New two-part epoxy paste structural adhesives for a thick bondline

The properties of three different adhesive pastes J-101, J-114, and EA9309.3N/A are evaluated. These adhesives are two-part thermosetting pastes which can be cured at 80-90°C and are designed for inlay or dowel bonding application, and thus are especially suitable for a bondline thickness from 0.8 to 1.6 mm. The compositions are based on CTBN-modified DGEBA and multicomponent polyamine curing agent systems. Durability and fatigue life tests are also discussed. The microstructure and fracture behavior of these adhesives is studied by scanning electron microscopy (SEM). Different toughening mechanisms are proposed to account for the toughness of these adhesives. The experimental results show that both J-101 and J-114 adhesives develop good mechanical properties when cured at 80-90°C. Furthermore, their durability performance compares favorably with, or even exceeds, that of commercially-available EA9309.3N/A adhesive.