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Flexo Sustainable : Spring 2012
inks might use the NAPIM BRC seal as a testament to the bio- renewable content. Further information on the BRC index may be obtained at www.napim.org. Important ConsIderatIons One increasingly essential question is whether or not so- called sustainable inks are biodegradable. Most printing inks are complex mixtures of resins and additives. While these inks may contain components from bio-renewable sources, their tendency to decompose in a landfill environment is hard to predict. Since inks make up very little mass (usually between 0 and 1 percent) when compared to the packaging or substrate used. Walmart has exempted inks and coatings from its scorecard activity at this time. What happens to the dried ink film during the recycling process? Printed packages are recycled every day. Consider- ing the corrugated packaging industry specifically, millions of tons are recycled every year. Much of this can be recycled into kraft paper without any issues arising from the nature of the inks. In some cases, the inks and adhesives must be removed by means of the aqueous de-inking process. The ink and adhesive waste is isolated, usually by means of a flotation process, before being collected by means of a filter press. The sludge is disposed of in an appropriate man- ner that may include burning as fuel and incorporating into concrete as filler. Can we calculate the carbon footprint of ink? To accurately determine the carbon footprint of ink, considerable effort is needed to isolate the specific inks utilized on a particular press. Since inks tend to be custom-tailored for a particular set of operating conditions (color, press, plant, substrate, drying, etc.), it would be a monumental task to determine the carbon footprint of each of the inks. A few studies have been conducted to obtain estimates. It’s been reported that inks contribute only 0.5 percent toward the overall carbon footprint of the printing process, with the bulk of the contributions com- ing from the substrates. Another valuable source for pertinent information regarding inks, especially when comparing water-based inks to solvent-borne and UV curable inks, is the EPA’s 2002 report entitled, “Flexographic Ink Options: A Cleaner Technologies Substitutes Assessment. ” If ink is such a small contribution to the package is there re- ally any reason to consider the ink in sustainability programs? Yes, considering the formulation of the inks should play a role in any sustainable program. Any time plant-based polymers can be used to reduce petroleum-derived polymer content and reducing the volatile organic compounds in the ink for- mulation, the carbon footprint of the ink is reduced. Alterna- tive ink systems with reduced petroleum content can make a big difference. Additionally, an ink supplier should also have a demonstrated commitment to sound environmental practices surrounding the manufacturing process, including reclaim- ing process water and the use of reclaimed and recycled packaging as well as reclamation and recycling programs to offer its customers. plant- Vs. soy-based Inks Today, water-based flexographic inks are formulated to contain maximum levels of bioderived sustainable raw mate- rials for conventional and high graphics corrugated, narrow web and flexible packaging. These inks are manufactured with not only water, but with the highest level of plant-based polymers, which greatly reduces the amount of petroleum- based products commonly found in conventional ink formula- tions for packaging. There are no added heavy metals and VOCs are reduced. The reduction in petroleum-derived resins can be measured with a savings up to 16.9 -gal of petroleum oil per 450-lb drum of ink—depending on formulation and color. These next-generation systems offer several advan- tages over more conventional, soy-based systems. Water based ink systems, based on soy polymers, offer good printability, but these systems also have certain deficien- cies such as viscosity instability with a number of pigment types. It can also be difficult to produce highly pigmented inks required for today ’s fine line anilox rolls, due to the high viscosity characteristics of the soy polymer. Furthermore these types of inks can also offer inferior rub resistance proper- ties due to low resin content. Systems now on the market are formulated using the latest sustainable polymers, which allow higher resin loading that offset the disadvantages of soy- based ink. Such inks operate under a wider pH range than both conventional and soy-based inks and are designed to www.flexomag.com spring 2012 Sustainable FLEXO 9 Compostable packages feature biodegradable inks. photos: Cri
Year End 2011