Sheet Heat Dissipation Composite for Conductivity and Insulation
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Solution Overview
Problem
Existing heat dissipation materials face challenges in achieving high thermal conductivity, insulating properties, and reliability, particularly in high-temperature and high-humidity environments, due to issues with filler packability, flowability, and compatibility with silicone binders.
Innovation Solution
A sheet-like heat dissipation member composed of a silicone resin with specific siloxane units and a blend of alumina and aluminum nitride fillers, optimized in particle size and ratio, along with optional additives, to enhance thermal conductivity and adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If aluminum nitride is densely packed to achieve high thermal conductivity, then thermal conductivity is improved, but flowability of silicone binder deteriorates
Solution Approach 1:
The patent changes the particle size parameter of aluminum nitride filler, using fine particles (average diameter 0.1-10 μm) instead of coarse particles. This parameter change allows dense packing for high thermal conductivity while the fine particles maintain better flowability of the silicone binder during application
Solution Approach 2:
The patent creates local quality differentiation by using a core-shell structure where aluminum nitride particles are coated with silicone resin. The core provides high thermal conductivity while the shell maintains compatibility with the binder system, allowing dense packing without sacrificing flowability
2Temperature
If aluminum nitride is used to achieve high thermal conductivity, then thermal conductivity is improved, but water resistance deteriorates
Solution Approach 1:
The patent introduces silicone resin as an intermediary material that coats the aluminum nitride particles. This intermediary layer prevents direct contact between aluminum nitride and water, blocking the hydrolysis reaction while maintaining the high thermal conductivity of the aluminum nitride core
Solution Approach 2:
The patent converts the harmful hydrolysis reaction into a beneficial process by controlling it to occur only on the surface of aluminum nitride particles during manufacturing, forming a protective silicone-rich layer that actually prevents further water penetration and protects the bulk material
3Ease of operation
If wax or modified silicone is added to improve handling, then ease of handling is improved, but flame retardancy deteriorates
Solution Approach 1:
The patent replaces permanent wax additives with a temporary processing aid approach, using silicone resin that provides handling benefits during application but decomposes cleanly at high temperatures, leaving no harmful residues that would compromise flame retardancy
Solution Approach 2:
The patent changes the chemical composition parameter by eliminating carbon-rich wax substances and using inorganic aluminum nitride combined with silicone resin instead. This parameter change maintains processing benefits while removing the fuel source that would otherwise compromise flame retardancy
4Strength
If alumina is used to ensure compatibility with silicone, then adhesion is improved, but thermal conductivity deteriorates
Solution Approach 1:
The patent creates a composite filler system combining aluminum nitride (providing high thermal conductivity) with silicone resin coating (providing adhesion and compatibility). This composite approach achieves both high thermal conductivity and good adhesion simultaneously, resolving the trade-off between using pure alumina or pure aluminum nitride
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 solution provides a heat dissipation member with improved thermal conductivity, insulating properties, and reliability, suitable for electronic components, including automotive applications, by ensuring good adhesion and conformability.
Implementation Method 1
a thermally conductive filler having a specific particle diameter and specific surface area
Implementation Method 2
thermosoftening materials, which are in an easy-to-handle solid state at room temperature and soften or melt in response to heat generated by electronic components
Implementation Method 3
In high-humidity environments, its own hydrolysis reaction and the cracking of silicone are accelerated
Data Source
AI summary
Provided is a heat dissipation member that exhibits good adhesion to heat-generating electronic components and heat dissipation components, has good thermal conductivity and insulating properties, and is superior in reliability. A sheet-like heat dissipation member includes a composition layer formed of a thermosoftening thermally conductive composition containing: (A) 100 parts by mass of a silicone resin being solid at 25°C and having one or more types of siloxane units selected from R1SiO3/2 units, where R1 is a monovalent hydrocarbon group having 1 to 10 carbon atoms, and the SiO4/2 unit; and (B) 1,200 to 3,500 parts by mass of a thermally conductive filler composed of (B-1) and (B-2) defined as: (B-1) 120 to 1750 parts by mass of alumina having an average particle diameter of 0.1 to 70 µm; and (B-2) 600 to 2880 parts by mass of aluminum nitride having an average particle diameter of 0.1 to 70 µm and a specific surface area of 4.0 m2/g or less, wherein the mass ratio (B-1)/(B-2) = 1/9 to 1/1.