Composite resin granules and method for producing the same, and thermally conductive resin molded body using composite resin granules and method for producing thermally conductive resin molded body
Composite resin granules 5 contain a binder resin 2 and a thermally conductive filler. The thermally conductive filler includes a non-anisotropic thermally conductive filler 3 and an anisotropic thermally conductive filler 4 . The composite resin granules containing the binder resin and the thermally conductive filler are formed into a spherical shape. The particles of the anisotropic thermally conductive filler 4 are oriented in random directions. A thermally conductive rein molded body 6 of the present invention is obtained by compressing the composite resin granules 5 . Thus, the present invention provides the thermally conductive resin molded body that has relatively high thermal conductivities in the in-plane direction and the thickness direction, well-balanced directional properties of thermal conduction, and a low specific gravity, the composite resin granules suitable for the thermally conductive resin molded body, and methods for producing them.
1. A thermally conductive resin molded body comprising:
composite resin granules comprising a binder resin and a thermally conductive filler,
wherein the thermally conductive filler comprises at least an anisotropic thermally conductive filler,
a composition containing the binder resin and the thermally conductive filler is formed into granules,
particles of the anisotropic thermally conductive filler are oriented in random directions,
an average diameter of the composite resin granules is 0.01 mm or more and 5 mm or less,
the composite resin granules are molded by at least one molding process selected from the group consisting of injection molding, extrusion molding, press molding, and vacuum press molding,
the composite resin granules in the molded body are compressed and deformed so that each granule has a shape with corners, and boundaries between the composite resin granules are observable, and
a ratio (s/t) of a thermal conductivity in an in-plane direction (s) to a thermal conductivity in a thickness direction (t) of the thermally conductive resin molded body is 0.6 or more and 1.5 or less.
2. The thermally conductive resin molded body according to claim 1 , wherein a thermal conductivity in a thickness direction of the thermally conductive resin molded body is 4.0 W/m·K or more and 300 W/m·K or less.
3. The thermally conductive resin molded body according to claim 1 , wherein a ratio (s1/s2) of a thermal diffusivity in a direction (s1) to a thermal diffusivity in a direction (s2) of the thermally conductive resin molded body is 0.8 or more and 1.2 or less, where s1 represents any in-plane direction and s2 represents a direction that is along the in-plane direction and is perpendicular to the direction (s1).
4. The thermally conductive resin molded body according to claim 1 , wherein the thermally conductive filler further comprises a non-anisotropic thermally conductive filler.
5. The thermally conductive resin molded body according to claim 1 , wherein the anisotropic thermally conductive filler is at least one selected from the group consisting of hexagonal boron nitride, graphite, and graphene.
6. The thermally conductive resin molded body according to claim 1 , wherein the anisotropic thermally conductive filler has at least one shape selected from the group consisting of plate, scale, rod, needle, and fiber.
7. The thermally conductive resin molded body according to claim 4 , wherein the non-anisotropic thermally conductive filler is at least one selected from the group consisting of carbon black, aluminum oxide, aluminum nitride, silicon nitride, magnesium oxide, and silicon carbide.
8. The thermally conductive resin molded body according to claim 4 , wherein the non-anisotropic thermally conductive filler is in at least one of a spherical form and a crushed form.
9. The thermally conductive resin molded body according to claim 4 , wherein the binder resin is a thermosetting resin.