Traditional UV-curable ink requires a reactive diluent to decrease its viscosity, which may result in increased toxicity. Therefore, water-borne UV flexographic ink coupled with water-borne UV-curable resins as binders, integrates the advantages of UV ink and water-borne ink. They have been gaining more and more attention due to excellent rheological properties and the ability to be cured at ambient temperatures by brief exposure to UV light. An electromagnetic radiation of approximately 300-450 nanometers in wavelength, is an efficient range for curing most applications.
UV cure coatings, primers and inks are used frequently in printing processes and provide unique benefits which are not attainable with the use of other technologies. These systems offer quick dry (cure), high speed, low energy and eco-friendly solutions for a number of print methods – flexographic, lithographic, offset, inkjet, screen and gravure. As an alternative to drying ovens, UV cures are based on usage of UV light to initiate a photochemical reaction that results in polymer crosslinking, which is immediately ready for further handling, as it provides an instantly dried system. The quick dry mechanism enhances printing results and makes sure that airborne impurities have almost no time to contaminate the print surface. UV cure systems used in inks for printing do not rely on solvents for reducing their viscosity. There is no evaporation of solvents, little to no VOC emissions and no loss of volume or coating thickness.
Apart from inks, primers and overprint varnishes (OPVs) can also be applied as part of UV cure systems. Primers provide a protective layer over the ink, and standardise the surface in order to accept the subsequent application of ink. UV-curing inks are widely used in packaging and printing labels with the ink-jet printing process. For applications involving indirect food contact, concerns exist about whether extremely low-viscosity UV inks are suitable with regards to migration.
More information about C&E’s eco-friendly UV-Curable Oligomer and Monomer coating products used in inks and OPVs can be found on our website. Our innovative technology results in enhanced properties such as transparency, gloss and durability.
By Ashni Arun on April 13th, 2022