JP2017118025A - Electromagnetic shielding heat dissipation sheet and heat spreader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electromagnetic shielding heat dissipation sheet which is superior in electromagnetic shielding property, and which can efficiently diffuse and dissipate heat generated by an electronic component or the like.SOLUTION: An electromagnetic shielding heat dissipation sheet 10 comprises: a protection layer 1; a heat-radiation layer 2; and a metal layer 3. The heat-radiation layer 2 includes a heat-radiation filler, a magnetic material and a binder. The protection layer 1 is disposed for the purpose of protecting the heat-radiation layer, and it has an average thickness of 1-50 μm preferably. The magnetic material used for the heat-radiation layer 2 is preferably ferrite or soft magnetic metal. For the metal layer 3, gold, silver, copper, iron, nickel, aluminum or alloys of the metals may be used.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electromagnetic shielding heat radiation sheet and a heat spreader.

  In recent years, electronic components such as semiconductor chips, transistors, capacitors, and capacitors, and electrical components such as batteries (batteries) have been further improved in performance. Along with this, the amount of heat generated by electronic parts and electrical parts is increasing. When electronic parts and electrical parts become hot, their lifetime may be shortened and reliability may be reduced.

  For this reason, conventionally, heat sinks and heat spreaders for dissipating the heat generated by electronic components and electrical components are attached. As the heat spreader, a material obtained by bonding an adhesive tape to a metal foil having thermal conductivity such as an aluminum foil or a copper foil is often used.

  In recent years, an electromagnetic shielding and heat radiating sheet that is excellent in electromagnetic shielding characteristics as well as heat radiating properties has been demanded in devices on which electronic components and electrical components are mounted in order to perform high-density mounting in a space-saving manner.

Although the metal foil tape used for the heat spreader has electromagnetic shielding properties, the electromagnetic shielding properties in a low frequency region particularly in a magnetic field of 0.1 MHz to 1.0 MHz are insufficient.
As a means for enhancing electromagnetic shielding properties in a low frequency region, for example, Patent Document 1 discloses a magnetic field shielding electromagnetic shielding material in which non-metallic fibers and metallic fibers are interwoven and the surface of the interwoven fabric is metal-plated. Yes. Patent Document 2 describes that electromagnetic shielding properties can be improved by mixing an electromagnetic shielding material into a resin.

JP 2014-45047 A JP 2001-68889 A

  However, the magnetic field shielding electromagnetic shielding material described in Patent Document 1 improves the electromagnetic shielding properties at the expense of the function of the metal foil as a heat spreader. Therefore, the magnetic field shielding electromagnetic shielding material described in Patent Document 1 does not have sufficient heat dissipation. Although the electromagnetic shielding material disclosed in Patent Document 2 has excellent electromagnetic shielding properties, it does not fundamentally have heat dissipation performance. Therefore, when heat dissipation is required, a separate heat dissipation sheet or the like must be used, which hinders space saving. In recent years, high-density mounting of electronic devices requires both heat dissipation and electromagnetic shielding characteristics, and the development of materials that enable more efficient heat dissipation and electromagnetic shielding has been demanded.

  The present invention has been made in view of the above circumstances, and the problem to be solved by the present invention is an electromagnetic shielding and heat radiating sheet that has excellent electromagnetic shielding characteristics and can efficiently diffuse and dissipate heat generated by electronic components and the like. Is to provide.

As a result of intensive studies, the inventors of the present invention have a high heat radiation filler, magnetic material, and binder in the heat radiation layer of the electromagnetic shielding heat radiation sheet having the protective layer, the heat radiation layer, and the metal layer in this order. It was found that electromagnetic shielding and heat dissipation can be realized.
In addition, by providing a protective layer on the heat radiation layer, it is possible to avoid damage to the heat radiation characteristics due to physical impact, etc., even in a space-saving package with high density. I found it. Here, providing the protective layer on the heat radiation layer may hinder the heat radiation, and is not performed from the ordinary technical common knowledge of those skilled in the art.
Further, it has been found that by further providing a predetermined adhesive layer, it is possible to provide both the bonding property to the heating element and the thermal conductivity to the heat radiation layer.
That is, the present invention has the following configuration.

(1) The electromagnetic shielding heat radiation sheet which concerns on 1 aspect of this invention has a protective layer, a heat radiation layer, and a metal layer in order, and the said heat radiation layer contains a heat radiation filler, a magnetic body, and a binder. .
(2) In the electromagnetic shielding and heat-dissipating sheet according to (1), the average thickness of the metal layer may be 3 to 100 μm.
(3) In the electromagnetic shielding and heat-dissipating sheet according to any one of (1) and (2), the protective layer may have an average thickness of 1 to 50 μm.
(4) In the electromagnetic shielding and heat-radiating sheet according to any one of (1) to (3), an average thickness of the heat radiation layer may be 0.1 to 5 μm.
(5) In the electromagnetic shielding and heat radiating sheet according to any one of (1) to (4), the heat radiation filler may be a carbonaceous material.

(6) In the electromagnetic shielding heat radiation sheet according to any one of (1) to (5), the magnetic body may be ferrite or a soft magnetic metal.
(7) In the electromagnetic shielding heat radiation sheet according to any one of (1) to (6) above, at least one of the binders is crosslinked with at least one of an epoxy resin and a polymer polysaccharide by an acid crosslinking agent. It may be a thing.
(8) In the electromagnetic shielding and heat-radiating sheet according to any one of (1) to (7), the metal layer may further include an adhesive layer on a surface opposite to the heat radiation layer side.
(9) In the electromagnetic shielding and heat-radiating sheet as described in (8) above, the adhesive layer may have an average thickness of 5 to 50 μm.
(10) In the electromagnetic shielding heat radiation sheet according to any one of (8) and (9), the adhesive layer may contain a conductive filler.

(11) In the electromagnetic shielding and heat-dissipating sheet according to any one of (8) to (10), a release sheet may further be provided on the surface of the adhesive layer opposite to the metal layer.
(12) In the electromagnetic shielding and heat radiating sheet according to any one of (1) to (11), the protective layer is polyethylene terephthalate.
(13) The heat spreader which concerns on 1 aspect of this invention contains the electromagnetic shielding heat radiating sheet as described in any one of said (1)-(12).

  The electromagnetic shielding and radiating sheet according to one embodiment of the present invention has excellent electromagnetic shielding characteristics and can efficiently diffuse and dissipate heat generated by electronic components and the like.

It is the figure which showed typically the cross section of the electromagnetic shielding thermal radiation sheet concerning 1 aspect of this invention. It is the figure which showed typically the cross section of the electromagnetic shielding thermal radiation sheet concerning another aspect of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following embodiments, and it is easy for those skilled in the art to change the modes and details in various ways without departing from the spirit and scope of the present invention. Understood. Therefore, the present invention should not be construed as being limited to the description of the embodiments below.

FIG. 1 is a diagram schematically showing a cross section of an electromagnetic shielding and heat radiating sheet according to one embodiment of the present invention. Moreover, FIG. 2 is the figure which showed typically the cross section of the electromagnetic wave shielding thermal radiation sheet which concerns on another aspect of this invention. 1 has a protective layer 1, a heat radiation layer 2 containing a heat radiation filler, a magnetic material and a binder, and a metal layer 3 in this order.
The electromagnetic shielding heat radiation sheet 20 shown in FIG. 2 has a protective layer 1, a heat radiation layer 2 containing a heat radiation filler, a magnetic material and a binder, a metal layer 3, an adhesive layer 4, and a release sheet 5. When using the electromagnetic shielding heat radiation sheet 20, the release sheet 5 is peeled to expose the adhesive layer 4. Moreover, you may have another layer between each layer.
Here, the “average thickness” refers to a value obtained as an arithmetic average value by observing the cross sections of the electromagnetic shielding and heat radiating sheets 10 and 20 and measuring the thickness at 10 randomly selected locations.

<Protective layer>
The protective layer 1 is a layer that becomes the outermost layer when the electromagnetic shielding / radiating sheet 10 or the electromagnetic shielding / radiating sheet 20 is bonded to a heating element such as an electronic component.

The protective layer 1 is disposed for the purpose of protecting the heat radiation layer, and preferably has an average thickness of 1 to 50 μm. More preferably, the average thickness is 2 to 25 μm. When the average thickness is 1 to 50 μm, the heat radiation layer can be protected from an external impact.
Moreover, it is preferable that the protective layer 1 has electrical insulation. Here, the insulating property means that the insulating property can be maintained without being broken down even when a voltage of 0.5 to 5 kV is applied to both surfaces of the protective layer 1, for example.
Since the protective layer 1 has an insulating property, it can be used even in an electronic component or the like that requires insulating properties. Moreover, if the average thickness of the protective layer 1 having insulating properties is the above-described thickness, high insulating properties and high heat dissipation properties can be maintained.

  It does not specifically limit as a material which comprises the protective layer 1, A well-known resin material can be used. For example, polyolefin resin, polyester resin, (meth) acrylic resin, urethane resin, epoxy resin, oxetane resin, vinyl ester resin, vinyl ether resin, silicone resin, fluorine resin, etc. Two or more kinds can be used. Further, the resin may be any of thermoplasticity, thermosetting, and photocuring. Among these, from the viewpoint of versatility, polyolefin resins and polyester resins are preferable, among which polyester resins are preferable, and among these, polyethylene terephthalate is more preferable.

  The method for laminating the protective layer 1 on the heat radiation layer 2 is not particularly limited. For example, the resin used as the protective layer 1 is melt-extruded and laminated on the heat radiation layer 2, or the protective layer 1 previously formed into a film shape is bonded to the heat radiation layer 2 with various adhesives and adhesives. There is a method or a method of coating a resin to be the protective layer 1 on the heat radiation layer 2.

  The electromagnetic shielding and radiating sheet 10 and the electromagnetic shielding and radiating sheet 20 have the protective layer 1 as described above, and thus can protect the thermal radiation layer 2 and the like, which will be described later, from external impacts. As a result, the wear resistance of the electromagnetic shielding and radiating sheet 10 and the electromagnetic shielding and radiating sheet 20 can be improved. Further, since the protective layer 1 has an insulating property, it can be used even in a place that requires space saving and insulating properties such as an electronic component. That is, even if an impact or deformation is applied to the electromagnetic shielding and radiating sheet 10 or the electromagnetic shielding and radiating sheet 20, heat dissipation and insulation can be maintained.

<Thermal radiation layer>
The heat radiation layer 2 contains a heat radiation filler, a magnetic material, and a binder. When the heat radiation layer 2 contains a magnetic material, electromagnetic shielding properties can be enhanced. In particular, the electromagnetic shielding property in a low frequency region in a magnetic field of 0.1 MHz to 1.0 MHz can be enhanced.

  The heat radiation filler used for the heat radiation layer 2 is not particularly limited as long as it has an emissivity of 0.8 or more, regardless of whether it is a metal or a nonmetal. From the viewpoint of high thermal emissivity and low cost, a carbonaceous material is preferable. Examples of the carbonaceous material include carbon black such as acetylene black and ketjen black, graphite, vapor grown carbon fiber, and the like, and one or more of them may be selected and used. The particle size of the thermal radiation filler is preferably 0.1 to 2.0 μm, more preferably 0.2 to 1 μm, with a cumulative mass 50% particle size (D50). When the cumulative mass 50% particle diameter (D50) is 0.1 to 2.0 μm, a heat radiation layer with high smoothness can be obtained.

  The magnetic material used for the heat radiation layer 2 is preferably ferrite or soft magnetic metal. This is because ferrite or soft magnetic metal is a magnetic loss material and is optimal as a noise electromagnetic wave suppression / absorber in a near electromagnetic field. From the viewpoint of price, ferrite is preferable.

Examples of the ferrite include spinel type ferrite, ferro-sprayer (Y type, Z type) type hexagonal ferrite, and magneplumbite (M type) type hexagonal ferrite. Examples of the spinel ferrite include Mg—Zn ferrite, Ni—Zn ferrite, and Mn—Zn ferrite. As ferrosprayer (Y type, Z type) type hexagonal ferrite, Ba ₂ Co ₂ Fe ₁₂ O ₂₂ , Ba ₂ Ni ₂ Fe ₁₂ O ₂₂ , Ba ₂ Zn ₂ Fe ₁₂ O ₂₂ , Ba ₂ Mn ₂ Fe ₁₂ O ₂₂ , Ba ₂ Mg ₂ Fe ₁₂ O ₂₂ , Ba ₂ Cu ₂ Fe ₁₂ O _22, or Ba ₃ Co ₂ Fe ₂₄ O ₄₁ may be mentioned. As magneplumbite (M type) hexagonal ferrite, the Fe elements of BaFe ₁₂ O ₁₉ , SrFe ₁₂ O ₁₉ , BaFe ₁₂ O ₁₉ , SrFe ₁₂ O ₁₉ are Ti, Co, Mn, Cu, Zn, Ni, Mg And those substituted with.

As soft magnetic metals, carbonyl iron, electrolytic iron, Fe—Cr alloy, Fe—Si alloy, Fe—Ni alloy, Fe—Al alloy, Fe—Co alloy, Fe—Al—Si alloy, Fe-Cr-Si alloys, Fe-Cr-Al alloys, Fe-Si-Ni alloys and Fe-Si-Cr-Ni alloys can be mentioned.
The shape of the magnetic material is not particularly limited, but a spherical shape, a rod shape, a flat shape, a fiber shape, a square shape, a lump shape, or the like can be used. From the viewpoint of coatability, a spherical shape or a flat shape is preferable. From the viewpoint of enhancing electromagnetic shielding properties, a flat shape is preferable. If the shape of the magnetic material is powder, the particle size range measured using a cumulative mass 50% particle size (D50) is preferably 0.1 to 50.0 μm.

  The binder used for the heat radiation layer 2 is not particularly limited as long as it is a material capable of binding the heat radiation filler and the magnetic material. From the viewpoint of the binding properties of the heat radiation filler and the magnetic material, the coating properties of the composition of the heat radiation filler, the magnetic material and the binder, and the film performance as the heat radiation layer 2, the binder may be thermosetting or photocurable. The resin is preferred. As the photocurable resin, for example, an epoxy resin, an oxetane resin, a vinyl ether resin, a polysiloxane resin, a vinyl ester resin, or a (meth) acrylic resin can be used. Examples of the thermosetting resin include an epoxy resin, an oxetane resin, a polysiloxane resin, an unsaturated polyester resin, a vinyl ester resin, a phenol resin, a novolac resin, an amino resin, a (meth) acrylic resin having a crosslinkable functional group, or High molecular polysaccharides and the like can be used.

As the curable resin used as the binder, a thermosetting epoxy resin or a high molecular polysaccharide is preferable in terms of durability and adhesion, and it is more preferable to crosslink these with an acid crosslinking agent and cure.
Examples of the epoxy resin include diglycidyl ether of bisphenol A, diglycidyl ether of bisphenol F, diglycidyl ether of biphenol, and the like, and one kind or two or more kinds can be used.
Examples of the polymeric polysaccharide include one or more selected from chitosan, chitin and derivatives thereof.
Examples of acid crosslinking agents include phthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, trimellitic anhydride, tetrahydrophthalic anhydride, pyromellitic anhydride, dodecyl succinic anhydride, methyl nadic anhydride, benzophenone tetra Examples thereof include acid anhydrides such as carboxylic acid and butanetetracarboxylic anhydride, and one or more can be used.

  The content of the heat radiation filler in the heat radiation layer 2 is preferably 10 to 50 mass%, more preferably 30 to 40 mass%. By being in this range, there is an advantage that the heat radiation filler is close to the thermal emissivity of the single substance and heat dissipation is improved. The content of the magnetic substance in the heat radiation layer 2 is preferably 30 to 70% by mass, more preferably 40 to 50% by mass. By being within this range, the heat radiation layer can be provided with a magnetic field shielding property. The binder content in the heat radiation layer 2 is preferably 20 to 60% by mass, more preferably 30 to 40% by mass. Within this range, there is a merit of supporting the heat radiation filler on the substrate. Each content of a heat radiation filler, a magnetic body, and a binder is selected so that it may not exceed 100 mass% in total.

The formation method of the heat radiation layer 2 is not particularly limited. For example, the heat radiation layer 2 can be formed by applying and curing a composition containing a heat radiation filler, a magnetic substance, and a binder on the protective layer 1 or the metal layer 3.
The composition containing the heat radiation filler, the magnetic material and the binder may be diluted with a solvent as necessary, and then applied, dried and further cured to form the heat radiation layer 2.
As a coating method of a composition containing a heat radiation filler, a magnetic substance and a binder, gravure coating capable of forming a thin film having a uniform thickness is preferable.

  The average thickness of the heat radiation layer 2 is preferably 0.1 to 5 μm, and more preferably 0.5 to 3 μm. If the average thickness of the heat radiation layer is 0.1 to 5 μm, a sufficient amount of heat radiation filler and magnetic material in the heat radiation layer can be secured, and sufficient heat dissipation and electromagnetic shielding properties can be obtained.

<Metal layer>
The metal layer 3 is provided between the heat radiation layer 2 and a heating element such as an electronic component. Since the metal layer 3 has high thermal conductivity, the heat generated by the heating element can be efficiently transmitted to the heat radiation layer 2. Furthermore, it has electromagnetic shielding properties and can protect electronic components and the like from electromagnetic waves.

  As the metal layer 3, gold, silver, copper, iron, nickel, aluminum or an alloy containing these metals can be used. Among these, a metal having high thermal conductivity is preferable, and from the viewpoint of low cost and ease of processing, it is preferable to use copper, aluminum, or an alloy containing these metals as the metal layer 3.

  The average thickness of the metal layer 3 is preferably 3 to 100 μm, and more preferably 3 to 50 μm. When the average thickness of the metal layer 3 is 3 μm or more, the electromagnetic shielding and radiating sheet 10 or the electromagnetic shielding and radiating sheet 20 having excellent heat radiation and electromagnetic shielding properties can be obtained, and the electromagnetic shielding and radiating sheet 10 or the electromagnetic shielding and radiating sheet 20 can be obtained. There is little distortion and deformation of the metal layer 3 in the manufacturing process. When the average thickness of the metal layer 3 is 100 μm or less, the shape of the electromagnetic shielding and radiating sheet 10 or the electromagnetic shielding and radiating sheet 20 follows the shape of the heating element when the electromagnetic shielding and radiating sheet 10 is joined to the heating element. Sufficient sex can be secured. Therefore, even when the surface of the heating element is a curved surface, a sufficient contact area between the heating element and the electromagnetic shielding and radiating sheet 10 or the electromagnetic shielding and radiating sheet 20 can be secured, so that the heat of the heating element is efficiently radiated. can do.

<Adhesive layer>
The adhesive layer 4 is a layer for joining the electromagnetic shielding heat radiation sheet 20 to a heating element such as an electronic device.
The pressure-sensitive adhesive used for the pressure-sensitive adhesive layer 4 is not particularly limited. It is sufficient that the insulating properties and the adhesive strength are sufficient, and silicone-based adhesives, acrylic-based adhesives, urethane-based adhesives, rubber-based adhesives, and the like can be used. Especially, it is preferable to use an acrylic adhesive from the point of adhesive force.
As the pressure-sensitive adhesive, either a solvent-containing one or a solvent-free one can be used. For the purpose of increasing the cohesive strength of the pressure-sensitive adhesive, a curing agent corresponding to the pressure-sensitive adhesive may be included. As the curing agent, for example, an isocyanate compound, an epoxy compound, an aziridine compound, a melamine compound, or the like can be used.
Examples of the method for forming the pressure-sensitive adhesive layer 4 include a method in which a pressure-sensitive adhesive diluted with a solvent is applied to one surface of the metal layer 3 or the release sheet 5 and dried and thermally cured.

  The average thickness of the pressure-sensitive adhesive layer 4 is preferably 5 to 50 μm, and more preferably 8 to 20 μm. When the average thickness of the pressure-sensitive adhesive layer 4 is 5 μm or more, the electromagnetic shielding and heat-dissipating sheet 20 has a sufficiently high bonding strength between the pressure-sensitive adhesive layer 4, the heating element and the metal layer 3, and satisfactory insulation properties. When the average thickness of the adhesive layer 4 is 50 μm or less, the heat of the heating element can be efficiently conducted to the metal layer 3 through the adhesive layer 4.

  The method for applying the adhesive is not particularly limited. Examples thereof include a method using a gravure roll coater, reverse roll coater, kiss roll coater, dip roll coater, bar coater, knife coater, spray coater, comma coater, direct coater and the like.

  The adhesive strength of the adhesive layer 4 is preferably 5 N / 25 mm or more, more preferably 8 N / 25 mm or more, more preferably 10 N / 25 mm or more, with respect to SUS304 measured using a measurement method described later. More preferably it is. When the adhesive strength of the adhesive layer 4 is 5 N / 25 mm or more, the electromagnetic shielding heat radiating sheet 20 has a sufficiently high bonding strength between the adhesive layer 4 and the heating element and the metal layer 3.

"Testing method for adhesive strength"
The adhesive strength of the adhesive layer 4 is determined by the following method.
A PET film (“Lumirror (trademark) S-10” manufactured by Toray Industries, Inc.) having a thickness of 50 μm is used as a base material, and an adhesive layer 4 is formed on the base material to obtain a test laminated sheet. Next, the test laminated sheet is cut into a size of 25 mm in length and 200 mm in width to obtain strip-shaped sheet pieces. Next, a strip-shaped sheet is laminated on the test plate made of SUS304 with the adhesive layer facing the test plate. Thereafter, the test plate and the strip-shaped sheet are joined by reciprocating a 2 kg rubber roller (width: about 50 mm) once on the strip-shaped sheet.

  The joined test plate and strip-shaped sheet are left in an environment of 23 ° C. and humidity 50% RH for 24 hours. Thereafter, according to JIS Z0237, a tensile test in the 180 ° direction is performed at a peeling speed of 300 mm / min, and the adhesive strength (N / 25 mm) of the strip-shaped sheet to the test plate is measured.

  The pressure-sensitive adhesive layer 4 may contain a conductive filler in the pressure-sensitive adhesive in order to electrically connect the metal layer and the adherend. By being electrically conductive, absorbed electromagnetic waves can be released from the metal layer. Although there is no restriction | limiting in particular as a conductive filler which can be used, For example, 1 type, or 2 or more types selected from a metal particle, a metal covering conductive filler, a metal fiber filler, a carbon particle, carbon fiber, etc. are mentioned. Among these, carbon particles, particularly carbon black, is preferable in handling.

  The conductive filler is preferably a powder from the viewpoint of being uniformly dispersed in the adhesive layer 4. As for the particle diameter of the conductive filler, the 50% cumulative mass particle diameter (D50) is preferably 0.1 to 50 μm, and more preferably 1 to 30 μm. The particle diameter of the conductive filler is preferably set as appropriate according to the thickness of the adhesive layer 4. When the cumulative mass 50% particle diameter (D50) is 0.1 to 50 μm, a sufficient contact area between the heat conductive filler contained in the adhesive layer 4 and the heating element and the metal layer 3 is obtained. Heat can be efficiently conducted to the metal layer 3 through the adhesive layer 4.

  When using an electroconductive filler, it is preferable that content to the adhesion layer 4 is 5-60 mass%, and it is more preferable that it is 10-50 mass%. When the content is in the above range, a sufficient contact area between the heat conductive filler contained in the adhesive layer 4 and the heating element and the metal layer 3 is obtained, and the heat of the heating element is transferred to the metal via the adhesive layer 4. It can conduct efficiently to the layer 3.

  The “cumulative mass 50% particle size (D50)” is obtained, for example, by laser diffraction particle size distribution measurement using a laser diffraction particle size distribution measuring device having a trade name “SALD-200VER” manufactured by Shimadzu Corporation.

"Peeling sheet"
The release sheet 5 is not particularly limited. For example, a plastic film whose surface is treated with a release treating agent can be used.

  As the release treatment agent, silicone type, long chain alkyl type, fluorine type and the like can be used. Examples of the plastic film include a polyethylene terephthalate (PET) film.

"Method of manufacturing electromagnetic shielding and heat dissipation sheet"
There is no restriction | limiting in particular about the manufacturing method of the electromagnetic shielding heat radiating sheet 10. For example, the heat shielding layer 10 can be obtained by forming the heat radiation layer 2 on one surface of the metal layer 3 and then laminating the protective layer 1 on the heat radiation layer 2. The electromagnetic shielding heat radiation sheet 10 may be laminated in the order of the protective layer 1, the heat radiation layer 2, and the metal layer 3, and include other layers such as an adhesive layer and a laminate layer between the layers as necessary. But you can.
Further, the electromagnetic shielding and radiating sheet 20 can be obtained by further bonding the adhesive layer 4 to the other surface of the metal layer 3 of the electromagnetic shielding and radiating sheet 10. The obtained electromagnetic shielding heat radiating sheet 20 is until the electromagnetic shielding heat radiating sheet 20 is joined to the heating element by laminating the release sheet 5 on the opposite side of the surface of the adhesive layer 4 bonded to the metal layer 3. Meanwhile, the adhesive layer 4 can be protected by the release sheet 5. The electromagnetic shielding and heat-dissipating sheet 20 may be formed by laminating the protective layer 1, the heat radiation layer 2, the metal layer 3, and the adhesive layer 4 in this order, and an adhesive layer, a laminate layer, or the like between the layers as necessary. Other layers may also be included.

  The electromagnetic shielding and heat radiating sheet preferably has a thermal emissivity of 0.8 to 1, more preferably 0.9 to 1. If the thermal emissivity is 0.8 to 1, sufficient thermal emissivity is obtained.

  The electromagnetic shielding and radiating sheet 10 and the electromagnetic shielding and radiating sheet 20 are excellent in electromagnetic shielding properties. In addition, the electromagnetic shielding and radiating sheet 10 and the electromagnetic shielding and radiating sheet 20 can be easily joined to the heating element, and can efficiently radiate the heat of the heating element. Therefore, the electromagnetic shielding heat radiation sheet 20 can be suitably used as a heat spreader for dissipating heat generated by the heating element. Examples of the heating element include electronic components such as a semiconductor chip, a transistor, a capacitor, and a capacitor, and electrical components such as a battery (battery).

  EXAMPLES Hereinafter, although an Example demonstrates this invention more concretely, this invention is not limited at all by these examples.

(Production of metal sheet with coat layer)
As heat radiation filler, 5 parts by mass of acetylene black (trade name Denka Black HS-100, manufactured by Denki Kagaku Kogyo Co., Ltd.) and ferrite powder (trade name MB23, manufactured by Nippon Heavy Chemical Industry Co., Ltd., Mn-Zn, average) (Particle size 0.75 μm) 8.2 parts by mass, 2.5 parts by mass of glycerylated chitosan as a binder, 2.5 parts by mass of pyromellitic acid as a crosslinking agent, and 90 parts by mass of N-methyl-2-pyrrolidone as a dispersion medium Using a dissolver type stirrer, the mixture was stirred at a rotation speed of 300 rpm for 10 minutes to prepare a slurry. This slurry was applied to one side of an aluminum foil (A1085, thickness 50 μm) using a bar coater and dried at 180 ° C. for 1 minute to produce a sheet made of aluminum coated with magnetic substance-containing carbon. The thickness of the coating layer obtained by coating the slurry on aluminum and drying was 1 μm. The coat layer corresponds to the heat radiation layer, and the aluminum foil corresponds to the metal layer.

(Preparation of adhesive layer)
100 parts by mass of acrylic adhesive (Vinylol PSA SV-6805 solid content 47% manufactured by Showa Denko KK), 1 part by mass of isocyanate-based crosslinking agent (Coronate HX solid content 100% manufactured by Tosoh Corporation), and acetic acid as a solvent for dilution 100 parts by mass of ethyl was mixed to prepare an adhesive composition. Subsequently, it applied with the doctor blade on PET film by which the peeling process was carried out, the solvent was dried, and peeling PET was then covered, and the adhesive sheet was obtained. An adhesive sheet turns into an adhesive layer by making it adhere | attach with the metal layer mentioned later.

<Manufacture of electromagnetic shielding heat dissipation sheet>
(Example A-1)
As a protective layer 1, an adhesive (EX-2022 manufactured by Showa Denko KK) was applied to a 12 μm PET film and dried to a thickness of 1 μm. Subsequently, the protective layer 1 was bonded on the coating layer of the sheet | seat which has the produced heat radiation layer 2 and the metal layer 3, and the laminated sheet in which the protective layer 1, the heat radiation layer 2, and the metal layer 3 were laminated | stacked in order was produced.
Next, among the PET films formed on both sides of the pressure-sensitive adhesive sheet, the pressure-sensitive adhesive sheet having a thickness of 10 μm from which one PET film is peeled is bonded to the metal layer surface of the laminated sheet, thereby having the pressure-sensitive adhesive layer 4 and the release sheet 5. The electromagnetic shielding heat radiation sheet A-1 was obtained.

(Example A-2)
Example A-, except that the magnetic material used in the thermal radiation layer 2 of Example A-1 was changed to ferrite (trade name NFP-NB4, Ni-Zn series, average particle diameter 5 μm, manufactured by Nippon Heavy Chemical Industry Co., Ltd.). In the same manner as for the electromagnetic shielding heat radiation sheet of No. 1, an electromagnetic shielding heat radiation sheet of Example A-2 was obtained.

(Example A-3)
Except not having the adhesion layer 4 of Example A-1, the electromagnetic shielding heat radiation sheet of Example A-3 was obtained in the same manner as the electromagnetic shielding heat radiation sheet of Example A-1.

(Comparative Example B-1)
Except the point which remove | excluded the magnetic body used for the heat radiation layer 2 of Example A-1, it carried out similarly to the electromagnetic shielding heat radiation sheet of Example A-1, and obtained the heat dissipation sheet of Comparative Example B-1.

(Comparative Example B-2)
The electromagnetic shielding sheet of Comparative Example B-2 was obtained in the same manner as the electromagnetic shielding heat dissipation sheet of Example A-1, except that the heat radiation filler used in the heat radiation layer 2 of Example A-1 was omitted. .

(Comparative Example B-3)
Except having changed into the structure except the protective layer 1 of Example A-1, the electromagnetic shielding heat radiation sheet of Comparative Example B-3 was obtained in the same manner as the electromagnetic shielding heat radiation sheet of Example A-1.

  About each of the electromagnetic shielding heat radiation sheet of Examples A-1, A-2, Comparative Examples B-1, B-2, and B-3, the adhesive strength was determined by using the above method. For each of the electromagnetic shielding and heat-dissipating sheets of Examples A-1, A-2 and A-3 and Comparative Examples B-1, B-2 and B-3, the following methods were used to dissipate heat, electromagnetic shielding, and electricity. Insulation was evaluated. The results are shown in Table 1.

(Evaluation of heat dissipation)
60 mm long and 60 mm wide square electromagnetic shielding heat radiation sheet, 60 mm long and 60 mm wide square ceramic heater (WALN-1 manufactured by Sakaguchi Electric Heat Co., Ltd.) on both sides of the protective layer of the electromagnetic shielding sheet Installed. Then, the heater temperature (after 60 minutes) when the ceramic heater was heated at 5 W was measured to evaluate the heat dissipation. Evaluation was performed in an environment of room temperature 25 ° C. and humidity 50% RH.
The heater temperature was 150 ° C. when the ceramic heater without the electromagnetic shielding heat release sheet was heated at 5 W.

(Evaluation of electromagnetic shielding properties)
Electromagnetic shielding properties were evaluated using the KEC method shield property test system of Techno Science Japan Co., Ltd. Measurement was performed at a measurement frequency of 100 kHz to 1 GHz. In general, if the shielding effect is 50 dB or more, it is considered that there is no problem for electromagnetic wave shielding in practical use. For the electromagnetic shielding effect, the average electromagnetic shielding effect in each frequency range for electric and magnetic fields was calculated. Moreover, since the shielding effect in the low frequency range of 0.1 to 1.0 MHz can be expected especially from the electromagnetic shielding effect by the magnetic body, the electromagnetic shielding effect in the range of 0.1 to 1.0 MHz and in the range of 1.0 MHz to 1 GHz. Calculations were made for the electromagnetic shielding effect.

(Evaluation of electrical insulation)
The dielectric breakdown voltage of the electromagnetic shielding heat radiation sheet produced in each example and each comparative example was measured by a method based on JIS C2110-1.
Specifically, a sample obtained by peeling off a peeled PET film of a 100 mm long and 100 mm wide square electromagnetic shielding heat radiation sheet was used as a measurement sample.
For the measurement, a withstand voltage tester (TOS5101) manufactured by Kikusui Electronics Co., Ltd. was used. The upper electrode had a diameter of 25 mm and a height of 25 mm, and the lower electrode had a diameter of 70 mm and a height of 15 mm.
Boosting was performed according to the conditions of the 60-second step-up test of JIS C2110-1, and the voltage at which the sample was broken was defined as the dielectric breakdown voltage.
The obtained results were evaluated as follows.
○: 1 kV or more × less than 1 kV

  Examples A-1 and A-2 showed good results for electrical insulation, heat dissipation, adhesive strength and electromagnetic shielding properties. A-3 did not have an adhesive layer, but showed good results in both electromagnetic shielding and electrical insulation. On the other hand, Comparative Example B-1 having no magnetic material in the heat radiation layer does not provide a sufficient electromagnetic shielding effect at 0.1 to 1.0 MHz for both the electric field and the magnetic field, and the heat radiation filler in the heat radiation layer. Comparative example B-2 which does not have sufficient heat dissipation was not obtained. Further, Comparative Example B-3 having no protective layer did not provide sufficient electrical insulation.

  1: protective layer, 2: heat radiation layer, 3: metal layer, 4: adhesive layer, 5: release sheet, 10, 20: electromagnetic shielding heat dissipation sheet

Claims (13)

It has a protective layer, a heat radiation layer, and a metal layer in order,
The electromagnetic shielding heat radiation sheet, wherein the heat radiation layer contains a heat radiation filler, a magnetic material, and a binder.   The electromagnetic shielding and heat-radiating sheet according to claim 1, wherein the average thickness of the metal layer is 3 to 100 μm.   The electromagnetic shielding heat radiation sheet according to claim 1, wherein the protective layer has an average thickness of 1 to 50 μm.   The average thickness of the said heat radiation layer is 0.1-5 micrometers, The electromagnetic shielding heat radiating sheet as described in any one of Claims 1-3.   The electromagnetic shielding heat radiation sheet according to any one of claims 1 to 4, wherein the heat radiation filler is a carbonaceous material.   The electromagnetic shielding heat dissipation sheet according to any one of claims 1 to 5, wherein the magnetic body is ferrite or a soft magnetic metal.   The electromagnetic shielding heat radiation sheet according to any one of claims 1 to 6, wherein at least one of the binders is one in which at least one of an epoxy resin and a polymer polysaccharide is crosslinked by an acid crosslinking agent.   The electromagnetic shielding heat radiation sheet according to any one of claims 1 to 7, further comprising an adhesive layer on a surface of the metal layer opposite to the heat radiation layer.   The electromagnetic shielding heat radiation sheet according to claim 8, wherein the adhesive layer has an average thickness of 5 to 50 μm.   The electromagnetic shielding heat dissipation sheet according to claim 8 or 9, wherein the adhesive layer contains a conductive filler.   The electromagnetic shielding heat radiation sheet according to any one of claims 8 to 10, further comprising a release sheet on a surface of the adhesive layer opposite to the metal layer.   The electromagnetic shielding heat radiation sheet according to any one of claims 1 to 11, wherein the protective layer is polyethylene terephthalate.   The heat spreader containing the electromagnetic shielding heat-radiation sheet as described in any one of Claims 1-12.

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