Heat dissipation coating structure, electronic component using the heat dissipation coating structure, electronic device

Abstract

To provide a heat dissipation coating structure superior in heat dissipation and having durability.SOLUTION: The heat dissipation coating structure is a heat dissipation coating structure that has heat-dissipating particles and resin. The heat-dissipating particles are composed of oxides containing at least two elements selected from the group consisting of aluminum, magnesium, and silicon, which are particles with an average particle size of 0.1 to 30 μm. The average thickness of the heat-dissipation coating structure is more than 10 times the average particle diameter of heat-dissipating particles. The end of the heat dissipation coating structure has irregularities caused by a resin, and heat-dissipating particles exist on the uneven surface.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a heat radiation coating film structure capable of radiating heat from a heating element to the outside via thermal radiation, as well as an electronic member and an electronic device including the heat radiation coating film structure. Background Art

[0002] In recent years, along with the miniaturization and higher density of power devices and semiconductor packages, the heat generation density of devices has increased. Therefore, for electronic members mounted in devices, there is an increasing demand for technology that efficiently dissipates heat generated from each electronic member so as not to exceed the guaranteed operating temperature, which has become essential.

[0003] As heat dissipation means, fins utilizing convection and heat conductive sheets utilizing heat conduction are generally used. However, as a heat dissipation means, it is difficult to dissipate heat to below the guaranteed operating temperature of a heating element such as a heat-generating device included in a device only with such conventional heat countermeasure members. In recent years, heat dissipation paints and heat dissipation coating films using thermal radiation, as well as sheets and members having a heat dissipation coating film formed on their surfaces, have attracted attention as means capable of dissipating heat without securing extra space.

[0004] FIG. 8(a) is a cross-sectional view of a planar structure (hereinafter referred to as "heat radiation coating film structure 33") produced on a base material 31 by a conventional method described in Patent Document 1, for example. As shown in FIG. 8(a), the heat radiation coating film structure 33 is composed of a resin 30 and heat transfer particles 32. Heat from the base material 31 is transferred in the thickness direction within the heat radiation coating film structure 33 mainly by the heat transfer particles 32 present in the heat radiation coating film structure 33, and is dissipated from the surface of the heat radiation coating film structure 33. When forming this heat radiation coating film structure 33, an ink containing the resin 30 and the heat transfer particles 32 is prepared, applied, and dried, thereby producing the heat radiation coating film structure 33 containing a certain amount of heat transfer particles 32 having a large particle diameter in the heat radiation coating film structure 33. In addition, the technical content is disclosed that irregularities due to the heat transfer particles 32 having a large particle diameter are formed on the surface of the heat radiation coating film structure 33, and the increased surface area improves the heat dissipation performance. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] International Publication No. 2009 / 142036 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, the manufacturing method of the heat dissipation coating structure 33 described in Patent Document 1 presents the following problems, particularly at the end side and surrounding areas of the heat dissipation coating structure 33. Figures 8(b) and (c) show cross-sectional views of the heat dissipation coating structure 33 around the end of Patent Document 1. Here, the end refers to the contact point 34 between the end of the heat dissipation coating structure 33 and the substrate 31, the surrounding area refers to a 10 mm range 35 extending inward from the end of the heat dissipation coating structure, and the end side refers to the surface 36 in the surrounding area 35 of the heat dissipation coating structure 33 where the film thickness of the heat dissipation coating structure thins towards the end 34.

[0007] For example, Figure 8(b) shows a cross-sectional view of the area around the edge 35 of the heat-dissipating coating structure 33 when the resin content of the ink used in the manufacturing method of the heat-dissipating coating structure 33 is low or the viscosity is high. In this case, heat transfer particles 32 with a large particle size are present around the edge 34. However, due to the thermal expansion and contraction of the heat-dissipating coating structure 33, cracks and peeling are likely to occur at the interface with the substrate 31 (A in the figure) or at the interface between the heat transfer particles and the resin (B in the figure).

[0008] Furthermore, Figure 8(c) shows a cross-sectional view of the area around the end of the heat-dissipating coating structure 33 when the resin content of the ink is high or the viscosity is low. In this case, the resin 30 tends to flow out at the side surface of the end, forming a resin-rich film (C in the figure). In this case, stress is likely to occur due to the difference between the thermal expansion and contraction of the resin and the thermal expansion and contraction of the substrate, which makes it easy for cracks to enter the side surface 36 of the end, and these cracks propagate to the area around the end, causing a problem in which the durability of the film is reduced. In other words, the method described in Patent Document 1 has the problem that cracks, fissures, and peeling of the heat dissipation coating structure 33 are more likely to occur around the edges of the heat dissipation coating structure 33.

[0009] Therefore, the purpose of this disclosure is to provide a heat-dissipating coating structure that has excellent heat dissipation properties and durability. [Means for solving the problem]

[0010] To achieve the above objective, the heat dissipation coating structure according to this disclosure is a heat dissipation coating structure having heat dissipating particles and a resin, wherein the heat dissipating particles are particles with an average particle diameter of 0.1 to 30 μm, composed of oxides containing at least two elements selected from the group consisting of aluminum, magnesium, and silicon, the average thickness of the heat dissipation coating structure is 10 times or more the average particle diameter of the heat dissipating particles, and the end surfaces of the heat dissipation coating structure have irregularities due to the resin, with heat dissipating particles present on the surface of the irregularities. [Effects of the Invention]

[0011] According to the heat dissipation coating structure described herein, it is possible to obtain a heat dissipation coating structure that has excellent heat dissipation properties and resistance to cracks, fissures, and peeling caused by thermal expansion and contraction. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic cross-sectional view showing the cross-sectional structure around the end of the heat dissipation coating structure according to Embodiment 1. [Figure 2] (a) to (e) are schematic cross-sectional views showing each step of the manufacturing method for the heat dissipation coating structure according to Embodiment 1. [Figure 3] A schematic cross-sectional view showing the cross-sectional structure around the end of the heat-dissipating coating structure during the heat curing step of the manufacturing method for the heat-dissipating coating structure according to Embodiment 1. [Figure 4] This is a schematic cross-sectional view showing the cross-sectional structure of an electronic component according to Embodiment 1. [Figure 5] This figure shows the structure of the electronic device according to Embodiment 1. [Figure 6] It is a cross-sectional view showing the cross-sectional structure of an evaluation element in Comparative Examples and Examples. [Figure 7] It is a schematic cross-sectional view showing the cross-sectional structure around the end portion of the heat-dissipating coating film structure in the heat-curing step of the method for producing a heat-dissipating coating film structure according to Embodiment 1 [Figure 8] It is a schematic cross-sectional view showing the cross-sectional structure of the heat-dissipating coating film structure in Patent Document 1. [Figure 9] It is Table 1 showing detailed contents such as production conditions including compounding ratio, set temperature, etc., and evaluation results of heat-dissipating coating film structures produced in Examples and Comparative Examples. MODE FOR CARRYING OUT THE INVENTION

[0013] A heat-dissipating coating film structure according to a first aspect is a heat-dissipating coating film structure comprising heat-dissipating particles and a resin, wherein the heat-dissipating particles are particles having an average particle diameter of 0.1 to 30 µm composed of an oxide containing at least two elements selected from the group consisting of aluminum, magnesium, and silicon, the average thickness of the heat-dissipating coating film structure is 10 times or more the average particle diameter of the heat-dissipating particles, and the end side surface of the heat-dissipating coating film structure has irregularities formed by the resin, and the heat-dissipating particles are present on the surfaces of the irregularities.

[0014] In the heat-dissipating coating film structure according to a second aspect, in the first aspect described above, the maximum difference between the irregularities formed by the resin may be not less than 1 / 30 and not more than 1 / 2 of the average film thickness of the heat-dissipating coating film structure.

[0015] In the heat-dissipating coating film structure according to a third aspect, in the first aspect described above, the resin may be selected from the group consisting of epoxy resins, epoxy polyester resins, polyester resins, and acrylic resins.

[0016] An electronic member according to a fourth aspect comprises: an electronic member having a heating element; and the heat-dissipating coating film structure according to any one of the first to third aspects described above, which is disposed in direct or indirect contact with the heating element.

[0017] The electronic member according to the fifth aspect comprises an electronic device having a heating element, and the heat-dissipating coating film structure according to any one of the first to third aspects described above, which is disposed in direct or indirect contact with the heating element.

[0018] The method for producing a heat-dissipating coating film structure according to the sixth aspect is a method for producing a heat-dissipating coating film structure, wherein a heat-dissipating coating film structure containing heat-dissipating particles and a resin is formed on a substrate surface, the method comprising: a composite treatment step of forming composite particles in which surfaces of particles formed of a resin are coated with the heat-dissipating particles; a film forming step of forming a powder film by laminating the composite particles; and a thermosetting step of heating the powder film to cure the resin while melting the resin, wherein in the thermosetting step, a temperature around an end portion of the heat-dissipating coating film structure on the surface of the substrate is set to be lower than a temperature in a region other than around the end portion.

[0019] In the method for producing a heat-dissipating coating film structure according to the seventh aspect, in the sixth aspect described above, when the heat-dissipating coating film structure is solidified while being pressurized in the thermosetting step, a pressing force applied around an end portion of the heat-dissipating coating film structure may be weaker than that in a region other than around the end portion.

[0020] Hereinafter, the heat-dissipating coating film structure according to the embodiments of the present disclosure will be described in further detail with reference to the drawings.

[0021] (Embodiment 1) First, the heat-dissipating coating film structure 1 according to Embodiment 1 will be described in detail with reference to FIG. 1. FIG. 1 is a cross-sectional view showing a cross-sectional structure around an end portion of the heat-dissipating coating film structure 1 according to Embodiment 1. For convenience, the thickness direction is defined as the Z direction, and the right hand side of the drawing is defined as the X direction. The heat-dissipating coating structure 1 according to Embodiment 1 is a planar structure formed on the surface of a substrate 4, and is composed of at least heat-dissipating particles 2 and resin 3. The heat-dissipating particles 2 are particles with an average particle diameter of 0.1 to 30 μm, composed of oxides containing at least two elements selected from the group consisting of aluminum, magnesium, and silicon. The thickness of the heat-dissipating coating structure 1 is 10 times or more the average particle diameter of the heat-dissipating particles 2. The end surface 5 of the heat-dissipating coating structure 1 has irregularities formed by the resin 3 in the depth direction (Y direction) in the figure (not shown), and the heat-dissipating particles 2 are present on this irregular surface.

[0022] By adopting the above configuration, stress due to thermal expansion and contraction is alleviated at the end periphery 7 and end side surface 5 of the heat dissipation coating structure 1, making it less likely for cracks or fissures to occur at the end side surface 5 and delamination at the end periphery 7 of the heat dissipation coating structure 1 to occur. Furthermore, the surface area of ​​the end side surface 5 of the heat dissipation coating structure 1 is increased, and an improvement in heat dissipation performance can also be expected.

[0023] Here, end 6 refers to the point of contact between the end of the heat dissipation coating structure 1 and the substrate 4, and the end periphery 7 refers to the area 10 mm inward from end 6 within the heat dissipation coating structure. Furthermore, the end side surface 5 refers to the surface of the heat dissipation coating structure 1 in the end periphery 7 where the film thickness of the heat dissipation coating structure 1 decreases towards end 6. Furthermore, the irregularities on the end side surface 5 refer to the maximum length of the convex and concave parts of the irregular shape of the end side surface 5 in a cross-sectional view obtained by cutting the heat dissipation coating structure 1 parallel to end 6 at an arbitrary point on the end side surface 5 (for example, X in the figure).

[0024] Next, it is preferable that the maximum difference in irregularities on the end surface 5 of the heat dissipation coating structure 1 according to Embodiment 1 is 1 / 30 or more and 1 / 2 or less of the average film thickness of the heat dissipation coating. By adopting this configuration, the effect of improving the durability of the heat dissipation coating structure 1 described above can be obtained more stably.

[0025] Furthermore, we can also provide electronic components including the heat dissipation coating structure described above, and electronic devices including said electronic components.

[0026] The materials used in the heat dissipation coating structure 1 according to this embodiment 1 will be described in detail below.

[0027] [Heat dissipating particles 2] <Types of heat-dissipating particles (2)> The far-infrared emissivity on the surface of the heat-dissipating coating structure 1 is affected not only by the heat-dissipating particles 2 that may be present near the surface of the heat-dissipating coating structure 1, but also by the resin 3. Generally, the far-infrared emissivity of the resin 3 is between 0.6 and 0.8. Therefore, the far-infrared emissivity of the heat-dissipating particles 2 is greater than that of the resin 3, preferably 0.8 or higher, and more preferably 0.85 or higher. If it is less than 0.8, it may be affected by the far-infrared emissivity of the resin 3, so the far-infrared emissivity of the heat-dissipating coating structure 1 may be less than 0.8, resulting in reduced heat radiation and insufficient heat dissipation performance.

[0028] The objective is to make the far-infrared emissivity of the heat-dissipating coating structure 1 preferably 0.85 or higher, more preferably 0.9 or higher. Therefore, in this disclosure, the heat-dissipating particles 2 basically use an oxide containing at least two elements selected from the group consisting of aluminum, magnesium, and silicon. By containing at least two of these components of aluminum, magnesium, and silicon, the peaks of far-infrared emissivity caused by these components can overlap. As a result, the average value of the far-infrared emissivity in the wavelength range of 2 μm to 22 μm, which contributes to heat transfer in electronic components, can be 0.85 or higher. Preferably, it is desirable to use magnesium silicates such as talc or cordierite, magnesium-aluminum carbonates such as hydrotalcite, or aluminosilicates such as zeolite or bentonite. Furthermore, an oxide containing at least two elements selected from the group consisting of aluminum, magnesium, and silicon, with a specific surface area of ​​7 m² is also desirable. 2 / g or more 50m 2 The particles may be less than or equal to / g.

[0029] Here, far-infrared emissivity is the ratio of values ​​between 0 and 1 relative to the ideal state, where the value of blackbody radiation, which is closest to the ideal state, is set to 1.

[0030] <Particle size of heat-dissipating particle 2> The average particle diameter of the heat-dissipating particles 2 is, for example, in the range of 0.1 μm to 30 μm, preferably in the range of 0.3 μm to 10 μm. If the particle diameter of the heat-dissipating particles 2 is smaller than 0.1 μm, the number of contact points between the heat-dissipating particles 2 in the thickness direction of the heat-dissipating coating structure 1 will increase. As a result, the thermal resistance at the contact point interfaces will increase, impairing thermal conductivity, which may reduce the heat dissipation performance of the heat-dissipating coating structure 1. On the other hand, if the particle size of the heat-dissipating particles 2 is larger than 30 μm, the heat-dissipating particles 2 may detach from the surface of the heat-dissipating coating structure 1 due to wear and friction, and cracking and peeling of the heat-dissipating coating structure 1 may occur, which may reduce the heat dissipation performance of the heat-dissipating coating structure 1. In this embodiment, the average particle diameter refers to the volume-average diameter of each particle.

[0031] <Types of resin 3> Resin 3 is preferably a thermoplastic resin such as polyethylene or polypropylene, or a thermosetting resin such as epoxy resin, epoxy polyester resin, polyester resin, or acrylic resin. Specifically, it is preferable that the resin melts when heated and solidifies when finally cooled.

[0032] <Particle size of resin 3> The particle size of resin 3 is, for example, within the range of 1 μm to 500 μm, and preferably 2 μm to 300 μm. Furthermore, 2 μm to 150 μm is desirable. In addition, the particle size of resin 3 is preferably 2 to 50 times the average particle size of heat dissipating particles 2, and preferably 5 to 30 times the average particle size of heat dissipating particles 2.

[0033] <Method for manufacturing the heat-dissipating coating structure 1> Next, the method for manufacturing the heat-dissipating coating structure 1 according to Embodiment 1 will be described with reference to Figure 2. Specifically, the method for manufacturing the heat-dissipating coating structure 1, which is composed of at least heat-dissipating particles 2 and resin 3, will be described. It is also possible to add small amounts of pigment or binder (not shown) as needed. Figure 2 is a schematic cross-sectional view showing each step of the method for manufacturing the heat-dissipating coating structure 1 according to Embodiment 1.

[0034] The method for manufacturing the heat dissipation coating structure 1 includes the following steps. (1) Prepare particles consisting of heat-dissipating particles 2 and resin 3 (hereinafter referred to as "resin 3 particles") (Figure 2(a)). (2) A composite particle 8 is formed by combining each of the components (composite processing step (Figure 2(b))). (3) The composite particles 8 are spread on the surface of a metal structure (substrate) 4, such as aluminum or stainless steel, to form a powder layer 9 (powder layer formation process (Figure 2(c))). (4) The powder layer 9 is heated and / or pressurized to push out the gas present in the space 10 between the composite particles 8, rearranging the composite particles 8 and forming the arranged layer 11 (arrangement step (Figure 2(d))). (5) Furthermore, the array layer 11 is heated or pressurized as necessary to soften the resin 3 and flatten the surface of the array layer 11, and then hardened in that state to form the heat dissipation coating structure 1 (heat curing process (Figure 2(e))). Through the above steps, a heat dissipation coating structure 1 can be obtained.

[0035] Here, it is important to set the temperature around the edges of the powder layer 9 or the array layer 11 lower than the temperature in the center, at least during the arraying process or the heat curing process. For example, let's explain using Figure 3. Figure 3 is a schematic diagram showing the apparatus configuration when the array layer 11 is heated and pressurized to form the heat dissipation coating structure 1. For example, in Figure 3(a), the substrate 4 with the array layer 11 formed on it is placed on the heating stand 12 and heated to form the heat dissipation coating structure 1. Here, by configuring the edges of the substrate 4 to protrude from the heating stand 12, it is possible to suppress the temperature rise around the edges of the heat dissipation coating structure 1. It is also possible to create a temperature difference by flowing air 43 or other airflow around the protruding edges of the substrate 4 and its vicinity. What is important here is to set the temperature around the edges of the heat dissipation coating structure 1 (arrangement layer 11) lower than the temperature in the center.

[0036] Furthermore, another method will be explained using Figure 3(b). At least in the heat curing process, a substrate 4 with the arrayed layer 11 formed thereon is placed on a heating table 12, spacers 44 are placed near the ends 6 and surrounding areas 7 of the arrayed layer 11, and the arrayed layer 11 is pressed in a direction perpendicular to the surface (Z direction) via a pressure plate 45 to form a heat dissipation coating structure 1. At this time, at the ends of the arrayed layer 11 where the spacers 44 are present, there are areas where the pressure from the pressure plate 45 is not easily transmitted due to the spacers 44. Therefore, the resin 3 particles are not easily crushed in areas where the pressure is not easily transmitted. On the other hand, the central part of the arrayed layer 11 is easily pressed. Therefore, the contact area between the resin 3 particles constituting the central part of the arrayed layer 11 and the heat dissipation particles 2 increases, resulting in the effect that the central part of the arrayed layer 11 is heated more easily than the surrounding areas.

[0037] In order to obtain the above effect, the thickness of the spacer 44, the thickness of the final heat dissipation coating structure 1, and the distance between the spacer 44 and the end 6 and surrounding area 7 of the heat dissipation coating structure 1 are adjustments that should be made within an appropriate range.

[0038] The details of each step are explained below.

[0039] [Combination Processing Process] (Figure 2(b)) As preparation for forming the powder layer, it is important to go through a step of dry stirring and mixing of particles consisting of heat-dissipating particles 2 and resin 3. Here, stirring and mixing refers to a method of mixing the heat-dissipating particles 2 and resin 3 while applying compressive and shear forces, but is not particularly limited to any other method. The purpose of this step is to coat at least a portion of the surface of the particles made of resin 3 with heat-dissipating particles 2. By applying compressive and shear forces during mixing, the adhesion is improved by partially embedding the heat-dissipating particles 2 on the surface of the resin 3 particles, and composite particles 8 are obtained in which the surface of the resin 3 particles is coated with heat-dissipating particles 2.

[0040] Furthermore, the mixing ratio of heat-dissipating particles 2 to resin 3 is, based on weight, for example, 76.9:23.1 to 45.4:54.6, preferably 66.7:33.3 to 50:50. Based on volume, it is 53.6:46.4 to 27.8:72.2, preferably 48.0:52.0 to 31.6:68.4. By keeping the mixing ratio within the above range, a heat-dissipating coating structure 1 with high heat dissipation performance and durability can be obtained.

[0041] [Powder layer formation process] (Figure 2(c)) The following is an example of the powder layer formation process in this embodiment. (1) The composite particles 8, which consist of the heat-dissipating particles 2 and resin 3 obtained in the composite processing step, are dispersed in a solvent in which the heat-dissipating particles 2 and resin 3 do not dissolve and do not undergo a chemical reaction. If necessary, a small amount of inorganic filler or binder such as pigment is dispersed to create a slurry ink, and the obtained ink is applied to the surface of the metal structure (substrate) 4 and dried to obtain a powder layer 9.

[0042] Furthermore, the method of applying the ink is not particularly limited, but examples of known application methods include blade coaters, gravure coaters, dip coaters, reverse coaters, roll knife coaters, wire bar coaters, slot die coaters, air knife coaters, curtain coaters, spray coaters, etc., or combinations thereof.

[0043] Examples of solvents used for slurry formation include water and ethanol, but the method is not limited to these; any solvent that does not chemically react with the heat-dissipating particles 2 and the resin 3 should be appropriately selected. Furthermore, during drying, any known drying method using a heater or the like, or a firing method, may be employed as long as the solvent can be removed, without any particular limitations.

[0044] (2) Another method for preparing the powder layer 9 in this embodiment 1 is as follows: A mixed powder is prepared by mixing the powdered composite particles 8 (not slurryed) with a small amount of inorganic filler or binder, such as pigment, as needed. This mixed powder is then uniformly deposited on the surface of the metal structure (substrate) 4 to form a powder layer 9. The method for uniformly depositing the mixed powder is not particularly limited, but examples include the squeegee method, where the powder is spread with a squeegee; the electrostatic coating method, where the powder is propelled by electrostatic force; the electrostatic screen method; or known methods combining these.

[0045] Here, it is important that when the powder layer 9 is formed, the heat-dissipating coating structure 1 is manufactured by depositing composite particles 8, which consist of resin 3 coated with heat-dissipating particles 2 on their surface; however, other details are not particularly limited. Hereafter, the method of forming the heat-dissipating coating structure 1 through the formation of this powder layer 9 will be referred to as "dry coating".

[0046] [Alignment Process] (Figure 2(d)) The following are examples of the arrangement process in this embodiment. The surface of the powder layer 9 formed in the powder layer formation process is pressurized and / or heated using a mold or the like, crushing the composite particles 8 and the spaces 10 while pushing out the gas (air when working in the atmosphere) present in the spaces 10 between the composite particles 8, thereby obtaining an arrayed layer 11. For productivity purposes, it is also possible to convey the powder layer 9 while pressurizing it with a pressure roller for roll-to-roll processing.

[0047] [Heat curing process] (Figure 2(e)) The heat curing process in this embodiment may be, for example, the following method. The array layer 11 formed in the array process is pressurized and / or heated using a mold or the like to soften the resin 3, filling the gaps remaining in the array layer 11 with the resin 3 and flattening the surface of the array layer 11. Finally, the resin 3 is solidified by cooling to form the heat dissipation coating structure 1. Considering productivity, it is also possible to convey the powder layer 9 while pressurizing it with a pressure roller for roll-to-roll processing. Furthermore, the heating temperature and pressurizing pressure can be set in stages over multiple steps. Furthermore, it is important to set the temperature around the edges 7 of the heat dissipation coating structure 1 lower than the internal temperature in the direction perpendicular to the surface of the heat dissipation coating structure 1 (Z direction). The purpose of this is to ensure that the resin 3 is sufficiently melted in the central part of the heat dissipation coating structure 1 to ensure adhesion with the substrate 4, while preventing the resin 3 from melting and spreading at the edges 6 or the side surfaces 5 of the edges 7. In addition, it is to maintain the shape of the side surfaces 5 with irregularities derived from the resin 3 particles remaining.

[0048] Furthermore, the end portion 6 is the intersection point where the end of the heat dissipation coating structure 1 meets the substrate 4, and the end portion periphery 7 is the region within 10 mm of the inside of the heat dissipation coating structure 1 from the end portion 6. In addition, the end portion side surface 5 refers to the surface of the heat dissipation coating structure 1 in the region of the end portion periphery 7 where the film thickness of the heat dissipation coating structure 1 becomes thinner towards the end portion 6.

[0049] <Electronic Components> In Embodiment 1, the electronic component 16 is a component having at least the heat dissipation coating structure 1 described above on its surface, as shown in the schematic cross-sectional view of Figure 4. For example, a metal structure (substrate) 4 with the heat dissipation coating structure 1 formed on its surface is used in contact with a heating device 13 (or heating element). It is also possible to omit the metal structure 4 and form the heat dissipation coating structure 1 directly on the surface of the heating device 13. Here, the heat-generating device 13 is not particularly limited as long as it generates heat, but examples include power modules and LED elements.

[0050] <Electronic equipment> In Embodiment 1, the electronic device is not particularly limited as long as it includes at least the heat dissipation coating structure 1 described above, and examples include smartphones, tablet terminals, lighting equipment, and control units for industrial equipment. For example, Figure 5 is a schematic perspective view showing an electronic device 18 according to Embodiment 1, which may consist of a heat dissipation coating structure 1, a heat-generating element 15, a substrate 4, and a tablet housing 17. Thus, this disclosure can be applied to heat dissipation applications for small, lightweight, and thin electronic devices where fans or heat sinks cannot be installed.

[0051] The specific details of the embodiments described herein will be explained below with reference to examples, but this disclosure is not limited to the following examples.

[0052] (Examples and Comparative Examples) Detailed information regarding the mixing ratio, manufacturing conditions such as set temperature, and evaluation results of the heat dissipation coating structure 1 prepared in the examples and comparative examples is shown in Table 1 of Figure 9.

[0053] (Evaluation sample) To evaluate the film durability of the heat dissipation coating structure 1, an evaluation element 22 was fabricated by forming a heat dissipation coating structure 21 measuring 40 mm x 40 mm and 0.03 to 0.08 mm in thickness on the surface of a 60 mm x 60 mm, 2 mm thick aluminum metal plate 20, according to the conditions shown in Table 1 of Figure 9, and in the configuration shown in Figure 6(a).

[0054] The specific details of the examples and comparative examples are shown below. Cordierite particles (average particle size 1.7 μm) (SS-1000: manufactured by Marusu glaze) were used as heat-dissipating particles, and resin particles made of thermosetting epoxy resin were used as the resin. Furthermore, an evaluation element 22 including the heat-dissipating coating structure 21 was fabricated according to the coating method described above and the conditions shown in Table 1 of Figure 9.

[0055] Furthermore, the temperature settings used when creating each evaluation element 22 are shown in Table 1 of Figure 9. The evaluation elements 22 were fabricated after the apparatus conditions were determined in advance to match these temperature settings. The locations where temperature measurements were taken are explained using Figure 6(b). The area where the heat dissipation coating structure 21 is formed on the aluminum metal plate 20 is shown by a dotted line. The temperature of the aluminum metal plate 20 was measured at the center of the aluminum metal plate (23 in the figure), which corresponds to the center of the heat dissipation coating structure, and at a point 15 mm from the edge of the aluminum metal plate 20 (24-27 in the figure), which corresponds to the area around the edge of the heat dissipation coating structure. For the examples and comparative examples, the temperature of the center 23 is shown as the center temperature, and the average value of the temperatures at the edges 24-27 is shown as the edge temperature in Table 1 of Figure 9.

[0056] (Comparative Example 1) For Comparative Example 1, a heat dissipation coating structure 21 was formed on an aluminum metal plate 20 using the manufacturing method shown in this embodiment, and an evaluation element 22 was fabricated. Specifically, composite particles were prepared by pre-mixing cordierite particles and resin particles of 2 to 150 μm consisting of thermosetting resin (epoxy resin: PE) (Perpowder PCE750: manufactured by Pernox). After forming a powder layer of the composite particles using the squeegee method, an array layer was formed by pressurizing the powder layer with a press machine, and the heat dissipation coating structure 21 was formed by heating the array layer on a hot plate (HP).

[0057] Here, the relationship between the HP and the evaluation element 22 was such that the entire surface of the aluminum metal plate 20 of the evaluation element 22 was in contact with the heating element of the HP, and the evaluation element 22 was fabricated. Furthermore, the temperature conditions were set to achieve the central temperature and peripheral temperature of the edges shown in Table 1 of Figure 9.

[0058] (Comparative Example 2) Next, for Comparative Example 2, an evaluation element 22 was fabricated using the same method as in Comparative Example 1. The only difference was that the blending ratio of cordierite particles to resin was changed; all other conditions were the same. The blending ratios for Comparative Example 2 are shown in Table 1 of Figure 9.

[0059] (Comparative Examples 3-4) Next, evaluation elements 22 were fabricated for Comparative Examples 3 and 4 using the same method as for Comparative Examples 1 and 2. The material mixing ratios for Comparative Examples 3 and 4 correspond to those for Comparative Examples 1 and 2, respectively, with the only difference being the temperature conditions. The set temperatures for Comparative Examples 3 and 4 are shown in Table 1 of Figure 9.

[0060] (Examples 1 and 2) In Examples 1 and 2, the evaluation element 22 was fabricated using the same procedure as in the comparative example. The difference from the comparative example is that in the heat curing process, the configuration described in Figure 3(a) was used, and the aluminum metal plate 20 was positioned on the metal block (heating stand 12) placed on the HP so that its edge protruded from the metal block. Furthermore, to ensure that the temperature at or around the edge of the aluminum metal plate 20 was lower than the temperature at the center, the temperature settings of the prototype environment and the air blowing onto the edge of the aluminum metal plate 20 were actively adjusted to vary the temperature at the center and the edges of the heat dissipation coating structure. The set temperatures in Examples 1 and 2 are shown in Table 1 of Figure 9.

[0061] (Examples 3 and 4) In Examples 3 and 4, the evaluation element 22 was fabricated using the same method as in Examples 1 and 2, with the only difference being that the temperature setting value was changed. The set temperatures in Examples 3 and 4 are shown in Table 1 of Figure 9.

[0062] (Comparative Examples 5 and 6) In Comparative Examples 5 and 6, the evaluation element 22 was fabricated using the same method as in Examples 1 and 2, with the only difference being that the temperature setting was changed. The set temperatures for Comparative Examples 5 and 6 are shown in Table 1 of Figure 9.

[0063] (Examples 5, 6) In Examples 5 and 6, the evaluation element 22 was fabricated in the same manner as in Comparative Examples 1 and 2. The difference was that in the heat curing process, the configuration described in Figure 3(b) was used, an aluminum metal plate 20 was placed on the HP (heating table 12), and spacers 14 were placed at the edges of the aluminum metal plate 20 before heating and pressing.

[0064] (Examples 7, 8) In Examples 7 and 8, the evaluation element 22 was fabricated using the same method as in Comparative Examples 5 and 6, with the only difference being that the temperature setting value was changed. The set temperatures in Examples 7 and 8 are shown in Table 1 of Figure 9.

[0065] (Examples 9, 10) In Examples 9 and 10, the evaluation element 22 was fabricated using the same method as in Examples 7 and 8, with the only difference being that the temperature setting value was changed. The set temperatures in Examples 9 and 10 are shown in Table 1 of Figure 9.

[0066] <Membrane durability evaluation> The evaluation elements 22 prepared in the comparative example and the example were heated to 150°C, then placed on a metal block at 25°C and rapidly cooled. This process was repeated 10 times to check the deterioration state of the heat dissipation coating structure, and the results are shown in Table 1 of Figure 9. The evaluation criteria are as follows.

[0067] We checked whether the heat dissipation coating structure peeled off from the aluminum metal plate in the central part of the heat dissipation coating structure. If it did not peel off, it was marked as "Central peeling ○"; if it did peel off, it was marked as "Central peeling ×". Furthermore, the strength of the heat dissipation coating structure was checked for weakness in the central part, and it was confirmed whether cracks occurred in the heat dissipation coating structure. If no cracks were found, it was marked as "central crack ○"; if cracks were found but not to the point of a full split, it was marked as "central crack △"; and if splits or cracks were found, it was marked as "central crack ×".

[0068] Next, we checked whether the heat dissipation coating structure peeled off the aluminum metal plate around the edges of the heat dissipation coating structure. If it did not peel off, we marked it as "peeling around the edges" (○), and if it did peel off, we marked it as "peeling around the edges" (×).

[0069] Furthermore, the strength of the heat dissipation coating structure was checked around the edges to see if cracks were occurring in the film. If no cracks were found, it was marked as edge cracks (○); if cracks were found but not to the point of full-blown fissures, it was marked as edge cracks (△); and if cracks or fissures were found, it was marked as edge cracks (×).

[0070] <Results and Discussion of the Examples> First, in Comparative Examples 1 and 2, it was confirmed that the heat-dissipating coating structure peeled off from the aluminum metal plate from the central part. On the other hand, as in Comparative Examples 3 and 4, by setting a higher temperature when forming the heat-dissipating coating structure, peeling in the central part of the heat-dissipating coating structure was eliminated, but it was confirmed that cracks occurred on the side edges.

[0071] Furthermore, by setting the temperature around the edges lower than in Comparative Examples 3 and 4, as in Examples 1 and 2, crack formation around the edges and on the sides of the edges was suppressed.

[0072] This result will be explained using Figure 7. First, in Comparative Examples 1 and 2, the temperature was low, and the resin 3 did not melt sufficiently and hardened. As a result, as shown in Figure 7(b), the adhesion force at the interface with the aluminum metal plate (substrate) 4 was not sufficiently maintained, and the resin hardened and shrank, leaving residual stress at the interface (Y in the figure). In Comparative Examples 3 and 4, as shown in Figure 7(c), the resin 3 melted sufficiently, and the adhesion force at the interface with the aluminum metal plate was secured, thus eliminating delamination in the central part. However, at the edges and side surfaces around the edges, the resin 3 melted and flowed out. The flowed-out portion (Z in the figure) has a high proportion of resin 3 and a low content of cordierite particles. In other words, because there are fewer cordierite particles to disperse and relieve stress, the stress during heat curing is concentrated and remains on the side surfaces 5 and around the edges 7, making delamination more likely.

[0073] Therefore, by setting the temperature around the edges lower than the temperature in the central part, as in Examples 1 and 2, we believe that we were able to achieve the effect of resolving both the defects in the central part (Figure 7(b)) and the side edges (Figure 7(c)) as described above, as shown in Figure 7(a).

[0074] Furthermore, when the temperature setting around the edges is lowered, as in Examples 3 and 4 and Comparative Examples 5 and 6, similar effects to Examples 1 and 2 are obtained in Examples 3 and 4, but in Comparative Examples 5 and 6, the temperature around the edges becomes too low, resulting in a decrease in adhesion around the edges. This indicates that an appropriate temperature range exists.

[0075] What is important here is that, around the edges of the heat-dissipating coating structure 1, the resin 3 must partially melt while hardening and maintaining adhesion to the aluminum metal plate. On the other hand, it is desirable that the resin 3 does not completely melt and flow out onto the side surface of the edge, but that some of the resin 3 particles remain, leaving irregularities on the side surface. This is because the irregularities absorb and diffuse the stress caused by thermal expansion and contraction, and therefore, the above-mentioned appropriate temperature range is considered to exist.

[0076] Furthermore, in the heat dissipation coating structure 1 created in this embodiment, the film thickness of the heat dissipation coating structure 1 was 88 μm on average in plane, and the maximum value of the irregularities caused by the resin 3 particles on the side surfaces of the end portions of the heat dissipation coating structure was between 2.8 μm and 45 μm. Controlling the melting state of the resin 3 on these side surfaces within an appropriate range is important for the durability of the heat dissipation coating structure, and it is desirable to set the maximum value of the irregularities on the side surfaces of the end portions to be between 1 / 30 and 1 / 2 of the film thickness of the heat dissipation coating structure.

[0077] Next, in Examples 5 and 6, as shown in Figure 3(b), when forming the heat-dissipating coating structure 1, it was confirmed that the decrease in adhesion in the central part that occurred in Comparative Examples 1 and 2 was improved by placing spacers around the edges and near the side surfaces of the heat-dissipating coating structure 1 and pressing while heating. This is thought to be because the contact points between the resin 3 and the heat-dissipating particles 2 increased even at low temperatures in the central part, making the resin 3 easier to melt, which promoted adhesion with the aluminum metal plate and suppressed peeling in the central part.

[0078] Furthermore, it was confirmed that pressing as in Examples 7 and 8 improved the peeling around the edges that occurred in Comparative Examples 5 and 6. This is thought to be because the contact points between the resin 3 and the heat-dissipating particles 2 increased even at low temperatures around the edges, making the resin 3 easier to melt, which promoted adhesion with the aluminum metal plate and suppressed peeling around the edges.

[0079] Furthermore, by using a combination of heating and pressurization as in Examples 9 and 10, it is possible to lower the temperature setting in the central part compared to Examples 7 and 8, which is another advantage. Due to the equipment configuration, there is a need to avoid creating a large temperature difference between the central part and the edges from the standpoint of equipment load and energy consumption. Therefore, the pressing method of installing spacers near the edges and side surfaces of the heat dissipation coating structure 1, as in Examples 9 and 10, is effective.

[0080] Furthermore, the effects described in this embodiment are similar when the mixing ratio of cordierite particles to the three resin particles is in the range of 66.7:33.3 to 50.0:50.0 by weight and 48.0 to 52.0 to 31.6 to 68.4 by volume, and are effective at least within this range.

[0081] Furthermore, this disclosure includes appropriately combining any of the various embodiments and / or examples described above, and the effects of each embodiment and / or example can be achieved. [Industrial applicability]

[0082] The heat dissipation coating structure according to this disclosure can provide a member having the heat dissipation coating structure on its surface. Furthermore, it can provide an electronic member including such a member, and an electronic device including such an electronic member. [Explanation of Symbols]

[0083] 1 Heat dissipation coating structure 2 Heat dissipating particles 3 Resin 4 Base material (metal structure) 5 End side 6 End 7. Around the edges 8 Composite particles 9 Powder layer 10 Space 11 Array Layers 12 Heating table 13 Heating devices 15 Heating element 16 Electronic Components 17 Tablet enclosure 18 Electronic equipment 20 Aluminum metal plates 21 Heat dissipation coating structure 22 Evaluation 43. Airflow 44 Spacer 45 Pressure Plate

Claims

1. A heat-dissipating coating structure having heat-dissipating particles and resin, The heat-dissipating particles are particles with an average particle diameter of 0.1 to 30 μm, composed of an oxide containing at least two elements selected from the group consisting of aluminum, magnesium, and silicon. The average thickness of the heat-dissipating coating structure is 10 times or more the average particle diameter of the heat-dissipating particles. A heat-dissipating coating structure having irregularities due to the resin on the end side surface of the heat-dissipating coating structure, wherein the heat-dissipating particles are present on the surface of the irregularities.

2. The heat dissipation coating structure according to claim 1, wherein the maximum difference in the unevenness due to the resin is 1 / 30 or more and 1 / 2 or less of the average film thickness of the heat dissipation coating structure.

3. The heat dissipation coating structure according to claim 1, wherein the resin is selected from the group consisting of epoxy resin, epoxy polyester resin, polyester resin, and acrylic resin.

4. An electronic component having a heating element, The heat dissipation coating structure according to any one of claims 1 to 3, which is arranged in direct or indirect contact with the heating element, Electronic components, including those mentioned above.

5. Electronic equipment having a heating element, The heat dissipation coating structure according to any one of claims 1 to 3, which is arranged in direct or indirect contact with the heating element, Electronic devices, including those mentioned above.

6. A method for manufacturing a heat-dissipating coating structure, comprising forming a heat-dissipating coating structure having heat-dissipating particles and a resin on the surface of a substrate, A compounding process is performed to form composite particles in which the heat-dissipating particles are coated on the surface of particles made of the resin, A film formation step in which a powder film is formed by stacking the aforementioned composite particles, A heat curing step in which the powder film is heated and the resin is heated and cured, Includes, A method for manufacturing a heat-dissipating coating structure, comprising the thermosetting step, wherein the temperature around the edge of the heat-dissipating coating structure on the surface of the substrate is made lower than the temperature in areas other than the edge.

7. In the aforementioned heat curing process, when solidifying the heat dissipation coating structure under pressure, the pressure applied around the edges of the heat dissipation coating structure is made weaker than in areas other than the edges. A method for manufacturing a heat dissipation coating structure according to claim 6.

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