Epoxy Thermal Interface Composition for Toughness and Fast Dispensing
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Solution Overview
Problem
Existing thermally conductive epoxy compositions used in thermal interface materials suffer from low fracture toughness, high viscosity leading to reduced dispensing rates, and health and safety concerns due to isocyanates in polyurethanes, which are not adequately addressed by conventional toughening agents.
Innovation Solution
A two-part curable composition comprising distinct epoxy resins with specific viscosities and amine curing agents, along with thermally conductive fillers, to form a thermally conductive interface material with improved fracture toughness, peel strength, and tensile elongation, while maintaining high dispensing rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If high particulate filler loading is used to establish satisfactory thermal conductivity, then thermal conductivity is improved, but the epoxy material becomes more embrittled and tensile elongation properties decrease
Solution Approach 1:
The patent uses a composite resin system combining a liquid epoxy resin with a liquid polyether polyol, creating a flexible polymer network that incorporates thermally conductive fillers. This composite approach allows high filler loading (70-90 wt%) while maintaining tensile elongation of at least 5%, resolving the contradiction between thermal conductivity and embrittlement.
2Temperature
If conventional epoxy resin systems are used, then thermal conductivity can be achieved with filler loading, but viscosity increases and dispensing rates decrease
Solution Approach 1:
The patent changes the chemical parameters of the resin system by using low-viscosity liquid epoxy resin (500-2000 cP) and liquid polyether polyol (1000-5000 cP), maintaining total resin viscosity below 10,000 cP. This parameter optimization allows high filler loading while keeping dispensing viscosity low, ensuring high throughput manufacturing.
3Strength
If polymeric toughening agents are added to improve fracture toughness, then fracture toughness is improved, but pre-cure viscosity increases and dispensing rates decrease
Solution Approach 1:
The patent extracts the toughening function from separate polymeric toughening agents and integrates it into the base resin system itself by using liquid polyether polyol. This eliminates the need for additional toughening additives that would increase viscosity, while still achieving tensile elongation of at least 5% and improved fracture toughness.
4Strength
If filled polyurethanes are used as alternative thermal interface materials, then fracture toughness is improved, but pre-cure viscosity is high which slows dispensing rates
Solution Approach 1:
The patent creates a composite hybrid system combining epoxy resin and polyether polyol that achieves the fracture toughness benefits of polyurethanes (through the polyol component) while maintaining the low viscosity and high dispensing rates characteristic of epoxy systems. The synergistic composite provides both mechanical flexibility and processing advantages.
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 enhanced mechanical properties such as t-peel strength, tensile elongation, and lap shear strength, with thermal conductivity of at least 1.0 W/m*K, suitable for automotive battery packs, while preserving high throughput and safety.
Implementation Method 1
The second part of the curable composition includes an amine curing agent that is effective to cure the first and second epoxy resins
Implementation Method 2
the cured thermally conductive interface material exhibits a thermal conductivity of at least 1.0 W/m*K
Data Source
AI summary
A two-part thermally conductive curable composition exhibits high dispensing rates and cures to a thermally conductive interface material with high thermal reliability, including high fracture toughness and elongation properties. The curable composition employs a combination of multi-functional and mono-functional liquid epoxy resins with low viscosity.