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JP-2026075462-A - Insulating, thermosoftening, and thermally conductive composition

JP2026075462AJP 2026075462 AJP2026075462 AJP 2026075462AJP-2026075462-A

Abstract

[Problem] The present invention provides a heat-softening thermal conductive composition that can sufficiently reduce thermal resistance within the operating temperature range of electronic components, exhibits excellent pump-out resistance, and provides good insulation. [Solution] A thermally softening thermally conductive composition comprising (A) a phenyl-modified silicone resin (B) thermally conductive filler comprising R 1 SiO 3/2 units and R 2 2 SiO 2/2 units, wherein the phenyl modification rate is 30 to 60 mol%, and the (B) component comprises (B-1) alumina or aluminum nitride having an average particle size of 5 to 30 μm and a sieve fraction with a mesh opening of 45 μm or more of 1% by mass and (B-2) alumina or aluminum nitride having an average particle size of 0.3 to 5 μm or (B-3) zinc oxide having an average particle size of 0.3 to 5 μm, with a mass ratio of (B-1)/(B-2) = 1.0 to 4.0 or (B-1)/(B-3) = 1.0 to 4.0 and a volume resistivity of 1.0 × 10¹⁰ Ω·cm or more. [Selection Diagram] None

Inventors

  • 伊藤 崇則
  • 西村 一晟
  • 廣中 裕也
  • 遠藤 晃洋

Assignees

  • 信越化学工業株式会社

Dates

Publication Date
20260508
Application Date
20241022

Claims (8)

  1. A thermosoftening, thermally conductive composition, (A) 100 parts by mass of a phenyl-modified silicone resin comprising R 1 SiO 3/2 units (wherein R 1 is a group selected from alkyl groups having 1 to 10 carbon atoms and phenyl groups) and R 2 2 SiO 2/2 units (wherein R 2 is a group selected from alkyl groups having 1 to 10 carbon atoms, alkenyl groups having 2 to 10 carbon atoms and phenyl groups), wherein the phenyl modification rate is 30 to 60 mol%. (B) 1,000 to 3,000 parts by mass of a thermally conductive filler, wherein the thermally conductive filler of component (B) is (B-1) Alumina or aluminum nitride having an average particle size of 5 μm or more and 30 μm or less, with a sieve fraction having a mesh opening of 45 μm or more according to JIS Z8801-1 standard of 1% by mass or less, and (B-2) Alumina or aluminum nitride having an average particle size of 0.3 μm or more and less than 5 μm. or (B-1) Alumina or aluminum nitride having an average particle size of 5 μm or more and 30 μm or less, with a sieve fraction exceeding a mesh opening of 45 μm according to JIS Z8801-1 standard of 1% by mass or less, and (B-3) Zinc oxide having an average particle size of 0.3 μm or more and 5 μm or less. Includes, A thermosoftening thermal conductive composition characterized in that the mass ratio of component (B-1) and component (B-2), or component (B-1) and component (B-3), is (B-1)/(B-2) = 1.0 to 4.0, or (B-1)/(B-3) = 1.0 to 4.0, and the volume resistivity measured according to JIS K6249 is 1.0 × 10¹⁰ Ω·cm or more.
  2. The thermosoftening, thermally conductive composition according to claim 1, characterized in that the (B) component comprises the (B-1), (B-2), and (B-3) components, and the mass ratio of the (B-1), (B-2), and (B-3) components is (B-1) / {(B-2) + (B-3)} = 1.0 to 4.0.
  3. The thermally softening, thermally conductive composition according to claim 1 or 2, characterized in that it contains 1 to 40 parts by mass of a linear aryl-modified organopolysiloxane as component (C), having one or more aryl groups with 6 to 20 carbon atoms per molecule and an aryl modification rate of 20 to 60 mol%.
  4. The thermosoftening thermal conductive composition according to claim 1 or 2, characterized in that it contains, as component (D), 10 to 60 parts by mass of an organopolysiloxane having a hydrolysis group represented by the following structural formula (1). (In the formula, R 10 is independently an aromatic hydrocarbon group having 6 to 10 carbon atoms or an alkyl group having 1 to 10 carbon atoms, and R 20 is an alkyl group having 1 to 4 carbon atoms. a is 2 or 3, and n is an integer between 2 and 60. However, it must contain 1% or more of aromatic hydrocarbon groups having 6 to 10 carbon atoms.)
  5. The thermally softening, thermally conductive composition according to claim 1 or 2, characterized in that the alumina of components (B-1) and (B-2) is spherical.
  6. The thermally softening, thermally conductive composition according to claim 1 or 2, characterized in that the aluminum nitride of components (B-1) and (B-2) is in a crushed state.
  7. The thermally softening, thermally conductive composition according to claim 1 or 2, characterized in that it contains, as component (E), 5 to 50 parts by mass of an isoparaffinic solvent with a boiling point of 80 to 360°C per 100 parts by mass of component (A).
  8. The thermosoftening thermal conductive composition according to claim 1 or 2, characterized in that the thermal resistance measured by ASTM E1430 is 10 mm² ·K/W or less.

Description

This invention relates to an insulating, thermosoftening, and thermally conductive composition. In recent years, numerous thermo-softening materials have been proposed as thermal conductive components that possess the advantages of both thermal conductive sheets and thermal conductive greases. These materials are non-flowing at room temperature but soften or melt upon heat, becoming fluid. However, materials based on organic substances (Patent Documents 1-4) have poor heat resistance, raising concerns about degradation at high temperatures when incorporated into automotive applications. While numerous similar thermo-softening materials based on silicone have been proposed to improve heat resistance (Patent Documents 1-6), these utilize a curing reaction, requiring high-temperature curing in some cases, limiting their applicability to heat-generating components. Furthermore, when arranging heat-conducting materials, applying a paste-like heat-conducting material diluted with a solvent using screen printing or similar methods is the fastest and most efficient method. However, during the drying process after application, the curing reaction proceeds from the surface of the sheet, potentially leaving solvent residue inside the sheet. Therefore, a heat-softening composition that can be applied by screen printing or other methods in paste form has been proposed (Patent Document 7). However, because it uses a wax modified from silicone, it has the disadvantage of being less flame-retardant and heat-resistant than silicone alone, and its resistance to pump-out at high temperatures was insufficient. On the other hand, silicone-based thermally conductive softening compositions that can achieve low thermal resistance through thin-film formation without using a curing reaction have also been proposed (Patent Document 8). However, these use surface treatment agents with low heat resistance, and a problem has been that the composition tends to become brittle and prone to cracking under harsh heat cycle environments. Furthermore, a silicone-based thermally conductive softening composition using copper powder with controlled particle size as the main filler has also been proposed (Patent Document 7). However, it also uses a surface treatment agent with low heat resistance and contains a large amount of conductive filler, which presents challenges in its use in fields such as power semiconductor devices where strict insulation control is required. Japanese Patent Publication No. 2021-106283International Publication No. 2016/185936International Publication No. 2015/035575Japanese Patent Publication No. 2021-80316Japanese Patent Publication No. 2016-76678Japanese Patent Publication No. 2021-147591Japanese Patent Publication No. 2017-061613Japanese Patent Publication No. 2007-59877 As described above, there was a need to develop a thermally softening, thermally conductive composition that, within the operating temperature range of electronic components, would reduce viscosity, soften, or melt, thereby adhering closely to the thermal interface, resulting in sufficiently low thermal resistance, excellent pump-out resistance, and good insulating properties. As a result of diligent research, the inventors discovered that by filling a thermo-softening phenyl-modified silicone resin with an aryl-modified surface treatment agent and a specific insulating thermal conductive filler in an appropriate ratio, a thermo-softening thermal conductive composition can be obtained that exhibits sufficient thermal resistance, excellent pump-out resistance, and good insulating properties. This led to the present invention. In other words, the present invention is A thermosoftening, thermally conductive composition, (A) 100 parts by mass of a phenyl-modified silicone resin comprising R 1 SiO 3/2 units (wherein R 1 is a group selected from alkyl groups having 1 to 10 carbon atoms and phenyl groups) and R 2 2 SiO 2/2 units (wherein R 2 is a group selected from alkyl groups having 1 to 10 carbon atoms, alkenyl groups having 2 to 10 carbon atoms and phenyl groups), wherein the phenyl modification rate is 30 to 60 mol%. (B) 1,000 to 3,000 parts by mass of a thermally conductive filler, wherein the thermally conductive filler of component (B) is (B-1) Alumina or aluminum nitride having an average particle size of 5 μm or more and 30 μm or less, with a sieve fraction having a mesh opening of 45 μm or more according to JIS Z8801-1 standards of 1% by mass or less, and (B-2) Alumina or aluminum nitride having an average particle size of 0.3 μm or more and less than 5 μm. or (B-1) Alumina or aluminum nitride having an average particle size of 5 μm or more and 30 μm or less, with a sieve fraction exceeding a mesh opening of 45 μm according to JIS Z8801-1 standard of 1% by mass or less, and (B-3) Zinc oxide having an average particle size of 0.3 μm or more and 5 μm or less. Includes, This is a thermosoftening thermal conductive composition characterized in that