Thermally Conductive Polymer Composites Using Segmented Fillers
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Solution Overview
Problem
There is a need for polymer composites that are thermally conductive yet electrically insulative, as existing materials require high volumes of thermally conductive fillers, limiting design freedom and increasing costs due to the limited availability of suitable ceramic fillers with high thermal conductivity.
Innovation Solution
A composition comprising 35-80 vol% of a thermoplastic polymer, 5-45 vol% of a thermally insulative filler with low intrinsic thermal conductivity, and 5-15 vol% of a thermally conductive filler with high intrinsic thermal conductivity, achieving a thermal conductivity of at least 1.0 W/mK and a volume resistivity of at least 10^7 Ohm.cm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If high volume contents of thermally conductive fillers are used to achieve high thermal conductivity, then thermal conductivity is improved, but electrical insulation deteriorates and cost increases
Solution Approach 1:
The filler system is segmented into two distinct functional components: thermally conductive fillers (graphite, BN, SiC) for heat transport and thermally insulative fillers (talc, CaCO3, Mg(OH)2) for electrical insulation. This segmentation allows each filler type to perform its specialized function without compromising the other property.
Solution Approach 2:
The invention uses a composite filler system combining multiple filler types in specific volume ratios (5-45 vol% thermally insulative filler and 5-15 vol% thermally conductive filler). This composite approach creates a synergistic effect where the combination achieves both high thermal conductivity and electrical insulation, properties that individual fillers cannot achieve alone.
2Temperature
If high volume contents of thermally conductive fillers are used to achieve high thermal conductivity, then thermal conductivity is improved, but manufacturing cost increases
Solution Approach 1:
The invention replaces expensive high-performance ceramic fillers (AlN, BN with high thermal conductivity) with more cost-effective filler combinations. The use of common, inexpensive fillers like talc, CaCO3, and Mg(OH)2 as the primary thermally insulative component significantly reduces material costs while maintaining performance through the composite filler system.
Solution Approach 2:
The invention changes the filler composition parameters from traditional high-cost ceramic fillers to a optimized combination of common fillers with specific thermal and electrical properties. By adjusting filler types, sizes, and volume ratios, the formulation achieves target thermal conductivity at lower cost.
3Temperature
If limited types of ceramic fillers are used for thermally conductive composites, then thermal conductivity is maintained, but design freedom deteriorates
Solution Approach 1:
The thermally insulative filler component serves multiple functions: providing electrical insulation, contributing to thermal conductivity through the composite effect, enabling cost reduction, and allowing mechanical property optimization. This multi-functionality expands design freedom beyond single-property optimization.
Solution Approach 2:
The invention enables broad parameter optimization by selecting from diverse filler types (talc, CaCO3, Mg(OH)2, mica, glass beads) with varying properties. Designers can adjust filler combinations to optimize not only thermal and electrical properties but also mechanical strength, flow characteristics, heat stability, and cost.
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 high thermal conductivity while maintaining electrical insulation, offering a broader range of ceramic fillers and reducing costs by using less expensive thermally insulative fillers, thereby enhancing design flexibility and performance.
Implementation Method 1
thermally conductive filler with an intrinsic thermal conductivity greater than or equal to 50 W/mK wherein the thermally conductive filler comprises AlN (aluminum nitride), BN (boron nitride), MgSiN2 (magnesium silicon nitride), SiC (silicon carbide), graphite, ceramic-coated graphite, expanded graphite, graphene, a carbon fiber, a carbon nanotube (CNT), graphitized carbon black
Implementation Method 2
thermally insulative filler with an intrinsic thermal conductivity less than or equal to 10 W/mK, wherein the thermally insulative filler comprises H2Mg3(SiO3)4 (talc), CaCO3 (calcium carbonate), Mg(OH)2 (magnesium hydroxide), Mica, BaO (barium oxide), γ-AlO(OH) (boehmite), γ-AlO(OH) (diaspore), Al(OH)3 (gibbsite), BaSO4 (barium sulfate), CaSiO3 (wollastonite), ZrO2 (zirconium oxide), SiO2 (silicon oxide), a glass bead, a glass fiber, MgO·xAl2O3 (magnesium aluminate), CaMg(CO3)2 (dolomite), a clay
Data Source
AI summary
Disclosed herein are compositions comprising a. from 35 to 80 vol% of a thermoplastic polymer; b. from 5 to 45 vol% of a thermally insulative filler with an intrinsic thermal conductivity less than or equal to 10 W/mK; and c. from 5 to 15 vol% of a thermally conductive filler with an intrinsic thermal conductivity greater than or equal to 50 W/mK, wherein the composition is characterized by: i. a thermal conductivity of at least 1.0 W/mK; ii. a thermal conductivity of at least 7 times the total filler volume fraction times the thermal conductivity of the pure thermoplastic polymer; and iii. a volume resistivity of at least 107 Ohm.cm. Also disclosed are articles and methods of use therefor.