropic conductivity.

(Insulation layer)

In the electromagnetic wave shielding film 10, although the insulating layer 40 has sufficient insulation and can protect the conductive adhesive layer 20 and the shielding layer 30, it will not specifically limit, For example, a thermoplastic resin composition and a thermosetting property It is preferable that it is comprised from a resin composition, an active energy ray curable composition, etc.

Although it does not specifically limit as said thermoplastic resin composition, A styrene resin composition, a vinyl acetate resin composition, a polyester resin composition, a polyethylene resin composition, a polypropylene resin composition, an imide resin composition, an acrylic resin composition etc. are mentioned. have.

Although it does not specifically limit as said thermosetting resin composition, A phenol resin composition, an epoxy resin composition, a urethane resin composition, a melamine resin composition, an alkyd resin composition etc. are mentioned.

Although it does not specifically limit as said active energy ray curable composition, For example, the polymeric compound etc. which have at least two (meth) acryloyloxy group in a molecule | numerator are mentioned.

The insulating layer 40 may be comprised with 1 type of independent material, and may be comprised with 2 or more types of material.

As necessary, the insulating layer 40 may contain 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, a viscosity regulator, an antiblocking agent, and the like.

Although the thickness of the insulating layer 40 is not specifically limited, Although it can set suitably as needed, it is preferable that it is 1-15 micrometers, and it is more preferable that it is 3-10 micrometers.

If the thickness of the insulating layer 40 is less than 1 micrometer, since it is too thin, it will become difficult to fully protect the conductive adhesive layer 20 and the shielding layer 30. FIG.

When the thickness of the insulating layer 40 exceeds 15 micrometers, since the thickness is too thick, the electromagnetic wave shielding film 10 will become difficult to bend and the insulating layer 40 itself will become easy to be damaged. Therefore, it becomes difficult to apply it to a member for which bending resistance is required.

(Shielding layer)

Before explaining the shielding layer of the electromagnetic wave shielding film of this invention, the case where a shielding printed wiring board is manufactured using the electromagnetic shielding film in which the opening part is not formed in a shielding layer is demonstrated using drawing.

FIG.3 (a) and FIG.3 (b) is a schematic diagram which shows typically the case where a shielding printed wiring board is manufactured using the electromagnetic wave shielding film in which the opening part is not formed in the shielding layer.

As shown in Fig. 3A, when the shielded printed wiring board is manufactured, the shielded printed wiring board on which the electromagnetic shielding film 510 is disposed is heated by a hot press or solder reflow.

By the heating, the volatile component 560 is generated from the conductive adhesive layer 520 of the electromagnetic wave shielding film 510, the insulating film of the printed wiring board, the base film, and the like.

When rapid heating is performed in such a state, as shown in FIG. 3 (b), the shielding layer 530 and the conductive adhesive layer are formed by the volatile components accumulated between the shielding layer 530 and the conductive adhesive layer 520. Interlayer adhesion of 520 may be broken.

However, in the electromagnetic wave shielding film 10 shown in FIG. 2, the some opening part 50 is formed in the shielding layer 30.

Therefore, when manufacturing a shielding printed wiring board using the electromagnetic wave shielding film 10, even if a volatile component generate | occur | produces between the shielding layer 30 and the conductive adhesive layer 20 by heating, the volatile component will not be shielded. It can pass through the opening 50 of.

Therefore, the volatile component becomes difficult to accumulate between the shielding layer 30 and the conductive adhesive layer 20. As a result, breakage of interlayer adhesion can be prevented.

Therefore, the electromagnetic wave shielding film 10 does not generate | occur | produce in the said interlayer peeling evaluation, and can make an electromagnetic wave shielding characteristic in 200 MHz measured by the said KEC method to 85 dB or more.

In the electromagnetic wave shielding film of the present invention, the electromagnetic wave shielding film of the present invention is not disconnected at 600 bending times in the MIT breakdown fatigue test specified in JIS P8115: 2001, and is disconnected at 2000 bending times. It is preferable that this does not occur.

When the electromagnetic wave shielding film of this invention has high bending resistance as mentioned above, even if the electromagnetic wave shielding film of this invention is used for a flexible printed wiring board etc., disconnection does not occur easily.

In the electromagnetic wave shielding film 10, it is preferable that the opening area of the opening part 50 is 70-71000 micrometer <^2> , and it is preferable that the opening ratio of the opening part 50 is 0.05 to 3.6%.

The opening area of the opening 50 is more preferably ² and 70~32000㎛, 70~10000㎛ ² is still more preferable, and further more preferably 80~8000㎛ ^2.

Moreover, as for the opening ratio of the opening part 50, it is more preferable that it is 0.1 to 3.6%.

If the opening area and the opening ratio of the opening portion 50 formed in the shielding layer 30 are within the above ranges, the bending resistance is sufficient, and volatile components can be prevented from accumulating between the shielding layer 30 and the conductive adhesive layer 20. have.

Moreover, the electromagnetic wave shielding characteristic of the electromagnetic wave shielding film in 200 MHz measured by the KEC method becomes favorable.

If the opening area of the opening of the shielding layer is less than 70 µm ² , the opening is too narrow, and the volatile component becomes difficult to pass through the shielding layer. As a result, a volatile component accumulates easily between a shielding layer and a conductive adhesive layer.

When the opening area of the opening of the shielding layer exceeds 71000 µm ² , the opening is too wide, the shielding layer is weakened, and the bending resistance is lowered.

When the opening ratio of the opening of the shielding layer is less than 0.05%, the ratio of the opening is too small, and the volatile components hardly pass through the shielding layer. As a result, a volatile component accumulates easily between a shielding layer and a conductive adhesive layer.

When the opening ratio of the opening of the shielding layer exceeds 3.6%, the ratio of the opening is too large, the shielding layer is weakened, and the bending resistance is lowered.

In the electromagnetic wave shielding film 10, the shape of the opening part 50 is not specifically limited, A round shape, an ellipse, a racetrack shape, a triangle, a rectangle, a pentagon, a hexagon, an octagon, a star, etc. may be sufficient.

In these, it is preferable that it is circular from the ease of formation of the opening part 50.

In addition, the shape of the some opening part 50 may be single 1 type, and multiple types may be combined.

In the electromagnetic wave shielding film 10, it is preferable that the opening pitch of the opening part 50 is 10-10000 micrometers, It is more preferable that it is 25-2000 micrometers, It is further more preferable that it is 250-2000 micrometers.

When the opening pitch of the opening is less than 10 µm, the proportion of the opening increases in the entire shielding layer. As a result, the shielding layer becomes weak and the bending resistance falls.

When the opening pitch of the opening portion exceeds 10000 µm, the proportion of the opening portion in the entire shielding layer decreases. As a result, the volatile component hardly passes through the shielding layer, and the volatile component easily accumulates between the shielding layer and the conductive adhesive layer. As a result, the interlayer adhesion between the shielding layer and the conductive adhesive layer tends to be broken, and the shielding characteristics also tend to be lowered.

In the electromagnetic wave shielding film 10, it is preferable that the opening area and opening pitch of the opening part 50 satisfy | fill the relationship of following formula (1).

y≤0.135x... (One)

[In Formula (1), y represents the square root of an opening area (micrometer ² ), and x represents an opening pitch (micrometer). "

In the electromagnetic wave shielding film 10, when the opening area and opening pitch of an opening satisfy said formula (1), it measured by the evaluation in the MIT anti-fatigue test prescribed by JIS P8115: 2001, and the KEC method. The electromagnetic wave shielding characteristic of the electromagnetic wave shielding film in 200 MHz becomes favorable.

In the electromagnetic wave shielding film 10, although the arrangement pattern of the opening part 50 is not specifically limited, For example, the arrangement pattern shown below may be sufficient.

4 (a) to 4 (c) are plan views schematically showing an example of the arrangement pattern of the openings in the shielding layer constituting the electromagnetic wave shielding film of the present invention.

As shown in Fig. 4A, the arrangement pattern of the openings 50 is an arrangement pattern in which the centers of the openings 50 are located at the vertices of the equilateral triangles in a plane in which the equilateral triangles are arranged vertically and horizontally. It may be.

In addition, as shown in Fig. 4B, the arrangement pattern of the openings 50 is arranged in such a manner that the center of the openings 50 is located at the vertices of the square in a plane in which the squares are arranged continuously in the vertical and horizontal direction. It may be a pattern.

In addition, as shown in Fig. 4C, the arrangement pattern of the openings 50 is an arrangement in which the center of the openings 50 is located at the vertices of the regular hexagon in a plane in which the regular hexagons are arranged vertically and horizontally. It may be a pattern.

In the electromagnetic wave shielding film 10, it is preferable that the thickness of the shielding layer 30 is 0.5 micrometer or more, and it is more preferable that it is 1.0 micrometer or more. In addition, it is preferable that the thickness of the shielding layer 30 is 10 micrometers or less.

If the thickness of a shielding layer is less than 0.5 micrometer, since a shielding layer is too thin, a shielding characteristic will become low.

Moreover, when the thickness of the shielding layer 30 is 1.0 micrometer or more, the transmission characteristic will become favorable in the signal transmission system which transmits the high frequency signal of 0.01-10 GHz.

And when an opening part is not formed in a shielding layer, when a shielding layer becomes thick, when an shielding printed wiring board is manufactured, breakage of the interlayer adhesion between a shielding layer and a conductive adhesive layer will arise easily. In particular, when the thickness of the shielding layer 30 exceeds 1.0 µm, breakage of interlayer adhesion occurs remarkably. However, in the electromagnetic wave shielding film 10, since the opening part 50 is formed in the shielding layer 30, interlayer adhesion between the shielding layer 30 and the conductive adhesive layer 20 can be prevented from being destroyed.

It is preferable that the electromagnetic wave shielding film of this invention is used for the signal transmission system which transmits the signal of a frequency of 0.01-10 GHz.

In the electromagnetic wave shielding film of this invention, as long as a shielding layer has electromagnetic wave shielding property, what kind of material may be sufficient and it may be a metal layer, for example.

The shielding layer may include a layer made of a material such as gold, silver, copper, aluminum, nickel, tin, palladium, chromium, titanium, zinc or the like, and preferably includes a copper layer.

Copper is a suitable material for a shielding layer from the viewpoint of conductivity and economy.

The shielding layer may include a layer made of an alloy of the metal.

In the shielding layer, a plurality of metal layers may be laminated.

In particular, the shielding layer preferably includes a copper layer and a silver layer.

The case where a shielding layer contains a copper layer and a silver layer is demonstrated using drawing.

It is sectional drawing which shows typically an example of the electromagnetic wave shielding film of this invention in which a shielding layer consists of a copper layer and a silver layer.

The electromagnetic wave shielding film 110 shown in FIG. 5 includes a conductive adhesive layer 120, a shielding layer 130 stacked on the conductive adhesive layer 120, and an insulating layer 140 stacked on the shielding layer 130. .

In addition, the shielding layer 130 is composed of a copper layer 132 and a silver layer 131, the silver layer 131 is disposed on the insulating layer 140 side, the copper layer 132 is a conductive adhesive layer 120 It is arranged on the side.

The electromagnetic wave shielding film 110 of such a structure can be easily manufactured by apply | coating silver paste so that the opening part 150 may be formed in the insulating layer 140, and making it a silver layer, and plating copper on a silver layer.

(Other composition)

In the electromagnetic wave shielding film of this invention, the anchor coat layer may be formed between the insulating layer and the shielding layer.

As the material of the anchor coat layer, a core-shell composite resin having a urethane resin, an acrylic resin, and a urethane resin as a shell and an acrylic resin as a core, an epoxy resin, an imide resin, an amide resin, a melamine resin, and a phenol resin And block isocyanates obtained by reacting urea formaldehyde resins and polyisocyanates with blocking agents such as phenols, polyvinyl alcohols, and polyvinyl prolidones.

Moreover, in the electromagnetic wave shielding film of this invention, you may have a support film on the insulating layer side, and you may have a peelable film on the conductive adhesive bond layer side. When the electromagnetic wave shielding film has a support film or a peelable film, the electromagnetic wave shielding of the present invention is carried out in transporting the electromagnetic wave shielding film of the present invention or in manufacturing a shielding printed wiring board using the electromagnetic wave shielding film of the present invention. The film becomes easy to handle.

Moreover, when arrange | positioning the electromagnetic wave shielding film of this invention to a shielding printed wiring board etc., such a support film and a peelable film will peel.

The electromagnetic wave shielding film of the present invention may be used for any purpose as long as it is intended to block electromagnetic waves.

In particular, it is preferable to use the electromagnetic wave shielding film of this invention for a printed wiring board, especially a flexible printed wiring board.

As mentioned above, the electromagnetic wave shielding film of this invention hardly collects a volatile component between a shielding layer and a conductive adhesive layer when manufacturing a shielding printed wiring board. Moreover, the electromagnetic wave shielding film of this invention has sufficient bending resistance. Therefore, even if the electromagnetic wave shielding film of this invention is used for a flexible printed wiring board and bent repeatedly, it is hard to be damaged.

Therefore, the electromagnetic wave shielding film of this invention can be used suitably as an electromagnetic wave shielding film for flexible printed wiring boards.

Thus, the shielding printed wiring board which has the electromagnetic wave shielding film of this invention is a shielding printed wiring board of this invention.

That is, the shielding printed wiring board of this invention is a shielding print which has the base member in which the printed circuit was formed, the printed wiring board which has the insulation film provided on the said base member so that the said printed circuit might be covered, and the electromagnetic wave shielding film provided on the said printed wiring board. As a wiring board, the said electromagnetic wave shielding film is an electromagnetic wave shielding film of the said invention, It is characterized by the above-mentioned.

Moreover, it is preferable that the said printed wiring board is a flexible printed wiring board.

The shielding printed wiring board of this invention has the electromagnetic wave shielding film of this invention which has sufficient bending resistance. Therefore, the shielding printed wiring board of this invention also has sufficient bending resistance.

The shielded printed wiring board of the present invention is used by being assembled to an electronic device.

In particular, the electronic device assembled with the shielded printed wiring board of the said invention is bent is the electronic device of this invention.

As mentioned above, the shielding printed wiring board of this invention has sufficient bending resistance. Therefore, even if assembled to the electronic device in a bent state, it is difficult to be damaged. Therefore, the electronic device of this invention can narrow the space for arrange | positioning a shielded printed wiring board.

Therefore, the electronic device of the present invention can be made thin.

(Method for producing electromagnetic shielding film)

Next, the manufacturing method of the electromagnetic wave shielding film of this invention is demonstrated. And the electromagnetic wave shielding film of this invention is not limited to what was manufactured by the method shown below.

First, an example of the manufacturing method of the electromagnetic wave shielding film 10 which is an example of the electromagnetic wave shielding film of this invention is demonstrated.

The method of manufacturing the electromagnetic wave shielding film 10 includes (1) a shielding layer forming step, (2) an insulating layer forming step, and (3) a conductive adhesive layer forming step.

These processes are explained in full detail below using drawing.

FIG.6 (a)-FIG.6 (c) are process drawing which shows an example of the manufacturing method of the electromagnetic wave shielding film of this invention typically in order.

(1) shielding layer forming process

First, as shown to Fig.6 (a), the sheet | seat 35 which has electromagnetic wave shielding property is prepared, and the opening part 50 is formed in the sheet | seat 35, and the shielding layer 30 is produced.

At this time, it is preferable to form an opening so that the opening area and opening pitch of the opening part 50 satisfy | fill the relationship of following formula (1).

y≤0.135x... (One)

[In Formula (1), y represents the square root of an opening area (micrometer ² ), and x represents an opening pitch (micrometer). "

The opening 50 can be formed by punching, laser irradiation, or the like.

In addition, when the sheet | seat 35 consists of etching material, such as copper, even if it forms the resist of the pattern like the opening part 50 is formed in the surface of the sheet | seat 35, even if the opening part 50 is formed by etching, do.

In addition, you may print the electrically conductive paste and the paste which functions as a plating catalyst on the surface of the sheet | seat 35. FIG. In this printing, you may form the opening part 50 by printing in a predetermined pattern.

When printing the paste which functions as the said plating catalyst, it is preferable to form a shielding layer by printing a paste and forming the opening part 50, and then forming a metal film by an electroless plating method or an electroplating method.

As the paste that functions as the plating catalyst, a fluid containing a metal made of nickel, copper, chromium, zinc, gold, silver, aluminum, tin, cobalt, palladium, lead, platinum, cadmium, rhodium, or the like can be used.

(2) insulation layer forming process

Next, as shown in FIG. 6B, the insulating layer resin composition 45 is coated and cured on one surface of the shielding layer 30 to form the insulating layer 40.

As a method of coating the resin composition for insulating layers, a conventionally well-known coating method, for example, a gravure coat method, a kiss coat method, a die coat method, a lip coat method, a comma coat method, a blade coat method, a roll coat method, a knife coat method, A spray coat system, a bar coat system, a spin coat system, a dip coat system, etc. are mentioned.

As a method of hardening the resin composition for insulating layers, the conventionally well-known various methods can be employ | adopted according to the kind of resin composition for insulating layers.

(3) Conductive Adhesive Layer Formation Step

Next, as shown in FIG. 6C, the conductive adhesive layer 20 is coated by coating the composition 25 for the conductive adhesive layer on a surface opposite to the surface on which the insulating layer 40 of the shielding layer 30 is formed. Form.

As a method of coating the composition 25 for conductive adhesive layers, a conventionally well-known coating method, for example, a gravure coat system, a kiss coat system, a die coat system, a lip coat system, a comma coat system, a blade coat system, a roll coat system , Knife coat method, spray coat method, bar coat method, spin coat method, deep coat method and the like.

Through the above process, the electromagnetic wave shielding film 10 which is an example of the electromagnetic wave shielding film of this invention can be manufactured.

Next, an example of the method of manufacturing the electromagnetic wave shielding film 110 which is an example of the electromagnetic wave shielding film of this invention and a shielding layer consists of a copper layer and a silver layer is demonstrated.

The method of manufacturing the electromagnetic wave shielding film 110 includes (1) an insulating layer preparation step, (2) silver paste printing step, (3) copper plating step, and (4) conductive adhesive layer forming step.

These processes are explained in full detail below using FIGS.

(1) insulating layer preparation process

FIG. 7: is a process figure which shows typically an example of the insulating layer preparation process in the manufacturing method of the electromagnetic wave shielding film of this invention.

First, as shown in FIG. 7, the insulating layer 140 is prepared.

The insulating layer 140 can be prepared by a conventional method.

(2) Printing process of fluid containing metal as plating catalyst (silver paste printing process)

Next, silver paste is printed on one main surface of the insulating layer as the plating catalyst. At this time, an opening is formed in the silver paste.

As a method of printing the silver paste, a method of printing intaglio printing such as gravure printing or iron plate printing such as flexographic printing, a method of screen printing, transferring a pattern formed by intaglio, iron plate, screen, etc. The method by the offset printing performed, the method by the inkjet printing which a plate is unnecessary, etc. are mentioned.

The method of printing a silver paste by gravure printing is demonstrated below.

8-10 is process drawing which shows typically an example of the silver paste printing process in the manufacturing method of the electromagnetic wave shielding film of this invention.

First, as shown in FIG. 8, the roll-shaped plate | board board 70 in which the some columnar protrusion part 72 was formed in the surface is prepared. In addition, the surface of the plate | board plate in which the protrusion part 72 is not formed is the protrusion part non-formation area 71.

Next, as shown in FIG. 9, the silver paste 133 is taken into the protrusion non-forming region 71. At this time, the silver paste 133 is prevented from being applied to the upper surface 73 of the protrusion 72.

And as shown in FIG. 10, the insulating layer 140 is made to pass between the impression cylinder 75 and the plate | board 70 in which the silver paste 133 was taken in, and the insulator layer 140 of FIG. The silver paste 133 is printed on one main surface.

In the printing, the silver paste 133 is not printed on the portion of the insulating layer 140 that the protrusions 72 reach, and may be the opening 150.

The silver paste 133 printed on the insulating layer 140 becomes the silver layer 131.

The silver paste 133 may contain various additives, such as a dispersing agent, a thickener, a leveling agent, and an antifoamer, in addition to the silver paste 133.

The shape of silver particle is not specifically limited, The material of arbitrary shapes, such as spherical shape, a flake shape, resin type, needle shape, fibrous form, can be used.

When the said silver particle is a particulate form, it is preferable that it is nano size. Specifically, silver particles having an average particle diameter in the range of 1 to 100 nm are preferable, and silver particles having a range of 1 to 50 nm are more preferable.

In addition, in this specification, an "average particle diameter" means the volume average value which diluted silver particle with the solvent for dispersion, and measured by the dynamic light scattering method.

For this measurement, "nano track UPA-150" manufactured by MicroTrack Corporation can be used.

Moreover, it is preferable that the thickness of the silver layer formed of the silver paste to print is 5-200 nm.

(3) copper plating process

FIG.11 (a) and FIG.11 (b) are process drawing which shows typically an example of the copper plating process in the manufacturing method of the electromagnetic wave shielding film of this invention.

Next, as shown in FIGS. 11A and 11B, the copper layer 132 is formed on the silver layer 131 by plating copper on the silver layer 131.

The plating method of copper is not specifically limited, Conventional electroless plating and electrolytic plating can be used.

When plating copper by electroless plating, it is preferable to use what contains a solvent, such as a copper sulfate, a reducing agent, and an aqueous medium, an organic solvent, as a plating liquid.

In the case of plating copper by the electrolytic plating method, by using copper sulfate, sulfuric acid, and an aqueous medium containing a plating solution as the plating solution, by controlling the plating treatment time, the current density, the amount of the additive used for plating, etc., so as to have a desired copper thickness. It is preferable to adjust.

It is preferable that the thickness of copper to plate is 0.1-10 micrometers.

Through the above process, the shielding layer 130 which consists of the silver layer 131 and the copper layer 132 can be formed.

(4) Conductive Adhesive Layer Formation Step

12 (a) and 12 (b) are process diagrams schematically showing an example of a conductive adhesive layer forming step in the method for producing an electromagnetic wave shielding film of the present invention. In addition, in FIG.12 (a) and FIG.12 (b), FIG.11 (b) is reversed up and down and the process after that is shown.

Next, as shown in FIGS. 12A and 12B, the conductive adhesive layer composition 125 is coated on the copper layer 132 to form the conductive adhesive layer 120. As a method of coating the composition 125 for conductive adhesive layers, a conventionally well-known coating method, for example, a gravure coat method, a kiss coat method, a die coat method, a lip coat method, a comma coat method, a blade coat method, a roll coat method, a knife A coat method, a spray coat method, a bar coat method, a spin coat method, a dip coat method, etc. are mentioned.

After passing the above process, the electromagnetic wave shielding film 110 which is an example of the electromagnetic wave shielding film of this invention can be manufactured.

EXAMPLE

The area of the opening of the shielding layer (area square root of the opening) is 79 μm ² (8.89 μm), 1963 μm ² (44.30 μm), 4418 μm ² (66.47 μm), 7854 μm ² (88.62 μm), 12272 μm ² (110.78 ^{㎛), 17671㎛ 2 (132.93㎛)} , 31416㎛ 2 (177.25㎛), 49087㎛ 2 (221.56㎛) or 70686㎛ ² (265.87㎛), and the opening pitch 10㎛, 50㎛, 100㎛, 200㎛ 126 kinds of electromagnetic wave shielding films in total, 500 µm, 750 µm, 1000 µm, 1500 µm, 2000 µm, 3000 µm, 4000 µm, 5000 µm, 7500 µm or 10000 µm, were produced by the following method.

And the shape of the opening part of a shielding layer is circular.

Preparation Example 1 Preparation Example of Silver Paste

A silver paste having a silver concentration of 15% by mass was obtained by dispersing silver particles having an average particle diameter of 30 nm in a mixed solvent of 35 parts by mass of ethanol and 65 parts by mass of ion-exchanged water using a polyethyleneimine compound as a dispersant.

(Manufacture of electromagnetic wave shielding film)

(1) insulating layer preparation process

An insulating layer made of an epoxy resin having a thickness of 5 μm was prepared.

(2) silver paste printing process

Next, the silver paste was printed and the silver layer was formed so that a some opening part may be formed in one main surface of the insulating layer using the roll-shaped copper plate by the method as shown to FIGS. 8-10.

The combination of the opening area and the opening pitch of the opening is as described above.

In addition, the thickness of the silver layer was 50 nm.

As the silver paste, the silver paste obtained in Preparation Example 1 was used.

In addition, the shape of the opening part was circular, and the arrangement pattern of the opening part was made into the arrangement pattern in which the center of each opening part is located in the vertex of an equilateral triangle in the plane which arranged the regular triangle vertically and horizontally.

(3) copper plating process

Next, the insulating layer after silver paste printing was immersed for 20 minutes in an electroless copper plating solution ("ARG Copper" by Okuno Seiyaku Co., Ltd., pH 12.5) at 55 degreeC, and an electroless copper plating film (thickness 0.5 on a silver layer) Μm) was formed.

Subsequently, the surface of the electroless copper plating film obtained above is provided on the cathode, phosphorus containing copper is provided on the anode, and electroplating is carried out for 30 minutes at a current density of 2.5 A / dm 2 using an electroplating solution containing copper sulfate. The copper plating layer whose total thickness is 1 micrometer was laminated | stacked on the silver layer. As the electroplating solution, a solution of 70 g / liter of copper sulfate, 200 g / liter of sulfuric acid, 50 mg / liter of chlorine ions, and 5 g / liter of TOFLITINA SF (gloss produced by Okuno Seiyaku Kogyo Co., Ltd.) was used.

(4) Conductive Adhesive Layer Formation Step

The conductive adhesive layer which added 20 mass% of Ag coating Cu powder to the phosphorus containing epoxy resin was coated so that thickness might be set to 15 micrometers on the copper layer, and the electromagnetic wave shielding film was produced.

As the coating method, a lip coat method was used.

(Evaluation of bending resistance)

Each electromagnetic wave shielding film was evaluated by the following method.

Each electromagnetic wave shielding film is attached to both sides of a 50-micrometer-thick polyimide film by heat press, cut into the size of length X width = 130 mm x 15 mm, and it is set as a test piece, and is made by MIT anti-fatigue tester The bending resistance was measured based on the method prescribed | regulated to JIS P8115: 2001 using the K.K. Seisakusho make, No.307 MIT type anti-collision tester.

Test conditions are as follows.

Bending clamp tip R: 0.38 mm

Bending Angle: ± 135 °

Bending Speed: 175cpm

Load: 500gf

Detection method: Detects disconnection of shielding film by built-in traditional device

The results are shown in FIG.

It is a scatter diagram of the electromagnetic wave shielding film which makes a vertical axis the square root of an opening area, and makes the horizontal axis an opening pitch, and is a figure which shows the evaluation of the bending resistance of an electromagnetic wave shielding film.

In FIG. 13, the code | symbol "(circle)" shows the electromagnetic wave shielding film which a disconnection does not generate | occur | produce in 600 bending times in evaluation of bending resistance.

In FIG. 13, the code | symbol "x" shows the electromagnetic wave shielding film which the disconnection generate | occur | produced when the frequency | count of bending is less than 600 in evaluation of bending resistance.

As shown in FIG. 13, when the square root of an opening area is set to y and opening pitch is set to x, when the relationship of y and x satisfy | fills following Formula (1), the bending resistance of an electromagnetic wave shielding film will become favorable.

y≤0.135x... (One)

(Evaluation of electromagnetic shielding characteristics by KEC method)

Regarding the electromagnetic shielding characteristics of each electromagnetic shielding film, using the electromagnetic shielding effect measuring device developed at the KEC Kansai Electronics Industry Promotion Center, which is a general corporation, each electromagnetic shielding film was subjected to a temperature of 25 ° C and a relative humidity of 30 to 50%. Was cut to 15 cm on all sides, and the electromagnetic wave shielding property at 200 MHz was measured and evaluated.

The results are shown in FIG.

It is a scatter diagram of the electromagnetic wave shielding film which makes a vertical axis the square root of an opening area, and makes the horizontal axis an opening pitch, and is a figure which shows the evaluation of the electromagnetic wave shielding characteristic of an electromagnetic wave shielding film.

In FIG. 14, the code | symbol "(circle)" shows the electromagnetic wave shielding film whose electromagnetic wave shielding characteristic in 200 MHz measured by the KEC method is 85 dB or more.

In FIG. 14, the code | symbol "x" represents the electromagnetic wave shielding film whose electromagnetic shielding characteristic in 200 MHz measured by the KEC method is less than 85 dB.

As shown in Fig. 14, when the square root of the opening area is y and the opening pitch is x, the evaluation of electromagnetic shielding characteristics by the KEC method of the electromagnetic shielding film when the relationship between y and x satisfies the following formula (2): Becomes good.

y≤0.38x... (2)

(Comprehensive evaluation of evaluation of bending resistance and evaluation of electromagnetic shielding characteristics by KEC method)

It is a scatter diagram of the electromagnetic wave shielding film which makes a vertical axis the square root of an opening area, and makes the horizontal axis an opening pitch, and is a figure which shows the evaluation of the bending resistance of an electromagnetic wave shielding film, and comprehensive evaluation of an electromagnetic wave shielding characteristic.

In FIG. 15, the code | symbol "(circle)" shows the electromagnetic wave shielding film whose electromagnetic wave shielding characteristic in 200 MHz measured by the KEC method does not generate | occur | produce a disconnection at the bending frequency of 600 times in evaluation of bending resistance.

In FIG. 15, the code | symbol "x" shows the electromagnetic wave shielding film which the disconnection generate | occur | produced when the frequency | count of bending is less than 600 in evaluation of bending resistance.

The electromagnetic wave shielding film shown by the symbol "(circle)" in FIG. 15 is the electromagnetic wave shielding film which concerns on the Example of this invention, and the electromagnetic wave shielding film shown by the symbol "x" is the electromagnetic wave shielding film which concerns on the comparative example of this invention.

As shown in FIG. 15, when the square root of an opening area is set to y and opening pitch is set to x, the electromagnetic shielding film which the relationship of y and x satisfy | fills the relationship of following formula (1) is an Example of this invention. Electromagnetic wave shielding film.

y≤0.135x... (One)

(Interlayer Peeling Evaluation)

The interlayer peeling evaluation of the electromagnetic wave shielding film was performed with the following method.

First, each electromagnetic shielding film was affixed on the printed wiring board by heat press.

Subsequently, the shielded printed wiring board was allowed to stand in a clean room at 23 ° C. and 63% RH for 7 days, and then exposed to temperature conditions at the time of reflow for 30 seconds to evaluate the presence or absence of interlayer peeling. And as a temperature condition at the time of reflow, lead-free solder was assumed and the maximum temperature profile of 265 degreeC was set. In addition, the presence or absence of interlayer peeling passed the shielding printed wiring board five times through atmospheric reflow, and observed the presence or absence of expansion.

The results are shown in FIG.

It is a scatter diagram of the electromagnetic wave shielding film which makes a vertical axis the square root of an opening area, and makes a horizontal axis an opening pitch, and is a figure which shows the interlayer peeling evaluation of an electromagnetic wave shielding film.

In FIG. 16, the code | symbol "(circle)" represents the electromagnetic wave shielding film in which expansion does not generate | occur | produce in an interlayer peeling evaluation.

In FIG. 16, the code | symbol "x" represents the electromagnetic wave shielding film in which an expansion generate | occur | produces in interlayer peeling evaluation.

As shown in FIG. 16, when the square root of an opening area is set to y and opening pitch is set to x, when the relationship of y and x satisfy | fills following Formula (3), the interlayer peeling evaluation of an electromagnetic wave shielding film will become favorable.

y≥0.02x + 3... (3)

(Evaluation of bending resistance, evaluation of electromagnetic shielding characteristics by KEC method, and comprehensive evaluation of interlayer peeling evaluation)

Fig. 17 is a scatter diagram of an electromagnetic shielding film having the vertical axis as the square root of the opening area and the horizontal axis as the opening pitch, and showing the comprehensive evaluation of the evaluation of the bending resistance of the electromagnetic shielding film, the evaluation of the electromagnetic shielding properties, and the interlayer peeling evaluation. Drawing.

In FIG. 17, the symbol "(circle)" indicates that the breakage does not occur when the number of bending is 600 times in the evaluation of the bending resistance, and the electromagnetic shielding characteristic at 200 MHz measured by the KEC method is 85 dB or more, and is expanded in the interlayer peeling evaluation. The electromagnetic wave shielding film which does not generate | occur | produce this is shown.

In FIG. 17, the symbol "(circle)" shows that the breakage does not occur at 600 bending times in the evaluation of bending resistance, and the electromagnetic shielding characteristic at 200 MHz measured by the KEC method is 85 dB or more, and is expanded in the interlayer peeling evaluation. This generated electromagnetic shielding film is shown.

In FIG. 17, the code | symbol "x" shows the electromagnetic wave shielding film which the disconnection generate | occur | produced when the frequency | count of bending is less than 600 in evaluation of bending resistance.

10, 110: electromagnetic wave shielding film
20, 120: conductive adhesive layer
25, 125: composition for conductive adhesive layers
30, 130: shielding layer
40, 140: insulation layer
45: resin composition for insulating layer
50, 150 openings
70: Pandong
71: protrusion non-formation area
72: protrusion
73: upper surface of the protrusion
75: tenderness
80: electromagnetic wave shielding effect measuring device
83: Measuring Jig
84: center conductor
91: spectrum analyzer
92, 93: Attenuator
94: preamplifier
131: silver layer
132: copper layer
133: silver paste

Claims (12)

As an electromagnetic wave shielding film which consists of a conductive adhesive layer, the shielding layer laminated | stacked on the said conductive adhesive layer, and the insulating layer laminated | stacked on the said shielding layer,
A plurality of openings are formed in the shielding layer,
In the MIT anti-fatigue test specified in JIS P8115: 2001, disconnection does not occur when the number of bending is 600 times,
The electromagnetic wave shielding property of the said electromagnetic wave shielding film in 200 MHz measured by the KEC method is 85 dB or more,
Electromagnetic shielding film. The method of claim 1,
In the following delamination evaluation, no expansion occurs,
The said interlayer peeling evaluation attaches an electromagnetic wave shielding film on a printed wiring board by heat press, heats the obtained shielded printed wiring board to 265 degreeC, cools to room temperature after that, and performs the said heating and cooling 5 times in total, The electromagnetic wave shielding film which visually observes whether expansion | swelling generate | occur | produces in the said electromagnetic wave shielding film. The method according to claim 1 or 2,
The electromagnetic wave shielding film in which the opening area and opening pitch of the said opening satisfy | fill the relationship of following formula (1):
y≤0.135x... (One)
[In Formula (1), y represents the square root of an opening area (micrometer ² ), and x represents an opening pitch (micrometer). " The method according to any one of claims 1 to 3,
And the opening area of the opening 70㎛ ² ~71000㎛ ^2, also,
The electromagnetic wave shielding film of which the opening ratio of the said opening part is 0.05%-3.6%. The method according to any one of claims 1 to 4,
The electromagnetic wave shielding film of the said opening part whose opening pitch is 10 micrometers-10000 micrometers. The method according to any one of claims 1 to 5,
Electromagnetic shielding film, the thickness of the said shielding layer is 0.5 micrometer or more. The method according to any one of claims 1 to 6,
The shielding layer, electromagnetic shielding film comprising a copper layer. The method of claim 7, wherein
The shielding layer further comprises a silver layer,
The silver layer is disposed on the insulating layer side,
The said copper layer is arrange | positioned at the said conductive adhesive bond layer side. The method according to any one of claims 1 to 8,
The electromagnetic wave shielding film is an electromagnetic wave shielding film for flexible printed wiring boards. A base member on which a printed circuit is formed;
A printed wiring board having an insulating film provided on the base member so as to cover the printed circuit; And
Electromagnetic shielding film installed on the printed wiring board
As a shielded printed wiring board having
The said electromagnetic wave shielding film is an electromagnetic wave shielding film in any one of Claims 1-9.
Shielded printed wiring board. The method of claim 10,
The said printed wiring board is a flexible printed wiring board, The shielded printed wiring board. The electronic device which is assembled in the state which the shielded printed wiring board of Claim 10 or 11 was bent.

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