KR20170102305A - Insulation sheet, heat spreader and electronic device - Google Patents

Abstract

An insulation sheet according to one aspect of the present invention comprises an insulation layer, a heat radiation layer containing a heat radiation filler and a binder, a metal layer, and a pressure-sensitive adhesive layer in this order, wherein an average thickness of the insulation layer and the pressure- 5 to 50 mu m.

Description

Insulation sheet, heat spreader and electronic device

The present invention relates to an insulating sheet, a heat spreader, and an electronic apparatus. The present application claims priority based on Japanese Patent Application No. 2015-003074 filed on January 9, 2015, the content of which is incorporated herein by reference.

In recent years, electronic components such as semiconductor chips, transistors, capacitors, and capacitors, and electric components such as batteries (batteries) have been made more sophisticated. Along with this, the amount of heat generated by electronic parts and electric parts is increasing. When the temperature of an electronic part or an electric part becomes high, the life may be shortened or the reliability may be deteriorated.

Conventionally, electronic parts and electric parts are provided with a heat sink or a heat spreader for dissipating the heat generated by these parts. As the heat spreader, an adhesive tape is attached to a metal foil having thermal conductivity such as an aluminum foil or a copper foil.

For example, Patent Document 1 discloses a heat-releasing sheet for heat-treatment in which a pressure-sensitive adhesive layer and a heat-radiation sheet having a heat radiation layer formed on a layer containing aluminum or an aluminum alloy are laminated.

Japanese Patent Application Laid-Open No. 2005-101025

However, since the heat radiation layer disclosed in Patent Document 1 is made of aluminum or an aluminum alloy coated with alumina, the alumina layer may be damaged due to impact or deformation. Such defects and the like of the alumina layer inhibit the securing of sufficient insulating property, and therefore, it is difficult to use in a place requiring insulation.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide an insulating sheet which can be easily bonded to a heating element such as an electronic part and which can efficiently diffuse and dissipate heat generated in electronic parts, An object of the present invention is to provide an insulated heat-dissipating sheet capable of coping with the miniaturization and weight reduction and the thinning of parts.

As a result of intensive studies, the inventors of the present invention have found that by having the insulating layer, the heat radiation layer containing the heat radiation filler and the binder, the metal layer, and the adhesive layer in this order and setting the insulating layer and the adhesive layer to a predetermined thickness, Insulating property can be realized.

Formation of a layer on the heat radiation layer may inhibit heat radiation and is not performed in the ordinary skill of the art. However, the inventors of the present invention have found that high thermal diffusivity and insulation can be realized by setting the lamination conditions under predetermined conditions.

Further, it has been found that by providing a predetermined adhesive layer, both the bonding property to the heat generating element and the thermal conductivity to the heat radiation layer can be provided.

That is, the present invention has the following constitution.

(1) A heat-insulating sheet according to one aspect of the present invention includes an insulating layer, a heat radiation layer containing a heat radiation filler and a binder, a metal layer, and an adhesive layer in this order, And a thickness of 5 to 50 mu m, respectively.

(2) In the heat-radiating sheet according to (1), the breakdown voltage is preferably 1 kV or more.

(3) In the heat-radiating sheet described in any one of (1) and (2), the average thickness of the heat radiation layer may be 0.1 to 5 탆.

(4) In the heat-radiating sheet according to any one of (1) to (3), the average thickness of the metal layer may be 20 to 100 탆.

(5) In the heat-radiating sheet according to any one of (1) to (4), the heat radiation filler may be a carbonaceous material.

(6) In the heat-radiating sheet according to any one of (1) to (5), the carbonaceous material may be one or more kinds of materials selected from carbon black, graphite and vapor-grown carbon fiber.

(7) In the heat-radiating sheet according to any one of (1) to (6), at least one kind of the binder, epoxy resin or high-molecular polysaccharide may be crosslinked with an acid crosslinking agent.

(8) The heat-radiating sheet described in any one of (1) to (7) above may contain 20 to 50% by mass of the heat radiation filler and 50 to 80% by mass of the binder.

(9) In the heat-radiating sheet according to any one of (1) to (8), a release sheet may be further provided on the surface of the adhesive layer opposite to the metal layer.

(10) A heat spreader according to an aspect of the present invention includes the heat-radiating sheet according to any one of (1) to (9).

(11) An electronic apparatus according to an aspect of the present invention includes the heat spreader described in (10) above.

INDUSTRIAL APPLICABILITY The insulating sheet according to the present invention can be easily bonded to a heating element such as an electronic part and can efficiently diffuse and dissipate heat generated from electronic parts and the like.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view showing a cross section of an insulating sheet according to an embodiment of the present invention. Fig.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It should be understood, however, by those skilled in the art that the present invention is not limited to the embodiments described below, but may be modified in various ways without departing from the spirit and scope of the present invention. Accordingly, the present invention is not construed as being limited to the description of the embodiments described below.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a schematic view showing a cross section of an insulating sheet according to an embodiment of the present invention; FIG. The insulating sheet 10 shown in Fig. 1 has an insulating layer 1, a heat radiation layer 2 containing a heat radiation filler and a binder, a metal layer 3, and an adhesive layer 4 in this order. The insulating layer 1 and the adhesive layer 4 each have an average thickness of 5 to 50 占 퐉. Prior to use of the heat-radiating sheet 10, the release sheet 5 may be further laminated on the exposed surface of the pressure-sensitive adhesive layer 4 if necessary. Other layers may be provided between the layers.

The " average thickness " refers to a value obtained as an arithmetic average value of the thicknesses of 10 randomly selected portions of the heat-radiating sheet 10 by observing the cross-section thereof.

≪ Insulating layer &

The insulating layer 1 is an outermost layer when the heat-radiating sheet 10 is bonded to a heating element such as an electronic component.

The insulating layer 1 has electrical insulation. Insulation means that insulation can be maintained without causing insulation breakdown even when a voltage of 1 to 5 kV is applied to both surfaces of the insulating layer 1, for example.

Since the insulating layer 1 has an insulating property, it is possible to use the insulating layer 1 even in a place where the insulating property inside the electronic parts is required.

The material constituting the insulating layer 1 is not particularly limited as long as it has an insulating property, and a resin material or a ceramic material can be used. For example, polyesters such as polyethylene terephthalate (PET), polyolefins such as polypropylene and polyethylene, and the like can be used. From the viewpoints of insulation and heat resistance, PET is particularly preferable.

The insulating layer 1 has an average thickness of 5 to 50 占 퐉. The insulating layer 1 preferably has an average thickness of 5 to 15 mu m. When the average thickness of the insulating layer 1 is 5 to 50 占 퐉, sufficient insulating property and high heat radiation property can be maintained.

The method of laminating the insulating layer 1 on the heat radiation layer 2 is not particularly limited. For example, a method of melt-extruding a resin to be the insulating layer 1 and laminating it on a heat radiation layer, or a method of previously laminating the insulating layer 1 formed into a film shape with the heat radiation layer 2 There is a method of joining.

By having the insulating layer 1 as described above, the insulating sheet 10 can maintain high insulation with the outside. As a result, it is possible to use the heat-radiating sheet 10 even in a place where the insulating property of electronic components or the like is required.

The insulating layer 1 can also improve the wear resistance of the heat-radiating sheet 10 to protect the heat radiation layer 2 and the like formed thereunder. That is, even if impact or deformation is applied to the heat-radiating sheet 10, the heat radiation property and the insulation property can be maintained.

≪

The heat radiation layer (2) contains a heat radiation filler and a binder.

The heat radiation filler used for the heat radiation layer 2 is not particularly limited, irrespective of the metal and the base metal, if the emissivity is 0.8 or more. From the viewpoint of high heat 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 these may be selected and used. The particle diameter of the heat radiation filler preferably has a cumulative mass 50% particle diameter (D50) of 0.1 to 2.0 탆, more preferably 0.2 to 1 탆. When the cumulative mass 50% particle diameter (D50) is 0.1 to 2.0 占 퐉, a highly smooth and highly heat-resistant heat radiation layer can be obtained.

The binder used for the heat radiation layer 2 is not particularly limited as long as it is a material capable of binding a heat radiation filler. From the viewpoint of the binding property of the heat radiation filler, the coating composition of the heat radiation filler and the binder, and the coating performance of the heat radiation layer (2), heat or a photocurable resin is preferable as the binder. As the photocurable resin, for example, an epoxy resin, an oxetane resin, a vinyl ether resin, a polysiloxane resin, a vinyl ester resin and a (meth) acrylic resin can be used. Examples of the thermosetting resin include thermosetting resins such as epoxy resins, oxetane resins, polysiloxane resins, unsaturated polyester resins, vinyl ester resins, phenol resins, novolac resins, amino resins, ) Acrylic resins, and high-molecular polysaccharides.

As the curable resin to be used as the binder, an epoxy resin or a polymeric polysaccharide of thermosetting is more preferable from the viewpoints of durability and adhesiveness, and it is preferable to crosslink and cure them with an acid crosslinking agent. 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 or more selected from them may be used . As the polymer polysaccharide, there may be mentioned one kind or two or more kinds selected from chitosan, chitin and derivatives thereof. Examples of the acid crosslinking agent include phthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, trimellitic anhydride, tetrahydrophthalic anhydride, pyromellitic anhydride, dodecylsuccinic anhydride, methylnadic anhydride, benzophenone tetracarboxylic anhydride , And anhydrous butane tetracarboxylic acid, and one or more selected from these can be used.

The content of the heat radiation filler in the heat radiation layer (2) is preferably 20 to 50 mass%, more preferably 30 to 40 mass%. When the content of the heat radiation filler in the heat radiation layer 2 is within this range, the heat radiation property of the heat radiation layer 2 can be approximated to the heat radiation rate of the heat radiation filler alone, and the heat radiation property of the heat radiation layer 2 can be improved . The content of the binder in the heat radiation layer (2) is preferably 50 to 80 mass%, more preferably 60 to 70 mass%. When the content of the binder in the heat radiation layer 2 is within this range, there is an advantage that the heat radiation filler is carried on the substrate.

The method of forming 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 of a heat radiation filler and a binder on the insulating layer 1 or the metal layer 3.

The composition of the heat radiation filler and the binder may be diluted with a solvent as required, applied, dried and further cured to form a heat radiation layer (2).

As a composition coating method of the heat radiating filler and the binder, a gravure coating method capable of forming a uniform thickness thin film is preferable as a coating method.

The average thickness of the heat radiation layer is preferably 0.1 to 5 占 퐉, more preferably 0.5 to 3 占 퐉. When the average thickness of the heat radiation layer is 0.1 to 5 占 퐉, the heat radiation filler amount in the heat radiation layer can be sufficiently secured and sufficient heat radiation property 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 part. The metal layer (3) has high thermal conductivity, so that heat generated in the heating element can be efficiently transferred to the heat radiation layer (2).

As the metal layer 3, gold, silver, copper, iron, nickel, aluminum, an alloy including those metals, or the like can be used. It is preferable that the metal layer 3 is made of a metal having a high thermal conductivity. From the viewpoints of low cost and easiness of processing, it is preferable to use copper, aluminum and alloys containing those metals.

The average thickness of the metal layer 3 is preferably 20 to 100 mu m, more preferably 30 to 80 mu m. When the average thickness of the metal layer 3 is not less than 20 탆, the heat-radiating sheet 10 having excellent heat radiation properties can be obtained and the metal layer 3 in the step of producing the heat- . When the average thickness of the metal layer 3 is 100 占 퐉 or less, the shape conformability of the heat-radiating sheet 10 to the heat-generating body when the heat-radiating sheet 10 is bonded to the heat-generating body can be sufficiently ensured. Therefore, even when the surface of the heating element is a curved surface, the contact area between the heating element and the insulating sheet 10 can be sufficiently secured, so that the heat of the heating element can be efficiently dissipated.

<Adhesive Layer>

The adhesive layer 4 is a layer for bonding the insulating sheet 10 to a heating element such as an electronic apparatus.

The pressure-sensitive adhesive used for the pressure-sensitive adhesive layer 4 is not particularly limited. A silicone-based pressure-sensitive adhesive, an acrylic pressure-sensitive adhesive, a urethane pressure-sensitive adhesive, a rubber-based pressure-sensitive adhesive, or the like can be used. Among them, it is preferable to use an acrylic pressure-sensitive adhesive from the viewpoint of adhesiveness.

The pressure-sensitive adhesive may be a solvent-containing or solvent-free adhesive. For the purpose of enhancing the cohesive force of the pressure-sensitive adhesive, a curing agent according 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 and the like can be used.

The adhesive layer 4 may be formed, for example, by applying a pressure-sensitive adhesive diluted with a solvent to one side of the metal layer 3 or the release sheet 5, followed by drying and thermosetting.

The average thickness of the pressure-sensitive adhesive layer 4 used in the present invention is 5 to 50 占 퐉, preferably 8 to 20 占 퐉. When the average thickness of the adhesive layer 4 is not less than 5 占 퐉, the bonding strength between the adhesive layer 4 and the heating element and the metal layer 3 is sufficiently high, and the insulating sheet 10 can be satisfactorily insulated. If the average thickness of the adhesive layer 4 is 50 m or less, the heat of the heating element can be efficiently conducted to the metal layer 3 through the adhesive layer 4. [

The method of applying the pressure-sensitive adhesive is not particularly limited. Examples of the method include a method using a gravure roll coater, a reverse roll coater, a kiss roll coater, a dip roll coater, a bar coater, a knife coater, a spray coater, a comma coater, a 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, and more preferably 10 N / 25 mm or more, in terms of the adhesive strength to SUS304 measured using a measuring method described below Do. If the adhesive strength of the adhesive layer 4 is 5 N / 25 mm or more, the insulating sheet 10 having a sufficiently high bonding strength between the adhesive layer 4 and the heating element and the metal layer 3 is obtained.

&Quot; Test method of adhesion &quot;

The adhesive force of the adhesive layer 4 is obtained by the following method.

A pressure-sensitive adhesive layer 4 is formed on a base material by using a PET film having a thickness of 50 占 퐉 ("Lumirror (registered trademark) S-10" manufactured by Toray Industries, Inc.) as a base material to obtain a test laminate sheet. Subsequently, the test laminated sheet was cut into a size of 25 mm in length and 100 mm in width to obtain a rectangular sheet. Next, a rectangular sheet is laminated on the test plate including SUS304 with the adhesive layer facing the test plate. Thereafter, the rectangular sheet was passed through a 2-kg rubber roller (width: about 50 mm) one time, and a test sheet and a rectangular sheet were stuck.

The bonded test plates and rectangular sheets were allowed to stand for 24 hours under an environment of 23 ° C and 50% RH. Thereafter, a tensile test in the 180 占 direction was carried out at a peeling speed of 300 mm / min in accordance with JIS Z0237, and the adhesive force (N / 25 mm) of the rectangular sheet to the test plate was measured.

The adhesive layer (4) may contain an insulating thermally conductive filler in the adhesive. The thermally conductive filler may be any material that is insulating and has thermal conductivity. For example, one or two or more kinds of particles selected from metal oxides, metal nitrides and metal hydrates can be mentioned. Examples of the metal oxide include aluminum oxide, magnesium oxide, zinc oxide, titanium dioxide and the like. Examples of the metal nitride include aluminum nitride, boron nitride, silicon nitride and the like. Examples of the metal hydrate include magnesium hydroxide, aluminum hydroxide and the like.

The thermally conductive filler is preferable from the viewpoint that the powder is uniformly dispersed in the adhesive layer 4. The particle diameter of the thermally conductive filler preferably has a cumulative mass 50% particle diameter (D50) of 1 to 50 mu m, more preferably 3 to 30 mu m. The particle diameter of the thermally conductive filler is preferably set appropriately in accordance with the thickness of the adhesive layer 4. When the cumulative mass 50% particle diameter (D50) is 1 to 50 占 퐉, the contact area between the heat conductive filler contained in the adhesive layer 4 and the heating element and the metal layer 3 is sufficiently obtained, Can efficiently conduct to the metal layer (3) through the metal layer (4).

The &quot; cumulative mass 50% particle diameter (D50) &quot; can be measured by laser diffraction particle size distribution measurement using, for example, a laser diffraction particle size distribution measuring device of "SALD- 200V ER" available from Shimadzu Seisakusho Co., .

"Peeling sheet"

The release sheet 5 is not particularly limited. For example, a plastic film whose surface has been treated with a peeling agent can be mentioned.

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

&Quot; Method of manufacturing an insulated heat-radiating sheet &quot;

There is no particular limitation on the manufacturing method of the heat-radiating sheet 10. For example, the heat radiation layer 2 is formed on one side of the metal layer 3, and then the insulating layer 1 is laminated on the heat radiation layer 2. Then, Further, the insulating sheet 10 can be obtained by bonding the adhesive layer 4 to one surface of the metal layer 3. The resultant insulating heat-radiating sheet 10 has a structure in which the release sheet 5 is laminated on the opposite side of the surface of the adhesive layer 4 bonded to the metal layer 3, , The adhesive layer 4 can be protected by the release sheet 5. The heat-radiating sheet 10 may be formed by laminating the insulating layer 1, the heat radiation layer 2, the metal layer 3 and the pressure-sensitive adhesive layer 4 in this order. If necessary, A laminate layer, or the like.

The heat-radiating sheet 10 preferably has a thermal emissivity of 0.8 to 1, more preferably 0.9 to 1. When the thermal emissivity is 0.8 to 1, sufficient heat radiation is obtained.

The heat-radiating sheet 10 preferably has an insulation breakdown voltage of 1 kV or more. More preferably, it is 2 kV or more. When the dielectric breakdown voltage is 1 kV or more, there is no problem in use for the pharmacopoeial use and the device can be used.

The heat-radiating sheet 10 can be easily bonded to the heat-generating body and can efficiently dissipate the heat of the heat-generating body. Therefore, the heat-radiating sheet 10 can be suitably used as a heat spreader for heat-dissipating heat generated in the heat-generating body. Examples of the heating element include electronic components such as semiconductor chips, transistors, capacitors, and capacitors, and electric components such as batteries (batteries). Other examples of the heating elements may include electronic circuit boards, solar panels, lighting devices, display backlights, projectors, LED lights, signals, cellular phones, smart phones, personal computers, tablet PCs, servers, , Amplifiers, various batteries, and camera modules.

Example

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples at all.

(Production of adhesive layer)

100 parts by mass of an acrylic pressure-sensitive adhesive (Vinil (registered trademark) PSA SV-6805 solid content 47%, manufactured by Showa Denko K.K.), 1 part by mass of an isocyanate crosslinking agent (CORONATE (registered trademark) HX solid content 100% And 100 parts by mass of ethyl acetate as a diluent solvent were mixed to prepare a pressure-sensitive adhesive composition. Subsequently, the solvent was dried on a PET film (Toyobo Co., Ltd., E7006, thickness 75 μm) whose surface had been subjected to mold release treatment to a predetermined thickness by a doctor blade, the solvent was dried, To obtain a pressure-sensitive adhesive sheet. This pressure sensitive adhesive sheet becomes a pressure sensitive adhesive layer by adhering to a metal layer to be described later.

&Lt; Preparation of Insulation Heat-Release Sheet &

(Example A-1)

An adhesive (EX-2022, manufactured by Showa Denko KK) was coated and dried to a thickness of 1 mu m on a 12 mu m PET film as the insulating layer 1 and subsequently a carbon coating having a heat radiation layer 2 and a metal layer 3 A laminate sheet in which an insulating layer 1, a heat radiation layer 2, and a metal layer 3 are laminated in this order on a carbon coating layer of an aluminum metal sheet (manufactured by Showa Denko Co., Ltd., carbon coated aluminum foil SDX . The heat radiation layer (2) is obtained by crosslinking carbon black as a heat radiation filler and chitosan derivative as a binder with pyromellitic acid. The average thickness of the heat radiation layer 2 is 1 占 퐉, and the metal layer 3 is an aluminum foil having an average thickness of 50 占 퐉.

Next, an adhesive heat-resistant sheet having a thickness of 10 탆, from which one side surface releasable PET film was removed, was bonded to the metal layer side of the laminate sheet to obtain an insulating heat-releasing sheet A-1.

(Example A-2)

The same procedure as in Example A-1 was repeated except that the insulating layer 1 of Example A-1 was changed to a 50 占 퐉 PET film and the average thickness of the adhesive layer 4 was changed to 50 占 퐉 Thereby obtaining the heat-radiating sheet of Example A-2.

(Example A-3)

The insulating heat-radiating sheet of Example A-3 was obtained in the same manner as in the insulating heat-radiating sheet of Example A-1 except that the insulating layer of Example A-1 was changed to a 12 占 퐉 polyethylene film.

(Example A-4)

<Synthesis of polyurethane>

A 5L four-necked flask equipped with a thermometer, a stirrer, a dropping funnel and a condenser tube equipped with a drying tube was charged with isophorone diisocyanate and polypropylene glycol having a hydroxyl group with a hydroxyl value of 56 mgKOH / g at the terminal thereof, 474.6 g of the former and 3992.4 g of the former (electron: the latter = 15:14) were charged into a separable flask equipped with a stirrer and a stirrer at a flow rate of 2000 rpm (manufactured by Mitsui Kagaku Fine Chemicals, number average molecular weight: 2000 Thereafter, 100 parts by mass of dioctyltin dilaurate was added to the isophorone diisocyanate and D-2000, and the temperature was raised to 70 占 폚 and reacted for 4 hours to obtain a polyurethane having an isocyanato group at the terminal.

Thereafter, 33.0 g of 2-hydroxyethyl acrylate (equivalent to the amount of the isocyanate group of the above-mentioned polyisocyanate at the theoretical end of the polyurethane) was added, followed by reaction at 70 DEG C for 2 hours to obtain a polyurethane having a weight average molecular weight of 70,000 To obtain a polyurethane having an acryloyl group at the end thereof. At this time, after confirming that the absorption peak derived from the isocyanato group disappeared by the IR spectrum, the reaction was terminated. The weight average molecular weight of the polyurethane having the acryloyl group at the terminal thereof was measured by gel permeation chromatography (trade name: "Shodex GPC-101", manufactured by Showa Denko K.K.) under the following conditions: Quot; Shodex &quot; is a registered trademark).

Column: LF-804 (manufactured by Showa Denko K.K.)

Temperature of column: 40 ° C

Sample: 0.2 mass% tetrahydrofuran solution

Flow rate: 1 ml / min

Eluent: tetrahydrofuran

&Lt; Preparation of polyurethane resin composition >

100 parts by mass of the polyurethane thus obtained, 252 parts by mass of 2-ethylhexyl acrylate, 196 parts by mass of isostearyl acrylate, 18 parts by mass of acrylic acid and 10 parts by mass of 2-hydroxyethyl acrylate, And mixed in a flask to obtain a polyurethane resin composition.

&Lt; Preparation of thermally conductive pressure-sensitive adhesive composition >

To 100 parts by mass of the polyurethane resin composition thus obtained, 300 parts by mass of aluminum hydroxide (trade name: H-31, manufactured by Showa Denko K.K.) having a D50 of 18 占 퐉, which is a thermally conductive filler, -Trimethylbenzoyldiphenylphosphine oxide (manufactured by BASF, trade name: LUCIRIN TPO) were mixed at room temperature using a dispenser to prepare a uniform thermally conductive pressure-sensitive adhesive composition.

<Production of thermally conductive filler-containing pressure-sensitive adhesive sheet>

Using the thermally conductive pressure-sensitive adhesive composition thus prepared, a pressure-sensitive adhesive sheet containing a thermally conductive filler was formed by the following method.

The thermally conductive pressure-sensitive adhesive composition was applied to a PET film (200 mm x 200 mm) having a thickness of 75 탆 and having been subjected to the above-described surface modification treatment, so that the film thickness (average thickness after curing) became 50 탆 thick using an applicator. Thereafter, the same surface-releasing PET film was placed on the coating film containing the pressure-sensitive adhesive composition. Subsequently, on one of the peelable PET films, an irradiation distance of 12 cm, a lamp moving speed of 20 m (light output: 160 W / cm, a metal halide lamp: UV irradiator: 4 kW x 1, manufactured by Nihon Denchi Co., / min, and a dose of about 1000 mJ / cm &lt; 2 &gt; to cure the thermally conductive pressure-sensitive adhesive composition.

Through the above steps, a thermally conductive pressure-sensitive adhesive sheet in which a thermally conductive adhesive layer having a thickness of 50 占 퐉 was sandwiched between two peelable PET films was obtained.

Next, the heat-radiating sheet of Example A-4 was obtained in the same manner as the heat-radiating sheet of Example A-1 except that the pressure-sensitive adhesive sheet of Example 1 was changed to a thermally conductive pressure-sensitive adhesive sheet.

(Comparative Example B-1)

Heat-insulating sheet of Comparative Example B-1 was obtained in the same manner as in Example A-1 except that the insulating layer 1 of Example A-1 was omitted.

(Comparative Example B-2)

Heat-insulating sheet of Comparative Example B-2 was obtained in the same manner as in Example A-1 except that the average thickness of the adhesive layer (4) of Example A-1 was changed to 3 탆.

(Comparative Example B-3)

An insulating heat-radiating sheet of Example B-3 was obtained in the same manner as in the insulating heat-radiating sheet of Example A-1, except that the structure was changed to the structure excluding the heat radiation layer (2) of Example A-1.

With respect to each of the heat-radiation insulating sheets of Examples A-1, A-2, A-3, A-4 and Comparative Examples B-1, B-2 and B-3, . Heat insulating properties of the heat-insulating sheets of Examples A-1, A-2, A-3, A-4 and Comparative Examples B-1, B-2 and B- I appreciated. The results are shown in Table 1.

(Measurement of average thickness)

The cross section of each of the insulating heat-dissipating sheets of the examples and comparative examples cut with a cutter was randomly observed at 10 points by an electron micrometer (Millitron 1240 manufactured by Seiko, EM Corporation), and the thickness of each layer excluding the insulating layer was measured , And his arithmetic mean value was obtained. The insulating layer was not measured since a commercially available film having a predetermined thickness was used.

(Evaluation of electric insulation)

The insulation breakdown voltage of the insulated heat-dissipating sheet produced in each of the Examples and Comparative Examples was measured in accordance with JIS C2110-1.

More specifically, a peeled PET film of a square insulation heat-radiating sheet having a length of 100 mm and a width of 100 mm was used as a measurement sample.

An internal voltage tester (TOS5101) manufactured by Kikusui Denshi Kogyo Co., Ltd. was used for the measurement, and the upper electrode was 25 mm in diameter and 25 mm in height, and the lower electrode was 70 mm in diameter and 15 mm in height.

The step-up was performed in accordance with the conditions of the 60-second step-up test in JIS C2110-1, and the breakdown voltage of the sample was taken as the breakdown voltage.

The obtained results were evaluated as follows.

○: 1 kV or more

×: less than 1 kV

(Evaluation of heat dissipation)

The insulating heat-radiating sheet having a length of 60 mm and a width of 60 mm, which had been peeled off from the peelable PET film, was adhered to both surfaces of a ceramic heater (WALN-1, manufactured by Sakaguchi Dentetsu Co., Ltd.) The adhesive layers of the sheets were laminated facing each other. Then, the heater temperature (after 60 minutes) when the ceramic heater was heated to 5 W was measured, and the heat radiation performance was evaluated. The evaluation was carried out in an environment of room temperature of 25 DEG C and humidity of 50% RH.

The heater temperature when the ceramic heater without the heat-radiating sheet was heated to 5 W was 150 占 폚.

Examples A-1, A-2, and A-3 exhibited good electrical insulation, heat radiation, and adhesion. A-4 contained a filler in the adhesive layer, so that the adhesive strength was lowered. However, even if the adhesive layer was as thick as 50 m, no deterioration in the heat radiation property was observed. On the other hand, in Comparative Example B-1 having no insulating layer, good insulating performance was not obtained, and in Comparative Example B-2 in which the thickness of the adhesive layer was insufficient, the adhesive strength was lowered and good electrical insulation was not obtained. Comparative Example B-3 having no heat radiation layer had a poor heat radiation property.

1: insulating layer
2:
3: metal layer
4: Adhesive layer
5: peeling sheet
10: Insulation sheet

Claims (11)

An insulating layer, a heat radiation layer containing a heat radiation filler and a binder, a metal layer, and an adhesive layer in this order,
Wherein the insulating layer and the adhesive layer each have an average thickness of 5 to 50 占 퐉. The heat-insulating sheet according to claim 1, wherein the insulation breakdown voltage is 1 kV or more. The heat-radiating sheet according to any one of claims 1 to 3, wherein the average thickness of the heat radiation layer is 0.1 to 5 占 퐉. The heat-radiating sheet according to any one of claims 1 to 3, wherein the metal layer has an average thickness of 20 to 100 占 퐉. The heat-radiating sheet according to any one of claims 1 to 4, wherein the heat radiation filler is a carbonaceous material. The heat-radiating sheet according to claim 5, wherein the carbonaceous material is one or more materials selected from carbon black, graphite, and vapor-grown carbon fiber. The heat-insulating sheet according to any one of claims 1 to 6, wherein at least one of the binders, the epoxy resin or the polymer polysaccharide, is crosslinked by an acid crosslinking agent. The heat-insulating sheet according to any one of claims 1 to 7, wherein the heat radiation layer contains 20 to 50 mass% of the heat radiation filler and 50 to 80 mass% of the binder. The heat-insulating sheet according to any one of claims 1 to 8, further comprising a release sheet on a surface of the pressure-sensitive adhesive layer opposite to the metal layer. A heat spreader comprising the heat-radiating sheet according to any one of claims 1 to 9. An electronic device incorporating the heat spreader according to claim 10.

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