Application of the Freeze-Dry Method to Water-Sensitive Epoxy Adhesives for Reliable Bonding Joints

Moisture absorption during the uncured stage often leads to a reduction in the energy release rate after curing epoxy adhesives. Therefore, an effective method for removing moisture from adhesives is highly desired. In this study, we explored the application of freeze-drying—commonly used in food processing—to uncured epoxy adhesives. Film-type epoxy adhesives, AF555 (3M) and FM309 (Solvay), were subjected to freeze-drying and evaluated using the Double Cantilever Beam (DCB) method. The results showed an increase in energy release rate and a decrease in data dispersion, indicating improved reliability of the bonded joints.