Curing agent is a kind of functional additive that promotes the transformation of polymer materials (such as epoxy resin, polyurethane, etc.) from liquid or plastic state to three-dimensional network solid structure through chemical cross-linking reaction. Its core function is to optimize the mechanical properties, heat resistance, chemical corrosion resistance and durability of materials. It is widely used in coatings, adhesives, composite materials, electronic packaging, building protection and other fields.