Pressroom Panacea?
Despite the many benefits of UV flexo technology, industry insiders are hesitant to treat it as the package printing cure-all.
by Jessica Millward, Associate Editor
THE BIG BUZZ surrounding UV flexo printing has abated slightly over the last year or two. The process' benefits —improved print resolution, less makeready time and waste, better adhesion to film substrates—have been well publicized. But with developments in water-based flexo, suppliers and converters alike have begun to wonder exactly what share of the package print pie UV flexo merits.
So what to make of UV flexo's mantra of rivaling offset? From its first appearance on the industry scene, UV flexo's advocates have positioned the process as the next big thing, ready to take on printing's big boys: offset, rotary letterpress, even short-run gravure.
"UV flexo is definitely going to continue to make headway in the label market, because converters know the advantages are real," affirms Mike Polkinghorne, VP, Propheteer International. Indeed, for narrow-web applications, he explains, the "15-20 minutes of set-up time" required for Propheteer's UV flexo presses can't be ignored.
Gallus Sales Manager Bob Yates agrees: "Growth in our UV flexo sales has outweighed growth in letterpress/screen combos." He has witnessed more converters using UV for flexible packaging, especially for coffee bags and pouches, "basically any formerly wide-web application that's gone narrow."
A tangled (wide) web
Where things get complicated is, of course, in the wide-web arena. Reports on the quantity and quality of wide-web usage vary. Several years ago, Windmöeller & Hoelscher initiated an R&D program for wide-web UV flexo, inviting all major ink and lamp suppliers to test their products on a W&H CI press. Success was limited, and tests showed high costs and severe ink and lamp limitations. Senior VP Hans Deamer finds the problems faced then still exist today. He mentions "there are still problems with opacity, especially white—getting a good, dense white down is difficult."
Deamer also cites the odor factor as an issue. Odor associated with the UV process is a result of any photoinitiators left uncured after printing. While many curing systems are touted as being complete, Deamer says he's "heard people say, depending on chemistry, you really can't cure some UV inks completely, perhaps only 96 percent to 98 percent."
Though very aware of UV flexo's capabilities in narrow-web, Deamer maintains "Systems and substrates are coming closer, but they aren't ready for wide-web CI flexo yet."
Meanwhile, BHS Printing Machinery appears to have developed a solution to the in-line wide-web UV conundrum. President Dieter Langendorf explains the construction of his company's 40&Mac253;, ten-color press for folding cartons was made possible by improvements in press configuration and UV lamps.
Langendorf predicts UV flexo will make further wide-web inroads with the evolution of inert systems now in testing phases. These systems employ an inert gas blanket around the curing lamp, reducing the amount of photoinitiators, improving speed, and reducing energy consumption.
On the continent
The trans-Atlantic gap in multitude and manner of UV flexo applications is one press manufacturers are quick to point out. As Langendorf states, "New markets for UV flexo are in folding cartons and liquid packaging. In the U.S., contrary to Europe, it is still widely used for labels." Why the global divergence? Comco International's National Sales Manager Wes Harrington says, "The only major concern with UV flexo is in direct-food contact."
As of yet, UV flexo cannot be used in direct-contact food jobs in the United States. Propheteer's Polkinghorne attests, "In Europe, UV flexo has really been taking market share away from rotary letterpress, but it's happening to a lesser extent in the States because of the food packaging issue."
This country's water-based flexo-friendly attitude may be part of the reason UV flexo's European growth appears so expansive. Nilpeter President John Little describes the historical European prejudice against water-based flexo. With the emergence of UV flexo, he notes, converters could "save face," by saying, "Oh, it's not flexo, it's UV flexo." Also, Little explains, "because the high-end market in Europe was almost exclusively UV letterpress, the switch to UV flexo was cheaper and easier."
Ultimately, improvements in water-based flexo may be UV's greatest hurdle. As Gallus' Yates states, "For general consumable packages, with paper labels, cost is critical, and you can do a good job with water-based flexo."
The UV flexo process holds its own, however, in several segments of package printing. Yates predicts, "It will continue to grow, because films are becoming more competitive in price, and are growing in demand." Little has observed a lot of UV flexo work involved in the production of the no-label look and other films.
Langendorf also notes, as a major foot forward in UV flexo's advancement, the development of digital plates and new plate systems. A key advantage, Little would concur, because "most of the major changes in the printing industry have been driven by plate changes, and if UV flexo is going to make dramatic improvements, it will be because of improvements in plates."
