“UV coating” refers to surface treatments which are cured by ultraviolet (UV) light, and are applied to a huge range of materials. This may be done to add a tough or high-shine finish, or protect the underlying material from the harmful effects of UV light in the future.
The UV coating (or ultraviolet coating) used in printing processes refers to a very glossy, shiny coating applied to the printed paper surface and cured on a special machine using ultraviolet light. These special UV coatings harden, or cure when they receive UV radiation.
UV coating makes your printed piece eye catching, and is perfect for products such as postcards, hand-out sheets, presentation folders, business cards and catalogues, or any product that can benefit from a rich, glossy and dramatic look.
UV print coatings contain photoinitiators that undergo photoreactions upon absorption of UV. The solubility and physical properties of the formulation change instantly and the coating is instantly cured. The formulations do not contain solvents or volatile organic compounds; unlike conventional substrates that have 40%. They do not dry without UV and so printing machines are easier to clean and maintain. Ultimately UV lamps are more efficient at curing than heaters are at drying.
Different photoinitiators respond to different wavelengths of UV. Most photoinitiators are activated using near UV (200-400nm range).
- UV-V (400-450 nm): deep penetration for thick layers like varnishes (e.g. furniture)
- UV-A (370-400 nm): curing heavier inks/substrates (e.g. silk screen, Japanese)
- UV-A (315-370 nm): curing bulk substrate (e.g. print press, labels and packaging)
- UV-B/UV-C: used in conjugation with UV-A to cure the very surface of substrate