Design for the Environment
U.S. EPA’s comprehensive study on solvent-based, water-based and UV inks on wide web flexo applications offers insights.
By David Savastano, Editor
The U.S. flexographic industry is an approximately $50 billion segment, and has been growing at a nearly 6 percent rate for years. The growth of flexo caught the attention of the U.S. Environmental Protection Agency (EPA), which wanted to do a comprehensive study on the environmental impact, cost and performance of solvent-based, water-based and UV ink systems for the flexo process as part of its continuing effort in developing CTSAs (Cleaner Technology Substitute Assessments) for the graphic arts industry.
In order to conduct the study, the EPA focused on printing on wide web film. The result can be found in the Design for the Environment (DfE) study, published recently, titled “An Evaluation of Flexographic Inks on Wide-Web Film.”
More than 50 trade organizations, ink companies, printers and related industries donated their time and products for the study, which took more than six years.
“The pressing issue was printing on film with water, solvent and UV inks, and the study offered a look at issues such as air emissions, hazardous waste, handling and how end products look,” said Doreen Monteleone, director of membership and environmental services with the Flexographic Technical Association (FTA).
While some of the results can be debated, it was a massive undertaking that ultimately provides benefits for printers and ink companies.
Perhaps the biggest surprise from the study was that none of the three types of ink was found to be superior to each other. “No ink system was superior across performance, environmental, health and cost criteria, although each system had advantages,” the study reported in its findings. “The choice of formulations within an ink system is just as important as the choice of ink system itself.”
Breaking the comparisons down, the study concluded that water-based inks outperformed solvent inks on LDPE and PE/EVA, while solvent did better on the adhesive lamination test. UV did worst on the gloss, which is contradictory to typical performance, although UV-cured inks displayed good trapping and resistance to blocking. In terms of average cost, factoring in materials, labor, energy and capital, water-based systems were the least expensive.
“If you looked at it purely from a performance standpoint, the fact that one ink system did not outshine the other would have come as no surprise to the inkies,” said George Fuchs, environmental affairs manager for National Association of Printing Ink manufacturers (NAPIM). “The comprehensive evaluation matrix that the DfE project applied to the different ink systems clearly indicated that each system has its pluses and minuses and that on balance it provided a fair and accurate assessment of each system’s capabilities, both positive and negative.”
The results for UV were considered somewhat unusual, which is understandable considering that UV had not made much of an impact in the wide web film market at the time the study was being conducted.
“It’s a snapshot in time. It took a long time and a lot of work, and by the time we got to the end of the study, UV ink had advanced further,” Ms. Monteleone said.
“There were no surprises for me in terms of the results for solvent- and water-based inks,” said Richard Grandke, industry manager, printing and packaging at Johnson Polymer. “However, I think UV may have been too premature to put in that study, because there wasn’t a commercialized use of UV on wide web film at the time of the study. It’s really new and emerging in that segment.”
For Paul Lodewyck, Flint Ink’s vice president, total printing systems, packaging division, the conclusion that none of the ink systems were found to be superior to the other is not borne out by the market, which is overwhelmingly solvent-based in wide web film.
“If performance, cost, and EH&S criteria were perceived by the industry as equivalent, you would expect to see similar consumption of solvent, water, and UV in flexo printing,” Mr. Lodewyck said. “In fact, you don’t see that, and I don’t see trends to have them equalize soon. This suggests that the market doesn’t agree with this interpretation.
“I think there are two things to take into account,” Mr. Lodewyck added. “First there’s the issue of representative components. Individual components were taken and used as representative of an industry. Looking back, some components may have been more representative than others. Secondly, there is the issue of weight factors. For cost, effective weighting is automatically built in since there is a common measure that everyone accepts – dollars. Weighting is also an issue on performance.Some performance issues are dealbreakers while others are not as critical. The market tells us that there are specific applications where one technology on balance works better than others.”
Overall energy usage was also studied in the analysis. Solvent inks were found to consume the most energy due to the need for oxidizing hazardous compounds, while water inks used the least. However, energy costs were highest for UV-cured inks.
“I appreciated the insight around energy consumption/environmental impact when you include the whole delivery chain,” Mr. Lodewyck said. “In the past, we all tried to attack the part that was in our sphere of control, and we see that it didn’t necessarily make a difference in the big picture. It underscores the need for a systems approach to the issue.”
As for safety concerns, the study concluded that “None of the ink systems as predicted to pose clear concerns for health risks to people in surrounding communities. However, all ink systems contained chemicals of clean concern for health risks to flexo pressroom and prep-room workers, as well as safety hazards.” UV inks were found to have virtually no VOCs (volatile organic compounds).
Among the recommendation on how to best cope with those ingredients the study suggested using protective gear such as gloves or respirators if needed, developing safety policies and providing proper ventilation.
On the health side, participants felt the study provided good advice. “I think that EPA did an excellent job on the safety and health recommendations in the DfE project,” Mr. Fuchs said. “Both inkies and printers can learn a lot by carefully reviewing the recommendations in this document.”
“In EH&S, it’s hard to weight various thresholds,” Mr. Lodewyck said. “We’re comparing apples and oranges in the various measures. An ideal common denominator would measure total lost time, career length, longevity or some other overall impact, which is obviously not practical in a study like this. In addition, if I walk into a flexo press room today, it is generally a far cry from 20 years ago, not just in printing technology. Years of real leadership, primarily by government environmental organizations, have in fact changed the practices in industry. Many hazards have been functionally mitigated as a norm.
“The interaction of us humans, our work environment, and the materials we deal with is incredibly complex,” Mr. Lodewyck added. “My personal guideline is to have a healthy respect for all the things we deal with, because you never know what we will learn about them tomorrow.”
Was DfE Worthwhile
All of the participants said they felt the study offers benefits to printers and the ink industry alike.
“The study was absolutely worthwhile – specifically and generally,” Mr. Fuchs said. “Not only does it provide a comprehensive assessment of flexo printing using solvent, water and energy curable but it has also developed an excellent template for future evaluations.
“From my perspective, the DfE study will be of greatest benefit to ink companies as they evaluate components for current and future ink systems,” he added. “EPA did a really excellent job in the area of toxicity evaluations of materials that are typically used in the various flexographic ink systems.”
“In my view there really were not any individual/discrete ‘key findings,’” Mr. Fuchs said. “More important was EPA’s comprehensive, ‘holistic’ and unbiased approach to the evaluation and assessment of an industry sector like flexo printing with an eye towards minimizing environmental and human health impact. To my knowledge this approach has never before been attempted by EPA and I think they need to be recognized and applauded for their efforts.”
“It was a big project to undertake,” Mr. Grandke said. “I think it was worthwhile, because it opened some people’s eyes. For printers and converters, it allowed them to look at what their options are when they are making decisions.”
“It was an extremely good effort,” said Ms. Monteleone. “The study had the involvement of quite a number of flexo printers, ink and substrate suppliers, and printers and ink manufacturers will benefit. Ink companies can take a harder look at their products, and printers can better question their ink suppliers.”
“Overall, the study provides a lot of excellent information, but just like everything else in life, the devil is in the detail,” Mr. Lodewyck said. “Overall, I found the thoroughness of the analysis as a process to be very enlightening. As individual suppliers, we don’t have access to the kind of overall expertise and therefore can’t think about issues like what was done in the study. It should lead us to examine some of the basic intuitive assumptions that flavor our everyday thinking.
“I think the daily workers in ink and converting will get the greatest benefit over time,” Mr. Lodewyck continued. “Ink companies will follow the technical and economic demands of the marketplace. It is unlikely any ink company will be at a relative advantage or disadvantage in this regard. However, this study helps us better understand and communicate the risks, and we will better contribute to a better working environment for all.”
If the DfE study achieves that, all of the hard work done on the study will be more than worthwhile.