Product. Description 721 waterborne curing agent is a modified amine curing agent designed for use in waterborne epoxy coatings where cost effectiveness and high performance are key requirements. 721 curing agent can be formulated to low or zero VOC. It offers good pot life, good dry speed, and good emulsion stability even at low solids. Cured coatings exhibit high gloss, a balance of hardness and flexibility, and very good adhesion to concrete. The physical and chemical