KR20190003899A - Composite sheet with EMI shield and heat radiation and Manufacturing method thereof - Google Patents

Abstract

The present invention relates to a composite sheet for EMI shield and heat radiation and a manufacturing method thereof. A pressure sensitive adhesive layer having excellent horizontal thermoconductivity, durability against heat shock, and electromagnetic shielding property as well as excellent adhesion at high temperature and at room temperature is introduced to maintain the inter-sheet adhesion reliability even in a rework process for applying high temperature heat, and can perform rework without discarding a composite sheet. The composite sheet includes an acrylic polymer; and a high-temperature cohesive strengthening resin.

Description

 TECHNICAL FIELD [0001] The present invention relates to an EMI shielding and heat radiation composite sheet,

The present invention relates to an electromagnetic wave shielding and heat-radiation composite sheet, and more particularly, to a thin electromagnetic shielding and heat-radiation composite sheet having excellent horizontal heat conductivity, durability against thermal shock and electromagnetic wave shielding, and a manufacturing method thereof.

[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 graphite 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.

On the other hand, the heat-radiating sheet and the electromagnetic-wave shielding sheet are generally used by being attached to a substrate (apparatus, substrate, component, etc.) requiring electromagnetic shielding and heat dissipation. To the substrate.

In this case, a reheating process may occur in which the heat-radiating sheet and the electromagnetic shielding sheet are removed again due to erroneous adhesion. For easy rework process, generally, the adhesive material uses heat-deformable materials and is easily removed by heat at a high temperature .

However, the electromagnetic shielding and heat-radiating composite sheet is liable to be wrinkled, bent, cracked, or the like due to high temperature heat applied in the rework process, resulting in reduced reliability and difficulty in reusing.

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

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to provide a thin electromagnetic shielding and heat-radiating composite sheet excellent in horizontal thermal conductivity, durability against thermal shock, and electromagnetic shielding.

The present invention also provides a pressure sensitive adhesive layer having excellent adhesiveness not only at room temperature but also at high temperature, and is capable of maintaining the inter-sheet adhesion reliability even in the rewiring process in which high temperature heat is applied, And a heat-radiating composite sheet.

In order to solve the above-described problems, the electromagnetic wave shielding and heat-radiation composite sheet of the present invention is characterized in that the electromagnetic wave shielding and heat radiation composite sheet of the present invention is formed by sequentially stacking an electromagnetic wave shielding layer, a first adhesive layer, a graphite layer having a plurality of through holes, a second adhesive layer, Wherein the pressure-sensitive adhesive layer comprises an acrylic polymer having a glass transition temperature of -65 DEG C to -25 DEG C and a high-temperature cohesive strength resin having a softening point of 70 DEG C to 147 DEG C and a weight average molecular weight of 100 to 5,000, The layer can satisfy Equation 1 below.

[Equation 1]

(d2 + d3)? d1? 4 (d2 + d3)

D1 is the average thickness of the graphite layer, d2 is the average thickness of the first adhesive layer, and d3 is the average thickness of the second adhesive layer.

As a preferred embodiment of the present invention, the first adhesive layer and the second adhesive layer can satisfy the following equation (2).

[Equation 2]

d2? d3

d2 is the average thickness of the first adhesive layer, and d3 is the average thickness of the second adhesive layer.

In a preferred embodiment of the present invention, the inside of the through hole of the graphite layer may be filled with an adhesive derived from the first adhesive layer and the second adhesive layer.

In one preferred embodiment of the present invention, the acrylic polymer may have a glass transition temperature of -54 ° C to -36 ° C, and the high-temperature adhesive resin may have a softening point of 80 ° C to 145 ° C and a weight average molecular weight of 500 to 3,000 .

In one preferred embodiment of the present invention, the acrylic polymer may include a compound represented by the following general formula (1).

[Chemical Formula 1]

In Formula 1, R ₁ , R ₂ and R ₃ are each independently -H, -OH, a C 1 to C 10 alkyl group or a C 1 to C 5 alkoxy group, and n has a weight average molecular weight of 200,000 to 150,000 It is rational number.

As one preferred embodiment of the present invention, the high-temperature adhesive and reinforced resin may include a modified reaction compound by reacting a compound represented by the following formula (2) with at least one selected from formaldehyde and phenol.

(2)

In Formula 2, R ₄ , R ₅ , R ₆ , R ₇ and R ₈ each independently may be -H, a C1-C10 alkyl group, an alcohol group or a carboxyl group.

In one preferred embodiment of the present invention, the pressure-sensitive adhesive layer may contain 15 to 35 parts by weight of a high-temperature cohesive strengthening resin per 100 parts by weight of the acrylic polymer.

In one preferred embodiment of the present invention, the pressure-sensitive adhesive layer may further comprise a curing agent, and the curing agent may include at least one selected from an epoxy curing agent and an acrylic curing agent.

In one preferred embodiment of the present invention, the pressure-sensitive adhesive layer may include 0.13 to 0.25 parts by weight of the curing agent relative to 100 parts by weight of the acrylic polymer.

In one preferred embodiment of the present invention, the pressure-sensitive adhesive layer may further include a silane coupling agent, and the silane coupling agent may include 0.0001 to 0.002 parts by weight based on 100 parts by weight of the acrylic polymer.

As a preferred embodiment of the present invention, the pressure-sensitive adhesive layer of the present invention has a pressure-sensitive adhesive layer of 0.70 to 1.0 kgf / inch at a temperature of 25 캜 and a pressure of 0.7 To 1.2 kgf / inch.

Meanwhile, the coverlay film of the present invention may include the aforementioned electromagnetic wave shielding and heat-radiation composite sheet.

In addition, the flexible circuit board of the present invention may include the aforementioned electromagnetic wave shielding and heat-radiation composite sheet.

Further, the portable electronic device of the present invention may include the aforementioned electromagnetic wave shielding and heat-radiation composite sheet.

Furthermore, the method for manufacturing an electromagnetic shielding and heat-radiating composite sheet of the present invention is a method for manufacturing an electromagnetic shielding and heat-radiating composite sheet, which comprises an electromagnetic wave shielding layer, a first adhesive layer, a graphite layer having a plurality of through holes, a second adhesive layer, Two steps of heating and pressing the laminate at 145 DEG C to 160 DEG C and 45 to 60 kgf / cm < 2 > pressure for 50 minutes to 70 minutes, cooling the hot press, Wherein the pressure-sensitive adhesive layer has an acrylic polymer having a glass transition temperature of -65 ° C to -25 ° C and a softening point of 70 ° C to 147 ° C and a weight average molecular weight of 100 to 5,000 And a high-temperature cohesion-strengthening resin, wherein the graphite layer can satisfy the following equation (1).

[Equation 1]

(d2 + d3)? d1? 4 (d2 + d3)

D1 is the average thickness of the graphite layer, d2 is the average thickness of the first adhesive layer, and d3 is the average thickness of the second adhesive layer.

As a preferred embodiment of the present invention, the first adhesive layer and the second adhesive layer of the method for producing an electromagnetic shielding and heat radiation composite sheet of the present invention can satisfy the following equation (2).

[Equation 2]

d2? d3

d2 is the average thickness of the first adhesive layer, and d3 is the average thickness of the second adhesive layer.

The electromagnetic wave shielding and heat radiation composite sheet of the present invention is excellent in horizontal thermal conductivity, durability against thermal shock, and electromagnetic wave shielding.

Further, the electromagnetic wave shielding and heat radiation composite sheet of the present invention introduces a pressure-sensitive adhesive layer having excellent adhesiveness not only at room temperature but also at high temperature, and maintains the inter-sheet adhesion reliability even during the reheating step in which high temperature heat is applied, Re-workability is possible.

1 is a schematic cross-sectional view of an electromagnetic wave shielding and heat-radiation composite sheet to which the pressure-sensitive adhesive of the present invention is applied, according to a preferred embodiment of the present invention.
2 is a schematic view of a preferred embodiment of a graphite layer having a plurality of through holes constituting the electromagnetic shielding and heat-radiation composite sheet of the present invention.
Figs. 3 (a) and 3 (b) are schematic views of a form in which an adhesive component derived from the first adhesive layer and / or the second adhesive layer is filled in the through hole of the graphite layer.
4 is a schematic view of a graphite sheet used in the electromagnetic shielding and heat-radiating composite sheet of the present invention, as a preferred embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art to which the present invention pertains. The present invention may be embodied in many different forms and is not limited to the embodiments described herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same reference numerals are assigned to the same or similar components throughout the specification.

The room temperature in the present invention may be generally 10 to 40 占 폚, preferably 15 to 35 占 폚, and more preferably 20 to 30 占 폚. The high temperature in the present invention may be a temperature of 70 to 100 ° C, preferably 75 to 95 ° C, more preferably 80 to 90 ° C.

The electromagnetic wave shielding and heat radiation composite sheet of the present invention will be described in detail as follows.

1, the electromagnetic shielding and heat-radiating composite sheet of the present invention comprises a graphite layer 20 having an electromagnetic wave shielding layer 20, a first adhesive layer 30, and a plurality of through holes 1, 2, The first adhesive layer 10, the second adhesive layer 40, the support layer 50, and the pressure-sensitive adhesive layer 60 may be sequentially laminated.

Generally, a graphite sheet having a passivation film on both sides or one side thereof is used in producing a heat radiation film using a graphite sheet. However, the graphite layer (10) of the electromagnetic shielding and heat radiation composite sheet of the present invention has passivation A film is not provided and an adhesive component derived from the first adhesive layer 30 and / or the second adhesive layer 40 may be filled in the through-hole of the graphite layer.

Since the planar size of the graphite layer is smaller than the planar size of the electromagnetic wave shielding layer 20 and the support layer 50, the planar size of the electromagnetic wave shielding / And there is no adhesive component originating from the first adhesive layer 30 and / or the second adhesive layer 40, it is preferable that the thickness of the graphite layer as viewed from the side of the electromagnetic shielding and heat radiation composite sheet There is a spacing space between the outside of the graphite layer and the electromagnetic wave shielding layer and the support layer.

2 and 3, the graphite layer 10 has a plurality of through holes 1, 2, 3, and 4 provided therein, and the through holes, the electromagnetic wave shielding layer, The electromagnetic wave shielding layer 20, the graphite layer 10, and the support layer 50 are combined and integrated by being filled with the adhesive component originating from the first adhesive layer and / or the second adhesive layer in the spacing space between the layers. To be more specific, the first adhesive layer and / or the second adhesive layer are semi-cured. When layers are stacked, pressure is applied by a press, or heat and pressure are applied by a hot press, a part of the adhesive component in the first adhesive layer and / or the second adhesive layer is melted and filled in the through- (25, 25 ') (see Figs. 3 (a) to 3 (b)).

Each layer constituting the electromagnetic shielding and heat-radiation composite sheet of the present invention will be described more specifically.

[Electromagnetic wave shielding layer]

First, the electromagnetic wave shielding layer 20 is a material having a heat radiation and an electromagnetic shielding function, and a metal foil commonly used in the art can be used. Preferably, a copper foil, an aluminum foil or a metal sheet can be used.

It is preferable that the electromagnetic wave shielding layer 20 has an average thickness of 5 탆 to 70 탆, preferably 8 to 40 탆, more preferably 10 to 35 탆. If the average thickness of the electromagnetic wave shielding layer is less than 5 탆, There may be a problem that occurrence and tear phenomenon occurs. When it exceeds 70 탆, it may be difficult to form a thin film and the product flexibility may be lowered, so that it is preferable to have an average thickness within the above range.

[ Adhesive layer ]

The first adhesive layer 30 serves to bond between the electromagnetic wave shielding layer 20 and the graphite layer 10 and has a function of allowing heat transfer from the electromagnetic wave shielding layer 20 to the graphite layer 10 It is preferable to use a heat-resistant heat-insulating adhesive. Preferably, the first adhesive layer (or the heat-dissipating adhesive) includes a thermosetting resin, and a rubber binder, a silane coupling agent, a fluorine-containing surfactant , A curing agent, and a curing accelerator, and may further include at least one selected from a flame retardant, a moisture-proofing agent and a thermally conductive filler, if necessary.

Further, the adhesive component originating from the first adhesive layer 30 is filled in the through hole of the graphite layer 10, thereby improving the peel strength of the graphite layer 10.

The second adhesive layer 40 serves to bond the graphite layer 10 and the support layer 50 and the adhesive component derived from the second adhesive layer 40 is filled in the through hole in the graphite sheet, Thereby improving the peel strength of the graphite sheet.

The second adhesive layer 40 includes a thermosetting resin and further includes a rubber binder, a silane coupling agent, a fluorine surfactant, a curing agent, and a curing accelerator, and if necessary, at least one selected from a flame retardant, a moisture- As shown in FIG.

Among the components of the first adhesive layer 30 and / or the second adhesive layer 40, 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. More preferably, it includes at least one selected from the group consisting of a bisphenol A epoxy resin, a bisphenol F epoxy resin, a novaleak epoxy resin and a halogen-containing epoxy resin can do.

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.

Among the components of the first adhesive layer 30 and / or the second adhesive layer 40, the rubber binder may play a role in imparting resistance to scratching and may be formed of an acrylic rubber, a silicone rubber, a carboxylated nitrile elastomer ) And phenoxy, and preferably one or two or more of acrylic rubber and silicone rubber may be included. Carboxylic elastomer may be used, and it is preferable to use a carboxylnitrile elastomer. It is preferable that the carboxyl-based elastomer 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 securing the heat resistance of the first adhesive layer and / or the second adhesive layer (30, 40). 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, There is a problem that the joint between the electromagnetic wave shielding layer 20 and the graphite layer 10 is partially peeled off when the electromagnetic shielding and heat-radiating composite sheet 30 is bent and / or the second adhesive layer 40 is low in flexibility If used in an amount of more than 100 parts by weight, the amount of other components used in the first adhesive layer 30 and / or the second adhesive layer 40 is relatively reduced, and the first adhesive layer 30 and / There may be a problem that the adhesion of the layer 40 is reduced.

Among the components of the first adhesive layer 30 and / or the second adhesive layer 40, the silane coupling agent plays a role of dispersing the particles and may be a conventional silane coupling agent used in the art, (C 2 to C 5 alkyl) trialkoxysilane, Vinyltri (C 2 to C 5 alkoxy) silane, and aminoethylaminopropylsilane triol. More preferably, at least one of glycidoxypropyltrimethoxysilane, glycidoxypropyltrimethoxysilane, glycidoxypropylethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, And aminoethylaminopropylsilanetriol may be used singly or in combination of two or more. The amount of the silane coupling agent to be used may be 1 to 10 parts by weight, preferably 1 to 5 parts by weight, based on 100 parts by weight of the thermosetting resin. When the amount of the silane coupling agent is less than 1 part by weight, The effect of dispersing the particles may not be seen. If the dispersing agent is used in an amount exceeding 10 parts by weight, there may be a problem that particle aggregation occurs due to the reaction between the coupling agents.

Among the components of the first adhesive layer 30 and / or the second adhesive layer 40, the fluorochemical surfactant has a function of lowering the surface tension to improve the coating property, and it is possible to use a general surfactant used in the art, A fluoroaliphatic polymeric ester may be used. 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.

Examples of the curing agent in the first adhesive layer 30 and / or the second adhesive layer 40 include an amine type hardener, an anhydride type hardener and a phenol type hardener. At least one of amine type hardeners and anhydride type hardeners may be used, and specific examples thereof include 4,4'-diamine 4,4'-diaminodiphenlysulfone can be used 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 first adhesive layer 30 and / or the second adhesive layer 40, the curing accelerator may include at least one of an aromatic amine, an aliphatic amine, and an aromatic tertiary amine, preferably an aromatic amine and an aromatic Tertiary amines, and the like. 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 excess of 5 parts by weight, the adhesive layer may be hardened too quickly.

Among the components of the first adhesive layer 30 and / or the second adhesive layer 40, the flame retardant is used for obtaining a flame retardant effect of the product, and any of those commonly used in the art may be used. Preferably, the flame retardant is a phosphorus- Chlorinated flame retardants and the like can be used alone or in combination of two or more. Specific examples thereof include Clariant EXOLIT OP 935, H42M of Showa Denko Co., Ltd., H32 and H43M of Showa Denko Co., Ltd. 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.

The moisture-proofing agent in the first adhesive layer 30 and / or the second adhesive layer 40 is for adjusting the moisture content in the first adhesive layer 30 and / or the viscosity of the adhesive in the second adhesive layer 40 , And those commonly used in the art can be used. Preferred examples thereof include one or a mixture of two or more selected from aluminum sulfate, latex, silicone emulsion, poly (organosiloxane), hydrophobic polymer emulsion, Can be used. 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 an amount exceeding 10 parts by weight, it may be difficult to control the proper amount of water in the first adhesive layer 30 and / or the second adhesive layer 40 due to overuse. Therefore, .

Meanwhile, the first adhesive layer 30 and / or the second adhesive layer 40 of the present invention may further include a thermally conductive filler and / or a dispersant.

The thermally conductive filler may be one or a mixture of graphite powder, carbon nanotube (CNT), carbon black, carbon fiber, ceramic, and metal powder. Two or more of them may be used in combination. Preferably, graphite powder, ceramics and metal powder may be used alone or in combination of two or more. 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. When the thermally conductive filler is used in excess of 1,100 parts by weight, And the vertical thermal conductivity of the electromagnetic shielding / heat radiation composite sheet can be greatly increased. Therefore, it is preferable to use it within the above range.

When the average particle diameter is less than 3 mu m, the particles may be difficult to disperse. If the average particle diameter exceeds 25 mu m, the thin film coating and the adhesive strength may be deteriorated. Therefore, 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 first adhesive layer 30 and / or the second adhesive layer 40 may be a mixture of the above-mentioned curable resin, rubber binder, silane coupling agent, fluorochemical surfactant, curing agent, curing accelerator, flame retardant, moisture- Can be added to an organic solvent to control the viscosity and solids content of the adhesive. 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 first adhesive layer 30 may have an average thickness of 2 탆 to 25 탆, preferably 3 탆 to 15 탆, more preferably 4 to 8 탆, wherein the average thickness of the first adhesive layer 30 is 2 (Or adhesive force) between the electromagnetic wave shielding layer 20 and the graphite layer 10 may be lowered, and if it is more than 25 m, it is uneconomical and disadvantageous for thinning of the electromagnetic wave shielding and heat radiation composite sheet.

If the average thickness of the second adhesive layer 40 is less than 2 占 퐉, the graphite layer 10 (10 占 퐉) may be used as the second adhesive layer 40. If the second adhesive layer 40 has an average thickness of 2 占 퐉 to 25 占 퐉, preferably 3 占 퐉 to 15 占 퐉, (Or adhesive force) between the support layer 50 and the support layer 50 may be lowered, and if it exceeds 25 μm, it is uneconomical and disadvantageous to the thinness of the electromagnetic wave shielding and heat radiation composite sheet.

[ Graphite layer ]

Next, the graphite layer 10 may be composed of a graphite sheet (or film) having excellent thermal conductivity and provided with a plurality of through holes 1, 2, 3, 4 (see FIG. 2).

And a separate adhesive layer between the support layer 50 and the graphite layer 10 is formed between the electromagnetic wave shielding layer 20 and the support layer 50 disposed below and above the graphite layer 10 through such through holes So that the composite sheet can be made thinner.

Further, a graphite sheet in which a through hole is formed so as to have a deviation degree satisfying the following expression (2) can be used so as to realize excellent horizontal thermal conductivity and high peel strength between the support layer 50 and the graphite layer 10 .

&Quot; (2) "

0.500 ≤ 1 ≤ 1.300, preferably 0.520 ≤

In the formula (2), the stereogram is ^1/2 of the inner width of the shape / the peripheral length of the shape.

In the above formula (2), when the degree of differentiation is less than 0.500, the overall thermal diffusibility is excellent, but the peel strength such as the peel strength per through hole can be low and the peel strength between the support layer and the graphite layer can be low. However, there may be a problem that the vertical thermal conductivity increases.

The cross-sectional shape of the through-hole may be at least one selected from the group consisting of a circle, an ellipse, a +, a x, a ┣, a ┏, the through holes may be formed on the graphite sheet by combining various cross-sectional shapes as shown in Fig. 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.

As a specific example, 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, and more preferably 1 mm to 4 mm. If the average diameter of the through holes is less than 0.5 mm There is a problem that the durability against thermal shock due to the increase in the number of the through holes provided in the graphite layer may be reduced and the filling rate of the adhesive component filled in the through holes may be reduced to reduce the durability against thermal shock When the thickness is more than 8 mm, the thermal diffusing performance in the horizontal direction of the graphite layer decreases, and the shape retention ability of each layer may be decreased during the production of the composite sheet to increase the percentage of defects. May be 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, 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 to secure a horizontal thermal conductivity of the graphite layer, It is advantageous in terms of securing adequate adhesion between the graphite layers and preventing interlayer delamination of the graphite layer itself.

The through hole area of the graphite layer 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, If the through hole area is less than 2%, there is a problem in that the peel strength between the support layer and the graphite layer is low. If it exceeds 30%, the peel strength is excellent, but the vertical thermal conductivity may increase, Therefore, it is preferable to form the through holes so as to have the above-mentioned area ratio.

On the other hand, as shown schematically in FIG. 4, as an example, a plurality of through holes 1 provided in a graphite sheet (or graphite layer) 10 may alternately be arranged.

By providing the through holes so that the graphite sheets are arranged alternately in this manner, when the electromagnetic shielding and heat radiation composite sheet is bent while increasing the flexibility of the electromagnetic wave shielding and heat radiation composite sheet than the electromagnetic wave shielding and heat radiation composite sheet not alternately arranged, Can be prevented from being peeled off from the layer bonded thereto.

To describe the graphite sheet more specifically, when one surface of the graphite sheet is viewed in xy coordinates, a plurality of through holes may be formed in the rows formed in the x axis direction at regular intervals and repeated. In addition, the heat is divided into an odd number column (1 column, 3 columns, 5 columns) and an even number column (2 columns, 4 columns, 6 columns, (Y "axis) of the first through-hole in the even-numbered column may exist between the axis (y 'axis) and the y" axis at the center of the y and y' axes, 'Axis direction.

The distance between the through holes of the graphite sheet may be formed so as to satisfy the following equation (1).

[Equation 1]

d = (0.5 to 1.5) L, preferably d = (0.55 to 1.2) L, more preferably d = (0.6 to 1.0) L

In Equation (1), L is the distance between the center axis of the through hole formed in the x axis direction and the center axis of the neighboring through hole, and d is the distance between the center axis (x axis) of the through hole existing in each of the odd column and the even column.

If the value of d is less than 0.5 L, the horizontal thermal conductivity may be lowered. If the value of d exceeds 1.5 L, the distance between the odd columns and the even-numbered holes is relatively large, There may be a problem that the difference in strength is increased. Therefore, it is preferable to form the through-holes so as to have an interval satisfying the above-mentioned expression (1).

The graphite sheet (or film) constituting the graphite layer may be a general graphite sheet used in the art, 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 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 the rolling roll at a temperature of 2,000 ~ 3,200 ° C, pore removal and density are increased, The maximized graphitized polyimide can be produced.

The thickness of the graphite layer 10 in the electromagnetic shielding and heat-radiating composite sheet of the present invention is preferably formed to have a thickness satisfying the following equation (1).

[Equation 1]

 (d2 + d3)? d1? 4 (d2 + d3), preferably (d2 + d3)? d1? 3.5 (d2 + d3), more preferably d2 + d3) , Still more preferably (d2 + d3)? D1? 2.5 (d2 + d3)

D1 is the average thickness of the graphite layer, d2 is the average thickness of the first adhesive layer, and d3 is the average thickness of the second adhesive layer.

At this time, if d1 is smaller than (d2 + d3), the first and second adhesive layers are entirely too thick as a whole, which is disadvantageous in making the composite sheet thinner and the heat radiation effect may be lowered. If d1 is larger than 4 (d2 + d3), the first and second adhesive layers are relatively thin, so that the adhesive component can not be sufficiently filled in the holes in the graphite layer and the peel strength per hole of the graphite layer is lowered Can be.

It is preferable that the first adhesive layer and the second adhesive layer of the composite sheet satisfy the following equation (2).

[Equation 2]

d2? d3

D2 is the average thickness of the first adhesive layer, and d3 is the average thickness of the second adhesive layer.

It is preferable that the first adhesive layer and the second adhesive layer satisfy Equation 1 and preferably satisfy Equation 2. When the first adhesive layer d2 is thick in the heat radiation direction, If the first adhesive layer is thin, the second adhesive layer must be formed sufficiently thick so as to sufficiently fill the adhesive component in the holes of the graphite layer. Therefore, when the thicknesses of the first adhesive layer and the second adhesive layer are differently formed It is preferable that the second adhesive layer is thicker than the first adhesive layer.

[ Support layer ]

Next, the support layer 50 serves to prevent wrinkling, bending, and breaking of the electromagnetic wave shielding layer 20 and / or the graphite layer 10.

The support layer 50 may include at least one selected from polyimide (PI) resin and heat-resistant PET (polyethylene terephthalate) resin.

The polyimide resin may be a high heat-resistant resin prepared by preparing a polyamic acid derivative by combining an aromatic dianhydride with an aromatic diamine or an aromatic diisocyanate in solution and then dehydrating and cyclizing at a high temperature to imidize it. Therefore, such a polyimide resin is an insoluble and infusible ultra high heat resistant resin and can have properties such as heat oxidation resistance, heat resistance, radiation resistance, low temperature characteristics, and chemical resistance

The thickness of the support layer 50 is not particularly limited. However, considering the thickness of the electromagnetic shielding and heat radiation composite sheet to be produced, the thickness of the support layer 50 is preferably from 9 탆 to 75 탆, more preferably from 15 탆 to 50 탆, If the average thickness of the support layer 50 is less than 9 탆, problems such as wrinkling of the graphite layer may occur. If the average thickness exceeds 75 탆, flexibility may be a problem.

[ Sensitive pressure-sensitive adhesive layer ]

Finally, the pressure-sensitive adhesive layer 60 maintains an excellent adhesive force even at a high temperature, and maintains the reliability of the electromagnetic shielding and heat-radiation composite sheet even in the rework process in which high-temperature heat is applied, The interface separation between the layer 60 and the adhesive layer can be minimized.

The pressure-sensitive adhesive layer 60 may have an average thickness of 5 탆 to 50 탆, preferably 20 탆 to 30 탆. If the average thickness of the pressure-sensitive adhesive layer 60 is less than 5 mu m, there may be a problem of deterioration of the adhesive strength, while if it exceeds 50 mu m, the stability of the pressure-sensitive adhesive may be deteriorated.

The pressure-sensitive adhesive layer of the present invention may comprise an acrylic polymer and a high-temperature cohesive strengthening resin.

Acrylic polymer is a permanent type adhesive component, which is an adhesive component which has high adhesion when peeled off after adhering to an adherend, thereby causing a transition.

The acrylic polymer of the present invention may have a glass transition temperature of -65 ° C to -25 ° C, preferably -54 ° C to -36 ° C, more preferably -50 ° C to -40 ° C.

In addition, the acrylic polymer of the present invention may include a compound represented by the following general formula (1).

[Chemical Formula 1]

In the formula 1, R _1, R _2, R ₃ are each independently -H, -OH, alkoxy may be date of C1 ~ C10 alkyl group or C1 ~ C5 one, and preferably R ₁ is -H or C1 ~ R ₂ may be a C 3 to C 5 alkyl group, R ₃ may be a -H, -OH, or a C 1 to C 2 alkoxy group.

In the general formula (1), n may be a rational number satisfying a weight average molecular weight of 200,000 to 150,000, and preferably a rational number satisfying a weight average molecular weight of 400,000 to 60,000.

The high-temperature cohesive strengthening resin of the present invention may be a terpene phenol-based resin as a resin for increasing the adhesive force to the adhesive component. Also, since the high temperature adhesive and reinforced resin is included in the above-mentioned acrylic polymer, it can be a resin that maintains the adhesive force not only at room temperature but also at high temperature.

The high temperature adhesive and reinforced resin of the present invention may have a softening point of 75 캜 to 147 캜, preferably 80 캜 to 145 캜, and more preferably 130 캜 to 142 캜. If the softening point of the high-temperature cohesive strengthening resin exceeds 147 占 폚, there may arise a problem that the adhesive strength at room temperature significantly decreases. If the softening point is less than 75 占 폚, the adhesive strength at high temperature may significantly decrease.

The high-temperature cohesive strengthening resin of the present invention may have a weight average molecular weight of 100 to 5,000, preferably 500 to 3,000.

The high-temperature cohesive strengthening resin of the present invention may contain a modified reaction compound by reacting a compound represented by the following formula (2) with at least one selected from formaldehyde and phenol.

(2)

In formula (2), R ₄ , R ₅ , R ₆ , R ₇ and R ₈ are each independently -H, an alkyl group of C1 ~ C10, and the alcohol group or carboxyl group, preferably R ₄ is an alkyl group of C1 ~ C4, R ₅ is an alkyl group, R ₆ a -H or C1 ~ C4 are -H or an alkyl group of C1 ~ C5, R ₇ and R ₈ may be a carboxyl group, alcohol group, or an alkyl group of C1 ~ C4.

On the other hand, the pressure-sensitive adhesive layer of the present invention may contain 15 to 35 parts by weight, preferably 20 to 30 parts by weight, more preferably 23 to 27 parts by weight, of the high-temperature cohesive strengthening resin per 100 parts by weight of the acrylic polymer.

If the high-temperature cohesive strengthening resin is contained in an amount of less than 15 parts by weight based on 100 parts by weight of the acrylic weight, there may arise a problem of deterioration of the adhesive strength at high temperature, and if it exceeds 35 parts by weight, .

On the other hand, the pressure-sensitive adhesive layer of the present invention may further comprise a curing agent.

The curing agent is a substance for curing the pressure-sensitive adhesive layer, and may include at least one selected from an epoxy curing agent and an acrylic curing agent, and may preferably include an epoxy curing agent.

The pressure-sensitive adhesive layer of the present invention may contain 0.13 to 0.25 parts by weight, preferably 0.15 to 0.23 parts by weight, more preferably 0.16 to 0.21 part by weight of a curing agent based on 100 parts by weight of the acrylic polymer.

If the curing agent is contained in an amount of less than 0.13 parts by weight based on 100 parts by weight of the acrylic weight, the cohesive strength may be lowered. If the curing agent is contained in an amount exceeding 0.25 parts by weight,

Further, the pressure-sensitive adhesive layer of the present invention may further include a coupling agent.

The coupling agent enhances the interfacial adhesion of the pressure-sensitive adhesive layer and improves the properties of the composite material as a result of the adhesion, and may include a silane coupling agent as the coupling agent.

The pressure-sensitive adhesive layer of the present invention may contain 0.0001 to 0.002 part by weight, preferably 0.0005 to 0.0015 part by weight, more preferably 0.0008 to 0.0012 part by weight of a coupling agent based on 100 parts by weight of the acrylic polymer.

If the coupling agent is included in a range of 0.0001 to 0.002 part by weight based on 100 parts by weight of the acrylic weight, there may be a problem of deterioration of adhesion.

In addition, the pressure-sensitive adhesive layer of the present invention may further comprise a solvent, and the solvent may include at least one selected from ethyl acetate and methyl ethyl ketone, and preferably ethyl acetate.

On the other hand, the pressure-sensitive adhesive layer of the present invention has a pressure-sensitive adhesive layer of 0.70 to 1.0 kgf / inch at a temperature of 25 占 폚 and 0.7 to 1.2 kgf / inch at a temperature of 85 占 폚 in measuring the adhesive strength with a foam tape, according to KS T1028. inch. Thus, it is possible to have an excellent latent force not only at room temperature but also at high temperature.

Further, the coverlay film, the flexible circuit board and / or the portable electronic device of the present invention may include the aforementioned electromagnetic shielding and heat-radiation composite sheet, and the portable electronic device may be a flexible electronic device.

Specifically, the electromagnetic wave shielding and heat radiation composite sheet can be used as a shielding and heat dissipation component of electronic devices, 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.

On the other hand, the method for manufacturing an electromagnetic shielding and heat radiation composite sheet of the present invention is a method for manufacturing a composite sheet for electromagnetic shielding and heat radiation, which comprises pressing a laminate obtained by laminating a first electromagnetic wave shielding layer, a first adhesive layer, a graphite layer provided with a plurality of through holes, Or a hot press equipment, two steps of heating or pressing the laminate to perform a press or hot press process, and separating the composite sheet integrated from the press or hot press.

At this time, the pressure-sensitive adhesive layer may include an acrylic polymer having a glass transition temperature of -65 ° C to -25 ° C and a high-temperature adhesive resin having a softening point of 70 ° C to 147 ° C and a weight average molecular weight of 100 to 5,000.

Further, the graphite layer can satisfy the following equation (1).

[Equation 1]

(d2 + d3)? d1? 4 (d2 + d3)

D1 is the average thickness of the graphite layer, d2 is the average thickness of the first adhesive layer, and d3 is the average thickness of the second adhesive layer.

In addition, the graphite layer can satisfy the following equation (2).

[Equation 2]

d2? d3

d2 is the average thickness of the first adhesive layer, and d3 is the average thickness of the second adhesive layer.

The compositions and / or composition ratios of the electromagnetic wave shielding layer, the first adhesive layer, the graphite layer, the second adhesive layer, the support layer and the pressure-sensitive adhesive layer in the first step are the same as those described above.

In the second step, the hot press process is preferably performed at a temperature of 145 to 160 ° C and a pressure of 45 to 60 kgf / cm 2. If the temperature is lower than 145 ° C, the adhesive component is insufficiently melted, If it exceeds 160 ° C, the mechanical properties may deteriorate. If the pressure is less than 45 kgf / cm < 2 > during the two-stage hot pressing process, the amount of adhesive components of the first adhesive layer and the second adhesive may flow into the through holes of the graphite layer may be small, It 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, there may be a problem that the amount of the first adhesive and / or the second adhesive filled into the holes of the graphite 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.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. It will be understood that various changes and modifications may be made without departing from the scope of the present invention. For example, each component specifically illustrated in the embodiments of the present invention can be modified and implemented. It is to be understood that all changes and modifications that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Example  One

(TP-140, AK Chemtech) having a softening point of 140 占 폚, 25 parts by weight of a silane coupling agent (KBM- , 0.188 part by weight of an epoxy curing agent (X-500, AK Chemtech) and 2.5 parts by weight of ethyl acetate were dissolved at room temperature (25 占 폚) to prepare a pressure-sensitive adhesive.

Example  2 to 3, Comparative Example  1-2

A pressure-sensitive adhesive was prepared in the same manner as in Example 1. However, as shown in Table 1 below, the pressure-sensitive adhesive was prepared by using different high-temperature pressure-sensitive adhesive resins.

Example  4

A pressure-sensitive adhesive was prepared in the same manner as in Example 1. Except that 20 parts by weight of a high temperature adhesive resin (TP-140, AK Chemtech) having a softening point of 140 占 폚 was added to 100 parts by weight of an acrylic polymer (Ex 409, AK Chemtech) having a glass transition temperature of -45 占To prepare a pressure-sensitive adhesive.

Example  5

A pressure-sensitive adhesive was prepared in the same manner as in Example 1. Except that 30 parts by weight of a high temperature adhesive resin (TP-140, AK Chemtech) having a softening point of 140 占 폚 was added to 100 parts by weight of an acrylic polymer (Ex 409, AK Chemtech) having a glass transition temperature of -45 占To prepare a pressure-sensitive adhesive.

Comparative Example  3

A pressure-sensitive adhesive was prepared in the same manner as in Example 1. Except that 11 parts by weight of a high temperature adhesive resin (TP-140, AK Chemtech) having a softening point of 140 占 폚 was added to 100 parts by weight of an acrylic polymer (Ex 409, AK Chemtech) having a glass transition temperature of -45 占To prepare a pressure-sensitive adhesive.

Comparative Example  4

A pressure-sensitive adhesive was prepared in the same manner as in Example 1. Except that 30 parts by weight of a high temperature adhesive resin (TP-140, AK Chemtech) having a softening point of 140 占 폚 was added to 100 parts by weight of an acrylic polymer (Ex 409, AK Chemtech) having a glass transition temperature of -45 占To prepare a pressure-sensitive adhesive.

Comparative Example  5

A pressure-sensitive adhesive was prepared in the same manner as in Example 1. A pressure-sensitive adhesive was produced without using a high-temperature adhesive resin.

Experimental Example  One

The pressure-sensitive adhesives prepared in Examples 1 to 5 and Comparative Examples 1 to 5 were evaluated on the basis of the following physical property evaluation methods, and the results are shown in Tables 1 and 2.

(1) Adhesive strength

1) At room temperature (25 ℃)

Each of the pressure-sensitive adhesives prepared in Examples 1 to 5 and Comparative Examples 1 to 5 was attached to a foam tape on one side thereof and a Tesa tape on the other side thereof, and after reciprocating 5 times with a 2 kgf Hand Roller, Min.

Thereafter, the adhesive strength to the foam tape was measured at room temperature (25 DEG C) using UTM (180 DEG Peel, 300 mm / min).

2) High temperature (85 ℃) measurement method

Each of the pressure-sensitive adhesives prepared in Examples 1 to 5 and Comparative Examples 1 to 5 was attached to a foam tape on one side thereof and a Tesa tape on the other side thereof, and after reciprocating 5 times with a 2 kgf Hand Roller, Min.

Thereafter, it was placed in a Chamber UTM (180 ° Peel, 300 mm / min) and allowed to stand at 85 ° C for 30 minutes, and then the adhesive strength to the foam tape was measured.

High-temperature cohesive strength resin of Example 1: AK Chemtech, TP-140 (softening point: 140 占 폚)

High-temperature cohesive strength resin of Example 2: Raton Korea, DX-200 (softening point: 145 占 폚)

High-temperature cohesive strength resin of Example 3: Achhemtech, HYDROGRAL (softening point: 80 占 폚)

High-temperature cohesive strength resin of Comparative Example 1: Raton Korea, DX-140 (softening point: 150 占 폚)

High-temperature adhesive resin of Comparative Example 2: Achhemtech, HYDROGRAL M (softening point: 50 캜)

As shown in Tables 1 and 2, it was confirmed that the pressure-sensitive adhesive of Examples 1 to 3 showed excellent adhesive strength not only at room temperature (25 ° C) but also at high temperature (85 ° C) It was confirmed that the adhesive exhibited the best adhesive strength not only at room temperature (25 ° C) but also at high temperature (85 ° C).

The pressure-sensitive adhesive of Comparative Example 1 is similar in pressure-sensitive adhesive strength at high temperature (85 ° C) to those of Pressure-Sensitive Adhesive Examples 1 to 3, but the pressure-sensitive adhesive at room temperature (25 ° C) And it was confirmed that it was remarkably decreased.

The pressure-sensitive adhesive of Comparative Example 2 is similar in pressure-sensitive adhesive strength at room temperature (25 ° C) to that of Pressure-Sensitive Pressure-Sensitive Adhesive Examples 1 to 3, but the pressure-sensitive adhesive at high temperature (85 ° C) It was confirmed that the decrease was remarkable

In addition, it was confirmed that the pressure-sensitive adhesive of Examples 1 and 4 to 5 exhibited excellent adhesive strength not only at room temperature (25 ° C) but also at high temperature (85 ° C) In addition, it was confirmed that the highest adhesive strength was exhibited even at a high temperature (85 ° C).

The pressure-sensitive adhesive of Comparative Example 3 was similar in pressure-sensitive adhesive strength at room temperature (25 ° C) to that of Pressure-Sensitive Adhesive of Examples 1 and 4 to 5 but the adhesive strength at high temperature (85 ° C) It was confirmed that the pressure-sensitive adhesive was significantly lower than the pressure-sensitive adhesive.

The pressure-sensitive adhesive of Comparative Example 4 was similar in pressure-sensitive adhesive strength at high temperature (85 ° C) to that of Pressure-Sensitive Adhesive of Examples 1 and 4 to 5, but the adhesive strength at room temperature (25 ° C) It was confirmed that the pressure-sensitive adhesive was significantly lower than the pressure-sensitive adhesive.

The pressure-sensitive adhesive of Comparative Example 5 was similar in pressure-sensitive adhesive strength at room temperature (85 ° C) to that of Pressure-Sensitive Adhesive of Examples 1 and 4 to 5 but the adhesive strength at high temperature (25 ° C) It was confirmed that the pressure-sensitive adhesive was significantly lower than the pressure-sensitive adhesive.

Preparation Example  One : Through hole  Equipped Graphite  Manufacture of sheet

A plurality of circular through-holes 1 were formed in a graphite sheet (T company, TGS17) having an average thickness of 17 탆 so as to intersect odd rows and even rows (see the schematic diagram of FIG. 4).

The perforated hole 1 has an average diameter of 3 mm, the longitudinal axial distance between the center portions of the through holes is 10 mm, the minor axial distance is 12 mm, and the total area of the through holes is the total area of the upper surface of the sheet of graphite 10 4.0% of the through holes were formed, and the degree of deformation of the through holes was 0.866 based on the following equation (2).

&Quot; (2) "

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

Preparation Example  2 to 8 and Example of comparison preparation  1-4

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

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

Example of comparison preparation  5

A graphite sheet was prepared in the same manner as in the graphite sheet of Preparation Example 1. However, the plurality of circular through-holes formed in the graphite sheet do not form the intersection of the odd-numbered columns and the even-numbered through-holes, but form through-holes corresponding to the center line in the x- and y-axis directions. (See FIG. 2A)

Example  6: Manufacture of electromagnetic shielding and heat-radiating composite sheet

An adhesive (thermosetting resin) was coated on one side of the copper foil (electromagnetic wave shielding layer), and then semi-cured to form a first adhesive layer.

Separately, an adhesive (thermosetting resin) was applied to one surface of a polyimide (PI) resin (support layer), and then semi-cured to form a second adhesive layer.

Next, after the electromagnetic wave shielding layers were laminated by bonding, the graphite sheet (graphite layer) prepared in Preparation Example 1 was laminated on the first adhesive layer.

Next, a support layer was laminated on the top of the graphite sheet so that the second adhesive layer and the graphite sheet were laminated.

Next, after a pressure-sensitive adhesive (pressure-sensitive adhesive layer) was laminated on the support layer, the sheet laminated with the electromagnetic wave shielding layer-first adhesive layer-graphite layer-second adhesive layer-support layer-pressure- (hot press) equipment.

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, the sheet was cooled to 60 deg. C at a rate of 4.5 deg. C / minute, and then the thermally compressed sheet was taken out from the hot press to form a first adhesive layer and a second adhesive layer in the through holes of the graphite layer as shown in Fig. And a filled electromagnetic wave shielding and heat-radiating composite sheet.

The total thickness of the manufactured electromagnetic shielding and heat-radiating composite sheet was 96 m, the average thickness of the electromagnetic wave shielding layer was 18 m, the average thickness of the first adhesive layer was 5 m, the average thickness of the graphite layer was 17 m, The average thickness of the support layer was 25 占 퐉, and the average thickness of the pressure-sensitive adhesive layer was 26 占 퐉.

Example  7-13 and Comparative Example  6 to 10

The electromagnetic wave shielding and heat radiation composite sheet was produced in the same manner as in the electromagnetic wave shielding and heat radiation composite sheet of Example 6. However, as shown in Table 4 below, each of the electromagnetic wave shielding and heat radiation composite sheets of Examples 7 to 13 and Comparative Examples 6 to 10 was produced by using the graphite sheet different from that of the used electromagnetic shielding and heat radiation composite sheet.

Experimental Example  2: peel strength and Thermal diffusivity  Measure

(1) Overall peel strength (gf / cm ² ) of graphite layer and peel strength (gf / Hole) per through hole

The electromagnetic wave shielding and heat-radiating composite sheet prepared in each of Examples 6 to 13 and Comparative Examples 6 to 10 was prepared according to JIS C 6741, and the peel strength of the graphite layer as a whole was measured using a 180 ° peel test 180 Peel Test). The results are shown in Table 4 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 electromagnetic wave shielding and heat-radiating composite sheet produced in each of Examples 6 to 13 and Comparative Examples 6 to 10 was cut into a size of 100 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, the better the horizontal thermal conductivity and the heat radiation performance.

As can be seen from Table 4, in Examples 6 to 13, the total peel strength was 600 gf / cm ² or more and the peel strength per pass hole was at least 400 gf / hole, It was confirmed that not only the adhesiveness was uniformly lower than 200 gf / hole but also the difference (ΔT) between the hot spot and the cold spot was 23 ° C. or less.

In contrast, in Comparative Example 6 in which a graphite sheet having a degree of deformation of a through hole of 1.500 was applied, the peel strength was excellent, but it was found that there was a problem that the thermal diffusivity was drastically increased by ΔT = 24.89.

It was also confirmed that the peel strength was significantly lowered in Comparative Example 7 in which a graphite sheet having a through-hole degree of 0.485 was applied.

On the other hand, in Comparative Example 8 in which d = 1.7 L, the thermal conductivity is excellent as compared with Example 6 in which d = 0.833 L, but not only the total peel strength is low, but the maximum and minimum peel strength difference per through hole is as high as 274 gf / It was confirmed that the adhesiveness was not uniform.

Further, in Comparative Example 9 in which d = 0.2 L, the horizontal thermal conductivity was lowered as compared with Example 6 in which d = 0.833 L, which is significantly higher than the hot spot and the cold spot difference.

As compared with Comparative Example 10 (Cross-Forming X) in which the y-axis through holes of the odd-numbered columns and the even-numbered columns were made to have the same reference, the maximum and minimum values of the peel strength per through hole were 200 it was confirmed that the uniformity of the adhesion of the graphite sheet to gf / hole was significantly lower than that of Example 6.

Example  14 and Comparative Example  11-12

The electromagnetic wave shielding and heat radiation composite sheet was produced in the same manner as in the electromagnetic wave shielding and heat radiation composite sheet of Example 6. However, as shown in the following Table 5, in each of the electromagnetic wave shielding and heat radiation composite sheets of Example 14 and Comparative Examples 11 to 12, the electromagnetic wave shielding and heat radiation composite sheet was produced with different thicknesses of the first adhesive layer and the second adhesive layer .

The peel strength and the thermal diffusivity were measured in the same manner as in Experimental Example 2, and the results are shown in Table 6 below.

As can be seen from the above Table 6, it can be confirmed through comparison between Examples 6 and 14 that the thickness variation of the first adhesive layer and the second adhesive layer influences the peel strength and thermal diffusivity, and when the second adhesive layer becomes thick It was confirmed that the peel strength was increased, but the thermal diffusivity tended to be somewhat lower.

In the case of Comparative Example 11 in which the average thickness d1 of the graphite layer was smaller than the sum of the first adhesive layer thickness d2 and the second adhesive layer thickness d3, the total peel strength and peel strength per hole were excellent However, there is a problem that the heat dissipation effect is lowered because the difference between the hot spot and the cold spot is 25.67, which is disadvantageous to the composite sheet flaking, and the flexibility of the composite sheet is poor.

In the case of Comparative Example 12 in which the average thickness d1 of the graphite layer exceeds 4 (the thickness of the first adhesive layer (d2) + the thickness of the second adhesive layer (d3)), the first and second adhesive layers are too The adhesive component is not sufficiently filled in the hole in the graphite layer and the peel strength per hole of the graphite layer is too low.

In the case of Comparative Example 13 in which the first adhesive layer thickness d2 was larger than the second adhesive layer thickness d3, the difference between the hot spot and the cold spot was 23.96, and the difference between the hot spot and the cold spot was 22.20. There is a problem that the thermal diffusivity is rather reduced.

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 layer
20: electromagnetic wave shielding layer
30: first adhesive layer
40: second adhesive layer
50: support layer
60: pressure-sensitive adhesive layer

Claims (15)

An electromagnetic wave shielding layer; A first adhesive layer; A graphite layer having a plurality of through holes; A second adhesive layer; A support layer; And a pressure-sensitive adhesive layer are sequentially laminated,
Wherein the pressure-sensitive adhesive layer has an acrylic polymer having a glass transition temperature of -65 占 폚 to -25 占 폚; And
A high-temperature cohesive strengthening resin having a softening point of 70 ° C to 147 ° C and a weight average molecular weight of 100 to 5,000,
Wherein the graphite layer satisfies the following equation (1): " (1) "
[Equation 1]
(d2 + d3)? d1? 4 (d2 + d3)
D1 is the average thickness of the graphite layer, d2 is the average thickness of the first adhesive layer, and d3 is the average thickness of the second adhesive layer.
The method according to claim 1,
Wherein the first adhesive layer and the second adhesive layer satisfy the following equation (2).
[Equation 2]
d2? d3
d2 is the average thickness of the first adhesive layer, and d3 is the average thickness of the second adhesive layer.
The method according to claim 1,
Wherein the inside of the through hole of the graphite layer is filled with an adhesive derived from the first adhesive layer and the second adhesive layer.
The method according to claim 1,
The acrylic polymer has a glass transition temperature of -54 캜 to -36 캜,
Wherein the high-temperature cohesive strengthening resin has a softening point of 80 to 145 占 폚 and a weight average molecular weight of 500 to 3,000.
The method according to claim 1,
Wherein the acrylic polymer comprises a compound represented by the following general formula (1).
[Chemical Formula 1]

In Formula 1, R ₁ , R ₂ and R ₃ are each independently -H, -OH, a C 1 to C 10 alkyl group or a C 1 to C 5 alkoxy group, and n has a weight average molecular weight of 200,000 to 150,000 It is rational number.
The method according to claim 1,
Wherein the high-temperature cohesive strengthening resin comprises a reaction compound modified by reacting a compound represented by the following formula (2) with at least one selected from formaldehyde and phenol;
(2)

In Formula 2, R ₄ , R ₅ , R ₆ , R ₇ and R ₈ is each independently -H, a C1-C10 alkyl group, an alcohol group or a carboxyl group.
The method according to claim 1,
Wherein the pressure-sensitive adhesive layer comprises 15 to 35 parts by weight of a high-temperature cohesive strengthening resin per 100 parts by weight of the acrylic polymer.
The method according to claim 1,
Wherein the pressure-sensitive adhesive layer further comprises a curing agent,
Wherein the curing agent comprises at least one selected from an epoxy curing agent and an acrylic curing agent,
Wherein the curing agent comprises 0.13 to 0.25 parts by weight based on 100 parts by weight of the acrylic polymer.
The method according to claim 1,
Wherein the pressure-sensitive adhesive layer further comprises a silane coupling agent,
Wherein the silane coupling agent comprises 0.0001 to 0.002 parts by weight based on 100 parts by weight of the acrylic polymer.
The method according to claim 1,
Wherein the pressure-sensitive adhesive layer has a thickness of 0.70 to 1.0 kgf / inch at a temperature of 25 占 폚 and 0.7 to 1.2 kgf / inch at a temperature of 85 占 폚 according to KS T1028 standard, Shielding and heat dissipation composite sheet.
A coverlay film comprising the electromagnetic wave shielding and heat-radiating composite sheet according to any one of claims 1 to 10.
The flexible circuit board according to any one of claims 1 to 10, which comprises the electromagnetic wave shielding and heat radiation composite sheet.
10. A portable electronic device comprising the electromagnetic wave shielding and heat-radiating composite sheet according to any one of claims 1 to 10.
A step of putting a laminate having an electromagnetic wave shielding layer, a first adhesive layer, a graphite layer having a plurality of through holes, a second adhesive layer, a support layer and a pressure-sensitive adhesive layer in this order on a hot press machine;
Two steps of heating and pressing the laminate under a pressure of 145 to 160 DEG C and 45 to 60 kgf / cm < 2 > for 50 to 70 minutes; And
Three steps of cooling the hot press and then separating the composite sheet integrated from the hot press;
Lt; / RTI >
Wherein the pressure-sensitive adhesive layer has an acrylic polymer having a glass transition temperature of -65 占 폚 to -25 占 폚; And
A high-temperature cohesive strengthening resin having a softening point of 70 ° C to 147 ° C and a weight average molecular weight of 100 to 5,000,
Wherein the graphite layer satisfies the following equation (1): < EMI ID = 1.0 >
[Equation 1]
(d2 + d3)? d1? 4 (d2 + d3)
D1 is the average thickness of the graphite layer, d2 is the average thickness of the first adhesive layer, and d3 is the average thickness of the second adhesive layer.
15. The method of claim 14,
Wherein the first adhesive layer and the second adhesive layer satisfy the following equation (2): < EMI ID = 1.0 >
[Equation 2]
d2? d3
d2 is the average thickness of the first adhesive layer, and d3 is the average thickness of the second adhesive layer.

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