Curing and Drying Technology in Printing and Packaging Substrate

The ultraviolet (UV) curing process is mainly determined by the desired application of coating. The intended end-product governs the substrate to be coated. The targeted properties like high-gloss hardness, flexibility, and resistance against chemicals or scratches have to be provided by the chemical formulations consisting of base resins, diluents, photoinitiators, and various additives. An appropriate selection of the components has to be done to enable an effective curing process; for instance, in coating containing pigments or UV light stabilizers, the special absorbance of the photoinitator has to be adjusted to a spectral region where the pigments or UV absorbers are fairly transparent. This fine tuning is necessary to match the characteristics of the lamp system with the chemistry of the coating to provide an economic curing process. Besides the physical properties of the cured material to be obtained, the economics of the coating process is the most important variable that decides the type of coating used. Thus, to calculate the total costs of a coating process, not only materials costs but the whole process design and the equipment set-up have to be considered to compare different coating processes.