Curable Epoxy-Polyamide Adhesive for Rapid Green Strength

The patent applies preliminary action by incorporating a polyisocyanate component that reacts with hydroxyl groups in the polyamide resin to form urea linkages before final curing. This preliminary reaction creates initial crosslinks that provide green strength while the system continues to cure, effectively preparing the adhesive bond strength in advance of complete curing.

The patent uses composite materials by combining epoxy resin, polyamide resin, and polyisocyanate in a multi-component system. Each component contributes different properties: epoxy provides adhesion, polyamide provides flexibility and initial bond, and polyisocyanate provides rapid crosslinking for green strength. The synergistic combination resolves the contradiction between adhesion and curing speed.

The polyisocyanate component performs preliminary crosslinking action by reacting with hydroxyl groups to form urea linkages, creating initial structural integrity that allows the adhesive to be handled without breaking or cracking before complete curing occurs.

The patent changes the chemical parameter of the adhesive system by introducing polyisocyanate that undergoes rapid reaction with polyamide hydroxyl groups. This chemical parameter change creates a transition from a flexible, handleable state to a rigid, strength-providing state, enabling both ease of operation and high final strength.