Heat dissipation filler, resin composition, and resin molded body

Abstract

A heat dissipation filler according to the present invention is used in the production of a resin molded body, and is characterized by comprising: first thermally conductive particles having a particle diameter of 10-150 μm; second thermally conductive particles having a particle diameter of at least 0.1 μm and less than 10 μm; and fibrous aluminum nitride 1, wherein when the total amount of the first thermally conductive particles, the second thermally conductive particles, and the fibrous aluminum nitride is 100 parts by volume, the first thermally conductive particles are contained in a proportion of 30-80 parts by volume, the second thermally conductive particles are contained in a proportion of 5-50 parts by volume, and the fibrous aluminum nitride is contained in a proportion of 1-40 parts by volume.

Description

Heat-dissipating filler, resin composition, and resin molded body

[0001] The present invention relates to a heat-dissipating filler, a resin composition, and a resin molded article.

[0002] Aluminum nitride (AlN) is an insulator with high thermal conductivity, and is therefore used as an insulating heat dissipation material for electronic devices. For example, AlN sintered bodies obtained by sintering AlN have a thermal expansion coefficient similar to that of silicon (Si), making them suitable for use as heat sinks or substrates for silicon-based semiconductor devices. Meanwhile, the use of particle-dispersed composite materials, such as resin molded bodies containing dispersed AlN particles, has also been proposed.

[0003] Adding insulating fillers such as spherical ceramics is known as a method for improving the thermal conductivity of resin parts. To improve thermal conductivity, it is important to increase the contact efficiency between the fillers and form a network (heat dissipation path).

[0004] For example, as a resin molding that combines thermal conductivity and moldability, a resin molding has been proposed that contains anisotropically shaped AlN filler, in which AlN single crystal particles are fused together to form fibers, together with isotropically shaped particles (see, for example, Patent Document 1).

[0005] Furthermore, a resin composition made of an epoxy resin or a silicone resin containing AlN whiskers has been proposed, which suppresses the inclusion of impurities and thus the decrease in thermal conductivity (see, for example, Patent Document 2).

[0006] In these resin moldings, by dispersing high aspect ratio AlN whiskers in the resin molding so that they are oriented in random directions along their length, the contact density between the AlN whiskers can be increased, thereby imparting high thermal conductivity to the resin molding.

[0007] However, it has been difficult to sufficiently suppress the overall thermal resistance. Also, for example, when a resin molded body is formed into a sheet, even if the in-plane thermal conductivity is excellent, it has not been possible to achieve sufficiently excellent thermal conductivity in the thickness direction.

[0008] JP 2010-235842 A JP 2016-145120 A

[0009] The object of the present invention is to provide a heat dissipating filler that can reduce overall thermal resistance and can be suitably used for producing resin molded bodies that have excellent thermal conductivity not only in the in-plane direction but also in the thickness direction; to provide a resin composition that can be suitably used for producing resin molded bodies that can reduce overall thermal resistance and have excellent thermal conductivity not only in the in-plane direction but also in the thickness direction; and to provide a resin molded body that can reduce overall thermal resistance and has excellent thermal conductivity not only in the in-plane direction but also in the thickness direction.

[0010] These objects are achieved by the present inventions (1) to (12) below: (1) A thermally conductive filler used in the production of a resin molded body, comprising: first thermally conductive particles having a particle size of 10 μm or more and 150 μm or less; second thermally conductive particles having a particle size of 0.1 μm or more and less than 10 μm; and fibrous aluminum nitride, wherein, when the total amount of the first thermally conductive particles, the second thermally conductive particles, and the fibrous aluminum nitride is taken as 100 parts by volume, the thermally conductive filler contains the first thermally conductive particles in an amount of 30 parts by volume or more and 80 parts by volume or less, the second thermally conductive particles in an amount of 5 parts by volume or more and 50 parts by volume or less, and the fibrous aluminum nitride in an amount of 1 part by volume or more and 40 parts by volume or less.

[0011] (2) The thermally conductive filler according to (1) above, wherein the first thermally conductive particles contain at least one selected from the group consisting of aluminum nitride, boron nitride, and alumina.

[0012] (3) The heat-dissipating filler according to (1) or (2) above, wherein the second thermally conductive particles contain at least one selected from the group consisting of aluminum nitride, alumina, and silica.

[0013] (4) The heat-dissipating filler according to any one of (1) to (3) above, wherein the length of the fibrous aluminum nitride in the major axis direction is 1.0 μm or more and 5.0 cm or less.

[0014] (5) The heat-dissipating filler according to any one of (1) to (4) above, wherein the length of the fibrous aluminum nitride in the minor axis direction is 0.5 μm or more and 50.0 μm or less.

[0015] (6) The heat-dissipating filler according to any one of (1) to (5) above, wherein the aspect ratio of the fibrous aluminum nitride is 2 or more and 200 or less.

[0016] (7) A resin composition used for producing a resin molded body made of a material containing a resin material, the resin composition comprising the heat dissipating filler according to any one of (1) to (6) above.

[0017] (8) The resin composition according to (7) above, wherein the content of the resin material in the resin composition is 5% by volume or more and 60% by volume or less.

[0018] (9) A resin molded body made of a material containing a resin material, characterized in that it contains the heat dissipating filler according to any one of (1) to (6) above.

[0019] (10) The resin molded product according to (9) above, wherein the content of the resin material in the resin molded product is 5% by volume or more and 60% by volume or less.

[0020] (11) The resin molded article according to (9) or (10) above, wherein the thermal conductivity in each of three mutually perpendicular axial directions is 0.5 W / m·K or more and 20 W / m·K or less.

[0021] (12) The resin molding according to any one of (9) to (11) above, having a withstand voltage of 1 kV / mm or more and 100 kV / mm or less.

[0022] According to the present invention, it is possible to provide a heat-dissipating filler that can reduce overall thermal resistance and can be suitably used for producing resin molded bodies that have excellent thermal conductivity not only in the in-plane direction but also in the thickness direction; to provide a resin composition that can be suitably used for producing resin molded bodies that can reduce overall thermal resistance and have excellent thermal conductivity not only in the in-plane direction but also in the thickness direction; and to provide a resin molded body that can reduce overall thermal resistance and has excellent thermal conductivity not only in the in-plane direction but also in the thickness direction.

[0023] Fig. 1 is a schematic diagram showing an example of a configuration of a heat dissipating filler and a resin molded body, and Fig. 2 is a schematic diagram showing an example of a usage form of the resin molded body shown in Fig. 1.

[0024] Preferred embodiments of the present invention will be described in detail below. [1] Thermally conductive filler First, the thermally conductive filler of the present invention will be described.

[0025] FIG. 1 is a schematic diagram showing an example of the configuration of the heat-dissipating filler and resin molded article of the present invention.

[0026] The heat dissipating filler 10 of the present invention is a heat dissipating filler used in the production of a resin molded body 1, and contains first heat conductive particles 12 having a particle size of 10 μm or more and 150 μm or less, second heat conductive particles 13 having a particle size of 0.1 μm or more and less than 10 μm, and fibrous aluminum nitride 11.

[0027] The heat dissipating filler 10 of the present invention is characterized in that, when the total amount of the first heat conductive particles 12, the second heat conductive particles 13, and the fibrous aluminum nitride 11 is 100 parts by volume, it contains the first heat conductive particles 12 in a proportion of 30 parts by volume or more and 80 parts by volume or less, the second heat conductive particles 13 in a proportion of 5 parts by volume or more and 50 parts by volume or less, and the fibrous aluminum nitride 11 in a proportion of 1 part by volume or more and 40 parts by volume or less.

[0028] Since the heat dissipating filler 10 of the present invention contains fibrous aluminum nitride 11, a large number of heat transfer paths are suitably formed by the plurality of fibrous aluminum nitride 11.

[0029] Furthermore, the thermally conductive filler 10 of the present invention contains first thermally conductive particles 12 with a relatively large particle size and second thermally conductive particles 13 with a relatively small particle size in a predetermined ratio, which allows the first thermally conductive particles 12 to enter the gaps between the relatively large fibrous aluminum nitride 11, and further allows the second thermally conductive particles 13 to enter the gaps between the fibrous aluminum nitride 11 and the first thermally conductive particles 12. This allows the fibrous aluminum nitride 11 and the first thermally conductive particles 12 and second thermally conductive particles 13 to be densely packed together, which favorably forms a greater number of heat transfer paths and improves thermal conductivity.

[0030] In particular, by including a predetermined proportion of first thermally conductive particles 12 and second thermally conductive particles 13 in addition to fibrous aluminum nitride 11, the overall thermal resistance can be reduced, and, for example, a heat transfer path can be preferably formed not only in the in-plane direction of the resin molded body 1 but also in the thickness direction.

[0031] In this specification, the particle size of the thermally conductive particles (first thermally conductive particles 12 and second thermally conductive particles 13) can be determined by image analysis of enlarged images taken with a scanning electron microscope (SEM).

[0032] In the present invention, the thermally conductive particles refer to particles made of a material having a thermal conductivity of 1 W / (m·K) or more at 25° C. by itself.

[0033] Furthermore, by including the first thermally conductive particles 12 and the second thermally conductive particles 13 in a predetermined ratio, the fibrous aluminum nitride 11 can exist in a state with minimal bending during the molding process of the resin molded body 1, making it easier to ensure a heat transfer path.

[0034] On the other hand, if the above conditions are not met, satisfactory results cannot be obtained. For example, even if the thermally conductive filler 10 contains the first thermally conductive particles 12 and the second thermally conductive particles 13, if it does not contain the fibrous aluminum nitride 11, the heat transfer paths, particularly the in-plane heat transfer paths, of the resin molded body 1 manufactured using the thermally conductive filler 10 cannot be suitably formed, and the thermal resistance of the resin molded body 1 manufactured using the thermally conductive filler 10 as a whole cannot be sufficiently reduced.

[0035] Furthermore, even if the heat-dissipating filler 10 contains fibrous aluminum nitride 11, if it does not contain both the first heat-conducting particles 12 and the second heat-conducting particles 13, it will not be possible to achieve the filling structure described above, and the heat transfer paths, particularly the heat transfer paths in the thickness direction, of the resin molded body 1 manufactured using the heat-dissipating filler 10 will not be formed properly, and the thermal resistance of the entire resin molded body 1 manufactured using the heat-dissipating filler 10 will not be sufficiently reduced.

[0036] Furthermore, even if the resin molding 1 contains fibrous aluminum nitride 11 and second thermally conductive particles 13, if it does not contain first thermally conductive particles 12, or even if it contains fibrous aluminum nitride 11 and first thermally conductive particles 12, if it contains thermally conductive particles with smaller particle diameters instead of the second thermally conductive particles 13, the heat transfer path of the resin molding 1 manufactured using the heat dissipating filler 10 cannot be formed properly, and the overall thermal resistance becomes high.

[0037] Furthermore, even if the resin molded body 1 contains fibrous aluminum nitride 11 and first thermally conductive particles 12, if it does not contain second thermally conductive particles 13, or if it contains fibrous aluminum nitride 11 and second thermally conductive particles 13 but contains thermally conductive particles with larger particle diameters instead of the first thermally conductive particles 12, the filling structure described above cannot be obtained, and the heat transfer path of the resin molded body 1 manufactured using the heat dissipating filler 10 cannot be suitably formed.

[0038] Furthermore, if the content of the first thermally conductive particles 12 is less than the above-mentioned lower limit, the above-mentioned densely packed structure cannot be achieved, and the heat transfer paths of the resin molded body 1 manufactured using the heat dissipating filler 10 are not sufficiently formed. Furthermore, the hardness of the resin molded body 1 increases, resulting in an increase in the overall thermal resistance.

[0039] Furthermore, if the content of the first thermally conductive particles 12 exceeds the upper limit, the overall thermal resistance of the resin molded body 1 produced using the heat dissipating filler 10 becomes high.

[0040] Furthermore, if the content of the second thermally conductive particles 13 is less than the above-mentioned lower limit, the above-mentioned densely packed structure cannot be achieved, and the heat transfer paths of the resin molded body 1 manufactured using the heat dissipating filler 10 are not sufficiently formed. Furthermore, the hardness of the resin molded body 1 increases, resulting in an increase in the overall thermal resistance.

[0041] Furthermore, if the content of the second thermally conductive particles 13 exceeds the upper limit, the overall thermal resistance of the resin molded body 1 produced using the heat dissipating filler 10 becomes high.

[0042] Furthermore, if the content of fibrous aluminum nitride 11 is less than the above-mentioned lower limit, the heat transfer path of the resin molded body 1 manufactured using the heat dissipation filler 10, particularly the heat transfer path in the in-plane direction, cannot be made sufficient.

[0043] Furthermore, if the content of fibrous aluminum nitride 11 exceeds the upper limit, the resin molded body 1 manufactured using the heat dissipating filler 10 will have high hardness and thermal resistance, and the weight of the resin molded body 1 will increase, and the moldability of the resin molded body 1 will decrease.

[0044] [1-1] First Thermally Conductive Particles The first thermally conductive particles will now be described.

[0045] The first thermally conductive particles 12 are made of a material having thermal conductivity and have a particle size of 10 μm or more and 150 μm or less.

[0046] Examples of materials constituting the first thermally conductive particles 12 include metal oxides such as aluminum oxide (alumina), zinc oxide, magnesium oxide, titanium oxide, silicon oxide, silicon dioxide (silica), and beryllium oxide; metal hydroxides such as aluminum hydroxide and magnesium hydroxide; nitrides such as aluminum nitride, silicon nitride, and boron nitride; carbides such as boron carbide, titanium carbide, and silicon carbide; carbon-based materials such as graphite and black lead; and metals such as aluminum, copper, nickel, and silver. One or more selected from these may be used in combination.

[0047] If electrical insulation is required for the heat dissipating filler 10 or the resin molded body 1, it is preferable that it be at least one selected from the group consisting of metal oxides, metal hydroxides and nitrides, and it may be an amphoteric hydroxide or amphoteric oxide, and specific examples include aluminum hydroxide, boron nitride, aluminum nitride, zinc oxide, aluminum oxide (alumina), silicon dioxide (silica), magnesium oxide, magnesium hydroxide, etc., and one or more selected from these may be used in combination.

[0048] Among these, it is preferable that the material constituting the first thermally conductive particles 12 contains at least one selected from the group consisting of aluminum nitride, boron nitride, and alumina.

[0049] This allows the thermal conductivity of the heat-dissipating filler 10 and the resin molded body 1 produced using the heat-dissipating filler 10 to be improved.

[0050] Furthermore, since these materials have excellent thermal conductivity and high electrical insulation, the resin molded body 1 produced can be suitably used, for example, as a heat dissipation component for electronic devices and the like that require higher insulation properties.

[0051] In particular, alumina is chemically stable, readily available, and relatively inexpensive, allowing for a stable supply and contributing to reduced manufacturing costs. In addition, the strength of the resin molded body 1 can be increased.

[0052] Furthermore, by using aluminum nitride, the thermal conductivity of the aluminum nitride itself is high, and the thermal resistance between the aluminum nitride and the fibrous aluminum nitride 11 can be more effectively reduced. Therefore, the thermal conductivity of the heat dissipating filler 10 and the resin molded body 1 produced using the heat dissipating filler 10 can be made particularly high.

[0053] Furthermore, the use of boron nitride can improve heat dissipation, and boron nitride has high chemical stability and excellent environmental resistance.

[0054] The particle size of the first thermally conductive particles 12 may be from 10 μm to 150 μm, but the average particle size of the first thermally conductive particles 12 is preferably from 15 μm to 140 μm, more preferably from 20 μm to 130 μm, and even more preferably from 25 μm to 120 μm, which makes the above-mentioned effects of the present invention more pronounced.

[0055] In this specification, unless otherwise specified, the average particle size means the particle size at which the frequency of particles reaches 50% when the particle amount is cumulatively calculated from the small particle size side in the particle distribution measured by image analysis, and can be determined, for example, by measurement using a particle shape image analyzer "PITA-04" (manufactured by Seishin Enterprise Co., Ltd.).

[0056] In the thermally conductive filler 10, when the total amount of the first thermally conductive particles 12, the second thermally conductive particles 13, and the fibrous aluminum nitride 11 is taken as 100 parts by volume, the first thermally conductive particles 12 are preferably contained in an amount of 35 parts by volume or more and 75 parts by volume or less, and more preferably 40 parts by volume or more and 70 parts by volume or less, thereby making the above-mentioned effects of the present invention more pronounced.

[0057] [1-2] Second Thermally Conductive Particles The second thermally conductive particles will now be described.

[0058] The second thermally conductive particles 13 are made of a material having thermal conductivity and have a particle size of 0.1 μm or more and less than 10 μm.

[0059] The materials constituting the second thermally conductive particles 13 may be the same as those constituting the first thermally conductive particles 12 described above, but it is preferable that the second thermally conductive particles 13 contain at least one selected from the group consisting of aluminum nitride, alumina, and silica.

[0060] This allows the thermal conductivity of the heat-dissipating filler 10 and the resin molded body 1 produced using the heat-dissipating filler 10 to be improved.

[0061] These materials have excellent thermal conductivity and high electrical insulation, and therefore the resin molded body 1 produced can be used as a heat dissipation member for electronic devices and the like that require high insulation.

[0062] In particular, silica has thermal expansion properties similar to those of a silicon-based semiconductor substrate, and therefore the resin molded body 1 can be more suitably used as a heat dissipation member for, for example, an electronic device.

[0063] The particle size of the second thermally conductive particles 13 may be 0.1 μm or more and less than 10 μm, but the average particle size of the second thermally conductive particles 13 is preferably 0.2 μm or more and 9.5 μm or less, more preferably 0.3 μm or more and 9.0 μm or less, and even more preferably 0.4 μm or more and 8.0 μm or less, which makes the above-mentioned effects of the present invention more pronounced.

[0064] In the thermally conductive filler 10, when the total amount of the first thermally conductive particles 12, the second thermally conductive particles 13, and the fibrous aluminum nitride 11 is taken as 100 parts by volume, the second thermally conductive particles 13 are preferably contained in an amount of 10 parts by volume or more and 45 parts by volume or less, and more preferably 15 parts by volume or more and 40 parts by volume or less, thereby making the above-mentioned effects of the present invention more pronounced.

[0065] [1-3] Fibrous Aluminum Nitride Fibrous aluminum nitride will now be described.

[0066] Aluminum nitride is a material that has high thermal conductivity and high insulating properties. The fibrous aluminum nitride 11 is a component that plays an important role in improving the thermal conductivity of the resin molded body 1 by forming a heat dissipation path that increases the contact efficiency between fillers. It is also an important component in improving the flexibility, transparency, moldability, etc. of the resin molded body 1.

[0067] The fibrous aluminum nitride 11 may be polycrystalline, but is preferably composed of single crystal whiskers.

[0068] Since single crystal whiskers have a higher thermal conductivity than polycrystals, the thermal conductivity of the heat dissipating filler 10 and the resin molded body 1 produced using the heat dissipating filler 10 can be made higher.

[0069] Furthermore, by using high-purity single crystal whiskers as the fibrous aluminum nitride 11, the thermal conductivity can be increased compared to polycrystalline materials containing a large amount of impurities, and the volume fraction of the fibrous aluminum nitride 11 can be reduced.

[0070] This makes it possible to maintain the mechanical properties of the resin molded body 1, such as flexibility, particularly when the resin molded body 1 is in a sheet form.

[0071] Furthermore, the single crystal whiskers used as the fibrous aluminum nitride 11 preferably have a hexagonal wurtzite crystal structure with the (0002) plane positioned perpendicular to the c-axis direction. Such single crystal whiskers can achieve a thermal conductivity of 120 W / m K or more and 320 W / m K or less.

[0072] In this embodiment, the single crystal whiskers (AlN whiskers) serving as the fibrous aluminum nitride 11 may include a single crystal body of fibrous aluminum nitride 11 and an oxygen-containing layer cylindrically covering the surface of the single crystal body of aluminum nitride 11. Each of the fibrous aluminum nitride 11 may further include a hydrophobic layer cylindrically covering the oxygen-containing layer outside the oxygen-containing layer.

[0073] Details of the structure and manufacturing method of such fibrous aluminum nitride 11 are publicly known, for example, from Japanese Patent Application Laid-Open No. 2014-73951 and Japanese Patent Application Laid-Open No. 2018-154534, and therefore detailed description thereof will be omitted.

[0074] The length in the major axis direction of the fibrous aluminum nitride 11 is preferably 1.0 μm or more and 5.0 cm or less, more preferably 5.0 μm or more and 4.0 cm or less, and even more preferably 10.0 μm or more and 3.0 cm or less.

[0075] This increases the number of contact points between the fibrous aluminum nitride 11. Therefore, many heat transfer paths can be secured by contact between the fibrous aluminum nitride 11, and the thermal conductivity of the resin molded body 1 produced using the heat dissipation filler 10 can be increased.

[0076] The length in the minor axis direction of the fibrous aluminum nitride 11 is preferably 0.5 μm or more and 50.0 μm or less, more preferably 1.0 μm or more and 40.0 μm or less, and even more preferably 5.0 μm or more and 30.0 μm or less.

[0077] This allows a large number of heat transfer paths to be preferably formed by the multiple fibrous aluminum nitrides 11, thereby improving the thermal conductivity of the heat dissipating filler 10 and the resin molded body 1 manufactured using the heat dissipating filler 10.

[0078] The lengths of the fibrous aluminum nitride 11 in the major axis direction and the minor axis direction can be measured by image analysis of an enlarged image taken with a scanning electron microscope (SEM).

[0079] The aspect ratio of the fibrous aluminum nitride 11 (the value obtained by dividing the length in the major axis direction by the length in the minor axis direction) is preferably 2 or more and 200 or less, more preferably 3 or more and 180 or less, and even more preferably 5 or more and 150 or less.

[0080] This makes it possible to more efficiently increase the contact density per unit volume between the fibrous aluminum nitride 11, and even if the content is relatively small, it is possible to impart high thermal conductivity to the resin molded body 1. Furthermore, for example, when the resin molded body 1 is in a sheet shape, it is possible to make the mechanical properties of the resin molded body 1, such as flexibility, more suitable.

[0081] If the aspect ratio exceeds the upper limit, the fibrous aluminum nitride 11 is more likely to be broken or otherwise damaged during the production of the resin molded body 1, which may result in an increase in fine powder.

[0082] In the thermally conductive filler 10, when the total amount of the first thermally conductive particles 12, the second thermally conductive particles 13, and the fibrous aluminum nitride 11 is taken as 100 parts by volume, the fibrous aluminum nitride 11 is preferably contained in an amount of 5 parts by volume or more and 35 parts by volume or less, and more preferably 10 parts by volume or more and 30 parts by volume or less, thereby making the above-mentioned effects of the present invention more pronounced.

[0083] [1-4] Other Components The thermally conductive filler 10 may contain components other than the above-mentioned fibrous aluminum nitride 11, first thermally conductive particles 12, and second thermally conductive particles 13. Hereinafter, in this section, such components will be referred to as "other components."

[0084] Examples of other components include heat conductive particles with a particle size of less than 0.1 μm, heat conductive particles with a particle size of more than 10 μm, and heat conductive fibers made of materials other than aluminum nitride.

[0085] However, the content of other components in the heat-dissipating filler 10 is preferably 5% by volume or less, more preferably 3% by volume or less, and even more preferably 1% by volume or less.

[0086] [2] Resin Composition Next, the resin composition of the present invention will be described.

[0087] The resin composition of the present invention is a resin composition used to manufacture a resin molded body 1 made of a material containing a resin material 20, and is characterized by including the heat dissipating filler 10 described above.

[0088] As a result, the resin molded body 1 manufactured using the resin composition has a large number of heat transfer paths preferably formed by the heat dissipation filler 10, reducing the overall thermal resistance and providing excellent thermal conductivity not only in the in-plane direction but also in the thickness direction.

[0089] [2-1] Heat-dissipating filler The resin composition of the present invention contains the heat-dissipating filler 10 described above.

[0090] The content of the heat dissipating filler 10 in the resin composition is preferably 5% by volume or more and 60% by volume or less, more preferably 10% by volume or more and 55% by volume or less, and even more preferably 15% by volume or more and 50% by volume or less.

[0091] This makes it possible to more effectively achieve both the effect of improving the thermal conductivity of the resin molded body 1 produced using the resin composition, thereby reducing the overall thermal resistance, and the effect of improving the moldability and processability of the resin molded body 1.

[0092] [2-2] Resin Material The resin composition of the present invention contains a resin material 20 .

[0093] The resin material 20 may be, for example, a thermosetting resin such as silicone resin, epoxy resin, phenol resin, melamine resin, urea resin, thermosetting polyimide, unsaturated polyester resin, or polyurethane.

[0094] Furthermore, as the resin material 20, for example, a thermoplastic resin such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, acrylonitrile styrene copolymer, acrylonitrile butadiene styrene copolymer, acrylonitrile ethylene propylene diene styrene copolymer, methacrylic resin, etc. can be used.

[0095] The resin material 20 may be, for example, a fluororesin such as polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride, or polyvinyl fluoride.

[0096] Furthermore, examples of the resin material 20 that can be used include polycarbonate, polyamide resin, polyacetal, polyethylene terephthalate, polybutylene terephthalate, polyether ether ketone, polyphenyl sulfide, polysulfone, polyetherimide, polyamideimide, thermoplastic polyimide, and liquid crystal polymer.

[0097] Furthermore, examples of the resin material 20 that can be used include acrylonitrile styrene acrylate, atactic polypropylene, cellulose acetate, cellulose acetate butyrate, chlorinated vinyl chloride, chloroprene rubber, diallyl phthalate, ethylene ethyl acrylate, ethylene propylene diene terpolymer, ethylene tetrafluoroethylene copolymer, ethylene vinyl acetate copolymer, ethyl vinyl ether, ethylene vinyl alcohol copolymer, perfluoro rubber, tetrafluoroethylene-hexafluoropropylene copolymer, and soft urethane foam.

[0098] Furthermore, examples of the resin material 20 that can be used include glass fiber reinforced plastic, glass fiber reinforced thermoplastic plastic, butyl rubber, ionomer, isoprene rubber, melamine formaldehyde, methyl methacrylate, nitrile rubber, natural rubber, polyacrylic acid, polyaryl ether ketone, polyester alkyd resin, polyacrylonitrile, and polyarylate.

[0099] Furthermore, examples of the resin material 20 that can be used include polyparaphenylene benzobisoxazole, polybutadiene styrene, diallyl terephthalate, polydicyclopentadiene, polyethylene naphthalate, polyethylene oxide, polyethersulfone, phenol formaldehyde, tetrafluoroethylene perfluoroalkyl vinyl ether copolymer, polyisobutylene, and polymethylpentene.

[0100] Furthermore, examples of the resin material 20 that can be used include polyphthalamide, polyphenylene ether, polyphenylene oxide, polytrimethylene terephthalate, reactive polyurethane, polyvinyl alcohol, polyvinyl butyral, acrylic-modified polyvinyl chloride, polyvinyl dichloride, and vinyl chloride-vinyl acetate copolymer.

[0101] Furthermore, examples of the resin material 20 that can be used include polyvinyl formal, polyvinylpyrrolidone, styrene butadiene, styrene butadiene rubber styrene block copolymer, styrene butadiene styrene block copolymer, styrene ethylene butylene styrene block copolymer, styrene ethylene propylene styrene block copolymer, styrene isoprene styrene block copolymer, sheet molding compound, syndiotactic polystyrene, thermoplastic elastomer, thermoplastic polyurethane, urea formaldehyde resin, ultra-high molecular weight polyethylene, vinyl chloride ethylene, vinyl chloride octyl acrylate, cross-linked polyethylene, and the like.

[0102] As the resin material 20, for example, one or a combination of two or more of the above-exemplified materials can be used.

[0103] The content of the resin material 20 in the resin composition is preferably 5% by volume or more and 60% by volume or less, more preferably 10% by volume or more and 55% by volume or less, and even more preferably 15% by volume or more and 50% by volume or less.

[0104] This makes it possible to more suitably achieve both the effect of improving the thermal conductivity of the resin molded body 1 and reducing the overall thermal resistance, and the effect of making the moldability of the resin molded body 1 favorable.

[0105] [2-3] Other Components The resin composition of the present invention may contain components other than the above-described heat-dissipating filler 10 and resin material 20. Hereinafter, in this section, such components will be referred to as "other components."

[0106] Examples of other components include plasticizers, colorants, antioxidants, ultraviolet absorbers, light stabilizers, softeners, modifiers, rust inhibitors, fillers other than the heat-dissipating filler of the present invention described above, bulking agents, electromagnetic wave absorbing materials, surface lubricants, corrosion inhibitors, heat stabilizers, lubricants, primers, antistatic agents, polymerization inhibitors, crosslinking agents, catalysts, leveling agents, thickeners, dispersants, antioxidants, flame retardants, hydrolysis inhibitors, and corrosion inhibitors.

[0107] However, the content of other components in the resin composition of the present invention is preferably 10% by volume or less, more preferably 7% by volume or less, and even more preferably 5% by volume or less.

[0108] [3] Resin Molded Article Next, the resin molded article of the present invention will be described.

[0109] The resin molded body 1 of the present invention is a resin molded body 1 made of a material containing a resin material 20, and is characterized by including the heat dissipating filler 10 described above.

[0110] As a result, the resin molding 1 has a large number of heat transfer paths preferably formed by the heat dissipation filler 10 described above, which reduces the overall thermal resistance and provides excellent thermal conductivity not only in the in-plane direction but also in the thickness direction.

[0111] The resin molded body 1 can be suitably produced, for example, using the resin composition of the present invention described above. Furthermore, in producing the resin molded body 1, a combination of multiple resin compositions of the present invention may be used. Furthermore, the resin molded body 1 may be produced using other components or other compositions in addition to the resin composition of the present invention described above. Examples of such other components or other compositions include a resin material for dilution.

[0112] [3-1] Heat-dissipating filler The resin molded article of the present invention contains the heat-dissipating filler 10 described above.

[0113] The content of the heat dissipating filler 10 in the resin molding 1 is preferably 5% by volume or more and 60% by volume or less, more preferably 10% by volume or more and 55% by volume or less, and even more preferably 15% by volume or more and 50% by volume or less.

[0114] This makes it possible to more suitably achieve both the effect of improving the thermal conductivity of the resin molded body 1 and reducing the overall thermal resistance, and the effect of making the moldability of the resin molded body 1 favorable.

[0115] [3-2] Resin Material The resin molded body of the present invention contains the resin material 20 described above.

[0116] Furthermore, the content of resin material 20 in resin molded body 1 is preferably 5% by volume or more and 60% by volume or less, more preferably 10% by volume or more and 55% by volume or less, and even more preferably 15% by volume or more and 50% by volume or less.

[0117] This makes it possible to more suitably achieve both the effect of improving the thermal conductivity of the resin molded body 1 and reducing the overall thermal resistance, and the effect of making the moldability of the resin molded body 1 favorable.

[0118] [3-3] Other Components The resin molded body 1 may contain components other than the above-described heat-dissipating filler 10 and resin material 20. Hereinafter, in this section, such components will be referred to as "other components."

[0119] Examples of other components include plasticizers, colorants, antioxidants, ultraviolet absorbers, light stabilizers, softeners, modifiers, rust inhibitors, fillers other than the heat-dissipating filler of the present invention described above, bulking agents, electromagnetic wave absorbing materials, surface lubricants, corrosion inhibitors, heat stabilizers, lubricants, primers, antistatic agents, polymerization inhibitors, crosslinking agents, catalysts, leveling agents, thickeners, dispersants, antioxidants, flame retardants, hydrolysis inhibitors, and corrosion inhibitors.

[0120] However, the content of other components in the resin molded article of the present invention is preferably 10% by volume or less, more preferably 7% by volume or less, and even more preferably 5% by volume or less.

[0121] [3-4] Other Conditions The shape of the resin molded body 1 is not particularly limited, and can be, for example, a sheet, a block, or the like, depending on the intended use of the resin molded body 1.

[0122] For example, when the resin molding 1 is in the form of a sheet, the thickness of the resin molding 1 is preferably 0.15 mm or more and 20 mm or less, more preferably 0.20 mm or more and 10 mm or less, and even more preferably 0.25 mm or more and 5 mm or less.

[0123] This allows the sheet-shaped resin molding 1 to suitably conform to the surface shape of the member to which it is applied, and the resin molding 1 can have excellent substantial thermal conductivity.

[0124] Furthermore, if the resin molded body 1 is block-shaped, even if the member to which the resin molded body 1 is applied has a complex surface shape, the resin molded body 1 and the member can be suitably adhered to each other, and the actual thermal conductivity can be excellent.

[0125] The resin molded body 1 preferably satisfies the following conditions: For example, the thermal conductivity of the resin molded body 1 in each of three mutually perpendicular axial directions is preferably 0.5 W / m·K or more and 20 W / m·K or less, more preferably 1.0 W / m·K or more and 19 W / m·K or less, and even more preferably 2.0 W / m·K or more and 18 W / m·K or less.

[0126] This allows the resin molded body 1 to have excellent thermal conductivity in three axial directions that are perpendicular to one another.

[0127] For example, if the three mutually perpendicular axes are the x-axis, y-axis, and z-axis, the x-axis and y-axis are within the plane of the resin molded body 1, and the z-axis is the thickness direction of the resin molded body 1, the resin molded body 1 will have excellent thermal conductivity not only in the in-plane direction but also in the thickness direction.

[0128] The thermal conductivity value can be measured by the hot disk method (compliant with ISO 22007-2) using a TPS-2500S manufactured by Kyoto Electronics Manufacturing Co., Ltd.

[0129] Furthermore, the withstand voltage of the resin molded body 1 is preferably 1 kV / mm or more and 100 kV / mm or less.

[0130] As a result, for example, when the resin molded body 1 is mounted on an electronic component as a sheet-like heat dissipation member, dielectric breakdown can be more effectively suppressed even under high voltage. Therefore, not only can heat from high-heat components be efficiently conducted, but insulation can also be ensured, making the resin molded body 1 more suitable for use as a heat dissipation member for various electronic devices.

[0131] The withstand voltage may be a value measured by a method conforming to JIS C2110-1:2016.

[0132] [4] Method for Producing Resin Molded Article Next, an example of a method for producing a resin molded article will be described.

[0133] First, a plurality (a large number) of fibrous aluminum nitride particles 11 manufactured by a known method, a plurality of first thermally conductive particles 12 manufactured by a known method, and a plurality of second thermally conductive particles 13 manufactured by a known method are prepared in advance, and then mixed in the above-mentioned ratio to obtain the heat dissipation filler 10.

[0134] Next, the obtained heat-dissipating filler 10 and the resin material 20 are mixed and kneaded to obtain a resin composition in which the heat-dissipating filler 10 is uniformly dispersed.

[0135] The resin composition thus obtained is molded into a predetermined shape, and the resin material 20 is solidified (cured), thereby producing the resin molded body 1 .

[0136] [5] Usage of Resin Molded Article Next, usage of the resin molded article will be described. Figure 2 is a diagram schematically showing an example of usage of the resin molded article shown in Figure 1.

[0137] As described above, the resin molded body 1 has a reduced overall thermal resistance and excellent thermal conductivity not only in the in-plane direction but also in the thickness direction. Therefore, the resin molded body 1 can be used as a thermal conductor, for example, as a heat transfer member that comes into contact with various heat dissipation members, a high-temperature member and a heat dissipation member to transfer heat from the high-temperature member to the heat dissipation member and efficiently dissipate the heat from the heat dissipation member, or as a heat transfer member that comes into contact with a heating object to be heated and a high-temperature member that is at a higher temperature than the heating object to transfer thermal energy from the high-temperature member to the heating object and efficiently heat the heating object.

[0138] In the following description, the resin molded article will be mainly described as being used as a thermal conductor, but the use of the resin molded article of the present invention is not limited to this example.

[0139] As described above, the shape of the resin molded body 1 is not particularly limited, and can be, for example, a sheet or a block depending on the application of the resin molded body 1 .

[0140] The following description will be focused on the case where the resin molded body 1 is used in contact with at least a part of the surface of a high-temperature member that is a heat generating body.

[0141] The high-temperature component is not particularly limited as long as it reaches a temperature higher than the ambient atmosphere, and examples thereof include various electronic components and electrical components. More specifically, examples include computer central processing units (CPUs), image processing processors (GPUs), power devices, FPGAs, ASICs, smartphone SoCs, DSPs and microcontrollers in embedded devices, semiconductor elements such as transistors, light-emitting diodes (LEDs), electroluminescent devices, liquid crystals, and other light emitters, imaging elements such as CCDs and image sensors (e.g., 8K), switching regulators, motor coils, printer heads, etc. Furthermore, the high-temperature component may be, for example, a relay, a battery, a transformer, a power supply unit, a bearing, an electron gun, a vacuum tube, a high-frequency oscillator, etc. Furthermore, the high-temperature component may be, for example, a tube or a container containing a high-temperature fluid.

[0142] The maximum surface temperature of the high-temperature member is preferably 30°C or higher and 180°C or lower, more preferably 40°C or higher and 140°C or lower, and even more preferably 50°C or higher and 100°C or lower.

[0143] As described above, the resin molded body 1 reduces the overall thermal resistance and has excellent thermal conductivity not only in the in-plane direction but also in the thickness direction, so that the substantial thermal conductivity from the high-temperature component to the heat-dissipating component can be excellent, thereby enabling the high-temperature component to be cooled efficiently.

[0144] In the example shown in FIG. 2, a sheet-shaped resin molded body 1 is disposed between a high temperature member 100, which is a heat generating body, and a heat dissipation member 110, and is thermally coupled thereto.

[0145] The resin molded body 1 may be in contact with a heat dissipation member. In other words, the resin molded body 1 may be used not as a heat dissipation member but as a heat transfer member that contacts a high-temperature member and a heat dissipation member, transfers heat from the high-temperature member to the heat dissipation member, and efficiently dissipates heat from the heat dissipation member. This can improve the efficiency of heat dissipation from the high-temperature member.

[0146] The resin molded article of the present invention can be applied to electronic devices. Such electronic devices have, for example, electronic components and the resin molded article of the present invention as a heat dissipation member or the heat transfer member described above.

[0147] Examples of electronic devices to which the resin molded article of the present invention can be applied include small electronic devices.

[0148] Examples of small electronic devices include notebook computers, tablet devices, portable communication terminal devices, mobile phones, smartphones, portable music players, portable radios, portable televisions, digital cameras, video cameras, portable game devices, e-book readers, and portable medical devices.

[0149] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above.

[0150] For example, in the above explanation, an example was given in which the resin molded body is rectangular in plan view, but the shape of the resin molded body can be appropriately set depending on the shape of the component that comes into contact with the resin molded body, etc.

[0151] In addition, for example, in the above-described embodiment, the resin molded body is typically in the form of a sheet or block having a relatively flat surface, but the resin molded body may also be in the form of a sheet having a stepped surface. Such a resin molded body can be suitably used as a TIM sheet for cooling components having complex surface shapes, such as CCDs, LEDs, and small sensor modules.

[0152] Furthermore, the resin molded body of the present invention is not limited to those produced by the above-mentioned methods. More specifically, for example, the resin molded body of the present invention is not limited to those produced using the heat dissipating filler of the present invention or the resin composition of the present invention. For example, the resin molded body of the present invention may be produced using a first resin composition containing first thermally conductive particles and a resin material but not containing second thermally conductive particles and fibrous aluminum nitride, a second resin composition containing second thermally conductive particles and a resin material but not containing the first thermally conductive particles and fibrous aluminum nitride, and a third resin composition containing fibrous aluminum nitride and a resin material but not containing the first thermally conductive particles and the second thermally conductive particles.

[0153] The present invention will be described in more detail below with reference to specific examples, but the present invention is not limited to these examples. In the following description, treatments for which no temperature conditions are specified were performed at room temperature, specifically 25°C. Furthermore, various measurement conditions for which no temperature conditions are specified are values ​​at room temperature, specifically 25°C.

[0154] [6] Production of heat-dissipating filler (Example 1)

[0155] A powder (manufactured by Toyo Aluminum Co., Ltd.) was prepared as an aggregate of particles made of aluminum nitride. This powder was classified to obtain a powder (first powder) as an aggregate of particles made of first thermally conductive particles having a particle size of 10 μm to 150 μm. The first thermally conductive particles had an average particle size of 20 μm.

[0156] A powder (manufactured by Tokuyama Corporation) was prepared as an aggregate of particles made of aluminum nitride. This powder was classified to obtain a powder (second powder) as an aggregate of particles made of second thermally conductive particles with a particle size of 0.1 μm or more and less than 10 μm. The average particle size of the second thermally conductive particles was 1 μm.

[0157] Thermalnite manufactured by U-MAP was prepared as fibrous aluminum nitride. The fibrous aluminum nitride had a length in the major axis direction of 1.0 μm or more and 5.0 cm or less, a length in the minor axis direction of 0.5 μm or more and 50.0 μm or less, and an aspect ratio of 2 or more and 200 or less. The fibrous aluminum nitride had an average length in the major axis direction of 20 μm, an average length in the minor axis direction of 2 μm, and an average aspect ratio of 10.

[0158] The first powder, the second powder, and the fibrous aluminum nitride were mixed in a volume ratio of 65:30:5 to obtain a heat dissipating filler.

[0159] The particle size was measured using a particle shape image analyzer "PITA-04" (manufactured by Seishin Enterprise Co., Ltd.).

[0160] (Examples 2 to 7) Heat dissipating fillers were manufactured in the same manner as in Example 1, except that the mixing ratio of the first powder, the second powder, and the fibrous aluminum nitride was changed so that the volume ratio of the first thermally conductive particles, the second thermally conductive particles, and the fibrous aluminum nitride was as shown in Table 1.

[0161] (Comparative Examples 1 to 6) Heat dissipating fillers were manufactured in the same manner as in Example 1, except that the mixing ratio of the first powder, the second powder, and the fibrous aluminum nitride was changed so that the volume ratio of the first thermally conductive particles, the second thermally conductive particles, and the fibrous aluminum nitride was as shown in Table 1.

[0162] Comparative Example 7 A thermally conductive filler was produced in the same manner as in Example 1, except that the first powder and the second powder were mixed in a volume ratio of 68.4:31.6 without using fibrous aluminum nitride. In other words, the thermally conductive filler of this comparative example does not contain fibrous aluminum nitride.

[0163] The configurations of the heat-dissipating fillers in the examples and comparative examples are summarized in Table 1.

[0164] Table 1

[0165] [7] Evaluation The following evaluations were carried out using the heat-dissipating fillers of the examples and comparative examples.

[0166] [7-1] Evaluation of Thermal Conductivity The heat-dissipating fillers of each of the Examples and Comparative Examples were dispersed in silicone resin to produce resin compositions. The content of the heat-dissipating filler in each resin composition was 50% by volume, and the content of the resin in each resin composition was 50% by volume. The thermal conductivity of the silicone resin at 25°C was 0.2 W / (m K).

[0167] Each of the obtained resin compositions was poured into a disk-shaped silicone mold having a diameter of 45 mm and a thickness of 5 mm, molded, and treated at 100°C for 60 minutes to obtain a resin molded body as a sample for measuring thermal conductivity.

[0168] Each of the obtained thermal conductivity measurement samples was measured by the hot disk method (compliant with ISO 22007-2) using a TPS-2500S manufactured by Kyoto Electronics Manufacturing Co., Ltd., and the thermal conductivity in the in-plane direction and thickness direction was measured. The values ​​were evaluated according to the following criteria.

[0169] A: Thermal conductivity is 5 W / (m.K) or more and 20 W / (m.K) or less. B: Thermal conductivity is 4 W / (m.K) or more and less than 5 W / (m.K). C: Thermal conductivity is 3.5 W / (m.K) or more and less than 4 W / (m.K). D: Thermal conductivity is 2.5 W / (m.K) or more and less than 3.5 W / (m.K). E: Thermal conductivity is less than 2.5 W / (m.K).

[0170] [7-2] Evaluation of Thermal Resistance Each of the obtained resin compositions was cast into a disk-shaped silicone mold having a diameter of 45 mm and a thickness of 0.2 mm.

[0171] For each of the obtained thermal conductivity measurement samples, measurements were carried out in accordance with ASTM D5470 using DynTIM S from Mentor Graphics Corp., and the thermal resistance in the thickness direction was measured and evaluated according to the following criteria.

[0172] A: Thermal resistance is 1.5 (cm ２ B: Thermal resistance is less than 1.5 (cm ２・K) / W or more 1.7 (cm ２ C: Thermal resistance is less than 1.7 (cm ２ ・K) / W or more 2.0(cm ２ D: Thermal resistance is less than 2.0 (cm ２ ・K) / W or more 2.5(cm ２ E: Thermal resistance is less than 2.5 (cm ２ ・K) / W or more.

[0173] These results are summarized in Table 2.

[0174] Table 2

[0175] As is clear from Table 2, excellent effects were obtained in the present invention, whereas satisfactory results were not obtained in the comparative examples.

[0176] In addition, a heat dissipation filler was manufactured in the same manner as in each of the above examples, except that particles made of alumina and particles made of boron nitride were used instead of particles made of aluminum nitride as the first thermally conductive particles, and when evaluated in the same manner as above, good results were obtained as above.

[0177] In addition, a heat dissipation filler was manufactured in the same manner as in each of the above examples, except that particles made of alumina and particles made of silica were used instead of particles made of aluminum nitride as the second heat conduction particles, and when evaluated in the same manner as above, good results were obtained as above.

[0178] In addition, in preparing the resin composition, resin compositions and resin molded articles were produced in the same manner as described above, except that the content of the resin material was variously changed within the range of 5% by volume or more and 60% by volume or less, and evaluated in the same manner as above, and similarly good results were obtained.

[0179] In addition, in the resin molded bodies according to the above-mentioned respective Examples, the thermal conductivity in the three mutually perpendicular axial directions was in the range of 0.5 W / m·K or more and 20 W / m·K or less.

[0180] Furthermore, the endurance voltage values ​​of the resin molded bodies according to each of the examples, measured by a method conforming to JIS C2110-1:2016, were all within the range of 1 kV / mm or more and 100 kV / mm or less.

[0181] The thermally conductive filler of the present invention is a thermally conductive filler used in the production of resin molded articles. The thermally conductive filler contains first thermally conductive particles having a particle size of 10 μm or more and 150 μm or less, second thermally conductive particles having a particle size of 0.1 μm or more and less than 10 μm, and fibrous aluminum nitride. When the total amount of the first thermally conductive particles, the second thermally conductive particles, and the fibrous aluminum nitride is taken as 100 parts by volume, the first thermally conductive particles are contained in a proportion of 30 parts by volume or more and 80 parts by volume or less, the second thermally conductive particles are contained in a proportion of 5 parts by volume or more and 50 parts by volume or less, and the fibrous aluminum nitride is contained in a proportion of 1 part by volume or more and 40 parts by volume or less. Such a thermally conductive filler can reduce overall thermal resistance and is suitable for use in the production of resin molded articles that have excellent thermal conductivity not only in the in-plane direction but also in the thickness direction. Therefore, the thermally conductive filler of the present invention has industrial applicability.

[0182] The resin composition of the present invention is a resin composition used for producing a resin molded article composed of a material containing a resin material, and contains the heat dissipating filler of the present invention. Such a resin composition can reduce overall thermal resistance and can be suitably used for producing a resin molded article that has excellent thermal conductivity not only in the in-plane direction but also in the thickness direction. Therefore, the resin composition of the present invention has industrial applicability.

[0183] The resin molded article of the present invention is a resin molded article made of a material containing a resin material, and includes the heat dissipating filler of the present invention. Such a resin molded article can reduce overall thermal resistance and has excellent thermal conductivity not only in the in-plane direction but also in the thickness direction. Therefore, the resin molded article of the present invention has industrial applicability.

[0184] REFERENCE SIGNS LIST 1 resin molded body 10 heat dissipating filler 11 fibrous aluminum nitride 12 first heat conductive particle 13 second heat conductive particle 20 resin material 100 high temperature member 110 heat dissipating member

Claims

1. A heat dissipating filler used in the production of resin molded bodies, comprising: first heat conductive particles having a particle size of 10 μm or more and 150 μm or less; second heat conductive particles having a particle size of 0.1 μm or more and less than 10 μm; and fibrous aluminum nitride, wherein, when the total amount of the first heat conductive particles, the second heat conductive particles, and the fibrous aluminum nitride is 100 parts by volume, the heat dissipating filler contains the first heat conductive particles in a ratio of 30 parts by volume or more and 80 parts by volume or less, the second heat conductive particles in a ratio of 5 parts by volume or more and 50 parts by volume or less, and the fibrous aluminum nitride in a ratio of 1 part by volume or more and 40 parts by volume or less.

2. The thermally conductive filler according to claim 1, wherein said first thermally conductive particles contain at least one selected from the group consisting of aluminum nitride, boron nitride and alumina.

3. The heat dissipating filler according to claim 1, wherein said second thermally conductive particles contain at least one selected from the group consisting of aluminum nitride, alumina and silica.

4. The heat dissipating filler according to claim 1, wherein the length of the fibrous aluminum nitride in the major axis direction is 1.0 μm or more and 5.0 cm or less.

5. A heat dissipating filler according to claim 1, wherein the length of the fibrous aluminum nitride in the minor axis direction is 0.5 μm or more and 50.0 μm or less.

6. The heat dissipating filler according to claim 1, wherein the aspect ratio of the fibrous aluminum nitride is 2 or more and 200 or less.

7. A resin composition used in the manufacture of a resin molded product made of a material containing a resin material, the resin composition comprising the heat dissipating filler according to any one of claims 1 to 6.

8. The resin composition according to claim 7, wherein the content of the resin material in the resin composition is 5% by volume or more and 60% by volume or less.

9. A resin molded product made of a material containing a resin material, the resin molded product comprising the heat dissipating filler according to any one of claims 1 to 6.

10. The resin molded product according to claim 9, wherein the content of the resin material in the resin molded product is 5 volume % or more and 60 volume % or less.

11. The resin molded article according to claim 9, wherein the thermal conductivity in each of three mutually perpendicular axial directions is 0.5 W / m·K or more and 20 W / m·K or less.

12. The resin molding according to claim 9, which has a withstand voltage of 1 kV / mm or more and 100 kV / mm or less.

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