JP2010093283A - Heat-dissipating sheet for countermeasure against disturbance by electromagnetic wave - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat-dissipating sheet for countermeasure against disturbance by electro-magnetic wave free from damaging conductivity at electric contacts by generating siloxane, and further having appropriate adhesive force. <P>SOLUTION: There is provided the heat-dissipating sheet 3 for the counter-measure against disturbance by the electromagnetic wave, a magnetic-alloy powder with a shape other than that having a thickness of 2 μm or less and an aspect ratio of 10 or more, and a thermally conductive spherical powder, are included in a rubber and/or a thermoplastic elastomer. Further, the sheet includes a 45 to 70 durometer-type E hardness. Further, there is provided the heat-dissipating sheet 3 for the counter-measure against disturbance by the electromagnetic wave, a magnetic-alloy powder with a shape other than that having a thickness of 2 μm or less and an aspect ratio of 10 or more, and a thermally conductive spherical powder, are included in a rubber and/or a thermoplastic elastomer. Further, the sheet includes a 45 to 70 durometer-type E hardness, and a 3 to 10 ball number at a sloped ball-tack testing. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electromagnetic interference countermeasure heat radiating sheet, and more specifically, both heat and electromagnetic waves generated simultaneously in various electronic components, with a high heat radiation function that guides heat to a heat sink, and an electromagnetic interference countermeasure function that attenuates electromagnetic wave intensity, The present invention relates to an electromagnetic interference countermeasure heat-dissipating sheet having excellent flexibility and moderate adhesiveness, and having no contact failure due to siloxane.

In recent years, the problem of cooling semiconductor elements and the like mounted on various electronic and electrical devices typified by computers has attracted attention as an important issue. As a cooling method for a semiconductor element or the like that needs to be cooled, a method is provided in which a fan is attached to a device casing on which the device is mounted, and the air in the device casing is cooled. A method of cooling by attaching a (heat sink) is representative. When a heat sink is attached to a semiconductor element or the like to be cooled (hereinafter referred to as a component to be cooled), sufficient cooling performance cannot be obtained if the thermal connectivity between the component to be cooled and the heat sink is low. In general, simply contacting a heat sink with a component to be cooled often has a contact resistance at that portion that is too large to achieve sufficient cooling. If the component to be cooled and the heat sink are joined by soldering or the like, they can be connected with low thermal resistance.
However, there is often a problem of thermal matching due to a difference in the coefficient of thermal expansion. Specifically, as a heat sink, an aluminum material having excellent thermal conductivity is usually suitably applied, but a semiconductor element that is a component to be cooled often has a significantly smaller thermal expansion coefficient than that. Therefore, the consistency is deteriorated at the joint between the heat sink and the component to be cooled. If it becomes like this, problems, such as generation | occurrence | production of the curvature by the big difference of a thermal expansion coefficient, and generation | occurrence | production of peeling in a junction part will arise.

  In view of this, a method of sandwiching a molded product such as a rubber sheet between the component to be cooled and the heat sink is considered promising. As the material, there are various heat-resistant base resins with various viscosities, and in terms of flexibility, silicone rubber is used as a base, and fillers with high thermal conductivity such as aluminum oxide and boron nitride are mixed. A method has been proposed in which the rubber sheet is interposed between the component to be cooled and the heat sink.

  Furthermore, countermeasures against electromagnetic wave shielding of electronic devices have been performed by suppressing radiation noise by shielding the electromagnetic wave from the casing of the final product with a shielding member. However, in recent years, not only measures against radiation noise emitted from electrical equipment, but also the occurrence of in-machine interference (causing malfunction due to electromagnetic waves confined in the equipment) has increased, and has both electromagnetic wave absorption performance and heat radiation performance. The demand for heat-dissipating sheets for electromagnetic wave interference is increasing. Therefore, a sheet in which magnetic powder is blended in the above-described rubber sheet having heat dissipation performance and electromagnetic wave absorption performance is imparted has been proposed (for example, see Patent Document 1 and Patent Document 2).

The rubber sheet must be used in close contact with the part to be cooled and the heat sink in order to exhibit heat dissipation performance, but the silicone sheet has rubber elasticity even after being used in close contact with the rubber sheet for a long time. It is an excellent material in that there is little decrease in heat dissipation performance. However, silicone rubber may adversely affect the electrical contact portion due to the generation of siloxane (inhibit conductivity), and improvement of this point has been desired.
Further, due to workability at the time of assembly and repair, it has been required to be able to be easily peeled off without being adhered to the parts to be cooled at the time of assembly, and when there is no need for adhesive.

JP 2001-68312 A JP-A-11-335472

An object of the present invention is to provide an electromagnetic interference countermeasure heat radiation sheet that does not have a risk of adversely affecting an electrical contact portion (inhibiting conductivity) due to generation of siloxane of a conventional rubber sheet. It is another object of the present invention to provide a rubber and / or thermoplastic elastomer composition used above.
Another object of the present invention is to provide an electromagnetic interference countermeasure heat-dissipating sheet having an appropriate adhesive force.

The inventors of the present invention have made extensive studies in view of the above-mentioned problems. As a result, a rubber and / or thermoplastic elastomer is used as a base resin, a magnetic alloy powder having a specific shape and a heat conductive powder having a specific shape are used, and a durometer By setting the type E hardness to a specific value, the inventors have invented an electromagnetic interference countermeasure heat-dissipating sheet that has high flexibility while maintaining the electromagnetic interference countermeasure function and has no contact failure problem due to siloxane. Furthermore, the present inventors have invented an electromagnetic interference countermeasure heat-dissipating sheet imparted with an adhesive force having excellent workability by blending an appropriate tackifier.
That is, the present invention
(1) A rubber alloy and / or a thermoplastic elastomer containing a magnetic alloy powder having a shape other than a shape having a thickness of 2 μm or less and an aspect ratio of 10 or more, and a spherical heat conductive powder, and having a durometer type E hardness of 45 to 70 An electromagnetic interference heat dissipation sheet, characterized by being
(2) 200 to 700 parts by mass of the magnetic alloy powder and 500 to 1100 parts by mass of the thermally conductive powder are contained with respect to 100 parts by mass of the rubber and / or the thermoplastic elastomer (1). Electromagnetic wave interference countermeasure heat dissipation sheet as described in paragraph
(3) Durometer type E containing rubber alloy and / or thermoplastic elastomer containing magnetic alloy powder having a shape other than a shape having a thickness of 2 μm or less and an aspect ratio of 10 or more, a spherical heat conductive powder, and a tackifier. An electromagnetic interference countermeasure heat dissipating sheet having a hardness of 45 to 70 and a ball number of 3 to 10 in an inclined ball tack test,
(4) The electromagnetic wave interference heat radiation sheet according to the item (3), wherein the tackifier is a rosin ester resin and / or a terpene resin.
(5) The magnetic alloy powder 200 to 700 parts by mass, the thermal conductive powder 500 to 1100 parts by mass, and the tackifier 10 to 50 parts by mass with respect to 100 parts by mass of the rubber and / or the thermoplastic elastomer. (3) or (4) the electromagnetic radiation countermeasure heat radiation sheet according to item (4),
(6) The electromagnetic interference countermeasure heat radiating sheet according to any one of (1) to (5), further comprising a flame retardant,
(7) The electromagnetic interference prevention heat radiation sheet according to item (6), wherein the flame retardant is a metal hydrate.
(8) The heat radiation according to (6) or (7), wherein 100 to 500 parts by mass of the flame retardant is contained with respect to 100 parts by mass of the rubber and / or the thermoplastic elastomer. Sheet,
(9) The electromagnetic wave interference heat dissipation sheet, wherein the one-side surface layer of the electromagnetic wave interference heat dissipation sheet is a non-adhesive layer having a ball number of 1 or less in an inclined ball tack test,
(10) An electromagnetic interference countermeasure heat radiation sheet characterized by having a reinforcing layer in at least one part,
(11) The electromagnetic interference prevention heat radiation sheet according to any one of (1) to (9), wherein the thickness is 1.5 mm or less,
(12) Contains a rubber and / or thermoplastic elastomer, a magnetic alloy powder having a shape other than a shape having a thickness of 2 μm or less and an aspect ratio of 10 or more, and a spherical heat conductive powder, and has a durometer type E hardness of 45 to 70. A rubber and / or thermoplastic elastomer composition,
(13) Durometer type E containing rubber alloy and / or thermoplastic elastomer containing magnetic alloy powder having a shape other than a shape having a thickness of 2 μm or less and an aspect ratio of 10 or more, a spherical heat conductive powder, and a tackifier. Provided by a rubber and / or thermoplastic elastomer composition characterized by a hardness of 45-70 and a ball number of 3-10 in a tilted ball tack test.
In the present invention, the aspect ratio can be obtained by dividing the average diameter of the fine particle main surface by the average thickness.
In the present invention, “rubber” and “thermoplastic elastomer” do not include silicone rubber and derivatives thereof.

  The electromagnetic interference countermeasure heat-dissipating sheet of the present invention has both a high heat radiation function for guiding heat and an electromagnetic interference countermeasure function for attenuating electromagnetic wave intensity, has excellent flexibility, and is free from contact failure due to siloxane. Moreover, it can also have moderate adhesive force by including a tackifier. Moreover, it can have the outstanding flame retardance by containing a flame retardant. Furthermore, the rubber and / or thermoplastic elastomer composition of the present invention can easily form the above-mentioned heat radiation sheet against electromagnetic interference.

It is drawing explaining the measuring method of the thermal radiation characteristic in an Example.

  In the present invention, a magnetic alloy powder having a shape other than a shape having a thickness of 2 μm or less and an aspect ratio of 10 or more and a spherical heat conductive powder are used for rubber and / or a thermoplastic elastomer, and a durometer type E hardness is set. By using 45 to 70, it is possible to obtain an electromagnetic interference countermeasure heat-dissipating sheet excellent in flexibility while maintaining high electromagnetic interference countermeasure performance.

In the present invention, the durometer type E hardness is the durometer type E hardness defined in JIS K 6253 “Method for testing the hardness of vulcanized rubber and thermoplastic rubber” and represents flexibility (sheet hardness). It becomes an indicator. In the present invention, the durometer type E hardness is 45 to 70, preferably 50 to 65.
If the durometer type E hardness is too high, the contact area between the sheet and the electronic parts such as the CPU and the heat sink becomes very small, and heat is not conducted efficiently from the CPU to the sheet and from the sheet to the heat sink, resulting in heat dissipation characteristics. It will drop greatly. That is, no matter how high the heat transfer medium is, the heat is not conducted unless the medium is in close contact with each other. Therefore, the sheet of the present invention that conducts heat from the CPU or the like to the heat sink must be flexible to obtain a high contact area with both the CPU and the heat sink, and the flexibility is sufficient. Therefore, the durometer type E hardness is 70 or less, preferably 65 or less. However, if the durometer type E hardness is too small, the tensile strength and tear strength of the sheet will be low, and it may be torn or torn during assembly work, making it unsuitable as a product. Is a durometer type E hardness of 45 or more, preferably 50 or more.

Furthermore, in the present invention, from the viewpoint of workability, it adheres to a CPU or the like and a heat sink so that it can be attached at a predetermined position. However, if the position is misaligned, it can be easily removed so that it can be attached again. By adding a tackifier to the demand for the adhesive function, it is possible to impart tackiness to the sheet itself that can satisfy the demand. In this case, the adhesive force is preferably an adhesive force having a ball number in the range of 3 to 10 in the inclined ball tack test of JIS Z 0237 “Adhesive tape / adhesive sheet test method”, and more preferably 4 to 6.
The above workability is effective for the sheet having a predetermined flexibility. That is, when the sheet is too hard, even if a predetermined tackiness is imparted, it cannot be brought into close contact with an electronic component or the like, and as a result, good workability cannot be obtained.
Furthermore, the flame retardance more than UL94 vertical flame retardant test V-2 requested | required of an electronic device can be provided by mix | blending a flame retardant.

Hereinafter, each component of the present invention will be described in detail.
(A) Rubber Preferred examples of the rubber in the present invention include acrylic rubber and ethylene / propylene rubber.
Acrylic rubber is a rubber elastic body obtained by copolymerizing a small amount of monomers having various functional groups with alkyl acrylates such as ethyl acrylate and butyl acrylate as monomer components. As such, 2-chloroethyl vinyl ether, methyl vinyl ketone, acrylic acid, acrylonitrile, butadiene and the like can be used as appropriate. Specifically, Nipol AR (trade name, manufactured by Zeon Corporation), JSR AR (trade name, manufactured by JSR Corporation), Toacron AR (trade name, manufactured by Toupe) and the like can be used. Further, a binary copolymer with ethylene and a ternary copolymer obtained by copolymerizing an unsaturated hydrocarbon having a carboxyl group in the side chain as a monomer can also be used. Specifically, in the case of a binary copolymer, Baymac D or Baymac DLS, and in the case of a ternary copolymer, Baymac G, Baymac HC, Baymac LS, Baymac GLS (trade names, all of which are Mitsui DuPont) Polychemical Co., Ltd.) can be used. As the crosslinking agent, zinc dimethyl / dithiocarbamate, iron dimethyl / dithiocarbamate, ammonium benzoate, triazine, zinc di-n-butyl / dithiocarbamate, isocyanate, butylated melamine and the like can be used as appropriate. As the ethylene-propylene rubber, EPM (ethylene-propylene copolymer rubber) consisting only of ethylene and propylene, and further a terpolymer EPDM (ethylene-propylene terpolymer) obtained by copolymerizing a small amount of non-conjugated diene can be used. . As the non-conjugated diene used in EPDM, those using dicyclopentadiene, 5-engineeridene norbornene, 1,4-hexadiene and the like can be used. Specific examples include JSR EP (trade name, manufactured by JSR Corporation), Keltan (trade name, manufactured by Idemitsu DM Co., Ltd.), and the like.
The rubber used in the present invention is preferably a rubber having a Mooney viscosity ML1 + 4 (100 ° C.) defined by JIS K 6300 and a low viscosity of 40 or less. This is because if the Mooney viscosity is too high, the resulting sheet becomes hard.

(B) Thermoplastic elastomer Preferred thermoplastic elastomers in the present invention include, for example, ethylene (meth) acrylate alkyl copolymer, ethylene vinyl acetate copolymer, ethylene (meth) acrylic acid copolymer, and styrene copolymer. Is mentioned.
Examples of the ethylene (meth) acrylate alkyl copolymer include an ethylene methyl acrylate copolymer, an ethylene ethyl acrylate copolymer, an ethylene methyl methacrylate copolymer, and an ethylene ethyl methacrylate copolymer. Examples of the ethylene (meth) acrylic acid copolymer include an ethylene acrylic acid copolymer and an ethylene methacrylic acid copolymer. Specifically, for example, Everflex (trade name, manufactured by Mitsui DuPont Polychemical Co., Ltd.) and Jyrex (trade name, manufactured by Nippon Polyolefin Co., Ltd.) can be mentioned.
The styrenic copolymer preferably has at least two polymer blocks A mainly composed of vinyl aromatic compounds and at least one polymer block B mainly composed of conjugated diene compounds. Or a mixture thereof obtained by hydrogenation thereof, for example, ABA, BABA, ABBABA A vinyl aromatic compound-conjugated diene compound block copolymer having a structure such as the above, or a hydrogenated product thereof. Specific examples include SBS (styrene / butadiene block copolymer), SIS (styrene / isoprene block copolymer), SEBS (hydrogenated SBS), SEPS (hydrogenated SIS), and the like. Specific examples include Lavalon and Septon (both trade names, manufactured by Mitsubishi Chemical Corporation).
The thermoplastic elastomer of the present invention preferably has a durometer type E hardness of 60 or more. This is because if the durometer type E hardness is too high, the resulting sheet becomes hard.
At least one kind of rubber and / or thermoplastic elastomer is used, and each may be used alone, or a mixture of both may be used. When rubber and a thermoplastic elastomer are mixed and used, the mass ratio of both is rubber: thermoplastic elastomer, and preferably 90:10 to 10:90.

(C) Magnetic alloy powder As the magnetic alloy powder, sendust (Fe-Al-Si alloy), permalloy (Fe-Ni alloy), iron alloys typified by carbonyl iron, etc. are used. However, in the present invention, a magnetic alloy powder having a shape other than the shape in which the average thickness of the fine particles constituting the powder is 2 μm or less and the aspect ratio (average diameter / thickness) is 10 or more is used. When a magnetic powder having an average thickness of fine particles constituting the powder of 2 μm or less and an aspect ratio (average diameter / thickness) of 10 or more is blended, because of such a shape, there is no flexibility and the sheet hardness is low. This is because it may become hard. The magnetic alloy powder of the present invention is not particularly limited as long as the average thickness of fine particles constituting the powder is 2 μm or less and the aspect ratio (average diameter / thickness) is 10 or more. The magnetic alloy powder can be suitably used. Further, the magnetic alloy powder of the present invention may contain fine particles having an average thickness of 2 μm or less and an aspect ratio (average diameter / thickness) of 10 or more as long as the effects of the present invention are not impaired. The fine particles having the shape are preferably 10% or less, more preferably 5% or less, of all fine particles constituting the powder.
The blending amount of the magnetic alloy powder is preferably 200 parts by weight to 700 parts by weight, more preferably 250 parts by weight to 550 parts by weight with respect to 100 parts by weight of the rubber and / or thermoplastic elastomer. If the blending amount of the magnetic alloy powder is too small, the required electromagnetic interference prevention performance may not be obtained, and if it is too large, the sheet hardness will be very hard and the adhesion will be poor, and good heat dissipation characteristics will be obtained. May not be obtained.
The average particle size of the fine particles constituting the magnetic alloy powder is not particularly limited, but is preferably 30 μm to 110 μm.

(D) Thermally conductive powder As the thermally conductive powder, for example, aluminum oxide or magnesium oxide can be used. In the present invention, the shape is a spherical shape including a round shape. In the present invention, the round shape means a shape having no corners such as an ellipse or an egg shape. Thermally conductive powder has a large amount to be added to the sheet so as to give high thermal conductivity. Therefore, when a thermally conductive powder having a shape other than spherical is mixed, the hardness of the sheet may become very hard. In addition, there are cases in which good heat dissipation characteristics cannot be obtained due to a decrease in adhesion to a part to be cooled or a cooling body.
The blending amount of the heat conductive powder is preferably 500 to 1100 parts by mass, more preferably 750 to 950 parts by mass with respect to 100 parts by mass of the rubber and / or the thermoplastic elastomer. If the blending amount is too small, the sheet is soft but the thermal conductivity is low and high heat dissipation characteristics may not be obtained. Moreover, when there are too many compounding quantities, the hardness of a sheet | seat will become hard, and there exists a possibility that heat dissipation may fall as a result.
The average particle size of the fine particles constituting the heat conductive powder is not particularly limited, but is preferably 100 μm or less.

(E) Tackifier In the present invention, a tackifier may be blended. By blending the tackifier, it is possible to impart an appropriate adhesive force necessary for work to the electromagnetic interference prevention heat radiation sheet. Examples of the tackifier include rosin ester resins and terpene resins. Specifically, for example, Superester (trade name, manufactured by Arakawa Chemical Co., Ltd.), YS Polyster (trade name, manufactured by Yasuhara Chemical Co., Ltd.) and the like can be mentioned. A mixture of a rosin ester resin and a terpene resin may be used.
The compounding amount of the tackifier is preferably 10 to 50 parts by mass, more preferably 20 to 30 parts by mass with respect to 100 parts by mass of rubber and / or thermoplastic elastomer. If the blending amount is too small, the prescribed adhesive strength cannot be obtained. If the blending amount is too large, the adhesive strength is too high and the sheet becomes very soft, so handling of the sheet is very difficult to handle. It may become.

(F) Flame Retardant When used in an electronic device or the like that requires flame retardancy according to UL standards or the like, it is desirable to incorporate a flame retardant. Examples of the flame retardant include metal hydrates such as aluminum hydroxide and magnesium hydroxide, phosphorus flame retardants such as phosphoric acid compounds, polyphosphoric acid oxides and red phosphorus compounds, and melamine cyanurate. Among these, it is desirable to use a metal hydrate flame retardant such as aluminum hydroxide or magnesium hydroxide. The blending amount is preferably 100 to 500 parts by mass, more preferably 200 to 400 parts by mass with respect to 100 parts by mass of rubber and / or thermoplastic elastomer. This is because if the amount is too small, the required flame retardancy cannot be obtained, and if the amount is too large, the sheet may become hard.

In the present invention, a plasticizer may be added. As the plasticizer, commonly used plasticizers can be used, and examples thereof include ether / ester, paraffin, and trimet acid derivatives. As a compounding quantity, 50-100 mass parts is preferable with respect to 100 mass parts of rubber | gum and / or a thermoplastic elastomer.
In the present invention, various commonly used additives such as antioxidants, lubricants and the like can be appropriately blended as necessary within a range not impairing the object of the present invention.

Next, the structure of the sheet of the present invention will be described.
(A) Non-adhesive layer The sheet of the present invention preferably imparts an appropriate adhesive force necessary for working as described above by blending a tackifier, but in some cases, a surface to be adhered On the opposite surface, a sheet having no adhesiveness may be required.
In this invention, the non-adhesive layer may be sufficient as the one-side surface layer of the said electromagnetic wave interference countermeasure heat radiating sheet which has adhesiveness. The non-adhesive layer preferably has a ball number of 1 or less in the tilted ball tack test described above, and more preferably less than 1. The means for making the one-side surface layer of the sheet a non-adhesive layer is not particularly limited, and examples thereof include a method of applying a powder such as talc or silica, or applying a thin film or nonwoven fabric.
By using a sheet that has a non-adhesive layer on one side of the heat-dissipating heat-dissipating sheet that has adhesiveness, when attaching the sheet to the target device, stick the adhesive side on the part that you want to dissipate and remove it from the specified position. At the same time, since the other side is a non-adhesive layer, the sheet does not stick to the jigs used for handing or pasting, and it is possible to make a heat dissipation sheet with better operability against electromagnetic interference. It is.
Although there is no limitation in particular in the thickness of a non-adhesion layer, 0.004-0.012 mm is preferable.

(B) Reinforcing layer In the sheet of the present invention, for example, when a sheet having a small thickness is used, the sheet may be torn off when it is peeled off after being attached to a predetermined device or metal plate. It may be easier. In particular, the sheet may be easily broken when the thickness is 0.5 mm or less. For this reason, in this invention, you may have a reinforcement layer in a part of sheet | seat. The reinforcing layer in the present invention is not particularly limited as long as it does not impair the characteristics of the electromagnetic interference prevention heat radiation sheet of the present invention. For example, a thin film, a nonwoven fabric, or a mesh can be used. The reinforcing layer may also serve as the non-adhesive layer.
The thickness of the reinforcing layer is not particularly limited, but is preferably 0.004 to 0.012 mm.
The reinforcing layer in the present invention can be provided by laminating, for example, on one side of the sheet or inside the sheet. By using a heat-dissipating heat-dissipating sheet with a reinforcing layer, it is possible to obtain a heat-dissipating heat-dissipating sheet that is excellent in workability and is easy to tear off even if a thin sheet is used or peeled off again. It is.

(C) Sheet thickness In the present invention, the thickness of the sheet is preferably 1.5 mm or less. If the thickness of the sheet becomes too thick, the distance through which heat is transferred becomes long, which may be disadvantageous particularly for applications that require high heat dissipation characteristics. The thickness of the sheet is more preferably 0.3 to 1.0 mm.

  In another preferred embodiment of the present invention, the rubber and / or the thermoplastic elastomer, the magnetic alloy powder having a shape other than the shape having a thickness of 2 μm or less and an aspect ratio of 10 or more, and the spherical heat It is a rubber and / or thermoplastic elastomer composition containing conductive powder and having a durometer type E hardness of 45 to 70. In this composition, it is also preferable that the ball numbers are 3 to 10 in an inclined ball tack test.

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example, this invention is not limited to this.

In the following Tables 1 to 9, Examples 1 to 11 and 13 and Comparative Examples 1 to 10 are polymers, magnetic powders, heat conductive powders, tackifiers, flame retardants, and plasticizers in the tables. The material was kneaded by each blending part (hereinafter simply referred to as “each material”) and a conventional method, and a sheet having a predetermined thickness (1.5 mm or less) was obtained by extrusion and a rolling mill.
In Example 12, each material was kneaded by a conventional method, the thickness was 1.0 mm by extrusion and rolling, and talc was sprayed over the entire surface, and then uniformly applied while removing the excess amount with a brush. Got.
In Examples 14 to 19, after each material was kneaded and extruded by a conventional method, a sheet was obtained by laminating a polyester film, a nonwoven fabric, or a mesh on one side or inside with a rolling mill. In the case of laminating inside, it was laminated at a position of 0.1 to 0.3 mm from the upper surface in the sheet cross section.
Furthermore, Examples 20-22 knead | mix each material by a conventional method, and after extruding, inside a polyester film, a nonwoven fabric, and a nonwoven fabric with a rolling mill (position in a sheet cross section 0.1-0.3 mm from an upper surface), Alternatively, a mesh was laminated, and then talc was sprayed over one side, and then uniformly applied while removing excess with a brush to obtain a sheet.

The materials used in Examples 1 to 22 and Comparative Examples 1 to 10 are as follows (described as “material name: manufacturer, trade name”). In addition, about the polyester film, the nonwoven fabric, and the mesh, it described according to thickness.
Example 1
Acrylic rubber: Nippon Zeon Co., Ltd., Nipol AR54.
Sendust: Daido Steel Co., Ltd., DAPMSA10.
Aluminum oxide: Showa Denko KK, AS10.
Rosin ester: Arakawa Chemical Co., Ltd., Superester A100.
Aluminum hydroxide: Nippon Light Metal Co., Ltd., B73.
Oil: Asahi Denka Kogyo Co., Ltd., Adeka Sizer RS700.
Example 2
Ethylene / propylene rubber: Mitsui Chemicals, Inc., 4021.
Sendust: Daido Steel Co., Ltd., DAPMSA10.
Aluminum oxide: Showa Denko KK, AS10.
Rosin ester: Arakawa Chemical Co., Ltd., Superester A100.
Aluminum hydroxide: Nippon Light Metal Co., Ltd., B73.
Oil: Idemitsu Kosan Co., Ltd., Diana Process Oil PW-150.
Example 3
Ethylene / acrylic rubber: Mitsui / DuPont Polychemical Co., Ltd., Baymac HVG
.
Sendust: Daido Steel Co., Ltd., DAPMSA10.
Aluminum oxide: Showa Denko KK, AS10.
Rosin ester: Arakawa Chemical Co., Ltd., Superester A100.
Aluminum hydroxide: Nippon Light Metal Co., Ltd., B73.
Oil: Kao Corporation, Trimex N-08
Example 4
EVA (ethylene vinyl acetate copolymer): Mitsui DuPont Polychemical Co., Ltd., EVAFLEX EV45LX.
Sendust: Daido Steel Co., Ltd., DAPMSA10.
Aluminum oxide: Showa Denko KK, AS10.
Rosin ester: Arakawa Chemical Co., Ltd., Superester A100.
Aluminum hydroxide: Nippon Light Metal Co., Ltd., B73.
Oil: Cosmo Oil Bricantz Co., Ltd., Cosmo White P350.
Example 5
SEBS: Mitsubishi Chemical Corporation, Lavalon 320C.
Permalloy: Daido Steel, DAP PC.
Aluminum oxide: Showa Denko KK, AS10.
Terpene resin: Yasuhara Chemical Co., Ltd., YS Polystar T100.
Magnesium hydroxide: Kamishima Chemical Co., Ltd., Magsees 10A.
Oil: Idemitsu Kosan Co., Ltd., Diana Process Oil PW-150.
Example 6
SEPS: Kuraray Co., Ltd., 2063.
Carbonyl iron: Toda Kogyo Co., Ltd., S-1641.
Aluminum oxide: Showa Denko KK, AS10.
Terpene resin: Yasuhara Chemical Co., Ltd., YS Polystar T100.
Magnesium hydroxide: Kamishima Chemical Co., Ltd., Magsees 10A.
Oil: Idemitsu Kosan Co., Ltd., Diana Process Oil PW-150.
-Example 7
Acrylic rubber: Nippon Zeon Co., Ltd., Nipol AR54.
Ethylene / propylene rubber: Mitsui Chemicals, Inc., 4021.
Aluminum oxide: Showa Denko KK, AS10.
Permalloy: Daido Steel, DAP PC.
Rosin ester: Arakawa Chemical Co., Ltd., Superester A100.
Aluminum hydroxide: Nippon Light Metal Co., Ltd., B73.
Oil: Asahi Denka Kogyo Co., Ltd., Adeka Sizer RS700
Example 8
EEA (ethyl ethylene acrylate copolymer): Nippon Polyolefin Co., Ltd., JEREX EEA A4250.
EVA: Mitsui DuPont Polychemical Co., Ltd., Everflex EV45LX.
Carbonyl iron: Toda Kogyo Co., Ltd., S-1641.
Aluminum oxide: Showa Denko KK, AS10.
Terpene resin: Yasuhara Chemical Co., Ltd., YS Polystar T100.
Magnesium hydroxide: Kamishima Chemical Co., Ltd., Magsees 10A.
Oil: Cosmo Oil Bricantz Co., Ltd., Cosmo White P350.
Example 9
Acrylic rubber: Nippon Zeon Co., Ltd., Nipol AR54.
Sendust: Daido Steel Co., Ltd., DAPMSA10.
Aluminum oxide: Showa Denko KK, AS10.
Oil: Asahi Denka Kogyo Co., Ltd., Adeka Sizer RS700
Example 10
Acrylic rubber: Nippon Zeon Co., Ltd., Nipol AR54.
Sendust: Daido Steel Co., Ltd., DAPMSA10.
Aluminum oxide: Showa Denko KK, AS10.
Aluminum hydroxide: Nippon Light Metal Co., Ltd., B73.
Oil: Kao Corporation, Trimex N-08.
Example 11
Acrylic rubber: Nippon Zeon Co., Ltd., Nipol AR54.
Sendust: Daido Steel Co., Ltd., DAPMSA10.
Aluminum oxide: Showa Denko KK, AS10.
Rosin ester: Arakawa Chemical Co., Ltd., Superester A100.
Oil: Asahi Denka Kogyo Co., Ltd., Adeka Sizer RS700.
Examples 12 to 22
Acrylic rubber: Nippon Zeon Co., Ltd., Nipol AR54.
Sendust: Daido Steel Co., Ltd., DAPMSA10.
Aluminum oxide: Showa Denko KK, AS10.
Rosin ester: Arakawa Chemical Co., Ltd., Superester A100.
Aluminum hydroxide: Nippon Light Metal Co., Ltd., B73.
Oil: Asahi Denka Kogyo Co., Ltd., Adeka Sizer RS700.
Talc: Fuji Talc Industrial Co., Ltd., SP-40
Polyester film: Teijin Film Co., Ltd. Tetoron film thickness 5μm
Non-woven fabric: Mitsui Chemicals, Inc. Syntex PS-103 Thickness 0.16mm
Mesh: Unitika Ltd. Glass Fiber C33A1-104V Thickness 0.14mm
Comparative example 1
Acrylic rubber: Nippon Zeon Co., Ltd., Nipol AR54.
Atomized iron: Kawasaki Steel Corporation, KIP MG150D. Thickness 1μm. Aspect ratio 40.
Aluminum oxide: Showa Denko KK, AS10.
Rosin ester: Arakawa Chemical Co., Ltd., Superester A100.
Aluminum hydroxide: Nippon Light Metal Co., Ltd., B73.
Oil: Asahi Denka Kogyo Co., Ltd., Adeka Sizer RS700.
Comparative example 2
Acrylic rubber: Nippon Zeon Co., Ltd., Nipol AR51.
Sendust: Daido Steel Co., Ltd., DAPMSA10.
Aluminum oxide: Showa Denko KK, AS10.
Rosin ester: Arakawa Chemical Co., Ltd., Superester A100.
Aluminum hydroxide: Nippon Light Metal Co., Ltd., B73.
Oil: Kao Corporation, Trimex N-08.
Comparative example 3
EEA: Nippon Unicar Co., Ltd., NUC-6090.
Carbonyl iron: Toda Kogyo Co., Ltd., S-16410.
Aluminum oxide: Showa Denko KK, AS10.
Terpene resin: Yasuhara Chemical Co., Ltd., YS Polystar T100.
Magnesium hydroxide: Kamishima Chemical Co., Ltd., Magsees 10A.
Oil: Cosmo Oil Bricantz Co., Ltd., Cosmo White P350.
Comparative examples 4, 5, 7-10
Acrylic rubber: Nippon Zeon Co., Ltd., Nipol AR54.
Sendust: Daido Steel Co., Ltd., DAPMSA10.
Aluminum oxide: Showa Denko KK, AS10.
Rosin ester: Arakawa Chemical Co., Ltd., Superester A100.
Aluminum hydroxide: Nippon Light Metal Co., Ltd., B73.
Oil: Asahi Denka Kogyo Co., Ltd., Adeka Sizer RS700.
Comparative Example 6
Acrylic rubber: Nippon Zeon Co., Ltd., Nipol AR54.
Sendust: Daido Steel Co., Ltd., DAPMSA10.
Aluminum oxide: Showa Denko KK, A12.
Rosin ester: Arakawa Chemical Co., Ltd., Superester A100.
Aluminum hydroxide: Nippon Light Metal Co., Ltd., B73.
Oil: Kao Corporation, Trimex N-08.

The sheet thus obtained was measured by the following method.
(1) Hardness Durometer type E
The hardness of the sheet was measured by the durometer type E hardness defined in JIS K 6253 “Method for testing hardness of vulcanized rubber and thermoplastic rubber”.
(2) Electromagnetic wave attenuation effect VCCI
Regarding the electromagnetic wave attenuation effect, a VCCI (information processing system) that measures the intensity of electromagnetic waves generated from the device in the anechoic chamber by attaching the sheet prepared in each example to the CPU of an actual electronic device and operating the device. Measurements based on the Voluntary Control Council for Radio Interference, etc.). This time, it is performed by the 3 m method, and the electromagnetic wave intensity is 40 dBuV / m or less from 30 MHz to 230 MHz, and 47 dBuV / m or less from 230 MHz to 1 GHz.
(3) Heat dissipation characteristics / thermal conductivity / heat sink rising temperature For heat dissipation characteristics, the thermal conductivity of the sheet was measured using a thermal conductivity meter manufactured by Kyoto Electronics Industry Co., Ltd. Further, as shown in FIG. 1, in an actual electronic device, the sheet of each example was sandwiched between the CPU and the heat sink, and the temperature rise of the heat sink when the device was operated was measured with a thermocouple. In FIG. 1, 1 is a thermocouple, 2 is a heat sink, 3 is a sheet, and 4 is a CPU. That is, the higher the rising temperature of the heat sink, the more heat is conducted from the CPU and the better the heat dissipation.
(4) Adhesive ball tack ball No.
About adhesiveness, the adhesive force of the sheet | seat was measured with the inclination-type ball tack of JISZ0237 "adhesive tape * adhesive sheet test method".
(5) Flame Retardancy UL94 Vertical V Flame Retardancy Flame retardance was measured by UL94 vertical V flame retardant.
(6) Re-peelability A rectangular sheet having sides of 40 mm and 50 mm was attached to an aluminum plate, a load of 1.3 kg was applied on the sheet and heated at 65 ° C. for 2 hours, and then the sheet was peeled off. At times, it was evaluated whether it could be broken. If there was a tear, it was marked as “easy to tear” in the table below.
The measurement results of the above (1) to (6) of Examples 1 to 22 are shown in Tables 1 to 6, and the measurement results of (1) to (6) of Comparative Examples 1 to 10 are shown in Tables 7 to 9. .

In Tables 1 to 9, the unit of sheet thickness is mm.
In addition, specific trade names of the compounds described in the plasticizer column are trade names respectively indicated as “oil” in the material column used in the above-described Examples.

(Examples 1-12)
As shown in the above table, in Examples 1 to 12 within the scope of the present invention, the hardness of the sheet is 46 to 70 in durometer type E, so that the sheet is highly flexible and has no problem in handling. It is.
In addition, since the thermal conductivity is 2.2 to 2.7 W / mK, the temperature rise of the heat sink is as high as 23 to 28 ° C, and the sheet conducts heat from the CPU to the heat sink and has excellent heat dissipation. I understand that.
Furthermore, in the 3m method VCCI measurement, the electromagnetic wave intensity is below the standard value and the function of attenuating the electromagnetic wave intensity is excellent.
Moreover, in Examples 1-8, 11, and 12, the adhesive force of the sheet itself is the ball No. in the ball tack due to its softness. Is from 3 to 8, and has an adhesive force that adheres to the CPU and heat sink but can be easily peeled off, and has high workability.
Furthermore, in Example 12 therein, talc powder was applied to one surface to obtain a ball no. 1 is formed as a non-adhesive surface.
Furthermore, in Examples 1-8, 10, 12, it turns out that the vertical flame-retardant test result in UL94 is V-0 and is excellent also in a flame retardance.

(Example 13)
In Example 13, since the thickness is 0.4 mm which is equal to or less than 0.5 mm, the heat dissipation characteristics are extremely excellent, but the removability is easily broken.
(Examples 14 to 22)
In Examples 14 to 22, the sheet of Example 13 is provided with a reinforcing layer made of a polyester film, non-woven fabric, or mesh.
In Examples 14 to 16 in which the reinforcing layer is provided on one surface of the sheet and Examples 17 to 22 in which the reinforcing layer is provided inside the sheet, the thickness of the sheet is 0.4 to 0.5 mm. You can see that it cannot be broken.
However, by providing such a thin reinforcing layer, the rising temperature of the heat sink is 20 ° C. to 22 ° C., which is practically usable without any problem, but compared to Examples 1 to 13 without the reinforcing layer. Slightly reduced heat dissipation characteristics.
In Examples 14 to 16, since the reinforcing layer is provided on one side of the sheet, the ball No. in the ball tack is changed. It also serves to form a non-adhesive surface with 0.
Furthermore, in Examples 20 to 22, in addition to providing a reinforcing layer inside the sheet, ball talc of the ball tack was applied by applying talc to one side of the sheet. 1 non-adhesive surface is also formed.

(Comparative Examples 1-10)
Next, a comparative example will be described below.
First, in Comparative Example 1 in which a magnetic powder having a flat shape having a thickness and an aspect ratio outside the scope of the present invention was blended, the hardness of the sheet exceeded 70 in durometer type E hardness and was very high at 80. Since it is hard, the contact area with the CPU and the heat sink is very small, and the heat dissipation function for conducting heat from the CPU to the heat sink is very inferior, and as a result, the rising temperature of the heat sink is as low as 10 ° C.
In addition, the ball tack has a ball number of 1 and the adhesive strength is very small.

  In Comparative Example 2 using a rubber having a Mooney viscosity (ML1 + 4) exceeding 40 ° C. of 40 and Comparative Example 3 using an elastomer having a durometer type E hardness exceeding 60, the durometer type E hardness of the sheet is 70. It becomes very hard beyond. Similarly to the results, it can be seen that the contact area with the CPU and the heat sink is very small and the heat dissipation from conducting heat from the CPU to the heat sink is poor, and the rising temperature of the heat sink is as low as 16 ° C. and 14 ° C. In addition, it can be seen that the ball tack has a ball number of less than 3 and does not have adhesive strength to adhere to the CPU or heat sink.

  Next, in Comparative Example 4 (Comparative Example of Invention of Claim 2) in which the blending amount of the magnetic powder is less than 200 parts by mass, the electromagnetic wave having an intensity exceeding the standard value in the VCCI 3m method is measured and the radiated electromagnetic wave generated from the CPU is measured. It turns out that the effect to attenuate is inferior. Further, in Comparative Example 5 (Comparative Example of Invention of Claim 2) in which the blending amount exceeds 700 parts by mass, since the durometer type E hardness of the sheet exceeds 70 and is very hard, the contact area with the CPU and heat sink Is very small, inferior in heat dissipation to conduct heat from the CPU to the heat sink, the temperature rise of the heat sink is as low as 14 ° C., and the ball number of the ball tack is 2 and the adhesive force is very small.

And the comparative example 6 which mix | blended the heat conductive powder with the compounding amount suitable but the shape is not round shape and the flat plate shape which is not spherical shape, and the comparative example which was round shape but the compounding amount exceeded 1100 mass parts No. 8 (comparative example of the invention of claim 2) has a durometer type E hardness of more than 70 and is very hard. Therefore, the contact area with the CPU and the heat sink is very small, and the heat dissipation property that conducts heat from the CPU to the heat sink is inferior, the heat sink rise temperature is 12 ° C, 14 ° C lower, and the ball tack number 2 is 2 You can see that it is very small.
Further, in Comparative Example 7 (Comparative Example of Invention of Claim 2) whose blending amount is less than 500 parts by mass, since the thermal conductivity of the sheet is as low as 1.5 W / mK, there is flexibility. It can be seen that the heat dissipation from the CPU to the heat sink is inferior in heat dissipation and the temperature rise of the heat sink is as low as 16 ° C.

Furthermore, since Comparative Example 9 in which the tackifier exceeded 50 parts by mass has a very high adhesive force with a ball tack of 12 and the sheet has a durometer type E hardness of less than 45 and is very soft, It can be seen that handling is very bad because it does not peel off from the hand during handling, or the sheet is torn or torn.
Further, in Comparative Example 10 (comparative example of the invention of claim 8) in which the flame retardant exceeds 500 parts by mass, the durometer type E hardness of the sheet exceeds 70, and the adhesion area with the CPU or the heat sink is extremely small. It can be seen that the heat dissipation from the CPU to the heat sink is inferior, the heat sink rises as low as 15 ° C., the ball tack has a ball number of 2, and the adhesive force is very small.

1 Thermoelectric 2 Heat Sink 3 Sheet 4 CPU

Claims (13)

  The rubber and / or thermoplastic elastomer contains a magnetic alloy powder having a shape other than a shape having a thickness of 2 μm or less and an aspect ratio of 10 or more, and a spherical heat conductive powder, and has a durometer type E hardness of 45 to 70. An electromagnetic interference countermeasure heat radiation sheet.   The said rubber | gum and / or the said thermoplastic elastomer 100 mass parts WHEREIN: The said magnetic alloy powder 200-700 mass parts and the said heat conductive powder 500-1100 mass parts were contained. Electromagnetic interference countermeasure heat dissipation sheet.   A rubber alloy and / or a thermoplastic elastomer containing a magnetic alloy powder having a shape other than a shape having a thickness of 2 μm or less and an aspect ratio of 10 or more, a spherical heat conductive powder, and a tackifier, and having a durometer type E hardness of 45 to 45 70 and a ball number 3 to 10 in an inclined ball tack test.   The electromagnetic interference prevention heat radiation sheet according to claim 3, wherein the tackifier is a rosin ester resin and / or a terpene resin.   200 to 700 parts by mass of the magnetic alloy powder, 500 to 1100 parts by mass of the thermal conductive powder, and 10 to 50 parts by mass of the tackifier with respect to 100 parts by mass of the rubber and / or the thermoplastic elastomer. The electromagnetic radiation interference countermeasure heat radiation sheet according to claim 3 or 4, characterized in that.   The electromagnetic interference countermeasure heat radiation sheet according to any one of claims 1 to 5, further comprising a flame retardant.   The electromagnetic interference prevention heat radiation sheet according to claim 6, wherein the flame retardant is a metal hydrate.   The electromagnetic interference prevention heat radiation sheet according to claim 6 or 7, wherein 100 to 500 parts by mass of the flame retardant is contained with respect to 100 parts by mass of the rubber and / or the thermoplastic elastomer.   The electromagnetic wave interference heat radiation sheet according to any one of claims 3 to 8, wherein the one-side surface layer of the electromagnetic wave interference heat radiation sheet is a non-adhesive layer having a ball number of 1 or less in an inclined ball tack test. .   The electromagnetic wave interference heat radiation sheet according to claim 1, further comprising a reinforcing layer in at least one part.   The electromagnetic wave interference countermeasure heat radiation sheet according to any one of claims 1 to 10, wherein the thickness is 1.5 mm or less.   It contains rubber and / or thermoplastic elastomer, a magnetic alloy powder having a shape other than a shape having a thickness of 2 μm or less and an aspect ratio of 10 or more, and a spherical heat conductive powder, and has a durometer type E hardness of 45 to 70 A rubber and / or thermoplastic elastomer composition.   A rubber alloy and / or a thermoplastic elastomer containing a magnetic alloy powder having a shape other than a shape having a thickness of 2 μm or less and an aspect ratio of 10 or more, a spherical heat conductive powder, and a tackifier, and having a durometer type E hardness of 45 to 45 70 and a rubber number and / or a thermoplastic elastomer composition having a ball number of 3 to 10 in an inclined ball tack test.

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