Curability, Workability and Stability Investigation on a Novel Pure Liquid One Component Thermal Curable Epoxy Adhesive

A novel one component thermal curable epoxy adhesive composed of all liquid reactive ingredients was developed recently. Its thermal cure behavior was measured and analyzed with differential scanning calorimetry isothermal method. Workability and pot life at room temperature as well as storage stability and shelf life under chilled, frozen conditions were measured and analyzed by monitoring its viscosity change during the storage period. The measurement results confirmed that the novel one component epoxy adhesive can cure well at relatively low temperature and its pot life is much longer than conventional two component epoxy adhesives with similar curability and adhesion performance. The novel one component epoxy adhesive was also confirmed to be very stable and its shelf life can be several years long under suitable frozen storage. Based on cure behavior measurement results, cure kinetics of the novel one component epoxy adhesive was investigated. Arrhenius equation obtained from kinetics plot curve was applied to predict pot life and shelf life and it was found that the predicted pot life and shelf life correlate very well with actual measured results. Crystallization temperature of the novel epoxy adhesive was also measured and found to have close relationship with storage stability. This study verified that differential scanning calorimetry isothermal method can be used to predict shelf life of one component epoxy products. In addition, crystallization temperature measurement can be utilized for better stable epoxy adhesive development and suitable storage temperature determination.