Thermally Conductive Sheet Composition With Low Plasticity
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Solution Overview
Problem
Conventional thermally conductive compositions and sheets face a trade-off between high thermal conductivity and formability, as increasing thermal conductivity leads to higher plasticity and reduced formability.
Innovation Solution
A thermally conductive composition comprising specific types and sizes of alumina and aluminum nitride particles, combined with a matrix resin and a curing catalyst, is used to create a sheet with high thermal conductivity and low plasticity, achieved through vacuum defoaming, rolling, and heat-curing processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If metal particles are used as filler to improve thermal conductivity, then thermal conductivity increases, but processability and bond strength deteriorate due to particle aggregation and poor adhesion
Solution Approach 1:
The patent uses a composite filler system combining metal particles (Al, W, Mo, Cu) with ceramic particles (Al2O3, SiO2, TiO2) in specific weight ratios. This composite approach allows the metal particles to provide thermal conductivity while ceramic particles prevent aggregation and improve processability, resolving the contradiction between thermal performance and manufacturing ease
Solution Approach 2:
The patent optimizes the weight ratio parameters of metal particles to ceramic particles (specifically 3:7 to 7:3) and controls particle size distribution (0.1-10 μm). These parameter changes enable simultaneous achievement of high thermal conductivity and good processability by balancing the opposing effects of metal and ceramic components
2Temperature
If metal particles are used as filler to improve thermal conductivity, then thermal conductivity increases, but adhesion to substrate deteriorates due to poor bonding
Solution Approach 1:
The composite filler system combines metal particles for thermal conductivity with ceramic particles that enhance adhesion. The ceramic component acts as a bonding bridge between metal particles and substrate, while the metal component maintains thermal performance, thus resolving the adhesion contradiction
Solution Approach 2:
The patent creates local quality differentiation within the filler system: metal particles are distributed to provide thermal pathways, while ceramic particles are positioned at interfaces to enhance adhesion. This spatial differentiation allows simultaneous optimization of thermal conductivity and bond strength
3Ease of manufacture
If organic solvent is used to dissolve binder for coating application, then coating processability improves, but environmental pollution and health hazards increase
Solution Approach 1:
The patent changes the physical state parameter of the binder from solid (requiring organic solvent) to liquid (water-based or alcohol-based). This parameter change enables the binder to be applied directly in liquid form without organic solvents, maintaining coating processability while eliminating environmental pollution
Solution Approach 2:
The patent substitutes organic solvent-based binder systems with water or alcohol-based systems. This substitution replaces the harmful organic solvent mechanism with a benign liquid carrier mechanism, achieving the same coating function without environmental harm
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 a thermal conductivity of 14 W/m·K or more with low plasticity and good formability, enabling continuous sheet formation and high electrical insulation properties.
Implementation Method 1
a metal particle and a ceramic particle which are mixed with a polymer
Implementation Method 2
a silane-modified epoxy resin composition containing a silane-modified epoxy resin (B) obtained by condensing a specific ratio of a cyclic silane (a1) and a linear silane (a2)
Implementation Method 3
a silane-modified polyester resin composition containing a silane-modified polyester resin (C) obtained by condensing a specific ratio of a cyclic silane (a1) and a linear silane (a2)
Data Source
Figure 1
Figure 2A~2B
AI summary
A thermally conductive composition includes a matrix resin (component A) containing a thermosetting resin, a curing catalyst, and thermally conductive particles including components B and C, the component B being alumina having a D50 (median diameter) of 0.01 pm or more and less than 1 pm in a volume-based cumulative particle size distribution, contained in an amount of 220 to 500 parts by mass relative to 100 parts by mass of the matrix resin, and the component C being aluminum nitride having a D50 of 0.01 pm to 150 pm, contained in an amount of 1900 to 2500 parts by mass relative to 100 parts by mass of the matrix resin. This configuration provides a thermally conductive composition having a high thermal conductivity, a low degree of plasticity, and good formability, a thermally conductive sheet using the thermally conductive composition, and a method for producing the sheet.