Thermally Conductive Polyurethane Adhesive With Surface-Reactive Fillers
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Solution Overview
Problem
Existing thermally conductive adhesives face a trade-off between high thermal conductivity and mechanical properties due to the need for high filler content, which compromises tensile strength, elongation, and viscosity.
Innovation Solution
A two-component polyurethane adhesive composition using surface-treated thermally conductive inorganic fillers with isocyanate-reactive groups on the surface, combined with polyols and chain extenders, to enhance mechanical properties while maintaining thermal conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If high filling grades of thermally conductive fillers are used to achieve high thermal conductivity, then thermal conductivity is improved, but mechanical properties (tensile strength, tensile elongation) and rheological properties deteriorate
Solution Approach 1:
The patent changes the surface chemistry parameters of the filler particles by introducing isocyanate-reactive groups (such as hydroxyl, carboxyl, or amino groups) on the filler surface. This surface modification enables chemical reaction with the polyurethane adhesive matrix, transforming the physical filler-polymer interface into a chemically bonded network, thereby maintaining mechanical strength at high filler loadings
Solution Approach 2:
The patent creates a composite material system where thermally conductive filler particles with isocyanate-reactive surface groups are chemically integrated into the polyurethane adhesive matrix. The resulting composite exhibits both high thermal conductivity from the filler network and maintained mechanical strength from the chemical bonding between filler and matrix
2Temperature
If high filling grades of thermally conductive fillers are used to achieve high thermal conductivity, then thermal conductivity is improved, but viscosity increases
Solution Approach 1:
The patent modifies the surface parameters of filler particles by introducing reactive functional groups that form chemical bonds with the polymer matrix. This chemical integration prevents filler aggregation and improves dispersion, thereby controlling viscosity even at high filler loadings required for high thermal conductivity
3Temperature
If high filling grades of thermally conductive fillers are used to achieve high thermal conductivity, then thermal conductivity is improved, but reliability after aging deteriorates
Solution Approach 1:
The patent performs preliminary surface treatment of filler particles by introducing isocyanate-reactive groups before adhesive formulation. This advance preparation ensures that when the adhesive cures, the filler particles are pre-configured to form strong chemical bonds with the polyurethane matrix, creating a stable structure that resists degradation during aging and maintains both thermal conductivity and mechanical strength over time
Solution Approach 2:
The patent develops a chemically bonded composite material where filler particles with isocyanate-reactive surface groups are covalently integrated into the polyurethane adhesive network. This chemical integration creates a stable, crosslinked structure that maintains reliability and performance consistency after aging, unlike physically mixed systems where filler-polymer interfaces may degrade
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 with improved mechanical properties, including tensile strength, elongation, and cohesive strength, even after aging, without significantly affecting volume resistivity.
Implementation Method 1
surface-treated thermally conductive inorganic fillers having isocyanate-reactive groups on the surface
Implementation Method 2
thermally conductive inorganic fillers
Data Source
AI summary
The present invention relates to a thermally conductive polyurethane adhesive composition having excellent mechanical properties as well as improved performance after aging and a method of manufacturing the same. Further, the present invention relates to method of manufacturing an article comprising the thermally conductive polyurethane adhesive composition and articles obtainable by the described method.