WO2016117719A1

WO2016117719A1 - Electromagnetic wave shielding film and manufacturing method thereof

Info

Publication number: WO2016117719A1
Application number: PCT/KR2015/000589
Authority: WO
Inventors: Yoon Hyun Kim; Seung Jin Yang; Kyu Jae Lee
Original assignee: CHANG SUNG Co Ltd
Current assignee: CHANG SUNG Co Ltd
Priority date: 2015-01-20
Filing date: 2015-01-20
Publication date: 2016-07-28
Anticipated expiration: 2017-07-20
Also published as: KR20160100815A; KR101690166B1

Abstract

Disclosed is an electromagnetic wave shielding film. The disclosed electromagnetic wave shielding film includes: an insulating layer including a binder resin containing an epoxy resin, a filler, a curing agent, a solvent, and other additives; and a conductive shielding layer including a binder resin which is the same as the binder resin of the insulating layer, copper as a conductive filler, a curing agent, and a solvent, wherein the solvent is selected from at least one group of solvents having an ester group (-COOR), solvents having a hydroxyl group (-OH), solvents having an ester group (-COOR) and a hydroxyl group (-OH), solvents having a ketone group (C=O), and solvents having an alkyl group (-R) only or a combination of two or more thereof.

Description

ELECTROMAGNETIC WAVE SHIELDING FILM AND MANUFACTURING METHOD THEREOF

The present invention relates to an electromagnetic wave shielding film and a manufacturing method thereof, and more particularly, to an electromagnetic wave shielding film and a manufacturing method of the electromagnetic wave shielding film having shielding efficiency equivalent to that of the existing product and reduced in manufacturing cost.

Along with a recent trend of miniaturization and lightness, electronic devices used for a portable mobile device, a notebook computer, a personal digital assistant (PDA), a liquid crystal display (LCD), an organic light emitting diode (OLED), a plasma display panel (PDP), etc. have been studied to increase a signal transfer speed between electronic components.

As a printed circuit board (PCB) has become a micro-circuit, damage of electromagnetic interference (EMI) caused by occurrence of electromagnetic wave noise between adjacent circuits has been on the increase.

In order to effectively shield such an electromagnetic wave, it is required to enclose the printed circuit board (PCB) by a metal film having an excellent electrical conductivity to allow the electromagnetic wave occurring between the circuits to be diminished through the metal film.

To do so, a thin metal film having an excellent conductivity is attached to the printed circuit board or a conductive paste is coated on the printed circuit board. Alternatively, a conductive adhesive film-type product in which the conductive paste is made in a film form and heated and attached to the printed circuit board has been applied.

Particularly, in the case of a multi-layer flexible printed circuit board (FPCB) such as a rigid flex board, a demand for an adhesive film-type product having excellent step-filling property and electroconductive resistance has been greatly increased.

Further, there has been increased a need for development of an electromagnetic wave shielding film having excellent step-filling property and electrical conductivity in a rigid flex-type FPCB as well as a satisfactory adhesion with respect to a substrate.

For example, as a conventional electromagnetic wave shielding and adhesive film, there is known a reinforcement-shielding film including a conductive adhesive layer and, if necessary, a shielding layer formed of a thin metal film layer on one surface of a cover film and an adhesive layer and a releasable reinforcement film laminated in sequence on the other surface (refer to Patent Literature 1).

Further, there is known a shielding film including a shielding layer having a conductive adhesive layer and/or a thin metal film and a base film formed of an aromatic polyimide resin (refer to Patent Literature 2).

Furthermore, there is known a shielding adhesive film in which a cover film is formed by coating a resin on one surface of a separate film and a shielding layer including a thin metal film layer and an adhesive layer is provided on a surface of the cover film (Patent Literature 3).

Meanwhile, an electromagnetic wave shielding film developed recently uses silver-coated copper having a high thermal conductivity to increase the shielding efficiency, but has a drawback in that expensive silver is used, resulting in an increase in shielding film manufacturing cost.

[Citation List]

[Patent Literature]

[Patent Literature 1] JP 2003-298285 A

[Patent Literature 2] JP 2004-273577 A

[Patent Literature 3] JP 2004-95566 A

The present invention provides an electromagnetic wave shielding film and a manufacturing method of the electromagnetic wave shielding film having shielding efficiency equivalent to that of the existing shielding film using silver-coated copper.

Further, the present invention provides an electromagnetic wave shielding film and a manufacturing method of the electromagnetic wave shielding film having shielding efficiency equivalent to that of the existing product and reduced in manufacturing cost.

In an exemplary embodiment, an electromagnetic wave shielding film includes: an insulating layer including 7 to 18 wt% of a binder resin containing an epoxy resin, 4.5 to 8.5 wt% of a filler, 7 to 12 wt% of a curing agent, 65 to 70 wt% of a solvent, and other additives; and a conductive shielding layer including 15 to 20 wt% of a binder resin which is the same as the binder resin of the insulating layer, 30 to 40 wt% of copper as a conductive filler, 1.5 to 2.5 wt% of a curing agent, and 35 to 45 wt% of a solvent, wherein the solvent is selected from at least one group of solvents having an ester group (-COOR), solvents having a hydroxyl group (-OH), solvents having an ester group (-COOR) and a hydroxyl group (-OH), solvents having a ketone group (C=O), and solvents having an alkyl group (-R) only or a combination of two or more thereof.

According to an exemplary embodiment, the binder resin of the insulating layer may further include a polyurethane resin.

According to an exemplary embodiment, the polyurethane resin may be added in an amount of 5 to 15 wt% with respect to 100 wt% of the insulating layer.

According to an exemplary embodiment, the curing agent of the conductive shielding layer may further include a urea resin as a curing accelerator.

According to an exemplary embodiment, the curing accelerator may be added in an amount of 1.5 to 2.5 wt% with respect to 100 wt% of the conductive shielding layer.

According to an exemplary embodiment, a releasable protective film laminated on a lower surface of the conductive layer, an upper surface of the insulating layer, or the lower surface of the conductive layer and the upper surface of the insulating layer may be further included.

In an exemplary embodiment, a manufacturing method of an electromagnetic wave shielding film includes: a step of forming an insulating layer in a semi-cured state by mixing and dispersing one or more resins selected from an epoxy resin and a polyurethane resin, a curing agent, a filler, and a solvent; and a step of forming a conductive shielding layer by mixing and dispersing an epoxy resin and copper as a conductive filler and including a curing agent and a solvent, which do not react with the copper, as a step of coating and heat-treating the conductive shielding layer on the insulating layer.

According to an exemplary embodiment, the insulating layer may be formed by including 7 to 18 wt% of a binder resin containing an epoxy resin, 4.5 to 8.5 wt% of a filler, 7 to 12 wt% of a curing agent, 65 to 70 wt% of a solvent, and other additives.

According to an exemplary embodiment, the conductive shielding layer may include 15 to 20 wt% of a binder resin which is the same as the binder resin of the insulating layer, 30 to 40 wt% of copper as a conductive filler, 1.5 to 2.5 wt% of a curing agent, and 35 to 45 wt% of a solvent.

According to an exemplary embodiment, a step of coating and heat-treating a composition of the insulating layer on a first protective film and a step of laminating a second protective film on a composition of the conductive shielding layer may be further included.

According to the present invention, oxidation of copper can be minimized by using a solvent, a binder, and additives which do not react with the copper in a copper ink composition, and, thus, the shielding efficiency equivalent to that of the existing product using silver-coated copper can be achieved and the manufacturing cost can be remarkably reduced.

That is, in the present invention, copper (Cu) is solely applied as a filler and unreactive solvent, binder resin and curing agent are applied in order to minimize ionization of the copper, and, thus, a resistance change ratio can be minimized without elution of copper ions.

Fig. 1 is a cross-sectional view showing a configuration of an electromagnetic wave shielding film according to an exemplary embodiment of the present invention.

Fig. 2 is a graph showing an electrical resistance according to an exemplary embodiment of the present invention.

Fig. 3 is a graph showing electromagnetic wave shielding efficiency according to Embodiment of the present invention and Comparative Examples.

Hereinafter, exemplary embodiments of an electromagnetic wave shielding film and a manufacturing method thereof according to the present invention will be described in detail.

Figure 1 shows a cross-sectional configuration of an electromagnetic wave shielding film according to an exemplary embodiment of the present invention.

Referring to this drawing, an electromagnetic wave shielding film according to the present invention includes an insulating film 10 and a conductive shielding layer 20 laminated on one surface thereof.

Although not illustrated, the electromagnetic wave shielding film according to the present invention may have a three-layered structure in which the conductive shielding layer 20, the insulating film 10, and a first protective film 30 are laminated in sequence.

Alternately, the electromagnetic wave shielding film may have a three-layered structure in which a second protective film 40, the conductive shielding layer 20, and the insulating film 10 are laminated in sequence.

Otherwise, the electromagnetic wave shielding film may have a four-layered structure in which the first protective film 30 is formed on the insulating film 10 and the second protective film 40 is formed under the conductive shielding layer 20.

Each protective film is a releasable film and can be separated and removed before and after the electromagnetic wave shielding film is attached to an electronic component.

Hereinafter, the insulating layer and the conductive shielding layer constituting the electromagnetic wave shielding film will be described.

1) Insulating layer

The insulating layer may include a binder resin, a curing agent, a filler, and a solvent. A method of forming the insulating layer will be described in detail with reference to a manufacturing method of the electromagnetic wave shielding film to be described below.

The binder resin is a reaction product obtained from a reaction between one or more resins selected from an epoxy resin (bisphenol A-type) and a polyurethane resin and an epoxy group-containing curing agent.

The epoxy resin has an excellent thermal resistance, which may cause improvement in lead-free solder reflow property.

In the case of using the epoxy resin, a curing agent reactive thereto is also used. The curing agent may be any one of isocyanate or polyamide or a combination thereof. Herein, the curing agent may be added in an amount of 7 to 12 wt% based on 100 wt% of the insulating layer. If the amount of the curing agent is less than the set range, an unreacted resin exists when the binder resin is cured, and, thus, a dried shielding film may be tacky. If the amount of the curing agent is more than the set range, the curing agent remains as unreacted reactant when the binder resin is cured, and, thus, the strength of the insulating layer may be decreased.

The polyurethane resin can improve flexibility of the electromagnetic wave shielding film, and when applied to a multi-layer FPCB, the polyurethane resin has a high elasticity and thus can alleviate tearing of the insulating layer.

Therefore, in the case of adding the epoxy resin together with the polyurethane resin as the binder resin, properties of the electromagnetic wave shielding film will be very superior.

Based on 100 wt% of the insulating layer, 2 to 5 wt% of the epoxy resin and 5 to 15 wt% of the polyurethane resin are included.

If the amount of the binder resin is less than the set range, flexibility of the shielding film may be decreased and cracks may occur on a surface of the manufactured shielding film. If the amount of the binder resin is more than the set range, a dry thickness after printing may be increased and the shielding film may be tacky.

The filler may be contained in an amount of 4.5 to 8.5 wt% based on 100 wt% of the insulating layer. The filler may be any one of carbon black and aluminum oxide (Al₂O₃) or a combination thereof. The carbon black and the aluminum oxide (Al₂O₃) may be input in an amount identical with or similar to each other. If the amount of the filler is less than the set range, an insulating resistance required for the insulating layer may have a resistance value lower than 10¹⁰to 10¹² and thus cannot satisfy the function as an insulator. If the amount of the filler is more than the set range, a thickness of the insulating layer may increase during microgravure printing, and, thus, the whole thickness of the shielding film may be increased more than necessary.

Ethyl acetate may be applied as the solvent and may be added in an amount of 65 to 70 wt% based on 100 wt% of the insulating layer. If the amount of the solvent is less than the set range, viscosity may be increased, and, thus, it is difficult to match a thickness to a set thickness during printing. If the amount of the solvent is more than the set range, the amounts of the filler, the resin, and the curing agent are decreased, and, thus, a thickness after drying may be decreased and it becomes difficult to achieve a set thickness of the manufactured shielding film.

2) Conductive shielding layer

The conductive shielding layer includes a binder resin, a curing agent, a conductive filler, and a solvent. A method of forming the conductive shielding layer will be described in detail with reference to the manufacturing method of the electromagnetic wave shielding film to be described below, similarly to the insulating layer.

The same resin as that of the insulating layer may be applied as the binder resin. For example, in terms of adhesion between the interfaces and film modification caused by heat, it is desirable to use the same binder resin for the insulating layer and the conductive shielding layer.

Therefore, in the present invention, an epoxy resin is applied as the binder resin of the conductive shielding layer and contained in an amount of 15 to 20 wt% based on 100 wt% of the conductive shielding layer. If the amount of the binder resin is less than the set range, the amount of the resin may be decreased as compared with the copper filler, and, thus, binding of the copper filler cannot be achieved and a product may be scratched by a hand or other devices during handling. If the amount of the binder resin is more than the set range, the amount of the resin may be increased as compared with the copper filler, and, thus, a surface resistance may be increased and shielding efficiency may be decreased accordingly.

The amount of the conductive filler is 30 to 40 wt% based on 100 wt% of the shielding layer. Preferably, when the amount of the conductive filler is within the set range, the conductive filler has excellent electrical conductivity and adhesion with respect to a substrate. That is, if the amount of the conductive filler is less than the set range, the manufactured shielding film may have an insufficient density, and, thus, a surface resistance may be increased and shielding efficiency may be decreased accordingly. If the amount of the conductive filler is more than the set range, the shielding film may have an increased density but viscosity may be increased, and, thus, a thickness may be increased during printing and product manufacturing cost may be increased.

As the conductive filler, copper may be applied solely, and one or more selected from dendrite, flake, and spherical metal particles may be used.

The solvent may employ those capable of preventing ionization of copper by minimizing a reaction with the copper filler and may be selected from at least one group of solvents having an ester group (-COOR), solvents having a hydroxyl group (-OH), solvents having an ester group (-COOR) and a hydroxyl group (-OH), solvents having a ketone group (C=O), and solvents having an alkyl group (-R) only or a combination of two or more thereof.

Preferably, the solvents having an ester group (-COOR) may include ethyl acetate, butyl carbitol acetate, dibasic ester, methyl dimethoxyacetate, methyl isobutyrate, dimethyl methylmalonate, methyl trans-4-oxo-2-pentenoate, and ethylene glycol diacetate; the solvents having a hydroxyl group (-OH) may include butyl carbitol, butyl cellosolve, and benzyl alcohol; the solvents having an ester group (-COOR) and a hydroxyl group (-OH) may include texanol(ester-alcohol); the solvents having a ketone group (C=O) may include methyl ethyl ketone (MEK); and the solvents having an alkyl group (-R) only may include toluene.

The solvent may be contained in amount of 40 to 50 wt% based on 100 wt% of the conductive shielding layer. If the amount of the solvent is less than the set range, viscosity may be increased, and, thus, it is difficult to match a thickness to a set thickness during printing. If the amount of the solvent is more than the set range, the amounts of the filler, the resin, and the curing agent are decreased, and, thus, a thickness after drying may be decreased and it becomes difficult to achieve a set thickness of the manufactured shielding film.

Like the filler, dicyandiamide which does not react with copper may be applied as the curing agent, and a curing accelerator formed of a urea resin may be further included.

The curing agent and the curing accelerator are individually added in an amount of 1.5 to 2.5 wt% based on 100 wt% of the conductive shielding layer. If the amount of the curing agent is less than the set range, an unreacted resin exists, and, thus, a dried shielding film may be tacky. If the amount of the curing agent is more than the set range, the curing agent remains as unreacted reactant when the resin is cured, and, thus, the strength may be decreased.

The first protective film and the second protective film prevent the electromagnetic wave shielding film from being contaminated with foreign substances from the external environment before being used by a user and protect a surface of the electromagnetic wave shielding film during a hot pressing process.

As the first protective film and the second protective film, a substrate film which is formed of polyethylene, polypropylene, or polyethylene terephthalate and of which a surface is treated with a silicon-based, fluorine-based, or long-chain alkyl acrylate-based release agent may be used in order to make it easier to separate the first protective film and the second protective film from the electromagnetic wave shielding film.

In the present invention, in terms of adhesion between the interfaces and film modification caused by heat, it is desirable to use the same binder resin for the insulating layer and the conductive shielding layer.

A manufacturing method of the electromagnetic wave shielding film according to the present invention is as follows.

Firstly, a first protective film having a release force of 200 gf/in is prepared.

Then, an insulating layer coating solution is prepared by mixing and dissolving an insulating layer composition including one or more selected from one or more resins selected from an epoxy resin and a polyurethane resin, an epoxy group-containing curing agent, and a filler, and the insulating layer coating solution is coated and heat-treated on the first protective film so as to form an insulating layer. The insulating layer coating solution may include one or more selected from a coloring and a curing catalyst.

The insulating layer coating solution is coated on the first protective film using a microgravure coater, and the heat treatment of the insulating layer coating solution is carried out at 100 to 180℃. During the heat treatment , the insulating layer composition is cured. Herein, preferably, the insulating layer may be formed in a semi-cured state.

Then, a conductive shielding layer composition including a binder resin formed of an epoxy resin, an epoxy group-containing curing agent, and a conductive filler is coated on the insulating layer using a slot die and then heat-treated thereon so as to form a conductive shielding layer.

The heat treatment of a coating solution for the conductive shielding layer is carried out at 100 to 180℃. During the heat treatment, the conductive shielding layer composition is cured.

Herein, the curing reaction in the insulating layer and the conductive shielding layer may include a semi-curing reaction of the reactants. If the semi-curing reaction is carried out during the heat treatment as such, an additional curing reaction is carried out in a subsequent process (for example, a laminating process, a pressing process such as hot pressing), and, thus, a fully cured reaction product may be obtained.

When the conductive shielding layer composition is prepared, a solvent may be added. Herein, ethyl acetate, toluene, methyl isobutyrate, dimethyl methylmalonate, dibasic ester, etc. may be used as the solvent.

Then, the second protective film is laminated on one surface of the conductive shielding layer, and, thus, a shielding film is completely manufactured.

Meanwhile, unlike the above descriptions, the insulating layer may be formed by coating the insulating layer composition on the first protective film, and the conductive shielding layer may be formed by coating the conductive shielding layer composition on the second protective film, and the respective methods are not particularly limited. Then, the insulating layer and the conductive shielding layer are laminated, and the laminating process may be completed by arranging the insulating layer and the conductive shielding layer to face each other and pressing them at 60 to 120℃.

If the electromagnetic wave shielding film manufactured as such is installed in an electronic component, for example, the second protective film is removed and the conductive shielding layer is temporarily bonded to be adjacent to the electronic component and then bonded through a pressing process such as hot pressing. Thereafter, the first protective film is removed.

The electromagnetic wave shielding film of the present invention manufactured by the above-described manufacturing method can be reliably applied to one or both surfaces of an FPCB required to have a high adhesion with an electronic component and a high flexibility and can also effectively diminish various electromagnetic waves generated in a printed circuit board.

Particularly, since copper is used solely as the conductive filler, the shielding film has shielding efficiency almost equivalent to that of the existing shielding film using silver-coated copper as a conductive filler and can be remarkably reduced in manufacturing cost.

The present invention will be described in more detail with reference to Embodiments as shown in Table 1 and Table 2. However, the following Embodiments are just provided to more clearly explain the present invention but do not limit the scope of protection of the present invention.

Embodiment

An insulating layer coating solution was prepared by mixing and dissolving 3.5 wt% of bisphenol A-type epoxy resin (Kukdo YD-128), 10 wt% of a polyurethane resin, 5 wt% of isocyanate, 5 wt% of polyamide, 3 wt% of carbon black, 5 wt% of aluminum oxide, and 68.5 wt% of ethyl acetate.

An insulating layer in a semi-cured state was formed to a thickness of 5 mm by coating the insulating layer coating solution on one surface of a first protective film (release force of 200 gf/in) using a microgravure coater and drying the insulating layer coating solution at a temperature of 150℃ for 5 minutes.

Then, a curable conductive adhesive composition was obtained by dispersing and mixing 17.7 wt% of bisphenol A-type epoxy resin (Kukdo YD-128), 35 wt% of copper, 1.8 wt% of dicyandiamide, 1.8 wt% of a urea resin, 11.7 wt% of ethyl acetate, 27 wt% of toluene, and 5 wt% of dibasic ester.

A conductive shielding layer was formed to a thickness of 13 mm by coating the curable conductive adhesive composition on the insulating layer using a slot die coater and drying the curable conductive adhesive composition at a temperature of 150℃ for 5 minutes.

Then, a second protective film (release force of 250 gf/in) was laminated on the electromagnetic wave shielding layer. Thus, an electromagnetic wave shielding film was manufactured.

Comparative Example 1

An electromagnetic wave shielding film was manufactured with the same compositions and the same process conditions as Embodiment except that an imidazole resin reactive to copper was used as a curing accelerator.

Comparative Example 2

An electromagnetic wave shielding film was manufactured with the same compositions and the same process conditions as Embodiment except that silver-coated copper powder was used as a filler in a composition for a shielding layer.

Table 1

	Composition
Resin	Epoxy (bisphenol A-type) 3.5%Polyurethane: 10%
Curing agent	Isocyanate: 5%Polyamide 5%
Filler	Carbon black: 3%Al₂O₃: 5%
Solvent and other additives	Ethyl acetate 68.5%

Table 2

	Embodiment	Comparative Example 1	Comparative Example 2
	Cu only	Cu only	Ag/Cu (10% Ag-coated powder)
Filler	Cu 35%	Cu35%	Ag/Cu35%
Resin	Bisphenol A-type (Kukdo YD-128)17.7%	Bisphenol A-type (Kukdo YD-128)17.7%	Bisphenol A-type (Kukdo YD-128)17.7%
Curing agent	Dicyandiamide1.8%	Dicyandiamide1.8%	Dicyandiamide1.8%
Curing accelerator	Urea1.8%	Imidazol1.8%	Urea1.8%
Solvent	Ethyl acetate 11.7Toluene 17Methyl isobutyrate 5Dimethyl methylmalonate 5Dibasic Ester 5	Ethyl acetate 11.7Toluene 17Methyl isobutyrate 5Dimethyl methylmalonate 5*Dibasic Ester 5	Ethyl acetate 11.7Toluene 17Methyl isobutyrate 5Dimethyl methylmalonate 5Dibasic Ester 5
Remarks	Cu added	Cu addedCuring accelerator: Imidazol	Metal powder Ag/Cu added

The semi-cured electromagnetic wave shielding film stored at room temperature and at a humidity of 50% after being manufactured was overlapped with and temporarily bonded to a 250 mm long PI (polyimide, Kapton) film and then cured at a temperature of 160℃ under a pressure of 30 kgf for 60 minutes by way of hot pressing so as to prepare a specimen for measuring electrical conductivity. Then, a surface resistance value and shielding efficiency were measured.

(1) Surface resistance

As a result of measuring a change in resistance value of the specimen for 3 weeks, it can be seen from Table 3 and Figure 2 that a change in resistance value is insignificant based on 201.3.

Further, referring to Table 3, the shielding film of Embodiment has a surface resistance value almost equivalent to 189.6 of Comparative Example 2 and considerably lower than 506.7 of Comparative Example 1.

(2) Shielding efficiency

A reference sample and a load sample were cut in an appropriate size and requested to be measured by an electromagnetic wave shielding measurement institution (Korea Testing Laboratory). The shielding efficiency average in the range of 30 MHz to 1.5 GHz was measured.

*Referring to Table 3, the shielding efficiency average of Embodiment was 49.3 dB almost equivalent to 52.0 dB of Comparative Example 2 and considerably higher than 30.0 dB of Comparative Example 1.

That is, the electromagnetic wave shielding film according to Embodiment employs Cu only as the conductive filler and uses the binder resin, the solvent and the curing agent which do not react with Cu, and, thus, ink does not discolor and the electromagnetic wave shielding film has the shielding efficiency almost equivalent to Comparative Example 2 using expensive silver-coated copper as the filler. Therefore, reduction in manufacturing cost can be induced.

*

Table 3

	Embodiment	Comparative Example 1	Comparative Example 2
	Cu only	Cu only	Ag/Cu (10% Ag-coated powder)
Surface resistance (mΩ/□)	201.3	506.7	189.6
Shielding efficiency (dB)	49.3	30.0	52.0
Ink discoloration	x	O	x

Although the present invention has been described with reference to the accompanying drawings, this is just one of various exemplary embodiments including the subject matter of the present invention and intends to allow those skilled in the art to easily implement the present invention. It is clear that the present invention is not limited to the above-described exemplary embodiments. Therefore, the scope of the present invention should be construed by the following claims. Without departing from the subject matter of the present invention, all the technical spirits within the scope equivalent to the subject matter of the present invention is included in the right scope of the present invention by modifications, substitutions, changes, and the like. Also, it is clear that some of the drawing configuration are intended for more clearly describing the configuration and are more exaggerated or shortened than the actual ones.

[Reference Signs List]

1: Electromagnetic wave shielding film

10: Insulating layer

20: Shielding layer

30: First protective layer

40: Second protective layer

Claims

An electromagnetic wave shielding film comprising:

an insulating layer including a binder resin containing an epoxy resin, a filler, a curing agent, a solvent, and other additives; and

a conductive shielding layer including a binder resin which is the same as the binder resin of the insulating layer, copper as a conductive filler, a curing agent, and a solvent,

wherein the solvent is selected from at least one group of solvents having an ester group (-COOR), solvents having a hydroxyl group (-OH), solvents having an ester group (-COOR) and a hydroxyl group (-OH), solvents having a ketone group (C=O), and solvents having an alkyl group (-R) only or a combination of two or more thereof.
The electromagnetic wave shielding film of claim 1,

wherein the insulating layer includes 7 to 18 wt% of the binder resin, 4.5 to 8.5 wt% of the filler, 7 to 12 wt% of the curing agent, and 65 to 70 wt% of the solvent based on 100 wt% of the insulating layer.
The electromagnetic wave shielding film of claim 1,

wherein the binder resin of the insulating layer further includes a polyurethane resin.
The electromagnetic wave shielding film of claim 3,

wherein the polyurethane resin is added in an amount of 5 to 15 wt% with respect to 100 wt% of the insulating layer.
The electromagnetic wave shielding film of claim 1,

wherein the conductive shielding layer includes 15 to 20 wt% of the binder resin, 30 to 40 wt% of the conductive filler, 1.5 to 2.5 wt% of the curing agent, and 35 to 45 wt% of the solvent based on 100 wt% of the conductive shielding layer.
The electromagnetic wave shielding film of claim 1,

wherein the curing agent of the conductive shielding layer further includes a urea resin as a curing accelerator.
The electromagnetic wave shielding film of claim 6,

wherein the curing accelerator is added in an amount of 1.5 to 2.5 wt% with respect to 100 wt% of the conductive shielding layer.
The electromagnetic wave shielding film of claim 1, further comprising:

a releasable protective film laminated on a lower surface of the conductive layer, an upper surface of the insulating layer, or the lower surface of the conductive layer and the upper surface of the insulating layer may be further included.
A manufacturing method of an electromagnetic wave shielding film comprising:

a step of forming an insulating layer in a semi-cured state by mixing and dispersing one or more resins selected from an epoxy resin and a polyurethane resin, a curing agent, a filler, and a solvent; and

a step of forming a conductive shielding layer by mixing and dispersing an epoxy resin and copper as a conductive filler and including a curing agent and a solvent, which do not react with the copper, as a step of coating and heat-treating the conductive shielding layer on the insulating layer.
The manufacturing method of an electromagnetic wave shielding film of claim 9,

wherein the insulating layer is formed by including 7 to 18 wt% of a binder resin containing an epoxy resin, 4.5 to 8.5 wt% of a filler, 7 to 12 wt% of a curing agent, 65 to 70 wt% of a solvent, and other additives.
The manufacturing method of an electromagnetic wave shielding film of claim 9,

wherein the conductive shielding layer includes 15 to 20 wt% of a binder resin which is the same as a binder resin of the insulating layer, 30 to 40 wt% of copper as a conductive filler, 1.5 to 2.5 wt% of a curing agent, and 35 to 45 wt% of a solvent.
The manufacturing method of an electromagnetic wave shielding film of claim 9, further comprising:

a step of coating and heat-treating a composition of the insulating layer on a first protective film; and

a step of laminating a second protective film on a composition of the conductive shielding layer.