In this article, we focus on chemical labels, either for industrial (for examples paint, chemical labels) or household (under the sink) use. Typically these types of labels must appeal to the consumer, be UV light resistant, and resist chemicals, as well as mechanical stress.
At Xeikon, we did an in-depth analysis of different digital label printing technologies (dry toner and liquid toner electrophotography, UV-curable inkjet and water-based inkjet), taking into account quality basics (dot positioning and dot sizes), substrate compatibility and process reliability, as well as characteristics such as look and feel, durability and sustainability.
The results are published in a white paper which is free for download from the Xeikon website.
Based on this analysis, Xeikon generally recommends UV inkjet as the most optimal technology to produce chemical labels, because of the durability benefits this technology offers. Dry toner, however, can also come into play when a high offset quality is desired, in which case a proper protective layer is required. Let’s take a technical look at the decisive factors for choosing the right technology for a given chemical label project.
1. Look and feel
Dry toner gives a matte impression which, by applying a varnish, can give a glossy look. When fine image details (offset quality) is required, this technology is preferable. UV inkjet gives a very high gloss and tactile impression, which can appeal to certain people. The image details are not as sharp as dry toner, but this is not necessarily a requirement. In this case, the choice lies with the brand owner.
2. UV light
Lightfastness is critical for high-quality labels. It is a measure of how well a printed image resists discoloration or fading as a result of exposure to light over time. Products sitting on a store shelf or in a warehouse are often exposed to direct sunlight. The UV affects the color pigments, causing the image to lose its brightness over time. It is a natural process that can be slowed down by adding protective UV layers on top of the label (varnish or laminate). From the start, Xeikon has invested in high-quality pigments used in the dry toner and UV inkjet inks with great lightfastness scores without any additional protective finishing.
3. Chemical resistance
Cross-linked systems are generally highly resistant to chemicals, which explains the performance of UV-curable inkjet inks compared to that of toner: the resins in dry or liquid toner are mostly not cross-linked. Applying chemically-resistant lamination remedies this issue. The chemical resistance of water-based inks is due to the fact that these inks do not contain any components with an affinity for chemical solvents.
Filip Weymans is VP Global Marketing for Xeikon. For more info, visit www.Flintgrp.com/Labelexpo.