KR20160148487A - Excellent interlayer adhesive graphite sheet for composite sheet with EMI shield and heat radiation, Composite sheet with EMI shield and heat radiation containing the same and Manufacturing method thereof - Google Patents

Abstract

The present invention relates to a graphite sheet having excellent interlayer adhesive strength, an electromagnetic wave shielding and heat radiating composite sheet comprising the same and a manufacturing method thereof. As a graphite sheet having a through-hole with a sectional shape of specific heteromorphism is introduced into a thermal diffusion layer, the electromagnetic wave shielding and heat radiating composite sheet is to be a thin film and has high thermal diffusion ability, electromagnetic wave shielding ability and thermal resistance impact while having excellent adhesive strength without an additional adhesive layer between a second electromagnetic wave shielding layer and the graphite sheet.

Description

TECHNICAL FIELD [0001] The present invention relates to a graphite sheet for electromagnetic shielding and heat-radiating composite sheets excellent in interlaminar adhesive strength, an electromagnetic shielding and heat-radiating composite sheet containing the same, and a method for manufacturing the composite shield sheet and composite sheet lt; RTI ID = 0.0 > and / or < / RTI &

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a graphite sheet for electromagnetic shielding and heat-radiating composite sheets and a composite sheet including the same, and more particularly to a graphite sheet for electromagnetic shielding and heat- The present invention relates to a graphite sheet capable of providing a sheet, a composite sheet using the same, and a method of manufacturing the same.

[0002] With the recent trend toward high performance and light weight and short life of electrical and electronic devices, there has been a steady increase in demand for heat-radiating sheets capable of effectively dissipating heat generated from heat sources such as semiconductor components and light- Functionalization is required.

Generally, a heat-radiating sheet uses copper foil, a copper foil / graphite laminate, and a graphite sheet. The copper foil has both heat dissipation properties and electromagnetic shielding characteristics. However, when the thickness is thick, flexibility is insufficient. It is insignificant and has a high density, which limits its weight. If the thickness exceeds about 50 탆, flexibility is insufficient, and thus there is a limit to the application as a heat radiation sheet having a complicated shape.

In addition, although a commercial product made of various materials is widely used as an electromagnetic wave shielding sheet for shielding electromagnetic waves, a conventional electromagnetic wave shielding sheet has a low thermal conductivity and can not sufficiently obtain a heat radiation effect, Is being developed. For example, Korean Patent No. 10-1457914 discloses a thermal diffusion sheet having an electromagnetic wave absorbing layer in which an electromagnetic wave absorbing layer is laminated on one surface or both surfaces of a thermal diffusion sheet composed of a metal foil layer and a thermal diffusion layer. It is disadvantageous in that it is thinned. Therefore, there are technical limitations in application to a portable electronic device such as a smart phone, which is a small electronic device, and there is a problem that flexibility is greatly reduced.

2. Description of the Related Art In recent years, portable electronic devices have been required to be flexible and thin. As a result, the heat radiation sheet and the electromagnetic wave shielding sheet which are essential parts used therefor have been increasingly demanded for flexibility and thinness.

U.S. Published Patent Application No. 2007-0246208 (published on October 25, 2007)

SUMMARY OF THE INVENTION The present invention has been conceived to solve the problems as described above, and it is an object of the present invention to provide a graphite sheet having a specific type of through hole introduced into a thermal diffusion layer, The present invention provides an electromagnetic wave shielding and heat-radiation composite sheet which is flexible and slim while preventing separation of the thermal diffusion layer and other bonded layers when bent, and a method of manufacturing the same.

In order to solve the above problems, the graphite sheet of the present invention having excellent interlayer adhesion is a graphite sheet having a plurality of through holes.

As a preferred embodiment of the present invention, the through holes of the graphite sheet may have a cross-sectional shape having a profile of the following formula (1).

[Equation 1]

0.500 ≤

In the above equation (1), the mold-outline is (inner width of the shape / circumference length of the shape) ^1/2 .

In one preferred embodiment of the present invention, the cross-sectional shape of the through-hole may include at least one selected from a circle, an ellipse, a +, a x, a , a ┏,

In the preferred embodiment of the present invention, when the cross-sectional shape of the through-hole is circular, the diameter of the ellipse is 1: 2 to 10 and the diameter of the ellipse is 1: 2 to 10, The diameter ratio of the circumscribed circle may be 1: 2 ~ 10.

In one preferred embodiment of the present invention, the through hole area of the graphite sheet may be 2% to 30%, preferably 3.5% to 15% of the total area of the upper or lower surface of the graphite sheet.

In one preferred embodiment of the present invention, the graphite sheet may be a graphite sheet containing at least one of pyrolytic graphite and graphitized polyimide.

Further, the present invention provides an electromagnetic wave shielding and heat radiation composite sheet in which the graphite sheet is introduced into a thermal diffusion layer, wherein a first electromagnetic wave shielding layer, an adhesive layer, a thermal diffusion layer including the graphite sheet and a second electromagnetic wave shielding layer are stacked And the inside of the through hole is filled with an adhesive derived from the second electromagnetic wave shielding layer.

In a preferred embodiment of the present invention, the inside of the through-hole is filled with an adhesive component derived from the second electromagnetic wave shielding layer; Or an adhesive derived from the second electromagnetic wave shielding layer and an adhesive derived from the adhesive layer may be filled.

In a preferred embodiment of the present invention, the adhesive component derived from the second electromagnetic wave shielding layer may be a non-adhesive component.

In one preferred embodiment of the present invention, the first electromagnetic wave shielding layer may be a copper foil or an aluminum foil.

In one preferred embodiment of the present invention, the adhesive layer may include a thermosetting epoxy resin, a rubber binder, a silane coupling agent, a fluorine-based surfactant, a curing agent, a curing accelerator, a flame retardant and a humidifier.

In one preferred embodiment of the present invention, the adhesive layer is composed of 25 to 100 parts by weight of a rubber binder, 1 to 10 parts by weight of a silane coupling agent, 0.01 to 2 parts by weight of a fluorinated surfactant, a curing agent 5 To 20 parts by weight, 1 to 5 parts by weight of a curing accelerator, 30 to 60 parts by weight of a flame retardant and 0.5 to 10 parts by weight of a moisture-proofing agent.

In a preferred embodiment of the present invention, the adhesive layer may further include a thermally conductive filler.

As a preferred embodiment of the present invention, the thermally conductive filler may be a graphite powder, a carbon nanotube (CNT), a carbon black powder, a carbon fiber, a ceramic powder, and a metal And may include at least one selected from metal powder.

In a preferred embodiment of the present invention, the second electromagnetic wave shielding layer may be a cured product of a mixed resin including a thermosetting epoxy resin, a rubber binder, a silane coupling agent, a fluorine surfactant, a soft magnetic powder, a curing agent and a curing accelerator .

In one preferred embodiment of the present invention, the mixed resin used for forming the second electromagnetic wave shielding layer comprises 160 to 350 parts by weight of a rubber binder, 4 to 25 parts by weight of a silane coupling agent, 0.5 to 5 parts by weight of an activator, 700 to 1,500 parts by weight of a soft magnetic powder, 2 to 30 parts by weight of a curing agent and 1 to 25 parts by weight of a moisture resistant agent.

In one preferred embodiment of the present invention, the soft magnetic powder is selected from the group consisting of Fe-Si-Al alloys, Fe-Si-Cr alloys, Fe-Si-B alloys, highflux, permalloy alloys , A Ni-Zn ferrite alloy, and a Mn-Zn ferrite alloy.

In one preferred embodiment of the present invention, the soft magnetic powder may have an average particle diameter of 20 to 100 mu m.

In one preferred embodiment of the present invention, the second electromagnetic wave shielding layer is made of graphite powder, carbon nanotube (CNT), carbon black powder, carbon fiber, ceramic powder And a metal powder. The thermally conductive filler may further include at least one selected from the group consisting of a metal powder and a metal powder.

As a preferred embodiment of the present invention, the total thickness of the electromagnetic wave shielding and heat radiation composite sheet of the present invention may be 40 탆 to 400 탆, preferably 60 탆 to 300 탆.

In one preferred embodiment of the present invention, the first electromagnetic wave shielding layer has an average thickness of 5 탆 to 70 탆, the adhesive layer has an average thickness of 2 탆 to 25 탆, the thermal diffusion layer has an average thickness of 10 탆 to 40 탆, May be an average thickness of 30 mu m to 300 mu m.

As a preferred embodiment of the present invention, in the electromagnetic wave shielding and heat radiation composite sheet of the present invention, the peeling strength of the thermal diffusion layer with respect to the second electromagnetic wave shielding layer is 390 gf / cm ² To 770 gf / cm < ² >.

In one preferred embodiment of the present invention, each of the through holes of the thermal diffusion layer can have a peel strength of 50 to 1,500 gf / hole when the peel strength is measured according to JIS C 6741.

As a preferred embodiment of the present invention, the electromagnetic wave shielding and heat radiation composite sheet of the present invention may have a horizontal thermal conductivity of 100 to 1,000 W / m? K and a vertical thermal conductivity of 1 to 15 W / m? K.

Another object of the present invention is to provide a method for producing an integrated composite sheet of the present invention in various forms as described above, wherein a first electromagnetic wave shielding layer, an adhesive layer, a thermal diffusion layer including the graphite sheet and a second electromagnetic wave shielding layer are laminated To the hot press equipment; A second step of heating and pressing the laminate under a pressure of 145 to 160 占 폚 and 45 to 60 kgf / cm2 to perform a hot press process; And a third step of cooling the hot press and then separating the composite sheet integrated from the hot press.

As a preferred embodiment of the present invention, the heating in the second step may be carried out by heating a hot press at 10 ° C to 35 ° C at a rate of 3 ° C / minute to 5 ° C / minute to 145 ° C to 160 ° C.

As a preferred embodiment of the present invention, the cooling in the three stages may be performed by cooling a hot press at 145 ° C to 160 ° C at a rate of 3 ° C / min to 5 ° C / min to 10 ° C to 35 ° C.

Another object of the present invention is to provide a coverlay film and / or a flexible circuit board comprising the integrated composite sheet of the present invention in various forms described above.

Further, it is desirable to provide an electronic apparatus, preferably a portable electronic apparatus, including the integral composite sheet of the present invention.

In a preferred embodiment of the present invention, the electronic device may be a flexible electronic device.

The integrated composite sheet of the present invention maximizes the horizontal thermal conductivity (horizontal thermal diffusivity) while minimizing the vertical thermal conductivity by introducing a graphite sheet having a plurality of through holes satisfying specific conditions, and has an excellent electromagnetic wave shielding effect. Further, the integrated composite sheet of the present invention does not have a separate adhesive layer between the graphite sheet and the second electromagnetic wave shielding layer, and thus can realize a thin thickness. Further, the integrated composite sheet of the present invention has a high peeling strength between the second electromagnetic wave shielding layer and the thermal diffusion layer, It is possible to provide a monolithic composite sheet having excellent flaking strength and excellent impact resistance and flexibility.

1 is a schematic cross-sectional view of an electromagnetic shielding and heat-dissipating function integrated composite sheet according to a preferred embodiment of the present invention.
FIG. 2 is a schematic view of a preferred embodiment of a thermal diffusion layer having a plurality of through holes constituting an integrated electromagnetic shielding and heat radiation function composite sheet according to the present invention.
Figs. 3 (a) to 3 (c) are schematic views of a form in which an adhesive component derived from the heat-radiating adhesive layer and / or the second electromagnetic wave shielding layer is filled in the through-hole of the thermal diffusion layer.
FIG. 4 is a schematic view of a digitizer module incorporating the electromagnetic shielding and heat dissipation function integrated composite sheet 100 of the present invention.

Hereinafter, the present invention will be described in more detail.

Conventionally, the heat-radiating sheet and / or the composite sheet are made of a heat-radiating material, a copper foil, a copper foil / graphite laminate and a graphite sheet. The copper foil has both heat dissipation properties and electromagnetic shielding characteristics. However, , The thermal conductivity in the horizontal direction is not good compared with the graphite, and the density is high, so there is a limit in weight reduction. If the thickness exceeds about 50 탆, flexibility is insufficient, and thus there is a limit to the application as a heat radiation sheet having a complicated shape. Further, the copper foil and the graphite layered body require an adhesive layer between the copper foil and the graphite layered body, thereby causing a problem of deterioration of the heat conduction characteristics. Further, the graphite has a problem that interlayer delamination occurs in the graphite itself.

 Commercial products made of various materials are widely used as electromagnetic wave shielding sheets for shielding electromagnetic waves. However, conventional electromagnetic wave shielding sheets have low thermal conductivity and can not sufficiently obtain a heat radiation effect. Therefore, it is required to simultaneously realize a heat radiation effect and an electromagnetic wave shielding effect.

1, the present invention includes a graphite sheet 10 having a first electromagnetic wave shielding layer 40, an adhesive layer 20, and a plurality of through holes 1, 2, 3, (Hereinafter referred to as "composite sheet") having a structure in which a thermal diffusion layer and a second electromagnetic wave shielding layer 30 are laminated in order.

Since the planar size of the graphite sheet (or thermal diffusion layer) is smaller than the planar size of the first electromagnetic wave shielding layer and the second electromagnetic wave shielding layer, the planar size of the first electromagnetic wave shielding layer and the second electromagnetic wave shielding layer 2 electromagnetic wave shielding layer, and when there is no adhesive component originating from the adhesive and / or the second electromagnetic wave shielding layer, the thickness of the thermal diffusion layer, as viewed from the side of the integral composite sheet, There is a spacing space between the first electromagnetic wave shielding layer and the second electromagnetic wave shielding layer.

2 and 3, a plurality of through holes (1, 2, 3, 4) exist in the thermal diffusion layer or the graphite sheet 10, and the through holes and the first electromagnetic wave The space between the shielding layer and the second electromagnetic wave shielding layer is filled with an adhesive and / or an adhesive component derived from the second electromagnetic wave shielding layer, whereby the first electromagnetic wave shielding layer 40, the thermal diffusion layer 10, (30) are combined and integrated. More specifically, the adhesive layer is in a semi-cured state and the second electromagnetic wave shielding layer is also in a semi-cured state. Therefore, when heat and pressure are applied by hot pressing after stacking the respective layers, (See FIG. 3 (a) to FIG. 3 (c)), the adhesive agent 20 of the adhesive layer is also filled in the spacing space with the penetrating hole 20 ' .

Each layer constituting the integral composite sheet 100 of the present invention will be described more specifically.

First, the first electromagnetic wave shielding layer is a material having a heat dissipation and an electromagnetic wave shielding function, and a metal foil commonly used in the art can be used. As a preferable example, a copper foil or an aluminum foil can be used .

The first electromagnetic wave shielding layer 40 preferably has an average thickness of 5 to 70 탆, preferably 8 to 40 탆, more preferably 8 to 35 탆. At this time, the average thickness of the first electromagnetic wave shielding layer If it is less than 5 mu m, there may be a problem that an appearance problem occurs and a tear phenomenon occurs. If it exceeds 70 mu m, it may be difficult to form a thin film and a product flexibility may be lowered.

Next, the adhesive layer (or adhesive) 20 will be described.

The adhesive layer serves to bond the first electromagnetic wave shielding layer and the thermal diffusion layer and / or the first electromagnetic wave shielding layer, the thermal diffusion layer and the second electromagnetic wave shielding layer to each other, and the heat transfer from the first electromagnetic wave shielding layer to the thermal diffusion layer It is advisable to use a highly heat-resistant adhesive that can be made well. Preferably, the adhesive layer has a melting point higher than that of the second electromagnetic wave shielding layer component. The adhesive layer (or adhesive) may be formed of a thermosetting resin, a rubber binder, a silane coupling agent, a fluorine surfactant, a curing agent, a curing accelerator, . ≪ / RTI >

Among the components of the adhesive layer, the thermosetting resin may include at least one of a thermosetting epoxy resin, a thermosetting phenoxy resin, a thermosetting amino resin, a thermosetting polyester resin and a thermosetting polyurethane resin, and preferably a thermosetting epoxy resin can be used , And more preferably one or two or more selected from a bisphenol A epoxy resin, a bisphenol F epoxy resin, a novaleak epoxy resin and a halogen-containing epoxy resin.

When two or more kinds of thermosetting epoxy resins are used in combination, it is preferable to mix bisphenol A epoxy resin and novaleak epoxy resin at a weight ratio of 1: 0.15 to 0.4, preferably 1: 0.18 to 0.35, It is advantageous in terms of improvement and adhesion.

The rubber binder among the components of the adhesive layer may play a role in imparting bending resistance and may include one or more of acryl rubber, silicone rubber, carboxylated nitrile elastomer and phenoxy, Preferably one or two or more of acrylic rubber and silicone rubber. Carboxylic elastomer may be used, and it is preferable to use a carboxylnitrile elastomer. The carboxyl-series elastomer preferably has a weight-average molecular weight of 180,000 to 350,000, preferably a weight-average molecular weight of 210,000 to 280,000, more preferably a weight-average molecular weight of 215,000 to 255,000, And the heat resistance of the adhesive layer. The rubber binder may be used in an amount of 25 to 100 parts by weight, preferably 35 to 80 parts by weight, based on 100 parts by weight of the thermosetting resin. When the rubber binder is used in an amount of less than 25 parts by weight, When the composite sheet is bent, the first electromagnetic wave shielding layer and the thermal diffusion layer bonding part may be partially peeled off. If the composite sheet is used in excess of 100 parts by weight, the amount of other components in the adhesive layer may decrease, There is a problem that the adhesiveness of the adhesive layer may be reduced.

Among the components of the adhesive layer, the silane coupling agent plays a role of dispersing the particles and can be a conventional silane coupling agent used in the art, preferably glycidoxy (C2 to C5 alkyl) trialkoxysilane (Glycidoxy (C2 C5 alkyl) trialkoxysilane, vinyltri (C2-C5 alkoxy) silane, and aminoethylaminopropylsilane triol, and more preferably at least one selected from glycidoxyethyl At least one member selected from the group consisting of trimethoxysilane, glycidoxypropyltrimethoxysilane, glycidoxypropylethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, and aminoethylaminopropylsilane triol The amount of the silane coupling agent to be used is 1 to 10 parts by weight based on 100 parts by weight of the thermosetting resin, When the silane coupling agent is used in an amount of less than 1 part by weight, the amount of the silane coupling agent used is too small to exhibit the effect of dispersing the particles. When the silane coupling agent is used in an amount exceeding 10 parts by weight, There is a problem that particle aggregation occurs, so it is preferable to use it within the above range.

Among the components of the adhesive layer, the fluorine-based surfactant plays a role of improving the coating property by lowering the surface tension. The fluorine-based surfactant generally used in the art can be used, and preferably a fluoroaliphatic polymeric ester Specific examples thereof include FC4430 of 3M, Novec 4300 of Du Pont, DuPont Capstone of DuPont, and the like. The amount of the fluorinated surfactant to be used may be 0.01 to 2 parts by weight, preferably 0.02 to 1.2 parts by weight, based on 100 parts by weight of the thermosetting resin. When the fluorinated surfactant is used in an amount of less than 0.01 part by weight, It may not be effective to improve the coating property. If it is used in excess of 2 parts by weight, there may be a problem that the adhesive strength is lowered.

Among the components of the adhesive layer, at least one of an amine type hardener, an anhydride type hardener and a phenol type hardener may be used as the curing agent, preferably an amine type curing agent an amine type hardener, and an anhydride type hardener. Specific examples thereof include 4,4'-diaminodiphenlysulfone (4,4'-diaminodiphenlysulfone) as a curing agent . The curing agent may be used in an amount of 5 to 20 parts by weight, preferably 8 to 17 parts by weight, based on 100 parts by weight of the thermosetting resin. If the amount of the curing agent is less than 5 parts by weight, durability may be reduced. If it is used in an amount exceeding 20 parts by weight, there may arise a problem that the heat insulation adhesive strength is lowered.

Among the components of the adhesive layer, the curing accelerator may include at least one of an aromatic amine, an aliphatic amine, and an aromatic tertiary amine, and may preferably include at least one of an aromatic amine and an aromatic tertiary amine. The curing accelerator may be used in an amount of 1 to 5 parts by weight, preferably 1.5 to 4.5 parts by weight based on 100 parts by weight of the thermosetting resin. If the amount of the curing accelerator is less than 1 part by weight, the curing speed of the adhesive is too slow, If it is used in an amount exceeding 5 parts by weight, the adhesive layer may be cured too quickly, and the heat-curing layer may be completely cured before hot pressing.

Among the components of the adhesive layer, the flame retardant is one for obtaining a flame retardant effect of the product, and may be a general one used in the art. Preferably, the flame retardant is one or two or more selected from phosphorus flame retardants, inorganic flame retardants, For example, Clariant EXOLIT OP 935, H42M of Showa Denko Corp., H32 of Showa Denko KK and H43M of Showa Denko KK can be used. The flame retardant may be used in an amount of 30 to 60 parts by weight, preferably 35 to 55 parts by weight, based on 100 parts by weight of the thermosetting resin. When the amount of the flame retardant is less than 30 parts by weight, If it is used in an amount exceeding 60 parts by weight, there is a problem that the adhesive strength of the product may be lowered due to the excessive use of the flame retardant component.

Among the components of the adhesive layer, the moisture absorbing agent is used for controlling the water content in the adhesive layer and for controlling the viscosity of the adhesive, and it is possible to use any of those commonly used in the art. Preferred examples thereof include aluminum sulfate, latex, silicone emulsion, ), A hydrophobic polymer emulsion, a silicone-based moisture-proofing agent, and the like, or a mixture of two or more thereof. The amount of the humectant to be used may be 0.5 to 10 parts by weight, preferably 1.5 to 8 parts by weight, based on 100 parts by weight of the thermosetting resin. If the amount of the humectant is less than 0.5 parts by weight, If it is used in excess of 10 parts by weight, it may be difficult to control the proper amount of water in the adhesive layer due to overuse.

On the other hand, the adhesive layer (or adhesive) of the present invention may further include a thermally conductive filler and / or a dispersant. The thermally conductive filler may be one or two of graphite powder, carbon nanotube (CNT), carbon black, carbon fiber, ceramic and metal powder. Or a mixture of two or more species of graphite powder, ceramics and metal powder may be preferably used. When the thermally conductive filler is further used, it may contain 45 to 1,100 parts by weight, preferably 75 to 800 parts by weight, relative to 100 parts by weight of the thermosetting resin. If the thermally conductive filler is used in excess of 1100 parts by weight, The vertical thermal conductivity of the composite sheet can be greatly increased.

The thermally conductive filler preferably has an average particle diameter of 3 to 25 占 퐉. If the average particle diameter is less than 3 占 퐉, it may be difficult to disperse the particles. If the average particle diameter exceeds 25 占 퐉, It is preferable to use a thermally conductive filler having a particle size within the above range.

The dispersant may be any of those generally used in the art, and preferably an acrylic block amine dispersant may be used.

The viscosity and solid content of the adhesive can be adjusted by introducing a mixture of the above-mentioned curable resin, rubber binder, silane coupling agent, fluorine surfactant, curing agent, curing accelerator, flame retardant and humidifier into an organic solvent. And the shape of the crosspieces, the surface state of the composition for forming a heat-radiating adhesive layer is improved, and the adhesion of the substrate and the orientation of the particles can be controlled. At this time, the organic solvent may be used alone or in combination of two or more of methyl ethyl ketone, toluene, tetrahydrofuran (THF), and cyclohexanone.

The adhesive formed in such a composition and composition ratio is coated (or coated) on the top of the first electromagnetic wave shielding layer, followed by drying and semi-hardening to form an adhesive layer. At this time, It is preferable to apply the adhesive layer so that the adhesive layer has an average thickness of 2 탆 to 25 탆, preferably an average thickness of 4 to 15 탆, based on the sheet. At this time, if the average thickness of the adhesive layer in the composite sheet is less than 2 탆, the bonding force (or adhesive force) between the first electromagnetic wave shielding layer and the thermal diffusion layer may be lowered.

Next, a thermal diffusion layer (graphite sheet) 10 provided with through-holes constituting the composite sheet of the present invention will be described.

The thermal diffusion layer is composed of a graphite sheet (or film) having a through hole formed therein. Through this through hole, the first electromagnetic wave shielding layer and the second electromagnetic wave shielding layer disposed under and under the thermal diffusion layer are integrated and the second electromagnetic wave shielding layer It is possible to omit a separate adhesive layer between the thermal diffusion layers, thereby making it possible to reduce the thickness of the composite sheet.

In addition, the graphite sheet uses a graphite sheet in which a through hole is formed so as to have a distribution curve satisfying the following equation (1) so as to realize an excellent thermal conductivity and a high peeling strength between the second electromagnetic wave shielding layer and the thermal diffusion layer.

[Equation 1]

0.500 ≤ 1 ≤ 1.300, preferably 0.520 ≤

In the above equation (1), the mold-outline is (inner width of the shape / circumference length of the shape) ^1/2 .

In the above equation 1, if the degree of differentiation is less than 0.500, the overall thermal diffusibility is excellent, but the peeling strength such as peel strength per through hole may be low and the peeling strength between the second electromagnetic wave shielding layer and the thermal diffusion layer may be low. But there is a problem that the vertical thermal conductivity increases.

The cross-sectional shape of the through-hole is a cross-sectional shape satisfying the above-mentioned schematic diagram, and may have one species or two or more species selected from a circle, an ellipse, a +, a x, And preferably one species or two or more species selected from the group consisting of a circle, an ellipse, a + type and a ┏ type.

 As shown in Fig. 2 (b), through holes can be formed on the graphite sheet by combining various sectional shapes. In order to facilitate understanding, for example, when the cross-sectional shape of the through-hole is circular, the diameter is 0.5 to 8 mm in average diameter, the diameter ratio of the inscribed circle and the circumscribed circle is 1: 2 to 10, The diameter ratio of the circumscribed circle may be 1: 2 ~ 10.

More specifically, in the case of a circular through hole, the average diameter of the circular cross-sectional shape may be 0.5 mm to 8 mm, preferably 0.5 mm to 5 mm, more preferably 1 to 4 mm, and if the average diameter of the through holes is 0.5 mm, the durability against thermal shock due to the increase in the number of the through holes provided with the thermal diffusion layer may be reduced, and the filling rate of the adhesive component filled in the through holes may be decreased to reduce the durability against thermal shock If the thickness exceeds 8 mm, the thermal diffusing performance in the horizontal direction of the thermal diffusion layer may decrease, and the shape retention ability of each layer may be decreased during the production of the composite sheet, resulting in an increase in the defective ratio. There may be a problem that the peel strength is lowered.

The distance between the through holes may vary depending on the size of the through hole. For example, when the diameter of the through hole is less than 1 mm, the distance between the through holes is 4 mm to 16 mm in the major axis direction, A distance of 18 mm, preferably a distance of 6 mm to 14 mm in the major axis direction and a distance of 8 mm to 14 mm in the minor axis direction, securing the horizontal thermal conductivity of the thermal diffusion layer, It is advantageous in terms of securing adequate adhesion between the shielding layer and the thermal diffusion layer and preventing delamination of the thermal diffusion layer itself.

The through hole area of the thermal diffusion layer (graphite sheet) is 2% to 30%, preferably 3.5% to 15%, and more preferably 3.5% to 10% of the total area of the upper or lower surface of the thermal diffusion layer. At this time, if the through hole area is less than 2%, there is a problem in that the peeling strength between the second electromagnetic wave shielding layer and the thermal diffusion layer is low. If it exceeds 30%, the peeling strength is excellent, but the vertical thermal conductivity may increase , There may be a problem that the thermal diffusion performance is remarkably reduced. Therefore, it is preferable to form the through holes so as to have the above-mentioned area ratio.

The graphite sheet (or film) constituting the thermal diffusion layer may be a graphite sheet common to those skilled in the art and preferably a graphite sheet containing at least one of pyrolytic graphite and graphitized polyimide. .

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

The graphitized polyimide may be prepared through the following graphitization process.

First, as a preparation step of the graphitization process, polyimide may be put into a firing furnace by being laminated on a natural graphite sheet. Such a preparation step may be carried out in order to prevent fusion of the films, in which the polyimide may have a film form.

Next, the carbonization step of the polyimide can be carried out at a temperature of 600 ° C to 1,800 ° C for 2 to 7 hours in the first step of the graphitization process. This carbonization step removes nitrogen and hydrogen, as well as carbon in the polyimide.

Finally, as a second step in the graphitization process, a heat treatment step can be performed at a temperature between 2,000 ° C and 3,200 ° C. This heat treatment step can lead to different alignments of the carbon atoms. Specifically, there may be pores between the stacks of carbon in the polyimide after the first step. By passing through a rolling roll at a temperature of 2,000 DEG C to 3,200 DEG C, pore removal and density are increased, This maximized graphitized polyimide can be produced.

Next, the second electromagnetic wave shielding layer 30 constituting the composite sheet of the present invention will be described.

The second electromagnetic wave shielding layer not only shields electromagnetic waves but also includes a layer capable of absorbing electromagnetic waves, including a thermosetting epoxy resin, a rubber binder, a silane coupling agent, a fluorine surfactant, a soft magnetic powder, a hardener and a hardening accelerator A cured product of a mixed resin, and may be a metal sheet, for example.

In the second electromagnetic wave shielding layer, a part of the adhesive component in the second electromagnetic wave shielding layer is melted and filled in the through hole of the thermal diffusion layer during the hot press process for manufacturing the composite sheet. Since the melting point of the second electromagnetic wave shielding layer is lower than that of the adhesive layer, the adhesive component to be filled in the through hole of the thermal diffusion layer is larger in the amount of the adhesive component originating from the second electromagnetic wave shielding layer than that of the adhesive layer- . Therefore, it is advantageous that the second electromagnetic wave shielding layer and the mixed resin constituting the second electromagnetic wave shielding layer have a melting point equal to or lower than the hot press process temperature (145 DEG C to 160 DEG C), or preferably a somewhat lower melting point.

Among the mixed resin components used for forming the second electromagnetic wave shielding layer, the thermosetting epoxy resin may be a mixture of at least one selected from the group consisting of bisphenol A epoxy resin, bisphenol F epoxy resin, novolak epoxy resin and Br-containing epoxy resin .

The rubber binder of the mixed resin component may be the same as or different from the rubber binder of the adhesive layer, and may include at least one of acrylic rubber, silicone rubber, carboxylated nitrile elastomer, and phenoxy And preferably one or two or more of acrylic rubber and silicone rubber may be included. At this time, the carboxylnitrile elastomer is the same as mentioned in the description of the adhesive layer. The amount of the rubber binder used in the mixed resin may be 160 to 350 parts by weight, preferably 180 to 300 parts by weight, more preferably 200 to 280 parts by weight, based on 100 parts by weight of the thermosetting epoxy resin. If the amount of the binder used is less than 160 parts by weight, flexibility of the second electromagnetic wave shielding layer may be deteriorated, and when the composite sheet is bent, there may be a problem that the second electromagnetic wave shielding layer and the thermally- The use of the second electromagnetic wave shielding layer is uneconomical and the use of relatively different composition is reduced, and the electromagnetic wave shielding performance of the second electromagnetic wave shielding layer and the adhesive force with the thermal diffusion layer may be lowered.

Among the mixed resin components, the silane coupling agent plays a role of dispersing the particles. Typical silane coupling agents used in the art can be used, and preferably glycidoxy (C2 to C5 alkyl) trialkoxysilane ( At least one selected from the group consisting of glycidoxy (C2-C5 alkyl) trialkoxysilane, vinyltri (C2-C5 alkoxy) silane and aminoethylaminopropylsilane triol, But are not limited to, singly or in combination of two or more selected from the group consisting of glycidoxypropyltrimethoxysilane, glycidoxypropyltrimethoxysilane, glycidoxypropylethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, The amount of the silane coupling agent to be used may be 4 to 4 parts by weight per 100 parts by weight of the thermosetting epoxy resin. To 25 parts by weight, preferably 4 to 18 parts by weight, more preferably 4 to 12 parts by weight may be used. When the silane coupling agent is used in an amount of less than 4 parts by weight, the amount of the silane coupling agent used is too small, If it is used in an amount exceeding 25 parts by weight, there may be a problem of aggregation due to the reaction between the coupling agents.

Among the mixed resin components, the fluorine-based surfactant plays a role of improving the coating property by lowering the surface tension, and it is possible to use a general one used in the art, preferably a fluoroaliphatic polymeric ester Specific examples thereof include FC4430 of 3M, Novec 4300 of Du Pont, DuPont Capstone of DuPont, and the like. The amount of the fluorinated surfactant to be used may be 0.5 to 5 parts by weight, preferably 0.5 to 3 parts by weight, based on 100 parts by weight of the thermosetting resin. When the fluorinated surfactant is used in an amount of less than 0.5 parts by weight, The coating property may not be good, and when it is used in an amount exceeding 5 parts by weight, there may be a problem that the adhesion with the thermal diffusion layer is lowered.

Mixed Resin Component The soft magnetic powder is at least one selected from the group consisting of Fe-Si-Al alloys, Fe-Si-Cr alloys, Fe-Si-B alloys, highflux, permalloy alloys, ferrite and Mn-Zn ferrite. The Fe-Si-Al alloy, the Fe-Si-Cr alloy and the Fe-Si-B alloy May be used alone or in combination of two or more. The soft magnetic powder may be used in an amount of 700 to 1,500 parts by weight, preferably 850 to 1,350 parts by weight, more preferably 900 to 1,300 parts by weight, based on 100 parts by weight of the thermosetting epoxy resin. If the amount is less than 700 parts by weight There may be a problem that the electromagnetic wave absorbing performance due to reduction of the permeability is lowered. If it is used in excess of 1,500 parts by weight, the electromagnetic wave shielding effect is excellent, but the mechanical properties such as flexibility may be deteriorated.

The soft magnetic powder preferably has an average particle diameter of 20 to 100 mu m, preferably 30 to 70 mu m. If the average particle diameter is less than 20 mu m, there is a problem that the electromagnetic wave shielding or absorption performance is deteriorated When the average particle size exceeds 100 탆, the coating property may be deteriorated. Therefore, it is preferable to use a soft magnetic powder having a particle size within the above range.

Mixed resin component The above-mentioned curing agent may be the same as or different from the curing agent of the adhesive layer, and preferably the same kind of curing agent is used. The curing agent may be used in an amount of 2 to 30 parts by weight, preferably 3 to 20 parts by weight, more preferably 4 to 15 parts by weight, based on 100 parts by weight of the thermosetting epoxy resin. If the amount of the curing agent is less than 2 parts by weight There may be a problem that the curing rate becomes too long and workability is deteriorated. If it is used in excess of 30 parts by weight, the adhesive component filled in the through hole may be decreased during the hot press process, and the adhesive force with the thermal diffusion layer may be lowered .

The humidity resistant agent is for controlling the water content in the second electromagnetic wave shielding layer and controlling the viscosity of the adhesive. Preferable examples thereof include aluminum sulfate, latex, silicone emulsion, poly (organosiloxane), hydrophobic polymer emulsion, These can be used singly or in combination of two or more. The amount of the humectant to be used may be 1 to 25 parts by weight, preferably 5 to 20 parts by weight, based on 100 parts by weight of the thermosetting resin. If the amount of the humectant is less than 1 part by weight, If it is used in an amount exceeding 25 parts by weight, it may be difficult to control the proper amount of water of the second electromagnetic wave shielding layer due to overuse.

The mixed resin may be prepared by mixing an organic solvent with a mixture of the thermosetting epoxy resin, the rubber binder, the silane coupling agent, the fluorine surfactant, the soft magnetic particles, the curing agent and the moisture absorber described above to adjust the viscosity and the viscosity of the composition for forming the second electromagnetic wave- The solids content can be controlled. At this time, the organic solvent used may include at least one of methyl ethyl ketone, toluene, tetrahydrofuran (THF), and cyclohexanone.

The mixed resin is preferably adjusted to have a viscosity of 800 to 1,200 cps at 25 ° C and a solid content of 40 to 60% by weight, preferably a viscosity of 950 to 1,200 cps at 25 ° C and a solid content of 48 to 56% .

The mixed resin having such composition and composition ratio is applied (or coated) on the top of the thermal diffusion layer, followed by drying and semi-curing to form a second electromagnetic wave shielding layer on the thermal diffusion layer. In the composite sheet of the present invention, The electromagnetic wave shielding layer may have an average thickness of 30 mu m to 300 mu m, preferably 30 mu m to 200 mu m, and more preferably 35 mu m to 100 mu m. At this time, if the average thickness of the second electromagnetic wave shielding layer is less than 30 mu m, the electromagnetic wave shielding effect may be insufficient. If the average thickness is more than 300 mu m, it is disadvantageous in view of thinness and is not economical.

The composite sheet of the present invention comprises a first step of injecting a laminate obtained by laminating a first electromagnetic wave shielding layer, an adhesive layer, a thermal diffusion layer including a graphite sheet provided with a plurality of through holes, and a second electromagnetic wave shielding layer into a hot press equipment; A second step of heating and pressing the laminate under a pressure of 145 to 160 占 폚 and 45 to 60 kgf / cm2 to perform a hot press process; And a third step of cooling the hot press and then separating the composite sheet integrated from the hot press.

In the first step, the compositions and composition ratios of the first electromagnetic wave shielding layer, the adhesive layer, the thermal diffusion layer and the second electromagnetic wave shielding layer are the same as those described above.

If the temperature of the hot press process is less than 145 캜 in step 2, the adhesive component of the second electromagnetic wave shielding layer and / or the adhesive layer is not sufficiently melted and the fill factor in the through hole of the graphite layer may be lowered. 2 The adhesive component in the electromagnetic wave shielding layer melts too much, so that it is difficult to maintain the shape of the second electromagnetic wave shielding layer and mechanical properties may be deteriorated.

If the pressure is less than 45 kgf / cm < 2 > during the two-step hot pressing process, the amount of the adhesive component in the second electromagnetic wave shielding layer and / or the adhesive component of the adhesive layer may be small, Exceeding is uneconomical.

It is preferable that the hot press process is performed by heating and pressing the laminate under the above pressure and temperature for 40 minutes to 80 minutes, preferably 50 minutes to 70 minutes. At this time, Minute, the adhesive component does not sufficiently flow out from the second electromagnetic wave shielding layer, so that there is a problem that the amount of filling into the hole of the thermal diffusion layer is small and the peel strength is lowered, and it is uneconomical to exceed 70 minutes.

The heating in the second step may be carried out by warming a hot press at 10 ° C to 35 ° C at a rate of 3 ° C / min to 5 ° C / min to 145 ° C to 160 ° C.

The three-step cooling may be performed by cooling the hot press at 145 ° C to 160 ° C at a rate of 3 ° C / minute to 5 ° C / minute to 10 ° C to 35 ° C.

The composite sheet of the present invention produced by the above-described structure, composition and composition ratio of each layer and the production method of the present invention has a horizontal thermal conductivity of 100 to 1,000 W / m · k and a vertical thermal conductivity of 1 to 15 W / m · k or less And preferably has a horizontal thermal conductivity of 200 to 1,000 W / m · k and a vertical thermal conductivity of 1 to 10 W / m · k or less.

In a composite sheet of the present invention on the basis of JIS C 6741 specifications for peel strength of the thermal diffusion layer 180 ° peel test (180 ° Peel Test) as it may be ^{390 gf / cm 2 ~ 770gf /} cm 2 as measured, preferably It may be ^{450 gf / cm 2 ~ 750gf /} cm 2, more preferably from ^{500 gf / cm 2 ~ 740gf /} cm 2, days.

The composite sheet of the present invention has a peel strength per hole of 50 to 1,500 gf / hole, preferably 250 to 1,000 gf / cm < 2 > when measured by a 90 degree peel test, according to JIS C 6741 standard. / Hole, more preferably 350 to 950 gf / hole.

The electromagnetic shielding and heat-radiation composite sheet of the present invention can be used as electromagnetic shielding and heat dissipation parts of electronic equipment, and is preferably used as a digitizer, a smart phone, a tablet personal computer (PC) , A portable multimedia player (PMP), or a wearable electronic device such as a VR (Virtual Reality) or a smart watch.

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the scope of the present invention is not limited to the examples illustrated by the following examples.

[Example]

Preparation Example 1-1: Preparation of second electromagnetic wave shielding layer

265.2 parts by weight of a carboxylate nitrile elastomer (weight average molecular weight: 235,500 to 236,500) as a polymeric binder, 100 parts by weight of a silane coupling agent (manufactured by US D Co., Ltd.) per 100 parts by weight of bisphenol A epoxy resin as a thermosetting epoxy resin 2.05 parts by weight of a fluorine-based surfactant (trade name of FC series surfactant manufactured by M Company, USA), 978 parts by weight of an Fe-Si-Al sandstock powder having an average particle size of 42 to 44 μm, , 9.7 parts by weight of 4,4'-diaminodiphenlysulfone (4,4'-diaminodiphenlysulfone), and 10.5 parts by weight of a moisture-proofing agent (Japan S, KP 392) were added to methyl ethyl ketone as an organic solvent Next, the viscosity was adjusted to 1,050 to 1,080 cps and the solid content was adjusted to 53% by weight, and the resulting mixture was applied to a mold release substrate and then aged at 60 DEG C for 24 hours to prepare a semi-cured metal sheet.

Preparation Examples 1-2 to 1-3 and Comparative Preparation Examples 1-1 to 1-2

A metal sheet as a second electromagnetic wave shielding layer was prepared in the same manner as in Preparation Example 1-1, except that a metal sheet having the composition shown in Table 1 was prepared.

division
(Parts by weight) Preparation Example
1-1 Preparation Example
1-2 Preparation Example
1-3 Example of comparison preparation
1-1 Example of comparison preparation
1-2 Thermosetting epoxy resin 100 100 100 100 100 Rubber binder 265.2 300 200 120 265.2 Silane coupling agent 8.5 6.0 8.5 8.5 8.5 Fluorine
Surfactants 2.05 1.87 1.98 2.05 2.05 Soft magnetic powder 978 978 1,290 978 978 Hardener 9.7 9.7 8.6 9.7 9.7 Humidifier 10.5 10.5 13.0 10.5 10.5

Preparation Example 2-1: Preparation of Adhesive

Based on 100 parts by weight of a thermosetting epoxy resin containing bisphenol A epoxy resin (K Chemicals, trade name YD series resin) and novolak epoxy resin (KODO CHEMICAL, YDCN series resin) 1: 0.25 weight ratio, (3M, trade name: FC series surfactant), 0.15 part by weight of a silane coupling agent (Dow Corning, trade name Z6106), 4,4'-diamino di A mixture of 15 parts by weight of phenylsulfone, 3.2 parts by weight of a curing accelerator (manufactured by Shikoku), 5.2 parts by weight of a moisture-proofing agent (Japan S Company, KP series) and 42 parts by weight of a flame retardant (OP series of Swiss C Company) Ethyl ketone and stirred to prepare an adhesive.

Preparative Examples 2-2 to 2-3 and Comparative Preparative Examples 2-1 to 2-2

An adhesive having the composition shown in Table 2 below was prepared in the same manner as in Preparation Example 2-1 to prepare Preparations 2-2 to 2-3 and Comparative Preparations 2-1 to 2-2 Respectively.

division
(Parts by weight) Preparation Example 2-1 Preparation Example 2-2 Preparation Example 2-3 Comparative Preparation Example 2-1 Comparative Preparation Example 2-2 Thermosetting resin Bisphenol A epoxy resin and
Novolac epoxy resin
Mixed resin 1: 0.25
Weight ratio 1: 0.25
Weight ratio Bisphenol A epoxy resin
Exclusive 1: 0.25
Weight ratio 1: 0.25
Weight ratio Total (parts by weight) 100 100 100 100 100 Rubber binder 65 78 65 10 120 Silane coupling agent 1.7 3.9 1.7 1.7 1.7 Fluoric surfactant 0.15 0.35 0.15 0.15 0.15 Hardener 15 9 15 15 15 Hardening accelerator 3.2 1.6 3.2 3.2 3.2 Flame retardant 42 38 42 42 42 Humidifier 5.2 2.7 5.2 5.2 5.2

Preparation Example 3-1: Preparation of Graphite Sheet Having Through Hole

A plurality of circular through holes 11 were formed in a graphite sheet (T company, TGS15) having an average thickness of 17 탆 (see a schematic view of Fig. 4A).

The perforated hole 1 had an average diameter of 3 mm. The major axis distance between the centers of the through holes was 10 mm. The minor axis distance was 12 mm. The total area of the through holes was the entire 3.9 to 4.1% of the area, and the deformation degree of the through-hole was 1.256 based on the following equation (1).

[Equation 1]

Deformation degree = (inside width of shape / circumference length of shape) ^1/2 .

Preparation Example 3-2 ~ Preparation Example 3-9 and Comparative Preparation Example 3-1 ~ Comparative Preparation Example 3-2

Graphite sheets each having a through-hole having a cross-sectional shape as shown in Table 3 below were prepared on the same graphite sheet as the graphite sheet of Preparation Example 3-1, and the characteristics of these graphite sheets are shown in Table 3 below.

In Table 3, through holes are formed by adjusting the number and spacing of the through holes so as to satisfy the entire area of the through holes.

division Through hole cross-sectional shape Heterogeneity Through hole center
Interspacing
(Long axis direction) Through hole center
Interspacing
(Short axis direction) The total area of the top of the seat
Overall area of through hole Preparation Example 3-1 circle
(Diameter 3 mm) 0.866 10 mm 12 mm 4.0% Preparation Example 3-2 circle 0.866 8 mm 12 mm 5.1% Preparation Example 3-3 circle 0.866 6 mm 12 mm 7.5% Preparation Example 3-4 circle 0.866 6 mm 10.5 mm 9.4% Preparation Example 3-5 + Type
(Width 1 mm) 0.678 13 mm 13 mm 5.2% Preparation Example 3-6 + Type
(Width 1 mm) 0.678 11 mm 13 mm 6.5% Preparation Example 3-7 + Type
(Width 1.5 mm) 0.812 13 mm 13 mm 7.4% Preparation Example 3-8 + Type
(Width 1.5 mm) 0.812 11 mm 13 mm 9.3% Preparation Example 3-9 ┏ type
(Width 1 mm) 0.678 13 13 5.2% Preparation Example 3-10 ┏ type
(Width 1 mm) 0.678 11 13 6.5% Preparation Example 3-11 ┏ type
(Width 1.5 mm) 0.812 13 13 7.4% Preparation Example 3-12 ┏ type
(Width 1.5 mm) 0.812 11 11 9.3% Comparative Preparation Example 3-1 circle
(Diameter 9mm) 1.500 10 mm 12 mm 14.8% Comparative preparation example 3-2 circle
(Diameter 0.94 mm) 0.485 10 mm 12 mm 3.3%

Comparative Preparation Example 3-3

A graphite sheet without a through hole (Preparative Example 3-1) (Taiwan T Company, TGS Series product) itself was prepared in Comparative Preparation Example 3-1.

Example 1: Production of integral composite sheet

The adhesive prepared in Preparation Example 2-1 was coated on one surface of a copper foil (first electromagnetic wave shielding layer), and then semi-cured to form an adhesive layer.

The graphite sheet of Preparation Example 3-1 and the second electromagnetic wave shielding layer of Preparation Example 1-1 were bonded and laminated, and then a graphite sheet was laminated on the adhesive layer.

Next, a hot press equipment was put into a sheet laminated with the first electromagnetic wave shielding layer-adhesive layer-thermal diffusion layer-second electromagnetic wave shielding layer.

Next, the hot press was heated from 70 ° C to 150 ° C at a rate of 4 ° C / minute, and thermocompression was performed for 60 minutes under the conditions of 150 ° C and 50 kgf / cm 2 pressure.

Next, after cooling at a rate of 4.5 deg. C / min up to 60 deg. C, the thermocompression-bonded sheet was taken out from the hot press and adhered to the through hole of the thermal diffusion layer as shown in Fig. 1 and the adhesive component derived from the second electromagnetic wave shielding layer Layered electromagnetic wave shielding and heat-radiating composite sheet.

The thickness of the first electromagnetic wave shielding layer 40 was 12 占 퐉, the thickness of the adhesive layer 30 was 5 占 퐉, the thickness of the thermal diffusion layer 10 was 17 占 퐉, The electromagnetic wave shielding layer 30 was 50 m.

Examples 2 to 13

In the same manner as in Example 1, the composite composite sheets of the combinations as shown in Table 4 below were respectively prepared and Examples 2 to 12 were respectively conducted.

Comparative Example 1

The adhesive prepared in Preparation Example 2-1 was coated on one surface of a copper foil (first electromagnetic wave shielding layer), and then semi-cured to form a first adhesive layer.

Next, after the graphite sheet of Comparative Preparation Example 3-1 was laminated on the other surface of the adhesive layer, the adhesive of Preparation Example 2-1 was applied to form a second adhesive layer.

Next, after the second electromagnetic wave shielding layer of Preparation Example 1-1 was laminated on the other surface of the second heat-insulating adhesive layer, a 5-layer type sheet was hot-pressed.

Next, the hot press was heated from 70 ° C to 150 ° C at a rate of 4 ° C / minute, and thermocompression was performed for 60 minutes under the conditions of 150 and 50 kgf / cm 2 pressure.

Next, after cooling at a rate of 4.5 deg. C / minute to 60 deg. C, the thermocompressed sheet was taken out from the hot press to prepare a composite sheet.

The total thickness of the composite sheet thus produced was 90 탆, the thickness of the first electromagnetic wave shielding layer was 12 탆, the first adhesive layer was 4.9 탆, the thermal diffusion layer was 17 탆, the second adhesive layer was 5.2 탆, Was 50.5 mu m.

Comparative Examples 2 to 7

In the same manner as in Example 1, the composite composite sheets of the combinations as shown in Table 5 were prepared, and Comparative Examples 2 to 7 were respectively conducted.

Comparative Example 8

An integral composite sheet was prepared in the same manner as in Example 1, except that the thermocompression bonding was performed for 30 minutes under the conditions of 150 ° C and 50 kgf / cm 2 pressure.

Comparative Example 9

An integral composite sheet was prepared in the same manner as in Example 1, except that the thermocompression bonding was performed for 60 minutes under the conditions of 130 ° C and 50 kgf / cm 2 pressure.

Comparative Example 10

An integral composite sheet was prepared in the same manner as in Example 1, except that the thermocompression bonding was performed at 150 DEG C and 70 kgf / cm < 2 > pressure for 60 minutes.

division The first electromagnetic wave
Shielding layer Adhesive layer Graphite
Sheet layer The second electromagnetic wave
Shielding layer Interlayer thickness (탆) ⁽¹⁾ Example 1 Copper foil Preparation Example
2-1 Preparation Example
3-1 Preparation Example
1-1 12/5/17/50 Example 2 Copper foil Preparation Example
2-1 Preparation Example
3-1 Preparation Example
1-2 12/5/17/50 Example 3 Copper foil Preparation Example
2-1 Preparation Example
3-1 Preparation Example
1-3 12/5/17/50 Example 4 Copper foil Preparation Example
2-2 Preparation Example
3-1 Preparation Example
1-1 12/5/17/50 Example 5 Copper foil Preparation Example
2-3 Preparation Example
3-1 Preparation Example
1-1 12/5/17/50 Example 6 Copper foil Preparation Example
2-1 Preparation Example
3-1 Preparation Example
1-1 15/8/25/65 Example 7 Copper foil Preparation Example
2-1 Preparation Example
3-2 Preparation Example
1-1 12/5/17/50 Example 8 Copper foil Preparation Example
2-1 Preparation Example
3-3 Preparation Example
1-1 12/5/17/50 Example 9 Copper foil Preparation Example
2-1 Preparation Example
3-4 Preparation Example
1-1 12/5/17/50 Example 10 Copper foil Preparation Example
2-1 Preparation Example
3-5 Preparation Example
1-1 12/5/17/50 Example 11 Copper foil Preparation Example
2-1 Preparation Example
3-6 Preparation Example
1-1 12/5/17/50 Example 12 Copper foil Preparation Example
2-1 Preparation Example
3-7 Preparation Example
1-1 12/5/17/50 Example 13 Copper foil Preparation Example
2-1 Preparation Example
3-8 Preparation Example
1-1 12/5/17/50 Example 14 Copper foil Preparation Example
2-1 Preparation Example
3-9 Preparation Example
1-1 12/5/17/50 Example 15 Copper foil Preparation Example
2-1 Preparation Example
3-10 Preparation Example
1-1 12/5/17/50 Example 16 Copper foil Preparation Example
2-1 Preparation Example
3-11 Preparation Example
1-1 12/5/17/50 Example 17 Copper foil Preparation Example
2-1 Preparation Example
3-12 Preparation Example
1-1 12/5/17/50 (1) The order of interlayer thickness is in the order of the first electromagnetic wave shielding layer, the adhesive layer, the graphite sheet layer, and the second electromagnetic wave shielding layer.

division The first electromagnetic wave
Shielding layer Adhesive layer Graphite
Sheet layer The second electromagnetic wave
Shielding layer Interlayer thickness (탆) ⁽¹⁾ Comparative Example 1 Copper foil Preparation Example
2-1 Example of comparison preparation
3-1 Preparation Example
1-1 12/5/17/50 Comparative Example 2 Copper foil Preparation Example
2-1 Example of comparison preparation
3-2 Preparation Example
1-1 12/5/17/50 Comparative Example 3 Copper foil Preparation Example
2-1 Example of comparison preparation
3-3 Preparation Example
1-1 12/5/17/50 Comparative Example 4 Copper foil Preparation Example
2-1 Preparation Example
3-1 Example of comparison preparation
1-1 12/5/17/50 Comparative Example 5 Copper foil Preparation Example
2-1 Preparation Example
3-1 Example of comparison preparation
1-2 12/5/17/50 Comparative Example 6 Copper foil Example of comparison preparation
2-1 Preparation Example
3-1 Preparation Example
1-1 12/5/17/50 Comparative Example 7 Copper foil Example of comparison preparation
2-2 Preparation Example
3-1 Preparation Example
1-1 12/5/17/50 Comparative Example 8 Copper foil Example of comparison preparation
2-2 Preparation Example
3-1 Preparation Example
1-1 12/5/17/50 Comparative Example 9 Copper foil Example of comparison preparation
2-2 Preparation Example
3-1 Preparation Example
1-1 12/5/17/50 Comparative Example 10 Copper foil Example of comparison preparation
2-2 Preparation Example
3-1 Preparation Example
1-1 12/5/17/50 (1) The order of interlayer thickness is in the order of the first electromagnetic wave shielding layer, the adhesive layer, the graphite sheet layer, and the second electromagnetic wave shielding layer.

Experimental Example: Measurement of Peel Strength and Thermal Diffusivity

(1) Total heat dissipation layer peel strength (gf / cm ² ) And peel strength per through hole (gf / Hole)

The integrated composite sheet prepared in each of the Examples and Comparative Examples was prepared in accordance with JIS C 6741, and the peel strength of the entire thermal diffusion layer was measured by a 180 ° peel test (180 ° peel test) Are shown in Table 6 below.

Further, the peel strength per through hole was measured by performing 90 占 peel test (90 占 Peel Test).

(2) Measurement of thermal diffusivity

The integrated composite sheet produced in each of the Examples and Comparative Examples was cut into a size of 10 mm x 10 mm (width, length), and a double-sided tape was attached to one surface of the copper foil (Cu).

Next, the prepared sample is attached onto the heating block and the temperature of the heating block is raised to 80 ° C (the temperature is raised to 80 ° C, which is the temperature of the AP chip in the Smart Phone).

Next, the heating block was sealed in a box and stabilized for 10 minutes. Then, the temperature was measured using an IR camera to determine the highest temperature (hot spot) and the lowest temperature (cold spot) of the composite sheet , And the temperature difference between these was measured to determine the thermal diffusivity of the composite sheet. At this time, the smaller the difference between the two temperatures is, the better the heat radiation performance is.

division Total peel strength
(gf / cm ²⁾ Perforated hall
Peel strength
(gf / hole) Hot spot
(° C) Cold spot
(° C) ΔT
(Hot spot - Cold spot) Example 1 672 503 78.59 56.77 21.82 Example 2 663 489 78.84 57.35 21.49 Example 3 698 507 78.88 56.96 21.92 Example 4 659 482 78.45 56.67 21.78 Example 5 645 473 79.22 57.19 22.03 Example 6 675 496 77.65 56.83 20.82 Example 7 723 504 79.15 56.91 22.24 Example 8 759 503 79.18 56.21 22.97 Example 9 765 506 79.28 56.17 23.11 Example 10 695 832 79.19 56.49 22.70 Example 11 703 828 79.24 56.42 22.82 Example 12 712 830 79.35 56.48 22.87 Example 13 720 832 79.32 56.38 22.94 Example 14 700 825 79.17 56.43 22.74 Example 15 705 830 79.21 56.45 22.76 Example 16 715 833 79.35 56.46 22.89 Example 17 722 835 79.37 56.41 22.96 Comparative Example 1 1,052 1,325 82.04 57.02 25.02 Comparative Example 2 439 148 78.45 56.84 21.61 Comparative Example 3 337 - 78.74 57.88 20.86 Comparative Example 4 662 511 79.12 56.55 22.57 Comparative Example 5 681 497 79.14 56.86 22.28 Comparative Example 6 636 402 79.24 56.36 22.88 Comparative Example 7 429 382 79.22 56.19 22.46 Comparative Example 8 385 168 79.68 55.16 24.52 Comparative Example 9 364 157 79.94 55.21 24.73 Comparative Example 10 662 495 80.21 56.24 23.97

In the case of Examples 1 to 17, the total peel strength was not less than 600 gf / cm ² , the peel strength per pass hole was not less than 400 gf / hole, And the difference of cold spot was less than 23.20.

More specifically, through comparison of Examples 1 to 3, it was found that as the rubber binder in the second electromagnetic wave shielding layer increases, the peel strength is somewhat reduced, but the thermal diffusivity tends to increase, and the amount of rubber binder decreases , The peel strength increased and the thermal diffusivity tended to decrease.

In comparison between Example 1 and Example 5, Example 1 using two types of thermosetting resins mixed with one type (Example 5) as an adhesive thermosetting resin showed excellent adhesiveness, The intensity showed a tendency to be somewhat high.

In Examples 6 to 17, the tendency to influence the peel strength and the thermal diffusion performance was confirmed by the cross-sectional shape of the through holes, the spacing between the through holes, and the total area of the through holes.

On the contrary, in the case of the integral composite sheet (Comparative Example 1) made of the graphite sheet of Comparative Preparation Example 3-1 equipped with the through hole having the profile of 1.5 and the total area of the through hole of 14.8%, the peel strength But the hot spot temperature was high and the thermal diffusivity was low.

The integrated composite sheet of Comparative Example 2 in which the graphite sheet of Comparative Preparative Example 3-2 was introduced with less than 0.500 degree of release and the composite composite sheet of Comparative Example 3 in which the graphite sheet of Comparative Preparative Example 3-3 without through holes was introduced , The thermal diffusivity was very good, but the peel strength per through hole was low.

Comparative Example 4 in which a metal sheet (second electromagnetic wave shielding layer) prepared by using a rubber binder of less than 160 parts by weight was introduced, and Comparative Example 4 in which a metal sheet prepared by using 1,500 parts by weight or more of soft magnetic powder was introduced In the case of Example 5, there was a problem that the bonding strength between the second electromagnetic wave shielding layer and the thermal diffusion layer was partly peeled off when the composite sheet was bent arbitrarily. However, the flexibility of the metal sheet itself was poor It seems to be because of

In Comparative Example 6 using the adhesive of Comparative Preparation Example 2-1, which was produced by using 10 parts by weight of the rubber binder in an amount of less than 25 parts by weight, the peel strength and the heat diffusing ability were excellent as a whole, Similarly, when the composite sheet is arbitrarily bent, the first electromagnetic wave shielding layer and the region between the thermal diffusion layers are partially peeled off.

In the case of Comparative Example 7 using the adhesive of Comparative Preparation Example 2-2 prepared by using 120 parts by weight of the rubber binder in an amount exceeding 100 parts by weight, the peeling strength was lowered, because the amount of the other composition in the adhesive layer was decreased It is judged that the adhesiveness of the adhesive layer is decreased.

In the case of Comparative Example 8 in which the hot press was performed for 30 minutes at the time of producing the composite sheet, the peel strength per through hole was low and the thermal diffusivity was also lowered, It is judged that the component does not flow out, the unfilled portion of the adhesive component exists in the through hole, the peeling strength is lowered, and the thermal diffusion is disturbed by the non-filled region.

As compared with Comparative Example 8 in which the hot press was carried out at 130 占 폚 at a temperature of less than 145 占 폚, as in Comparative Example 8, the adhesive component did not sufficiently leak out from the second electromagnetic wave shielding layer, , The peel strength and the thermal diffusibility were deteriorated.

In the case of Comparative Example 10 in which the hot press was performed at a pressure of 70 kgf / cm 2, the bonding strength was excellent, but the thermal diffusivity was somewhat lowered as compared with Example 1, As well.

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.

1, 2, 3, 4: Through hole 10: Graphite sheet layer provided with through holes
20: adhesive layer or adhesive 20 ': adhesive derived from the second electromagnetic wave shielding layer
30: second electromagnetic wave shielding layer 40: first electromagnetic wave shielding layer
100: Electromagnetic wave shielding and heat radiation composite sheet

Claims (14)

A first electromagnetic wave shielding layer; An adhesive layer; Thermal diffusion layer; And a second electromagnetic wave shielding layer; and a graphite sheet constituting a thermal diffusion layer of the electromagnetic wave shielding and heat-
A plurality of through-holes having a cross-sectional shape having a distribution curve satisfying the following equation (1)
Wherein the second electromagnetic wave shielding layer comprises a cured sheet formed of a resin containing an electromagnetic shielding component and the inside of the graphite sheet through hole is filled with a resin derived from the second electromagnetic wave shielding layer. A graphite sheet for an excellent electromagnetic wave shielding and heat radiation composite sheet;
[Equation 1]
0.500 ≤
In the above equation (1), the mold-outline is (inner width of the shape / circumference length of the shape) ^1/2 .
The graphite sheet for electromagnetic shielding and heat-radiating composite sheet according to claim 1, wherein the through hole area is 2% to 30% of the total area of the top or bottom surface of the graphite sheet.
The electromagnetic wave shielding and heat dissipating device according to claim 1, wherein the cross-sectional shape includes at least one selected from a circle, an ellipse, a +, a x, a ┠, Graphite sheet for composite sheet.
4. The method of claim 3, wherein the circular shape is circular with an average diameter of 0.5 mm to 8 mm,
Wherein the + type has a diameter ratio of the inscribed circle and the circumscribed circle of 1: 2 to 10. The graphite sheet for electromagnetic wave shielding and heat radiation composite sheet excellent in interlayer adhesion.
A first electromagnetic wave shielding layer; An adhesive layer; A thermal diffusion layer comprising a graphite sheet of any one of claims 1 to 4; And a second electromagnetic wave shielding layer are stacked in this order,
Wherein the second electromagnetic wave shielding layer comprises a cured sheet formed of a resin containing an electromagnetic wave shielding component,
And the inside of the graphite sheet through-hole is filled with the resin derived from the second electromagnetic wave shielding layer.
6. The electronic device according to claim 5, wherein a resin derived from the second electromagnetic wave shielding layer and an adhesive derived from the adhesive layer are filled,
And an adhesive layer is not provided between the thermal diffusion layer and the second electromagnetic wave shielding layer.
The electromagnetic shielding and heat-radiating composite sheet according to claim 5, wherein the resin filled in the through-hole does not contain a soft magnetic powder.
The method of claim 5, wherein the first electromagnetic wave shielding layer is a copper foil or an aluminum foil,
Wherein the adhesive layer comprises a thermosetting epoxy resin, a rubber binder, a silane coupling agent, a fluorine surfactant, a curing agent, a curing accelerator, a flame retardant,
Wherein the second electromagnetic wave shielding layer is a cured product of a mixed resin including a thermosetting epoxy resin, a rubber binder, a silane coupling agent, a fluorine surfactant, a soft magnetic powder, a hardener, and a moisture-proofing agent.
6. The electromagnetic wave shielding film according to claim 5, wherein the first electromagnetic wave shielding layer has an average thickness of 5 mu m to 70 mu m, the adhesive layer has an average thickness of 2 mu m to 25 mu m, the thermal diffusion layer has an average thickness of 10 mu m to 40 mu m, Wherein the electromagnetic shielding and heat-radiating composite sheet has a thickness of 30 to 300 mu m.
6. The method according to claim 5, wherein, in accordance with JIS C 6741, the peel strength per hole in the thermal diffusion layer is 50 to 1,500 gf /
Wherein the peel strength of the thermal diffusion layer with respect to the second electromagnetic wave shielding layer is 390 gf / cm ² to 770 gf / cm ² when measured according to JIS C 6741 standard.
A first step of putting a laminate in which a first electromagnetic wave shielding layer, an adhesive layer, a thermal diffusion layer including a graphite sheet of any one of claims 1 to 4 and a second electromagnetic wave shielding layer are laminated, into a hot press equipment;
A second step of heating and pressing the laminate under a pressure of 145 to 160 占 폚 and 45 to 60 kgf / cm2 to perform a hot press process; And
And cooling the hot press and then separating the composite sheet integrated from the hot press,
The resin included in the second electromagnetic wave shielding layer in the first step is not filled in the through holes of the graphite,
Wherein the resin contained in the second electromagnetic wave shielding layer is filled into the inside of the graphite sheet through-hole when performing the two-step hot pressing process.
A coverlay film comprising the composite sheet of claim 5.
A flexible circuit board comprising the composite sheet of claim 5.
A portable electronic device comprising the composite sheet of claim 5.

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