JP6136104B2 - Heat dissipation member, electronic device and battery - Google Patents

Description

  The present invention relates to a heat dissipation member, an electronic device, and a battery.

  A graphite sheet obtained by heat-treating a polymer film is used as a heat conductor because it exhibits excellent heat conductivity (Patent Document 1).

  In recent years, since the amount of heat generated in electronic devices has increased with higher performance and higher functionality, it is required to use a heat conductor that is further excellent in heat dissipation characteristics. As such a heat conductor, it is disclosed that a laminate in which a graphite sheet and a metal plate are bonded with an adhesive is used (Patent Documents 2 to 5).

  Patent Document 3 describes that a rubber-like elastic adhesive or a silicone-based heat conductive adhesive is used as the adhesive, and Patent Document 4 discloses a conductive filler such as silver, gold, or copper. It is described that an adhesive containing is used. Patent Document 5 describes that an acrylic adhesive is used.

Japanese Patent Laid-Open No. 11-21117 JP 2001-144237 A Japanese Patent Laid-Open No. 10-247708 Japanese Patent Laid-Open No. 2004-23066 JP 2009-280433 A

Conventional heat conductors (laminates) sometimes have poor adhesion strength between the graphite sheet and the metal plate.
Also, a layer made of an adhesive (adhesive layer) usually has a low thermal conductivity, and the thermal resistance in the stacking direction of the laminate increases as the thickness of the layer increases. For this reason, it is required to use an adhesive layer that is as thin as possible.

  However, since the adhesive layer described in the above-mentioned patent document is inferior in the adhesive strength between the graphite sheet and the metal plate, it is impossible to obtain a heat conductor that can be used for electronic devices or the like unless the thickness of the adhesive layer is increased. There was a case. This laminated body with a thick adhesive layer has particularly large thermal resistance in the laminating direction of the laminated body and may have poor heat dissipation characteristics.

  This invention is made | formed in view of such a problem, and it aims at providing the heat radiating member which is excellent in the adhesive strength of a metal layer and a graphite layer, and has a thin adhesive layer.

  As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by a heat dissipation member including a laminate in which a metal layer and a graphite layer are laminated via a specific adhesive layer, The present invention has been completed.

[1] including a laminate in which a metal layer and a graphite layer are laminated via an adhesive layer,
The heat radiating member in which this contact bonding layer is formed from the composition containing polyvinyl acetal resin.

  [2] The heat dissipating member according to [1], wherein the composition further includes a thermally conductive filler.

  [3] The heat dissipation member according to [1] or [2], wherein the polyvinyl acetal resin includes the following structural units A, B, and C.

（構成単位Ａ中、Ｒは独立に水素またはアルキルである。）

(In the structural unit A, R is independently hydrogen or alkyl.)

  [4] The heat dissipation member according to [3], wherein the polyvinyl acetal resin further includes the following structural unit D.

（構成単位Ｄ中、Ｒ¹は独立に水素または炭素数１〜５のアルキルである。）

(In the structural unit D, R ¹ is independently hydrogen or alkyl having 1 to 5 carbon atoms.)

  [5] The heat dissipating member according to [3] or [4], wherein R in the structural unit A is hydrogen or alkyl having 1 to 3 carbon atoms.

[6] The heat dissipation member according to any one of [1] to [5], wherein the adhesive layer has a thermal conductivity in the stacking direction of the stacked body of 0.05 to 50 W / m · K.
[7] The heat dissipation member according to any one of [1] to [6], wherein the adhesive layer has a thickness of 0.05 to 10 μm.

  [8] The heat dissipation member according to any one of [2] to [7], wherein the adhesive layer includes 1 to 80% by volume of a heat conductive filler with respect to 100% by volume of the adhesive layer.

[9] Any of [2] to [8], wherein the thermally conductive filler includes at least one powder selected from the group consisting of metal powder, metal oxide powder, metal nitride powder, and metal carbide powder. The heat dissipating member according to any one of the above.
[10] The heat conductive filler includes at least one powder selected from the group consisting of aluminum nitride powder, aluminum oxide powder, zinc oxide powder, magnesium oxide powder, silicon carbide powder, and tungsten carbide powder. ] The heat radiating member of description.
[11] The heat dissipating member according to [9] or [10], wherein an average diameter of the thermally conductive filler is 0.001 to 30 μm.

[12] The heat dissipation member according to any one of [2] to [8], wherein the thermally conductive filler is a filler containing a carbon material.
[13] The heat dissipation member according to [12], wherein the thermally conductive filler includes at least one powder selected from the group consisting of graphite powder, carbon nanotubes, and diamond powder.

  [14] The heat dissipation according to any one of [1] to [13], wherein the thermal conductivity of the graphite layer in a direction substantially perpendicular to the stacking direction of the stacked body is 250 to 2000 W / m · K. Element.

[15] The heat dissipation member according to any one of [1] to [14], wherein the graphite layer has a thickness of 15 to 600 μm.
[16] The heat dissipation member according to any one of [1] to [15], wherein the thickness of the metal layer is 0.01 to 100 times the thickness of the graphite layer.

  [17] The metal layer is a layer containing at least one metal selected from the group consisting of silver, copper, aluminum, nickel, and an alloy containing at least one of these metals. 16] The heat radiating member in any one of.

[18] Any of [1] to [17], wherein the metal layer is a layer containing one kind of metal selected from the group consisting of copper, aluminum, and an alloy containing at least one of these metals. The heat radiating member of description.
[19] The heat dissipation member has at least two metal layers including one or more metals selected from the group consisting of copper, aluminum, and an alloy containing at least one of these metals, The heat dissipation member according to any one of [1] to [18], wherein at least two are different layers.

[20] The heat dissipation member according to any one of [1] to [19], which includes a resin layer on one or both surfaces of the outermost layer of the heat dissipation member.
[21] The heat dissipation member according to [20], wherein the resin layer includes a filler made of an inorganic compound.
[22] At least one resin selected from the group consisting of an acrylic resin, an epoxy resin, an alkyd resin, a urethane resin, and nitrocellulose, alumina, silica, cordierite, mullite, silicon carbide, and magnesium oxide. The heat dissipating member according to [20] or [21], comprising at least one compound selected from the group consisting of:

[23] An electronic device including the heat dissipation member according to any one of [1] to [22].
[24] A battery including the heat dissipation member according to any one of [1] to [22].

ADVANTAGE OF THE INVENTION According to this invention, the thickness of an adhesive layer is thin and the heat radiating member with high adhesive strength of a metal layer and a graphite layer can be provided.
In addition, according to the present invention, it is possible to provide a heat dissipating member that has excellent workability and / or can be bent.
Furthermore, according to the present invention, it is possible to provide a battery, an electronic device, and the like that can be reduced in weight and size.

FIG. 1 is a schematic cross-sectional view showing an example of an electronic device including a heat dissipation member of the present invention. FIG. 2 is a schematic view showing an example of a graphite layer provided with holes. FIG. 3 is a schematic view showing an example of a graphite layer provided with slits. FIG. 4 is a schematic cross-sectional view showing an example of an electronic device including the heat dissipation member of the present invention. FIG. 5 is a schematic cross-sectional view showing an example of LED illumination including the heat dissipation member of the present invention.

≪Heat dissipation material≫
The heat radiating member of the present invention includes a laminate in which a metal layer and a graphite layer are laminated via an adhesive layer, and the adhesive layer is formed from a composition containing a polyvinyl acetal resin.

  In the laminate, since the metal layer and the graphite layer are laminated via the adhesive layer, the heat dissipating member of the present invention including the laminate has high adhesive strength between the metal layer and the graphite layer, and is easy to process. Excellent and bendable.

<Adhesive layer>
The adhesive layer is not particularly limited as long as it is formed from a composition containing a polyvinyl acetal resin. In addition to the resin, depending on the type of the metal layer, etc. It may be formed from a composition containing a conductive filler, an additive and a solvent.
By using such an adhesive layer, it is possible to obtain a heat radiating member that is excellent in adhesive strength between the metal layer and the graphite layer, can be bent, and is excellent in toughness, flexibility, heat resistance, and impact resistance.

[Polyvinyl acetal resin]
The polyvinyl acetal resin is not particularly limited, but is excellent in toughness, heat resistance and impact resistance, and has the following constitution from the viewpoint of obtaining an adhesive layer excellent in adhesion to a metal layer or a graphite layer even if the thickness is thin. A resin containing units A, B and C is preferred.

前記構成単位Ａは、アセタール部位を有する構成単位であって、例えば、連続するポリビニルアルコ−ル鎖単位とアルデヒド（Ｒ−ＣＨＯ）との反応により形成され得る。

The structural unit A is a structural unit having an acetal moiety, and can be formed, for example, by a reaction between a continuous polyvinyl alcohol chain unit and an aldehyde (R-CHO).

  R in the structural unit A is independently hydrogen or alkyl. When R is a bulky group (for example, a hydrocarbon group having a large number of carbon atoms), the softening point of the polyvinyl acetal resin tends to decrease. Further, the polyvinyl acetal resin in which R is a bulky group has high solubility in a solvent, but may be inferior in chemical resistance. Therefore, R is preferably hydrogen or alkyl having 1 to 5 carbons, more preferably hydrogen or alkyl having 1 to 3 carbons from the viewpoint of the toughness of the obtained adhesive layer, and is preferably hydrogen or propyl. More preferably, hydrogen is particularly preferable from the viewpoint of heat resistance.

  In addition to the structural units A to C, the polyvinyl acetal resin preferably includes the following structural unit D from the viewpoint of obtaining an adhesive layer excellent in adhesive strength with a metal layer or a graphite layer.

前記構成単位Ｄ中、Ｒ¹は独立に水素または炭素数１〜５のアルキルであり、好ましく
は水素または炭素数１〜３のアルキルであり、より好ましくは水素である。

In the structural unit D, R ¹ is independently hydrogen or alkyl having 1 to 5 carbon atoms, preferably hydrogen or alkyl having 1 to 3 carbon atoms, more preferably hydrogen.

  The total content of the structural units A, B, C and D in the polyvinyl acetal resin is preferably 80 to 100 mol% with respect to all the structural units of the resin. Other structural units that can be included in the polyvinyl acetal resin include vinyl acetal chain units other than the structural unit A (structural units in which R in the structural unit A is other than hydrogen or alkyl), the following intermolecular acetal units, and the following hemi Examples include acetal units. The content of vinyl acetal chain units other than the structural unit A is preferably less than 5 mol% with respect to all the structural units of the polyvinyl acetal resin.

（前記分子間アセタール単位中のＲは、前記構成単位Ａ中のＲと同義である。）

(R in the intermolecular acetal unit has the same meaning as R in the structural unit A.)

（前記ヘミアセタール単位中のＲは、前記構成単位Ａ中のＲと同義である。）

(R in the hemiacetal unit has the same meaning as R in the structural unit A.)

  In the polyvinyl acetal resin, the structural units A to D may be regularly arranged (block copolymer, alternating copolymer, etc.) or randomly arranged (random copolymer). Random arrangement is preferred.

  Each constituent unit in the polyvinyl acetal resin has a constituent unit A content of 49.9 to 80 mol% and a constituent unit B content of 0.1 to 49.9 mol with respect to all constituent units of the resin. %, The content of the structural unit C is preferably 0.1 to 49.9 mol%, and the content of the structural unit D is preferably 0 to 49.9 mol%. More preferably, with respect to all the structural units of the polyvinyl acetal resin, the content of the structural unit A is 49.9 to 80 mol%, the content of the structural unit B is 1 to 30 mol%, A content rate is 1-30 mol%, and a content rate of the structural unit D is 1-30 mol%.

  In view of obtaining a polyvinyl acetal resin having excellent chemical resistance, flexibility, wear resistance and mechanical strength, the content of the structural unit A is preferably 49.9 mol% or more.

  It is preferable that the content of the structural unit B is 0.1 mol% or more because the solubility of the polyvinyl acetal resin in the solvent is improved. Further, it is preferable that the content of the structural unit B is 49.9 mol% or less because the chemical resistance, flexibility, wear resistance, and mechanical strength of the polyvinyl acetal resin are unlikely to decrease.

  The constituent unit C preferably has a content of 49.9 mol% or less from the viewpoint of the solubility of the polyvinyl acetal resin in the solvent and the adhesion of the resulting adhesive layer to the metal layer and the graphite layer. In the production of the polyvinyl acetal resin, when the polyvinyl alcohol chain is acetalized, the structural unit B and the structural unit C are in an equilibrium relationship, and therefore the content of the structural unit C may be 0.1 mol% or more. preferable.

  It is preferable that the content rate of the structural unit D exists in the said range from the point that the adhesive layer excellent in the adhesive strength with a metal layer or a graphite layer can be obtained.

  The content of each of the structural units A to C in the polyvinyl acetal resin can be measured according to JIS K 6728 or JIS K 6729.

The content rate of the structural unit D in the polyvinyl acetal resin can be measured by the method described below.
The polyvinyl acetal resin is heated at 80 ° C. for 2 hours in a 1 mol / l sodium hydroxide aqueous solution. By this operation, sodium is added to the carboxyl group, and a polymer having —COONa is obtained. Excess sodium hydroxide is extracted from the polymer and then dehydrated and dried. Thereafter, carbonization is performed and atomic absorption analysis is performed, and the amount of sodium added is determined and quantified.

  In addition, when analyzing the content rate of the structural unit B (vinyl acetate chain), since the structural unit D is quantified as a vinyl acetate chain, the structural unit B measured according to JIS K 6728 or JIS K6729 is used. The content rate of the structural unit D determined is subtracted from the content rate, and the content rate of the structural unit B is corrected.

The polyvinyl acetal resin has a weight average molecular weight of preferably 5,000 to 300,000, and more preferably 10,000 to 150,000. Use of a polyvinyl acetal resin having a weight average molecular weight within the above range is preferable because a heat radiating member can be easily produced and a heat radiating member excellent in moldability and bending strength can be obtained.
The weight average molecular weight of the polyvinyl acetal resin may be appropriately selected according to the desired purpose, but the temperature at the time of manufacturing the heat radiating member can be kept low, and a heat radiating member having high thermal conductivity can be obtained. It is more preferable that it is 10000-40000 from the point of being able to do, and it is still more preferable that it is 50,000-150,000 from the point of being able to obtain the heat radiating member with high heat-resistant temperature.

In the present invention, the weight average molecular weight of the polyvinyl acetal resin can be measured by a GPC method. Specific measurement conditions are as follows.
Detector: 830-RI (manufactured by JASCO Corporation)
Oven: NFL-700M manufactured by Nishio
Separation column: Shodex KF-805L x 2 Pump: PU-980 (manufactured by JASCO Corporation)
Temperature: 30 ° C
Carrier: Tetrahydrofuran Standard sample: Polystyrene

The Ostwald viscosity of the polyvinyl acetal resin is preferably 1 to 100 mPa · s. It is preferable to use a polyvinyl acetal resin having an Ostwald viscosity in the above range because a heat radiating member can be easily produced and a heat radiating member having excellent toughness can be obtained.
The Ostwald viscosity can be measured using an Ostwald-Cannon Fenske Viscometer at 20 ° C. using a solution of 5 g of polyvinyl acetal resin dissolved in 100 ml of dichloroethane.

Specific examples of the polyvinyl acetal resin include polyvinyl butyral, polyvinyl formal, polyvinyl acetoacetal, and derivatives thereof. From the viewpoint of adhesion to the graphite layer and heat resistance of the adhesive layer, polyvinyl formal is used. Is preferred.
As said polyvinyl acetal resin, the said resin may be used independently and 2 or more types of resin from which the order of the coupling | bonding of a structural unit, the number of coupling | bonding, etc. differ may be used together.

The polyvinyl acetal resin may be obtained by synthesis or may be a commercially available product.
The method for synthesizing the resin containing the structural units A, B and C is not particularly limited, and examples thereof include a method described in JP-A-2009-298833. In addition, a method for synthesizing the resin including the structural units A, B, C, and D is not particularly limited, and examples thereof include a method described in JP2010-202862A.

  As a commercial item of the said polyvinyl acetal resin, vinylec C, vinylec K (made by JNC Co., Ltd.) etc. are mentioned as polyvinyl formal, Denkabutyral 3000-K (made by Denki Kagaku Kogyo Co., Ltd.) etc. are mentioned as polyvinyl butyral. Is mentioned.

(Thermal conductive filler)
When the adhesive layer contains a thermally conductive filler, the thermal conductivity of the adhesive layer is improved, and in particular, the thermal conductivity in the stacking direction of the laminate is improved.
By using an adhesive layer containing a thermally conductive filler, the thickness of the adhesive layer is thin, heat dissipation characteristics and workability are excellent, the adhesive strength between the metal layer and the graphite layer is high, workability is excellent, and heat dissipation is possible. A member can be provided. In addition, it is possible to provide an electronic device in which heat generated from the heating element is sufficiently removed to reduce weight and size, a battery in which trouble due to heat generation is suppressed even at a high energy density, and the like.

  In the present invention, the “stacking direction of the laminate” refers to, for example, the longitudinal direction in FIG. 1, that is, the metal layer 2, the adhesive layer 3, and the graphite layer 4 of the laminate (heat radiating member) 1. It refers to the direction. Specifically, it refers to the direction from the metal layer 2 toward the adhesive layer 3 and the graphite layer 4, or the direction from the graphite layer 4 toward the adhesive layer 3 and the metal layer 2.

  The heat conductive filler is not particularly limited, but a metal or metal compound-containing filler such as metal powder, metal oxide powder, metal nitride powder, metal hydroxide powder, metal oxynitride powder and metal carbide powder, And fillers containing carbon materials.

As said metal powder, the powder etc. which consist of metals, such as gold | metal | money, silver, copper, aluminum, nickel, and the alloy containing these metals, etc. are mentioned. Examples of the metal oxide powder include aluminum oxide powder, zinc oxide powder, magnesium oxide powder, silicon oxide powder, and silicate powder. Examples of the metal nitride powder include aluminum nitride powder, boron nitride powder, and silicon nitride powder. Examples of the metal hydroxide powder include aluminum hydroxide powder and magnesium hydroxide powder. Examples of the metal oxynitride include aluminum oxynitride powder, and examples of the metal carbide powder include silicon carbide powder and tungsten carbide powder.
Among these, aluminum nitride powder, aluminum oxide powder, zinc oxide powder, magnesium oxide powder, silicon carbide powder and tungsten carbide powder are preferable from the viewpoint of thermal conductivity and availability.

In addition, when using a metal or metal compound containing filler as a pre-heat conductive filler, it is preferable to use the filler containing the same kind of metal as the metal which comprises the said metal layer.
If a metal or metal compound-containing filler different from the metal constituting the metal layer is used as the pre-thermal conductive filler, a local battery may be formed between the metal layer and the filler, and the metal layer or filler may be corroded. .

  The shape of the metal or metal compound-containing filler is not particularly limited, but may be in the form of particles (including spheres and ellipsoids), flat shapes, columnar shapes, needle shapes (including tetrapot shapes and dendritic shapes), and irregular shapes. Can be mentioned. These shapes can be confirmed using a laser diffraction / scattering particle size distribution measuring device or SEM (scanning electron microscope).

As the metal or metal compound-containing filler, it is preferable to use aluminum nitride powder, aluminum oxide powder, and needle-shaped (particularly tetrapot-shaped) zinc oxide powder.
Zinc oxide has a lower thermal conductivity than aluminum nitride, but when a tetrapot-shaped zinc oxide powder is used, a heat radiating member having better heat dissipation characteristics than when using a particulate zinc oxide powder is obtained. Moreover, the occurrence of delamination between the metal layer and the graphite layer can be reduced by the anchor effect by using the tetrapot-shaped zinc oxide powder.
Aluminum oxide has lower thermal conductivity than aluminum nitride and zinc oxide, but is chemically stable and does not react or dissolve in water or acid, so it has high weather resistance. The heat radiating member which has can be obtained.
When aluminum nitride powder is used as the metal or metal compound-containing filler, a heat radiating member having better heat radiating properties can be obtained.

  The average diameter of the primary particles of the metal or metal compound-containing filler may be appropriately selected according to the size of the heat radiating member to be formed, the thickness of the adhesive layer, etc., but the adhesive layer in the stacking direction of the laminate. From the viewpoint of thermal conductivity, etc., it is preferably 0.001 to 30 μm, more preferably 0.01 to 20 μm. The average diameter of the metal or metal compound-containing filler can be confirmed using a laser diffraction / scattering particle size distribution measuring device, SEM (scanning electron microscope) or the like.

  The average diameter of the metal or metal compound-containing filler refers to the diameter of the particles (the length of the major axis in the case of an oval sphere) when the filler is in the form of particles, and when the filler is flat. Means the longest side, and when the filler is columnar, it means the longer of the diameter of the circle (ellipse major axis) or the length of the column, and when the filler is needle-shaped Refers to the length of the needle.

  Examples of the filler containing the carbon material include graphite powder (natural graphite, artificial graphite, expanded graphite, ketjen black), carbon nanotube, diamond powder, carbon fiber, and fullerene. Among these, heat conductivity is excellent. From this point, graphite powder, carbon nanotube, and diamond powder are preferable.

The average diameter of the primary particles of the filler containing the carbon material may be appropriately selected according to the size of the heat radiating member to be formed, the thickness of the adhesive layer, etc., but the adhesive layer in the stacking direction of the laminate From the viewpoint of thermal conductivity, it is preferably 0.001 to 20 μm, more preferably 0.002 to 10 μm. The average diameter of the filler made of the carbon material can be confirmed using a laser diffraction / scattering particle size distribution measuring device, SEM (scanning electron microscope), or the like.
In addition, the average diameter of a carbon nanotube or carbon fiber means the length of a tube or fiber.

The thermally conductive filler may be a commercially available product having an average diameter or shape in a desired range, or a product obtained by pulverizing, classifying, heating, or the like so that the average diameter or shape is in a desired range. It may be used.
In addition, although the average diameter and shape of the said heat conductive filler may change in the manufacture process of the heat radiating member of this invention, what is necessary is just to mix | blend the filler which has the said average diameter and shape with the said composition.

As the heat conductive filler, a commercially available product subjected to a surface treatment such as a dispersion treatment or a waterproof treatment may be used as it is, or a product obtained by removing a surface treating agent from the commercially available product may be used. Moreover, you may use the surface-treated commercial item which is not surface-treated.
In particular, since aluminum nitride and magnesium oxide are easily deteriorated by moisture in the air, it is desirable to use a waterproofed one.

  As said heat conductive filler, the above-mentioned filler may be used independently and 2 or more types may be used together.

The blending amount of the heat conductive filler is preferably 1 to 80% by volume, more preferably 2 to 40% by volume, and further preferably 2 to 30% by volume with respect to 100% by volume of the adhesive layer.
It is preferable that the thermal conductive filler is contained in the adhesive layer in the amount because the thermal conductivity of the adhesive layer is improved while maintaining the adhesiveness.
When the blending amount of the thermally conductive filler is not more than the upper limit of the range, an adhesive layer having high adhesive strength to the metal layer or the graphite layer is obtained, and the blending amount of the thermally conductive filler is not less than the lower limit of the range. Since an adhesive layer having high thermal conductivity is obtained, it is preferable.

〔Additive〕
The additive is not particularly limited as long as the effect of the present invention is not impaired, but is not limited to antioxidants, silane coupling agents, thermosetting resins such as epoxy resins, curing agents, copper damage inhibitors, metal deactivators. , Antirust agents, tackifiers, anti-aging agents, antifoaming agents, antistatic agents, weathering agents and the like.

  For example, when the resin forming the adhesive layer deteriorates due to contact with a metal, the addition of a copper damage inhibitor or a metal deactivator as described in JP-A-5-48265 is preferred, and the thermal conductivity Addition of a silane coupling agent is preferable for improving the adhesion between the filler and the polyvinyl acetal resin, and addition of an epoxy resin is preferable for improving the heat resistance (glass transition temperature) of the adhesive layer.

As the silane coupling agent, a silane coupling agent (trade names S330, S510, S520, S530) manufactured by JNC Corporation is preferable.
The addition amount of the silane coupling agent is preferably 1 to 10 weights with respect to 100 parts by weight of the total amount of the resin contained in the adhesive layer from the viewpoint that the adhesion of the adhesive layer to the metal layer can be improved. Part.

Examples of the epoxy resin include Mitsubishi Chemical Co., Ltd., jER828, jER827, jER806, jER807, jER4004P, jER152, jER154; Daicel Corporation, Celoxide 2021P, Celoxide 3000; 434; manufactured by Nippon Kayaku Co., Ltd., EPPN-201, EOCN-102S, EOCN-103S, EOCN-104S, EOCN-1020, EOCN-1025, EOCN-1027DPPN-503, DPPN-502H, DPPN-501H, NC6000 and EPPN-202; ADEKA Co., Ltd., DD-503; Shin Nippon Rika Co., Ltd., Rikaresin W-100;
The amount of the epoxy resin added is preferably 1 to 49% by weight with respect to 100% by weight of the total amount of the resin contained in the adhesive layer from the viewpoint of increasing the glass transition temperature of the adhesive layer.

  When adding the epoxy resin, it is preferable to add a curing agent. As the curing agent, an amine curing agent, a phenol curing agent, a phenol novolac curing agent, an imidazole curing agent, or the like is preferable.

The polyvinyl acetal resin that constitutes the adhesive layer has long been used for enameled wires, etc., and is a resin that is difficult to deteriorate or deteriorate when it comes into contact with metal. In the case of using in a copper, a copper damage inhibitor and a metal deactivator may be added. As the copper damage inhibitor, ADEKA Corporation, Mark ZS-27, Mark CDA-16; Sanko Chemical Industries, Ltd., SANKO-EPOCLEAN; BASF Corporation, Irganox MD1024; and the like are preferable.
The amount of the copper damage inhibitor added is preferably 0.1 to 100 parts by weight of the total amount of the resin contained in the adhesive layer from the viewpoint of preventing the deterioration of the resin in the part in contact with the metal of the adhesive layer. 3 parts by weight.

〔solvent〕
The solvent is not particularly limited as long as it can dissolve the polyvinyl acetal resin, but is preferably a solvent capable of dispersing a heat conductive filler, methanol, ethanol, n-propanol, iso-propanol, alcohol solvents such as n-butanol, sec-butanol, n-octanol, diacetone alcohol, benzyl alcohol; cellosolv solvents such as methyl cellosolve, ethyl cellosolve, butyl cellosolve; acetone, methyl ethyl ketone, cyclohexanone, cyclopentanone, isophorone, etc. Ketone solvents; amide solvents such as N, N-dimethylacetamide, N, N-dimethylformamide and 1-methyl-2-pyrrolidone; ester solvents such as methyl acetate and ethyl acetate; dioxa Ether solvents such as tetrahydrofuran, chlorinated hydrocarbon solvents such as dichloromethane, methylene chloride and chloroform; aromatic solvents such as toluene and pyridine; dimethyl sulfoxide; acetic acid; terpineol; butyl carbitol; Can be mentioned.
These solvents may be used alone or in combination of two or more.

  The solvent is preferably used in such an amount that the resin concentration in the composition is 3 to 30% by mass, more preferably 5 to 20% by mass, from the viewpoint of ease of manufacturing the heat radiating member and heat radiating characteristics. .

[Physical properties of adhesive layer]
The adhesive layer preferably has a thermal conductivity in the stacking direction of the laminate of 0.05 to 50 W / m · K, more preferably 0.1 to 20 W / m · K.
When the thermal conductivity of the adhesive layer is in the above range, a heat radiating member having excellent heat dissipation and adhesiveness can be obtained.
It is preferable that the thermal conductivity of the adhesive layer is not more than the upper limit of the above range because a heat radiating member having high adhesive strength between the metal layer and the graphite layer and excellent in mechanical strength and durability can be obtained. On the other hand, it is preferable that the thermal conductivity of the adhesive layer is equal to or higher than the lower limit of the above range because a heat radiating member having excellent heat dissipation can be obtained.
The thermal conductivity in the laminating direction of the laminate of the adhesive layer is obtained by a thermal diffusivity obtained from a laser flash or xenon flash thermal diffusivity measuring device, a specific heat obtained from a differential scanning calorimeter (DSC), or an Archimedes method. It can be calculated from the density obtained.

The thickness of the adhesive layer is not particularly limited, and it is preferably as thin as possible from the viewpoint of reducing thermal resistance, and more preferably 0.05, as long as the metal layer and the graphite layer can be bonded to each other. It is 10-10 micrometers, More preferably, it is 0.1-7 micrometers.
In the heat radiating member of the present invention, since the adhesive layer is formed from a composition containing a polyvinyl acetal resin, the metal layer and the graphite layer can be bonded even if the thickness of the adhesive layer is 1 μm or less.

The thickness of the adhesive layer refers to a metal layer or graphite layer in contact with one side of one adhesive layer, and a metal layer or graphite in contact with a surface opposite to the surface in contact with the metal layer or graphite layer of the adhesive layer. Thickness between layers. However, even when a graphite layer as shown in FIGS. 2 and 3 is used, the thickness between the metal layer and / or the graphite layer refers to the thickness of the adhesive layer that can be filled in the holes or slits of the graphite layer. Does not include thickness.
In addition, the thermally conductive filler that can be included in the adhesive layer may be pierced into the graphite layer, but even in this case, the thickness of the adhesive layer should take into account the filler portion pierced into the graphite layer. It means the thickness between the metal layer and / or the graphite layer.

<Metal layer>
The metal layer is laminated in order to improve the heat capacity, mechanical strength, and workability of the discharge member.
The metal layer is preferably a layer containing a metal having excellent thermal conductivity, more preferably a layer containing gold, silver, copper, aluminum, nickel and an alloy containing at least one of these metals. More preferably, a layer containing silver, copper, aluminum, nickel and an alloy containing at least one of these metals is mentioned, and particularly preferably contains copper, aluminum and at least one of these metals And a layer containing one metal selected from the group consisting of alloys.

The alloy may be in any state of a solid solution, a eutectic or an intermetallic compound.
Specific examples of the alloy include phosphor bronze, copper nickel, and duralumin.

  The thickness of the metal layer is not particularly limited and may be appropriately selected in consideration of the use, weight, thermal conductivity, and the like of the obtained discharge member. Preferably, the thickness is 0.01 to 100 times that of the graphite layer. More preferably, the thickness is 0.1 to 10 times. When the thickness of the metal layer is in the above range, a heat dissipation member having excellent heat dissipation characteristics and mechanical strength can be obtained.

<Graphite layer>
The graphite layer has a large thermal conductivity, is light and flexible. By using such a graphite layer, it is possible to obtain a lightweight heat radiating member having excellent heat radiating characteristics.
The graphite layer is not particularly limited as long as it is a layer made of graphite. For example, a layer produced by the method described in JP-A-61-275117 and JP-A-11-21117 may be used. A commercially available product may be used.

  Commercially available products include eGRAF SPREADERSSHIELD SS-1500 (manufactured by GrafTECH International), Graphinity (manufactured by Kaneka Corporation), PGS graphite sheet (manufactured by Panasonic Corporation), etc., as artificial graphite sheets manufactured from synthetic resin sheets. Examples of the natural graphite sheet produced from natural graphite include eGRAF SPREADERSSHIELD SS-500 (manufactured by GrafTECH International).

The thermal conductivity of the graphite layer in a direction substantially perpendicular to the stacking direction of the laminate is preferably 250 to 2000 W / m · K, more preferably 500 to 2000 W / m · K. When the thermal conductivity of the graphite layer is in the above range, it is possible to obtain a heat radiating member excellent in heat radiating property and heat uniformity.
The thermal conductivity of the graphite layer in the direction substantially perpendicular to the stacking direction of the laminate is measured by the laser flash or xenon flash thermal diffusivity measuring device, DSC and Archimedes method, respectively. And it can measure by multiplying these.

  The thickness of the graphite layer is not particularly limited, and is preferably a thick layer, more preferably 15 to 600 μm, and even more preferably 15 to 500 μm, in order to obtain a heat dissipation member having excellent heat dissipation characteristics. Particularly preferably, the thickness is 20 to 300 μm.

<Resin layer>
The heat radiating member of the present invention may have a resin layer on one or both surfaces of the outermost layer in order to prevent oxidation and improve design.
The resin layer is not particularly limited as long as it is a resin-containing layer, and examples of the resin include acrylic resins, epoxy resins, alkyd resins, urethane resins, and nitrocellulose widely used as paints. Among them, a heat resistant resin is desirable.
Examples of commercially available paints containing the resin include heat-resistant paint (Okitsumo Co., Ltd .: heat-resistant paint one-touch).

  The resin layer may include the thermally conductive filler or a filler having a high far-infrared emissivity in order to impart heat dissipation capability by radiation of far-infrared rays from the surface of the heat dissipation member.

  The filler having a high far-infrared emissivity is not particularly limited. For example, minerals such as cordierite and mullite; nitrides such as boron nitride and aluminum nitride; oxides such as silica, alumina, zinc oxide, and magnesium oxide; Desirably, the filler is at least one filler selected from the group consisting of silicon carbide; and graphite.

The type of resin used for the resin layer may be appropriately selected according to the temperature at which the heat dissipating member is used, the method used when forming the resin layer, and the temperature.
Moreover, what is necessary is just to select suitably the filler of high heat conductivity and / or a filler with a high far-infrared emissivity according to the use for which the heat radiating member is used for the kind of filler used for the said resin layer.

<Configuration of heat dissipation member>
The heat dissipating member of the present invention is not particularly limited as long as the laminate is included, and the metal layers and the graphite layers are alternately arranged on the graphite layer of the laminate, or the metal layers and / or the graphite layers are arranged in any order. Alternatively, a laminate in which a plurality of layers are laminated via the adhesive layer may be used.
When a plurality of metal layers, graphite layers, or adhesive layers are used, these layers may be the same layers or different layers, but the same layers are preferably used. Moreover, the thickness of these layers may be the same or different.

The order of lamination may be appropriately selected according to a desired application, and specifically, may be selected in consideration of desired heat dissipation characteristics, design properties, corrosion resistance, and the like.
The number of stacked layers may be appropriately selected according to a desired application. Specifically, the number of stacked layers may be selected in consideration of the size of the heat dissipation member, heat dissipation characteristics, and the like.

In the heat radiating member of the present invention, the outermost layer is preferably a metal layer from the viewpoint of obtaining a heat radiating member having excellent mechanical strength and workability.
Further, when the heat dissipating member of the present invention is used in the mode as shown in FIG. 1, the shape of the layer not far from the heating element 7 (the metal layer 6 in FIG. The area where the surface opposite to the surface in contact with the adhesive layer of the layer farthest from the heating element 7 may be increased by making the shape such as a sword mountain shape or a bellows shape.

  The heat dissipating member of the present invention is excellent in heat dissipating characteristics, mechanical strength, light weight and manufacturability, so that the metal layer 2, the adhesive layer 3, the graphite layer 4, the adhesive layer 5 and the metal as shown in FIG. It is preferable that the layer 6 is the laminate 1 in which the layers 6 are laminated in this order.

In addition, it is a case where it is a case where the heat radiating member containing the laminated body 1 shown in FIG. 1 is manufactured, Comprising: Depending on a desired use, the laminated body with the high adhesive strength of metal layers (2 and 6) through the graphite layer 4 especially. If it is desired to manufacture the adhesive layer 3, the adhesive layers 3 and 5 may be in direct contact with each other. Examples of such a method include a method using a graphite layer 4 ′ provided with holes 8 as shown in FIG. 2 and a graphite layer 4 ″ provided with slits 9 as shown in FIG.
The shape, number and size of the holes and slits may be appropriately selected from the viewpoints of mechanical strength and heat dissipation characteristics of the heat dissipation member.

  When using a graphite layer with holes or slits, for example, compared to the case without holes or slits, the adhesive layer is formed thicker on the metal layer or graphite layer, and the temperature at the time of bonding is set higher. By doing so, the adhesive layer forming component flows into the holes and slits at the time of thermocompression bonding and the holes and slits can be filled with the adhesive layer forming component. Also, the adhesive layer corresponding to the slits or holes of the graphite layer on the metal layer may be formed thick beforehand by a dispenser or the like.

  Further, by using the graphite layer 4 smaller than the metal layers 2 and 6 (the vertical and horizontal lengths of the layers) so that the adhesive layers 3 and 5 are in direct contact, a heat radiating member having high mechanical strength can be obtained. Can be manufactured.

  The resin layer may be directly formed on the metal layer or the graphite layer, or may be formed on the metal layer or the graphite layer via the adhesive layer.

  When the heat radiating member of the present invention is brought into contact with the heating element, it is necessary to attach heat conductive grease or heat conductive double-sided tape to the contact portion. Therefore, the contact portion does not have the resin layer. Is preferred.

<Method of manufacturing heat dissipation member>
In the heat dissipation member of the present invention, the composition is applied to the metal plate forming the metal layer or the graphite plate forming the graphite layer, and after preliminary drying if necessary, the metal plate and the graphite plate are combined with the composition. It can arrange | position so that it may pinch and can manufacture by heating, applying a pressure. Moreover, when manufacturing the said heat radiating member, it is preferable from the point of obtaining the heat radiating member with high adhesive strength of a metal layer and a graphite layer to apply | coat the said composition to both a metal plate and a graphite plate. .

  Before applying the composition, the metal layer should be removed from the surface oxide layer or degreased and cleaned from the standpoint of obtaining a heat dissipation member with high adhesion strength between the metal layer and the graphite layer. The surface of the graphite layer is preferably subjected to easy adhesion treatment by an oxygen plasma apparatus or a strong acid treatment.

  A method for applying the composition to a metal plate or a graphite plate is not particularly limited, but it is preferable to use a wet coating method capable of uniformly coating the composition. Among the wet coating methods, when a thin adhesive layer is formed, a spin coating method capable of forming a simple and uniform film is preferable. When productivity is important, gravure coating, die coating, bar coating, reverse coating, roll coating, slit coating, spray coating, kiss coating, reverse kiss coating, air knife coating, curtain A coating method, a lot coating method and the like are preferable.

The preliminary drying is not particularly limited, and may be performed by allowing to stand at room temperature for about 1 to 7 days, but at a temperature of about 80 to 120 ° C. for about 1 minute to 10 minutes with a hot plate or a drying furnace. It is preferable to heat.
The preliminary drying may be performed in the air, but may be performed in an inert gas atmosphere such as nitrogen or a rare gas, or may be performed under reduced pressure, if desired. In particular, when drying at a high temperature in a short time, it is preferably performed in an inert gas atmosphere.

  The method of heating while applying the pressure is not particularly limited, but the pressure is preferably 0.1 to 30 MPa, the heating temperature is preferably 200 to 250 ° C., and the heating and pressing time is preferably Is 1 minute to 1 hour. Heating may be performed in the air, but may be performed in an inert gas atmosphere such as nitrogen or a rare gas, or may be performed under reduced pressure as desired. In particular, when heating at a high temperature in a short time, it is preferably performed in an inert gas atmosphere or under reduced pressure.

  The heat radiating member having a resin layer on one or both surfaces of the outermost layer is coated with a paint containing resin on one or both surfaces of the metal layer or the graphite layer, which is the outermost layer of the heat radiating member, and is dried if necessary. You may manufacture by making it harden | cure. In addition, a resin film is formed in advance, and the composition is applied to one or both surfaces of the metal layer or the graphite layer, which is the outermost layer of the heat dissipation member, and after preliminary drying as necessary, the resin film is applied to the application surface. It can also be produced by bringing them into contact and applying pressure or heating as necessary.

≪Use of heat dissipation material≫
The heat dissipating member (laminate) of the present invention has a thin adhesive layer that is excellent in adhesive strength between the metal layer and the graphite layer. Further, when the adhesive layer contains a thermally conductive filler, the thermal conductivity in a direction substantially perpendicular to the stacking direction is high, and even if the overall thickness is thin, it is the same as the conventional thick heat sink Or it has more heat dissipation characteristics. In addition, it is excellent in workability such as cutting, drilling and die cutting, and the adhesive force between the metal layer and the graphite layer is strong and can be bent. For this reason, the heat radiating member of this invention can be used for various uses, and is used suitably especially for an electronic device or a battery.
Moreover, the heat radiating member of this invention is suitable also as a heat equalizing plate for preventing the color nonuniformity of a liquid crystal display or organic EL illumination.

  As an example of use of the heat radiating member of the present invention for an electronic device or the like, as shown in FIG. 1 or FIG. 4, the heat radiating member (laminated body) 1 of the present invention is placed in contact with the heating element 7 in the electronic device. And use it.

FIG. 1 is a schematic cross-sectional view showing an example of an electronic device in which the heat dissipating member (laminate) 1 of the present invention is arranged so that the laminating direction of the laminate is substantially perpendicular to the surface of the heating element 7.
By disposing the heat dissipating member 1 of the present invention in this way, heat is diffused in a direction substantially perpendicular (lateral direction) to the stacking direction of the heat dissipating member (laminate), and the temperature rise near the heat source is alleviated. Can do.

FIG. 4 is a schematic cross-sectional view showing an example of an electronic device in which the heat dissipating member 1 as shown in FIG.
By disposing the heat dissipating member 1 of the present invention in this way, heat is diffused in a direction substantially vertical (longitudinal direction) to the stacking direction of the heat dissipating member (laminate), and the temperature rise near the heat source is alleviated. Can do.

  In addition, when arrange | positioning the heat radiating member of this invention as shown in FIG. 4, you may use what cut | disconnected the heat radiating member (laminated body) in the lamination direction of this heat radiating member. When the heat dissipating member of the present invention is arranged as shown in FIG. 4, the heat generated from the heating element 7 can be quickly dissipated (for example, moved to a cooling device), so that the temperature rise of the heating element 7 can be effectively suppressed. be able to.

<Electronic device>
Examples of the electronic device include a chip such as an ASIC (Application Specific Integrated Circuit) used for image processing, television, audio, and the like, a CPU (Central Processing Unit) such as a personal computer and a smartphone, and LED (Light Emitting Diode) illumination. Etc.

[LED lighting]
The LED illumination will be described with reference to FIG. FIG. 5 is a schematic cross-sectional view showing an example of LED lighting arranged so that the heat dissipating member of the present invention is in contact with the back surface of the LED main body via a heat conductive pad. In particular, when an LED having a very large heat generation amount such as an ultra-bright LED is used as the LED body, the use of the heat dissipation member of the present application is effective.

  The LED body that converts electrical energy into light energy generates heat as it is turned on, and this heat needs to be discharged out of the LED body. This heat is transmitted from the LED main body to the heat radiating member of the present invention through the heat conductive pad, and is radiated by the heat radiating member.

〔battery〕
Examples of the battery include a lithium ion secondary battery, a lithium ion capacitor, and a nickel metal hydride battery used in automobiles and mobile phones.

The lithium ion capacitor may be a module in which a plurality of lithium ion capacitor cells are connected in series or in parallel.
In this case, the heat dissipating member of the present invention may be disposed so as to be in contact with a part of the outer surface of the entire module or so as to cover the entire module, and be in contact with a part of the outer surface of each lithium ion capacitor cell. Or may be arranged to cover each cell.

  Hereinafter, the present invention will be described in detail with reference to examples. However, the present invention is not limited to the contents described in the following examples.

The materials used in the examples of the present invention are as follows.
<Adhesive layer resin>
・ "PVF-C1": polyvinyl formal resin, manufactured by JNC Corporation, Vinylec C (trade name)
・ "PVF-C2": polyvinyl formal resin, manufactured by JNC Corporation, Vinylec C (trade name)
・ "PVF-K": polyvinyl formal resin, manufactured by JNC Corporation, Vinylec K (trade name)
・ "PVB": Polyvinyl butyral, Denka Butyral 3000-K (trade name), manufactured by Denki Kagaku Kogyo Co., Ltd.
・ "Epoxy": Epoxy resin, manufactured by Mitsubishi Chemical Corporation, jER828 (trade name)
・ "Terpene phenol": Terpene phenol resin, Yasuhara Chemical Co., Ltd., YSPOLYSTER T160 (trade name)
・ "Acrylic": Acrylic adhesive, manufactured by Shinsei Plastics, Acrylic Dyne B (trade name)

  The structures and physical properties of the “PVF-C1”, “PVF-C2” and “PVF-K” are shown in Table 1 below.

<Solvent>
・ 1-Methyl-2-pyrrolidone: Wako Pure Chemical Industries, Wako Special Grade ・ Cyclopentanone: Wako Pure Chemical Industries, Wako First Grade

<Thermal conductive filler>
-Zinc oxide powder: Panatetra WZ-0511 (trade name, tetrapot shape, average diameter (needle length): about 10 μm), manufactured by Amtec Co., Ltd.
・ Aluminum nitride powder: Aluminum nitride H grade (trade name, particulate, average diameter (Al): 1 μm), manufactured by Tokuyama Corporation
Aluminum oxide powder: Alumina (low soda) AL-47-H (trade name, particulate, average diameter: 2.1 μm), manufactured by Showa Denko KK
・ Nanodiamond powder: manufactured by CARBODEON, BLEND NUEVO (trade name, particulate, average diameter: 0.004 to 0.006 μm)
・ Aluminum powder: manufactured by Nilaco Corporation, aluminum powder (particulate, average diameter: 30 μm)

<Graphite sheet>
• Graphite sheet (artificial graphite): manufactured by GrafTECH International, SS-1500 (trade name), thickness 25 μm, (sheet surface direction thermal conductivity: 1500 W / m · K)
Graphite sheet (artificial graphite): manufactured by GrafTECH International, SS-1500 (trade name), thickness 40 μm, (sheet surface direction thermal conductivity: 1500 W / m · K)
Graphite sheet (natural graphite): manufactured by GrafTECH International, SS-500 (trade name), thickness 76 μm, (thermal conductivity in the sheet surface direction: 500 W / m · K)

・ Graphite sheet with acrylic adhesive (artificial graphite): Sheet made of Kaneka Co., Ltd., with a layer of acrylic adhesive (thickness 12 μm) on one side of a graphic (thickness 25 μm) ・ Silicone adhesive Graphite sheet (artificial graphite): manufactured by Kaneka Co., Ltd., a sheet with a layer of silicone adhesive (thickness 40 μm) on one side of a graphic (25 μm thickness) PGS graphite sheet: manufactured by Panasonic Corporation , EYG-S091203, thickness 25 μm, (sheet surface direction thermal conductivity: 1600 W / m · K)

<Metal plate>
・ Copper plate: Niraco Co., Ltd., thickness 0.1mm
・ Copper plate: Niraco Co., Ltd., thickness 0.2mm
・ Copper plate: Niraco Co., Ltd., thickness 0.4mm
・ Copper foil: Nilaco Co., Ltd., thickness 0.03mm
・ Copper foil: Nilaco Co., Ltd., thickness 0.05mm
-Electrolytic copper foil for printed wiring boards: Mitsui Metal Mining Co., Ltd., thickness 0.012 mm
・ Electrolytic copper foil for printed wiring board: Fukuda Metal Foil Powder Co., Ltd., thickness 0.018 mm
・ Silver foil: Niraco Co., Ltd., thickness 0.03mm
・ Aluminum plate: Aluminum plate, manufactured by Nilaco Corporation, thickness 0.1 mm
・ Aluminum foil: Nilaco Co., Ltd., thickness 0.03mm
・ Aluminum foil: Tokai Aluminum Foil Co., Ltd., thickness 0.02mm
・ Copper nickel alloy (white copper) foil: Niraco Co., Ltd., thickness 0.03mm
・ Phosphor bronze foil: Nilaco Co., Ltd., thickness 0.03mm

<Resin for resin layer>
・ "Heat-resistant paint": Okitsumo Co., Ltd., heat-resistant paint one-touch (trade name)
・ "Epoxy": Epoxy resin, manufactured by Mitsubishi Chemical Corporation, jER828 (trade name)
・ "Clear Lacquer": Clear Lacquer, manufactured by Kansai Paint Co., Ltd., Selva 26 (trade name)
"PMMA": Methyl methacrylate polymer, manufactured by Miwa Laboratory, MA-830-M50 (trade name)

<Filler for resin layer>
-Cordierite powder: Synthetic cordierite SS-1000 (average particle diameter: 1.7 μm), manufactured by Marusu Shaku Goshi Co., Ltd.
Aluminum oxide powder: Alumina (low soda) AL-47-H (trade name, particulate, average diameter: 2.1 μm), manufactured by Showa Denko KK
・ Silicon carbide powder: Silicon carbide, manufactured by Sigma Aldrich, 200-450 mesh ・ Magnesium oxide powder: Magnesium oxide, manufactured by Kanto Chemical Co., Inc., deer special grade

<Evaluation of thermal conductivity>
The thermal diffusivity and thermal conductivity in the direction perpendicular to the plate surface (stacking direction of the laminate) of the obtained heat radiating member were determined as follows. The heat dissipation members obtained in the following Examples 1 to 13 and Comparative Examples 1 to 3 were cut out into a square plate of about 9.8 mm, and both surfaces were coated with carbon spray (manufactured by Nippon Ship Tool Co., Ltd .: DGF), and then NETZSCH The sample was set in a sample holder of an LFA-447 type xenon flash thermal diffusivity measuring device manufactured by the company. After the sample holder reaches 25 ° C. on the set heat dissipation member, irradiate the xenon lamp with a predetermined intensity, measure the time change of the heat radiation intensity from the surface opposite to the lamp irradiation surface of the heat dissipation member, The thermal diffusivity was obtained by analyzing with software. Measurement conditions such as the gain of the detector were automatic, and the analysis was performed on a single-layer plate in order to evaluate the overall thermal properties of the heat dissipation member.

  Furthermore, the specific heat of the heat radiating member (measured by a diamond DSC type input compensation type differential scanning calorimeter, manufactured by Perkin Elmer Co., Ltd.) and specific gravity (manufactured by Alpha Mirage Co., Ltd., MD-300s type electronic hydrometer) And the thermal conductivity was obtained from the equation of thermal conductivity = thermal diffusivity × specific heat × specific gravity. Table 2 shows the thermal diffusivity and thermal conductivity of the heat radiating members obtained in Examples 1 to 13 and Comparative Examples 1 to 3 below.

  In the case of a laminated heat dissipation member, the heat conduction in the direction substantially perpendicular to the stacking direction of the laminate is governed by the ratio of the layer having a high thermal conductivity, so it is not greatly affected by the method of manufacturing the heat dissipation member, Performance almost as designed can be obtained. Conversely, the reduction of the thermal resistance in the stacking direction of the laminate at the interface of each layer depends largely on the thermal resistance of the interface of each layer and the thermal resistance of the adhesive layer, and is preferably reduced. That is, it can be said that the higher the thermal conductivity in the stacking direction of the laminate, the better the adhesion between the metal layer and the graphite layer, that is, a high-performance heat dissipation member.

<Evaluation of heat dissipation characteristics>
A heat resistant paint (Okitsumo Co., Ltd .: heat resistant paint one-touch) was sprayed on one side of the heat dissipation member obtained in Examples 14 to 37 below so that the thickness of the coating film was about 20 μm and dried. Using a double-sided tape (Sumitomo 3M Co., Ltd., heat conductive adhesive transfer tape No. 9885), the heat-resistant paint unpainted surface side of the heat radiating member and the T0220 package transistor (Toshiba Corporation: 2SD2013) are used. Pasted together. A K thermocouple (Rika Kogyo Co., Ltd. ST-50) is attached to the back of the surface where the heat radiating member of the transistor is bonded, and using a temperature data logger (GL220 made by Graphtec Co., Ltd.) The temperature of the surface opposite to the surface where the heat dissipation member of the transistor is bonded can be recorded. The transistor to which this thermocouple was attached was left in the center of a constant temperature bath set at 40 ° C., and after confirming that the temperature of the transistor became constant at 40 ° C., a 1.0 V power supply was used for the transistor using a DC stabilized power supply. Was applied, and the temperature change of the surface was measured. The temperature of the transistor after 1000 seconds or 3000 seconds after voltage application was measured. The results are shown in Table 3 or 4.

  Since the transistor generates a certain amount of heat if the same wattage is applied, the temperature decreases as the heat dissipation effect of the attached heat dissipation member increases. In other words, it can be said that the heat dissipation member having a lower temperature of the transistor has a higher heat dissipation effect.

  As Comparative Examples 9 to 11, 1000 seconds after voltage application and 3000 seconds, except that copper plates having thicknesses of 0.2 mm, 0.4 mm, and 0.05 mm were used instead of the heat radiating member, respectively. The temperature of the later transistor was measured. The results are shown in Table 3.

<Evaluation of adhesiveness>
The adhesive strength between the metal layer and the graphite layer of the heat radiating member obtained in Examples 1 to 25 and Comparative Examples 1 to 8 has a characteristic that the graphite layer is cleaved (peeled within the layer). It is difficult to obtain numerical values such as tensile load. Therefore, the metal part of the heat radiating member produced in the Example was peeled off, and the state of the inner surface of the metal layer was visually observed for evaluation. When the entire surface of the peeled metal layer is covered with cleaved graphite, ◎, when the metal layer or the adhesive layer appears slightly, ○, more than 1/4 the metal layer or adhesive layer appears A sample was marked with Δ, and a sample with little or no graphite remaining was marked with ×. The results are shown in Table 2 or 3.

[Example 1]
80 g of 1-methyl-2-pyrrolidone (NMP) was put into a 200 ml three-necked flask, a stirring blade made of fluororesin was set from the top, and the stirring blade was rotated by a motor. The number of rotations was adjusted as appropriate according to the viscosity of the solution. 10 g of polyvinyl formal resin (PVF-C1) was charged into the flask using a glass funnel. After the PVF-C1 adhering to the funnel was washed away with 20 g of NMP, the funnel was removed and a glass stopper was attached. The obtained solution was heated with stirring in a water bath set at 80 ° C. for 4 hours to completely dissolve PVF-C1 in NMP. Remove the stirred flask from the water bath and return to room temperature, and then add 10 g of zinc oxide powder as a thermally conductive filler using a dry funnel and stir overnight to obtain an adhesive (composition). It was.

  This adhesive is applied to a copper plate having a size of 50 mm × 50 mm and a thickness of 0.1 mm using a spin coater (Mikasa Co., Ltd .: 1H-D3 type) so that the thickness of the obtained adhesive layer is 4 μm. After coating at a rate of / min, it was pre-dried at 80 ° C. for 3 minutes on a hot plate set at 80 ° C. to obtain a copper plate with an adhesive coating film. In addition, when apply | coating an adhesive agent to a copper plate, the adhesive agent was extract | collected and apply | coated so that the big secondary particle which settled at the bottom part of a flask might not be apply | coated.

  A small heating press (made by Imoto Seisakusho: IMC-) is sandwiched between two copper plates with this adhesive coating, with a 25 μm-thick graphite sheet (SS-1500) previously cut into 50 mm x 50 mm with the adhesive coating on the inside. 19EC type small heating manual press). The adhesive coating film was degassed by repeating pressurization and depressurization several times, taking care not to shift the two copper plates and the graphite sheet, and then pressurized until 6 MPa. Thereafter, the hot plate was heated to 220 ° C. with a heater, and the temperature and pressure were maintained for 30 minutes. After 30 minutes, the heater was turned off while maintaining the pressure, and naturally cooled to about 50 ° C. After cooling, the pressure was released to obtain a heat radiating member. In addition, 1/2 of the value which deducted the thickness of two metal plates and the thickness of a graphite sheet from the thickness of the whole heat radiating member was made into the thickness of an adhesive layer. The thickness of the heat radiating member was measured by Digimatic Indicator ID-C112CXB manufactured by Mitutoyo Corporation.

[Comparative Example 1]
In Example 1, instead of a copper plate with an adhesive coating film, a heat conductive adhesive transfer tape No. manufactured by Sumitomo 3M Limited was used. A heat radiating member was obtained in the same manner as in Example 1 except that a copper plate pasted with 9882 (thickness 50 μm) was used.

[Examples 2 to 11, 13 to 15, 17 to 24, and Comparative Examples 4 to 8]
In Example 1, the types and thicknesses of the metal plate and the graphite sheet were changed as shown in Tables 2 to 3, and the types of resin, the types (presence / absence) and contents of the thermally conductive fillers were changed to Tables 2 to 3. A heat radiating member was obtained in the same manner as in Example 1 except that the adhesive changed as shown was used and the thickness of the adhesive layer was changed as shown in Tables 2-3.

In the following table, when the value obtained by subtracting the thickness of the two metal plates and the thickness of the graphite sheet from the thickness of the heat radiating member measured by Digimatic Indicator ID-C112CXB manufactured by Mitutoyo Corporation is less than 1, Write below the measurement limit.
In addition, in the heat radiating member obtained in Example 9, when the cross section of this heat radiating member was observed with the scanning electron microscope, the thickness of the contact bonding layer was about 0.3-0.5 micrometer although there were variations in places.

[Example 12]
In Example 1, using the adhesive whose type and content of the heat conductive filler were changed as shown in Table 2, the size of the adhesive layer was 1 μm by the same method as in Example 1. It apply | coated on the copper plate of 50 mm x 50 mm and thickness 0.2mm, The copper plate with an adhesive coating film was obtained by the method similar to Example 1. FIG.

  This copper plate with an adhesive coating is placed so that the adhesive coating touches a graphite sheet (SS-1500) with a thickness of 25 μm, and a hot plate of a small heating press (manufactured by Imoto Seisakusho: IMC-19EC type small heating manual press) Left on top. Care was taken so that the copper plate and the graphite sheet do not deviate, and after pressurizing and depressurizing several times, the adhesive coating film was degassed and then pressurized, and kept at room temperature and 6 MPa for 120 minutes to obtain a heat dissipation member .

  The thickness of the adhesive layer was a value obtained by subtracting the thickness of the metal plate and the thickness of the graphite sheet from the thickness of the entire heat dissipation member. The thickness of the heat radiating member was measured by Digimatic Indicator ID-C112CXB manufactured by Mitutoyo Corporation.

[Comparative Examples 2 and 3]
In Example 12, instead of the adhesive and the graphite sheet (SS-1500), a graphite sheet with an acrylic pressure-sensitive adhesive or a graphite sheet with a silicone-based pressure-sensitive adhesive was used. A heat radiating member was obtained in the same manner as in Example 12 except that it was disposed so as to be in contact with the adhesive of the graphite sheet with the agent. Further, the thickness of the adhesive layer was measured in the same manner as in Example 12.

[Example 16]
In Example 1, an adhesive was prepared in the same manner as in Example 1 except that the content of the thermally conductive filler was changed as shown in Table 3.
By applying this adhesive to a single side of a 25 μm thick graphite sheet (SS-1500) so that the thickness of the adhesive layer is 1 μm, it is applied in the same manner as in Example 1 and pre-dried. A graphite sheet with an adhesive coating was obtained.

  This graphite sheet with an adhesive coating film is arranged so that the adhesive coating film is in contact with a graphite sheet (SS-1500) having a thickness of 25 μm, and heat of a small heating press (manufactured by Imoto Seisakusho: IMC-19EC type small heating manual press). Placed on a plate. Careful so that the two graphite sheets do not shift, pressurize and depressurize several times to degas the adhesive coating, and then pressurize and hold at room temperature and 6 MPa for 120 minutes. A laminate in which graphite sheets were laminated was obtained.

In Example 1, the heat radiating member was obtained like Example 1 except having used the obtained laminated body instead of the graphite sheet. That is, a heat radiating member having a structure of copper plate / adhesive layer / graphite sheet / adhesive layer / graphite sheet / adhesive layer / copper plate was obtained.
In addition, 1/3 of the value which deducted the thickness of two copper plates and the thickness of two graphite sheets from the thickness of the whole heat radiating member was made into the thickness of an adhesive layer. The thickness of the heat radiating member was measured by Digimatic Indicator ID-C112CXB manufactured by Mitutoyo Corporation.

[Example 25]
In Example 1, an adhesive was obtained in the same manner as Example 1 except that the content of the thermally conductive filler was changed as shown in Table 3.
This adhesive is applied to an aluminum foil having a size of 50 mm × 50 mm and a thickness of 0.03 mm, and to a copper foil having a size of 50 mm × 50 mm and a thickness of 0.03 mm so that the thickness of the obtained adhesive layer is 1 μm. By applying in the same manner as in Example 1 and pre-drying so that the thickness of the resulting adhesive layer was 1 μm, an aluminum foil and a copper foil with an adhesive coating film were obtained, respectively.

  A 25 μm-thick graphite sheet (SS-1500) previously cut into 50 mm × 50 mm is sandwiched between the aluminum foil and copper foil with the adhesive coating, and the same method as in Example 1 is used. The heat radiating member was obtained while taking care not to shift the aluminum foil, the copper foil, and the graphite sheet.

  In the evaluation of heat dissipation characteristics, a heat-resistant paint (Okitsumo Co., Ltd .: heat-resistant paint one-touch) was sprayed on the aluminum foil so that the thickness of the coating film was about 20 μm and dried. Except for using this heat dissipation member, the heat dissipation characteristics were evaluated in the same manner as described above.

[Example 26]
In Example 1, an adhesive was obtained in the same manner as in Example 1 except that no heat conductive filler was used and cyclopentanone was used instead of NMP. Using the obtained adhesive, a heat radiating member was obtained in the same manner as in Example 1 except that the type of the metal layer and the thickness of the adhesive layer were changed as shown in Table 4.
In Example 26 and later, no heat resistant paint was applied when evaluating the heat dissipation characteristics.

[Example 27]
Using the adhesive obtained in Example 26, a laminate was obtained in the same manner as in Example 1 except that the type of metal plate and the thickness of the adhesive layer were changed as shown in Table 4.

  One side of the obtained laminate is sprayed with a heat-resistant paint (Okitsumo Co., Ltd .: heat-resistant paint one-touch) so that the thickness of the coating film is about 30 μm, and dried to form a resin layer on the laminate. A formed heat dissipation member was obtained. The surface (metal layer) opposite to the surface on which the resin layer of the heat radiating member is formed and the T0220 package transistor (Toshiba Corp .: 2SD2013) are double-sided tape (Sumitomo 3M Ltd., heat conductive adhesive). The heat dissipation characteristics were evaluated in the same manner as in the above <Evaluation of heat dissipation characteristics> except that the adhesive transfer tape No. 9885) was used.

[Example 28]
A laminate was obtained in the same manner as in Example 27.

10 wt% cordierite is added to the resin component in a solution obtained by dissolving 10 g of epoxy resin (jER828) in 90 g of NMP, and Shintaro Awatori Rentaro ARE-250 type is used at a rotational speed of 2000 rpm. After stirring for 5 minutes, a heat-dissipating paint was obtained by defoaming at a rotational speed of 2000 rpm for 5 minutes. After applying this paint on one copper foil of the laminate using a spin coater (Mikasa Co., Ltd .: 1H-D3 type) so that the thickness of the resulting resin layer is 0.03 mm, By heating on a hot plate set at 120 ° C. for 30 minutes, a heat dissipation member having a resin layer formed on the laminate was obtained.
In addition, the thickness of the resin layer was adjusted by adjusting the resin concentration in the paint and the rotation speed of the spin coater.

[Examples 29 to 36]
A laminate was obtained in the same manner as in Example 27.
A heat radiating member in which the resin layer was formed on the laminate in the same manner as in Example 28 except that the obtained laminate was used and the type of resin forming the resin layer and the type of filler were changed as shown in Table 4. Got.

[Example 37]
Using the adhesive obtained in Example 26, a laminate was obtained in the same manner as in Example 1 except that the types of the metal plate and the graphite sheet and the thickness of the adhesive layer were changed as shown in Table 4.
Using the obtained laminate, a heat radiating member having a resin layer formed on the laminate was obtained in the same manner as in Example 28 except that the type of resin forming the resin layer and the type of filler were changed as shown in Table 4. Obtained.

[Examination of thermally conductive filler]
Comparing the thermal diffusivity and thermal conductivity of the heat radiating members of Examples 1 to 5, the heat conductive filler is blended in the adhesive layer compared to the heat radiating member of Example 2 in which the heat conductive filler is not blended in the adhesive layer. It can be seen that the heat dissipation member is higher in thermal conductivity.

  Compared with aluminum nitride, the thermal conductivity of zinc oxide is about an order of magnitude smaller, but when comparing Examples 1 and 3, the heat dissipation member obtained when zinc oxide is blended in the adhesive layer and when aluminum nitride is blended There was no significant difference in thermal conductivity. Further, the thickness of the adhesive layer is thinner than the length of the zinc oxide needle-like portion. This is considered to be because the portion of the needle extending in the stacking direction of the heat dissipation member (laminated body) in the zinc oxide needle-like crystal is stuck in the graphite layer, and the portion efficiently converts the metal layer to the graphite layer. This is thought to be due to transferring heat.

  Nanodiamond shows the same heat dissipation performance as when other fillers are used, although the amount added is small. This is thought to be because the thermal conductivity of diamond is very high compared to other materials. Although the production amount of nanodiamond is small, it is considered that it should be used particularly when a small amount of a high performance heat sink is manufactured.

[Examination of heat conductive filler addition amount]
When Example 1 and Examples 6-8 are compared, it turns out that thermal conductivity becomes high, so that there are many compounding quantities of a heat conductive filler. However, if too much filler is added, the adhesive strength between the metal layer and the graphite layer tends to decrease, so an addition amount that achieves both thermal conductivity and adhesive strength is desirable.

[Examination of resin types]
When Example 1 and Comparative Example 1 are compared, the heat dissipation member obtained in Example 1 is in the stacking direction of the heat dissipation member (laminate) compared to the heat dissipation member laminated using a commercially available heat conductive adhesive transfer tape. High thermal conductivity.

  Moreover, the heat radiating member obtained in Example 12, Comparative Example 2 and Comparative Example 3 had an adhesive strength higher than that of any heat radiating member where the graphite layer was cleaved. When polyvinyl acetal resin is used as the type of resin for the adhesive layer, the adhesive strength can be maintained even if the thickness of the adhesive layer is reduced. Therefore, the thermal conductivity in the stacking direction of the resulting heat dissipation member (laminate) is In the case where a polyvinyl acetal resin is used as the type of resin for the adhesive layer, the highest is the case. Therefore, it can be seen that by using the polyvinyl acetal resin, a high-performance heat radiating member can be produced as compared with the case of using a commercially available adhesive.

When Example 2, 9-11 and Comparative Examples 4-8 are compared, when polyvinyl acetal resin is used as a kind of resin of a contact bonding layer, it turns out that the obtained heat radiating member shows favorable adhesiveness.
Since the polyvinyl acetal resin is excellent in adhesiveness to the metal layer and the graphite layer, the adhesive layer can be made thin. In particular, even when PVF-C2 is used and a thinner adhesive layer is formed, it can be seen that the thermal conductivity of the heat dissipation member is dramatically increased (Example 9).

  When an acrylic adhesive or an epoxy resin was used as the adhesive layer forming material, the metal layer and the graphite layer could not be bonded at all when the thickness of the adhesive layer was 1 μm.

  Moreover, as shown in Example 25, when the heat dissipation member of the present invention includes two or more metal layers, different metal layers can be used as necessary. Such a heat radiating member is, for example, a heat radiating member that has both heat radiation characteristics and rust resistance by using a copper layer with good thermal conductivity on the surface in contact with the heater and an aluminum layer that is not easily rusted on the opposite surface. You can also get The heat dissipation characteristics of this heat dissipation member are the heat dissipation characteristics of the heat dissipation member (Example 19) using only copper foil as the metal plate and the heat dissipation characteristics of the heat dissipation member (Example 20) using only the aluminum foil as the metal plate. Show intermediate properties.

[Examination of metal layer]
In Table 2, when Example 15 and Comparative Example 9 are compared, even when no heat conductive filler is blended in the adhesive layer, heat dissipation is better than a 0.2 mm thick copper plate having the same thickness as the heat dissipation member. Recognize. Moreover, when Example 14 and Comparative Example 10 are compared, the heat radiation member obtained by blending a heat conductive filler in the adhesive layer has a thickness of 0.4 mm, which is almost twice the thickness of the heat radiation member. It can be seen that the heat dissipation performance is better than that of the copper plate. Therefore, it can be seen that by using the heat dissipating member of the present invention, a high performance heat dissipating member having the same or higher heat dissipating performance and having a weight and thickness that is half that of copper can be obtained.

[Examination of resin layer]
The heat dissipating member of the present invention includes a heat dissipating resin layer containing a filler having high thermal conductivity similar to that used for the adhesive layer, a filler having a high far-infrared emissivity such as cordierite, mullite, and silica, or both. By installing on the outermost surface, it is possible to further increase the heat dissipation capability.

  In Table 4, it can be seen that the heat dissipation member having the resin layer can lower the temperature of the transistor more than the heat dissipation member having no resin layer, that is, the heat dissipation capability is improved. Furthermore, it can be seen that a heat dissipation member having a resin layer containing a filler such as cordierite, alumina, silicon carbide, and magnesium has a further improved heat dissipation capability compared to a heat dissipation member having a resin layer formed from a heat-resistant paint.

1: Heat dissipation member (laminate)
2: Metal layer 3: Adhesive layer 4, 4 ′, 4 ″: Graphite layer 5: Adhesive layer 6: Metal layer 7: Heating element 8: Hole 9: Slit

Claims (21)

Including a laminate in which a metal layer and a graphite layer are laminated via an adhesive layer;
The adhesive layer is formed from a composition containing a polyvinyl acetal resin containing the following structural units A, B and C,
The content of the polyvinyl acetal resin in the adhesive layer is 50 to 100% by weight,
A heat dissipation member, wherein the adhesive layer has a thickness of less than 10 μm.

(In the structural unit A, R is hydrogen.)

  The heat radiating member according to claim 1, wherein the composition further contains a thermally conductive filler. The heat radiating member according to claim 1 or 2, wherein the polyvinyl acetal resin further includes the following structural unit D.

(In the structural unit D, R ¹ is independently hydrogen or alkyl having 1 to 5 carbon atoms.)   The heat radiating member of any one of Claims 1-3 whose heat conductivity of the lamination direction of the said laminated body of the said contact bonding layer is 0.05-50 W / m * K.   The heat dissipation member according to any one of claims 2 to 4, wherein the adhesive layer contains 1 to 80% by volume of a heat conductive filler with respect to 100% by volume of the adhesive layer. The heat dissipation member according to claim 2 or 5, wherein the thermally conductive filler includes at least one powder selected from the group consisting of metal powder, metal oxide powder, metal nitride powder, and metal carbide powder.   The said heat conductive filler contains at least 1 sort (s) of powder chosen from the group which consists of aluminum nitride powder, aluminum oxide powder, zinc oxide powder, magnesium oxide powder, silicon carbide powder, and tungsten carbide powder. Heat dissipation member.   The heat radiating member according to claim 6 or 7, wherein the heat conductive filler has an average diameter of 0.001 to 30 µm. The heat dissipation member according to claim 2 or 5, wherein the thermally conductive filler is a filler containing a carbon material.   The heat radiating member according to claim 9, wherein the thermally conductive filler includes at least one powder selected from the group consisting of graphite powder, carbon nanotube, and diamond powder.   The heat radiating member according to any one of claims 1 to 10, wherein a thermal conductivity of the graphite layer in a direction substantially perpendicular to a stacking direction of the stacked body is 250 to 2000 W / m · K.   The heat radiating member according to claim 1, wherein the graphite layer has a thickness of 15 to 600 μm.   The heat radiating member of any one of Claims 1-12 whose thickness of the said metal layer is 0.01-100 times of the thickness of the said graphite layer.   The said metal layer is a layer containing at least 1 sort (s) of metal chosen from the group which consists of an alloy containing silver, copper, aluminum, nickel, and at least any one of these metals. The heat dissipating member according to Item 1.   The said metal layer is a layer containing 1 type of metal chosen from the group which consists of an alloy containing copper, aluminum, and at least any one of these metals of Claim 1-14. Heat dissipation member. The heat dissipation member has at least two metal layers containing one or more metals selected from the group consisting of copper, aluminum, and an alloy containing at least one of these metals,
The heat radiating member according to claim 1, wherein at least two of the metal layers are different layers.   The heat radiating member of any one of Claims 1-16 which has a resin layer in the single side | surface or both surfaces of the outermost layer of the said heat radiating member.   The heat radiating member according to claim 17, wherein the resin layer includes a filler made of an inorganic compound.   The resin layer is a group consisting of at least one resin selected from the group consisting of acrylic resin, epoxy resin, alkyd resin, urethane resin and nitrocellulose, and alumina, silica, cordierite, mullite, silicon carbide and magnesium oxide. The heat radiating member of Claim 17 or 18 containing the at least 1 sort (s) of compound chosen from.   The electronic device containing the heat radiating member of any one of Claims 1-19.   The battery containing the heat radiating member of any one of Claims 1-19.

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