The use of UV cured inks in carton production has been widespread for more than 25 years with the UK’s carton producers enthusiastic adopters of the technology from the earliest days. Today UV inks are used for labels, for commercial printing and for newspapers, providing production advantages in each case. But in each of these sectors, UV plays second fiddle to conventional oxidising inks. In carton printing this state of affairs is reversed and UV is at least as popular as conventional inks.
The reasons for this position stem from the advantages that UV inks intrinsically have. There are no mineral oils and no VOCs to be absorbed into the substrate and carry taint and the risk of migration through the material. The ink is instead dried on the surface and provides a consistent printed result compared to conventional inks which are absorbed into the board.
In more recent times these advantages have been enhanced by ink formulations which eliminate any particles which may migrate through the board and so achieve the requirements that brand owners and retailers are seeking. At the same time any concerns about the health and safety issues associated with handling UV products have diminished as reputable manufacturers have developed new types of photoinitiator and understanding of the characteristics of UV chemistry have improved. “If you use the right products with the right partner and the right application procedure, there’s no reason why any converter should be concerned about working with UV inks and coatings,” says David Ward, managing director of Hubergroup UK, which has its centre for UV excellence in Switzerland.
The manufacturer continues to develop new ranges of ink, notably NewV pack and NewV poly for absorbent and non absorbent surfaces. There is also NewV pack MGA, an ultra low migration ink where the ink film comprises components that do not migrate or where there are migration capable components that these have been evaluated for contact with food stuffs.
The ink is successful at eliminating the risk of contamination even when the UV lamps are not as effective as they should be through age. The ink comes with a certificate from Huber as a guarantee that it has been produced in an GMP-compliant plant with tolerances that are tighter than those required by any law. It is this guarantee that sets Huber’s inks apart.
“We are the only ink company to offer this guarantee,” says Ward. He adds that a number of printers are now designating one press for low migration printing, where the press is effectively cordoned off to ensure that only the approved inks and consumables are used, that there is no risk of contamination being introduced and that everything meets the requirements of the auditors. To switch the ink set on a press from a standard UV ink to low migration can take several hours of deep cleaning, so there is an incentive to set aside a press specifically for low migration print work. He can only see the use of the specialist products increasing: “We are already seeing an increase. The cost and time of taking a press out for several hours is counter productive. But what will really drive this is demand from the brands that are willing to absorb the extra cost for the absolute assurance that working in this way will give them.”
The food brands want low migration UV inks. Qualvis production manager Jason Kirk says: “We are already 99% UV with Hubergroup and we are now moving more and more towards low migration because a lot of customers are asking for it because of the traceability of the product.”
Not everybody needs the extra assurance that the low migration inks provide, but all require an ink which runs without trouble on today’s fastest presses, where cutting make ready times and eliminating start up waste are prime considerations. Jon Drennan, one-time operations director at MPS in Leicester now in charge of its operations in China, explains that Hubergroup’s approach to service and technical support was key to selecting the ink supplier to work on the group’s high speed presses at the plant. “They have the relevant technical people to advise us, especially in areas where we didn’t have expertise,” he says.
“They always did what they said they would do.” This meant working on the formulation of a UV ink set so that it would run at the maximum press speed. We produce high quality technically difficult packaging for pharmaceutical companies, where we need to achieve best in industry production speeds, and the ink has delivered to our expectations. And that is all credit to their technical people for finding the solution and to their technical sales people for finding a way through the minefield.”
As a result the Huber inks are running at other facilities in the group, both in the UK and in other parts of Europe. “The attraction at the outset was Hubergroup’s almost old-fashioned approach to service which is hands on and with people to advise us,” he says.
“UV is particularly suited to just in time production,” Ward explains. “There’s no waiting to the sheet to dry before processing and inline coating and curing will eliminate a production stage if matt and gloss varnish effects are needed.”
It is also suited to printing on non-absorbent materials, whether plastics or coated materials, such as cosmetics or beverage packaging. Huber’s ink is NewV poly, a fast curing ink with a low odour formulation and high fount solution tolerance on press. The low odour feature is clearly crucial in cosmetics and points to how far UV inks have come since the days when they would be associated with a lingering and unwanted aroma.
There is some lingering suspicion about the use of UV and in many cases it is not necessary, hence the continued development of ink systems for packaging that dry through absorption and evaporation.
Ward also points out that continuing development of UV inks over the years has overcome some of the issues that early adopters faced. “Handling the UV products is not the issue it was at the beginning of UV. It does require different wash up and fount consumables. It is not difficult, just different, just as you would have a different car to drive cross country to one you would use in town,” he explains.
“We strongly believe that the use of low migration UV inks will increase especially in packaging,” he explains, “because of the security they offer and increasing awareness among brand owners and printers looking to protect themselves.”
This is not the only development in UV. In the commercial print world there is substantial interest in what Komori calls H-UV, Heidelberg LE-UV, Manroland LEC-UV and KBA HR-UV. All have a tuned UV lamp which is designed to work with a suitably formulated ink. At first the only ink suppliers were Japanese, no longer. Huber can supply the inks required. The key advantage for commercial print is a huge drop in power consumption needed compared to running conventional dryers.
The sheet is also completely dry so can pass to finishing processes without any waiting period, regardless of substrate.
UV offers a lot of advantages as demand for faster turnarounds increases. There are no compromises on quality or production speeds, and UV offers the only way to achieve the zero contamination that major brands need to assuage concerns about food safety. UV curing also dominates in label and is essential for printing on non absorbent surfaces. It truly has become the most versatile process it has long promised to be.
Huber group is at the forefront of developments in UV printing, whether the low migration inks needed for food packaging, inks for printing on non absorbent surfaces or inks for new generation UV printing which offers much to interest the commercial printer.
