SHINE H100" COAT" PU HARDENER hardener, also known as a curing agent or activator, is a component used in conjunction with polyurethane coatings, adhesives, or resins. It reacts chemically with the polyurethane resin to initiate the curing process, transforming the liquid mixture into a solid, durable material. The hardener influences the final properties of the polyurethane, such as hardness, flexibility, chemical resistance, and drying time. Different types of hardeners can be selected to tailor these properties to specific application requirements.