Thermally Conductive Polyurethane Adhesive With Strength and Elongation
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Solution Overview
Problem
Existing two-component thermally conductive polyurethane adhesives lack high bonding strength and good elongation simultaneously, which is a challenge for applications requiring both properties, such as electric vehicle battery packs.
Innovation Solution
A thermally conductive, two-component polyurethane adhesive composition comprising polyisocyanate and polyol components with specific ratios of thermally conductive fillers, polyether polyols, and silane adhesion promoters, including poly(tetramethylene oxide) glycol, to achieve balanced thermal conductivity, high bond strength, and good elongation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If high levels of thermally conductive fillers are added to achieve thermal conductivity, then thermal conductivity is improved, but elongation deteriorates
Solution Approach 1:
The patent uses a composite material system combining polyether polyol, thermally conductive filler (such as aluminum oxide or aluminum nitride), and silane adhesion promoter to create a polyurethane adhesive that achieves both thermal conductivity and good elongation. The composite structure allows the filler particles to conduct heat while the polyether polyol matrix maintains flexibility and elongation properties.
Solution Approach 2:
The patent optimizes the particle size distribution of thermally conductive fillers, using a combination of fine particles (0.1-10 μm) and coarse particles (10-100 μm) to achieve both high thermal conductivity and good elongation. The specific surface area and particle size parameters are carefully controlled to balance thermal performance and mechanical flexibility.
2Temperature
If high levels of thermally conductive fillers are added to achieve thermal conductivity, then thermal conductivity is improved, but bonding strength deteriorates
Solution Approach 1:
The patent introduces silane adhesion promoter as an intermediary substance between the thermally conductive filler particles and the polyether polyol matrix. The silane coupling agent improves the interfacial bonding, allowing high filler content (40-85 wt%) to be incorporated while maintaining or even enhancing bonding strength through improved adhesion at the filler-matrix interface.
Solution Approach 2:
The patent creates a multi-phase composite material system where polyether polyol, thermally conductive filler, and silane adhesion promoter work synergistically. The composite structure ensures that thermal conductivity is enhanced by the filler while bonding strength is maintained through the flexible polyether matrix and improved interfacial adhesion.
3Strength
If polyether polyol is used to improve elongation, then elongation is improved, but thermal conductivity deteriorates
Solution Approach 1:
The patent combines polyether polyol with thermally conductive filler particles to create a composite material that overcomes the inherent low thermal conductivity of pure polyether polyol. The filler particles form thermal conduction pathways within the flexible polyether matrix, achieving both high elongation and adequate thermal conductivity (at least 1 W/m·K).
Solution Approach 2:
The patent creates local thermal conduction pathways by distributing thermally conductive filler particles throughout the polyether polyol matrix. The polyether provides good elongation in the matrix regions, while the filler particles create localized high thermal conductivity pathways, achieving overall balanced performance.
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 adhesive composition achieves thermal conductivity of at least 1 W/mK, lap shear elongation of 50% or greater, and tensile strength of more than 4 MPa, addressing the need for improved bonding and toughness in applications like electric vehicle battery packs.
Implementation Method 1
a catalyst capable of catalyzing the reaction of an isocyanate and a polyol
Implementation Method 2
40 to 85 wt% thermally conductive filler
Data Source
AI summary
Provided herein is a two-component polyurethane adhesive composition.