Thermally conductive resin composition and thermally conductive resin material

Abstract

To provide a thermally conductive resin composition which can have improved thermal conductivity while being inhibited from having an increased viscosity.SOLUTION: A thermally conductive resin composition comprises a first resin phase, a second resin phase, and a thermally conductive filler. The first resin phase and the second resin phase are separate from each other. The thermally conductive filler is present in the first resin phase in a higher density than in the second resin phase. Since the thermally conductive filler is present more in the first resin phase than in the second resin phase, the particles of the thermally conductive filler are more apt to be in contact with each other than in the case where the thermally conductive filler is dispersed equally in the first resin phase and the second resin phase.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a thermally conductive resin composition and a thermally conductive resin material. More specifically, it relates to a thermally conductive resin composition and a thermally conductive resin material containing a thermally conductive filler. Background Art

[0002] Patent Document 1 describes a thermally conductive silicone rubber composition. In this thermally conductive silicone rubber composition, a thermally conductive inorganic filler surface-treated with a specific silane coupling agent is dispersed in silicone rubber. Thereby, even when the thermally conductive inorganic filler is highly filled, flexibility and heat-resistant mechanical properties are imparted to the molded article. Prior Art Documents Patent Documents

[0003] Patent Document 1 Japanese Unexamined Patent Publication No. 11-209618 Summary of the Invention Problems to be Solved by the Invention

[0004] Generally, in order to improve the thermal conductivity of a thermally conductive silicone rubber composition and a molded article thereof, a thermally conductive inorganic filler is highly filled (the filling amount is increased) in the silicone rubber. However, when the thermally conductive inorganic filler is highly filled, the viscosity of the thermally conductive silicone rubber composition tends to increase, which causes problems that the thermally conductive silicone rubber composition is difficult to apply and it is difficult to form a molded article having a desired thickness.

[0005] An object of the present disclosure is to provide a thermally conductive resin composition and a thermally conductive resin material that can improve thermal conductivity while suppressing an increase in viscosity. Means for Solving the Problems

[0006] A thermally conductive resin composition according to one aspect of the present disclosure comprises a first resin phase, a second resin phase, and a thermally conductive filler. The first resin phase and the second resin phase are phase-separated. The density of the thermally conductive filler in the first resin phase is higher than the density of the thermally conductive filler in the second resin phase. The aforementioned thermally conductive filler contains spinel particles.

[0007] A thermally conductive resin material according to one aspect of the present disclosure is a solidified product of the thermally conductive resin composition, comprising a solid phase of the first resin phase, a solid phase of the second resin phase, and the thermally conductive filler. [Effects of the Invention]

[0008] According to this disclosure, since the thermally conductive filler is more unevenly distributed in the first resin phase than in the second resin phase, the particles of the thermally conductive filler are more likely to come into contact with each other compared to when the thermally conductive filler is evenly dispersed in both the first and second resin phases. Therefore, thermal conductivity can be improved even with a small amount of thermally conductive filler, and the increase in viscosity can also be suppressed because the amount of thermally conductive filler is small. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1A is a model diagram showing an example of a phase separation structure between the first and second resin phases. Figure 1B is a model diagram showing an example of a dispersion structure of a thermally conductive filler in the first and second resin phases. [Figure 2] Figure 2A is a model diagram showing another example of the phase separation structure between the first and second resin phases. Figure 2B is a model diagram showing another example of the dispersion structure of the thermally conductive filler in the first and second resin phases. [Figure 3] Figure 3A is a model diagram showing another example of the phase separation structure between the first and second resin phases. Figure 3B is a model diagram showing another example of the dispersion structure of the thermally conductive filler in the first and second resin phases. [Modes for carrying out the invention]

[0010] 1. Overview The thermally conductive resin composition according to this embodiment includes a first resin phase, a second resin phase, and a thermally conductive filler. The first and second resin phases are phase-separated, forming a multiphase system. The density of the thermally conductive filler in the first resin phase is higher than the density of the thermally conductive filler in the second resin phase. That is, the amount of thermally conductive filler particles contained in the first resin phase per unit volume is greater than the amount of thermally conductive filler particles contained in the second resin phase per unit volume. Therefore, if the amount of thermally conductive filler relative to the total amount of the first and second resin phases is constant, the thermally conductive filler particles are more likely to come into contact with each other when the thermally conductive filler is predominantly concentrated in the first resin phase rather than the second resin phase (in the case of the thermally conductive resin composition of this embodiment) compared to when the thermally conductive filler is evenly dispersed in both the first and second resin phases. Thus, the thermally conductive resin composition of this embodiment can improve thermal conductivity even with a small amount of thermally conductive filler. Furthermore, the thermally conductive resin composition of this embodiment suppresses the increase in viscosity because it contains a small amount of thermally conductive filler.

[0011] The thermally conductive resin material according to this embodiment is a solidified product of the thermally conductive resin composition according to this embodiment, and includes a solid phase of a first resin phase, a solid phase of a second resin phase, and a thermally conductive filler. In the thermally conductive resin material of this embodiment, as with the thermally conductive resin composition, the thermally conductive filler is unevenly distributed, with more of it in the first resin phase than in the second resin phase. Therefore, the particles of the thermally conductive filler are more likely to come into contact with each other compared to when the thermally conductive filler is evenly dispersed in both the first and second resin phases. Thus, the thermally conductive resin material of this embodiment can improve thermal conductivity even with a small amount of thermally conductive filler.

[0012] 2.Details 2-1. Thermally conductive resin composition The thermally conductive resin composition according to this embodiment comprises a first resin phase, a second resin phase, and a thermally conductive filler 3.

[0013] As shown in Figures 1A, 2A, and 3A, the first resin phase 1 and the second resin phase 2 have a phase separation structure. That is, the first resin phase 1 and the second resin phase 2 have low compatibility and are in a separated state. Figure 1A shows the sea-island structure of the first resin phase 1 and the second resin phase 2. That is, it shows a structure in which multiple second resin phases 2 are scattered within the first resin phase 1. Figure 2A shows the interconnected structure of the first resin phase 1 and the second resin phase 2. That is, it shows a structure in which the first resin phase 1 and the second resin phase 2 are interconnected in an interwoven state. Figure 3A shows the layered structure of the first resin phase 1 and the second resin phase 2. That is, it shows a structure in which the first resin phase 1 and the second resin phase 2 are each layered and arranged alternately.

[0014] The first resin phase 1 is composed of the first resin. The first resin is fluid and is either liquid or paste-like. The second resin phase 2 is composed of the second resin. The second resin is fluid and is either liquid or paste-like. The first and second resins are different types of resins. That is, the solubility parameter (SP value) of the first resin and the solubility parameter of the second resin are different. In this embodiment, it is preferable that the difference between the solubility parameter of the first resin and the solubility parameter of the second resin is 1 or more. This results in lower compatibility between the first and second resins compared to the case where the difference between the solubility parameter of the first resin and the solubility parameter of the second resin is less than 1, making it easier for the first resin phase 1 and the second resin phase 2 to form a phase separation structure. Since it is preferable for the difference between the solubility parameter of the first resin and the solubility parameter of the second resin to be large, no upper limit is particularly set.

[0015] Any type of resin can be used as the first and second resins, as long as they form a phase separation structure. For example, a thermosetting resin can be used as the first resin. This thermosetting resin is uncured, for example, an uncured liquid epoxy resin can be used. An example of such an epoxy resin is bisphenol A type epoxy resin. As the second resin, for example, a thermoplastic resin can be used. This thermoplastic resin is in a liquid state, such as by melting, and examples include polyethersulfone, silicone resin, acrylic resin, and urethane resin. Among these, it is preferable to use bisphenol A type epoxy resin and polyethersulfone, which readily forms a phase separation structure. The first and second resins may each contain appropriate solvents for purposes such as viscosity adjustment. The ratio of the first and second resins is not particularly limited as long as a phase separation structure of first resin phase 1 and second resin phase 2 can be formed, but for example, it is in the range of 95:5 to 30:70 by weight ratio, and more preferably 90:10 to 50:50. If the amount of the first resin is excessively high and the amount of the second resin is too low, the first resin phase 1 will approach a single-layer state, making it impossible to obtain a suitable phase separation structure. Also, if the amount of the first resin decreases, the proportion of the first resin phase 1 will also decrease, and if the amount of the first resin phase 1 becomes excessively low, the effect of improving thermal conductivity through the phase separation structure may not be fully obtained. Furthermore, if the amount of the first resin decreases, the thermal conductive fillers unevenly distributed within the first resin phase 1 are more likely to become saturated, and the excess thermal conductive fillers will enter the second resin phase 2, potentially causing the effect of improving thermal conductivity through the phase separation structure to plateau.

[0016] The thermally conductive filler 3 is an aggregate of particles capable of conducting heat. The thermally conductive filler 3 has higher thermal conductivity than the first resin phase 1 and the second resin phase 2. In other words, the thermally conductive filler 3 has lower thermal resistance than the first resin phase 1 and the second resin phase 2. The particles constituting the thermally conductive filler 3 preferably contain inorganic materials such as alumina and spinel. In this case, the thermal conductivity of the thermally conductive filler 3 tends to be higher compared to when particles containing organic materials are used.

[0017] Preferably, the thermally conductive filler 3 contains polyhedral particles. The polyhedral particles are particles whose cross-sectional shape is a polygon such as a hexagon or an octagon, and it is preferable that the outer surface of the polyhedral particles has a plurality of flat surfaces. The shape of the polyhedral particles can be confirmed with a scanning electron microscope (SEM). If, for example, 5 or more and 150 or less faces are confirmed in the polyhedral particles observed with an electron microscope, the particles can be determined to be polyhedral. Compared with spherical particles, polyhedral particles can increase the contact area between adjacent particles. Accordingly, thermal conductivity between particles is improved. Therefore, the thermal resistance of the thermally conductive resin composition and the thermally conductive resin material is easily reduced.

[0018] In the distribution curve of the number of polyhedral particles versus the number of faces of the particles, it is preferable that the maximum peak is located at a position where the number of faces of the polyhedral particles is 8 or more and 40 or less. In this case, the thermal resistance of the thermally conductive resin material can be particularly effectively reduced. This is considered to be because when the number of faces of the particles is 14 or more and 25 or less, both the likelihood of contact between particles and the size of the contact area are increased in a well-balanced manner, thereby particularly facilitating thermal conduction between particles. It is more preferable that the maximum peak is located at a position where the number of faces of the particles is 14 or more and 25 or less, and it is particularly preferable that the maximum peak is located at a position where the number of faces of the particles is 14 or more and 18 or less. Further, the closer the maximum peak is to a position where the number of faces of the particles is 16, the more preferable it is.

[0019] Preferably, the thermally conductive filler 3 is an alumina filler having an α-phase conversion rate of 80% or more. In this case, the thermal resistance of the thermally conductive resin material can be effectively reduced. This is considered to be because polyhedral particles easily come into surface contact with each other in the thermally conductive resin material, so that the heat transfer efficiency between particles tends to be high. In addition, it is considered that when the α-phase conversion rate of the alumina filler is 80% or more, the filler easily has high thermal conductivity, and accordingly, the heat transfer efficiency through the polyhedral particles tends to be further increased. The α-phase conversion rate is more preferably 110% or more, and still more preferably 120% or more.

[0020] The α-phase conversion rate of the alumina filler is calculated from the diffraction spectrum of the alumina filler obtained using a powder X-ray diffractometer, based on the peak height of the alumina α-phase appearing at 2θ=25.6° (I25.6) and the peak height of the γ-phase, η-phase, χ-phase, κ-phase, θ-phase and δ-phase appearing at 2θ=46° (I46), by the formula I25.6 / (I25.6+I46)×100(%).

[0021] The thermal conductivity of the thermally conductive filler 3 is preferably 30 W / m·K or more. In this case, the thermal resistance of the thermally conductive resin material can be particularly effectively reduced. Such high thermal conductivity of thermally conductive filler 3 can be achieved by the high α-phase conversion rate of the alumina filler.

[0022] The average particle diameter of the thermally conductive filler 3 is preferably, for example, 1 µm or more and 100 µm or less. The average particle diameter of the thermally conductive filler 3 is the median diameter (D50) calculated from the particle size distribution obtained by dynamic light scattering method.

[0023] In the thermally conductive resin composition of the present embodiment, the thermally conductive filler 3 is unevenly distributed more in the first resin phase 1 than in the second resin phase 2. That is, more particles of the thermally conductive filler 3 are present in the first resin phase 1 than in the second resin phase 2. For example, as shown in FIG. 1B, FIG. 2B and FIG. 3B, there is also a form in which all of the thermally conductive filler 3 contained in the thermally conductive resin composition is present in the first resin phase 1, and is not present at all in the second resin phase 2. When the thermally conductive filler 3 is unevenly distributed more in the first resin phase 1 than in the second resin phase 2 in this manner, compared with the case where the thermally conductive filler 3 is dispersed in both the first resin phase 1 and the second resin phase 2, the density (packing density) of the particles of the thermally conductive filler 3 in the first resin phase 1 becomes higher. Accordingly, adjacent particles of the thermally conductive filler 3 are more likely to come into contact, and the contact area between adjacent particles of the thermally conductive filler 3 increases or the contact pressure increases. Therefore, the thermal conductivity provided by the thermally conductive filler 3 is improved.

[0024] It is preferable that more than half of the thermal conductive filler 3 contained in the thermal conductive resin composition is unevenly distributed in the first resin phase 1, and it is more preferable that 60% or more of the thermal conductive filler 3 is unevenly distributed in the first resin phase 1. Alternatively, all (100%) of the thermal conductive filler 3 contained in the thermal conductive resin composition may be unevenly distributed in the first resin phase 1.

[0025] The thermally conductive filler 3 tends to be more readily dispersed in the first resin phase 1 than in the second resin phase 2 if it is more compatible with the first resin phase 1 than in the second resin phase 2. In other words, the surface properties of the particles of the thermally conductive filler 3 make it more likely to be preferentially dispersed in the first resin phase 1 than in the second resin phase 2. For example, if the surface of the particles of the thermally conductive filler 3 has components (such as functional groups) that are more compatible with the first resin phase 1 than with the second resin phase 2, the thermally conductive filler 3 will disperse more easily in the first resin phase 1 than in the second resin phase 2, and thus become more preferentially dispersed. Therefore, the thermally conductive filler 3 may be treated with a coupling agent. When the thermally conductive filler 3 is treated with a coupling agent, it disperses well in the first resin phase 1 in the thermally conductive resin composition and thermally conductive resin material, and as a result, the thermal resistance of the thermally conductive resin material is easily reduced.

[0026] The proportion of thermal conductive filler 3 is preferably 60% by volume or more of the total thermal conductive resin composition. When this proportion is 60% by volume or more, the thermal resistance of the thermal conductive resin material is particularly easily reduced. It is more preferable that the proportion of thermal conductive filler is 70% by volume or more. In this case, the thermal resistance of the thermal conductive resin material is further easily reduced. It is also preferable that the proportion of thermal conductive filler 3 is 80% by volume or less. In this case, the thermal conductive resin composition tends to have good fluidity, and the thermal conductive resin material tends to have good flexibility.

[0027] The thermally conductive resin composition is preferably liquid or paste-like at 25°C. The viscosity of the thermally conductive resin composition at 25°C is preferably 3000 Pa·s or less. In this case, the thermally conductive resin composition can have good moldability, making it easier to mold into film, sheet, or plate shapes using a dispenser, for example. Furthermore, the thermally conductive resin composition is easy to degas, thus reducing the likelihood of void formation in the thermally conductive resin material. The viscosity is measured using an E-type rotational viscometer at a speed of 0.3 rpm.

[0028] A thermally conductive resin composition is prepared, for example, by kneading a first resin, a second resin, and a thermally conductive filler 3. In this case, the ratio (volume ratio) of the first resin to the second resin is preferably 1:9 to 9:1. With such a ratio, it is easy to obtain a thermally conductive resin composition and a thermally conductive resin material having the desired properties described above. For example, it is preferable that the first resin phase 1 is formed without interruption, so that multiple particles of the thermally conductive filler 3 are in contact with each other and are unevenly distributed within the first resin phase 1. However, if there is too much of the first resin phase 1, the thermally conductive filler 3 may be diffused too much within the first resin phase 1, making it difficult for multiple particles of the thermally conductive filler 3 to come into contact with each other. Taking these points into consideration, the ratio of the first resin constituting the first resin phase 1 and the second resin constituting the second resin phase 2 is set. A more preferable ratio (volume ratio) of the first resin to the second resin is 8:2 to 3:7. Furthermore, the first resin phase 1 does not necessarily have to be formed without interruption; it may be interrupted like an island in a sea-island structure. In this case, the thermally conductive filler 3 is unevenly distributed in the portion of the first resin phase 1, which can improve the thermal conductivity of the thermally conductive resin composition and the thermally conductive resin material.

[0029] 2-2. Thermally conductive resin materials The thermally conductive resin material according to this embodiment is a solidified product of the thermally conductive resin composition according to this embodiment. That is, the thermally conductive resin material of this embodiment includes a solid phase of a first resin phase 1, a solid phase of a second resin phase 2, and a thermally conductive filler 3. The solid first resin phase 1 is a solidified product of the first resin phase 1 that was in the liquid phase in the thermally conductive resin composition. The solid second resin phase 2 is a solidified product of the second resin phase 2 that was in the liquid phase in the thermally conductive resin composition. If the liquid first resin phase 1 is an uncured thermosetting resin, the solid first resin phase 1 is composed of a thermosetting resin that has been thermoset. The thermosetting resin may be cured using a curing agent. If the liquid second resin phase 2 is a thermoplastic resin, the solid second resin phase 2 is composed of a thermoplastic resin that has been solidified by low temperature. The thermally conductive filler 3 is more abundant in the solid first resin phase 1 than in the solid second resin phase 2. The thermally conductive filler 3 is further pressed against the first resin phase 1 by the stress generated when the first resin phase 1 and the second resin phase 2 solidify. Therefore, the thermally conductive filler 3 is more unevenly distributed in the first resin phase 1 when using a thermally conductive resin material than when using a thermally conductive resin composition.

[0030] When producing a thermally conductive resin material from a thermally conductive resin composition, for example, the thermally conductive resin composition is molded into a film, sheet, or plate shape by an appropriate method such as press molding, extrusion molding, or calendering. It is also preferable to mold the thermally conductive resin composition into a film shape using a dispenser. After this, the thermally conductive resin material is obtained by curing the film-shaped thermally conductive resin composition by heating it under conditions appropriate to its composition.

[0031] Thermally conductive resin materials tend to have low thermal resistance due to the inclusion of thermally conductive filler 3. This is thought to be because, as mentioned above, the contact between the particles of thermally conductive filler 3 within the thermally conductive resin material forms pathways that can transfer heat, and the ease with which these particles make surface contact increases the efficiency of heat transfer between particles.

[0032] When a press pressure is applied to a thermally conductive resin material, the thermal resistance of the thermally conductive resin material tends to be particularly low in the direction of the press pressure. This is thought to be because the particles of the thermally conductive filler 3 tend to come into contact with each other in the direction of the press pressure. In this embodiment, as described above, the particles tend to come into surface contact with each other, so the reduction in thermal resistance due to the application of press pressure is particularly likely to occur, and the thermal resistance can be reduced even with a small press pressure.

[0033] In this embodiment, the thermally conductive resin material has a lower thermal resistance as described above, and it is preferable that the thermal resistance of the thermally conductive resin material in the direction of the press pressure is 0.8 K / W or less when directly pressed at a press pressure of 1 MPa. In this case, the thermally conductive resin material can exhibit excellent thermal conductivity and efficiently transfer heat even at low press pressures. This thermal resistance is more preferably 0.7 K / W or less, and even more preferably 0.6 K / W or less.

[0034] In Figures 1B and 2B, the particles of the thermally conductive filler 3 are arranged in multiple chains within the first resin phase 1 between the second resin phases 2. In Figure 3B, the particles of the thermally conductive filler 3 are arranged in multiple chains in the vertical direction (for example, in the thickness direction of the sheet-like thermally conductive resin material) within the first resin phase 1 between the second resin phases 2.

[0035] The thermally conductive resin composition according to this embodiment can be used as a heat dissipation paste. Furthermore, the thermally conductive resin material according to this embodiment can be used as a heat dissipation sheet. The heat dissipation paste and heat dissipation sheet are, for example, placed between a chip component and a heat sink to facilitate the conduction of heat generated by the chip component to the heat sink.

[0036] 3. Variant The above describes a case where the thermally conductive resin composition consists of two types of resin phases, a first resin phase and a second resin phase. However, the thermally conductive resin composition may also be composed of three or more types of resin phases. In this case, the thermally conductive resin material is composed of three or more types of resin phases. For example, a resin phase containing a different type of thermosetting resin than the first resin phase may be used in combination, or a resin phase containing a different type of thermoplastic resin than the second resin phase may be used in combination.

[0037] The above describes the case in which one type of thermally conductive filler 3 is used, but the thermally conductive resin composition and thermally conductive resin material are not limited to this, and may be composed of two or more types of thermally conductive filler 3. For example, multiple types of thermally conductive filler 3 with different particle sizes may be included in the thermally conductive resin composition and thermally conductive resin material, multiple types of thermally conductive filler 3 with different components may be included in the thermally conductive resin composition and thermally conductive resin material, or multiple types of thermally conductive filler 3 with different particle cross-sectional shapes may be included in the thermally conductive resin composition and thermally conductive resin material. Specifically, at least one selected from the group consisting of metal oxide particles, metal nitride particles, metal carbide particles, metal boride particles, and elemental metal particles may be used as the thermally conductive filler 3. [Examples]

[0038] A thermally conductive resin composition was prepared using the following components.

[0039] • First resin: Epoxy resin (Bisphenol A type epoxy resin, manufactured by JER Corporation, using a combination of Epicote 828 and Epicote 834, SP value 13.5) • Second resin: Polyethersulfone (Victrex 5003P, manufactured by ICI, SP value 12.5) • Hardener (4,4'-methylenedianiline, manufactured by Tokyo Chemical Industry Co., Ltd.) • Thermally conductive filler: A polyhedral filler containing 80% by mass of molybdenum-doped polyhedral spinel particles with an average particle size of 70 μm, 10% by mass of molybdenum-doped polyhedral spinel particles with an average particle size of 10 μm, and 5% by mass of polyhedral alumina particles (manufactured by Sumitomo Chemical Co., Ltd.) with an average particle size of 0.4 μm. The remainder (5% by mass) consists of the first resin and the second resin.

[0040] The above components were kneaded in the proportions shown in Table 1 to obtain a thermally conductive resin composition. The thermally conductive filler content is the ratio of thermally conductive filler to the total amount of the thermally conductive resin composition (total amount of the first resin, second resin, curing agent, and thermally conductive filler).

[0041] The viscosity of the thermally conductive resin composition was then measured using an E-type viscometer (model number RC-215) manufactured by Toki Sangyo Co., Ltd., under conditions of 0.3 rpm.

[0042] Furthermore, a sheet-like sample with a thickness of 100 μm was prepared by hot-pressing a thermally conductive resin composition at a heating temperature of 150°C and a press pressure of 1 MPa for 2 hours. This sample was sandwiched between two copper plates and directly pressed with these plates at a press pressure of 1 MPa. In this state, the thermal resistance of the sample in the direction of the press pressure at room temperature was measured using a DynTIM Tester manufactured by Mentor Graphics.

[0043] [Table 1]

[0044] Comparing Example 1 with Comparative Example 1, Example 1 was able to reduce the thermal resistance value despite having the same filler content. Comparing Example 2 with Comparative Example 2, Example 2 was able to reduce the thermal resistance value and also have a lower viscosity despite having the same filler content. Comparing Example 3 with Comparative Example 3, Example 3 was able to reduce the thermal resistance value and also have a lower viscosity despite having the same filler content. [Industrial applicability]

[0045] The thermally conductive resin composition of this embodiment can be used as a heat dissipation paste. The thermally conductive resin material of this embodiment can also be used as a heat dissipation sheet. The heat dissipation paste and heat dissipation sheet are placed, for example, between electronic and electrical components such as transistors and computer CPUs (central processing units) and a heat sink. The heat dissipation paste and heat dissipation sheet then conduct the heat generated from the electronic and electrical components to the heat sink. [Explanation of Symbols]

[0046] 1 1st resin phase 2 Second resin phase 3. Thermally conductive fillers

Claims

1. It comprises a first resin phase, a second resin phase, and a thermally conductive filler. The first resin phase and the second resin phase are phase-separated. The density of the thermally conductive filler in the first resin phase is higher than the density of the thermally conductive filler in the second resin phase. The aforementioned thermally conductive filler contains spinel particles. Thermally conductive resin composition.

2. The difference between the solubility parameter of the first resin constituting the first resin phase and the solubility parameter of the second resin constituting the second resin phase is 1 or more. The thermally conductive resin composition according to claim 1.

3. The first resin phase includes a thermosetting resin, The second resin phase includes a thermoplastic resin. The thermally conductive resin composition according to claim 1 or 2.

4. The first resin phase comprises an epoxy resin. The second resin phase contains polyethersulfone. A thermally conductive resin composition according to any one of claims 1 to 3.

5. The aforementioned thermally conductive filler includes polyhedral particles. A thermally conductive resin composition according to any one of claims 1 to 4.

6. A solidified product of a thermally conductive resin composition according to any one of claims 1 to 5, The solid phase of the first resin phase, the solid phase of the second resin phase, and the thermally conductive filler are included. Thermally conductive resin material.

Images