Fumed Aluminium Oxide Anti-Settling in Polymer Composites
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Solution Overview
Problem
Thermally conductive polymer compositions face issues with sedimentation of fillers due to density differences, leading to uneven thermal conduction and reduced efficiency, and existing anti-settling substances impair processability and thermal conductivity.
Innovation Solution
Incorporating fumed aluminium oxide with a BET surface area of 15 m2/g to 200 m2/g in a proportion of less than 5% by weight into thermally conductive polymer compositions to reduce or prevent sedimentation without affecting thermal conductivity or processability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If thermally conductive fillers are added to increase thermal conductivity, then thermal conductivity is improved, but sedimentation occurs due to density differences
Solution Approach 1:
Fumed aluminium oxide serves as an intermediary substance with intermediate density between the dense thermally conductive filler and the less dense prepolymer. This intermediary material creates a density gradient that reduces the density difference driving force for sedimentation, allowing thermally conductive fillers to remain suspended while maintaining high thermal conductivity of the overall composition.
Solution Approach 2:
The invention changes the density parameter of the composition by introducing fumed aluminium oxide with specific density characteristics. This parameter change modifies the sedimentation behavior by reducing the effective density difference between filler and matrix, thereby preventing unwanted sedimentation while preserving thermal conductivity enhancement.
2Stability of the object's composition
If anti-settling substances are added to prevent sedimentation, then sedimentation is reduced, but thermal conductivity and processability are impaired
Solution Approach 1:
The fumed aluminium oxide is specifically selected with particular density and particle size characteristics that are locally optimized for this dual function. Unlike generic anti-settling agents, this specific material provides sedimentation resistance while maintaining thermal conductivity because its properties are locally tailored to match the requirements of both functions simultaneously.
Solution Approach 2:
Fumed aluminium oxide performs multiple functions: it acts as an anti-settling agent to prevent sedimentation of thermally conductive fillers, while simultaneously maintaining or even contributing to the thermal conductivity of the composition. This multi-functionality eliminates the need to choose between sedimentation resistance and thermal conductivity.
3Stability of the object's composition
If anti-settling substances are added to prevent sedimentation, then sedimentation is reduced, but viscosity increases and meterability is impaired
Solution Approach 1:
The fumed aluminium oxide has specific particle size and surface area parameters that are optimized to provide anti-settling effects without excessive viscosity increase. By controlling these parameters, the material achieves sedimentation resistance while maintaining acceptable meterability and processability of the composition.
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 use of fumed aluminium oxide effectively prevents sedimentation while maintaining thermal conductivity and processability, ensuring uniform heat dissipation and extended component lifespan.
Implementation Method 1
particles of fumed aluminium oxide having a BET surface area of 15 m2/g to 200 m2/g... for reducing the sedimentation of thermally conductive particles in polymer compositions
Data Source
AI summary
The present invention relates to a composition comprising at least one prepolymer, thermally conductive particles and particles of fumed aluminium oxide having a BET surface area of 15 m2/g to 200 m2/g. The invention further relates to a method for producing a heat-conducting composition comprising the step of adding fumed aluminium oxide having said BET surface area to the composition. The present invention also relates to the use of fumed aluminium oxide having a BET surface area of 15 m2/g to 200 m2/g to reduce sedimentation of thermally conductive particles in polymer compositions.