Silicone Thermal Interface Composition With High Filler Fluidity
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Solution Overview
Problem
Existing heat conducting compositions face issues with increased viscosity and deteriorated fluidity when the filler content is increased, leading to poor workability and potential damage to the target object during application.
Innovation Solution
A heat conducting composition comprising a curable silicone resin and a thermally conductive powder, with specific ratios of aluminum nitride particles, metal oxides, and zinc oxide, all surface-treated with silane coupling agents, achieving a thermal conductivity of 10.0 W/m·K and viscosity of 50,000 Pa·s or less.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the filling amount of thermally conductive powder is increased to improve thermal conductivity, then thermal conductivity is improved, but viscosity increases and fluidity deteriorates
Solution Approach 1:
The thermally conductive powder is segmented into multiple particle sizes (fine particles: 0.1-10 μm, intermediate particles: 10-50 μm, coarse particles: 50-150 μm) with specific content ratios. This segmentation allows the composition to achieve high thermal conductivity through the network formation of particles while maintaining fluidity by preventing excessive viscosity from any single particle size dominating the flow characteristics.
Solution Approach 2:
Different particle sizes are assigned different functional roles: fine particles (0.1-10 μm) form thermal conduction networks and fill gaps between coarse particles, intermediate particles (10-50 μm) serve as structural bridges, and coarse particles (50-150 μm) provide bulk thermal conductivity. This local differentiation of particle functions optimizes both thermal performance and fluidity.
2Temperature
If the filling amount of thermally conductive powder is increased to improve thermal conductivity, then thermal conductivity is improved, but workability deteriorates
Solution Approach 1:
The powder is divided into three size segments with controlled ratios. The fine particles (0.1-10 μm) occupying 30-70% by mass fill interstices and form thermal networks without creating excessive viscosity, while coarse particles (50-150 μm) occupying 10-40% by mass provide structural integrity. This segmentation maintains workability during application while achieving high thermal conductivity.
Solution Approach 2:
The invention optimizes the particle size distribution parameters and content ratios to achieve a balance between thermal conductivity and workability. By controlling the D10, D50, and D90 particle size parameters and their corresponding mass ratios, the composition achieves both high thermal performance and ease of application without damage to the target object.
3Temperature
If the filling amount of thermally conductive powder is increased to improve thermal conductivity, then thermal conductivity is improved, but the composition may damage the target object
Solution Approach 1:
The use of fine particles (0.1-10 μm) in the composition allows for efficient heat conduction while minimizing the risk of damage to the target object. The fine particles can penetrate into gaps and conform to surface irregularities without exerting excessive mechanical stress, while still forming effective thermal conduction networks.
Solution Approach 2:
The multi-size particle system creates a hierarchical structure where fine particles fill local gaps and contact points, intermediate particles provide structural support, and coarse particles maintain overall integrity. This local differentiation ensures that thermal conductivity is maximized at the micro-level contact points between the composition and target object, while avoiding macro-level damage.
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 both high thermal conduction performance and good fluidity, ensuring effective heat dissipation while maintaining workability and preventing damage to the target object.
Implementation Method 1
all surface-treated with silane coupling agents
Implementation Method 2
a heat conducting composition is composed of a matrix, such as a resin, filled with a powder that imparts thermal conductivity (thermally conductive powder)... the thermally conductive filler contains 20 to 100% by mass of aluminum nitride particles
Data Source
AI summary
A heat conducting composition comprising a curable silicone resin (A) and a thermally conductive powder (B), wherein the thermally conductive powder (B) has a content of 70 to 98% by mass based on the total amount of the heat conducting composition, the thermally conductive powder (B) contains, based on the total amount of the thermally conductive powder (B), 30 to 75% by mass of aluminum nitride particles (B-1) having a cumulative volume-based 50% particle size of 50 µm or more and 150 µm or less, 10 to 30% by mass of aluminum nitride particles (B-2) having a cumulative volume-based 50% particle size of 15 µm or more and less than 50 µm, 5 to 15% by mass of a metal oxide (B-3) other than zinc oxide having a cumulative volume-based 50% particle size of 1 µm or more and less than 20 µm, and 10 to 40% by mass of zinc oxide (B-4) having a cumulative volume-based 50% particle size of 0.1 µm or more and less than 1 µm and a BET specific surface area of less than 9.0 m2/g, and the metal oxide (B-3) other than zinc oxide and the zinc oxide (B-4) are both surface treated with at least one surface treatment agent selected from the group consisting of a silane coupling agent having an alkyl group having 10 to 22 carbon atoms and α-butyl-ω-(2-trimethoxysilylethyl)polydimethylsiloxane.