A Novel Photoinitiator for U.V. Curable Digital Applications

摘要

Interest in inks and related surface coatings that can be cured by ultra-violet radiation is enlarging in the field of digital printing. The well-known and equally well-accepted advantages that U.V. curable printed inks and varnishes offer in traditional printing techniques are in most part directly applicable to non-impact printing technologies. Fast throughput from rapid "drying' and ink formulations with no volatile organic content are two examples. As a new technology or market evolves, however, it is generally accompanied by a need to develop, or at least adapt, existing raw materials and engineering designs to meet new or revised requirements. Chemical raw materials used in ink and surface coating formulations for digital printing are no exception. With this in mind, this paper introduces a new and novel photoinitiator, a chemical raw material integral to most U.V. curable inks and surface coatings, with an emphasis on digital printing applications. The chemical structure of this new photoinitiator differs from others that are commercially available and it is demonstrated how the new photoinitiator can enhance aspects such as the surface characteristics of plastics surfaces and the adhesion of U.V. curable inks to "difficult" substrates. Additionally other relevant features of this photoinitiator are explained. The photoinitiator can be described as "multifunctional" in that the molecule contains more than one reactive functional group capable of initiating free-radicals, it can also be incorporated into water-based formulations. Founded on experimental evidence, it is proposed that the new photoinitiator will be particularly suitable in surface coatings used to create digitally printed flexible packaging. But due to its versatility, other, more diverse applications are presented.