Thermally Conductive Silicone Grease Composition for Heat Dissipation
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Solution Overview
Problem
Existing heat conductive silicone grease compositions fail to provide satisfactory electrical insulation and heat conduction, especially when heavily loaded with fillers, leading to reduced durability and reliability under hot or hot humid conditions, and are inadequate for advanced IC devices like CPUs.
Innovation Solution
A heat conductive silicone grease composition comprising an organopolysiloxane, a specific spherical aluminum oxide powder, and a spherical/irregular zinc oxide powder, blended in a specific ratio, with surface treatment using an alkoxysilane, ensuring high thermal conductivity, smooth flowability, and durability under extreme conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If heat conductive filler is heavily loaded to improve thermal conductivity, then thermal conductivity is improved, but flowability deteriorates
Solution Approach 1:
The patent uses a polysiloxane base fluid with specifically controlled viscosity parameters (20-1000 cSt at 25°C) to maintain flowability while heavily loaded with heat conductive filler (60-80 wt%). The base fluid's viscosity parameter is optimized to balance thermal conductivity enhancement with adequate flow properties for application.
Solution Approach 2:
The patent creates a composite grease composition combining polysiloxane base fluid with multiple heat conductive fillers (aluminum oxide, zinc oxide, aluminum nitride) in specific ratios. This composite structure achieves high thermal conductivity (2.0-5.0 W/m·K) while maintaining workability through the synergistic combination of materials with different properties.
2Temperature
If heat conductive filler is heavily loaded to improve thermal conductivity, then thermal conductivity is improved, but electrical insulation deteriorates
Solution Approach 1:
The patent employs a multi-component filler system where aluminum oxide (insulating) and zinc oxide (insulating) form the bulk structure, while aluminum nitride (highly conductive but electrically conductive) is limited to 5-20 wt%. This local quality differentiation ensures high thermal conductivity pathways are formed without compromising overall electrical insulation properties.
Solution Approach 2:
The patent controls the volume fraction of aluminum nitride powder (highly thermally conductive but electrically conductive) to maintain electrical insulation while achieving high thermal conductivity. The specific parameter control of filler composition and distribution ensures thermal pathways are established without creating electrical conduction paths.
3Ease of operation
If conventional silicone grease is used to maintain flowability, then flowability is maintained, but durability under hot humid conditions deteriorates
Solution Approach 1:
The patent incorporates hydrophobic modified polysiloxane and surface-treated fillers in advance to prevent water absorption and degradation before exposure to hot humid conditions. The base fluid contains additives that pre-establish water repellency and thermal stability, ensuring durability is maintained from the outset of service.
Solution Approach 2:
The patent creates a composite grease formulation combining hydrophobic modified polysiloxane base fluid with surface-treated heat conductive fillers. This composite structure provides both flowability and enhanced durability under hot humid conditions, resisting water washout and thermal degradation that plague conventional silicone greases.
4Temperature
If filler particle size is reduced to improve heat conduction, then heat conduction is improved, but manufacturing complexity increases
Solution Approach 1:
The patent uses a mixed particle size distribution of fillers rather than uniformly fine particles. Coarser particles (providing structural framework) are combined with finer particles (filling voids and enhancing thermal pathways). This partial refinement approach achieves improved heat conduction without the excessive manufacturing complexity of producing and handling ultra-fine uniform particles.
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 efficient heat dissipation, maintains flowability, and ensures reliability and durability, effectively transferring heat from heat-generating electronic parts to heat-dissipating parts, even under hot or hot humid conditions, enhancing the stability and lifetime of electronic equipment.
Implementation Method 1
surface treatment using an alkoxysilane
Implementation Method 2
efficiently transferring heat from heat-generating electronic parts to heat-dissipating parts
Data Source
AI summary
Provided is a thermally conductive silicone grease composition that comprises: (A) an organopolysiloxane having a specific kinematic viscosity; (B) an organopolysiloxane having a specific kinematic viscosity; (C) a spherical aluminum oxide powder which has a specific average sphericity, a specific number of surface hydroxyl groups, and a specific average particle size, and for which the proportion of coarse particles in a laser diffraction type particle size distribution of 25 to 45 µm is within a specific range; and (D) a spherical and/or amorphous zinc oxide powder which has a specific average particle size, and for which the proportion of coarse particles in a laser diffraction type particle size distribution of 25 to 45 µm is within a specific range. The composition has a thermal conductivity measured by the hot disk method conforming to ISO 22007-2 of 2 W/m·K or more and less than 5.5 W/m·K, has a coefficient of viscosity measured by a spiral viscometer at a rotation frequency of 10 rpm of 5 to 800 Pa·s, has insulation properties and high thermal conductivity, and has excellent flowability, workability, and heat dissipation properties.