Low Heat Resistance Silicone Composition for Thermal Interface Materials
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Solution Overview
Problem
Existing heat conductive silicone compositions face challenges in maintaining fluidity and workability while achieving high heat conductivity and durability under high temperature and high humidity conditions, particularly when highly filled with heat conductive fillers, leading to increased contact heat resistance and reduced reliability.
Innovation Solution
A low heat resistance silicone composition comprising specific organopolysiloxanes, α-aluminum oxide powder with a polyhedral shape, and spherical/irregular-shaped zinc oxide powder, optimized for heat conductivity, fluidity, and durability, with a defined particle size distribution and mixing ratio to ensure effective heat dissipation and insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heat conductive filler is highly filled in silicone composition to improve heat conductivity, then heat conductivity is improved, but fluidity is decreased and workability is deteriorated
Solution Approach 1:
The patent applies parameter changes by carefully controlling the particle size distribution of heat conductive fillers (specifically aluminum nitride and diamond particles with defined D10, D50, D90 values) and the viscosity of the silicone oil base to achieve optimal balance between heat conductivity and fluidity. The viscosity is controlled within 10-10,000 mm²/s at 25°C while filler content is maintained at 60-80 vol%, resolving the contradiction between high heat conductivity and good fluidity.
Solution Approach 2:
The patent uses composite materials by combining multiple types of heat conductive fillers (aluminum nitride and diamond) with different thermal conductivities and particle size distributions, and mixing them with specific silicone oil. This composite approach allows achieving high heat conductivity (2-4 W/m·K) while maintaining good fluidity and workability through synergistic effects of different particle sizes and material properties.
2Reliability
If heat conductive filler is highly filled in silicone composition to improve heat conductivity, then heat conductivity is improved, but contact heat resistance is increased
Solution Approach 1:
The patent controls the viscosity parameter of the silicone oil base within 10-10,000 mm²/s at 25°C to ensure the composition can properly wet and conform to surface unevenness, reducing contact heat resistance. Simultaneously, the particle size distribution of fillers is optimized with D50 values between 3-10 μm for aluminum nitride and 5-20 μm for diamond, allowing dense packing that reduces voids and improves thermal contact.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The composition achieves favorable heat conductivity, reduced contact heat resistance, and enhanced durability and reliability, enabling efficient heat dissipation in electronic components and devices, even under extreme conditions.
Implementation Method 1
a heat conductive grease composition in which an aluminum nitride powder which has been surface-treated with an organosilane is used... aluminum nitride has a heat conductivity of 70 to 270 W/(m·K), and diamond has a heat conductivity higher than that of the aluminum nitride, which is 900 to 2,000 W/(m·K)
Implementation Method 2
the composition has been unsatisfactory for the heat resistance at 200° C... excellent in the durability and reliability under the condition of high temperature or high temperature/high humidity
Data Source
AI summary
A low heat resistance silicone composition, including: (A) an organopolysiloxane having a specific kinematic viscosity; (B) an organopolysiloxane having a specific kinematic viscosity; (C) an α-aluminum oxide powder, α-aluminum oxide having a specific crystal structure and a particle shape with a D/H ratio in the predetermined range when a maximum particle diameter parallel to a hexagonal lattice face of the hexagonal close-packed lattice is taken as D and a particle diameter perpendicular to the hexagonal lattice face is taken as H, and the α-aluminum oxide powder having a specific average particle diameter, a specific content of coarse particles, and a specific purity; and (D) a spherical and/or irregular-shaped zinc oxide powder having a specific average particle diameter, and a specific content of coarse particles, in which the low heat resistance silicone composition has a specific heat conductivity and a specific viscosity.