UV gravure inks
Gravure printing is a very good printing method, gravure printing rich and clear layers, thick ink layer, uniform ink color, high saturation, bright and vivid color, can truly reproduce the original effect. But the traditional gravure printing technology ink solid content is low, the solvent volatilization is large, so that the printed dot is not full, dot reduction effect is not as good as offset printing; at the same time due to the volatilization of solvents, the concentration of ink changes, affecting the consistency of the color of the printed matter. After the use of UV printing, these problems have been completely resolved, and the dot reduction effect is higher than offset printing.
Volatile organic compounds (VOC) emissions from ink cause air pollution, gravure printing is the most serious. Currently plagued by the world’s printing industry is how to completely solve the problem of gravure printing organic volatile organic compounds (VOC) emissions.
Countries around the world are developing and using water-based gravure printing ink, water-based gravure printing ink printing to a certain extent can reduce organic volatile organic compounds (VOC) emissions. However, the printing effect of water-based gravure printing ink, the printing of the sense of hierarchy, ink layer thickness, ink color uniformity, clarity, saturation, color vividness, etc. are not as good as solvent-based ink. As the printing of water-based inks need to dry at high temperature conditions, so in food, daily chemical and pharmaceutical products such as plastic flexible packaging printing there are certain difficulties.
Gravure printing and other printing methods is different from its printing plate after corrosion or engraving, the formation of many below the surface of the printing plate with different volume of inking holes, these inking holes form the gravure printing plate graphics. In the printing process, the intaglio roller surface immersed in the ink tank, the surface of the inking holes filled with ink, by the scraper will be excess ink scraping off, only in the inking holes filled with ink, intaglio roller continues to rotate, inked intaglio roller with the substrate and the impression roller in contact with each other, under the action of the pressure, inking holes in the ink in contact with the substrate, due to substrate adsorbent, the ink is transferred to the substrate. As the gravure roller continues to rotate, the inking plate and the substrate separation, then part of the ink transferred to the substrate, part of the ink flow back to the inking hole, complete the printing process.
In the printing process, gravure printing process is simpler than offset printing, there is no offset ink and water balance, and is directly printed, its color reproduction and color consistency is better, and the scrap rate is low, the substrate waste is less, especially the print resistance is much higher than offset printing, the number of prints generally up to more than 500,000 prints, very suitable for high-grade tobacco and wine packaging printing. Gravure printing is the most important feature of the ink layer of the print is thicker, generally in the 9 ~ 20μm, almost twice as thick as the ink layer of the flexographic printing, the print has a strong sense of three-dimensionality, clear levels, color and lustre is bright and full.
How formulators usually evaluate this photoinitiator topic
When technical buyers or formulators screen photoinitiators, the most useful decision frame is usually cure quality plus application fit: which package cures reliably, keeps appearance acceptable, and still works under the lamp, film thickness, and substrate conditions of the actual process.
- Match the package to the lamp first: mercury lamps, UV LEDs, and visible-light systems can rank the same photoinitiators very differently.
- Check depth cure and surface cure separately: a film that feels dry on top can still be weak underneath.
- Balance yellowing with reactivity: the strongest deep-cure route is not always the best commercial choice if color or migration risk becomes unacceptable.
- Use the final formula as the benchmark: pigment load, monomer package, and film thickness can all change the apparent ranking of the same initiator.
Recommended product references
- CHLUMINIT TPO-L: A strong low-yellowing reference for LED-oriented UV systems.
- CHLUMINIT 819: Useful when a formulation needs stronger absorption and deeper cure support.
- CHLUMINIT 184: A classic free-radical benchmark for fast surface cure in many UV systems.
- CHLUMINIT 1173: A practical comparison point for classic short-wave UV initiation.
FAQ for buyers and formulators
Why are blended photoinitiator packages so common?
Because one product may control yellowing or lamp fit well while another improves cure depth or line-speed performance, so the full package is often stronger than any single grade.
Should incomplete cure always be solved by adding more initiator?
Not automatically. The real limitation may be the lamp, film thickness, pigment shading, or the rest of the reactive system rather than simple under-dosage.
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Quick answer: For practical formulation work, photoinitiator screening starts with the light source and film build, then checks yellowing, adhesion, and cure completeness under real production conditions.
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