KR20190019874A - Electro-magnetic interference shield flim - Google Patents

Abstract

The present invention relates to an electro-magnetic interference (EMI) shield film, and more particularly, to an EMI shield film which adheres to a stepped or curved surface with excellent adhesion and has remarkable shielding performance. The EMI shield film includes: an electro-magnetic wave shielding layer including a conductive nanofiber web in which a plurality of nanofibers including conductive nanofibers form a three-dimensional network to form a plurality of pores, and a conductive adhesive layer; and a protective layer provided on the electro-magnetic wave shielding layer.

Description

EMI shielding film < RTI ID = 0.0 >

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an EMI shielding film, and more particularly, to an EMI shielding film which is adhered to an adherend surface having a step or a curvature with excellent adhesion and is excellent in shielding performance.

Electron blue means the electric / magnetic wavelength including the electric and magnetic fields and the squeak wave generated by electrical products and electronic products used in various places around us. Particularly, electromagnetic waves generated from high frequency electronic devices cause malfunction due to electromagnetic interference with neighboring electronic devices and can adversely affect the human brain.

The electromagnetic wave shielding film is a film for shielding electromagnetic waves emitted from various electronic devices and is a component that is used in various fields. In particular, inter-wavelength interference may occur between the components in various electronic products due to the emission of electromagnetic waves, resulting in the malfunction and failure of the electronic product, and there is also a controversy about the harmfulness to the human body to the user of the electronic device.

As a conventional electromagnetic wave shielding film, there is known an electromagnetic wave shielding film in which a cover film has a shield layer composed of a conductive adhesive layer and a metal thin film layer on one side, and an adhesive layer and a releasability enhancing film are sequentially laminated on the other side. However, in the case of such an electromagnetic wave shielding film, since the flexibility of the electromagnetic shielding film is very low, there is a problem that when the electromagnetic wave shielding film is applied to an adhered surface having a step difference, the shielding film does not adhere properly between the electromagnetic shielding film and the adherend surface. In addition, when a physical external force is applied to the step or bending portion in order to prevent this, a crack of the metal thin film layer may occur in the excited portion, and thus it may be difficult to exhibit the desired level of electromagnetic wave shielding performance.

Accordingly, there is an urgent need to develop an EMI shielding film which is highly flexible and adheres to an adherend surface having a curvature or step difference with excellent adhesion, thereby preventing the deterioration of electromagnetic wave shielding performance.

Korean Patent Registration No. 10-0250067

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-described problems, and it is an object of the present invention to provide an electromagnetic wave shielding apparatus, It is an object of the present invention to provide a shielding film.

It is another object of the present invention to provide an EMI shielding film having applications that can be applied on various types of chips having a step or a substrate on which such a chip is mounted.

According to an aspect of the present invention, there is provided an electromagnetic wave shielding layer including a conductive nanofiber web and a conductive adhesive layer, wherein the plurality of nanofibers including the conductive nanofibers form a three-dimensional network to form a plurality of pores, And a protective layer provided on the electromagnetic wave shielding layer.

According to an embodiment of the present invention, a part of the conductive nanofiber web may be impregnated in the conductive adhesive layer on the basis of the thickness direction, or the entire conductive nanofiber web may be impregnated in the conductive adhesive layer.

Further, it may further include a first release film disposed under the electromagnetic wave shielding layer and a second release film disposed over the protection layer.

The conductive nanofibers may include a supporting fiber portion, a surface coating layer coated on the outer surface of the supporting fiber portion, and a conductive portion covering the entire outer surface of the surface coating layer, or may include a supporting fiber portion and a part or whole of the supporting fiber portion When the conductive part coat only a part of the surface coating layer or the outside of the supporting fiber part, the conductive part may include a region where the conductive nanofibers intersect.

The conductive nanofiber web may include conductive nanofibers and non-conductive nanofibers. The conductive nanofibrous web may include the conductive nanofibers to a thickness of 1 to 80% of the total thickness of the conductive nanofiber web, And may include malleable nanofibers.

When a part of the conductive nanofiber web is impregnated into the conductive adhesive layer, the conductive nanofiber web portion having a thickness of 50 to 85% of the total thickness of the conductive nanofiber web may be positioned in the conductive adhesive layer, The average thickness of the conductive adhesive layer portion not impregnated with the fibrous web is 3 to 12 占 퐉, and more preferably, the conductive nanofiber web is partially impregnated in the conductive adhesive layer so as to satisfy both of these conditions. Alternatively, when the entire conductive nanofiber web is impregnated into the conductive adhesive layer, the conductive nanofiber web may be impregnated on one surface of the conductive adhesive layer or disposed so as not to be offset to any one surface.

Also, a part of the conductive nanofiber web is impregnated into the conductive adhesive layer on the basis of the thickness direction, and a conductive adhesive layer is disposed on the lower surface of the electromagnetic shielding layer. At least a part of the conductive nanofiber web And the exposed area of the conductive nanofiber web may be 5 to 30% of the total area of the lower surface of the conductive nanofiber web.

The lower surface of the electromagnetic wave shielding layer may have a surface roughness (Ra) of 0.1 to 2 탆.

The conductive nanofibers may have a diameter of 5 mu m or less and the conductive nanofiber web may have an average pore size of 0.1 to 15 mu m, a thickness of 5 to 35 mu m and a basis weight of 4 to 150 g / m < 2 >.

The conductive adhesive layer may be formed of a tacky component containing at least one organic compound selected from the group consisting of acrylic, silicone, urethane, polyester, polyolefin, vinyl chloride, vinyl acetate, (Al), copper (Cu), silver (Ag), zinc (Zn), palladium (Pd), titanium (Ti), zirconium (Zr), indium (In), germanium (Ge) , At least one metal filler selected from the group consisting of gold (Au), iron (Fe) and alloys thereof, at least one conductive carbon-based filler selected from the group consisting of nickel-graphite, carbon black, carbon fiber and graphite One or more fillers may be included.

The conductive adhesive layer may include an adhesive component and a conductive filler having a glass transition temperature of -20 캜 to 30 캜.

Also, the conductive adhesive layer may include an adhesive component having an acid value of 30 to 300 mgKOH / g and a conductive filler.

Also, the conductive nanofiber web may have an elongation of 15 to 50%, and a surface resistance at a 15% elongation in any one direction may be 2? Or less.

The conductive nanofiber web may have a tensile strength of 20 N / mm 2 or more and a surface resistance of 50 m? Or less.

In addition, the supporting fiber portion may be formed of a material selected from the group consisting of polyurethane, polyethylene, polypropylene, polystylene, polyvinylalcohol, polymethyl methacrylate, polylactic acid ), Polyethylene oxide, polyvinyl acetate, polyacrylic acid, polycaprolactone, polyacrylonitrile, polyvinylpyrrolidone, polyvinyl chloride polyvinylchloride, polycarbonate, polycarbonate, polyetherimide, polyesthersulphone, polybenzimidazole, polyethylene terephthalate, polybutylene terephthalate, and fluorine-based compounds. And at least one selected from the group consisting of aluminum, nickel, copper, silver, gold, chromium , Platinum, and a titanium alloy.

The present invention also provides a method for preparing a conductive nanofiber web, comprising: preparing a conductive nanofiber web; Forming a protective layer on one surface of the conductive nanofiber web and forming a conductive adhesive layer on the other surface of the conductive nanofiber web, and applying a predetermined pressure so that a part of the conductive nanofiber web is impregnated into the conductive adhesive layer before compression The present invention provides a method of manufacturing an EMI shielding film.

According to an embodiment of the present invention, the step of preparing the conductive nanofiber web may include the steps of preparing a nanofiber web from a plurality of supporting fibers formed through electrospinning, and forming a conductive part on all or a part of the supporting fibers . ≪ / RTI >

Further, the present invention provides an electromagnetic wave shielding type circuit board comprising a circuit board on which at least one chip is mounted, and an EMI shielding film according to the present invention provided on the circuit board so as to cover at least the upper surface of the chip .

Further, the present invention provides an electronic apparatus having the above electromagnetic wave shielding type circuit board.

Hereinafter, terms used in the present invention will be described.

The terms "upper "," upper ", and "lower" of any layer used in the present invention include both cases in which the layers are directly opposed to the layer or indirectly formed after one or more other layers are inserted For example, the term "B layer provided on the A layer" means that both the A layer and the B layer face each other or the third C layer is formed between the A layer and the B layer.

Since the EMI shielding film according to the present invention has excellent flexibility, it can be adhered so that it is completely adhered even on a surface having a curvature or a step difference, and the deterioration or deterioration of the electromagnetic wave shielding performance can be prevented. Accordingly, the EMI shielding film can be widely applied to various types of chips having a step or a substrate on which such a chip is mounted.

1 is a cross-sectional view of an EMI shielding film according to an embodiment of the present invention.
FIG. 2 is a partial enlarged view of the nanofiber forming the conductive nanofiber web of FIG. 1 along the XX 'boundary. FIG.
3 is a schematic cross-sectional view of the electromagnetic wave shielding layer of FIG.
4 is a cross-sectional view of an EMI shielding film according to an embodiment of the present invention.
5 is a cross-sectional view of an EMI shielding film according to an embodiment of the present invention.
6 is a cross-sectional view of a circuit board having an EMI shielding film according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art to which the present invention pertains. The size of each structure disclosed in the drawings is only an example for facilitating understanding of the present invention, and the present invention is not limited to the size of each structure and the size ratio between the structures disclosed in the drawings.

1 to 3, an EMI shielding film 100 according to an embodiment of the present invention includes an electromagnetic wave shielding layer 20 and a protection layer 30 provided on the electromagnetic wave shielding layer 20 A first release film 10 disposed under the electromagnetic wave shielding layer and a second release film 40 disposed on the protection layer 30.

First, the electromagnetic wave shielding layer 20 includes a porous conductive nanofiber web 21 and a conductive adhesive layer 22.

The conductive nanofiber web 21 is formed such that a plurality of nanofibers including the conductive nanofibers 21a and 21b form a three-dimensional network to form a plurality of pores. Since the conductive fiber web 21 has a three-dimensional network structure and contains a plurality of pores therein, it is advantageous for the EMI shielding film to exhibit electromagnetic shielding performance and lightweight, compressibility and flexibility. . A part of the plurality of pores may be impregnated with a part of the conductive adhesive layer 22 to be described later. Through this, the adjacent conductive nanofibers 21a and 21b are further electrically connected to each other to exhibit an improved electromagnetic wave shielding effect Can be advantageous.

In addition, the conductive nanofiber web 21 may have a thickness of 5 to 35 탆, more preferably 6 to 25 탆, and still more preferably 8 to 18 탆. The basis weight may be 4 to 150 g / m 2, more preferably 10 to 120 g / m 2, and still more preferably 20 to 100 g / m 2. If the thickness is less than 5 占 퐉, there is a fear of handling and workability deterioration due to an excessively thin thickness, and a sufficient shielding ratio can not be exhibited to a desired level. Further, there is a fear that the elongation and shrinkage characteristics may decrease as the mechanical strength is lowered. If the thickness exceeds 35 탆, the flexibility may be insufficient and the adhesion to the curved surface of the adherend may deteriorate. If the basis weight is less than 4 g / m < 2 >, there is a risk of handling and workability deterioration, a decrease in elongation and shrinkage characteristics due to a decrease in mechanical strength, and a damage or breakage of the conductive fiber web when adhered to a stepped surface. In addition, if the basis weight exceeds 150 g / m < 2 >, it may be difficult to achieve the desired effects of the invention, such as lack of flexibility and adherence to the curved surface of the adherend.

In addition, the conductive nanofiber web 21 may have an average pore size of 0.1 to 15 탆, more preferably 0.2 to 5 탆, and still more preferably 0.5 to 2 탆. If the average pore size is less than 0.1 탆, the conductive adhesive layer described later is difficult to permeate into the conductive nanofiber web, so that the conductive adhesive layer is realized, but it is difficult to expose a part of the surface of the conductive nanofiber web to the desired level. In addition, there may be a case where the conductive part is excessively formed in the nanofiber web to reduce the pore size. In this case, there is a fear that the extensibility of the stretch and shrinkage is remarkably reduced and the adhesion force is reduced on the curved surface. There is a significant reduction in the risk. Alternatively, the average pore size of the nanofiber web itself may be small before the conductive part is formed. In this case, the conductive part may not be formed in the nanofiber web, but may be formed only on the surface, so that the desired shielding ratio may not be achieved. In addition, if the average pore size exceeds 15 mu m, the shielding rate may significantly decrease, and the object of the present invention may be difficult to achieve.

The conductive nanofiber web 21 may be formed of a plurality of nanofibers including all or a part of the conductive nanofibers 21a and 21b. In this case, the plurality of nanofibers may be formed of conductive nano- Fibers 21 and 21b, or unlike FIG. 3, some of the plurality of nanofibers may be conductive nanofibers 21a and 21b, and the remainder may include non-conductive nanofibers.

When only a part of the plurality of nanofibers includes the conductive nanofibers 21a and 21b, the conductive nanofibrous web is formed by mixing the conductive nanofibers 21a and 21b and the non-conductive nanofibers regardless of the positions in the conductive nanofiber web Lt; / RTI > 4, the conductive nanofibrous web 21 'has a first portion formed by including the conductive nanofibers 21'a to a predetermined thickness in the thickness direction from one surface thereof, as shown in FIG. 4, (A) and a second portion (B) formed by including the non-conductive nanofibers (21'b) in the remaining portion in the thickness direction. The conductive nanofiber web 21 'as shown in FIG. 4 may be formed as the second portion B including the non-conductive nanofibers 21'b as compared to the conductive nanofiber web 21 as shown in FIG. 2 Can be advantageous in expressing more improved flexibility, adhesion, compressibility and light weight. Preferably, the conductive nanofibers may include 1 to 80% of the total thickness of the conductive nanofiber web 21 ', and the remaining thickness may include non-conductive nanofibers. If the thickness of the conductive nanofiber web, ie, the first portion (A), which is one example, is less than 1% of the total thickness of the conductive nanofiber web, the shielding rate may be significantly reduced, If it exceeds 80%, the shielding ratio is increased but it may be difficult to attain the stretching property to the desired level.

The conductive nanofibers 21a, 21b, and 21'a may be nanofibers formed of a conductive polymer compound, or may be nanofibers formed of a conductive polymer compound. Alternatively, the conductive nanofibers 21a, And a conductive part that partially or entirely covers the outside of the supporting fiber part.

In the case of the nanofiber formed of the conductive polymer compound, the nanofiber may be one that has been spun using a known conductive polymer compound as a fiber-forming component. Further, as another example of the conductive nano fibers are shown in Fig supporting fiber portion (21a ₁₎ and one a nanofiber having a conductive part (21a ₂₎ for covering the outside of the support fiber portion (21a ₁₎ At this time, the conductive part 21a ₂ may be covered with a part or the whole of the outside of the supporting fiber part 21a ₁ . Although not shown in FIG. 2, a surface coating layer (not shown) may further be provided between the supporting fiber portion 21a ₁ and the conductive portion 21a _{2. In} this case, the conductive portion 21a ₂ may be formed on the surface It may be in a form of covering the outside of the coating layer. The surface coating layer has an advantage that the nanofiber web can have improved tensile strength, elongation and shrinkage characteristics, easiness of operation in the conductive part forming process, processability, and bonding strength between the conductive part and the supporting fiber part. When the conductive part 21a ₂ covers only a part of the surface coating layer or the outside of the supporting fiber part, the conductive part 21a ₂ may include a region where the conductive nanofibers 21a and 21b intersect, This has the advantage that the tensile strength and the shielding performance can be improved at the same time in the case where the conductive part is formed only in a region where the conductive nanofibers are not crossed.

More specifically, assuming that the conductive nanofibers 21a are nanofibers having conductive portions 21a ₂ covering the outside of the supporting fiber portion 21a ₁ as shown in FIG. 2, May be formed by assembling conductive nanofibers separately prepared so as to have a supporting fiber portion and a conductive portion. Alternatively, the nanofiber web may be first fabricated, and then a conductive part may be formed on the outer surface of the supporting fiber part, which is a nanofiber constituting the manufactured nanofiber web. In addition, the nanofiber web may further include a surface coating layer on the surface of the supporting fiber portion forming the nanofiber web before the conductive portion is provided on the nanofiber web.

The average diameter of the conductive nanofibers 21a may be 5 占 퐉 or less, more preferably 3 占 퐉 or less, and even more preferably 0.2 to 1.5 占 퐉 or less. Through this, it is possible to achieve excellent shielding efficiency, It is advantageous to secure. In addition, the support fiber portion 21a ₁ may have an average diameter of 2 탆 or less, more preferably 1 탆 or less, and even more preferably 10 to 800 nm, The workability and handling characteristics for forming the conductive part can be excellent, and mechanical strength can be secured, which is advantageous for achieving the object of the present invention.

The supporting fiber portion 21a ₁ may be formed of a material such as polyurethane, polyethylene, polypropylene, polystylene, polyvinylalcohol, polymethyl methacrylate, poly Polylactic acid, polyethyleneoxide, polyvinyl acetate, polyacrylic acid, polycaprolactone, polyacrylonitrile, polyvinylpyrrolidone, polyvinylpyrrolidone, polyvinylpyrrolidone, , Polyvinylchloride, polycarbonate, polycarbonate, polyetherimide, polyesthersulphone, polybenzimidazole, polyethylene terephthalate, polybutylene terephthalate, and fluorine-based compounds A non-conductive polymer compound selected from the group consisting of , Without limitation, it can be used without conventional in the case of polymers which can be used as a fiber compound limitation, placed out of the availability of the electrically conductive high molecular compound with the fiber-forming component.

The conductive portion 21b may be formed of at least one metal selected from the group consisting of aluminum, nickel, copper, silver, gold, chromium, platinum, and titanium alloys. The thickness of the conductive portion 21b may be 0.1 to 3 占 퐉, more preferably 0.1 to 2 占 퐉, and still more preferably 0.3 to 1 占 퐉. To achieve the object of the present invention, Can be more advantageous. For example, the conductive portion 21b may have a three-layer structure of a first nickel layer / a copper layer / a second nickel layer, wherein each of the first nickel layer and the second nickel layer has a thickness of 50 to 200 nm , And the copper layer may have a thickness of 200 to 500 nm, but is not limited thereto.

The surface coating layer (not shown) further provided on the outer surface of the supporting fiber portion 21a of the conductive nanofibers 21a having the conductive portion 21b is made of a nanofiber web It is possible to improve the bonding strength of the contact point between the supporting fiber portion and the supporting fiber portion, to prevent various troubles in the process of forming the conductive portion 21b, to improve the mechanical strength and to maintain the shape completely, There is an advantage in that the adhesion can be improved and the shielding ratio can be improved more than when the chip is mounted on a circuit board having a large stepped chip. Further, the bonding strength between the supporting fiber portion and the conductive portion can be further improved. The thickness of the surface coating layer may be 50 to 500 nm. If the thickness is less than 50 nm, the effect of the surface coating layer may be insignificant. If the thickness of the surface coating layer is more than 500 nm, It may be difficult to achieve the desired effect of the present invention, for example, it may be changed and the elasticity may be reduced. The material of the surface coating layer and various troubles that occur in the process of forming the conductive part will be described in detail in a manufacturing process to be described later.

Next, the conductive adhesive layer 22 forming the electromagnetic wave shielding layer 20 together with the above-described conductive nanofiber webs 21 and 21 'will be described. The conductive adhesive layer 22 serves to attach the EMI shielding film to the adherend surface. Further, the conductive nanofibers 21a, 21b and 21'a, which form pores, exhibit a function of further improving electrical connectivity between the conductive nanofibers 21a, 21b and 21'a.

The electromagnetic wave shielding layer 20 may be formed by impregnating part or all of the conductive nanofiber webs 21 and 21 'in the conductive adhesive layer 22. Specifically, a part of the conductive nanofiber webs 21 and 21 'may be impregnated into the conductive adhesive layer 22 based on the thickness direction. In this case, 50 to 85% of the total thickness of the conductive nanofiber webs 21 and 21 'may be located in the conductive adhesive layer 22 or may be the same as the thickness of the conductive adhesive layer 22 that is not impregnated with the conductive nanofiber webs 21 and 21' The average thickness of the portion 22 (P in Fig. 2) may be 3 to 12 mu m. Alternatively, the entire conductive nanofiber webs 21 and 21 'may be impregnated in the conductive adhesive layer 22. In this case, the conductive nanofibrous webs 21 and 21 'may be impregnated on one surface of the conductive adhesive layer 22 or may be impregnated on the center portion of the conductive adhesive layer 22 without being shifted to any one surface. have.

3, a part of the conductive nanofiber webs 21 and 21 'is impregnated into the conductive adhesive layer 22 with respect to the thickness direction, A second portion Q as a portion in which the conductive nanofiber webs 21 and 21 'are impregnated and a second portion Q in which the conductive nanofiber webs 21 and 21' And may include a first portion P connected to the second portion Q, At this time, the first portion P is not formed to cover the entire lower surface of the conductive nanofiber web 21, and a first portion P is formed such that a part of the conductive nanofiber web 21 is exposed. . At this time, in order to expose a part of the conductive nanofiber web 21 to a desired level, the first portion P of the conductive adhesive layer 22, that is, the thickness of the portion not impregnated with the conductive nanofiber web in the conductive adhesive layer is And preferably the average thickness d of the first portion P may be 3 to 12 占 퐉. If the average thickness of the first portion (P) is less than 3 mu m, the area of the exposed conductive nanofibrous web increases, and the adhesion and adhesion of the EMI shielding film may be lowered on the surface of the conductive nanofibrous web. If the average thickness of the first portion P exceeds 12 μm, the area of the exposed conductive nanofibrous web is too small or not exposed, so that it may be difficult to improve the desired electromagnetic wave shielding performance.

The conductive adhesive layer 22 may have a thickness of 5 to 20 μm, more preferably 5 to 15 μm, and still more preferably 6 to 10 μm. In this case, the average thickness of the first portion (P) More preferably 3 to 10 mu m, and more preferably 4 to 7 mu m. As a result, excellent shielding characteristics and an area of the exposed conductive nanofiber web are achieved at an appropriate level, And the present invention is advantageous in achieving the desired effect.

In addition, 50 to 85%, more preferably 60 to 85% of the total thickness of the conductive fiber web may be located in the conductive adhesive layer. That is, the average thickness of the second portion Q may be 50 to 85% of the total thickness of the conductive nanofiber web. If the average thickness of the second portion Q exceeds 85% of the total thickness of the conductive nanofibrous web, adhesion of the conductive nanofibrous web to the protective layer formed on the opposite surface may be interfered, peeling, peeling may occur. In addition, there is a possibility that the elongation and shrinkage characteristics of the electromagnetic wave shielding layer may be deteriorated, and there is a fear that adhesion and shielding efficiency may be lowered when applied to a circuit board on which a chip having a large step is mounted. In addition, when the average thickness of the second portion Q is less than 50% of the total thickness of the conductive nanofibrous web, there is a fear of deterioration in adhesion and shielding efficiency and deterioration of peel strength when applied to a circuit board having a chip with a large step.

The conductive nanofibrous webs 21 and 21 'are impregnated in the conductive adhesive layer 22. The conductive nanofibrous webs 21 and 21' are impregnated into the conductive adhesive layer 22. Layer may be filled, which may have the advantage of improving the connectivity between the conductive nanofibers. At this time, the conductive adhesive layer may include an independent layer portion covering the entire surface of one side or both sides of the conductive nanofiber web with a predetermined thickness. In this case, there is an advantage that the adhesion between the conductive nanofiber web and the adherend surface can be further improved although the expansion and contraction characteristics may be lowered. In addition, through the independent layer portion of the conductive adhesive layer provided on both sides, the bonding force with the adhered surface such as the electronic component on one side and the bonding force with the protective layer on the other side can be improved. In addition, when a separate layer portion with a predetermined thickness is provided on both sides, the separate layer portion covers a part of the both surfaces of the conductive nanofibrous web so that a part of the surface of the conductive nanofibrous web can be exposed. In this case, the exposed surface of the conductive nanofiber web can increase the surface roughness of the surface, and in this case, the advantage of being able to further improve the bonding force between the surface of the electronic component and the protective layer due to the anchor effect .

The conductive adhesive layer 22 may be formed through a conductive adhesive composition including an adhesive component 22b and a conductive filler 22a. The adhesive component 22b may be used without limitation in the case of the adhesive component included in the known electromagnetic wave shielding film. Examples of the adhesive component 22b include acrylic, silicone, polyurethane, polyester, polyolefin, , A vinyl acetate-based compound, and an epoxy-based compound. However, an acrylic or polyurethane based organic compound may be preferably used so as to have a compression property and an elastic property so that the solidified adhesive component is not broken or broken when the EMI shielding film is squeezed. Meanwhile, when the adhesive component 22b is a curable organic compound, the conductive adhesive composition may further include a curing agent capable of curing the adhesive composition. The curing agent may be a known curing agent in consideration of the specific kind of the curable organic compound as the adhesive component to be selected. Therefore, the detailed description of the present invention will be omitted. When the adhesive component is a curable component, the curing agent may be included in an amount of 0.05 to 10 parts by weight based on 100 parts by weight of the adhesive component, but is not limited thereto.

According to a preferred embodiment of the present invention, the adhesive component 22b may have a glass transition temperature of -60 占 폚 to 130 占 폚, more preferably -20 占 폚 to 30 占 폚. If the glass transition temperature is less than -60 ° C, the conductive adhesive layer may melt due to the heat generated in the chip, which is attached to the chip mounted circuit substrate, which is one example of the later- There is a possibility that a problem such as the removal of the shielding film may occur, and it may be difficult to maintain a uniform adhesive layer on the film. In addition, if the glass transition temperature is higher than 130 캜, a high temperature condition is required when the EMI shielding film is adhered to the adherend surface, thereby damaging the chip or the circuit board, which is one example of the adherend surface, There is a possibility that the process temperature and the process time become long, and when the process conditions are insufficient, complete close contact with the curved surface may not be achieved.

The adhesive component 22b may have an acid value of 10 to 500 mgKOH / g, more preferably 30 to 300 mgKOH / g. Means the number of mg of potassium hydroxide necessary for neutralizing free fatty acid, resin acid, and the like contained in 1 g of acid glutamate in the present invention. Specifically, the acid value may be influenced by a functional group contained in the organic compound, for example, a carboxyl group or a sulfonic acid group, and the acid value may be closer to zero as the functional group is absent. More specifically, when the tacky component is an acrylic organic compound, it may be a polymer reacted with acrylic monomers. If acrylic acid is contained as the acrylic monomer, the acid value may be determined according to the acrylic acid content. If the acid value of the adhesive component is less than 10 mgKOH / g, the adhesion with the surface to be adhered decreases, and the ground function may become incomplete. If the acid value exceeds 500 mgKOH / g, the corrosion of the circuit board or the chip may be remarkably increased, and the adhesion may gradually decrease due to side reaction caused by corrosion, which may significantly reduce the durability.

The conductive filler 22a may be formed of at least one selected from the group consisting of Ni, Al, Cu, Ag, Zn, Pd, Ti, Zr, At least one metal filler selected from the group consisting of In, Ge, Sn, Au, Fe and alloys thereof, nickel-graphite, carbon black, carbon fiber and graphite And one or more conductive carbon-based fillers selected from the group consisting of the above-mentioned conductive carbon-based fillers. The conductive filler may be spherical or irregular granular or branched and may be suitably modified according to the purpose. In addition, the conductive filler 22a may have an average particle diameter of 1 to 8 탆, which can be suitably changed in consideration of the average pore size of the conductive fiber web described above, so that the present invention is not particularly limited thereto. The conductive filler 22a may be included in an amount of 5 to 200 parts by weight based on 100 parts by weight of the adhesive component 22b. If the conductive filler is included in an amount of less than 5 parts by weight, it may be difficult to exhibit the desired level of conductivity If it exceeds 200 parts by weight, flexibility and adhesion may be decreased.

The conductive adhesive composition may further include a ceramic filler, a tackifier, and a solvent in addition to the adhesive component, the conductive filler and the curing agent.

The ceramic filler is for improving the resin flow and cohesion of the adhesive layer and can be used without limitation in the case of a ceramic filler applied to a pressure-sensitive adhesive composition. For example, the ceramic filler may be at least one selected from the group consisting of tin oxide, indium oxide, silicon carbide, silica, alumina, zirconium carbide, glass and titanium carbide. In this case, the ceramic filler may be included in an amount of 0.1 to 5 parts by weight based on 100 parts by weight of the above-mentioned adhesive component.

In addition, since the tackifier is primarily bonded to the surface to be bonded through hot-melt or full curing, the tackifier is responsible for imparting initial tackiness at the time of bonding. As the tackifier, known components can be used. For example, a modified silicone, a rosin-based resin, a petroleum resin, a wax, or the like can be used. The tackifier may be included in an amount of 3 to 70 parts by weight based on 100 parts by weight of the adhesive component.

The solvent may be selected from known solvents such as water and an organic solvent in consideration of the selected adhesive component and additives.

The conductive adhesive composition may have a viscosity of 100 to 5,000 cps, more preferably 500 to 2,000 cps at 25 ° C. If the viscosity is less than 100 cps at 25 캜, the formation of the adhesive layer may become incomplete. If the viscosity exceeds 5,000 cps, the conductive adhesive layer may be difficult to penetrate into the conductive nanofibrous web through a pressing process described later, It may be difficult to expose a part of the conductive nanofiber web surface.

According to an embodiment of the present invention, the electromagnetic wave shielding layer 20 including the conductive nanofiber webs 21 and 21 'and the conductive adhesive layer 22 has the conductive nanofiber webs 21 and 21' (N in Fig. 3), which may be one surface of the electromagnetic wave shielding layer 20 facing the first release film 10 in Fig. Since the conductive nanofiber webs 21 and 21 'are partially exposed, it is possible to improve the grounding function when attached to the adherend surface, and to exhibit better electromagnetic wave shielding performance.

At this time, the degree of exposure of the exposed conductive nanofiber webs 21 and 21 'is 5 to 30% based on the total area of one surface of the exposed conductive nanofiber webs 21 and 21', more preferably, An area of 5 to 10% can be exposed. Here, the total area refers to the surface area when the lower surface of the conductive nanofibrous web is projected in two dimensions. In addition, the area of the exposed portion of the exposed conductive nanofiber web 21, 21 'also means the surface area of the corresponding region when the exposed portion is projected in two dimensions, and the surface area of the actual nanofibers contained in the exposed portion It does not mean anything. If the exposure level is less than 5%, it may be difficult to expect the electromagnetic shielding performance to be improved to the desired level. If the exposure level exceeds 30%, the adherence to the adhesion surface The electromagnetic shielding performance may be lowered considerably due to the lowering of the adhesion, the lowering of the adhesion, and the lowering of the electrical connectivity between the conductive fibers.

The lower surface of the electromagnetic wave shielding layer 20 from which part of the conductive nanofiber webs 21 and 21 'is drawn may have a surface roughness Ra of 0.1 to 2 탆, more preferably 0.2 to 1 탆. At this time, the lower surface of the electromagnetic wave shielding layer 20 serving as the measurement area of the surface roughness may be a lower surface defined in the region corresponding to the conductive nanofiber web. That is, if the electromagnetic wave shielding layer is formed in an area larger than the area of one side of the conductive nanofiber web, the surface roughness is not determined based on the entire surface of the electromagnetic wave shielding layer, Means a value measured based on an area. If the surface roughness (Ra) is less than 0.1 탆, there may be a problem that the ground function is deteriorated, and when the surface roughness (Ra) is more than 2 탆, adhesion with the metal adherend may become incomplete.

In addition, when the exposed degree of the conductive nanofiber web and the surface roughness of the lower surface of the electric wave shielding layer in which the conductive nanofiber web is exposed are simultaneously satisfied, it is possible to simultaneously exhibit the electromagnetic shielding performance and the adhesive property.

In addition, the portion of the exposed conductive nanofiber web 21 may be part of the conductive nanofibers forming the conductive nanofiber web and / or the web in which these conductive nanofibers are integrated. The exposed portion of the conductive nanofiber web 21 may be exposed only to a part of the lower surface of the electromagnetic wave shielding layer 20 or may be uniformly exposed to various portions of the lower surface of the electromagnetic shielding layer 20 have.

The surface resistivity of one surface of the electromagnetic wave shielding layer 20 or 20 'implemented to expose at least a part of one surface of the conductive nanofiber web 21 or 21' is 10 Ω / sq or less, more preferably 10 mΩ / 500 m? / Sq, and more preferably 10 m? / Sq to 300 m? / Sq. If the surface resistance of one side of the electromagnetic shielding layer exposed to the conductive nanofiber web is more than 10? / Sq, it may be difficult to improve the grounding performance and shielding performance according to the exposure of the conductive nanofiber web. It can be difficult to achieve.

In addition, the conductive nanofiber webs 21 and 21 'preferably have elongation at 25 ° C to 160 ° C of 10-200%, more preferably 15-100%, even more preferably 15-50% 25% to 50%, and thus excellent flexibility can be exhibited. In addition, the surface resistance can be 2? / Sq or less at 15% elongation in the uniaxial direction, and the surface resistance at 25% elongation can be 50? / Sq or less. That is, despite the increase in elongation, it is possible to prevent the increase of surface resistance by preventing or minimizing the increase of the surface resistance, and at the same time, by increasing the mechanical strength to withstand the elongation, And can exhibit improved electromagnetic wave shielding performance by elongation generated in the process of adhesion and adhesion.

The conductive nanofiber webs 21 and 21 'may have a tensile strength of 20 N / mm 2 or more, more preferably 40 N / mm 2 or more, and further preferably 60 to 100 N / mm 2. If the tensile strength is less than 20 N / mm < 2 >, it is difficult to exhibit sufficient mechanical strength. However, it is preferable that the tensile strength is 100 N / mm 2 or less. If it exceeds 100 N / mm 2, the elongation and shrinkage characteristics are remarkably reduced, and it may be difficult to adhere to the stepped chip.

On the other hand, the above-described electromagnetic wave shielding layers 20 and 20 "may be electrically isotropic or anisotropic.

Next, the protective layer 30 disposed on the electromagnetic wave shielding layer 20 will be described.

The protective layer 30 is a layer for protecting the electromagnetic wave shielding layer 20 and may be used without limitation in a known protective layer provided in the electromagnetic wave shielding film. As a non-limiting example, it may include at least one polymer compound selected from the group consisting of polyimide-based, polyamide-based, polyamideimide-based, polyacryl-based and polyester-based ones. However, it may preferably include a urethane-based polymer compound, which has a low thermal shrinkage characteristic after firing and has a high flexibility, so that it can be adhered to a stepped surface without peeling.

The thickness of the protective layer 30 may be in the range of 2 to 30 占 퐉. When the thickness of the protective layer 30 is less than 2 占 퐉, the thickness of the protective layer 30 may be thinner than 30 占 퐉 There is a fear that the flexibility is lowered and the adhesion to the stepped surface is lowered. At this time, the protective layer 30 may have an adhesion of 1000 gf / inch or more and an electrical resistance of 1 x 10 ¹² ? Or more.

On the other hand, the protective layer 30 may further include a colorant or a pigment so as to be transparent or to exhibit a specific color for improving workability and visibility. For example, the specific color may be black, and the protective layer 30 may further include carbon black and / or black pigment.

In addition, the protective layer 30 may be formed with a pattern for the other surface of the opposite surface of the electromagnetic wave shielding layer 20 to ensure and improve the visibility. The pattern is advantageous in improving visibility and workability by inducing scattering of light and diffusion of light incident on the protective layer 30 to increase haze. At this time, the pattern may be transferred and formed by a reverse-phase pattern to the pattern formed on one side of the second release film 40 described later.

In addition, the protective layer 30 may further include an insulator. The insulator may further include at least one selected from a ceramic insulator and a plastic insulator. The protection layer 30 is easy to exhibit electrical insulation through the insulator, thereby preventing unintentional conduction between parts through the EMI shielding film and preventing a short circuit due to the EMI shielding film.

5, the protective layer 30 'may have a laminated structure of a first layer 31 and a second layer 32, wherein the first layer 31 May have a thickness of 2 to 20 탆, and the second layer 32 may have a thickness of 2 to 20 탆, but the present invention is not limited thereto. The thicknesses of the first layer 31 and the second layer 32 may be the same or different. If the protective layer 30 'has a laminated structure, the second layer 32 may further include a colorant or pigment so as to exhibit a specific color for improving workability and visibility. For example, the specific color may be black.

Next, the first release film 10 which can be further disposed below the electromagnetic wave shielding layer 20 will be described. The first release film 10 serves as a protective film for protecting the electromagnetic wave shielding layer 20 until the electromagnetic wave shielding layer 20 adheres to the adherend surface, that is, the upper surface of the circuit board on which the chip is mounted do. The first release film 10 can be used without limitation regardless of material, thickness, etc. in the case of a known release film which can protect a predetermined layer and can be easily peeled off from the predetermined layer when appropriate. However, the first release film 10 may be a transparent film, preferably a matte transparent film. More specifically, for example, a PET film, a PET film coated with a silicone release coating, a non-silicone based matte PET film and the like may be used.

The first release film 10 may have a thickness of 20 to 50 탆, but is not limited thereto.

Next, the second release film 40, which can be further disposed on the above-described protective layer 30, will be described. The second release film 40 may be a known release film as a film for protecting the protection layer 30 and the electromagnetic wave shielding layer 20 until the EMI shielding film according to the present invention is applied to the adherend The present invention is not particularly limited to this.

On the other hand, a pattern may be formed on one surface of the second release film 40, and one surface of the second release film 40 may be disposed so as to face the protective layer 30. The protective layer 30 formed on the patterned second release film 40 can be formed by transferring the pattern of the reversed phase on one side of the protective layer 30 due to the pattern, Can be matted.

In addition, the thickness of the second release film 40 is preferably 5 to 100 占 퐉, and more preferably 20 to 75 占 퐉.

The adhesive layer or the adhesive layer may be provided with an electromagnetic wave shielding layer having a conductive filler or a conductive adhesive layer provided between the layers of the EMI shielding film according to the present invention. But are not limited thereto.

The above-mentioned EMI shielding film according to the present invention has a band gap of at least 10 dB, more preferably at least 20 dB, even more preferably at least 50 dB, more preferably at least 70 dB, even more preferably at least 100 dB , And even more preferably 120 dB, thereby enabling to exhibit improved EMI shielding performance. More specifically, the shielding ratio at 1.5 GHz may be 60 dB or more, more preferably 70 dB or more.

The EMI shielding film according to the present invention can be manufactured by a manufacturing method described below, but is not limited thereto. The manufacturing method described below assumes that the conductive adhesive layer penetrates only the inner portion of the conductive nanofiber web and the manufacturing method of the embodiment in which the conductive adhesive layer is formed so as to cover the inside and the outside of the conductive nanofiber web Known methods such as modifying the manufacturing method described below or impregnating the conductive nanofibrous web into the conductive adhesive composition can be suitably adopted, so that a detailed description thereof will be omitted.

A method of manufacturing an EMI shielding film according to the present invention includes the steps of preparing a conductive nanofiber web, forming a protective layer on one side of the conductive nanofibrous web, forming a conductive adhesive layer on the other side of the conductive nanofiber web, And applying a predetermined pressure such that a portion of the fibrous web is impregnated into the interior of the pre-press conductive adhesive layer.

First, a step of preparing a conductive nanofiber web will be described. The conductive nanofiber web may be prepared by a method of forming a nanofiber web through a conductive polymer compound. In the following description, however, an embodiment in which a separate conductive part is formed on the nanofiber web will be described.

The conductive nanofiber web may include a step of preparing a nanofiber web formed of a supporting fiber portion, and a step of forming a conductive portion on all or a part of the supporting fiber portion of the nanofiber web.

The nanofiber web formed of the supporting fiber portion is realized by electrospinning a spinning solution in which a fiber forming component is melted or dissolved. Voltage and air gap applied during electrospinning are determined by the kind of the specific fiber forming component, the average Diameter, and the like, and therefore the present invention is not particularly limited to this.

For example, the nanofiber web may be one obtained by heating and melting a thermoplastic resin such as an olefin-based, polyurethane-based or polyester-based resin, and then collecting it on a releasing paper by electrospinning using high-temperature steam. For example, when the fiber forming component is polyurethane, a shore hardness of 70 to 100 can be used. At this time, the supported fiber portion which is the nanofiber that is radiated may have an average diameter of 2 탆, more preferably 1 탆 or less, and even more preferably 50 nm to 0.8 탆. The collected nanofiber webs can then be subjected to a calender pressing process to remove inflating and improve tensile strength and thickness. The compression process may be performed by applying a pressure of 0.1 to 1 kgf / cm 2 at a temperature of 20 to 40 ° C. When calendering, the produced nanofiber web may have a pore size of 0.1 to 10 mu m, a tensile strength of 5 to 10 N / mm < 2 > and a thickness of 1 to 50 mu m.

Then, the nanofiber web may be further subjected to a pretreatment process to improve mechanical strength such as tensile strength. This can be advantageous in that it has sufficient mechanical strength required for performing a plating process or a sputtering process, which is one example of forming a conductive part to be described later. In particular, in the plating process, hydrogen gas can be generated by the oxidation-reduction reaction. If the bonding between the supporting fibers of the nanofiber is not stable, hydrogen gas generated is trapped in the inner space of the nanofiber web, There is a risk of formation. However, when the pretreatment process is performed, the trapping of the hydrogen gas or the degradation of the processability caused by the weak mechanical strength can be prevented as the bonding between the supporting fibers becomes stronger.

In addition, the shape of the nanofiber web can be deformed or compressed due to the weight of the conductive parts deposited during the sputtering process. In this case, since the specification of the nanofiber web designed in the beginning is changed during the process, There can be a difficult problem. However, when the pretreatment process is performed, the mechanical strength of the nanofiber web is improved, so that there is no fear of shape deformation and reduction in pore size caused by compressing the nanofiber web at the portion where the conductive portion is not deposited.

The pretreatment may be performed by treating the nanofiber web with a polymer solution for pretreatment followed by drying, wherein the polymer solution is a solution containing a known polymer compound having a binder property such as an acrylic compound or a urethane compound Or dispersions). In this case, the polymer solution may be in a state where the polymer compound is dissolved or dispersed in a solvent, for example, water, but is not limited thereto.

As a method of treating the nanofiber web with the polymer solution, a known coating method can be used and, for example, may be immersed.

The nanofiber web on which the polymer surface coating layer is formed after the polymer solution is treated and dried to cover the outside of the supporting fiber portion may have a tensile strength of 20 to 100 N / mm 2. The tensile strength is improved by about 1.5 to 10 times . In addition, the elongation may also be at least 20%.

Thereafter, the nanofiber web having the polymer coating layer may further be subjected to a calender pressing process for uniforming the thickness, improving the tensile strength, and controlling the thickness. The conditions include, for example, a temperature of from 0.1 to 1 kgf / cm 2 Lt; / RTI > The final thickness of the nanofiber web subjected to the pressing process may be 4 to 30 탆, more preferably 5 to 20 탆, still more preferably 7 to 15 탆, and a basis weight of 0.5 to 30 g / M < 2 >, more preferably from 8 to 11 g / m < 2 >. The elongation percentage may be 20% or more, more preferably 40% or more, more preferably 60% or more, and still more preferably 60 to 100%.

Thereafter, a step of forming a conductive portion on all or a part of the supporting fiber portion of the prepared nanofiber web can be performed.

A known method for forming the conductive part on the supporting fiber part of the nanofiber can be applied without limitation, for example, electroless plating or sputtering. When electroless plating is performed, it is advantageous to form a conductive part on the whole of the supporting fiber part of the nanofiber web.

The method for forming the conductive part through the electroless plating may be appropriately changed according to the purpose using a known electroless plating method. For example, in order to facilitate formation of the conductive part in the nanofiber web, The process can be carried out. For example, the conductive part may be formed by stacking three metal layers of a first nickel layer, a copper layer, and a second nickel layer. To this end, the nanofiber web may be sequentially subjected to nickel plating, copper plating, and nickel plating.

In addition, the sputtering is an advantageous method for forming the conductive nanofiber web as shown in FIG. 5 by forming the conductive nanofibers from one side of the nanofiber web to a predetermined height in the thickness direction. In the sputtering, a target metal component may be formed by using a known sputtering equipment to form a conductive part by a predetermined thickness from one surface and one side of the nanofiber web, and the part where the conductive part is formed achieves a desired shielding ratio, The non-formed portion has the advantage that the flexibility of the base material is maintained and can be more adhered to the stepped surface to be adhered more tightly.

The metal component may be Ag or Ni-Cu-Ni, but is not limited thereto.

Next, a step of forming a protective layer on one surface of the prepared conductive nanofiber web and forming a conductive adhesive layer on the other surface of the conductive nanofiber web.

First, a process of forming a protective layer will be described. A protective layer can be formed by treating the protective layer forming composition on one surface of the conductive fiber web. The composition for forming a protective layer may include a main polymer compound and a solvent for forming a protective layer, and may further include other pigments, pigments, insulators, etc. The main polymer compounds include polyimides, polyamides, Based polymer, a polyamide-imide-based polymer, a polyacryl-based polymer, and a polyester-based polymer. The solvent may be selected depending on the kind of the polymer compound to be selected, may be water or organic solvent, and the content may be varied so as to obtain an appropriate viscosity in consideration of the method of treatment.

The method in which the protective layer forming composition is treated on the conductive fiber web may be a known coating method, for example, a comma, a gravure, or the like.

Meanwhile, in the case of the laminated structure of the first layer and the second layer, the protective layer may be formed by first forming a first layer facing the conductive nanofibrous web, and then forming a second layer on the first layer. In this case, both the first layer and the second layer may have an insulating function, and the second layer may be a black insulating layer further comprising a black pigment.

Next, a step of forming a conductive adhesive layer on the other surface of the conductive nanofiber web before compression bonding will be described.

The pre-pressing conductive adhesive layer may be a solution having a conductive filler dispersed in a pressure-sensitive adhesive solution for a conductive adhesive solution, for example, an acrylic or urethane-based hot melt. The conductive adhesive solution may be coated on the conductive nano-fiber web surface to a predetermined thickness through a known coating method, and the coating method may be, for example, a comma or a gravure. The pressure-sensitive conductive adhesive layer implemented in layers through drying may have a thickness of 5 to 25 탆, but is not limited thereto.

Next, a step of applying a predetermined pressure so that a part of the conductive nanofiber web is impregnated into the conductive adhesive layer before compression bonding will be described.

A part of the conductive nanofibrous web is impregnated from a surface facing to the inside of the pre-compression conductive adhesive layer realized with a predetermined thickness to a predetermined thickness range through this step, Q) of the conductive nanofibrous web may be located inside the conductive nanofiber web, and the rest (the first portion, P of FIG. 2) may form a separate layer on the conductive nanofiber web. On the other hand, when an appropriate pressure is applied so that the average thickness d of the first portion P of the conductive adhesive layer is realized to an appropriate thickness, a part of the conductive nanofiber web may be exposed to the outside.

Meanwhile, in the above-described manufacturing method, a protective layer is formed on one side of the conductive nanofiber web, and a conductive adhesive layer is formed on the other side of the conductive nanofiber web, followed by pressing. However, the present invention is not limited thereto. It is possible to carry out a pressing process and then form a protective layer thereafter.

Thereafter, a process of providing a release film on each layer for protecting the protective layer and the conductive adhesive layer may be further performed on both sides of the EMI shielding film implemented by the above-described manufacturing method.

The EMI shielding film 100 implemented through the above-described manufacturing method may be mounted on the circuit board 200 on which the at least one chip 210 or 220 is mounted, as shown in FIG. 6, So that the electromagnetic shielding type circuit board 1000 can be realized. At this time, the EMI shielding film 100 according to the present invention can be adhered to an upper part of a chip or a circuit board with excellent adhesion due to excellent flexibility. The chips 210 and 220 and the circuit board 200 may be implemented by appropriately employing those well known in the field of electric and electronic technology, and the present invention is not limited thereto.

On the other hand, the shielding film 100 may be bonded to a circuit board after bonding. May have an adhesive property at room temperature, for example 80 gf / inch at 25 [deg.] C. After bonding, heat can be applied at a temperature of 120 to 160 ° C and a pressure of 0.1 to 0.6 Bar for 30 seconds to 2 minutes. At this time, the adhesive force may be 1000 gf / inch or more.

In addition, the electromagnetic shielding type circuit board 1000 described above is provided as a component of an electronic apparatus to implement an electronic apparatus, and the electronic apparatus is applicable to a battery such as a TV, a computer, a mobile electronic apparatus such as a mobile phone, And the present invention is not particularly limited to this.

The present invention will now be described more specifically with reference to the following examples. However, the following examples should not be construed as limiting the scope of the present invention, and should be construed to facilitate understanding of the present invention.

≪ Example 1 >

A polyurethane resin having a Shore hardness of 85 to 100 was melted at 220 占 폚 to prepare a spinning solution. The prepared spinning solution was applied through a conventional electrospinning device to a paper release sheet having a silicone surface treated at a temperature of 25 ° C and a RH of 60% under the conditions of an applied voltage of 20 kV, a distance of 20 cm from the current collector to the spinneret and a discharge rate per minute of 0.02 g / To give a nanofiber web having an average diameter of the supporting fiber portion of 700 nm. The obtained nanofiber web was subjected to primary calendering at a temperature of 30 DEG C and a pressure of 200 kPa to obtain a pressed nanofiber web having a three-dimensional network structure, a tensile strength of 15 N / mm < 2 >, a elongation of 80% .

Thereafter, as the pretreatment step, the pressed nanofiber web prepared in the aqueous dispersion containing about 15% by weight of the total weight of the aqueous dispersion is immersed in the hydroxy group-containing polyurethane polymer, and then dried to prepare a polyurethane polymer To form a nanofiber web having a tensile strength of 35 N / mm < 2 > and a elongation of 100% and a thickness of 18 [micro] m.

Then, secondary calendering was carried out under the same conditions as the primary calendering to prepare a nanofiber web having a final thickness of 15 탆 and a basis weight of 10 g / ㎡.

Electroless plating was performed to form a conductive part on the supporting fiber part of the prepared nanofiber web. Nickel electroless plating, copper electroless plating and nickel electroless plating were sequentially performed in order to form a conductive part having a nickel-copper-nickel three-layer structure. Before performing the electroless plating, the prepared nanofiber web was subjected to etching, pickling and conditioner processing according to known conditions, and electroless plating of the nanofiber web was performed. The three-layered nickel-copper-nickel structure of conductive portions sequentially formed had thicknesses of 100 nm, 300 nm and 100 nm, respectively, and had a total thickness of 500 nm. The developed conductive nanofiber web had a basis weight of 55 g / M < 2 > and a thickness of 17 mu m.

Thereafter, a first layer including a urethane resin and an acrylic resin was formed on one side of the conductive nanofiber web to a thickness of 2 탆, and then a black protective ink was gravure-coated on the primer to form a final layer having a thickness of 4 탆, Thereby forming a protective layer having a total thickness of 6 mu m. The black protective ink was prepared by adding carbon black having a particle size of 25 nm and silica having a particle size of 30 nm at a weight ratio of 1: 1 to an acrylate resin having excellent heat resistance and elongation properties, stirring the mixture, and dispersing the mixture using a bead mill. Was mixed with 20 wt%.

Thereafter, a conductive adhesive layer was prepared through the conductive adhesive composition prepared as follows. To prepare a conductive adhesive composition, 60 parts by weight of a solvent toluene was added to 100 parts by weight of a modified acryl-based component having an acid value of 120 mgKOH / g, a glass transition temperature of -20 占 폚 and a weight average molecular weight of 200,000 as an adhesive component , 3 parts by weight of an epoxy curing agent having a glycidyl group, 25 parts by weight of a nickel powder having an average particle diameter of 4 탆 and 80 parts by weight of a hot-melt urethane component were mixed to prepare a conductive adhesive composition having a viscosity of 1800 cps at 25 캜.

Thereafter, the prepared conductive adhesive composition at 25 캜 was treated on the other side of the conductive nanofiber web and dried to form a pre-compression conductive adhesive layer having a thickness of 12 탆.

Thereafter, a pressure was applied to the conductive adhesive layer before compression to permeate a part of the conductive adhesive layer into the conductive nanofiber web, thereby realizing an electromagnetic wave shielding layer. As a result, the average thickness of the first portion (P in Fig. 2) of the conductive adhesive layer was 7 mu m and the average thickness of the second portion of the conductive adhesive layer (Q in Fig. 2) %, And the surface of the conductive nanofiber web was exposed on the lower surface by about 6% of the total area of the lower surface of the conductive nanofiber web, and the surface roughness (Ra) of the lower surface was 0.5 탆. Then, a release film having thicknesses of 50 탆 and 25 탆 was laminated on the conductive adhesive layer and the protective layer, respectively, to produce an EMI shielding film.

≪ Examples 2 to 6 >

The thickness of the conductive adhesive layer before compression and the pressure at the time of compression were changed so that the ratio of the second portion Q of the conductive adhesive layer and the average of the first portion P of the conductive adhesive layer The EMI shielding film having the thickness and the area ratio of the conductive fiber web exposed on the lower surface of the electromagnetic shielding layer was implemented as shown in Table 1 below.

≪ Example 7 >

Except that the conductive fiber web was not exposed on the lower surface of the electromagnetic wave shielding layer to prepare an EMI shielding film as shown in Table 1 below.

<Experimental Example 1>

The following properties of the EMI shielding films according to Examples 1 to 6 and Comparative Example 1 were evaluated and are shown in Table 1 below.

1. Surface roughness measurement

The surface roughness (Ra) of the lower surface of the electromagnetic wave shielding layer where a part of the conductive fiber web was exposed was measured using a surface roughing machine.

2. Surface resistance

The surface resistance was measured with respect to the lower surface of the electromagnetic wave shielding layer where a part of the conductive fiber web was exposed and the average surface resistance value of the nine portions of the test piece was shown on the basis of the test piece having the surface resistance of 50 x 50 mm. In addition, the average value of the surface resistivity of the nine points of the specimen after stretching the specimen in one direction by about 15% is shown in the table.

3. Peel strength measurement

After removing the lower release film, it was bonded to a PCB substrate (solder resist, epoxy system) so that the conductive adhesive layer faces the substrate, and then bonded by hot press (140 ° C, 0.3Bar, 60 sec) A solder resist specimen with a width of 10 mm was prepared. The peeling strength of the shielding film was measured. The peel strength was 180 peel, the peeling speed was 50 mm / min, and the ten peeling strengths were measured after the bonding and the peeling strengths after the bonding. And the average value.

4. Adhesion evaluation

400 탆, 400 탆, 800 탆, and 400 탆, 400 탆, and 1000 탆, respectively, at intervals of 1 mm The specimens were bonded to each other by a hot press (140 ℃, 0.3Bar, 60 sec) process, with the adhesive adhesive layer of the shielding film on which the lower release film was removed. The prepared specimens were cut in the vertical direction to evaluate whether or not there was an excited portion of the shielding film on the cross section. The case where the excited portion was present was indicated as X, and the case where the excited portion was not present and adhered closely.

5. Measurement of electromagnetic wave shielding rate

The shielding rate at a frequency of 1.5 GHz was measured. After 10 measurements of shielding rate for 5 samples, the mean value was measured and shown.

Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Average thickness (占 퐉) of the conductive adhesive layer first portion (P) 7 4 3.2 2 10 12 13.5 (%) Of the second part thickness of the conductive adhesive layer among the total thickness of the conductive nanofibrous web 80 52 60 95 71 30 5 % Of exposed conductive fiber web area (%) 6 10 28 35 5 2 0 Surface roughness (탆) 0.5 0.5 1.8 2.8 0.3 0.2 &Lt; 0.1 Surface resistance (mΩ) 50 150 200 520 80 320 350 Surface resistance at 15% elongation (Ω) 1.2 2 1.7 440.6 1.05 8.9 240.5 Peel strength (gf / inch) 84 80 75 8 83 86 94 The peel strength (gf / inch) 1,060 1,020 890 350 1,240 1,330 1,420 Adhesion ○ ○ ○ × ○ × × Electromagnetic Shielding Rate (dB) 86 69 75 35 82 43 45

As can be seen in Table 1,

In Example 7, in which the conductive nanofiber web was not exposed, the surface resistance was remarkably reduced when the 15% elongation was compared to Example 6. [ In addition, it can be seen that in Example 6 in which the conductive nanofiber web was exposed in the preferred range of the present invention, the surface resistance was remarkably reduced when the 15% elongation was compared to Example 7. [

However, it can be seen that the surface resistance is significantly increased in the case of Example 4 which is excessively exposed, as compared with Example 3. Furthermore, in Example 4, the thickness of the first portion of the conductive adhesive layer was too small, confirming that the adhesion was also poor.

On the other hand, in Examples 6 and 7 in which the second portion thickness ratio of the conductive adhesive layer was less than 50%, the absolute thickness of the first portion of the conductive adhesive layer was thick compared to other embodiments, It can be confirmed that the adhesion property on the circuit board is poor. It can also be seen that Example 3, in which the second portion of the conductive adhesive layer was formed with an appropriate thickness even when the adhesive force was visually good, was superior in surface resistance and adhesive force at 15% elongation than in Example 2.

&Lt; Example 8 >

The same procedure as in Example 1 was carried out except that the nanofiber web after the primary calendering was changed to a nanofiber web prepared by performing a second calendering process under the same conditions without performing a pretreatment process, .

<Experimental Example 2>

The following properties of the EMI shielding films prepared according to Examples 1 and 8 were evaluated and are shown in Table 2 below.

1. Smoothness of conductive nanofiber web

The smoothness of the conductive nanofiber web prepared after the electroless plating process for the nanofiber web during the manufacturing process of the EMI shielding film was evaluated. The specimens of 15 cm and 15 cm in width and 15 cm in length were visually observed for the presence of convex portions. The convex portions were evaluated as "abnormal" when they existed, and "good" when they were not present.

The existence of the convex part is an appearance abnormality which occurs because the hydrogen gas generated in the nanofiber web during the electroless plating process can not be released outside the nanofiber web and is trapped inside.

2. Tensile Strength of Conductive Nanofiber Webs

The tensile strength of the conductive nanofiber web prepared after the electroless plating process for the nanofiber web was measured through a universal material tester (UTM, manufacturer LLOYD LF PLUS) apparatus during the manufacturing process of the EMI shielding film, and the results are shown.

3. Surface resistance at 30% elongation

The surface resistance of the fabricated EMI shielding film was measured on the lower surface of the electromagnetic shielding layer from which the release film was removed. The surface resistance was measured on a sample of 50 × 50 mm in size. The sample was stretched in one direction by about 30% The average value of the surface resistance was calculated and shown.

Example 1 Example 8 Conductive Nanofiber Web Smoothness Good More than Tensile strength (N / mm 2) 35 15 30% elongation at surface resistance (Ω) 12 150

As can be seen from Table 2, in Example 8 in which the pretreatment process was not performed on the nanofiber web, all of the properties were lowered in comparison with Example 1. [

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

10, 10 ': first release film 20, 20': electromagnetic wave shielding layer
21, 21 ': conductive nanofiber web 22: conductive adhesive layer
30, 30 ': protective layer 40, 40': second release film
100, 100 ': EMI shielding film 200: circuit board
210, 220: chip 1000: electromagnetic wave shielding type circuit board

Claims (18)

An electromagnetic wave shielding layer comprising a conductive nanofibrous web and a conductive adhesive layer, wherein the plurality of nanofibers including the conductive nanofibers form a three-dimensional network to form a plurality of pores; And
And a protective layer provided on the electromagnetic wave shielding layer. The method according to claim 1,
A part of the conductive nanofiber web is impregnated in the conductive adhesive layer on the basis of the thickness direction,
Wherein the entire conductive nanofiber web is impregnated in the conductive adhesive layer. The method according to claim 1,
Wherein the conductive nanofiber includes a supporting fiber portion, a surface coating layer coated on an outer surface of the supporting fiber portion, and a conductive portion covering a part or the whole of the outer surface of the surface coating layer,
And a conductive portion covering the support fiber portion and a part or all of the outer portion of the support fiber portion,
Wherein the conductive part is formed to include a region where the conductive nanofibers intersect when the conductive part covers only a part of the surface coating layer or the outside of the supporting fiber part. The method according to claim 1,
The conductive nanofiber web may include conductive nanofibers and non-conductive nanofibers. The conductive nanofibrous web may include the conductive nanofibers to a thickness of 1 to 80% of the total thickness of the conductive nanofiber web, &Lt; RTI ID = 0.0 &gt; EMI &lt; / RTI &gt; The method according to claim 1,
When a part of the conductive nanofiber web is impregnated into the conductive adhesive layer, the conductive nanofiber web part corresponding to 50 to 85% of the total thickness of the conductive nanofiber web is located in the conductive adhesive layer, The average thickness of the conductive adhesive layer portions not impregnated with the fibrous web is 3 to 12 占 퐉,
Wherein when the conductive nanofiber web is impregnated into the conductive adhesive layer, the conductive nanofibrous web is impregnated on one surface of the conductive adhesive layer or disposed so as not to be offset to any one surface of the conductive adhesive layer. film. The method according to claim 1,
Wherein a part of the conductive nanofibrous web is impregnated into the conductive adhesive layer on the basis of the thickness direction so that a conductive adhesive layer is positioned on a lower surface of the electromagnetic shielding layer and at least a part of the conductive nanofiber web is exposed And the exposed area of the conductive nanofiber web is 5 to 30% of the total area of the lower surface of the conductive nanofiber web. The method according to claim 6,
Wherein the lower surface of the electromagnetic wave shielding layer has a surface roughness (Ra) of 0.1 to 2 占 퐉. The method according to claim 1,
Wherein the conductive nanofibers have a diameter of 5 mu m or less and the conductive nanofiber web has an average pore size of 0.1 to 15 mu m, a thickness of 5 to 35 mu m, and a basis weight of 4 to 150 g / m &lt; 2 &gt;. The conductive adhesive layer according to claim 1,
A viscous component containing at least one organic compound selected from the group consisting of acrylic, silicone, urethane, polyester, polyolefin, vinyl chloride, vinyl acetate,
(Al), Cu (Cu), Ag, Zn, Pd, Ti, Zr, In, Ge, At least one metal filler selected from the group consisting of tin (Sn), gold (Au), iron (Fe) and alloys thereof, at least one conductive carbon selected from the group consisting of nickel-graphite, carbon black, carbon fiber and graphite Wherein the conductive filler comprises at least one filler selected from the group consisting of a filler and a filler. The method according to claim 1,
Wherein the conductive adhesive layer comprises an adhesive component and a conductive filler having a glass transition temperature of -20 캜 to 30 캜. The method according to claim 1,
Wherein the conductive adhesive layer comprises an adhesive component having an acid value of 30 to 300 mgKOH / g and a conductive filler. The method according to claim 1,
Wherein the conductive nanofiber web has a tensile strength of 20 N / mm 2 or more and a surface resistance of 500 m? Or less. 3. The method of claim 2,
The support fiber portion may be formed of a material selected from the group consisting of polyurethane, polyethylene, polypropylene, polystylene, polyvinylalcohol, polymethyl methacrylate, polylactic acid, But are not limited to, polyethylene oxide, polyvinyl acetate, polyacrylic acid, polycaprolactone, polyacrylonitrile, polyvinylpyrrolidone, polyvinylchloride ) Selected from the group consisting of polycarbonate, polycarbonate, polyetherimide, polyesthersulphone, polybenzimidazole, polyethylene terephthalate, polybutylene terephthalate and fluorine compounds. &Lt; / RTI &gt;
Wherein the conductive portion comprises at least one metal selected from the group consisting of aluminum, nickel, copper, silver, gold, chromium, platinum and titanium alloys. The method according to claim 1,
Wherein the conductive nanofibrous web has an elongation of 15 to 50% and a surface resistance of 2? Or less at 15% elongation in any one direction. Preparing a conductive nanofiber web;
Forming a protective layer on one side of the conductive nanofiber web and forming a conductive adhesive layer on the other side of the conductive nanofiber web; And
And applying a predetermined pressure so that a part of the conductive nanofiber web is impregnated into the conductive adhesive layer before compression. 16. The method of claim 15, wherein preparing the conductive nanofiber web
Fabricating a nanofiber web with a plurality of support fiber portions formed through electrospinning; And
And forming a conductive part on all or a part of the supporting fiber. A circuit board on which at least one chip is mounted; And
The EMI shielding film according to any one of claims 1 to 14, which is provided on the circuit board so as to cover at least the upper surface of the chip. An electronic device having an electromagnetic wave shielding type circuit board according to claim 17.

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