Basic Flowchart

Water-based inks remain the overall favorite, but UV-, solvent-, and soy-based inks all retain solid usage niches.

by Susan Friedman

The objective of the third annual packagePRINTING ink usage survey was simple: Take a back-to-basics look at how solvent-based, water-based, UV, and soy-based inks are faring amid package printers' growing number of substrates, specialized and combination printing needs, and environmental concerns.

packagePRINTING asked converters to indicate their ink preferences according to print process and end use. Respondents, speaking from all three major package printing sectors, offered up a blend of selections that illustrate united pockets of need with widely divided issues and applications. Looks like ink suppliers' to-do list will remain on the complex side this year.

Overall, water-based inks came up as the most common choice among respondents, with 67 percent indicating usage. This favorable return mirrored the results of packagePRINTING's first annual ink survey in 1998 (the last time water-based ink usage was measured), in which water-based topped all types, garnering 74 percent usage.

According to David Steele, manager of flexo technology at Kohl & Madden, the key improvements in water-based ink technology that keep printers' gung-ho attitude going strong are grounded in press stability and ease of use, particularly for narrow web. "Our customers are looking to minimize or eliminate the need for press-side adjustments of the inks with respect to color, printability, and viscosity," he adds.

Next up in this year's survey were UV inks, which have found their way onto 48 percent of respondents' presses. Solvent inks weren't far behind with 46 percent usage reported. Finally, soy-based inks netted a 9 percent usage level.

Water-based may have achieved the lion's share of collective usage, but did not come up as the dominant type used with every print process or every package or label end use. In fact, the survey shows that each ink type still dominates a specific niche.

For label printers, water-based inks were most popular with flexographic printing, for which 88 percent reported usage. Ed Dedman, technical marketing manager for Akzo Nobel Inks, offers one reason behind this high percentage. "The strength, or pigment concentration, of water-based flexo inks has increased greatly over the past few years, due to better resin technology and improved manufacturing methods," he comments.

For gravure label printing, solvent-based inks were the top choice, garnering 66 percent usage. Not surprisingly, UV inks were the overwhelming choice for letterpress and screen label printers—with 100 percent opting for UV in each of these processes.

Label users stick with water-based

Water-based inks really showed their buoyancy when label printers' ink preferences were broken out by end use. Printers were asked to check off every type of ink used in the printing of labels for food and beverage, medical/pharmaceutical, health/beauty, industrial/automotive, wine/spirits, electronics, and general retail applications. In every single end-use category, water-based ink captured the top spot, with usage levels in the range of 80 percent, 90 percent, and even 100 percent, in the case of wine/spirits and general retail.

An additional factor in support of water-based is bolstered rewetting capabilities—another improvement due to resin upgrades, observes Grant Wishart, director of corporate services for Graphic Sciences. Better rewetting allows for longer run times between plate wash-ups, and permits easier clean-up between and after print runs, he explains.

The simultaneous challenge, Wishart says, is achieving resistance to the real-world elements a package typically encounters. On wet or frozen packaging, for example, the ink can fail or separate from the substrate. "With water-based formulations, cure times are longer than those required for solvents, and maximum resistance is usually realized nearly 24 hours after printing," he elaborates. "But the more resistant a water-based ink is made, the harder the job is to clean, if left to dry on-press."

For flexible packaging printers, water-based ink was also No.1 for flexographic printing, with 64 percent putting it to work.

However, nearly the same number—61 percent—said they still use solvent-based inks for flexo. Solvent-based inks took a clear upper hand for gravure flexible packaging printing, with usage levels checking in at 60 percent. For this process, water-based ink lagged farther behind at 40 percent usage.

Solvent- and water-based inks continued to duke it out in the flexible packaging end-use categories. Converters indicated they most often turn to water-based technologies for fresh foods (65 percent) and medical/pharmaceutical packaging (68 percent). Solvent-based formulations dominated for dry food/snack foods (63 percent), frozen foods (86 percent), agricultural/industrial packaging (78 percent), and pet foods (73 percent).

The folding carton crowd showed the least water-based favoritism. One hundred percent of respondents who print cartons flexo are using UV inks (67 percent also use water-based technologies). On the offset side, oil-based, UV, and soy-based formulations tied, each racking up 43 percent usage.

Water-based floated a bit further out of the picture when the perspective changed to end use. Solvent-based inks were the first choice for food/beverage (50 percent) and general retail cartons (50 percent), and tied with UV as the leading ink used for electronics/game cartons (50 percent each). Soy surfaced at the top for health/beauty (50 percent) and medical/pharmaceutical cartons (60 percent), and tied with UV as the most-used ink for wine/spirit cartons (50 percent each).

Spilling sentiments

Though all three major package printing segments expressed similar purchase driver preferences, a different lead consideration emerged for each. Label printers look first at on-press handling (78 percent), while flexible package converters turn the keenest eye on safety/environmental issues (67 percent), and folding carton printers keep closest tabs on product availability (78 percent).

The topic of the single ink issue most critical to operations in the coming year also illustrated converters' broad spectrum of priorities. The most-often cited concern was on-press handling (15 percent), followed by process-specific issues (9 percent) including UV, water-based flexo, aqueous coatings, and combination printing. Cost and batch-to-batch consistency each garnered 4 percent.

To address consistency's cause, Kohl & Madden is refining systems to minimize on-press pH adjustments, viscosity, and printability. "If we can eliminate the addition of stabilizers and slow solvents press-side, we can improve long-term stability and maintain color consistency," Steele says.

Consistency came up again in an exploration of respondents' confidences and reservations about UV inks. Highest on the plus side was durability (17 percent), followed by color consistency and general color appearance (13 percent each), and handling (9 percent). The leading reservation mentioned was cost (26 percent), followed by safety/environmental issues (17 percent), and odor (8 percent).

Dedman intends to put several of these concerns to rest. "The vast majority of UV's objectionable odor comes from ozone from the lamps, which must be vented, and volatiles from paper stocks, which are ‘flashed off' due to the heat generated by the lamps," he points out. "Environmentally, UV inks are already typically less than 1 percent VOCs—how much lower can we go?"