Development of a Thermally Conductive Flexible Adhesive for Component Bonding

The continued miniaturization and increased performance of electronic components is a challenge for heat management especially for space applications where heat transfer is dominated by conduction. To address this challenge, a novel flexible high thermally conductive adhesive was formulated that demonstrated thermal conductivity 3-4 times of currently available commercial off the shelf adhesives. The adhesive was designed to have other favorable traits for space application including low outgassing, low modulus to reduce stress on components, low glass transition temperature, electrical insulating, and low to medium strength to facilitate rework of components. Boron nitride powders were combined with a flexible, low modulus polyurethane resin system. The impact of filler particle size, surface area, and packaging density on thermal conductivity was evaluated and optimized. In addition, the boron nitride filler was functionalized with (3-glycidyloxypropyl) Trimethoxysilane to maximize loading while maintaining favorable extrusion and shear strength properties. Surface treatment of the filler was enhanced by pretreating the filler and optimizing the treatment solution including carrier composition, silane concentration, and solution ph.