KR101690166B1 - Electromagnetic wave shielding film and manufacturing method thereof - Google Patents

Abstract

An electromagnetic wave shielding film is disclosed. The disclosed electromagnetic shielding film comprises an insulating film containing 7 to 18% by weight of a binder resin containing an epoxy resin, 4.5 to 8.5% by weight of a filler, 7 to 12% by weight of a curing agent, 65 to 70% by weight of a solvent and other additives layer; A binder resin containing 15 to 20% by weight of the same material as the binder resin of the insulating layer, 30 to 40% by weight of copper as an electrically conductive filler, 1.5 to 2.5% by weight of a curing agent, and 35 to 45% Wherein the solvent comprises a solvent having an ester group (-COOR), a solvent having a hydroxyl group (-OH), a solvent having both an ester group (-COOR) and a hydroxyl group (-OH) A solvent having a ketone group (C = O), a solvent having only an alkyl group (-R), or a combination of two or more thereof.

Description

TECHNICAL FIELD The present invention relates to an electromagnetic wave shielding film and a manufacturing method thereof,

The present invention relates to an electromagnetic wave shielding film and a method of manufacturing the same, and more particularly, to an electromagnetic wave shielding film having a shielding efficiency equivalent to that of a conventional product and capable of reducing manufacturing costs, and a manufacturing method thereof.

2. Description of the Related Art Recently, electronic devices used in portable mobile devices, notebook computers, personal digital assistants (PDAs), electronic organizers, liquid crystal displays (LCDs), organic light emitting devices (OLEDs) and plasma display devices Together, they are being studied to speed up the signal transmission between electronic components.

[0003] As the printed circuit board (PCB) becomes finer, damage to electromagnetic interference (EMI) due to generation of electromagnetic noise between adjacent circuits is increasing.

In order to effectively block such electromagnetic waves, a printed circuit board (PCB) must be wrapped with a metal film having excellent electrical conductivity so that electromagnetic waves generated between the circuits can be attenuated through the metal film.

To this end, a product of a conductive adhesive film has been applied which attaches a metal thin film having excellent conductivity on a printed circuit board, applies a conductive paste, or forms a film by heating.

Particularly, in the case of a flexible printed circuit board (FPCB) such as a rigid flexible board, there is a great demand for a product of an adhesive film type having excellent step-by-step durability and electrification resistance.

Further, there is a growing need to develop an electromagnetic wave shielding film having electrical conductivity excellent in level filling property in Rigid-Flex type FPCB while satisfying adhesion with a substrate.

For example, as a conventional electromagnetic shielding adhesive film, a shielding layer having a conductive adhesive layer and, if necessary, a metal thin film layer on one side of a cover film, and a reinforcing shielding film in which an adhesive layer and a releasable reinforcing film are sequentially laminated on the other surface (See Patent Document 1).

Further, a shielding film having a shielding layer having a conductive adhesive layer and / or a metal thin film and a base film made of an aromatic polyamide resin is known (see Patent Document 2).

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

However, recently developed electromagnetic wave shielding films use silver coated silver having high thermal conductivity in order to increase the shielding efficiency. However, since costly silver is used, manufacturing cost of the shielding film is increased.

Patent Document 1: Japanese Patent Application Laid-Open No. 2003-298285 Patent Document 2: Japanese Patent Application Laid-Open No. 2004-273577 Patent Document 3: Japanese Patent Application Laid-Open No. 2004-95566

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

The present invention also provides an electromagnetic wave shielding film and a method of manufacturing the electromagnetic wave shielding film, which have a shielding efficiency equal to that of existing products and can reduce manufacturing costs.

The electromagnetic wave shielding film according to one embodiment is a film comprising 7 to 18% by weight of a binder resin containing an epoxy resin, 4.5 to 8.5% by weight of a filler, 7 to 12% by weight of a curing agent, 65 to 70% An insulating layer containing a metal oxide; A binder resin containing 15 to 20% by weight of the same material as the binder resin of the insulating layer, 30 to 40% by weight of copper as an electrically conductive filler, 1.5 to 2.5% by weight of a curing agent, and 35 to 45% Wherein the solvent comprises a solvent having an ester group (-COOR), a solvent having a hydroxyl group (-OH), a solvent having both an ester group (-COOR) and a hydroxyl group (-OH) A solvent having a ketone group (C = O), a solvent having only an alkyl group (-R), or a combination of two or more thereof.

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

According to one embodiment, the polyurethane resin may be added in an amount of 5 to 15% by weight based on 100% by weight of the insulating layer.

According to one embodiment, the curing agent of the conductive shielding layer may further include a urea resin which is a curing accelerator.

According to one embodiment, the curing accelerator may be added in an amount of 1.5 to 2.5% by weight based on 100% by weight of the conductive shielding layer.

According to an embodiment of the present invention, it is possible to further include a release protection film laminated on the lower surface of the conductive layer, the upper surface of the insulating layer, or the lower surface of the conductive layer and the upper surface of the insulating layer.

The method of manufacturing an electromagnetic wave shielding film according to one embodiment includes the steps of mixing and dispersing at least one resin selected from an epoxy resin and a polyurethane resin, a curing agent, a filler, and a solvent to form a semi-cured insulating layer; Coating and heat-treating the conductive shielding layer on the insulating layer, comprising: mixing and dispersing copper as an epoxy resin and a conductive filler; and forming a conductive shielding layer including a curing agent and a solvent that are not reactive with the copper do.

According to one embodiment, the insulating layer may include a binder resin containing 7 to 18 wt% of an epoxy resin, 4.5 to 8.5 wt% of filler, 7 to 12 wt% of a curing agent, 65 to 70 wt% of a solvent, As shown in FIG.

According to one embodiment, the conductive shield layer may include 15 to 20 wt% of a binder resin containing the same material as the binder resin of the insulating layer, 30 to 40 wt% of copper as an electrically conductive filler, 1.5 to 2.5 wt% , And 35 to 45% by weight of a solvent.

According to one embodiment, the method may further include coating and heat-treating the insulating layer composition on the first protective film, and laminating the second protective film on the conductive shielding layer composition.

According to the present invention, since the oxidation of copper is minimized by using a solvent, a binder and an additive which are not reactive with copper in the copper ink composition, the manufacturing cost is remarkably high while having a shielding efficiency equal to that of the conventional silver- .

That is, in the present invention, by applying copper (Cu) solely as a filler and minimizing the ionization of the resulting copper, by applying a solvent having no reactivity, a binder resin and a curing agent, And the resistance change rate can be minimized.

1 is a cross-sectional view showing the structure of an electromagnetic wave shielding film according to an embodiment of the present invention.
2 is a graph showing electrical resistance according to an embodiment of the present invention.
3 is a graph showing the electromagnetic shielding ratio according to one embodiment of the present invention and a comparative example.

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

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

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

Although not shown, the electromagnetic wave shielding film of the present invention may have a three-layer structure in which the conductive shielding layer 20, the insulating layer 10, and the first protective film 30 are sequentially laminated.

Or a three-layer structure in which the second protective film 40, the conductive shielding layer 20, and the insulating layer 10 are sequentially stacked.

Or a four-layer structure in which the first protective film 30 is formed on the insulating layer 10 and the second protective film 40 is formed on the lower portion of the conductive shield layer 20.

Each protective film may be separated and removed as a release film before and after the process of attaching the electromagnetic wave shielding film to the 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. The method for forming the insulating layer will be described in detail in a method for manufacturing an electromagnetic wave shielding film to be described later.

The binder resin is a reaction product obtained by the reaction of at least one selected from an epoxy resin (bisphenol A type) and a polyurethane resin with an epoxy group-containing curing agent.

Epoxy resin can improve the lead-free solder reflow property due to excellent heat resistance.

When an epoxy resin is used, a reactive curing agent is preferably used together. The curing agent may be any one or a combination of isocyanate or polyamide. At this time, the curing agent may be added in an amount of 7 to 12 wt% based on 100 wt% of the insulating layer. If the content of the curing agent is less than the setting range, tacky may occur in the dried shielding film due to the presence of the unreacted resin during curing of the binder resin. If the content of the curing agent exceeds the setting range, So that the strength of the insulating layer can be lowered.

The polyurethane resin can improve the flexibility of the electromagnetic wave shielding film, and when applied to a multi-layer FPCB, the tearing of the insulating layer can be alleviated due to the high elasticity property.

Therefore, when the epoxy resin and the polyurethane resin are added together as the binder resin, the physical properties of the electromagnetic wave shielding film can be remarkably improved.

The content of the epoxy resin is 2 to 5% by weight based on 100% by weight of the insulating layer, and 5 to 15% by weight of the polyurethane resin is applied.

If the content of the binder resin is less than the set range, the flexibility of the shielding film is reduced and cracking may occur on the surface of the produced shielding film. If the content of the binder resin exceeds the setting range, tacky may occur.

The filler may be contained in an amount of 4.5 to 8.5 wt% based on 100 wt% of the insulating layer, and the filler may be a combination of one or both of carbon black and aluminum oxide (Al ₂ O ₃ ). Carbon black and aluminum oxide (Al ₂ O ₃ ) may be added in the same or nearly similar amounts. If the content of the filler is less than the above-mentioned range, the insulating resistance of the insulating layer should be 10 ¹⁰ to 10 ¹² Ω If the content of the filler exceeds the setting range, the thickness of the entire shielding film may become thicker than necessary due to an increase in the insulating layer thickness when printed with microgravure.

The solvent may be ethyl acetate and may be added in an amount of 65 to 70% by weight based on 100% by weight of the insulating layer. If the content of the solvent is less than the setting range, the viscosity becomes high and it is difficult to set the thickness at the time of printing. If the content of the solvent exceeds the setting range, the content occupied by the filler, resin and hardener decreases, It becomes difficult to realize the set thickness of the shielding film to be completed.

2) Conductive shielding layer

The conductive shielding layer includes a binder resin, a hardener, a conductive filler, and a solvent. The method of forming the conductive shielding layer will be described in detail in the method of manufacturing an electromagnetic wave shielding film to be described later as in the case of the insulating layer.

The same resin as the insulating layer can be applied to the binder resin. For example, the insulating layer and the conductive shielding layer are preferably made of the same binder resin in terms of the interfacial adhesion force and the film deformation due to heat.

Therefore, in the present invention, epoxy resin is applied to the binder resin of the conductive shielding layer, and 15 to 20 wt% of the epoxy resin is applied based on 100 wt% of the conductive shielding layer. If the content of the binder resin is less than the set range, the content of the resin relative to the copper filler is reduced, so that the copper filler can not be bound and scratches may be caused by hand or other equipment during handling of the product. If the setting range is exceeded, the resin content is increased compared to the copper filler, so that the sheet resistance is increased and the shielding ratio is decreased as a result.

The content of the conductive filler is 30 to 40% by weight based on 100% by weight of the shielding layer. When the content of the conductive filler satisfies the setting range, it is preferable since the electrical conductivity and adhesion to the substrate are excellent. That is, when the content of the conductive filler is less than the set range, the density of the shielding film becomes insufficient and the sheet resistance increases and the shielding rate decreases. When the content of the conductive filler exceeds the set range, the tightness of the shielding film increases As the viscosity increases, the thickness increases during printing, which increases the manufacturing cost of the product.

The conductive filler may be at least one selected from the group consisting of dendrite, flake, and spherical shaped metal particles.

Solvents that can prevent ionization of copper by minimizing the reaction with copper filler are applied. Solvents having an ester group (-COOR), a solvent having a hydroxyl group (-OH), an ester group (-COOR) A solvent having a hydroxyl group (-OH) at the same time, a solvent having a ketone group (C = O) and a solvent having only an alkyl group (-R), or a combination of two or more thereof.

Preferably, the solvent having an ester group (-COOR) includes ethyl acetate, butyl carbitol acetate, dibasic ester, methyl dimethoxyacetate, methyl isobutyrate, dimethyl methylmalonate, methyl trans-4-oxo-2-pentenoate and ethylene glycol diacetate (-COOR) and hydroxyl group (-OH) simultaneously contain Texanol (ester-alcohol). The solvent containing hydroxyl group (-OH) includes Butyl carbitol, Butyl cellosolve and Benzyl alcohol. , The solvent having a ketone group (C = O) includes methyl ethyl ketone (MEK), and the solvent having only an alkyl group (-R) includes Toluene.

The solvent may be applied in an amount of 40 to 50 wt% based on 100 wt% of the conductive shielding layer. If the content of the solvent is less than the setting range, the viscosity becomes high and it is difficult to set the thickness at the time of printing. If the content of the solvent exceeds the setting range, the content occupied by the filler, resin and hardener decreases, It becomes difficult to realize the set thickness of the shielding film to be completed.

As the filler, the hardener is applied with dicyandiamide which is not reactive with copper, and may further include a hardening accelerator made of a urea resin.

The curing agent and the curing accelerator are added in an amount of 1.5 to 2.5% by weight based on 100% by weight of the conductive shielding layer, respectively. If the content of the curing agent is less than the set range, tacky remains in the dried shielding film due to the presence of the unreacted resin. If the content of the curing agent exceeds the set range, the cured resin is present as an unreacted material, have.

The first protective film and the second protective film prevent contamination of the electromagnetic wave shielding film by the foreign environment from the external environment until the electromagnetic shielding film is used by the user and protect the surface in the high temperature press process.

The first protective film and the second protective film may be formed on the surface of a substrate film formed of a material such as polyethylene, polypropylene, or polyethylene terephthalate to have a silicone-based, fluorine-based, long-chain alkyl acrylate-based And the like.

In the present invention, it is preferable that the insulating layer and the conductive shielding layer use the same binder resin in view of the interfacial adhesion force and the film deformation due to heat.

A method of manufacturing an electromagnetic wave shielding film according to the present invention will be described below.

First, a first protective film having a releasing force of 200 gf / in is prepared.

Next, an insulating layer coating liquid is prepared by mixing and dissolving an insulating layer composition containing at least one selected from an epoxy resin and a polyurethane resin, at least one selected from an epoxy group-containing curing agent and a filler, Is applied on a film and then heat-treated to form an insulating layer. The insulating layer coating solution may contain at least one selected from a coloring agent and a curing catalyst.

The insulating layer coating liquid is applied on the first protective film by using a microgravure coater, and the heat treatment of the insulating layer coating liquid is performed at 100 to 180 ° C, during which the curing reaction of the insulating layer composition occurs. At this time, it is preferable to form the insulating layer in a semi-cured state.

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

The heat treatment of the coating liquid of the conductive shielding layer is performed at 100 to 180 ° C, and the curing reaction of the conductive shielding layer composition occurs during the heat treatment process.

At this time, the curing reaction in the insulating layer and the conductive shielding layer may include a semi-curing reaction of the reactant. When the semi-curing reaction progresses during the heat treatment as described above, the additional curing reaction proceeds further in a subsequent process (for example, a pressing process such as lint, hot press, etc.) to obtain a completely cured reaction product.

A solvent may be further added in the production of the conductive shielding layer composition. Ethyl acetate, toluene, methyl isobutyrate, dimethyl methylmalonate, and dibasic ester may be used as the solvent.

Finally, the shielding film is completed by laminating the second protective film on one surface of the conductive shielding layer.

Alternatively, 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, The method is not particularly limited. Thereafter, the insulating layer and the conductive shielding layer are joined together, and the laminating process can be completed by, for example, carrying out a process of pressing the insulating layer and the conductive shielding layer together at 60 to 120 ° C.

When the electromagnetic shielding film thus manufactured is mounted on an electronic component, for example, the second shielding film is removed and the conductive shielding layer is brought into contact with the electronic component adjacent to the electronic shielding film. Then, the electromagnetic shielding film is subjected to a pressing process such as a hot press, 1 Following the process of removing the protective film.

The electromagnetic wave shielding film of the present invention formed according to the above-described manufacturing method can be reliably applied to a cross section or both sides of an FPCB which requires high adhesion strength with an electronic part, flexibility, etc., and can effectively attenuate various electromagnetic waves generated from a printed circuit board .

Particularly, by using copper alone as a conductive filler, it is possible to obtain a shielding efficiency almost equal to that of a conventional shielding film using silver-coated copper as a conductive filler, and the manufacturing cost can be remarkably reduced.

The present invention will be described in more detail with reference to Examples of Tables 1 and 2. It should be noted, however, that the following examples are for the purpose of more clearly illustrating the present invention and are not intended to limit the scope of protection of the present invention.

Example

, 3.5 wt% of bisphenol A type epoxy resin (National Highway YD-128), 10 wt% of polyurethane resin, 5 wt% of isocyanate, 5 wt% of polyamide, 3 wt% of carbon black, Were mixed and dissolved to prepare an insulating layer coating solution.

The insulating layer coating solution was coated on one side of a first protective film (release force of 200 gf / in) using a micro gravure coater and dried at a temperature of 150 캜 for 5 minutes to form a semi-cured insulating layer having a thickness of 5 탆.

Next, 17.7 wt% of bistenol A type epoxy resin (National Road YD-128), 35 wt% of copper, 1.8 wt% of dicyandiamide, 1.8 wt% of urea resin, 11.7 wt% of ethyl acetate, 27 wt% And 5 wt% of dibasic ester were dispersed and mixed to obtain a curable conductive adhesive composition.

A curable conductive adhesive composition was coated on the insulating layer using a slot die coater and dried at a temperature of 150 캜 for 5 minutes to form a conductive shielding layer having a thickness of 13 탆.

Thereafter, a second protective film (releasing force: 250 gf / in) was laminated on the electromagnetic wave shielding layer to prepare an electromagnetic wave shielding film.

Comparative Example  One

An electromagnetic wave shielding film was produced under the same composition and process conditions as those of the examples except that an imidazole resin having reactivity with copper was used as a curing accelerator.

Comparative Example  2

An electromagnetic wave shielding film was produced under the same composition and process conditions as those of the examples except that the silver coating copper powder was used as a filler in the composition of the shielding layer.

Composition Resin Epoxy (bisphenol A-type) 3.5%
Polyurethane: 10% Curing agent Isocyanate: 5%
Polyamide 5% Filler Carbon black: 3%
Al ₂ O ₃ : 5% Solvent and other additives Ethyl acetate 68.5%

Embodiment Comparative Example 1 Comparative Example 2 Cu only Cu only Ag / Cu (10% Ag-coated powder) Filler Cu
35% Cu
35% Ag / Cu
35% 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 Dicyandiamide
1.8% Dicyandiamide
1.8% Dicyandiamide
1.8% Curing accelerator Urea
1.8% Imidazole
1.8% Urea
1.8% Solvent Ethyl acetate 11.7
Toluene 17
Methyl isobutyrate 5
Dimethyl methylmalonate 5
Dibasic Ester 5 Ethyl acetate 11.7
Toluene 17
Methyl isobutyrate 5
Dimethyl methylmalonate 5

* Dibasic Ester 5 Ethyl acetate 11.7
Toluene 17
Methyl isobutyrate 5
Dimethyl methylmalonate 5
Dibasic Ester 5 Remarks Cu added Cu added
Curing accelerator: Imidazole Metal powder Ag / Cu added

After completion of the manufacture, the semi-cured electromagnetic shielding film stored at room temperature and 50% humidity was overlaid on a PI (Polyimide, Kapton) film having a width of 250 mm and placed thereon and heated at 160 ° C under a pressure of 30 kgf The samples were cured for 60 minutes to prepare electrical conductivity measurement specimens, and the sheet resistance and shielding ratio were measured.

(1) sheet resistance

As a result of measuring the change of the resistance value of the test piece for 3 weeks, it can be seen that the resistance value is not changed with reference to 201.3 as shown in Table 3 and FIG.

Also, referring to Table 3, it can be seen that the shielding film of the example has a sheet resistance value almost equal to 189.6 of Comparative Example 2, and has a significantly lower value than the sheet resistance value 506.7 of Comparative Example 1. [

(2) Shielding rate

The reference and load specimens were cut to the appropriate dimensions and commissioned to the agency measuring the electromagnetic shielding (Korea Industrial Technology Development Institute). The average of the shielding rate of the 30 MHz to 1.5 GHz band was measured.

Referring to Table 3, it can be seen that the shielding ratio of the embodiment is 49.3dB on average, which is approximately equal to 52.0dB of Comparative Example 2 and has a significantly higher shielding rate than that of Comparative Example 1 of 30.0dB.

That is, the electromagnetic wave shielding film according to the embodiment uses Cu as a conductive filler alone and uses a binder resin, a solvent, and a curing agent which are not reactive with Cu, so that there is no discoloration of the ink, Since the shielding ratio is almost equal to that of Comparative Example 2, the manufacturing cost can be reduced.

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

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it should be understood that various changes and modifications will be apparent to those skilled in the art. It is to be understood that the present invention is not limited to the above-described embodiments. Accordingly, the scope of protection of the present invention should be construed according to the following claims, and all technical ideas which fall within the scope of equivalence by alteration, substitution, substitution, Range. In addition, some of the drawings are for explaining the configuration of the present invention more clearly and may be provided in an exaggerated or reduced size than actual.

One; EMI shielding film
10; Insulating layer
20; Shielding layer
30; The first protective film
40; The second protective film

Claims (12)

An insulating layer comprising a binder resin including an epoxy resin, a filler, a curing agent, a solvent and other additives;
A conductive shielding layer comprising a binder resin containing the same material as the binder resin of the insulating layer but not reactive with copper, a curing agent which is not reactive with copper as a conductive filler, and a solvent which is not reactive with copper,
The solvent of the insulating layer and the conductive shielding layer may be a solvent having an ester group (-COOR), a solvent having a hydroxyl group (-OH), a solvent having both an ester group (-COOR) and a hydroxyl group (-OH) (-R), or two or more groups are combined,
The binder resin of the insulating layer contains 7 to 18 wt%, the filler of 4.5 to 8.5 wt%, the curing agent of 7 to 12 wt%, and the solvent of 65 to 70 wt% based on 100 wt% of the insulating layer,
The binder resin, the conductive filler, and the conductive filler of the conductive shielding layer may be used in an amount of 15 to 20 wt%, 30 to 40 wt%, 1.5 to 2.5 wt%, and 35 to 45 wt%, respectively, based on 100 wt% And wherein the control unit comprises:
Wherein the binder resin of the insulating layer further comprises a polyurethane resin,
Wherein the polyurethane resin is added in an amount of 5 to 15% by weight based on 100% by weight of the insulating layer,
Wherein the curing agent of the conductive shielding layer further comprises a urea resin which is a curing accelerator,
Wherein the curing accelerator is added in an amount of 1.5 to 2.5% by weight based on 100% by weight of the conductive shielding layer.
delete delete delete delete delete delete The method according to claim 1,
Further comprising a release protective film laminated on the lower surface of the conductive shielding layer, the upper surface of the insulating layer, or the lower surface of the conductive shielding layer and the upper surface of the insulating layer.
Mixing and dispersing at least one resin selected from an epoxy resin and a polyurethane resin, a curing agent, a filler and a solvent to form a semi-cured insulating layer;
Coating and heat-treating a conductive shielding layer on the insulating layer, the method comprising: mixing and dispersing copper as an electrically conductive filler and an epoxy resin which is not reactive with copper, and a solvent which is not reactive with copper, Forming a conductive shielding layer;
Lt; / RTI >
The solvent of the insulating layer and the conductive shielding layer may be a solvent having an ester group (-COOR), a solvent having a hydroxyl group (-OH), a solvent having both an ester group (-COOR) and a hydroxyl group (-OH) (-R), or two or more groups are combined,
The insulating layer is formed to contain 7 to 18 wt% of a binder resin including 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,
Wherein the conductive shielding layer comprises 15 to 20 wt% of a binder resin containing the same material 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, 35 to 45 wt% Of a solvent,
Wherein the polyurethane resin is added in an amount of 5 to 15% by weight based on 100% by weight of the insulating layer,
Wherein the curing agent of the conductive shielding layer further comprises a urea resin which is a curing accelerator,
Wherein the curing accelerator is added in an amount of 1.5 to 2.5% by weight based on 100% by weight of the conductive shielding layer.
delete delete 10. The method of claim 9,
Coating and heat-treating the insulating layer on the first protective film, and bonding the second protective film to the conductive shielding layer.

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