Digital Magazine

EPA and printers join forces to evaluate inks.

Determined to secure systematic, comparative data on inks, the flexo industry and the Environmental Protection Agency have launched the Design for the Environment Flexography Project.

Film converters around the country are actively trying to determine what sort of ink technology - solvent-based, water-based, or ultraviolet-cured - can best meet their needs for wide web flexography. The ink that wins favor must satisfy high industry standards not only in cost and product quality but also in environmental and health safety.

Yet for all the hard work done to date, information comparing the three ink technologies in a complete and systematic way is not always easy to find. In response to this problem, representatives from the flexography industry have joined forces with the US Environmental Protection Agency to form the Design for the Environment (DfE) Flexography Project.

Together, the partners of DfE will systematically evaluate solvent-based, water-based, and UV-cured inks. Samples of each ink technology will be run to specific parameters in both field demonstrations and in a laboratory setting. The resulting printed images will then be subjected to a battery of tests designed to answer questions about each ink's cost, performance, and environmental and health attributes.

Most importantly, the information gathered will then be compiled and distributed to the converting industry. With this information in hand, converters can make more efficient, educated choices when answering the question, "What ink system should we use?"

The generous participation of industry members plays an invaluable role in the success of this project. In addition to participating in the development of the methodology, members from all parts of the industry - substrate manufacturers, ink manufacturers, and the printers themselves - will be donating the materials and facilities needed to run the tests.

Structured Methodology

Designing the structured methodology that could yield meaningful information fell to the Project's Technical Committee. Together, experienced flexographers, trade association leaders, industry consultants, academic experts, and EPA scientists assembled a methodology that forms the backbone of the Project.

Samples of each ink will first go to the Printing Pilot Plant of Western Michigan Univ. (WMU). They will be run on WMU'S press, and the preliminary tests will be conducted.

One type of ink will then be sent to each volunteer facility for the field demonstrations. At each demonstration facility, the ink will be run on each substrate for two hours. Each ink will be printed on a total of three different films (see side bar). Plates will be provided through the Project, and the same image will be run at all facilities. While the structured methodology will minimize the site-to-site variations, differences in demonstration sites will inevitably lead to some inconsistencies. The Project members believe, however, that the benefits to printers of information gathered under actual production conditions far outweigh any such disadvantages.

Evaluating the Inks

Data gathered from the field will tell how each ink performs in three categories: performance, cost, and environmental/human health risk. After each field demonstration, the roll of printed film will be sent to WMU's lab for testing. A number of tests have been selected to answer the questions most often asked by printers: How does the printed ink look? How does it hold up under extreme temperature and handling stresses to which finished flexible packaging is subjected?

The data collected will also feed into the cost analysis. The cost evaluation will go beyond the purchase price of the ink to other factors that can affect how much it actually "costs" to use that ink. How much energy is consumed in printing and drying the ink? Does the ink have a high or low mileage? How many labor hours are required to produce the finished image?

Finally, environmental and health risk analyses will be conducted. These factors are playing an increasingly important role in the choice of the right ink. Does the ink contain hazardous materials, such as volatile organic compounds? If so, what risk does it pose to press operators and the public outside the facility? Are the ink chemicals regulated? If so, meeting regulatory requirements may add significant costs.

Findings will be compiled in the Project's full technical report, Flexographic Inks: Cleaner Technologies Substitutes Assessment (CTSA). The most pertinent and helpful information from the CTSA will then be summarized in shorter outreach documents. These simple, action-oriented bulletins will put the information where it belongs - into the hands of press operators, print shop owners, and other workers who have the power to translate it into educated decisions and real process improvements.

Partners in the DfE Flexography Project include: California Film Extruders and Converters Assn., Flexible Packaging Assn., Flexographic Technical Assn., Industrial Technology Inst., National Assn. of Printing Ink Mfrs., Plastic Bag Assn., RadTech International, N.A., National Inst. of Standards and Technology, Tag and Label Mfrs. Inst., Univ. of Tennessee, Western Michigan Univ., and individual printers and suppliers.

The DfE Program welcomes the participation and input of flexographers. For more information about the Design for the Environment Program, contact EPA's Pollution Prevention Information Clearinghouse (PPIC); US EPA, 401 M St., SW (3404); Washington, DC 20460 ph: 202/260-1023; fax: 202/260-0178; e-mail: ppic@epa mail.epa.gov; web page: http://es.inel. gov/dfe.

Inks: Three ink types will be demonstrated:

* solvent-based

* water-based

* UV-curable

Substrates: Each ink will be printed on three substrates:

* oriented polypropylene

* low-density polyethylene

* polyethylene/ethyl vinyl acetate

Laminates: The oriented PP film will be reverse printed and used as a laminate.

Press: Demos will be run on wide web, central-impression presses at speeds of 300-500 ft/min.

Color: Parts of the demo image will contain line and process colors with process tones in multiple gradations. Process colors will meet with 50% trap of tones and solids.

Lab Tests: Up to 21 tests will be conducted for each printed ink/substrate combination, including:

* scuff and rub resistance

* tape adhesiveness

* blocking

* mottle/lay

* ice water crinkle resistance

* heat resistance/heat seal

* coefficient of friction

* print density

* coat weight

* trap

* dimensional stability

* tone quality/dot structure

* gloss (Gardner 60 deg)

Sun Chemical HD Plates

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