Curable thermally conductive grease, heat dissipation structure, and method for producing heat dissipation structure

A heat dissipation structure for an electronic device, comprising a heat-generating body, heat-dissipating body configured to dissipate heat generated from the heat-generating body, and a curable thermally conductive grease that is provided between the heat-generating body and the heat-dissipating body to facilitate heat transfer from the heat-generating body to the heat-dissipating body,

• wherein the curable thermally conductive grease that fills a gap between the heat-generating body and the heat-dissipating body has a thickness of more than 1 mm and 10 mm or less, and
• the heat-generating body or the heat-dissipating body is subjected to a compressive stress of 1.0 N/cm2 or less from the curable thermally conductive grease, and
• the curable thermally conductive grease comprises;
• a first agent including
• an addition reaction-curable liquid polymer,
• a first thermally conductive filler (A) having aluminum hydroxide and an average particle diameter of 0.3 μm to 8 μm, and
• a first thermally conductive filler (B) having an average particle diameter of 70 μm to 100 μm,
• the ratio by volume of the first thermally conductive filler (A) to the first thermally conductive filler (B), i.e., (A)/(B), being 0.65 to 3.02;
• a second agent including
• a curing agent of an addition reaction-curable liquid polymer, which is different from the addition reaction-curable liquid polymer of the first agent,
• a second thermally conductive filler (A) having aluminum hydroxide and an average particle diameter of 0.3 μm to 8 μm, and
• a second thermally conductive filler (B) having an average particle diameter of 70 μm to 100 μm,
• the ratio by volume of the second thermally conductive filler (A) to the second thermally conductive filler (B), i.e., (A)/(B), being 0.65 to 3.02, and the curable thermally conductive grease having a viscosity of 700 Pa·s to 2070 Pa·s, at a rotation speed of 1 rpm and a measured temperature of 23° C.,
• wherein after the curable thermally conductive grease is applied to the heat-generating body or the heat-dissipating body to a thickness of 5 mm, the curable thermally conductive grease has slump resistance in which the curable thermally conductive grease does not flow down when the heat-generating body or the heat-dissipating body is vertically arranged,
• wherein a solid content included in the curable thermally conductive grease is only
• the first thermally conductive filler (A),
• the first thermally conductive filler (B),
• the second thermally conductive filler (A) and
• the second thermally conductive filler (B)
• as the solid content other than that derived from the addition reaction-curable liquid polymer and the curing agent of the reaction-curable liquid polymer, and
• wherein the first thermally conductive filler (A), the first thermally conductive filler (B), the second thermally conductive filler (A), and the second thermally conductive filler (B) are at least any one of following material selected from the group consisting of
• powders of metals,
• at least any one of powders of metal oxides selected from the group consisting of aluminum oxide, magnesium oxide, and zinc oxide,
• powders of metal nitrides,
• powders of metal carbides,
• powders of metal hydroxides, and
• carbon fibers.

A method for producing a heat dissipation structure for an electronic device, the heat dissipation structure including a heat-generating body, a heat-dissipating body configured to dissipate heat generated from the heat-generating body, and a curable thermally conductive grease that is provided between the heat-generating body and the heat-dissipating body to facilitate heat transfer from the heat-generating body to the heat-dissipating body, the method comprising, in sequence:

• applying the curable thermally conductive grease to the heat-generating body or the heat-dissipating body in such a manner that the curable thermally conductive grease provided between the heat-generating body and the heat-dissipating body has a set thickness of more than 1 mm and 10 mm or less and that the curable thermally conductive grease before curing has a larger thickness than the set thickness, wherein the curable thermally conductive grease comprises
• a first agent including
• an addition reaction-curable liquid polymer,
• a first thermally conductive filler (A) having aluminum hydroxide and an average particle diameter of 0.3 μm to 8 μm, and
• a first thermally conductive filler (B) having an average particle diameter of 70 μm to 100 μm,
• the ratio by volume of the first thermally conductive filler (A) to the first thermally conductive filler (B), i.e., (A)/(B), being 0.65 to 3.02;
• a second agent including
• a curing agent of an addition reaction-curable liquid polymer, which is different from the addition reaction-curable liquid polymer of the first agent,
• a second thermally conductive filler (A) having aluminum hydroxide and an average particle diameter of 0.3 μm to 8 μm, and
• a second thermally conductive filler (B) having an average particle diameter of 70 μm to 100 μm,
• the ratio by volume of the second thermally conductive filler (A) to the second thermally conductive filler (B), i.e., (A)/(B), being 0.65 to 3.02, and the curable thermally conductive grease having a viscosity of 700 Pa·s to 2070 Pa·s, at a rotation speed of 1 rpm and a measured temperature of 23° C.,
• and after the curable thermally conductive grease is applied to the heat-generating body or the heat-dissipating body to a thickness of 5 mm, the curable thermally conductive grease has slump resistance in which the curable thermally conductive grease does not flow down when the heat-generating body or the heat-dissipating body is vertically arranged;
• pressing the applied curable thermally conductive grease to the set thickness to assemble the heat-generating body and the heat-dissipating body;
• curing the curable thermally conductive grease, and
• wherein a solid content included in the curable thermally conductive grease is only
• the first thermally conductive filler (A),
• the first thermally conductive filler (B),
• the second thermally conductive filler (A) and
• the second thermally conductive filler (B)
• as the solid content other than that derived from the addition reaction-curable liquid polymer and the curing agent of the reaction-curable liquid polymer, and
• wherein the first thermally conductive filler (A), the first thermally conductive filler (B), the second thermally conductive filler (A), and the second thermally conductive filler (B) are at least any one of following material selected from the group consisting of
• powders of metals,
• at least any one of powders of metal oxides selected from the group consisting of aluminum oxide, magnesium oxide, and zinc oxide,
• powders of metal nitrides,
• powders of metal carbides,
• powders of metal hydroxides, and
• carbon fibers.