Heat dissipation filler, resin composition, and resin molded body

Abstract

A heat dissipation filler according to the present invention is for use in producing a resin molded body, is characterized by comprising first thermally conductive particles having a particle size of 50-300 µm, second thermally conductive particles having a particle size of not less than 5 µm to less than 50 µm, third thermally conductive particles having a particle size of not less than 0.1 µm to less than 5 µm, and a fibrous aluminum nitride, and is characterized in that, when the total amount of the first thermally conductive particles, the second thermally conductive particles, the third thermally conductive particles, and the fibrous aluminum nitride is defined as 100.0 parts by volume, the first thermally conductive particles are contained at a proportion of 40.0-70.0 parts by volume, the second thermally conductive particles are contained at a proportion of 7.0-30.0 parts by volume, the third thermally conductive particles are contained at a proportion of 22.0-45.0 parts by volume, and the fibrous aluminum nitride is contained at a proportion of 0.5-13.5 parts by volume.

Description

Heat dissipation filler, resin composition, and resin molded body

[0001] The present invention relates to a heat dissipation filler, a resin composition, and a resin molded body.

[0002] Since aluminum nitride (AlN) is an insulator having high thermal conductivity, it is used as an insulating heat dissipation member for electronic devices and the like. For example, an AlN sintered body obtained by sintering this has a thermal expansion coefficient close to that of silicon (Si), and thus is suitable as a heat dissipation plate or a substrate for a semiconductor device using silicon. On the other hand, the use of a particulate dispersion composite material such as a resin molded body in which AlN particles are dispersed has also been proposed.

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

[0004] For example, as a resin molded body having both thermal conductivity and moldability, a resin molded body containing an anisotropic AlN filler in which AlN single crystal particles are fused and fibrous, together with isotropic particles, has been proposed (see, for example, Patent Document 1).

[0005] Also, a resin composition made of an epoxy resin or a silicone resin containing AlN whiskers with reduced impurity incorporation and suppressed reduction in thermal conductivity has been proposed (see, for example, Patent Document 2).

[0006] In these resin molded bodies, by dispersing AlN whiskers having a high aspect ratio in the resin molded body so as to face random directions in the length direction, the contact density between the AlN whiskers can be increased, and high thermal conductivity can be imparted to the resin molded body.

[0007] However, it has been difficult to make the overall thermal conductivity sufficiently excellent. Further, for example, when the resin molded body is in the form of a sheet, even if the in-plane thermal conductivity is excellent, it has not been possible to make the thickness-direction thermal conductivity sufficiently excellent.

[0008] Japanese Patent Publication No. 2010-235842 Japanese Patent Publication No. 2016-145120

[0009] The object of the present invention is to provide a heat dissipation filler that can be suitably used in the manufacture of a resin molded article having excellent overall thermal conductivity, for example, 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 in the manufacture of a resin molded article having excellent overall thermal conductivity, for example, excellent thermal conductivity not only in the in-plane direction but also in the thickness direction; and to provide a resin molded article having excellent overall thermal conductivity, for example, excellent thermal conductivity not only in the in-plane direction but also in the thickness direction.

[0010] These objectives are achieved by the present invention as described in (1) to (17) below. (1) A heat dissipation filler used in the manufacture of a resin molded article, comprising: first heat conductive particles having a particle size of 50 μm or more and 300 μm or less; second heat conductive particles having a particle size of 5 μm or more and less than 50 μm; third heat conductive particles having a particle size of 0.1 μm or more and less than 5 μm; and fibrous aluminum nitride, wherein when the total amount of the first heat conductive particles, the second heat conductive particles, the third heat conductive particles, and the fibrous aluminum nitride is 100.0 parts by volume, the first heat conductive particles are contained in a proportion of 40.0 parts by volume or more and 70.0 parts by volume or less; the second heat conductive particles are contained in a proportion of 7.0 parts by volume or more and 30.0 parts by volume or less; the third heat conductive particles are contained in a proportion of 22.0 parts by volume or more and 45.0 parts by volume or less; and the fibrous aluminum nitride is contained in a proportion of 0.5 parts by volume or more and 13.5 parts by volume or less.

[0011] (2) The heat dissipation filler according to (1) above, wherein the first heat conducting particle comprises at least one selected from the group consisting of aluminum nitride and boron nitride.

[0012] (3) The heat dissipation filler according to (1) or (2) above, wherein the second heat conducting particle comprises at least one selected from the group consisting of aluminum nitride and boron nitride.

[0013] (4) The heat dissipation filler according to any one of (1) to (3) above, wherein the third heat conducting particle comprises at least one selected from the group consisting of aluminum nitride, alumina, and silica.

[0014] (5) The heat dissipation filler according to any one of (1) to (4) above, wherein the length of the fibrous aluminum nitride in the longitudinal direction is 1.0 μm or more and 5.0 cm or less.

[0015] (6) The heat dissipation filler according to any one of (1) to (5) above, wherein the length of the fibrous aluminum nitride in the short axis direction is 0.5 μm or more and 50.0 μm or less.

[0016] (7) The heat dissipation filler according to any one of (1) to (6) above, wherein the aspect ratio of the fibrous aluminum nitride is 2 or more and 200 or less.

[0017] (8) A resin composition used in the manufacture of a resin molded article composed of a resin material, characterized in that it contains a heat dissipation filler as described in any of (1) to (7) above.

[0018] (9) The resin composition according to (8) above, further comprising a viscosity modifier in addition to the heat dissipation filler and the resin material, wherein the sum of the content of the resin material and the content of the viscosity modifier in the resin composition is 4.0% by mass or more and 7.0% by mass or less.

[0019] (10) The resin composition according to (9) above, comprising silicone oil as the viscosity modifier.

[0020] (11) The resin composition according to any one of (8) to (10) above, comprising a silicone resin as the resin material.

[0021] (12) A resin molded article made of a material including a resin material, characterized in that it includes a heat dissipation filler as described in any of (1) to (7) above.

[0022] (13) The resin molded article according to (12), further comprising a viscosity modifier in addition to the heat dissipation filler and the resin material, wherein the sum of the content of the resin material and the content of the viscosity modifier in the resin molded article is 4.0% by mass or more and 7.0% by mass or less.

[0023] (14) The resin molded article according to (13) above, comprising silicone oil as the viscosity modifier.

[0024] (15) A resin molded article according to any one of (12) to (14) above, wherein the resin material includes a silicone resin.

[0025] (16) A resin molded article according to any one of (12) to (15) above, wherein the thermal conductivity in three mutually orthogonal axial directions is 4.0 W / m·K or more and 20 W / m·K or less in all of them.

[0026] (17) A resin molded article according to any one of (12) to (16) above, wherein the withstand voltage is 1 kV / mm or more and 100 kV / mm or less.

[0027] According to the present invention, it is possible to provide a heat dissipation filler that can be suitably used in the manufacture of a resin molded article having excellent overall thermal conductivity, for example, excellent thermal conductivity not only in the in-plane direction but also in the thickness direction; a resin composition that can be suitably used in the manufacture of a resin molded article having excellent overall thermal conductivity, for example, excellent thermal conductivity not only in the in-plane direction but also in the thickness direction; and a resin molded article that has excellent overall thermal conductivity, for example, excellent thermal conductivity not only in the in-plane direction but also in the thickness direction.

[0028] Figure 1 is a schematic diagram illustrating one example of the configuration of a heat dissipation filler and a resin molded body. Figure 2 is a schematic diagram illustrating one example of how the resin molded body shown in Figure 1 can be used.

[0029] The following describes preferred embodiments of the present invention in detail. [1] Heat dissipation filler First, the heat dissipation filler of the present invention will be described.

[0030] Figure 1 is a schematic diagram illustrating one example of the configuration of the heat dissipation filler and resin molded body of the present invention.

[0031] The heat dissipation filler 10 of the present invention is a heat dissipation filler used in the manufacture of a resin molded body 1, and contains first heat conductive particles 12 with a particle size of 50 μm or more and 300 μm or less, second heat conductive particles 13 with a particle size of 5 μm or more and less than 50 μm, third heat conductive particles 14 with a particle size of 0.1 μm or more and less than 5 μm, and fibrous aluminum nitride 11.

[0032] Furthermore, the heat dissipation 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, the third heat conductive particles 14, and the fibrous aluminum nitride 11 is 100.0 parts by volume, the first heat conductive particles 12 are contained in an amount of 40.0 to 70.0 parts by volume, the second heat conductive particles 13 are contained in an amount of 7.0 to 30.0 parts by volume, the third heat conductive particles 14 are contained in an amount of 22.0 to 45.0 parts by volume, and the fibrous aluminum nitride 11 is contained in an amount of 0.5 to 13.5 parts by volume.

[0033] Since the heat dissipation filler 10 of the present invention contains fibrous aluminum nitride 11, a large number of heat transfer paths are suitably formed by the multiple fibrous aluminum nitride 11.

[0034] Furthermore, the heat dissipation filler 10 of the present invention contains, in a predetermined proportion, first heat conductive particles 12 with a relatively large particle size, third heat conductive particles 14 with a relatively small particle size, and second heat conductive particles 13 with a particle size of medium size between these two. This allows the first heat conductive particles 12 to penetrate into the gaps between the relatively large fibrous aluminum nitride 11, and further, the second heat conductive particles 13 and the third heat conductive particles 14 to penetrate into the gaps between the fibrous aluminum nitride 11 and the first heat conductive particles 12. (More specifically, the first heat conduction particles 12 can enter into the gaps between the relatively large fibrous aluminum nitride 11, the second heat conduction particles 13 can enter into the gaps between the fibrous aluminum nitride 11 and the first heat conduction particles 12, and furthermore, the third heat conduction particles 14 can enter into the gaps between the fibrous aluminum nitride 11, the first heat conduction particles 12 and the second heat conduction particles 13.) As a result, the fibrous aluminum nitride 11 and the first heat conduction particles 12, the second heat conduction particles 13 and the third heat conduction particles 14 are densely packed, and a larger number of heat transfer paths are suitably formed, thereby increasing thermal conductivity.

[0035] In particular, by including first heat-conducting particles 12, second heat-conducting particles 13, and third heat-conducting particles 14 in predetermined proportions in addition to the fibrous aluminum nitride 11, it is possible to suitably form heat transfer paths not only in the in-plane direction but also in the thickness direction of the resin molded body 1, thereby achieving excellent thermal conductivity for the resin molded body 1 as a whole. In particular, even resin molded bodies 1 with a large thickness can be made to have excellent thermal conductivity in the thickness direction.

[0036] In this specification, the particle sizes of the heat-conducting particles (first heat-conducting particle 12, second heat-conducting particle 13, and third heat-conducting particle 14) can be determined by image analysis from magnified images obtained by a scanning electron microscope (SEM).

[0037] Furthermore, in this invention, thermal conductive particles refer to particles composed of a material whose thermal conductivity at 25°C is 1 W / m·K or higher.

[0038] Furthermore, by including the first heat-conducting particles 12, the second heat-conducting particles 13, and the third heat-conducting particles 14 in a predetermined proportion, the fibrous aluminum nitride 11 can exist in a state with less bending during the molding process of the resin molded body 1, thus making it easier to secure heat transfer paths.

[0039] Furthermore, the above configuration makes it possible to achieve excellent mechanical strength in the resin molded body 1 manufactured using the heat dissipation filler 10 of the present invention. It also effectively prevents the hardness of the resin molded body 1 from becoming too high. As a result, the thermal conductivity of the resin molded body 1 as a whole can be made sufficiently excellent. In addition, the moldability during the manufacturing of the resin molded body 1 can be improved.

[0040] Conversely, if the above conditions are not met, satisfactory results cannot be obtained. For example, even if the heat dissipation filler 10 contains a first heat conductive particle 12, a second heat conductive particle 13, and a third heat conductive particle 14, if it does not contain fibrous aluminum nitride 11, it is not possible to suitably form heat transfer paths, particularly in-plane heat transfer paths, in the resin molded body 1 manufactured using the heat dissipation filler 10, and the overall thermal conductivity of the resin molded body 1 manufactured using the heat dissipation filler 10 cannot be made sufficiently excellent.

[0041] Furthermore, even if the heat dissipation filler 10 contains fibrous aluminum nitride 11, if it does not contain all of the first heat conductive particles 12, the second heat conductive particles 13, and the third heat conductive particles 14 as heat conductive particles, it is not possible to create the filling structure described above, and it is not possible to suitably form the heat transfer paths, particularly the heat transfer paths in the thickness direction, of the resin molded body 1 manufactured using the heat dissipation filler 10, and the overall heat conductivity of the resin molded body 1 manufactured using the heat dissipation filler 10 cannot be made sufficiently excellent.

[0042] Further, even if the fibrous aluminum nitride 11, the second heat conductive particles 13, and the third heat conductive particles 14 are included, if the first heat conductive particles 12 are not included, or even if the fibrous aluminum nitride 11, the first heat conductive particles 12, and the second heat conductive particles 13 are included, but instead of the third heat conductive particles 14, heat conductive particles with a smaller particle size are included, the heat transfer path of the resin molded body 1 manufactured using the heat dissipation filler 10 cannot be suitably formed, and the overall thermal conductivity cannot be made sufficiently excellent.

[0043] Further, even if the fibrous aluminum nitride 11, the first heat conductive particles 12, and the second heat conductive particles 13 are included, if the third heat conductive particles 14 are not included, or even if the fibrous aluminum nitride 11, the second heat conductive particles 13, and the third heat conductive particles 14 are included, but instead of the first heat conductive particles 12, heat conductive particles with a larger particle size are included, the filling structure as described above cannot be achieved, and the heat transfer path of the resin molded body 1 manufactured using the heat dissipation filler 10 cannot be suitably formed.

[0044] Further, even if the fibrous aluminum nitride 11, the first heat conductive particles 12, and the third heat conductive particles 14 are included, if the second heat conductive particles 13 are not included, efficient filling cannot be achieved, and the balance between the thermal conductivity and the mechanical strength cannot be maintained.

[0045] Further, when the content of the first heat conductive particles 12 is less than the above lower limit value, there is insufficient space for the second heat conductive particles 13 to enter the first heat conductive particles 12. As a result, when the second heat conductive particles 13 are filled between the first heat conductive particles 12, unnecessary interfacial resistance is increased, and an efficient filling structure cannot be achieved. Consequently, the heat transfer path of the resin molded body 1 manufactured using the heat dissipation filler 10 cannot be suitably formed, and the overall thermal conductivity cannot be made sufficiently excellent.

[0046] Further, when the content of the first heat-conductive particles 12 exceeds the upper limit value, there is insufficient space for the first heat-conductive particles 12 to penetrate into the fibrous aluminum nitride 11. As a result, when the first heat-conductive particles are filled between the fibrous aluminum nitrides 11, the degree of freedom of the particles with high viscous resistance becomes high. Consequently, an efficient filling structure cannot be achieved, the hardness of the resin molded body 1 manufactured using the heat dissipation filler 10 increases, and the balance between the thermal conductivity and the mechanical strength cannot be maintained.

[0047] Further, when the content of the second heat-conductive particles 13 is less than the lower limit value, efficient filling cannot be achieved, and the balance between the thermal conductivity and the mechanical strength cannot be maintained. Also, the moldability may decrease or the hardness may become too high.

[0048] Further, when the content of the second heat-conductive particles 13 exceeds the upper limit value, efficient filling cannot be achieved, and the balance between the thermal conductivity and the mechanical strength cannot be maintained.

[0049] Further, when the content of the third heat-conductive particles 14 is less than the lower limit value, the number of the third heat-conductive particles 14 decreases, the space for the third heat-conductive particles 14 to penetrate into the second heat-conductive particles 13 increases, and a dense filling structure cannot be achieved. As a result, the heat transfer path of the resin molded body 1 manufactured using the heat dissipation filler 10 cannot be preferably formed, and the overall thermal conductivity cannot be made sufficiently excellent. Also, since the degree of freedom of the large particles becomes high, the hardness of the resin molded body 1 manufactured using the heat dissipation filler 10 increases.

[0050] Further, when the content of the third heat-conductive particles 14 exceeds the upper limit value, there is insufficient space for the third heat-conductive particles 14 to penetrate into the second heat-conductive particles 13. As a result, when the third heat-conductive particles are filled between the second heat-conductive particles 12, unnecessary interfacial resistance is increased. Consequently, the heat transfer path of the resin molded body 1 manufactured using the heat dissipation filler 10 cannot be preferably formed, and the overall thermal conductivity cannot be made sufficiently excellent.

[0051] Furthermore, if the content of fibrous aluminum nitride 11 is below the above lower limit, the heat transfer paths of the resin molded body 1 manufactured using the heat dissipation filler 10, particularly the heat transfer paths in the in-plane direction, cannot be made sufficient. In addition, the hardness of the resin molded body 1 may increase, and the moldability of the resin molded body 1 may decrease.

[0052] Furthermore, if the content of fibrous aluminum nitride 11 exceeds the upper limit, the hardness of the resin molded body 1 manufactured using the heat dissipation filler 10 becomes significantly higher, and the moldability of the resin molded body 1 decreases.

[0053] [1-1] The first heat-conducting particle The first heat-conducting particle will be described below.

[0054] The first heat-conducting particle 12 is composed of a material that has thermal conductivity and has a particle size of 50 μm or more and 300 μm or less.

[0055] Examples of materials constituting the first heat-conducting particle 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 graphite; and metals such as aluminum, copper, nickel, and silver. One or more of these can be selected and used in combination.

[0056] Furthermore, if electrical insulation is required for the heat dissipation filler 10 or the resin molded body 1, it is preferable that at least one is selected from the group consisting of metal oxides, metal hydroxides, and nitrides, and it may be an amphoteric hydroxide or amphoteric oxide. Specifically, 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 can be used in combination.

[0057] In particular, the material constituting the first heat-conducting particle 12 preferably includes at least one selected from the group consisting of aluminum nitride and boron nitride.

[0058] This makes it possible to improve the thermal conductivity of the heat dissipation filler 10 and the resin molded body 1 manufactured using the heat dissipation filler 10.

[0059] Furthermore, because these materials have excellent thermal conductivity and high electrical insulation properties, the manufactured resin molded body 1 can be suitably applied, for example, as a heat dissipation component in electronic devices or other applications requiring higher insulation.

[0060] Furthermore, by using aluminum nitride, the thermal conductivity of the aluminum nitride itself is high, and the thermal resistance between it and the fibrous aluminum nitride 11 can be more effectively suppressed. Therefore, the thermal conductivity of the heat dissipation filler 10 and the resin molded body 1 manufactured using the heat dissipation filler 10 can be made particularly high.

[0061] Furthermore, using boron nitride can improve heat dissipation. Boron nitride also has high chemical stability and excellent environmental resistance.

[0062] Furthermore, alumina is chemically stable, readily available, and relatively inexpensive, allowing for a stable supply and contributing to reduced manufacturing costs. It also allows for higher strength in the resin molded body 1.

[0063] The particle size of the first heat-conducting particle 12 may be 50 μm or more and 300 μm or less, but the average particle size of the first heat-conducting particle 12 is preferably 60 μm or more and 250 μm or less, more preferably 70 μm or more and 200 μm or less, and even more preferably 80 μm or more and 150 μm or less. This makes the effects of the present invention described above even more pronounced.

[0064] In this specification, unless otherwise specified, the average particle size refers to the particle size at which the frequency of the particle quantity, calculated cumulatively from the smallest particle size, reaches 50% in a particle distribution measured by image analysis. This can be determined, for example, by measurement using the particle shape image analyzer "PITA-04" (manufactured by Seishin Corporation).

[0065] In the heat dissipation filler 10, when the total amount of the first heat conductive particles 12, the second heat conductive particles 13, the third heat conductive particles 14, and the fibrous aluminum nitride 11 is 100.0 parts by volume, the first heat conductive particles 12 may be present in a proportion of 40.0 parts by volume or more and 70.0 parts by volume or less, but it is preferable that they be present in a proportion of 45.0 parts by volume or more and 65.0 parts by volume or less, and more preferably that they be present in a proportion of 50.0 parts by volume or more and 60.0 parts by volume or less. This makes the effects of the present invention described above even more pronounced.

[0066] [1-2] The second heat-conducting particle will be described below.

[0067] The second heat-conducting particle 13 is composed of a material that has thermal conductivity and has a particle size of 5 μm or more and less than 50 μm.

[0068] The materials constituting the second heat-conducting particles 13 are the same as those constituting the first heat-conducting particles 12 described above, but it is preferable that the second heat-conducting particles 13 include at least one selected from the group consisting of aluminum nitride and boron nitride.

[0069] This makes it possible to improve the thermal conductivity of the heat dissipation filler 10 and the resin molded body 1 manufactured using the heat dissipation filler 10.

[0070] Furthermore, because these materials have excellent thermal conductivity and high electrical insulation properties, the manufactured resin molded body 1 can be applied, for example, as a heat dissipation component in electronic devices or other applications where higher insulation is required.

[0071] In particular, by using aluminum nitride, the thermal conductivity of heat dissipation fillers, resin compositions containing heat dissipation fillers, and resin molded articles can be further improved.

[0072] Furthermore, using boron nitride can improve the moisture resistance of heat dissipation fillers, resin compositions containing heat dissipation fillers, and molded resin products. It is also advantageous in reducing the cost of heat dissipation fillers, resin compositions containing heat dissipation fillers, and molded resin products.

[0073] Furthermore, using alumina can improve the moisture resistance of heat dissipation fillers, resin compositions containing heat dissipation fillers, and molded resin products. It is also advantageous in reducing the cost of heat dissipation fillers, resin compositions containing heat dissipation fillers, and molded resin products.

[0074] Furthermore, by using silica, the moisture resistance of heat dissipation fillers, resin compositions containing heat dissipation fillers, and resin molded articles can be improved. In addition, the thermal expansion coefficient of heat dissipation fillers and resin molded articles containing heat dissipation fillers can be brought closer to that of the target object such as semiconductor elements, thereby more effectively achieving stress relaxation on the target object when the resin molded article containing heat dissipation filler is applied. This is also advantageous in terms of reducing the cost of heat dissipation fillers, resin compositions containing heat dissipation fillers, and resin molded articles.

[0075] The particle size of the second heat-conducting particle 13 may be 5 μm or more and less than 50 μm, but the average particle size of the second heat-conducting particle 13 is preferably 7 μm or more and 40 μm or less, more preferably 10 μm or more and 35 μm or less, and even more preferably 15 μm or more and 30 μm or less. This makes the effects of the present invention described above even more pronounced.

[0076] In the heat dissipation filler 10, when the total amount of the first heat conductive particles 12, the second heat conductive particles 13, the third heat conductive particles 14, and the fibrous aluminum nitride 11 is 100.0 parts by volume, the second heat conductive particles 13 may be present in an amount of 7.0 parts by volume or more and 30.0 parts by volume or less, but it is preferable that it be present in an amount of 8.0 parts by volume or more and 28.0 parts by volume or less, more preferably 9.0 parts by volume or more and 26.0 parts by volume or less, and even more preferably 10.0 parts by volume or more and 25.0 parts by volume or less. This makes the effects of the present invention described above even more pronounced.

[0077] [1-3] The third heat-conducting particle The third heat-conducting particle will be described below.

[0078] The third heat-conducting particle 14 is composed of a material that has thermal conductivity and has a particle size of 0.1 μm or more and less than 5 μm.

[0079] The materials constituting the third heat-conducting particles 14 are the same as those constituting the first heat-conducting particles 12 and the second heat-conducting particles 13 described above, but it is preferable that the third heat-conducting particles 14 include at least one selected from the group consisting of aluminum nitride, alumina, and silica.

[0080] This makes it possible to improve the thermal conductivity of the heat dissipation filler 10 and the resin molded body 1 manufactured using the heat dissipation filler 10.

[0081] Because these materials have excellent thermal conductivity and high electrical insulation properties, the manufactured resin molded body 1 can be applied, for example, as a heat dissipation component in electronic devices or other applications where higher insulation is required.

[0082] In particular, since silica has thermal expansion properties similar to those of silicon-based semiconductor substrates, the resin molded body 1 can be more suitably applied as a heat dissipation member for, for example, an electronic device.

[0083] The particle size of the third heat-conducting particle 14 may be 0.1 μm or more and less than 5 μm, but the average particle size of the third heat-conducting particle 14 is preferably 0.2 μm or more and 4.0 μm or less, more preferably 0.3 μm or more and 3.0 μm or less, and even more preferably 0.4 μm or more and 2.0 μm or less. This makes the effects of the present invention described above even more pronounced.

[0084] In the heat dissipation filler 10, when the total amount of the first heat conductive particles 12, the second heat conductive particles 13, the third heat conductive particles 14, and the fibrous aluminum nitride 11 is 100.0 parts by volume, the third heat conductive particles 14 may be present in a proportion of 22.0 parts by volume or more and 45.0 parts by volume or less, but it is preferable that it be present in a proportion of 24.0 parts by volume or more and 43.0 parts by volume or less, more preferably 26.0 parts by volume or more and 40.0 parts by volume or less, and even more preferably 27.0 parts by volume or more and 37.0 parts by volume or less. This makes the effects of the present invention described above even more pronounced.

[0085] [1-4] Fibrous aluminum nitride The following describes fibrous aluminum nitride.

[0086] Aluminum nitride is a material that possesses both high thermal conductivity and high insulating properties. Furthermore, the fibrous aluminum nitride 11 plays an important role in improving thermal conductivity by forming heat dissipation paths that enhance the contact efficiency between fillers in the resin molded body 1. It is also an important component in improving the flexibility, transparency, and moldability of the resin molded body 1.

[0087] The fibrous aluminum nitride 11 may be polycrystalline, but it is preferable that it is composed of single-crystal whiskers.

[0088] Since single-crystal whiskers have a higher thermal conductivity than polycrystalline materials, the thermal conductivity of the heat dissipation filler 10 and the resin molded body 1 manufactured using the heat dissipation filler 10 can be made higher.

[0089] Furthermore, by using high-purity single-crystal whiskers as the fibrous aluminum nitride 11, the thermal conductivity can be increased compared to polycrystalline materials with many impurities, and the volume fraction of the fibrous aluminum nitride 11 can be reduced.

[0090] This makes it possible to maintain the mechanical properties of the resin molded body 1, such as flexibility, especially when the resin molded body 1 is in the form of a sheet.

[0091] Furthermore, the single-crystal whisker used as the fibrous aluminum nitride 11 preferably has a hexagonal wurtzite-type crystal structure, with the (0002) plane positioned perpendicular to the c-axis direction. Such a single-crystal whisker can achieve a thermal conductivity of 120 W / m·K or more and 320 W / m·K or less.

[0092] Furthermore, in this embodiment, the single-crystal whisker (AlN whisker) as the fibrous aluminum nitride 11 may include a fibrous aluminum nitride 11 single crystal body and an oxygen-containing layer that covers the surface of the aluminum nitride single crystal body in a cylindrical shape. In addition, each of the fibrous aluminum nitride 11 may include a hydrophobic layer that covers the oxygen-containing layer in a cylindrical shape, further outside the oxygen-containing layer.

[0093] Details of the structure of such fibrous aluminum nitride 11, manufacturing methods, etc., are publicly known from, for example, Japanese Patent Publication No. 2014-73951 and Japanese Patent Publication No. 2018-154534, so a detailed explanation of these will be omitted.

[0094] The length of the fibrous aluminum nitride 11 in the longitudinal direction 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.

[0095] This increases the number of contact points between the fibrous aluminum nitride 11. As a result, more heat transfer paths can be secured through contact between the fibrous aluminum nitride 11, and the thermal conductivity of the heat dissipation filler 10 and the resin molded body 1 manufactured using the heat dissipation filler 10 can be improved. In addition, the mechanical strength of the resin molded body 1 can be improved.

[0096] The length of the fibrous aluminum nitride 11 in the short axis direction 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.

[0097] As a result, numerous heat transfer paths are suitably formed by the multiple fibrous aluminum nitride 11, making it possible to improve the thermal conductivity of the heat dissipation filler 10 and the resin molded body 1 manufactured using the heat dissipation filler 10. Furthermore, the mechanical strength of the resin molded body 1 can be improved.

[0098] The lengths of the fibrous aluminum nitride 11 in the long and short axes can be measured by image analysis from magnified images obtained with a scanning electron microscope (SEM).

[0099] The aspect ratio (the length in the long axis direction divided by the length in the short axis direction) of the fibrous aluminum nitride 11 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.

[0100] This makes it possible to more efficiently increase the contact density per unit volume between fibrous aluminum nitride 11 particles, and even with a relatively small amount of this material, high thermal conductivity can be imparted to the resin molded body 1. Furthermore, for example, when the resin molded body 1 is in the form of a sheet, the mechanical properties of the resin molded body 1, such as flexibility, can be made more favorable. In addition, the mechanical strength of the resin molded body 1 can be made superior.

[0101] Furthermore, if the aspect ratio exceeds the above upper limit, the fibrous aluminum nitride 11 is more likely to break or be damaged during the manufacturing of the resin molded body 1, which may increase the amount of fine powder.

[0102] In the heat dissipation filler 10, when the total amount of the first heat conductive particles 12, the second heat conductive particles 13, the third heat conductive particles 14, and the fibrous aluminum nitride 11 is 100.0 parts by volume, the fibrous aluminum nitride 11 may be present in a proportion of 0.5 parts by volume or more and 13.5 parts by volume or less, but it is preferable that it be present in a proportion of 1.5 parts by volume or more and 12.0 parts by volume or less, more preferably 2.5 parts by volume or more and 11.0 parts by volume or less, and even more preferably 3.5 parts by volume or more and 10.0 parts by volume or less. This makes the effects of the present invention described above even more pronounced.

[0103] [1-5] Other Components The heat dissipation filler 10 may contain other components in addition to the fibrous aluminum nitride 11, the first heat conductive particles 12, the second heat conductive particles 13, and the third heat conductive particles 14 described above. Hereinafter in this section, such components will be referred to as "other components".

[0104] Other components include, for example, thermal conductive particles with a particle size of less than 0.1 μm, thermal conductive particles with a particle size of more than 300 μm, and thermal conductive fibers made of materials other than aluminum nitride.

[0105] However, the content of other components in the heat dissipation 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.

[0106] [1-6] Other conditions The heat dissipation filler of the present invention preferably satisfies the following conditions.

[0107] In other words, it is preferable that no fracture is observed when a resin composition is obtained by mixing the heat dissipation filler of the present invention with a silicone resin as a resin material (for example, TSE3431 manufactured by Momentive Corporation) and a silicone oil as a viscosity modifier (for example, KF-96A-100CS manufactured by Shin-Etsu Silicone Co., Ltd.) in the following proportions: 95.6% by mass, 3.1% by mass, and 1.3% by mass, respectively, and then treating each resin composition at 100°C for 60 minutes to obtain a resin molded body with a diameter of 45 mm and a thickness of 1.0 mm, and then performing a tensile test in accordance with JIS K 7161 and a compression test in accordance with JIS K 7181. This makes it possible to manufacture a resin molded body with superior mechanical strength using the heat dissipation filler of the present invention. In particular, it is possible to manufacture a resin molded body that is not too hard, has excellent overall thermal conductivity, and possesses superior mechanical strength.

[0108] Furthermore, each resin composition obtained by mixing the heat dissipation filler of the present invention with a silicone resin as a resin material (e.g., Momentive Co., Ltd., TSE3431) and a silicone oil as a viscosity modifier (e.g., Shin-Etsu Silicone Co., Ltd., KF-96A-100CS) in content amounts of 95.6% by mass, 3.1% by mass, and 1.3% by mass, respectively, is treated at 100°C for 60 minutes to obtain a resin molded body with a square diameter of 50 mm and a thickness of 1.0 mm. Six of these resin molded bodies are stacked together, and the hardness (Shore OO hardness) measured according to ASTM D2240 TYPEOO is preferably less than 85, more preferably less than 80, and even more preferably less than 70. This makes it possible to manufacture a resin molded body with more appropriate hardness using the heat dissipation filler of the present invention. In particular, it is possible to manufacture a resin molded body with superior overall thermal conductivity and mechanical strength, as well as sufficiently low hardness.

[0109] Furthermore, it is preferable to obtain resin compositions by mixing the heat dissipation filler of the present invention with a silicone oil for moldability evaluation (for example, KF-96A-100CS manufactured by Shin-Etsu Silicone Co., Ltd.) in amounts of 95.6% by mass and 4.4% by mass, respectively, and then using a rheometer (rotational viscometer manufactured by Thermo Fisher Scientific, Inc.), the kinematic viscosity at 25°C of the resin composition is less than 100,000 mPa, and no shedding of the heat dissipation filler is observed in the obtained resin composition. This makes it possible to improve the moldability of the resin composition containing the heat dissipation filler of the present invention. In particular, it is possible to manufacture resin molded articles with superior overall thermal conductivity and mechanical strength, as well as sufficiently low hardness, with excellent moldability.

[0110] [2] Resin Composition Next, the resin composition of the present invention will be described.

[0111] The present invention is a resin composition used in the manufacture of a resin molded article 1 composed of a material including a resin material 20, and is characterized by containing the above-described heat dissipation filler 10.

[0112] As a result, the resin molded body 1 manufactured using the resin composition has numerous heat transfer paths suitably formed by the heat dissipation filler 10, resulting in excellent overall thermal conductivity, and for example, excellent thermal conductivity not only in the in-plane direction but also in the thickness direction. In particular, even resin molded bodies 1 with a large thickness can have excellent thermal conductivity in the thickness direction. Furthermore, the mechanical strength of the resin molded body 1 manufactured using the resin composition can be improved.

[0113] [2-1] Heat dissipation filler The resin composition of the present invention includes the heat dissipation filler 10 described above.

[0114] The content of the heat dissipation filler 10 in the resin composition is preferably 93% by mass or more and 96% by mass or less.

[0115] This makes it possible to more favorably achieve both the effect of improving the thermal conductivity of the resin molded article 1 manufactured using the resin composition, thereby reducing the overall thermal resistance, and the effect of improving the moldability of the resin molded article 1. Furthermore, it is possible to improve the mechanical strength of the resin molded article 1 manufactured using the resin composition.

[0116] [2-2] Resin material The resin composition of the present invention comprises a resin material 20.

[0117] As the resin material 20, for example, thermosetting resins such as silicone resin, epoxy resin, phenolic resin, melamine resin, urea resin, thermosetting polyimide, unsaturated polyester resin, and polyurethane can be used.

[0118] Among these, it is particularly preferable that the composition contains a silicone resin. This makes it possible to improve the chemical stability, heat resistance, and other properties of the resin composition and the resin molded article 1 produced using the resin composition.

[0119] Examples of silicone resins include dimethyl silicone, epoxy group-containing silicone, mercapto group-containing silicone, MQ resin, acrylic silicone resin, polyester silicone resin, epoxy silicone resin, mercapto silicone resin, silicone rubber, and silicone elastomer.

[0120] Furthermore, as the resin material 20, thermoplastic resins such as polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, acrylonitrile styrene copolymer, acrylonitrile butadiene styrene copolymer, acrylonitrile ethylene propylene diene styrene copolymer, and methacrylic resin can be used.

[0121] Furthermore, as the resin material 20, for example, fluororesins such as polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride, and polyvinyl fluoride can be used.

[0122] Furthermore, as the resin material 20, for example, polycarbonate, polyamide resin, polyacetal, polyethylene terephthalate, polybutylene terephthalate, polyetheretherketone, polyphenyl sulfide, polysulfone, polyetherimide, polyamideimide, thermoplastic polyimide, liquid crystal polymer, etc. can be used.

[0123] Furthermore, as the resin material 20, for example, 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, perfluororub, tetrafluoroethylene-hexafluoropropylene copolymer, flexible urethane foam, etc. can be used.

[0124] Furthermore, as the resin material 20, for example, glass fiber reinforced plastic, glass fiber reinforced thermoplastic, butyl rubber, ionomer, isoprene rubber, melamine formaldehyde, methyl methacrylate, nitrile rubber, natural rubber, polyacrylic acid, polyallyl ether ketone, polyester alkyd resin, polyacrylonitrile, polyarylate, etc. can be used.

[0125] Furthermore, as the resin material 20, for example, poly(p-phenylenebenzobisoxazole), polybutadiene styrene, diallyl terephthalate, polydicyclopentadiene, polyethylene naphthalate, polyethylene oxide, polyethersulfone, phenol formaldehyde, tetrafluoroethylene perfluoroalkyl vinyl ether copolymer, polyisobutylene, polymethylpentene, etc. can be used.

[0126] Furthermore, as the resin material 20, for example, polyphthalamide, polyphenylene ether, polyphenylene oxide, polytrimethylene terephthalate, reactive polyurethane, polyvinyl alcohol, polyvinyl butyral, acrylic-modified polyvinyl chloride, polyvinyl dichloride, vinyl chloride vinyl acetate copolymer, and the like can be used.

[0127] Furthermore, as the resin material 20, for example, 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, crosslinked polyethylene, etc. can be used.

[0128] As the resin material 20, for example, one or more of the materials exemplified above can be used in combination.

[0129] The content of the resin material 20 in the resin composition is preferably 12.3% by volume or more and 20.2% by volume or less.

[0130] This makes it possible to more effectively 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 improving the moldability of the resin molded body 1. Furthermore, it is possible to improve the mechanical strength of the resin molded body 1 manufactured using the resin composition.

[0131] The content of the resin material 20 in the resin composition is preferably 4% by mass or more and 7% by mass or less.

[0132] This makes it possible to more effectively 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 improving the moldability of the resin molded body 1. Furthermore, it is possible to improve the mechanical strength of the resin molded body 1 manufactured using the resin composition.

[0133] When the resin material 20 constituting the resin composition contains silicone resin, the proportion of silicone resin in the total resin material 20 is preferably 50% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more. This allows the aforementioned effects to be exhibited more significantly.

[0134] [2-3] Viscosity modifier The resin composition of the present invention may contain the heat dissipation filler 10 and resin material 20 described above, but it is preferable that it further contains a viscosity modifier.

[0135] This allows for a reduction in the crosslinking density of the base resin, thereby lowering the viscosity of the resin composition and improving the compressive properties of the resin molded article 1 produced using the resin composition.

[0136] While not particularly limited, silicone oil is preferred as the viscosity modifier.

[0137] This allows for a more favorable reduction in the crosslinking density of the base resin, thereby more favorable reduction in the viscosity of the resin composition, and further improvement in the compressive properties of the resin molded article 1 produced using the resin composition. Furthermore, when silicone oil is used in combination with silicone resin as a viscosity modifier, the aforementioned effects are exhibited even more significantly.

[0138] Examples of silicone oils include dimethylpolysiloxane and diphenylpolysiloxane.

[0139] If the resin composition contains a viscosity modifier, the content of the viscosity modifier in the resin composition is preferably more than 0% by mass and 5.6% by mass or less.

[0140] This makes it possible to further improve the compression characteristics of the resin molded article 1 manufactured using the resin composition.

[0141] When the viscosity modifier constituting the resin composition contains silicone oil, the proportion of silicone oil in the total viscosity modifier is preferably 50% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more. This allows the aforementioned effects to be exhibited more significantly.

[0142] If the resin composition contains a viscosity modifier, the sum of the content of the resin material 20 and the content of the viscosity modifier in the resin composition is preferably 4.0% by mass or more and 7.0% by mass or less, more preferably 4.5% by mass or more and 6.8% by mass or less, and even more preferably 5.0% by mass or more and 6.5% by mass or less.

[0143] This makes it possible to more effectively 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 improving the moldability of the resin molded body 1. Furthermore, it is possible to improve the mechanical strength of the resin molded body 1 manufactured using the resin composition.

[0144] [2-4] Other Components The resin composition of the present invention may contain components other than those described above. Hereinafter, in this section, such components will also be referred to as "other components".

[0145] Other components include, for example, plasticizers, colorants, antioxidants, ultraviolet absorbers, light stabilizers, modifiers, rust inhibitors, fillers other than the heat dissipation filler of the present invention as described above, fillers, electromagnetic wave absorbers, surface lubricants, corrosion inhibitors, heat stabilizers, lubricants, primers, antistatic agents, polymerization inhibitors, crosslinking agents, catalysts, leveling agents, dispersants, anti-aging agents, flame retardants, hydrolysis inhibitors, corrosion inhibitors, etc.

[0146] 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.

[0147] [3] Resin molded body Next, the resin molded body 1 of the present invention will be described.

[0148] The resin molded body 1 of the present invention is a resin molded body 1 composed of a material including a resin material 20, and is characterized by including the heat dissipation filler 10 described above.

[0149] As a result, the resin molded body 1 has a number of suitable heat transfer paths formed by the heat dissipation filler 10 described above, which can reduce the overall thermal resistance and, for example, improves thermal conductivity not only in the in-plane direction but also in the thickness direction. In particular, even a resin molded body 1 with a large thickness can have excellent thermal conductivity in the thickness direction. Furthermore, the mechanical strength of the resin molded body 1 can be improved.

[0150] The resin molded article 1 can be suitably manufactured, for example, using the resin composition of the present invention described above. Furthermore, in the manufacture of the resin molded article 1, a combination of multiple resin compositions of the present invention may be used. In addition, the resin molded article 1 may be manufactured using other components or compositions in addition to the resin composition of the present invention described above. Examples of such other components or compositions include resin materials for dilution.

[0151] [3-1] Heat dissipation filler The resin molded article 1 of the present invention includes the heat dissipation filler 10 described above.

[0152] The content of the heat dissipation filler 10 in the resin molded body 1 is preferably 93% by mass or more and 96% by mass or less.

[0153] This improves the overall thermal conductivity of the resin molded body 1, thereby more effectively achieving both the effect of reducing thermal resistance and the effect of improving the moldability of the resin molded body 1. Furthermore, it improves the mechanical strength of the resin molded body 1.

[0154] [3-2] Resin material The resin molded article 1 of the present invention includes the resin material 20 described above.

[0155] In particular, it is preferable that the resin molded body 1 contains silicone resin as the resin material 20.

[0156] The content of the resin material 20 in the resin molded body 1 is preferably 4% by weight or more and 7% by weight or less.

[0157] This improves the overall thermal conductivity of the resin molded body 1, thereby more effectively achieving both the effect of reducing thermal resistance and the effect of improving the moldability of the resin molded body 1. Furthermore, it improves the mechanical strength of the resin molded body 1.

[0158] [3-3] Viscosity modifier The resin molded article 1 of the present invention may contain the viscosity modifier described above.

[0159] This makes it possible to improve the compression characteristics of the resin molded body 1.

[0160] In particular, if the resin molded article 1 of the present invention contains silicone oil as a viscosity modifier, the crosslinking density can be more favorably reduced when a silicone resin is used as the resin material. This allows for a more favorable reduction in the viscosity of the resin composition, and further improves the compressive properties of the resin molded article 1 manufactured using the resin composition.

[0161] The viscosity modifier content in the resin molded body 1 is preferably 4% by mass or more and 7% by mass or less.

[0162] This makes it possible to further improve the compression characteristics of the resin molded body 1.

[0163] If the resin molded body 1 contains a viscosity modifier, it is preferable that the sum of the content of the resin material 20 and the content of the viscosity modifier in the resin molded body 1 be 4.0% by mass or more and 7.0% by mass or less.

[0164] This makes it possible to more effectively 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 improving the moldability of the resin molded body 1. Furthermore, the mechanical strength of the resin molded body 1 can be improved.

[0165] [3-4] Other Components The resin molded article 1 may contain other components in addition to the heat dissipation filler 10 and resin material 20 described above. Hereinafter in this section, such components will also be referred to as "other components".

[0166] Other components include, for example, plasticizers, colorants, antioxidants, ultraviolet absorbers, light stabilizers, modifiers, rust inhibitors, fillers other than the heat dissipation filler of the present invention as described above, fillers, electromagnetic wave absorbers, surface lubricants, corrosion inhibitors, heat stabilizers, lubricants, primers, antistatic agents, polymerization inhibitors, crosslinking agents, catalysts, leveling agents, dispersants, anti-aging agents, flame retardants, hydrolysis inhibitors, corrosion inhibitors, etc.

[0167] However, the content of other components in the resin molded article 1 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.

[0168] [3-5] Other conditions The shape of the resin molded body 1 is not particularly limited and can be, for example, sheet-shaped, block-shaped, etc., depending on the application of the resin molded body 1.

[0169] For example, if the resin molded body 1 is in the form of a sheet, the thickness of the resin molded body 1 is preferably 0.20 mm or more and 20 mm or less.

[0170] As a result, the sheet-like resin molded body 1 can conform well to the surface shape of the member to which it is applied, and the effective thermal conductivity of the resin molded body 1 can be improved. Furthermore, the mechanical strength of the resin molded body 1 can be improved.

[0171] Furthermore, if the resin molded body 1 is in the shape of a block, 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 brought into good contact, resulting in excellent thermal conductivity.

[0172] The resin molded body 1 preferably satisfies the following conditions. For example, the resin molded body 1 preferably has a thermal conductivity of 4.0 W / m·K or more and 20 W / m·K or less in three mutually orthogonal axial directions.

[0173] As a result, the resin molded body 1 has superior thermal conductivity in three mutually orthogonal axial directions.

[0174] For example, if three mutually orthogonal axes are defined as the x-axis, y-axis, and z-axis, respectively, with the x-axis and y-axis representing the in-plane direction of the resin molded body 1 and the z-axis representing the thickness direction of the resin molded body 1, then the resin molded body 1 will have excellent thermal conductivity not only in the in-plane direction but also in the thickness direction.

[0175] Furthermore, the thermal conductivity value can be obtained by using the hot disk method (compliant with ISO 22007-2) with a TPS-2500S manufactured by Kyoto Electronics Manufacturing Co., Ltd.

[0176] Furthermore, the durability voltage of the resin molded body 1 is preferably 1 kV / mm or more and 100 kV / mm or less.

[0177] As a result, for example, when the resin molded body 1 is mounted on an electronic component as a sheet-shaped heat dissipation member, dielectric breakdown can be more effectively suppressed even under high voltage. Therefore, in addition to efficiently transferring heat from a high-temperature component, insulation can be ensured, making the resin molded body 1 more suitable for use as a heat dissipation member in various electronic devices.

[0178] Furthermore, the voltage tolerance can be determined by using a method compliant with JIS C2110-1:2016.

[0179] Furthermore, the withstand voltage can be measured using an dielectric breakdown tester (for example, the YST-243 model manufactured by Yamayo Test Instruments Co., Ltd.).

[0180] [4] Method for manufacturing a resin molded article Next, an example of a method for manufacturing a resin molded article will be described.

[0181] First, a plurality of fibrous aluminum nitride 11 manufactured by a known method, a plurality of first heat conductive particles 12 manufactured by a known method, a plurality of second heat conductive particles 13 manufactured by a known method, and a plurality of third heat conductive particles 14 manufactured by a known method are prepared in advance, and a heat dissipation filler 10 is obtained by mixing them in the proportions described above.

[0182] Next, the obtained heat dissipation filler 10 and the resin material 20 are mixed and kneaded to obtain a resin composition in which the heat dissipation filler 10 is uniformly dispersed.

[0183] Then, the obtained resin composition is molded into a predetermined shape, and the resin material 20 is solidified (cured) to produce the resin molded body 1.

[0184] [5] Forms of Use of Resin Molded Products Next, we will explain the forms of use of resin molded products. Figure 2 is a schematic diagram showing an example of a form of use of the resin molded product shown in Figure 1.

[0185] As described above, the resin molded body 1 has excellent overall thermal conductivity, and for example, it has 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 various heat dissipation members, a heat transfer member that comes into contact with 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 heat from the heat dissipation member, a heat transfer member that comes into contact with an object to be heated and a high-temperature member that is at a higher temperature than the object to be heated, to transfer thermal energy from the high-temperature member to the object to be heated and efficiently heat the object to be heated, and so on.

[0186] The following explanation will primarily focus on the case where a resin molded body is used as a heat conductor, but the uses of the resin molded body of the present invention are not limited to this example.

[0187] As mentioned 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 intended use of the resin molded body 1.

[0188] The following explanation will primarily focus on the case where the resin molded body 1 is used in contact with at least a portion of the surface of a high-temperature component that is a heat-generating element.

[0189] High-temperature components are not particularly limited as long as they become hotter than the surrounding atmosphere. Examples include various electronic and electrical components, more specifically, central processing units (CPUs) of computers, graphics processing units (GPUs), power devices, FPGAs, ASICs, SoCs for smartphones, DSPs and microcontrollers for embedded devices, semiconductor elements such as transistors, light-emitting elements such as laser diodes, light-emitting diodes (LEDs) and electroluminescent devices, liquid crystals, image sensors such as CCDs and image sensors (e.g., 8K), switching regulators, motor coils, and printer heads. High-temperature components may also include relays, batteries, transformers, power supply units, bearings, electron guns, vacuum tubes, and high-frequency oscillators. Furthermore, high-temperature components may include tubes or containers containing a high-temperature fluid.

[0190] As for the high-temperature component, it is preferable that its maximum surface temperature is 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.

[0191] As mentioned above, the resin molded body 1 has excellent overall thermal conductivity, and for example, it has excellent thermal conductivity not only in the in-plane direction but also in the thickness direction, so that it can provide excellent effective thermal conductivity from the high-temperature component to the heat dissipation component. This allows the high-temperature component to be cooled efficiently.

[0192] In the example shown in Figure 2, a sheet-shaped resin molded body 1 is placed between the high-temperature member 100, which is a heat-generating element, and the heat-dissipating member 110, and they are thermally bonded together.

[0193] The resin molded body 1 may be brought into contact with the 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 comes into contact with the high-temperature member and the heat dissipation member, transferring heat from the high-temperature member to the heat dissipation member and efficiently dissipating heat from the heat dissipation member. This makes it possible to improve the heat dissipation efficiency from the high-temperature member.

[0194] The resin molded articles of the present invention described above can also be applied to electronic devices. Such electronic devices may include, for example, electronic components and the resin molded articles of the present invention as heat dissipation members or heat transfer members as described above.

[0195] Examples of electronic devices to which the resin molded article of the present invention is applied include small electronic devices.

[0196] Examples of small electronic devices include notebook computers, tablet devices, mobile communication devices, mobile phones, smartphones, portable music players, portable radios, portable televisions, digital cameras, video cameras, portable game consoles, e-readers, and portable medical devices.

[0197] Although preferred embodiments of the present invention have been described above, the present invention is not limited to those described above.

[0198] For example, the above explanation used the case where the resin molded body is a flat rectangular shape as an example, but the shape of the resin molded body can be appropriately set according to the shape of the component that comes into contact with the resin molded body.

[0199] Furthermore, in the embodiments described above, the resin molded body was typically described as a sheet or block shape with relatively high surface flatness. However, the resin molded body may also be a sheet with stepped surfaces. Such a resin molded body can be suitably used, for example, as a TIM sheet applied to the cooling of components with complex surface shapes, such as CCDs, LEDs, and small sensor modules.

[0200] Furthermore, the resin molded articles of the present invention are not limited to those manufactured by the methods described above. More specifically, for example, the resin molded articles of the present invention are not limited to those manufactured using the heat dissipation filler and resin composition of the present invention, but may be manufactured using, for example, a first resin composition comprising a first heat conductive particle and a resin material, but not comprising a second heat conductive particle, a third heat conductive particle, and fibrous aluminum nitride; a second resin composition comprising a second heat conductive particle and a resin material, but not comprising a first heat conductive particle, a third heat conductive particle, and fibrous aluminum nitride; a third resin composition comprising a third heat conductive particle and a resin material, but not comprising a first heat conductive particle, a second heat conductive particle, and fibrous aluminum nitride; and a fourth resin composition comprising fibrous aluminum nitride and a resin material, but not comprising a first heat conductive particle, a second heat conductive particle, and a third heat conductive particle.

[0201] 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, processes for which no specific temperature conditions are given were performed at room temperature, specifically 25°C. Similarly, for various measurement conditions for which no specific temperature conditions are given, the values ​​are for room temperature, specifically 25°C.

[0202] [6] Manufacturing of heat dissipation filler (Example 1)

[0203] A powder composed of aluminum nitride particles (manufactured by Toyo Aluminum Co., Ltd.) was prepared. This powder was classified to obtain a powder composed of first heat-conducting particles with a particle size of 50 μm to 300 μm (first powder). The average particle size of the first heat-conducting particles was 100 μm.

[0204] Furthermore, a powder (manufactured by Toyo Aluminum Co., Ltd.) consisting of aggregates of aluminum nitride particles was prepared. This powder was classified to obtain a powder (second powder) consisting of aggregates of second heat-conducting particles with a particle size of 5 μm or more and less than 50 μm. The average particle size of the second heat-conducting particles was 20 μm.

[0205] Furthermore, a powder (manufactured by Tokuyama Corporation) consisting of aggregates of aluminum nitride particles was prepared. This powder was classified to obtain a powder (third powder) consisting of aggregates of third thermal conductive particles with a particle size of 0.1 μm or more and less than 5 μm. The average particle size of the third thermal conductive particles was 1 μm.

[0206] Furthermore, Thermalite, manufactured by U-MAP, was prepared as fibrous aluminum nitride. The length in the long axis direction of this fibrous aluminum nitride was in the range of 1.0 μm to 5.0 cm, and the length in the short axis direction was in the range of 0.5 μm to 50.0 μm, with an aspect ratio of 2 to 200. In addition, the average length in the long axis direction of the fibrous aluminum nitride was 20 μm, the average length in the short axis direction was 2 μm, and the average aspect ratio was 10.

[0207] Then, the first powder, the second powder, the third powder, and fibrous aluminum nitride were mixed in a volume ratio of 43.5:19.5:30.0:7.0 to obtain a heat dissipation filler.

[0208] For particle size measurement, the particle shape image analysis device "PITA-04" (manufactured by Seishin Corporation) was used.

[0209] (Examples 2-7) Heat dissipation fillers were manufactured in the same manner as in Example 1, except that the mixing ratio of the first powder, the second powder, the third powder, and the fibrous aluminum nitride was changed so that the volume ratio of the first heat conductive particles, the second heat conductive particles, the third heat conductive particles, and the fibrous aluminum nitride was as shown in Table 1.

[0210] (Comparative Examples 1-11) Heat dissipation fillers were manufactured in the same manner as in Example 1, except that the mixing ratio of the first powder, the second powder, the third powder, and the fibrous aluminum nitride was changed so that the volume ratio of the first heat conductive particles, the second heat conductive particles, the third heat conductive particles, and the fibrous aluminum nitride was as shown in Table 1.

[0211] Table 1 summarizes the configuration of the heat dissipation fillers in the above-mentioned embodiments and each comparative example.

[0212]

[0213] [7] Evaluation The following evaluations were performed using the heat dissipation fillers of the above examples and each comparative example.

[0214] [7-1] Evaluation of Thermal Conductivity Resin compositions were prepared by mixing the heat dissipation fillers of the above examples and each comparative example with silicone resin as a resin material and silicone oil as a viscosity modifier, respectively. The heat dissipation filler content in each resin composition was 86.7 volume% (95.6 mass%). The thermal conductivity of the silicone resin at 25°C was 0.2 W / m·K, and the thermal conductivity of the silicone oil at 25°C was 14.0 W / m·K.

[0215] Each of the obtained resin compositions was poured into a silicone mold having a circular hollow section with a diameter of 45 mm and a thickness of 1 mm, molded, and treated at 100°C for 60 minutes to obtain resin molded bodies for thermal conductivity measurement.

[0216] For each sample obtained for thermal conductivity measurement, the thermal conductivity was determined by the hot disk method (compliant with ISO 22007-2) using a TPS-2500S manufactured by Kyoto Electronics Manufacturing Co., Ltd., and evaluated according to the following criteria.

[0217] A: Thermal conductivity is 12 W / m·K or higher. B: Thermal conductivity is 10 W / m·K or higher but less than 12 W / m·K. C: Thermal conductivity is 8 W / m·K or higher but less than 10 W / m·K. D: Thermal conductivity is 5 W / m·K or higher but less than 8 W / m·K. E: Thermal conductivity is less than 5 W / m·K.

[0218] [7-2] Evaluation of Mechanical Strength Resin compositions were prepared by mixing the heat dissipation fillers of the above examples and each comparative example with silicone resin (Momentive, TSE3431) as a resin material and silicone oil (Shin-Etsu Silicone, KF-96A-100CS) as a viscosity modifier. The heat dissipation filler content in each resin composition was 95.6% by mass, the silicone resin content was 3.1% by mass, and the silicone oil content was 1.3% by mass.

[0219] Each of the obtained resin compositions was poured into a silicone mold having a circular hollow section, molded, and treated at 100°C for 60 minutes to obtain resin molded bodies with a diameter of 45 mm and a thickness of 1.0 mm, which were used as samples for measuring mechanical strength.

[0220] Each of the obtained samples for mechanical strength measurement was subjected to tensile testing in accordance with JIS K 6251 and compression testing in accordance with JIS K 7181 using an AGX-V2 manufactured by Shimadzu Corporation, and evaluated according to the following criteria.

[0221] A: No fracture is observed in tensile and compression tests, the modulus of elasticity is relatively low, and the permanent strain after repeated compression is minor. B: No fracture is observed in tensile and compression tests, the modulus of elasticity is the same as or slightly higher than A, and the permanent strain after repeated compression is slightly higher than A. C: Localized damage occurs in tensile or compression tests, the modulus of elasticity is the same as or slightly higher than B, and the permanent strain after repeated compression is the same as or slightly higher than B. D: Fracture occurs in tensile or compression tests, the modulus of elasticity is the same as or slightly higher than C, and the permanent strain after repeated compression is the same as or slightly higher than C. E: Fracture occurs easily in tensile or compression tests, the modulus of elasticity is the same as or higher than D, and the permanent strain after repeated compression is the same as or higher than D.

[0222] [7-3] Evaluation of Hardness The heat dissipation fillers of the above examples and each comparative example were mixed with silicone resin (Momentive, TSE3431) as a resin material and silicone oil (Shin-Etsu Silicone, KF-96A-100CS) as a viscosity modifier to produce resin compositions. The heat dissipation filler content in each resin composition was 95.6% by mass, the silicone resin content was 3.1% by mass, and the silicone oil content was 1.3% by mass.

[0223] Each of the obtained resin compositions was poured into a silicone mold having a square hollow section, molded, and treated at 100°C for 60 minutes to obtain resin molded bodies with a square diameter of 50 mm and a thickness of 1.0 mm, which were used as samples for hardness measurement.

[0224] For each hardness measurement sample obtained, the hardness was measured using a Teclock GS-754G in accordance with ASTM D2240 TYPEOO, by stacking six sheets of 50 mm square and 1.0 mm thick, and evaluated according to the following criteria.

[0225] A: Shore hardness is less than 70. B: Shore hardness is 70 or more but less than 80. C: Shore hardness is 80 or more but less than 85. D: Shore hardness is 85 or more but less than 90. E: Shore hardness is 90 or more.

[0226] [7-4] Evaluation of moldability The heat dissipation fillers of the above examples and each comparative example were mixed with silicone oil (Shin-Etsu Silicone Co., Ltd., KF-96A-100CS) to produce resin compositions. The heat dissipation filler content in each resin composition was 95.6% by mass, and the silicone oil content was 4.4% by mass. The kinematic viscosity of each obtained resin composition was measured using a rheometer (Thermo Fisher Scientific, rotational viscometer) and evaluated according to the following criteria.

[0227] A: The kinematic viscosity at 25°C is less than 100,000 mPa, and no detachment of heat dissipation fillers is observed in the resulting pelletized resin composition. B: The kinematic viscosity at 25°C is 100,000 mPa or more and less than 1,000,000 mPa, and there is almost no detachment of heat dissipation fillers in the resulting pelletized resin composition. C: The kinematic viscosity at 25°C is 1,000,000 mPa or more, and there is significant detachment of heat dissipation fillers in the resulting pelletized resin composition.

[0228] These results are summarized in Table 2.

[0229]

[0230] As is clear from Table 2, the present invention yielded excellent results. In contrast, the comparative examples did not yield satisfactory results.

[0231] Furthermore, when a heat dissipation filler was manufactured in the same manner as in the above example, except that particles composed of boron nitride were used instead of particles composed of aluminum nitride as the first heat conducting particles, and evaluated in the same manner as above, good results were obtained, similar to those described above.

[0232] Furthermore, when a heat dissipation filler was manufactured in the same manner as in the above example, except that particles composed of boron nitride were used instead of particles composed of aluminum nitride as the second heat conducting particles, and evaluated in the same manner as above, good results were obtained, similar to those described above.

[0233] Furthermore, when a heat dissipation filler was manufactured in the same manner as in the above example, except that particles composed of alumina and particles composed of silica were used instead of particles composed of aluminum nitride as the third heat conducting particles, and evaluated in the same manner as above, good results were obtained, similar to those described above.

[0234] Furthermore, when resin compositions and resin molded articles were manufactured in the same manner as described above, except that the sum of the resin material content and the viscosity modifier content was varied within the range of 4.0% by mass or more and 7.0% by mass or less, and evaluated in the same manner as described above, good results were obtained, similar to those described above.

[0235] Furthermore, in the resin molded article according to the above embodiment, the thermal conductivity in the three mutually orthogonal axial directions was within the range of 4.0 W / m·K to 20 W / m·K.

[0236] Furthermore, the durability voltage values ​​of the resin molded articles according to the above embodiments, measured by a method compliant with JIS C2110-1:2016, were all within the range of 1 kV / mm to 100 kV / mm. The durability voltage was measured using a YST-243 model manufactured by Yamayo Testing Instruments Co., Ltd. For the durability voltage measurement, a metal sphere and a metal plate were used as electrodes. The upper electrode was a spherical electrode with a diameter of 20 mm ± 1 mm, and the lower electrode was a disc electrode with a diameter of 25 mm ± 1 mm, with a radius of 2.5 mm rounded at the edge. The misalignment of the central axes of the upper and lower electrodes was kept within 1 mm.

[0237] The heat dissipation filler of the present invention is a heat dissipation filler used in the manufacture of a resin molded article, and contains first heat conductive particles having a particle size of 50 μm or more and 300 μm or less, second heat conductive particles having a particle size of 5 μm or more and less than 50 μm, third heat conductive particles having a particle size of 0.1 μm or more and less than 5 μm, and fibrous aluminum nitride, wherein when the total amount of the first heat conductive particles, the second heat conductive particles, the third heat conductive particles, and the fibrous aluminum nitride is 100.0 parts by volume, the first heat conductive particles are contained in a proportion of 40.0 parts by volume or more and 70.0 parts by volume or less, the second heat conductive particles are contained in a proportion of 7.0 parts by volume or more and 30.0 parts by volume or less, the third heat conductive particles are contained in a proportion of 22.0 parts by volume or more and 45.0 parts by volume or less, and the fibrous aluminum nitride is contained in a proportion of 0.5 parts by volume or more and 13.5 parts by volume or less. Such heat dissipation fillers have excellent overall thermal conductivity and can be suitably used in the manufacture of resin molded articles that exhibit excellent thermal conductivity not only in the in-plane direction but also in the thickness direction. Therefore, the heat dissipation filler of the present invention has industrial applicability.

[0238] The resin composition of the present invention is a resin composition used in the manufacture of a resin molded article composed of a resin material, and contains the heat dissipation filler of the present invention described above. Such a resin composition has excellent overall thermal conductivity and can be suitably used in the manufacture of 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.

[0239] The resin molded article of the present invention is a resin molded article composed of a material containing a resin material, and includes the heat dissipation filler of the present invention described above. Such a resin molded article has excellent overall thermal conductivity, and for example, 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.

[0240] 1. Resin molded body 10. Heat dissipation filler 11. Fibrous aluminum nitride 12. First heat conductive particles 13. Second heat conductive particles 14. Third heat conductive particles 20. Resin material 100. High-temperature component 110. Heat dissipation component

Claims

1. A heat dissipation filler used in the manufacture of a resin molded article, comprising: first heat conductive particles having a particle size of 50 μm or more and 300 μm or less; second heat conductive particles having a particle size of 5 μm or more and less than 50 μm; third heat conductive particles having a particle size of 0.1 μm or more and less than 5 μm; and fibrous aluminum nitride, wherein when the total amount of the first heat conductive particles, the second heat conductive particles, the third heat conductive particles, and the fibrous aluminum nitride is 100.0 parts by volume, the first heat conductive particles are contained in a proportion of 40.0 parts by volume or more and 70.0 parts by volume or less; the second heat conductive particles are contained in a proportion of 7.0 parts by volume or more and 30.0 parts by volume or less; the third heat conductive particles are contained in a proportion of 22.0 parts by volume or more and 45.0 parts by volume or less; and the fibrous aluminum nitride is contained in a proportion of 0.5 parts by volume or more and 13.5 parts by volume or less.

2. The heat dissipation filler according to claim 1, wherein the first heat conducting particle comprises at least one selected from the group consisting of aluminum nitride and boron nitride.

3. The heat dissipation filler according to claim 1, wherein the second heat conducting particle comprises at least one selected from the group consisting of aluminum nitride and boron nitride.

4. The heat dissipation filler according to claim 1, wherein the third heat conducting particle comprises at least one selected from the group consisting of aluminum nitride, alumina, and silica.

5. The heat dissipation filler according to claim 1, wherein the length of the fibrous aluminum nitride in the longitudinal direction is 1.0 μm or more and 5.0 cm or less.

6. The heat dissipation filler according to claim 1, wherein the length of the fibrous aluminum nitride in the short axis direction is 0.5 μm or more and 50.0 μm or less.

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

8. A resin composition used in the manufacture of a resin molded article composed of a resin material, characterized in that it contains a heat dissipation filler according to any one of claims 1 to 7.

9. The resin composition according to claim 8, further comprising a viscosity modifier in addition to the heat dissipation filler and the resin material, wherein the sum of the content of the resin material and the content of the viscosity modifier in the resin composition is 4.0% by mass or more and 7.0% by mass or less.

10. The resin composition according to claim 9, comprising silicone oil as the viscosity modifier.

11. The resin composition according to claim 8, comprising a silicone resin as the resin material.

12. A resin molded article comprising a material containing a resin material, characterized in that it includes a heat dissipation filler according to any one of claims 1 to 7.

13. The resin molded article according to claim 12, further comprising a viscosity modifier in addition to the heat dissipation filler and the resin material, wherein the sum of the content of the resin material and the content of the viscosity modifier in the resin molded article is 4.0% by mass or more and 7.0% by mass or less.

14. The resin molded article according to claim 13, comprising silicone oil as the viscosity modifier.

15. The resin molded article according to claim 12, wherein the resin material includes a silicone resin.

16. The resin molded article according to claim 12, wherein the thermal conductivity in three mutually orthogonal axial directions is 4.0 W / m·K or more and 20 W / m·K or less in all directions.

17. The resin molded article according to claim 12, wherein the withstand voltage is 1 kV / mm or more and 100 kV / mm or less.

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