tintenstrahldrucktinte with a low content of photoinitiator and method and device for hardening the same

摘要

A composition for a UV-curable inkjet ink that includes none or almost no photoinitiator, and a method of polymerizing one or more such inkjet inks having a viscosity and superficial tension suitable for inkjet printing. The UV curable inkjet ink includes 20-40% by weight of one or more monofunctional acrylates, 35-55% by weight of one or more difunctional acrylates, 5-15% by weight of one or more trifunctional acrylates, no more than approximately 5% by weight of one or more pigments; and a minute quantity or photoinitiator. One embodiment further includes 5-15% by weight of one or more highly reactive acrylates and 0.5-1.5% stabilizer. The method includes depositing the one or more inks on the substrate using one or more inkjet heads in an inkjet printer, irradiating the deposited inks with UV radiation relatively high in UVC radiation ("UVC-rich radiation"), the UVC-rich radiation produced by a first UV source, the irradiation while the substrate is moved relative to the first UV source. The method further includes depleting the region close to the substrate surface of oxygen such that the region between the first UV source and the laid out inks is relatively free of oxygen during the irradiating to increase the amount of UVC reaching the inks and to reduce the lowering caused by oxygen of the effectiveness of any photoinitiator in the ink. The inks are relatively free of photoinitiator. IMAGE