KR102227015B1 - EMI shielding-Heat radiation composite sheet and manufacturing method thereof - Google Patents

Abstract

The present invention relates to an electromagnetic shielding-radiation composite sheet and a method of manufacturing the same, and more particularly, excellent horizontal thermal conductivity and electromagnetic shielding properties, and at the same time, remarkably excellent interlayer adhesion, and visibility when applied to a display as no surface curvature occurs. The present invention relates to an electromagnetic shielding-radiating composite sheet exhibiting this very excellent effect and a method for manufacturing the same.

Description

EMI shielding-heat radiation composite sheet and manufacturing method thereof

The present invention relates to an electromagnetic shielding-radiation composite sheet and a method of manufacturing the same, and more particularly, excellent horizontal thermal conductivity and electromagnetic shielding properties, and at the same time, remarkably excellent interlayer adhesion, and visibility when applied to a display as no surface curvature occurs. The present invention relates to an electromagnetic shielding-radiating composite sheet exhibiting this very excellent effect and a method for manufacturing the same.

In recent years, as electric and electronic devices become more high-performance, light and thin, the demand for heat dissipation sheets that can effectively dissipate heat generated from heat sources such as semiconductor parts and light emitting parts embedded therein is steadily increasing. Functionalization is required.

In general, copper foil, copper foil/graphite laminate, graphite sheet, etc. are used as the heat dissipation sheet. Copper foil has both heat dissipation and electromagnetic wave shielding properties, but when the thickness increases, the flexibility is insufficient, and heat conduction in the horizontal direction is not suitable for graphite. It cannot be reached, and its high density has limitations in weight reduction. In addition, if the thickness is excessively thick, flexibility is insufficient, and thus it is limited to be applied as a heat dissipating sheet having a complex shape.

Meanwhile, an electromagnetic wave is a phenomenon in which energy moves in a sinusoidal shape while an electric field and a magnetic field are interlocked, and is usefully used in electronic devices such as wireless communication and radar. The electric field is generated by a voltage and is easily shielded by an obstacle such as a tree or a distance being increased, while the magnetic field is generated by an electric current and is inversely proportional to the distance, but is not easily shielded.

Recent electronic devices are sensitive to electromagnetic interference (EMI) generated by an internal interference source or an external interference source, and there is a concern that a malfunction of the electronic device may be caused by electromagnetic waves. In addition, users who use electronic devices may also be adversely affected by electromagnetic waves generated from the electronic devices.

Accordingly, in recent years, interest in electromagnetic wave shielding materials for protecting parts of electronic devices or human bodies from electromagnetic wave generating sources or electromagnetic waves radiated from the outside is increasing rapidly.

Meanwhile, commercial products composed of various materials are widely used as electromagnetic wave shielding sheets to block electromagnetic waves, but conventional electromagnetic wave shielding sheets have low thermal conductivity and thus cannot obtain sufficient heat dissipation effect. Therefore, various heat dissipation and electromagnetic wave shielding functions are applied. Composite sheets are being developed.

However, the conventional composite sheet can exhibit heat dissipation characteristics and electromagnetic wave shielding properties, but there is a problem in that the interlayer adhesion is not very good, and there is a problem that the visibility when applied to a display is markedly deteriorated as the surface of the composite sheet is bent.

Accordingly, it is urgent to develop a composite sheet that exhibits excellent horizontal thermal conductivity and electromagnetic wave shielding properties, remarkably excellent interlayer adhesion, and no surface curvature, and thus exhibits a very excellent effect of visibility when applied to a display.

Republic of Korea Patent Publication No. 2015-0077238 (published date: 2015-07-07)

The present invention was conceived to solve the above-described problems, and at the same time excellent horizontal thermal conductivity and electromagnetic wave shielding property, remarkably excellent interlayer adhesion, and excellent visibility when applied to a display as no surface curvature occurs. An object of the present invention is to provide an electromagnetic shielding-radiation composite sheet and a method of manufacturing the same.

The present invention in order to solve the above-described problem, the support member; Electromagnetic wave shielding layer; A graphite sheet interposed between the support member and the electromagnetic wave shielding layer and having a smaller cross-sectional area than that of the support member and the electromagnetic wave shielding layer, and thus having a predetermined step difference on at least one side thereof; A reinforcing member disposed at an outer periphery so as to surround at least one side surface of the graphite sheet to reinforce the step difference; And an adhesive layer provided on one or both sides of the graphite sheet.

According to an embodiment of the present invention, the reinforcing member may be disposed outside the graphite sheet so as to surround the entire side surface of the graphite sheet.

In addition, the adhesive layer may include a first region and a second region disposed to surround the first region, the graphite sheet may be provided on the first region, and the reinforcing member may include the second region. It may be provided on the area.

In addition, the reinforcing member may be disposed to surround at least one side of the graphite sheet with a width of 1 to 15 mm.

In addition, the average thickness of the reinforcing member may be 53 to 147% of the average thickness of the graphite sheet.

In addition, the graphite sheet may have an average thickness of 17 to 105 μm.

In addition, it may include a first adhesive layer and a second adhesive layer provided on the upper and lower surfaces of the graphite sheet, respectively.

In addition, the first adhesive layer and the second adhesive layer may each independently have an average thickness of 4 to 32 μm.

In addition, the adhesive layer is an adhesive layer comprising a main resin including at least one selected from the group consisting of acrylic resin, urethane resin, epoxy resin, silicone rubber, acrylic rubber, carboxyl nitrile elastomer, phenoxy and polyimide resin. It can be formed into a forming composition.

In addition, the adhesive layer-forming composition includes an epoxy-based curing agent, a diisocyanate-based curing agent, a secondary amine-based curing agent, a tertiary amine-based curing agent, a melamine-based curing agent, an isocyanic acid-based curing agent, and a phenolic curing agent based on 100 parts by weight of the main resin. It may further include 0.1 to 5 parts by weight of a curing agent having at least one selected from the group consisting of.

In addition, the support member may include one or more selected from the group consisting of polyimide, polyethylene terephthalate (PET), and polyethylene naphthalate (PEN), and the electromagnetic wave shielding layer may be copper foil or aluminum foil.

In addition, the support member may have an average thickness of 10 to 77 μm, and the electromagnetic wave shielding layer may have an average thickness of 4 to 52 μm.

In addition, the present invention comprises the steps of disposing a reinforcing member on an outer periphery of the graphite sheet to surround at least one side of the graphite sheet; And providing an adhesive layer on one or both sides of the graphite sheet, and providing a support member and an electromagnetic wave shielding layer on the upper and lower sides of the graphite sheet.

The electromagnetic shielding-radiation composite sheet and its manufacturing method according to the present invention have excellent horizontal thermal conductivity and electromagnetic shielding properties, and at the same time, have remarkably excellent interlayer adhesion and excellent visibility when applied to a display. I can.

1 is an exploded perspective view of an electromagnetic shielding-heat radiating composite sheet according to an embodiment of the present invention,
2 is a cross-sectional view of an electromagnetic wave shielding-heat radiating composite sheet according to an embodiment of the present invention,
3 is a cross-sectional view of an electromagnetic wave shielding-radiation composite sheet according to another embodiment of the present invention,
4 is a cross-sectional view of an electromagnetic wave shielding-radiation composite sheet according to another embodiment of the present invention,
5 is a schematic diagram showing a through hole formed in a graphite sheet provided in an electromagnetic shielding-radiation composite sheet according to an embodiment of the present invention, and,
6 is a flowchart illustrating a method of manufacturing an electromagnetic shielding-heat radiating composite sheet according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art may easily implement the present invention. The present invention may be implemented in various different forms and is not limited to the embodiments described herein. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and the same reference numerals are added to the same or similar components throughout the specification.

As shown in Figure 1, electromagnetic wave shielding-radiation composite sheet 1000 according to an embodiment of the present invention, a support member 300; Electromagnetic wave shielding layer 400; It is interposed between the support member 300 and the electromagnetic wave shielding layer 400, and has a small cross-sectional area compared to the support member 300 and the electromagnetic wave shielding layer 400, thus having a predetermined step on at least one side. Graphite sheet 100; A reinforcing member 110 disposed at an outer periphery so as to surround at least one side surface of the graphite sheet 100 to reinforce the step difference; And an adhesive layer 200 provided on one or both surfaces of the graphite sheet 100.

First, the graphite sheet 100 will be described.

As described above, as the graphite sheet 100 has a smaller cross-sectional area than the support member 300 and the electromagnetic vehicle shielding layer 400 to be described later, the graphite sheet 100 is provided such that a predetermined step is generated on at least one side thereof.

The graphite sheet may be used without limitation as long as it is a general graphite sheet commonly used in the art, and a graphite sheet including at least one of pyrolytic graphite and graphitized polyimide may be used.

The pyrolytic graphite refers to high-purity graphite having high thermal conductivity and electrical conductivity, is used at a high temperature, is manufactured by a vapor deposition method, and may have a very well-developed microstructure.

The graphitized polyimide may be prepared through the following graphitization process. First, as a preparatory step of the graphitization process, the polyimide may be added to the sintering furnace by laminating it on a natural graphite sheet. Such a preparatory step may be performed in order to prevent fusion between the films, although the polyimide may have a film form. Next, as a first step of the graphitization process, a carbonization treatment step of the polyimide may be performed at a temperature of 600° C. to 1,800° C. for 2 to 7 hours. Through such a carbonization treatment step, nitrogen, hydrogen, and components in addition to carbon in the polyimide can be removed. Finally, as a second step of the graphitization process, a heat treatment step may be performed at a temperature of 2,000°C to 3,200°C. Different alignments of the carbon atoms can be caused through such a heat treatment step. Specifically, after the first step, pores may exist between the stacks of carbon in the polyimide, and heat dissipation performance by increasing the density and removing pores by passing through a rolling roll at a temperature of 2,000°C to 3,200°C. This maximized graphitized polyimide can be produced.

Meanwhile, the graphite sheet 100 may have an average thickness of 17 to 105 μm, preferably 17 to 100 μm, more preferably 17 to 60 μm, and even more preferably 25 to 40 μm. have. When the average thickness of the graphite sheet 100 is less than 17 μm, the desired level of heat dissipation characteristics cannot be expressed, and when the average thickness exceeds 105 μm, the adhesion between the graphite layers may be relatively lowered.

Next, the reinforcing member 110 will be described.

As described above, the reinforcing member 110 is disposed on the outer periphery so as to surround at least one side of the graphite sheet 100 in order to reinforce the step difference, and more preferably, the graphite sheet ( 100) may be arranged to surround the entire side.

The reinforcing member 110 has excellent visibility when applied to a display as the electromagnetic wave shielding-radiation composite sheet 1000 according to the present invention does not generate surface curvature, and has excellent horizontal thermal conductivity, electromagnetic wave shielding property, and interlayer adhesion. Any material that allows it to be expressed can be used without limitation.

For example, as shown in FIG. 2, the reinforcing member 110 may be a film-like substrate. At this time, the film-like substrate may preferably include one or more selected from the group consisting of polyimide, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polyolefin (PO), and more preferably polyethylene. It may contain terephthalate (PET).

In addition, as another example, the reinforcing member 110 may be one selected from the group consisting of a double-sided tape-shaped adhesive member, a thermally conductive member, and a nanofiber web-shaped member.

When the reinforcing member 110 is a double-sided tape-shaped adhesive member for reinforcing the surface of the electromagnetic wave shielding-heating composite sheet 1000 to prevent bending and improving interlayer adhesion, it is shown in FIG. 3. As described above, the reinforcing member 110 may include a substrate 110a and adhesive layers 110b and 110c formed on one or both sides of the substrate.

The substrate 110a may be used without limitation, as long as it is a substrate commonly used in the art, and preferably from the group consisting of polyimide, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polyolefin (PO). It may include at least one selected, and more preferably may include polyethylene terephthalate (PET).

Meanwhile, the thickness of the substrate 110a may be 20 to 84% of the total thickness of the reinforcing member 110, and preferably 20 to 83.5% of the total thickness of the reinforcing member 110. If the thickness of the substrate 110a relative to the total thickness of the reinforcing member 110 is less than 20%, the function of reinforcing the surface to not be curved is insignificant, resulting in surface curvature, and visibility decreases when applied to a display. If the thickness exceeds 84%, interlayer adhesion may decrease.

In addition, the substrate 110a may have an average thickness of 3 to 77 μm, preferably 4 to 75 μm, and more preferably 12 to 50 μm to satisfy the above ratio. If the average thickness of the substrate 110a is less than 3 μm, the function of reinforcing the surface to not be curved is insignificant, resulting in surface curvature, and visibility may decrease when applied to a display, and the average thickness is 77 μm. If it exceeds, the interlayer adhesion may be lowered.

The adhesive layer (110b, 110c) is at least one selected from the group consisting of acrylic resin, urethane resin, epoxy resin, silicone rubber, acrylic rubber, carboxyl nitrile elastomer, phenoxy and polyimide resin, preferably May be formed of an adhesive layer forming composition including a main resin having an acrylic resin. And the adhesive layer-forming composition is composed of an epoxy-based curing agent, a diisocyanate-based curing agent, a secondary amine-based curing agent, a tertiary amine-based curing agent, a melamine-based curing agent, an isocyanic acid-based curing agent, and a phenolic curing agent based on 100 parts by weight of the main resin. It may further include 0.1 to 5 parts by weight, preferably 0.1 to 2 parts by weight, of a curing agent having at least one selected from the group, preferably an epoxy-based curing agent. If the curing agent is less than 0.1 parts by weight based on 100 parts by weight of the main resin, the desired level of interlayer adhesion cannot be expressed as the adhesive layer may be uncured, and if it exceeds 5 parts by weight, the adhesive strength due to overcuring may decrease. Therefore, the desired level of interlayer adhesion cannot be expressed.

On the other hand, the main resin and the curing agent may be the same as the main resin and the curing agent provided in the adhesive layer forming composition forming the adhesive layer 200 to be described later, in this case, the compatibility between the adhesive layer and the adhesive layer to be described later and due to It may be more advantageous in terms of improving interlayer adhesion.

In addition, when the reinforcing member is a double-sided tape-shaped adhesive member, the reinforcing member 110 may include a substrate 110a and adhesive layers 110b and 110c formed on one or both sides of the substrate, as described above, and , Preferably, it may include a first adhesive layer (110b) and a second adhesive layer (110c) provided respectively on the upper and lower surfaces of the substrate (110a). Accordingly, it may be more advantageous in terms of improving the interlayer adhesion as the adhesion to the adhesive layer to be described later may be more excellent.

In this case, the first adhesive layer 110b and the second adhesive layer 110c may each independently have an average thickness of 4 to 32 μm so as to satisfy the ratio of the thickness of the base material 110a to the total thickness of the reinforcing member 110 And, preferably, it may be 5 ~ 30㎛, more preferably it may be 5 ~ 25㎛. If the average thickness of the first adhesive layer 110b and the second adhesive layer 110c is less than 4 μm, the interlayer adhesive strength may decrease. If the average thickness exceeds 32 μm, surface curvature occurs, and visibility when applied to a display This can be degraded.

In addition, when the reinforcing member 110 is a thermally conductive member for performing a function of improving heat dissipation characteristics by reinforcing the reinforcing member 110 so that the surface does not bend, and improving vertical and/or horizontal thermal conductivity, as shown in FIG. As described above, the reinforcing member 110 may include a thermally conductive member alone, and as shown in FIG. 3, the reinforcing member 110 is formed on one or both sides of the substrate 110a, which is a thermally conductive member. It may include adhesive layers (110b, 110c).

The thermally conductive member may be used without limitation as long as it is a thermally conductive member commonly used in the art, and preferably including one selected from the group consisting of a graphite member and a metal member is reinforced so that the surface does not bend. And, it may be advantageous in terms of vertical and/or horizontal thermal conductivity improvement.

In addition, the metal member may be used without limitation as long as it is a metal member commonly used in the art. Preferably, copper (Cu), aluminum (Al), silver (Ag), nickel (Ni), gold (Au) And it may include one or more selected from the group consisting of an alloy containing two or more of these, more preferably may include copper (Cu).

In addition, the thermally conductive member may have a predetermined surface roughness by forming irregularities on the surface in order to improve compatibility and heterogeneous bonding with the adhesive layer 200 or the adhesive layers 110b and 110c to be described later. Accordingly, as the unevenness formed on the surface serves as an anchor, the interlayer adhesion may exhibit a more excellent effect.

On the other hand, when the reinforcing member 110 includes a substrate 110a as a thermally conductive member and adhesive layers 110b and 110c formed on one or both sides of the substrate, the thickness of the thermally conductive member 110a is the reinforcement. The total thickness of the member 110 may be 70% or more, and preferably 80% or more. If the thickness of the substrate 110a, which is a thermally conductive member, is less than 70% of the total thickness of the reinforcing member 110, the function of reinforcing the surface to avoid bending is insignificant, resulting in surface curvature and applied to the display. Visibility may be deteriorated, and heat dissipation characteristics may not be improved to a desired level.

In addition, when the reinforcing member 110 includes a thermally conductive member, as described above, it may include an adhesive layer formed on one or both surfaces of the substrate 110a, which is a thermally conductive member, and preferably, the thermally conductive member It may include a first adhesive layer (110b) and a second adhesive layer (110c) provided on the upper and lower surfaces of the substrate (110a), respectively. Accordingly, it may be more advantageous in terms of improving the interlayer adhesion as the adhesion to the adhesive layer to be described later may be more excellent.

In this case, the first adhesive layer 110b and the second adhesive layer 110c may each independently have an average thickness of less than 32 μm, preferably less than 30 μm, and more preferably less than 25 μm. If the average thickness of the first adhesive layer 110b and the second adhesive layer 110c exceeds 32 μm, surface curvature may occur, and visibility may decrease when applied to a display.

On the other hand, when the reinforcing member includes a thermally conductive member, a description other than the above description of the adhesive layer is the same as the description of the adhesive layer provided in the above-described double-sided tape-shaped adhesive member, and thus will be omitted.

In addition, as shown in Fig. 4, the reinforcing member 110 reinforces the surface so that it does not bend, improves the interlayer adhesion of the electromagnetic wave shield-heating composite sheet 1000, and has vertical and/or horizontal thermal conductivity. In the case of a nanofiber web-shaped substrate for performing a function of improving heat dissipation by improving the heat dissipation property, the reinforcing member 110 may include a porous nanofiber web formed of a plurality of nanofibers 110d.

The nanofiber (110d) may be formed by using without limitation any material that can be used to form nanofibers conventionally in the art, preferably polyimide, polyurethane, polyvinyl alcohol, polymethyl methacrylate, It may be formed by including one or more selected from the group consisting of polyvinyl acetate, polyacrylic acid, polyvinylpyrrolidone and polyethylene terephthalate.

In this case, the nanofibers 110d may have an average fiber diameter of 150 to 800 nm, and preferably 200 to 600 nm. If the average fiber diameter of the nanofibers is less than 150 nm, the function of reinforcing the surface to not be curved is insignificant, resulting in surface curvature, and visibility may decrease when applied to a display, and the average fiber diameter is 800 nm. If it exceeds, the desired level of interlayer adhesion may not be expressed.

In addition, the nanofiber web may include a heat conductive layer 110e coated on at least a portion of the surface of the nanofiber 110d, preferably coated on the entire surface of the nanofiber 110d in order to improve thermal conductivity. have.

At this time, the heat conductive layer 110e may be used without limitation as long as it is a metal capable of expressing excellent thermal conductivity. Preferably, copper (Cu), aluminum (Al), silver (Ag), nickel (Ni), gold ( Au) and may include one or more selected from the group consisting of an alloy containing two or more of them.

In addition, the heat conductive layer 110e may be coated in a single layer shape on at least a part of the surface of the nanofibers 110d, may be coated in a two-layer shape, or may be coated in a three-layer shape. For example, when the heat conductive layer 110e is coated in a three-layer shape, the heat conductive layer 110e is a first heat conductive layer including nickel (Ni) sequentially coated on at least a portion of the surface of the nanofibers 110d. , A second heat conductive layer containing copper (Cu) and a third heat conductive layer containing nickel (Ni) in a thickness ratio of 1: 0.5 to 1.5: 0.5 to 1.5, preferably 1: 0.7 to 1.3: 0.7 to 1.3 It may be included as a thickness ratio of, but is not limited thereto.

Meanwhile, the nanofiber web may have a porosity of 30 to 70%, preferably 40 to 60%. If the porosity of the nanofiber web is less than 30%, the desired level of interlayer adhesion may not be expressed, and if the porosity exceeds 70%, the function of reinforcing the surface so as not to bend is insignificant. This occurs, and when applied to a display, visibility may decrease, and thermal conductivity may decrease.

In addition, in the nanofiber web, at least a portion of the pores may be blocked with the adhesive component 110f in order to improve peel strength.

On the other hand, the description of the adhesive component when the reinforcing member includes a nanofiber web-shaped member is the same as the description of the component forming the adhesive layer provided on the double-sided tape-shaped adhesive member. It should be omitted.

In addition, the main resin and the curing agent forming the adhesive component may be the same as the main resin and the curing agent provided in the adhesive layer forming composition forming the adhesive layer 200 to be described later, in this case, the adhesive component and the adhesive layer to be described later It may be more advantageous in terms of inter-layer compatibility and thus improved interlayer adhesion.

Meanwhile, the adhesive layer 200 to be described later may include a first region and a second region disposed to surround the first region, and as shown in FIG. 1, the graphite sheet 100 The reinforcing member 110 may be provided on the second region.

In addition, the reinforcing member 110 may be disposed to surround at least one side of the graphite sheet 100 with a width of 1 to 15 mm, and preferably may be disposed to surround the graphite sheet 100 with a width of 2 to 13 mm. . If the width of the reinforcing member is less than 1 mm, the effect of preventing delamination of the graphite sheet may be lowered, and visibility may decrease when applied to a display due to the occurrence of surface curvature. If it exceeds 15 mm, the heat dissipation performance is relatively This may decrease, and visibility may decrease.

In addition, the average thickness of the reinforcing member 110 may be 53 to 147%, preferably 76 to 124% of the average thickness of the graphite sheet 100. If the average thickness of the reinforcing member 110 is less than 53% of the average thickness of the graphite sheet 100, visibility may decrease when applied to a display due to a step difference with the graphite sheet, and interlayer adhesion may decrease. If it exceeds 147%, visibility may be reduced due to protrusion of the reinforcing member, and interlayer adhesion may be reduced due to a step difference between the reinforcing member and the graphite sheet.

Next, the adhesive layer 200 will be described.

The adhesive layer 200 is formed on one or both surfaces of the graphite sheet 100 to improve interlayer adhesion.

The adhesive layer 200 comprises at least one selected from the group consisting of acrylic resin, urethane resin, epoxy resin, silicone rubber, acrylic rubber, carboxyl nitrile elastomer, phenoxy and polyimide resin, preferably acrylic resin. It may be formed of an adhesive layer-forming composition including a main resin. And the adhesive layer-forming composition, based on 100 parts by weight of the main resin, an epoxy-based curing agent, a diisocyanate-based curing agent, a secondary amine-based curing agent, a tertiary amine-based curing agent, a melamine-based curing agent, an isocyanic acid-based curing agent, and a phenolic curing agent. A curing agent having at least one selected from the group consisting of, preferably, an epoxy-based curing agent may be further included in an amount of 0.1 to 5 parts by weight, preferably 0.1 to 2.0 parts by weight. If the curing agent is less than 0.1 parts by weight based on 100 parts by weight of the main resin, the desired level of interlayer adhesion cannot be expressed as the adhesive layer may be uncured, and if it exceeds 5 parts by weight, the adhesive strength due to overcuring decreases. Because of this, the desired level of interlayer adhesion cannot be expressed.

In this case, the main resin and the curing agent may be the same as the main resin and curing agent provided in the composition forming the adhesive layer (110b, 110c) and the adhesive component (110f), in this case, the adhesive layer or the adhesive component and the adhesive It may be more advantageous in terms of interlayer compatibility and thus improving interlayer adhesion.

Meanwhile, as described above, the adhesive layer 200 may include a first adhesive layer 210 and a second adhesive layer 220 provided respectively on the upper and lower surfaces of the graphite sheet 100. Accordingly, as the adhesion to the reinforcing member 110 described above may be more excellent, it may be more advantageous in terms of improving interlayer adhesion.

At this time, the first adhesive layer 210 and the second adhesive layer 220 may each independently have an average thickness of 4 to 32 μm, preferably 5 to 30 μm, more preferably 5 to It may be 24 μm. If the average thickness of the first adhesive layer 210 and the second adhesive layer 220 is less than 4 μm, the interlayer adhesive strength may decrease, and if the average thickness exceeds 32 μm, it is not preferable in terms of thinning, and a limited thickness In the case of forming the electromagnetic wave shielding-radiation composite sheet 1000 as the graphite sheet 100 is relatively thin, the heat dissipation characteristics may be degraded, which is not preferable.

Next, the support member 300 will be described.

The support member 300 functions to support the electromagnetic shielding-heating composite sheet 1000, and any material that can be used to perform the role of a support member generally in the art may be used without limitation, and preferably May include one or more selected from the group consisting of polyimide, polyethylene terephthalate (PET), and polyethylene naphthalate (PEN), and more preferably polyimide.

Meanwhile, the support member 300 may have an average thickness of 10 to 77 μm, preferably 12 to 75 μm, and more preferably an average thickness of 25 to 50 μm. If the average thickness of the support member 300 is less than 10 μm, the durability of the electromagnetic shielding-heating composite sheet 1000 may be deteriorated, and if the average thickness exceeds 77 μm, it is not preferable because it is very disadvantageous in terms of thinning. .

Next, the electromagnetic wave shielding layer 400 will be described.

The electromagnetic wave shielding layer 400 is a material having heat dissipation and electromagnetic wave shielding functions, and may be used without limitation as long as it is a general metal foil commonly used in the art, and preferably copper foil or aluminum foil may be used.

In addition, the electromagnetic wave shielding layer 400 may have an average thickness of 4 to 52 μm, preferably an average thickness of 5 to 50 μm, more preferably an average thickness of 12 to 40 μm. If the average thickness of the electromagnetic wave shielding layer 400 is less than 4 μm, the electromagnetic wave shielding power and heat dissipation characteristics may be deteriorated, and tearing may occur, and if it exceeds 52 μm, thinning becomes difficult and flexibility may be reduced. have.

Meanwhile, according to another embodiment of the present invention, the graphite sheet 100 may be implemented as a graphite sheet in which a plurality of through holes are formed as shown in FIG. 5, and the interlayer adhesion can be further improved through such through holes. I can.

In addition, the through hole may be a through hole 1 formed at regular intervals as shown in FIG. 5, may be a through hole 2 formed at different intervals and alternately arranged, and randomly formed through holes ( 3), but is not limited thereto.

In addition, although the shape of the through hole is shown in a circular shape in FIG. 5, this is only for helping understanding of the present invention, and there is no limitation on the cross-sectional shape of the through hole that may be provided in the graphite sheet of the present invention. As an example, the cross-sectional shape of the through hole may be circular, polygonal, cross-shaped, C-shaped, four-leafed, six-leafed, eight-leafed, etc., and these shapes may be used alone, or the cross-sectional shapes may be used for purposes and uses, etc. As it may be mixed and used according to the present invention, it is not particularly limited in the present invention.

In addition, the area of the through-holes of the graphite sheet 100 may be 2% to 30%, preferably 3.5% to 15%, more preferably 3.5% to 10% of the total area of the upper or lower surface of the graphite layer. In this case, if the through-hole area is less than 2%, interlayer adhesion may be relatively reduced, and if it exceeds 30%, there may be a problem in that horizontal thermal conductivity is lowered.

According to another embodiment of the present invention, a second reinforcing member may be further included in the through hole.

Since the second reinforcing member may have the same shape and material as the above-described reinforcing member 110, a description of the shape and material will be omitted.

Meanwhile, the electromagnetic wave shielding-heating composite sheet 1000 according to the present invention may further include an adhesive member (not shown) formed on one surface of the support member 300.

The adhesive member performs a function of adhering to the display when the electromagnetic shielding-heating composite sheet is applied to the display, and according to the present invention, any material capable of forming an adhesive member can be used without limitation in the art. In no particular limitation is given to this. For example, the adhesive member may be a PSA adhesive member.

In addition, the electromagnetic wave shielding-heating composite sheet 1000 according to the present invention may further include a protective layer (not shown) formed on one surface of the electromagnetic wave shielding layer 400.

The protective layer protects the electromagnetic wave shielding-radiation composite sheet 1000, and performs a function of protecting the display when the electromagnetic wave shielding-heating composite sheet 1000 is applied to the display, and is commonly used as a protective layer in the art. As long as the material can be used without limitation, in the present invention, this is not particularly limited.

Meanwhile, the electromagnetic wave shielding-heating composite sheet of the present invention may be manufactured through a manufacturing method described below, but is not limited thereto.

Electromagnetic wave shielding-radiation composite sheet according to the present invention, as shown in Figure 6, the steps of disposing a reinforcing member to surround at least one side of the graphite sheet (S1); And providing an adhesive layer on one or both sides of the graphite sheet, and providing a support member and an electromagnetic wave shielding layer on top and bottom (S2).

On the other hand, before the step of disposing a reinforcing member to surround at least one side of the graphite sheet, forming a plurality of through holes in the graphite sheet; And providing a second reinforcing member in the through hole of the graphite sheet.

The electromagnetic shielding-radiation composite sheet and its manufacturing method according to the present invention have excellent horizontal thermal conductivity and electromagnetic shielding properties, and at the same time, have remarkably excellent interlayer adhesion and excellent visibility when applied to a display. I can.

The present invention will be described in more detail through the following examples, but the following examples do not limit the scope of the present invention, which should be construed to aid understanding of the present invention.

<Example 1>

(1) Manufacture of electromagnetic shielding-heat radiating composite sheet

First, through a punching process, a plurality of through holes are formed in a graphite sheet having a thickness of 25 μm, and in the inside of the plurality of through holes, a second polyethylene terephthalate (PET) substrate having a thickness of 25 μm having the same cross-sectional shape as the through hole. After the reinforcing member is provided, a punching process is performed so that a reinforcing member having a width of 5 mm, which is a polyethylene terephthalate (PET) base material having a thickness of 25 μm, is disposed so as to surround the entire side surface of the graphite sheet, and the graphite sheet on which the reinforcing member is disposed. A first adhesive layer and a second adhesive having a thickness of 5 μm each with an adhesive layer forming composition containing 1 part by weight of an acrylic rubber as a main resin and an epoxy-based curing agent as a curing agent per 100 parts by weight of the main resin on the upper and lower surfaces of the A laminate was prepared by forming a layer.

After preparing a laminate by providing a polyimide film having a thickness of 25 μm as a support member on the top of the prepared laminate and a copper foil having a thickness of 18 μm as an electromagnetic wave shielding layer at the bottom, An electromagnetic wave shielding-heat radiating composite sheet as shown in FIGS. 1 and 2 was manufactured using the laminated body.

<Examples 2 to 9>

It was prepared in the same manner as in Example 1, but by changing the width of the reinforcing member and the average thickness of the reinforcing member compared to the average thickness of the graphite sheet, an electromagnetic wave shielding-heating composite sheet as shown in Tables 1 to 3 was prepared.

<Example 10>

Prepared in the same manner as in Example 1, but 1 part by weight of an epoxy-based curing agent as a curing agent per 100 parts by weight of a 12 µm-thick polyethylene terephthalate (PET) base as a reinforcing member, acrylic rubber as a base resin, and 100 parts by weight of the base resin. An electromagnetic wave shielding-heat radiating composite sheet as shown in FIG. 3 by providing a reinforcing member having a first adhesive layer and a second adhesive layer having a thickness of 7 μm and 6 μm, respectively, formed on the upper and lower surfaces of the substrate with an adhesive layer forming composition comprising Was prepared.

<Example 11>

Manufactured in the same manner as in Example 1, but provided with a reinforcing member including a thermally conductive member made of copper (Cu) having a thickness of 25 µm as a reinforcing member and having irregularities on the surface, electromagnetic wave shielding-heat radiation as shown in FIGS. 1 and 2 A composite sheet was prepared.

<Example 12>

It was manufactured in the same manner as in Example 1, but by providing a reinforcing member manufactured according to the following preparation example, an electromagnetic wave shielding-heat radiating composite sheet as shown in FIG. 4 was manufactured.

<Preparation example>

A spinning solution containing 15 g of polyurethane and 85 g of acetone was added to a solution tank of an electrospinning apparatus, and discharged at a rate of 15 μl/min/hole. At this time, the temperature of the spinning section is maintained at 30℃ and the humidity is 50%, the distance between the collector and the spinning nozzle tip is 20cm, and a high voltage generator is used to apply a voltage of 40kV or more to the spinning nozzle pack. A fiber web formed of nanofibers having an average fiber diameter of 400 nm was prepared by applying an air pressure of 0.03 MPa per nozzle of the spinning pack, and then nickel, copper and nickel were sequentially electroless plated to cover at least a part of the surface of the nanofibers. A thermally conductive layer was formed to prepare a nanofiber web having a porosity of 50%. Thereafter, the nanofiber web is impregnated into an adhesive composition containing 1 part by weight of an acrylic resin as a first main resin and 1 part by weight of an epoxy-based curing agent as a first curing agent based on 100 parts by weight of the first main resin, so that at least part of the pores of the nanofiber web A reinforcing member having a thickness of 25 µm was prepared by punching the impregnated nanofiber web and blocked with an adhesive component.

<Comparative Example 1>

It was manufactured in the same manner as in Example 1, but without a reinforcing member, an electromagnetic wave shielding-heating composite sheet was manufactured.

<Experimental Example>

The following physical properties were evaluated for the electromagnetic wave shielding-radiation composite sheets prepared in Examples and Comparative Examples, and are shown in Tables 1 to 3.

1. Measurement of peel strength (gf/㎠)

The electromagnetic shielding-heating composite sheet prepared according to Examples and Comparative Examples was prepared in accordance with JIS C 6741 standard, and the peel strength of the entire reinforcing member disposed on the outer side was performed by a 180° peel test. And measured.

2. Measurement of thermal diffusivity

The electromagnetic wave shielding-radiation composite sheet prepared according to Examples and Comparative Examples was cut into a size of 100 mm×10 mm horizontally × vertically, and a double-sided tape was attached to one side of the electromagnetic wave shielding layer.

Next, the prepared sample is attached to the heating block and the temperature of the heating block is raised to 80°C (evaluation proceeds by raising the temperature to 80°C, which is the level of the heating temperature of the AP chip in the smart phone).

Next, after sealing the heating block in the box, stabilization is performed for 10 minutes, and then the temperature is measured using an IR camera to determine the hot spot and cold spot of the composite sheet. It was measured, and the temperature difference was calculated to measure the thermal diffusivity of the composite sheet. At this time, the smaller the difference ㅿT value between the two temperatures, the better the heat dissipation performance.

3. Electromagnetic shielding performance evaluation

The electromagnetic wave shielding-heating composite sheet prepared according to Examples and Comparative Examples was evaluated for electromagnetic wave shielding performance in the 1 GHz band using a vector network analyzer (Anritsu Corporation).

4. Visibility evaluation

The electromagnetic wave shielding-heat-radiating composite sheet prepared according to Examples and Comparative Examples was visually inspected using a roll inspection machine. Specifically, the manufactured electromagnetic shielding-heating composite sheet was hung on a roll inspection machine, and a total visual inspection was performed on the appearance of the electromagnetic shielding layer underneath corresponding to the area on the reinforcing member disposed on the outer side. The result was confirmed by a thickness measurement method using a micrometer.

At this time, the appearance of the lower electromagnetic wave shielding layer was divided into a graphite sheet thickness compared to the thickness of the graphite sheet, when a thickness difference of ±4㎛ occurs-○, when a thickness difference occurs ±8㎛-△, when a thickness difference exceeds ±8㎛ occurs-×.

division Example
One Example
2 Example
3 Example
4 Example
5 Bo
River
part
ashes Width of reinforcing member (mm) 5 0.3 2 13 17 Average thickness compared to the average thickness of graphite sheet (%) 100 100 100 100 100 Material and shape PET film PET film PET film PET film PET film Included or not ○ ○ ○ ○ ○ Peel strength (gf/㎠) 401 72 287 884 1,103 Thermal diffusion (heat dissipation) (ㅿT, ℃) 21.70 21.68 21.69 21.73 22.98 Electromagnetic shielding performance (dB) -69.6 -69.6 -69.6 -69.6 -69.6 Visibility evaluation ○ × ○ ○ △

division Example
6 Example
7 Example
8 Example
9 Example
10 Bo
River
part
ashes Width of reinforcing member (mm) 5 5 5 5 5 Average thickness compared to the average thickness of graphite sheet (%) 30 76 124 167 100 Material and shape PET film PET film PET film PET film Double-sided tape Included or not ○ ○ ○ ○ ○ Peel strength (gf/㎠) 298 378 381 301 551 Thermal diffusion (heat dissipation) (ㅿT, ℃) 22.07 21.71 21.71 21.70 21.80 Electromagnetic shielding performance (dB) -69.6 -69.6 -69.6 -69.6 -69.6 Visibility evaluation × ○ ○ × ○

division Example
11 Example
12 Comparative example
One Bo
River
part
ashes Width of reinforcing member (mm) 5 5 - Average thickness compared to the average thickness of graphite sheet (%) 100 100 - Material and shape Thermally conductive member Nano Fiber Web - Included or not ○ ○ × Peel strength (gf/㎠) 376 420 - Thermal diffusion (heat dissipation) (ㅿT, ℃) 20.74 21.25 21.76 Electromagnetic shielding performance (dB) -69.6 -69.6 -69.6 Visibility evaluation ○ ○ ×

As can be seen from Tables 1 to 3, Examples 1 and 3 satisfying all of the width of the reinforcing member according to the present invention, the average thickness of the reinforcing member compared to the average thickness of the graphite sheet, the type of the reinforcing member, and whether or not the reinforcing member is included. , 4, 7, 8, and 10 to 12 have excellent peeling strength compared to Examples 2, 5, 6, 9 and Comparative Example 1 in which any one of them is omitted, heat dissipation performance and electromagnetic wave shielding power are excellent, and at the same time, visibility is excellent. All of the excellent effects could be achieved at the same time.

In particular, Example 10 using a double-sided tape-shaped adhesive member as a reinforcing member for the purpose of further improving the peel strength, it can be confirmed that the peel strength is very excellent, but other physical properties are also excellent, and to further improve the heat dissipation performance. Example 11, in which a thermally conductive member was used as a reinforcing member for the purpose, was very excellent in heat dissipation performance, but other physical properties were also excellent, and for the purpose of further improving the peel strength and heat dissipation performance, a nanofiber web shape was used as a reinforcing member. It can be seen that Example 12 using the member of is excellent in peel strength and heat dissipation performance, and other physical properties are also excellent.

Although an embodiment of the present invention has been described above, the spirit of the present invention is not limited to the embodiment presented in the present specification, and those skilled in the art who understand the spirit of the present invention can add components within the scope of the same idea. It will be possible to easily propose other embodiments by changing, deleting, adding, etc., but this will also be said to fall within the scope of the present invention.

1, 2, 3: through hole
100: graphite sheet
110: reinforcing member
110a: substrate
110b: first adhesive layer
110c: second adhesive layer
110d: nanofiber
110e: heat conductive layer
110f: adhesive component
200: adhesive layer
210: first adhesive layer
220: second adhesive layer
300: support member
400: electromagnetic wave shielding layer
1000: electromagnetic wave shielding-heat radiating composite sheet

Claims (13)

Support member;
Electromagnetic wave shielding layer;
A graphite sheet interposed between the support member and the electromagnetic wave shielding layer and having a smaller cross-sectional area than that of the support member and the electromagnetic wave shielding layer, and thus having a predetermined step difference on at least one side thereof;
A reinforcing member disposed at an outer periphery so as to surround at least one side surface of the graphite sheet to reinforce the step difference; And
Including; an adhesive layer provided on one or both sides of the graphite sheet,
The reinforcing member is disposed to surround at least one side of the graphite sheet with a width of 1 to 15 mm,
The average thickness of the reinforcing member is 53 to 147% of the average thickness of the graphite sheet electromagnetic shielding-heat radiating composite sheet. The method of claim 1,
The reinforcing member is an electromagnetic wave shielding-heat radiating composite sheet disposed on an outer periphery so as to surround the entire side surface of the graphite sheet. The method of claim 1,
The adhesive layer includes a first region and a second region disposed to surround the first region,
The graphite sheet is provided on the first region,
The reinforcing member is an electromagnetic wave shielding-radiation composite sheet provided on the second area. delete delete The method of claim 1,
The graphite sheet has an average thickness of 17 ~ 105㎛ electromagnetic wave shielding-radiation composite sheet. The method of claim 1,
Electromagnetic wave shielding-radiation composite sheet comprising a first adhesive layer and a second adhesive layer provided on the upper and lower surfaces of the graphite sheet, respectively. The method of claim 7,
The first adhesive layer and the second adhesive layer are each independently an electromagnetic wave shielding-radiation composite sheet having an average thickness of 4 to 32 μm. The method of claim 1,
The adhesive layer includes a main resin comprising at least one selected from the group consisting of acrylic resin, urethane resin, epoxy resin, silicone rubber, acrylic rubber, carboxyl nitrile elastomer, phenoxy and polyimide resin. Electromagnetic wave shielding-radiation composite sheet formed of an adhesive layer-forming composition. The method of claim 9, wherein the adhesive layer-forming composition,
At least one selected from the group consisting of an epoxy-based curing agent, a diisocyanate-based curing agent, a secondary amine-based curing agent, a tertiary amine-based curing agent, a melamine-based curing agent, an isocyanic acid-based curing agent, and a phenolic curing agent based on 100 parts by weight of the main resin. Electromagnetic wave shielding-radiation composite sheet further comprising 0.1 to 5 parts by weight of a curing agent to be provided. The method of claim 1,
The support member includes at least one selected from the group consisting of polyimide, polyethylene terephthalate (PET), and polyethylene naphthalate (PEN),
The electromagnetic shielding layer is an electromagnetic shielding-radiation composite sheet of copper foil or aluminum foil. The method of claim 1,
The support member has an average thickness of 10 ~ 77㎛,
The electromagnetic shielding layer has an average thickness of 4 ~ 52㎛ electromagnetic shielding-heat radiating composite sheet. Disposing a reinforcing member on an outer periphery of the graphite sheet to surround at least one side of the graphite sheet; And
Including; providing an adhesive layer on one or both sides of the graphite sheet, and providing a support member and an electromagnetic wave shielding layer on the upper and lower portions thereof; and
The reinforcing member is disposed to surround at least one side of the graphite sheet with a width of 1 to 15 mm,
The average thickness of the reinforcing member is 53 to 147% of the average thickness of the graphite sheet electromagnetic shielding-heat-radiating composite sheet manufacturing method.

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