Waterborne UV-Curable Dispersions: Water Removal, Coalescence, Photocure and Film-Formation Coupling

A waterborne radiation-curable coating does not pass directly from liquid formulation to cured network in one step. Water must be redistributed and removed to the degree required by the system, dispersed polymer particles or domains must approach and consolidate, mobile hydrophilic species can redistribute, and reactive groups must then reach a sufficient photochemical state. These events can overlap, compete or arrest one another. A film may look dry while remaining weakly consolidated, may reach substantial chemical conversion while retaining water or morphology defects, or may develop a surface conversion state different from its interior. ER-189 treats the process as a coupled state trajectory and defines the evidence needed to qualify that trajectory without prescribing a universal flash-off or UV recipe.