TWI661026B - Thermally conductive adhesive sheet, manufacturing method thereof, and electronic device using the same - Google Patents

Abstract

The present invention provides an improvement in the dimensional accuracy of the high thermal conductivity portion and the low thermal conductivity portion of the thermally conductive adhesive sheet, and the low thermal conductivity of the low thermal conductivity portion can be easily laminated on an electronic device. A thermally conductive adhesive sheet that provides a sufficient temperature difference, a method for manufacturing the same, and an electronic device using the same. The thermally conductive adhesive sheet includes a base material including a high thermal conductivity portion and a low thermal conductivity portion, and an adhesive layer. An adhesive layer is laminated on one surface of the substrate, and the low-heat-conducting portion contains 20 to 90% by volume of hollow filler in the entire volume of the low-heat-conducting portion, and the low-heat-conducting portion is provided on the other side of the substrate. A surface opposite to a surface in contact with the adhesive layer, a surface opposite to a surface in contact with the adhesive layer of the high heat conduction portion, or at least one of the high heat conduction portion and the low heat conduction portion A thermally conductive adhesive sheet formed from a part of the thickness of the substrate, a method for manufacturing the same, and an electronic device using the same.

Description

Thermally conductive adhesive sheet, manufacturing method thereof, and electronic device using the same

The present invention relates to a thermally conductive adhesive sheet, particularly a thermally conductive adhesive sheet used in an electronic device, a method for manufacturing the same, and an electronic device using the same.

In the past, in the interior of electronic devices and the like, in order to dissipate heat or control heat flow in a specific direction, a sheet-like heat dissipating member having high thermal conductivity has been used. Examples of the electronic device include semiconductor devices such as a thermoelectric conversion device, a photoelectric conversion device, and a large-scale integrated circuit.

In recent years, with the miniaturization and high density of the semiconductor device, the heat generated from the inside of the semiconductor device becomes higher during operation, and the characteristics of the semiconductor device are reduced when the heat dissipation is insufficient. In some cases, malfunction may be caused, which may ultimately be related to the destruction of the semiconductor device or a reduction in the lifetime. As a method for efficiently dissipating the heat generated from the semiconductor device to the outside in this case, a heat-radiating sheet having excellent thermal conductivity is provided between the semiconductor device and the heat-radiating fin (metal member).

In addition, in these electronic devices, there is a person who performs the above-mentioned heat dissipation control in a thermoelectric conversion device, but if one side heat control is given to a thermoelectric element, In order to increase the temperature difference in the thickness direction of the thermoelectric element, the obtained power becomes larger. Therefore, it has been reviewed to use a sheet-shaped heat dissipation member to selectively control heat dissipation in a specific direction (the temperature difference is efficiently given to the interior of the thermoelectric element). . Patent Document 1 discloses a thermoelectric conversion element having a structure as shown in FIG. 7. That is, the P-type thermoelectric element 41 and the N-type thermoelectric element 42 are connected in series, and electrodes 43 for taking out thermoelectromotive force are arranged at both ends thereof to constitute a thermoelectric conversion module 46. Two sides of the thermoelectric conversion module 46 are provided with two The flexible thin film substrates 44 and 45 made of a material having a different thermal conductivity. Materials with low thermal conductivity (polyimide) 47, 48 are provided on the side of the film-like substrates 44, 45 on the joint surface with the thermoelectric conversion module 46, and on the side opposite to the joint surface with the thermoelectric conversion module 46, Materials (copper) 49 and 50 having high thermal conductivity are provided so as to be located on a part of the outer surfaces of the thin film substrates 44 and 45. Patent Document 2 discloses a thermoelectric conversion module having a structure shown in FIG. 8, and the electrode 54 which is also a high thermal conductivity member is buried in the low thermal conductivity members 51 and 52. The pair of thermoelectric elements 53 are conductive through The adhesive layer 55 and the insulating adhesive layer 56 are arranged.

[Prior technical literature]

[Patent Literature]

Patent Document 1: Japanese Patent No. 3981738

Patent Document 2: Japanese Patent Application Laid-Open No. 2011-35203

As described above, especially in electronic devices mainly composed of semiconductor devices, a heat-dissipating sheet capable of dissipating heat to the outside more efficiently, or having excellent thermal conductivity and selectively dissipating heat in a specific direction, is required to make the electronic device A thermally conductive sheet that functions as a temperature gradient inside. However, the present inventors reviewed the thermoelectric element of the thermoelectric conversion device described above by applying a thermally conductive adhesive sheet composed of a high thermal conductive part and a low thermal conductive part, and found that there is a high thermal conductive part or a low thermal conductive part with a thermal conductive adhesive sheet. The dimensional accuracy of the pattern is poor, and a new problem of a specific temperature difference is not obtained. The reason for the poor dimensional accuracy is a difference in internal stress including hardening shrinkage and the like in the high heat conductive portion and the low heat conductive portion constituting the heat conductive sheet.

The present invention has been made in view of the above problems, and an object thereof is to provide a dimensional accuracy improvement of a high thermal conductivity portion and a low thermal conductivity portion of a thermally conductive adhesive sheet, and a low thermal conductivity of the low thermal conductivity portion, so as to be easily laminated on an electronic device. A thermally conductive adhesive sheet capable of imparting a sufficient temperature difference to the inside of an electronic device, a method for manufacturing the same, and an electronic device using the same.

As a result of repeated active reviews by the present inventors in order to solve the above-mentioned problems, it was found that a base material including a high heat conductive portion and a low heat conductive portion, and an adhesive layer laminated on one surface of the base material constituted a heat conductive adhesive sheet, and The low-heat-conducting portion contains a specific amount (vol%) of a hollow filler, and the surface of the low-heat-conducting portion opposite to the surface in contact with the adhesive layer and the surface of the high-heat-conducting portion in contact with the adhesive layer The opposite side surface constitutes the other side of the base material, or at least one of the high heat conduction portion and the low heat conduction portion constitutes a part of the thickness of the base material, which can solve the above-mentioned problems, and thus completed the present invention.

That is, the present invention provides the following (1) to (15).

(1) A thermally conductive adhesive sheet comprising a base material including a high thermally conductive portion and a low thermally conductive portion, and a thermally conductive adhesive sheet having an adhesive layer portion, wherein the low thermally conductive portion is included in the entire volume of the low thermally conductive portion. Contains 20 to 90% by volume of hollow filler, and an adhesive layer is laminated on one surface of the substrate, and the other surface of the substrate is on the opposite side of the surface of the low heat conduction portion that is in contact with the adhesive layer The surface of the substrate, the surface opposite to the surface in contact with the adhesive layer of the high heat conduction portion, or at least one of the high heat conduction portion and the low heat conduction portion constitutes a part of the thickness of the substrate.

(2) The thermally conductive adhesive sheet according to the above (1), wherein the high-heat-conducting portion and the low-heat-conducting portion are each independent and constitute the entire thickness of the substrate.

(3) The thermally conductive adhesive sheet according to the above (1), wherein the high heat conductive portion and the low heat conductive portion are formed of a resin composition.

(4) The thermally conductive adhesive sheet according to the above (3), wherein the resin composition constituting the high thermally conductive portion contains a thermally conductive filler and / or a conductive carbon compound.

(5) The thermally conductive adhesive sheet according to the above (4), wherein the thermally conductive filler contains at least one selected from the group consisting of a metal oxide, a metal nitride, and a metal.

(6) The thermally conductive adhesive sheet according to the above (4), wherein the thermally conductive filler contains a metal oxide and a metal nitride.

(7) The thermally conductive adhesive sheet according to the above (4), wherein the conductive carbon compound includes at least one selected from the group consisting of carbon black, carbon nanotubes, graphene, and carbon nanofibers.

(8) The thermally conductive adhesive sheet according to the above (1), wherein the hollow filler is a glass hollow filler or a silicon dioxide hollow filler.

(9) The thermally conductive adhesive sheet according to the above (8), wherein the true density of the glass hollow filler and the silicon dioxide hollow filler is 0.1 to 0.6 g / cm ³ .

(10) The thermally conductive adhesive sheet according to any one of (3) to (9) above, wherein the composite hardening shrinkage ratio of the resin composition constituting the aforementioned high heat conduction portion and the resin composition constituting the aforementioned low heat conduction portion is 2 %the following.

(11) The thermally conductive adhesive sheet according to any one of the above (1) to (10), wherein the thermal conductivity of the high thermal conductivity portion of the aforementioned substrate is 0.5 (W / m · K) or more, and the thermal conductivity of the low thermal conductivity portion The rate is less than 0.5 (W / m · K).

(12) The thermally conductive adhesive sheet according to any one of (1) to (11) above, wherein the ratio of the thickness of the adhesive layer to the thickness of the substrate (adhesive layer / substrate), It is 0.005 ~ 1.0.

(13) The thermally conductive adhesive sheet according to any one of (1) to (12), wherein the adhesive layer contains a polysiloxane adhesive.

(14) An electronic device in which the thermally conductive adhesive sheet according to any one of (1) to (13) above is laminated.

(15) A method for producing a thermally conductive adhesive sheet, which is a method for producing a thermally conductive adhesive sheet according to any one of (1) to (13) above, which is contained on a support substrate that can be peeled off, and free resin A step of forming a base material with a high heat conductive portion formed of a composition and a low heat conductive portion formed of a resin composition; and a step of laminating an adhesive layer on the base material.

According to the thermally conductive adhesive sheet of the present invention, the dimensional accuracy of the high thermal conductive part and the low thermal conductive part that can realize the thermal conductive adhesive sheet can be improved, and the low thermal conductivity of the low thermal conductive part can be easily laminated on the electronic device. A thermally conductive adhesive sheet that imparts a sufficient temperature difference to the inside of an electronic device, a method for manufacturing the same, and an electronic device using the same.

1, 1A, 1B‧‧‧ Thermally conductive adhesive sheet

2‧‧‧ adherend

4, 4a, 4b ‧‧‧ high heat conduction part

5, 5a, 5b ‧‧‧ low heat conduction part

6‧‧‧Temperature difference measurement department

7‧‧‧ substrate

8‧‧‧ Adhesive layer

10‧‧‧ thermoelectric conversion device

11‧‧‧P type thermoelectric element

12‧‧‧N type thermoelectric element

13‧‧‧electrode (copper)

14a, 14b‧‧‧‧High heat conduction part

14’a, 14’b, 14’c‧‧‧High thermal conductivity

15’a, 15’b, 15’c‧‧‧‧Low thermal conductivity

15’a, 15’b‧‧‧Low heat conduction section

16‧‧‧thermoelectric conversion module

The first side of 17‧‧‧16

The second side of 18‧‧‧16

19‧‧‧ support

20‧‧‧ Adhesive layer

30‧‧‧ thermoelectric conversion device

31‧‧‧P type thermoelectric element

32‧‧‧N type thermoelectric element

33a, 33b, 33c‧‧‧ electrode (copper)

34‧‧‧High heat conduction section

35‧‧‧Low heat conduction section

36‧‧‧ support

37‧‧‧thermoelectric conversion module

38‧‧‧The lower surface of thermoelectric conversion device 30

39‧‧‧The upper surface of thermoelectric conversion device 30

40‧‧‧ Adhesive layer

41‧‧‧P type thermoelectric element

42‧‧‧N type thermoelectric element

43‧‧‧electrode (copper)

44‧‧‧ film substrate

45‧‧‧ film substrate

46‧‧‧ Thermoelectric Conversion Module

47, 48‧‧‧ materials with low thermal conductivity (polyimide)

49, 50‧‧‧ materials with high thermal conductivity (copper)

51, 52‧‧‧ low thermal conductivity components

53‧‧‧thermoelectric element

54‧‧‧electrode (copper)

55‧‧‧ conductive adhesive layer

56‧‧‧ Insulating adhesive layer

FIG. 1 is a perspective view showing an example of a thermally conductive adhesive sheet according to the present invention.

Fig. 2 is a sectional view showing various examples of the thermally conductive adhesive sheet of the present invention.

FIG. 3 is a view showing a thermally conductive adhesive sheet of the present invention attached to a thermoelectric Sectional view of an example of a thermoelectric conversion device when converting a module.

FIG. 4 shows an example of a perspective view in which the thermally conductive adhesive sheet and the thermoelectric conversion module of the present invention are decomposed into various constituent elements. (A) is a thermally conductive adhesive sheet provided on a thermoelectric element on the surface side of the support body of the thermoelectric conversion module. In a perspective view, (b) is a perspective view of a thermoelectric conversion module, and (c) is a perspective view of a thermally conductive adhesive sheet provided on a back surface side of a support.

Fig. 5 is an explanatory diagram for measuring the structure of the temperature difference between the high heat conduction portion and the low heat conduction portion of the thermally conductive adhesive sheet of the present invention, (a) is a thermally conductive adhesive sheet, and (b) is a glass used as an adherend A perspective view of the substrate.

FIG. 6 is a perspective view of a thermoelectric conversion module used in an embodiment of the present invention.

Fig. 7 is a cross-sectional view showing an example of the structure of a conventional thermoelectric conversion device.

Fig. 8 is a sectional view showing another example of the structure of a conventional thermoelectric conversion device.

[Thermal conductive adhesive sheet]

The thermally conductive sheet of the present invention includes a base material containing a high thermally conductive portion and a low thermally conductive portion, and a thermally conductive adhesive sheet with an adhesive layer. The low thermally conductive portion contains 20 to 90% by volume of a hollow filler in the entire volume, and One side of the substrate is laminated with an adhesive layer, and the other side of the substrate is The surface of the low heat conductive portion opposite to the surface in contact with the adhesive layer, the surface of the high heat conductive portion opposite to the surface in contact with the adhesive layer, or the high heat conductive portion and the low heat conductive portion are at least either One constitutes thermal conductivity and is a part of the thickness of the sheet.

The thermally conductive adhesive sheet of the present invention is composed of a substrate and an adhesive layer.

The structure and the like of the thermally conductive adhesive sheet of the present invention will be described using drawings.

<Substrate>

The base material is composed of a high thermally conductive portion and a low thermally conductive portion having different thermal conductivity.

FIG. 1 is a perspective view showing an example of a thermally conductive adhesive sheet according to the present invention. The thermally conductive adhesive sheet 1 is composed of a base material 7 including a high heat conductive portion 4a, 4b and a low heat conductive portion 5a, 5b, and an adhesive layer 8, and the high heat conductive portion and the low heat conductive portion are alternately arranged. That is, one side of the base material 7 is laminated with the adhesive layer 8, and the other side of the base material 7 is a surface on the opposite side of the low heat conductive portions 5 a and 5 b from the surface in contact with the adhesive layer, and the high heat conductive portion The surfaces of 4a and 4b opposite to the surface in contact with the adhesive layer 8 are constituted.

The arrangement (hereinafter sometimes referred to as the "thickness constitution") of the high heat conduction portion and the low heat conduction portion of the base material 7 constituting the thermally conductive adhesive sheet 1 is as described below, and is not particularly limited.

FIG. 2 shows various examples of the cross-sectional view (including the arrangement) of the thermally conductive adhesive sheet of the present invention. (A) of FIG. 2 is a cross-sectional view of FIG. 1, and each of the high heat conducting portion 4 and the low heat conducting portion 5 independently constitutes the entire thickness of the base material 7. degree. Moreover, (b)-(g) of FIG. 2 is a part of thickness of a base material in which at least any one of the high heat conduction part 4 and the low heat conduction part 5 is comprised. Specifically, parts (b) and (d) of FIG. 2 constitute a part of the thickness of the base material 7, and the surface of the base material 7 in contact with the adhesive layer 8 is formed only by the high heat conductive portion 4. Further, (c) and (e) in FIG. 2 constitute a part of the thickness of the base material 7, and the surface of the base material 7 in contact with the adhesive layer 8 is formed only by the low heat conductive portion 5. (F) of FIG. 2 is a part of the thickness of the base material 7 of the high heat conduction part 4, and the surface of the base material 7 contacting the adhesive layer 8 is formed by both the high heat conduction part 4 and the low heat conduction part 5. The surface of the base material 7 opposite to the surface in contact with the adhesive layer 8 is formed only by the low heat conduction portion 5. (G) of FIG. 2 is a part of the thickness of the base material 7 of the low heat conduction portion 5. The surface of the base material 7 in contact with the adhesive layer 8 is formed by both the high heat conduction portion 4 and the low heat conduction portion 5. The surface on the opposite side to the surface in contact with the adhesive layer 8 is formed only by the high heat conduction portion 4. The thickness of the base material 7 can be appropriately selected according to the specifications of the applied electronic device. For example, from the viewpoint of selectively dissipating heat in a specific direction, it is preferable to select a thickness configuration such as (a) to (g) in FIG. The overall thickness, that is, the thickness composition of (a) is even more preferable. In addition, from the viewpoint of efficiently dissipating heat generated inside the electronic device to the outside, the thickness configuration of (a) to (g) in FIG. 2 is selected in accordance with the specifications of the electronic device. At this time, if the volume of the high heat conduction portion is increased, and the contact area facing the device to be applied is increased, heat dissipation can be effectively controlled.

<Low heat conduction part>

The low thermal conductivity portion of the present invention is formed of a resin composition containing a hollow filler and a resin described later. The inclusion of a hollow filler suppresses the hardening shrinkage rate of the low heat conduction portion, and reduces the composite hardening shrinkage rate described later by reducing the difference between the hardening shrinkage rate of the high heat conduction portion and the low heat conduction portion. Degradation of the pattern size accuracy.

The shape of the aforementioned low heat conduction portion is not particularly limited, and can be appropriately changed according to the specifications of the electronic device described later. Here, the low thermal conductivity portion of the present invention means that the thermal conductivity is lower than the high thermal conductivity portion.

The hollow filler is not particularly limited, and known ones can be used, and examples include inorganic hollow glass (hollow bodies) such as glass hollow balls, silicon dioxide hollow balls, white sand hollow balls, charcoal ash hollow balls, and metal silicates. The hollow filler is an organic resin hollow filler including hollow spheres (hollow bodies) such as acrylonitrile, vinylidene chloride, phenol resin, epoxy resin, and urea resin. The hollow filler may be used singly or in combination of two or more kinds. Among them, the thermal conductivity of the substance itself is relatively low among metal oxides, and further, from the viewpoints of volume resistivity and cost, glass hollow fillers of inorganic hollow fillers or dioxide hollow fillers are preferred. Specifically, glass hollow fillers include, for example, GLASS BUBBLES (lime sodium borosilicate glass) manufactured by Sumitomo 3M Corporation, and silicon dioxide hollow fillers include, for example, SILINAX (registered trademark) manufactured by Nippon Steel Mining Corporation.

In the present invention, the term "hollow filler" refers to a housing having a filler as a constituent material and a hollow structure inside (except for air inside, It can also be filled with a gas such as an inert gas or a vacuum). The hollow structure is not particularly limited. For example, the hollow structure can be a sphere or an ellipsoid. The hollow structure can also be a plurality of types.

The shape of the hollow filler is not particularly limited, as long as it does not damage the electrical characteristics of the electronic device, component, etc. due to such contact or mechanical damage when attached to the applied electronic device, component, etc., For example, it may be any of a plate shape (including a scale shape), a spherical shape, a needle shape, a rod shape, and a fibrous shape.

The size of the hollow filler is from the viewpoint of uniformly dispersing the hollow filler in the thickness direction of the low-heat-conducting portion and reducing the thermal conductivity, and the average particle diameter is preferably 0.1 to 200 μm, more preferably 1 to 100 μm, and even more preferably 10 to 80 μm. , Preferably 20 to 50 μm. If the average particle diameter of the hollow filler is within this range, it is difficult to cause the particles to agglomerate, and the particles can be uniformly dispersed. In addition, the low heat conduction portion has a sufficient packing density, and the low heat conduction portion at the material interface does not become brittle. The average particle diameter can be measured by, for example, the Coulter Counter method.

The content of the hollow filler is appropriately adjusted according to its particle shape, and is 20 to 90% by volume, preferably 40 to 80% by volume, and more preferably 50 to 70% by volume in the adhesive resin composition. When the content of the hollow filler is less than 20% by volume, the pattern size accuracy of the high heat conduction portion and the low heat conduction portion of the hardened shrinkage change decreases. In addition, when the content of the hollow filler exceeds 90% by volume, the mechanical strength of the low heat conduction portion cannot be maintained. If the content of the hollow filler is within this range, it will effectively suppress hardening and shrinkage, and will have excellent heat dissipation characteristics, folding resistance, and bending resistance, while maintaining the mechanical strength of the low heat conduction portion.

The true density of the hollow filler is preferably from 0.1 to 0.6 g / cm ³ , more preferably from 0.2 to 0.5 g / cm ³ , and even more preferably from 0.3 to 0.4 g / cm ³ . If the true density of the hollow filler is within this range, the thermal insulation properties and pressure resistance will be excellent. The hollow filler will not be broken when the low thermal conductive portion is formed, and the thermal conductivity of the low thermal conductive portion will not be impaired.

Here, the "true density" is a density measured by a pycnometer method (a gas phase method based on Archimedes' principle). For example, the hydrometer can be measured using a hydrometer (gaseous displacement true density meter such as AccuPycll 1340 manufactured by Micromeritics).

(Resin)

The resin used in the present invention is not particularly limited, and any resin can be appropriately selected from users in the field of electronic parts and the like.

Examples of the resin include a thermosetting resin, a thermoplastic resin, and a photocurable resin. Polyethylene resins such as polyethylene and polypropylene constituting the aforementioned low thermal conductivity resins; polyolefin resins such as polystyrene; styrene resins such as polystyrene; acrylic resins such as polymethyl methacrylate; polyamides (nylon 6, nylon 66, etc.); Polymethylene resins such as poly-m-phenylene phthalate, poly-p-phenylene p-xylylenediamine; polyethylene terephthalate, polybutylene terephthalate, Polyester resins such as polyethylene naphthalate, polyacrylate; norbornene-based polymers, monocyclic cyclic olefin-based polymers, cyclic conjugated diene-based polymers, vinyl alicyclics Hydrocarbon polymers and alicyclic olefin polymers such as hydrides; vinyl chloride; polyimide; polyimide; imide; polyphenylene ether; polyetherketone, polyetheretherketone; polycarbonate; Poly Polyfluorene-based resins such as ethers; polyphenylene sulfide; silicone resins; and combinations of two or more of these polymers. Among these, from the viewpoints of excellent heat resistance and easy reduction of heat dissipation properties, polyamine resins, polyimides, polyimides, and silicone resins are preferred.

〈Other ingredients〉

The resin composition of the low-thermal-conduction section may contain a coloring agent such as a photopolymerization initiator, a cross-linking agent, a filler, a plasticizer, an anti-aging agent, an antioxidant, an ultraviolet absorber, a pigment, or a dye in an appropriate range as necessary. Additives such as adhesion-imparting agents, antistatic agents, and coupling agents.

<High heat conduction section>

The high thermal conductivity portion is formed of a resin composition, and there is no particular limitation as long as the material has a higher thermal conductivity than the aforementioned low thermal conductivity portion.

The shape of the high-heat-conducting portion is the same as the shape of the low-heat-conducting portion, and is not particularly limited, and may be appropriately changed according to specifications of an electronic device and the like described later.

Examples of the resin include similar resins such as thermosetting resins and energy ray-curable resins used in the aforementioned low-thermal-conducting portion. In general, from the viewpoints of mechanical properties, adhesion, and the like, the same resin as that of the low heat conduction portion is used.

In the high thermal conductivity portion, in order to suppress curing shrinkage and adjust to a desired thermal conductivity to be described later, it is preferably formed of a resin composition containing the resin, a thermally conductive filler, and / or a conductive carbon compound.

Hereinafter, a thermally conductive filler and a conductive carbon compound are sometimes referred to as "a substance for adjusting thermal conductivity".

(Thermal conductive filler and conductive carbon compound)

The thermally conductive filler is not particularly limited, and is preferably selected from metal oxides such as silicon dioxide, aluminum oxide, and magnesium oxide, metal nitrides such as silicon nitride, aluminum nitride, magnesium nitride, and boron nitride, copper, and aluminum. The conductive carbon compound is preferably at least one selected from carbon black, carbon nanotube (CNT), graphene, carbon nanofiber, and the like. These thermally conductive fillers and conductive carbon compounds may be used singly or in combination of two or more kinds. Among these, the thermal conductivity filler is preferably a thermally conductive filler. Furthermore, when a metal oxide and a metal nitride are included as the thermally conductive filler, the mass ratio of the metal oxide and the metal nitride is preferably 10:90 to 90:10, more preferably 20:80 to 80:20, and It is more preferably 50: 50 ~ 75: 25.

The shape of the material for adjusting the thermal conductivity is not particularly limited, as long as it is attached to the applied electronic device, component, etc., it will not damage the electrical characteristics of the electronic device, component, etc. due to such contact or mechanical damage. The shape is sufficient, and for example, it may be any of a plate shape (including a scale shape), a spherical shape, a needle shape, a rod shape, and a fiber shape. The thermally conductive filler used in the high thermally conductive portion does not include the aforementioned "hollow filler".

The size of the material for adjusting thermal conductivity From the viewpoint of improving the thermal conductivity by uniformly dispersing the material for adjusting thermal conductivity in the thickness direction of the high heat conductive portion, for example, the average particle diameter is preferably 0.1 to 200 μm, and more preferably 1 to 100 μm. , And more preferably 5 to 50 μm, and most preferably 10 to 30 μm. also, The average particle diameter can be measured by, for example, the Coulter Counter method. If the average particle diameter of the material for thermal conductivity adjustment is within this range, the thermal conductivity inside each material will not be reduced, and as a result, the thermal conductivity of the high thermal conductivity portion will be improved. In addition, it is not easy to cause particles to agglomerate with each other, and they can be uniformly dispersed. Furthermore, the filling density of the high heat conduction portion is sufficient, and the high heat conduction portion at the material interface does not become brittle.

The content of the thermal conductivity adjusting substance is appropriately adjusted according to the desired thermal conductivity, and it is preferably 40 to 99% by mass, more preferably 50 to 95% by mass, and most preferably 50 to 80% by mass in the resin composition. When the content of the thermal conductivity adjusting substance is within this range, the heat dissipation characteristics, folding resistance, and bending resistance are excellent, and the strength of the high thermal conductivity portion is maintained.

〈Other ingredients〉

In the resin composition in the high heat conduction portion, the same kind of additives may be contained in an appropriate range as necessary in the same manner as the aforementioned low heat conduction portion.

The thickness of each layer of the high heat conduction portion and the low heat conduction portion is preferably 1 to 200 μm, and more preferably 3 to 100 μm. Within this range, heat can be selectively radiated in a specific direction. In addition, the thicknesses of the respective layers of the high heat conductive portion and the low heat conductive portion may be the same or different.

Although the widths of the respective layers of the high heat conduction portion and the low heat conduction portion are appropriately adjusted according to the specifications of the applied electronic device, they are usually 0.01 to 3 mm, preferably 0.1 to 2 mm, and more preferably 0.5 to 1.5 mm. Within this range, heat can be selectively radiated in a specific direction. In addition, the widths of the respective layers of the high heat conduction portion and the low heat conduction portion may be the same or different.

The thermal conductivity of the high thermal conductivity portion may be sufficiently higher than that of the low thermal conductivity portion. The thermal conductivity is preferably 0.5 (W / m · K) or more, more preferably 1.0 (W / m · K) or more, and even 1.3 ( W / m.K) or more. The upper limit of the thermal conductivity of the high heat conductive portion is not particularly limited, but it is usually preferably 2000 (W / m · K) or less, and more preferably 500 (W / m · K) or less.

The thermal conductivity of the low heat conduction portion is preferably less than 0.5 (W / m · K), more preferably 0.3 (W / m · K) or less, and even more preferably 0.25 (W / m · K) or less. As long as the respective thermal conductivity of the high heat conductive portion and the low heat conductive portion is in the range described above, the heat can be selectively radiated toward a specific method.

The composite hardening shrinkage rate of the resin composition constituting the high-heat-conducting portion and the resin composition constituting the low-heat-conduction portion is preferably 2% or less, more preferably 1% or less, and still more preferably 0.8% or less. If the compound shrinkage rate is within this range, the pattern size accuracy of the high heat conduction portion and the low heat conduction portion is improved, and heat is selectively radiated in a specific direction, and a sufficient temperature difference can be given to the inside of the aforementioned electronic device and the like.

In the present invention, the "complex hardening shrinkage ratio" is a bar graph formed of, for example, a resin composition constituting the high-heat-conducting portion and a bar graph formed of a resin composition constituting the low-heat-conduction portion. The dimensional change before and after hardening of a composite pattern (see, for example, FIG. 1 and FIG. 2 (a)) formed by the pattern is defined and calculated by the following formula.

Compound hardening shrinkage (%) = [(Total width of strip pattern pitch before hardening-Total width of strip pattern pitch after hardening) / Total width of strip pattern pitch before hardening] × 100

Specifically, by using a digital multimeter (manufactured by Nippon Koki Co., Ltd., NRM-S3-XY type), the bar graph (adhesive resin composition) group of the specifications shown below before and after curing is measured. Sum of the width in the pitch direction of the strip pattern of the high heat conductive portion formed by the resin composition for the formation of the high heat conductive portion and the width in the pitch direction of the strip pattern of the low heat conductive portion formed by the resin composition for the formation of the low heat conductive portion The width (that is, the total width of the line pattern direction) is performed.

The specifications of the dimensional measurement samples are as follows.

． Bar pattern (adhesive resin composition) group: 100mm × 100mm, thickness 100μm

． High heat conduction section: strip width 1mm, length 100mm, thickness 100μm

． Low thermal conductivity: strip width 1mm, length 100mm, thickness 100μm

． Alternately arrange the high heat conduction part (stripe) and the low heat conduction part (stripe) toward the pitch direction (however, the space between the strips is set to zero)

In addition, for example, as shown in FIG. 2 (b) to FIG. 2 (g), the thickness of the thermally conductive adhesive sheet is different. (The thicknesses of the high heat conduction portion and the low heat conduction portion in FIG. Case; but at least one of the high heat conduction part and the low heat conduction part is a bar graph type) The size measurement sample is configured to maintain the heat conductivity and then the thickness of the sheet, and only the high heat conduction part and the low heat conduction part are used. The thickness of each layer is increased or decreased by an equal thickness, so that the total thickness of the entire layer becomes 100 μm.

The storage elastic modulus of the high heat conduction part at 150 ° C is preferably 0.1 MPa or more, more preferably 0.15 MPa or more, and even more preferably 1 MPa or more. In addition, the storage elastic modulus at 150 ° C. of the low heat conduction portion is preferably 0.1 MPa or more, more preferably 0.15 MPa or more, and even more preferably 1 MPa or more. When the storage elastic modulus of the high heat conduction part and the low heat conduction part at 150 ° C is 0.1 MPa or more, the thermal conductivity can be suppressed, and the sheet can be excessively deformed, and the heat can be stably dissipated. The upper limit of the storage elastic modulus of the high heat conductive portion and the low heat conductive portion at 150 ° C is not particularly limited, but is preferably 500 MPa or less, more preferably 100 MPa or less, and even more preferably 50 MPa or less.

The storage elastic modulus at 150 ° C. of the high heat conduction portion and the low heat conduction portion can be adjusted by adjusting the content of the resin composition or the substance for heat conduction adjustment.

The storage elastic modulus at 150 ° C was increased to 150 ° C at a temperature of 3 ° C / min at an initial temperature of 15 ° C and a frequency of 15 ° C using a dynamic elastic modulus measurement device (manufactured by TA Instruments, model name "DMAQ800"). Value measured at 11 Hz.

The arrangement of the high heat conduction portion and the low heat conduction portion and the shape thereof are not particularly limited as long as the intended performance is not impaired.

In the surface of the substrate opposite to the surface in contact with the adhesive (that is, when the low-heat-conducting portion and the high-heat-conducting portion separately constitute the entire thickness of the substrate: Figures 1, 2 (a)), the high-heat-conducting portion The step of the heat conduction portion is preferably 10 μm or less, more preferably 5 μm or less, and further preferably substantially non-existent.

Either a high heat conduction portion or a low heat conduction portion constitutes the base When part of the thickness of the material is used, for example, as shown in Figures 2 (b) and (c), the step difference between the high heat conduction part and the low heat conduction part is preferably 10 μm or less, more preferably 5 μm or less, and further preferably substantially non-existent. . In addition, in Fig. 2 (d) and (e), when a specific step difference is set between the high heat conducting portion and the low heat conducting portion, the thickness of the base material is the thickness between the high heat conducting portion and the low heat conducting portion and the high heat conducting portion and The step difference of the low heat conduction portion is preferably 10 to 90% with respect to the thickness of the substrate. And, in the base material, the volume ratio of the high heat conduction portion to the low heat conduction portion is preferably 10:90 to 90:10, more preferably 20:80 to 80:20, and still more preferably 30:70 to 70:30.

<Adhesive layer>

Examples of the adhesive constituting the adhesive layer include a rubber-based adhesive, an acrylic-based adhesive, a urethane-based adhesive, a polysiloxane-based adhesive, an olefin-based adhesive, and an epoxy-based adhesive. Know the adhesive. Among them, a polysiloxane adhesive is preferably used from the viewpoints of excellent insulation and heat resistance, high thermal conductivity, and excellent heat dissipation. In addition, since an adhesive is laminated on a substrate, when the adhesive layer is attached to a thermoelectric element, the substrate and the thermoelectric element are sufficiently insulated. Therefore, it may be contained in a high heat conduction portion of the substrate. The high thermal conductivity part has a higher thermal conductivity and is a highly conductive metal, so that a temperature difference can be provided more efficiently.

As long as the adhesive layer does not impair the object of the present invention, for example, an adhesion-imparting agent, a plasticizer, a photopolymerizable compound, a photopolymerization initiator, a foaming agent, a polymerization inhibitor, an anti-aging agent, Other ingredients such as fillers, coupling agents, antistatic agents.

The thickness of the adhesive layer is preferably 1 to 200 μm, and more preferably 5 to 100 μm. If it is within this range, when it is used as a thermally conductive adhesive sheet, it will not affect the control performance of heat radiation, so that heat can be selectively radiated in a specific direction. In addition, when the electronic device used requires insulation, the insulation can be maintained.

From the viewpoint of adjusting the thermal conductivity of the adhesive sheet and the balance between the heat dissipation control performance and the adhesive force, the ratio of the thickness of the substrate to the thickness of the adhesive layer (adhesive layer / substrate) is preferably 0.005 to 1.0, more It is preferably 0.01 to 0.8, and more preferably 0.1 to 0.5.

<Peeling Sheet>

The thermally conductive adhesive sheet may have a release sheet on the surface of the adhesive layer. Examples of the release sheet include papers such as cellophane, coated paper, and laminated paper, and those obtained by applying a release agent such as silicone resin or fluororesin to various plastic films. Although the thickness of the release sheet is not particularly limited, it is usually 20 to 150 μm. As the supporting substrate for the release sheet used in the present invention, a plastic film is preferably used.

<Electronic device>

Although the electronic device in which the thermally conductive adhesive sheet of the present invention is laminated is not particularly limited, from the viewpoint of thermal control such as heat dissipation, semiconductor devices such as electrothermal conversion devices, photoelectric conversion devices, and large-scale integrated circuits are listed. In particular, when the thermal conductivity is laminated on the thermoelectric conversion module of the thermoelectric conversion device, the heat can be selectively radiated in a specific direction. It can be improved, so it is better used in thermoelectric conversion devices.

The thermally conductive adhesive sheet may be laminated on one side of the electronic device, or may be laminated on both sides. Can be appropriately selected according to the specifications of the electronic device.

Hereinafter, the case of a thermoelectric conversion device will be described as an electronic device.

(Thermoelectric conversion device)

A thermoelectric conversion device is an electronic device that obtains electricity by applying a temperature difference to the inside of a thermoelectric conversion element that performs mutual energy conversion between heat and electricity.

FIG. 3 is a cross-sectional view showing an example of a thermoelectric conversion device in which the thermal conductivity of the present invention and a sheet are laminated on a thermoelectric conversion module. The thermoelectric conversion device 10 shown in FIG. 3 is composed of a P-type thermoelectric element 11 having a thin film made of a P-type material on a support (not shown), and N of a thin film made of an N-type material. A thermoelectric conversion element composed of a type thermoelectric element 12 and a thermoelectric conversion module 16 provided with electrodes 13; a thermally conductive adhesive layer 1A laminated on the first surface 17 of the thermoelectric conversion module 16; and further laminated with the foregoing The thermally conductive adhesive film 1B on the second surface 18 opposite to the first surface 17.

The thermally conductive adhesive sheet 1A includes a substrate containing high thermally conductive portions 14a, 14b and low thermally conductive portions 15a, 15b, 15c, and an adhesive layer laminated on one surface of the substrate, and the thermally conductive adhesive sheet 1B includes high The substrates of the thermally conductive portions 14'a, 14'b, and 14'c and the low thermally conductive portions 15'a and 15'b are bonded to the adhesive layer 20 on one surface of the substrate.

Figure 4 shows the thermal conductivity of the invention An example of a perspective view of the electric conversion module broken down into its constituent elements. In FIG. 4, (a) is a perspective view of the thermal conductivity of the thermoelectric element provided on the surface side of the support body 19 of the thermoelectric conversion module and the sheet 1A, (b) is a perspective view of the thermoelectric conversion mold 16, and (c) is a set The thermal conductivity on the back side of the support body 19 of the thermoelectric conversion module is a perspective view of the sheet 1B.

With such a configuration, the thermally self-conductive adhesive sheet 1A and the thermally conductive adhesive sheet 1B can be efficiently diffused. In addition, the thermally conductive adhesive sheet 1A is laminated so that the high thermally conductive portions 14a and 14b of the thermally conductive adhesive sheet 1A are not aligned with the high thermally conductive portions 14'a, 14'b, and 14'c of the thermally conductive adhesive sheet 1B. The heat can be selectively radiated in a specific direction. Thereby, a temperature difference can be efficiently provided to a thermoelectric conversion module, and a thermoelectric conversion device with high power generation efficiency can be obtained.

In addition, through the adhesive layer 20, the first surface 17 and the second surface 18 of the thermoelectric conversion module 16 can be adhered by increasing the adhesive force of the thermal conductive adhesive sheet 1A and the thermal conductive adhesive sheet 1B.

The thermoelectric conversion module 16 used in the present invention is, for example, as shown in FIG. 4 (b), on a support 19, it is composed of a P-type thermoelectric element 11, an N-type thermoelectric element 12, and an electrode 13. The P-type thermoelectric element 11 and the N-type thermoelectric element 12 are formed in a thin film shape by being connected in series, and are electrically connected by being joined to each other through an electrode 13. In addition, the P-type thermoelectric element 11 and the N-type thermoelectric element 12 in the thermoelectric conversion module 16 are shown in FIG. 3, and may be, for example, "electrode 13, P-type thermoelectric element 11, electrode 13, N-type thermoelectric element 12, and electrode 13 , ... ", or" electrode 13, P-type thermoelectric element 11, N-type thermoelectric element 12, electrode 13, P-type thermoelectric element 11, N-type thermoelectric element 12, electrode 13, ... ", in addition, it can also be like" electrode 13, P-type thermoelectric element 11, N-type thermoelectric element 12, P-type thermoelectric element 11, N-type thermoelectric The elements 12, ... electrodes 13 "are arranged in the same manner.

Although the foregoing thermoelectric elements are not particularly limited, in the temperature range of the heat source converted into electric energy by the thermoelectric conversion module, it is better to use a larger absolute value of Seebeck coefficient, lower thermal conductivity and higher electrical conductivity. So-called materials with higher thermoelectric performance index.

The materials constituting the P-type thermoelectric element and the N-type thermoelectric element are not particularly limited as long as they have thermoelectric conversion characteristics. Bismuth tellurides, Bi ₂ Te ₃ and other bismuth-tellurium thermoelectric semiconductor materials, GeTe, PbTe, etc. can be used. Telluride-based thermoelectric semiconductor materials, antimony-tellurium-based thermoelectric semiconductor materials, zinc-antimony-based thermoelectric semiconductor materials such as ZnSb, Zn ₃ Sb ₂ and Zn ₄ Sb ₃ , silicon-germanium-based thermoelectric semiconductor materials such as SiGe, Bi ₂ Se _3, etc. Biselenium-based thermoelectric semiconductor materials, β-FeSi ₂ , CrSi ₂ , MnSi _1.73 , Mg ₂ Si and other silicide-based thermoelectric conductor materials, oxide-based thermoelectric semiconductor materials, FeVAl, FeVAlSi, FeVTiAl and other Heusler materials Wait.

The thickness of the P-type thermoelectric element 11 and the N-type thermoelectric element 12 is preferably 0.1 to 100 μm, and more preferably 1 to 50 μm.

In addition, the thicknesses of the P-type thermoelectric element 11 and the N-type thermoelectric element 12 are not particularly limited, and may be the same thickness or different thicknesses.

[Method for manufacturing thermally conductive adhesive sheet]

The method for producing a thermally conductive adhesive sheet according to the present invention is to produce a base material and an adhesive layer including a high heat conductive portion and a low heat conductive portion. One side of the substrate is laminated with an adhesive layer, and the other side of the substrate is the side opposite to the surface of the low heat conductive portion that is in contact with the adhesive layer, and the side opposite to the surface of the high heat conductive portion that is in contact with the adhesive. A method for forming a thermally conductive adhesive sheet formed by a surface structure, or at least one of the high heat conductive portion and the low heat conductive portion constituting a part of the thickness of the base material, which is characterized by being contained on a peelable support base material, And a step of forming a base material with a high heat conduction portion formed of a resin composition, a base material with a low heat conduction portion formed of a resin composition, and laminating an adhesive layer on the base material.

<Substrate formation step>

It is a step of forming a substrate including a high thermal conductivity portion and a low thermal conductivity portion on a peelable support substrate.

(Supporting substrate)

As the peelable support substrate, the same as the release sheet on the surface of the adhesive of the aforementioned thermally conductive adhesive sheet can be used. Examples include paper of cellophane, coated paper, laminated paper, and various plastic films. Among them, a plastic film formed by coating a release agent such as a silicone resin or a fluororesin is preferred.

The release agent can be applied by a conventional method.

<Procedure for Forming High Heat Conduction Portion>

It is a step of forming a high heat conduction portion. The high heat-conducting portion is formed on the supporting base material using a resin composition, or on the supporting base material and the low heat-conducting portion. The coating method of the resin composition is not particularly limited as long as it uses, for example, A conventional method such as a stencil printing method, a glue application method, a screen printing method, a roll coating method, and a slot die may be formed.

In the adhesive resin composition used in the present invention, although the curing conditions when using a thermosetting adhesive resin are appropriately adjusted depending on the composition used, it is preferably 80 ° C to 150 ° C, and more preferably 90 ° C to 120 ° C. . Moreover, hardening may be performed under pressure as needed.

When a photocurable resin is used, for example, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, and the like can be used for curing by ultraviolet rays. The amount of light is usually 100 ~ 1500mJ / cm ² .

<Steps of Forming Low Thermal Conduction Portion>

It is a step of forming a low heat conduction portion. The low-heat-conducting portion is formed on the supporting base material, or on the supporting base material and the high-heat-conducting portion using the aforementioned resin composition containing the aforementioned resin and hollow filler. The coating method of the resin composition is not particularly limited, and it may be formed by a conventional method such as a stencil printing method, a glue-bonding method, a screen printing method, a roll coating method, a slit die, and the like, as in the case of the high heat conduction portion. . The hardening method is also the same as the hardening method of the high heat conduction portion.

There is no particular limitation on the order of forming the high heat conduction portion and the low heat conduction portion. It only needs to be appropriately selected according to the specifications of the electronic device.

<Adhesive Laminating Step>

Laminating an adhesive layer on the substrate obtained in the aforementioned substrate forming step The steps.

The formation of the adhesive can be performed using a conventional method, can be directly formed on the substrate, or an adhesive layer formed in advance on the release sheet can be bonded to the aforementioned substrate, and the adhesive layer can be transferred to the substrate. On the top.

According to the manufacturing method of the present invention, it is possible to control the heat escape or heat flow in the interior of the electronic device and the like in a specific direction by a simple method, and to suppress the hardening shrinkage, so that a thermally conductive adhesive sheet with high dimensional accuracy can be manufactured.

Examples

Next, the present invention will be described in more detail with examples, but the present invention is not limited to these examples.

The composite hardening shrinkage of the thermally conductive sheet (before laminating the adhesive layer) produced in the examples and comparative examples, the measurement of the thermal conductivity of the high and low thermally conductive parts, the evaluation of the temperature difference, and the evaluation of the electronic device are as follows get on.

(a) Measurement of the composite hardening shrinkage of thermally conductive adhesive sheet

The composite hardening shrinkage is measured by a digital multimeter (manufactured by Nippon Kogyo Co., Ltd., NRM-S3-XY type) with a strip pattern made of a resin composition for forming a high heat conduction part with a peeling support substrate, and a low heat conduction A strip pattern group (100 mm × 100 mm, thickness 100 μm) formed by compounding strip patterns formed by a resin composition for the part formation, but the composition including the thermal conductivity and the thickness of the sheet is different. The strip pattern is a high thermal conductivity part, (Or at least one of the cases of low thermal conductivity) Hardening of the total width in the distance direction (Hardening conditions: Depends on the resin composition used but is performed under optimal curing conditions.) The dimensional change before and after is calculated by the following formula.

Composite hardening shrinkage (%) = [(total width of bar pattern pitch before hardening-total width of bar pattern pitch after hardening) / total width of bar pattern pitch before hardening] × 100

In addition, the specifications of the bar graph are as described above. In the dimensional measurement method after hardening, in order to avoid the peelable support substrate to suppress the shrinkage of the hardened material, there is no peelable support substrate, that is, the self-peelable The support substrate is peeled off (however, the cured product is placed on a flat surface such as a glass substrate that does not prevent stress relaxation), and the cured product is relieved from the stress.

(b) Measurement of the thermal conductivity of the high heat conduction section and the low heat conduction section

The thermal conductivity of each of the high thermal conductivity portion and the low thermal conductivity portion was measured using a thermal conductivity measuring device (HC-110, manufactured by EKO Corporation).

(c) Temperature measurement of high heat conduction part and low heat conduction part

As shown in FIG. 5, the obtained thermally conductive adhesive sheet was peeled and exposed, and adhered to the upper surface of the adherend 2 made of soda glass (50 mm × 50 mm in thickness and 0.5 mm in thickness), and then another The peelable support substrate on one side is peeled off. Next, the lower surface of the adherend 2 was heated at 75 ° C. for 1 hour to stabilize the temperature, and then adhered to the upper surface of the adherend 2. K thermocouple (chromel-alumel, nickel-chromium-aluminum thermocouple) measures the temperature of the adherend. In addition, the thermocouple is provided on the adherend corresponding to a portion corresponding to the high heat conduction portion and the low heat conduction portion (measurement portion: temperature difference measurement portion 6; A, B, C, and D in FIG. 5), and is measured every 1 second. The temperature of the thermocouple was 5 minutes, and the average value of the obtained points was calculated.

(Manufacture of thermoelectric conversion module)

As shown in a part of FIG. 6, the P-type thermoelectric element 31 (P-type bismuth-tellurium-based thermoelectric semiconductor material) and the N-type thermoelectric element 32 (N-type bismuth-tellurium-based thermoelectric semiconductor material) are each of the same size (wide 1.7mm × length 100mm, thickness 0.5mm) is arranged on the support 36, and a copper electrode (copper electrode 33a: width 0.15mm × length 100mm, thickness 0.5mm) is provided between the two thermoelectric elements and the thermoelectric element; the copper electrode 33b: width 0.3mm × length 100mm, thickness 0.5mm; copper electrode 33c: width 0.15mm × length 100mm, thickness 0.5mm), a thermoelectric conversion module 37 is produced.

(Electrical Device Evaluation)

The lower surface 38 (see FIG. 6) of the thermoelectric conversion devices obtained in the examples and comparative examples was heated to 75 ° C. with the heating plate, and the upper surface 39 (see FIG. 6) on the opposite side was cooled to 25 ° C. After the temperature was maintained for 1 hour and the temperature was stabilized, the thermoelectromotive force V (V) and the resistance R (Ω) were measured. The output P (W) is calculated from P = V ² / R using the measured thermoelectromotive force V and resistance R.

(Example 1) (1) Production of thermally conductive adhesive sheet

Added 19.8 parts by mass of Polysiloxane A (made by Asahi Kasei WACKER Co., Ltd., "SilGel612-A"), 19.8 parts by mass of Polysiloxane Resin B (made by Asahi Kasei WACKER Co., Ltd., "SilGel612-B"), and a hardening retarder (Asahi Kasei WACKER Co., Ltd.) (PT88)) 0.4 parts by mass, 40 parts by mass of alumina (manufactured by Showa Denko Corporation, "ALUNABEADS CB-A20S", average particle diameter 20 µm) as a thermally conductive filler, boron nitride (manufactured by Showa Denko, "SHOB- "N UHP-2" (average particle size: 12 μm) 20 parts by mass, using rotation. A revolution kneader ("ARE-250" manufactured by THINKY) is mixed and dispersed to prepare a resin composition for forming a high heat conduction portion.

On the other hand, 31.7 parts by mass of polysiloxane resin A (Asahi Kasei WACKER Co., Ltd., "SilGel 612-A") and polysilicone resin B (Asahi Kasei WACKER Co., "SilGel 612-B") 31.7 parts by mass, hardening delay 0.6 mass parts of the additive (manufactured by Asahi Kasei WACKER Co., Ltd., "PT88"), 36 mass parts of glass hollow filler (manufactured by Sumitomo 3M, "GLASS BUBBLES S38", average particle diameter 40 μm, true density 0.38 g / cm ³ ) as a hollow filler (In the total volume of the low heat conduction part, containing 60% by volume of glass hollow filler), use rotation. A revolution kneading machine ("ARE-250" manufactured by THINKY) is mixed and dispersed to prepare a resin composition for forming a low heat conduction portion.

Next, a rubber spreader (manufactured by Musashi Engineering Co., Ltd., "ML- 808FXcom-CE ") The resin composition for forming a high heat conductive cloth is coated on a peelable surface of a peelable support ((LINTEC, PET50FD)) to form a stripe pattern (width 1mm × length 100mm). (Thickness: 50 μm, pattern center distance: 2 mm), and a high heat conduction portion 34 (see FIG. 6). Further, a resin composition for forming a low heat conduction portion was coated thereon using an applicator, and cured by heating at 150 ° C for 30 minutes. A low-heat-conducting portion 35 (see FIG. 6) having the same thickness as the high-heat-conducting portion is formed between the strip patterns of the high-heat-conducting portion, and a thermally conductive adhesive sheet is obtained. It is confirmed that the low-heat-conducting portion is not formed on the high-heat-conducting portion.

In addition, a silicone adhesive was applied to the release-treated surface of a release sheet ((LINTEC Corporation, PET50FD)) and dried at 90 ° C for 1 minute to form an adhesive layer having a thickness of 10 μm . The adhesive and The substrates are bonded together to produce a thermally conductive adhesive sheet composed of a release sheet and a peelable support substrate sandwiched therebetween. On the surface of the substrate opposite to the surface in contact with the adhesive layer, there is substantially no high thermal conductivity. The difference between the low heat conduction part and the low heat conduction part.

The storage elastic rate at 150 ° C of the high heat conduction section is 2.3 MPa, and the storage elastic rate at 150 ° C of the low heat conduction section is 3.4 MPa.

(2) Manufacturing of thermoelectric conversion device

Two obtained thermally conductive adhesive sheets were prepared, and the thermally conductive adhesive sheets were separately laminated on the surface of the thermoelectric conversion module 37 on the side of the thermoelectric conversion module 37 where the release sheet was removed and peeled off, and the surface on the support side, Next, the peelable support substrate is peeled off to make a double-sided layer. A thermoelectric conversion device incorporating a thermally conductive adhesive sheet.

(Example 2)

In addition to making the adhesive resin composition for forming a low heat conductive portion, 42.6 parts by mass of polysiloxane resin A (manufactured by Asahi Kasei WACKER Co., Ltd., "SilGel 612-A") and polysiloxane resin B (manufactured by Asahi Kasei WACKER Co., Ltd., "SilGel" 612-B ") 42.6 parts by mass, a hardening retarder (manufactured by Asahi Kasei WACKER Co., Ltd.," PT88 "), 0.8 parts by mass, and a glass hollow filler (manufactured by Sumitomo 3M," GLASS BUBBLES S38 ") with an average particle diameter of 40 μm, A true thermal conductivity adhesive sheet and a thermoelectric conversion device were produced in the same manner as in Example 1 except that the true density was 0.38 g / cm ³ ) and 14 parts by mass (the total volume of the low-heat-conducting portion contained 30% by volume of the glass hollow filler).

In addition, the storage elastic modulus at 150 ° C after hardening of the high heat conduction portion was 2.3 MPa, and the storage elastic modulus at 150 ° C after hardening of the low heat conduction portion was 0.2 MPa.

(Example 3)

The same procedure as in Example 1 was carried out except that 15 parts by mass of a polyamic acid solution (prepared by Nissan Chemical Industry Co., Ltd., SUNEVA 150) was used instead of the polysiloxane resins A and B as the resin. Thermally conductive adhesive sheet, and thermoelectric conversion device using the same.

The storage elastic modulus of the high thermal conductivity portion at 150 ° C is 4.1 MPa, and the storage elastic modulus of the low thermal conductivity portion at 150 ° C is 0.2 MPa.

(Example 4)

In the formation of the high thermal conductivity portion, 40 mass parts of carbon nanotubes (SWCTN, manufactured by Nano-C Corporation, average particle diameter of 0.9 to 1.3 nm) were used instead of boron nitride and A thermally conductive adhesive sheet was produced in the same manner as in Example 1 except that the substrate was made of alumina, and a thermoelectric conversion device was used.

The storage elastic modulus of the high thermal conductivity portion at 150 ° C is 4.0 MPa, and the storage elastic modulus of the low thermal conductivity portion at 150 ° C is 0.2 MPa.

(Example 5)

Using the aforementioned resin composition for forming a high heat-conducting portion used in Example 3, a strip-shaped pattern (width 1 mm × length 100 mm) was formed on the peeled surface of the peelable support substrate in the same manner as in Example 1. , Thickness 50μm, pattern center distance 2mm).

Next, an adhesive resin composition for forming a low thermal conductivity portion used in Example 3 was applied thereon, and after drying at 120 ° C. for 1 minute, a low thermal conductivity portion having a thickness of 75 μm was formed to prepare a substrate. It is formed by forming a low heat conduction portion having a thickness of 75 μm between the strip patterns of the high heat conduction portion, and forming a low heat conduction portion having a thickness of 25 μm on the high heat conduction portion. The absolute value of the thickness difference between the high heat conduction portion and the low heat conduction portion was 25 μm. In addition, an adhesive layer was laminated in the same manner as in Example 1 to produce a thermally conductive adhesive sheet having a structure as shown in FIG. 2 (c). In the surface of the substrate opposite to the surface in contact with the adhesive layer, the step difference between the high heat conduction portion and the low heat conduction portion does not substantially exist. in.

Using the obtained thermally conductive adhesive sheet, a thermoelectric conversion device manufactured as in Example 1 was used.

(Example 6)

The peelable support substrate was peeled from the substrate obtained in Example 5, and the adhesive layer was bonded to the exposed surface to produce a thermally conductive adhesive sheet having a structure as shown in FIG. 2 (f). All the surfaces of the obtained thermally conductive adhesive sheet on the opposite side of the surface in contact with the adhesive layer of the base material were composed of low thermally conductive portions. Using the obtained thermally conductive adhesive sheet, a thermoelectric conversion device produced in the same manner as in Example 1.

(Example 7)

A heat conductive adhesive sheet was produced in the same manner as in Example 5 except that the configuration of the high heat conductive portion and the low heat conductive portion were reversed. The structure of the obtained thermally conductive adhesive sheet was the structure shown in FIG. 2 (b).

(Example 8)

A heat-conductive adhesive sheet was produced in the same manner as in Example 6 except that the configuration of the high-heat-conducting portion and the low-heat-conducting portion was reversed. The structure of the obtained thermally conductive adhesive sheet was the structure shown in FIG. 2 (g).

(Example 9)

The resin for forming the high heat conduction part used in Example 3 was used The composition was formed in the same manner as in Example 1. On the release-treated surface of the peelable support substrate, a high heat conduction portion formed by a stripe pattern (width 1 mm × length 100 mm, thickness 50 μm, and pattern center distance 2 mm) was formed.

Next, the resin composition for forming the low-thermal-conduction part used in Example 3 was coated on the release-treated surface of the peelable support substrate, and dried at 120 ° C. for 1 minute to form a low-heat-conducting part of 25 μm.

Next, a base material is produced by bonding the low heat conductive portion and the high heat conductive portion. The obtained substrate had a structure in which a strip-shaped high-heat-conducting portion having a thickness of 50 μm was laminated on a low-heat-conducting portion having a thickness of 25 μm. In addition, an adhesive layer was laminated in the same manner as in Example 1 to produce a thermally conductive adhesive sheet having a structure as shown in FIG. 2 (e).

(Example 10)

A heat-conductive adhesive sheet was produced in the same manner as in Example 9 except that the configuration of the high-heat-conducting portion and the low-heat-conducting portion was reversed. The structure of the obtained thermally conductive adhesive sheet was the structure shown in FIG. 2 (d).

(Example 11)

Except for hollow nano-silicon dioxide ("SILINAX" (registered trademark), manufactured by Nippon Kogyo Co., Ltd., with an average particle diameter of 105 nm and a true density of 0.57 g / cm ³ ) using a hollow silica filler, the rest A thermoelectric conversion device was produced in the same manner as in Example 1.

(Comparative example 1)

A thermally conductive adhesive sheet was produced in the same manner as in Example 1 except that a hollow filler was not added to the low heat conduction section, and a thermoelectric conversion device was produced using the same.

In addition, the storage elastic modulus at 150 ° C after hardening of the high heat conduction portion was 2.3 MPa, and the storage elastic modulus at 150 ° C after hardening of the low heat conduction portion was 0.2 MPa.

(Comparative example 2)

Adhesive-processed PGS graphite flakes (manufactured by Panasonic Corporation, part number: EYGA091201M, PGS graphite flake thickness: 10 μm, adhesive thickness 10 μm, thermal conductivity: 1950 (W / m · K)) were used as thermal conductive adhesive sheets.

Two thermally conductive adhesive sheets were prepared, and the thermally conductive adhesive sheets were laminated on the surface of the thermoelectric conversion module 37 on the side where the thermoelectric elements are formed and on the side of the support, respectively, and fabricated on both sides of the thermally conductive adhesive sheet. Thermoelectric conversion device.

(Comparative example 3)

The thermally conductive adhesive sheet was not attached to the adherend, and the temperature difference was measured. In addition, the thermal conductivity adhesive sheet was not laminated on the thermoelectric conversion module 37, and evaluation of the electronic device was performed.

Table 1 shows the evaluation results of the composite hardening shrinkage, thermal conductivity, temperature difference, and / or electronic (thermoelectric conversion) device of the thermally conductive adhesive sheet and the thermal conductivity obtained in Examples 1 to 11 and Comparative Examples 1 to 3. Comparative Example 1 The evaluation result of the electronic device becomes 0, and it is considered that the thermal conductivity and the positional deviation of the sheet and the thermoelectric conversion element are large (derived from the composite hardening shrinkage), and the thermoelectric conversion element cannot be given a moderate temperature difference.

Compared with Comparative Example 1, the thermal conductivity adhesive sheet of the present invention used in Examples 1 to 11 shows that the composite hardening shrinkage is suppressed, the dimensional accuracy is improved, and the thermal conductivity is reduced. In addition, it can be seen that the temperature difference between the high heat conduction portion and the adjacent low heat conduction portion increases. In addition, a high output was obtained in the evaluation of the electronic device.

[Industrial availability]

When the thermal conductivity of the present invention is adhered to a thermoelectric conversion module of a thermoelectric conversion device, which is one of electronic devices in particular, it can be attached to thermoelectric elements and the like with good dimensional accuracy, and the thermal conductivity with the high heat conduction portion can be achieved. Since the difference is larger, a temperature difference can be efficiently provided in the thickness direction of the thermoelectric conversion element. Therefore, it is possible to perform power generation with high power generation efficiency. Compared with the previous type, the number of thermoelectric conversion modules can be reduced, which is related to the reduction in size and cost. At the same time, by using the thermally conductive adhesive sheet of the present invention, as a flexible thermoelectric conversion device, it can also be used without limitation in a place where it is installed on a waste heat source or a heat radiation source having an uneven surface.

Claims (15)

A thermally conductive adhesive sheet comprising a base material including a high thermally conductive part and a low thermally conductive part, and a thermally conductive adhesive sheet having an adhesive layer. The low thermally conductive part contains 20 to 90 in the entire volume of the low thermally conductive part. The vol% hollow filler is further laminated with an adhesive layer on one side of the substrate, and the other side of the substrate is a surface on the opposite side of the surface of the low-heat-conducting portion in contact with the adhesive layer, and The surface of the high heat conduction portion opposite to the surface in contact with the adhesive layer is formed, or at least one of the high heat conduction portion and the low heat conduction portion constitutes a part of the thickness of the substrate. The sheet of thermal conductivity according to claim 1, wherein the high-heat-conducting portion and the low-heat-conducting portion independently constitute the entire thickness of the substrate. The heat conductive adhesive sheet according to claim 1, wherein the high heat conductive portion and the low heat conductive portion are formed of a resin composition. The heat conductive adhesive sheet according to claim 3, wherein the resin composition constituting the high heat conductive portion contains a heat conductive filler and / or a conductive carbon compound. The thermally conductive adhesive sheet according to claim 4, wherein the thermally conductive filler contains at least one selected from the group consisting of a metal oxide, a metal nitride, and a metal. The thermally conductive adhesive sheet according to claim 4, wherein the thermally conductive filler contains a metal oxide and a metal nitride. The thermally conductive adhesive sheet according to claim 4, wherein the conductive carbon compound includes at least one selected from the group consisting of carbon black, carbon nanotubes, graphene, and carbon nanofibers. The thermally conductive adhesive sheet according to claim 1, wherein the hollow filler is a glass hollow filler or a silicon dioxide hollow filler. For example, the thermal conductivity adhesive sheet of claim 8, wherein the true density of the aforementioned glass hollow filler and silicon dioxide hollow filler is 0.1 to 0.6 g / cm ³ . The thermally conductive adhesive sheet according to any one of claims 3 to 9, wherein the composite hardening shrinkage ratio of the resin composition constituting the high-heat-conducting portion and the resin composition constituting the low-heat-conducting portion is 2% or less. The thermally conductive adhesive sheet according to any one of claims 1 to 9, wherein the thermal conductivity of the high thermal conductivity portion of the aforementioned substrate is 0.5 (W / m · K) or more, and the thermal conductivity of the low thermal conductivity portion is less than 0.5 ( W / m.K). The thermally conductive adhesive sheet according to any one of claims 1 to 9, wherein the ratio of the thickness of the adhesive layer (adhesive layer / substrate) to the thickness of the substrate is 0.005 to 1.0. The thermally conductive adhesive sheet according to any one of claims 1 to 9, wherein the adhesive layer contains a polysiloxane adhesive. An electronic device in which a thermally conductive adhesive sheet according to any one of claims 1 to 13 is laminated. A method for producing a thermally conductive adhesive sheet, which is a method for producing the thermally conductive adhesive sheet according to any one of claims 1 to 13, which is contained on a support substrate that can be peeled off and has a high thermal conductivity formed by a free resin composition. A step of forming a base material with a low thermally conductive portion formed of a resin composition; and a step of laminating an adhesive layer on the base material.