UV free-radical jet-inks are well established as the UV ink chemistry of choice for a variety of industrial printing applications. However, curing is inhibited in air and for high speed applications an inert atmosphere is required. In addition, cured films may exhibit shrinkage and have limited adhesion to media such as plastics and metals; in many cases a coating or surface treatment is needed.Cationic UV jet-inks have emerged as a new technology that can compete with free-radical in several areas. The curing mechanism is such that it is not affected by the presence of oxygen and can offer satisfactory adhesion, lower shrinkage, to plastics and metals. In contrast to the free-radical case, the inks are very sensitive to the presence of acids and bases. The former help propagate curing while the latter tend to have an inhibiting effect. Therefore, in terms of storage stability and end-use performance, such as speed of cure, it is important to balance the acidity and basicity of the inks. This paper examines some of the factors involved in stabilising cationic UV jet-inks, looking specifically at the role of acids and bases on storage and curing properties.
Alexander Grant, "Balancing Stability & Cure in Cationic UV Jet-inks" in Proc. IS&T Int'l Conf. on Digital Printing Technologies (NIP22), 2006, pp 204 - 207, https://doi.org/10.2352/ISSN.2169-4451.2006.22.1.art00052_1