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FLEXO Magazine : April 2010
www.flexography.org april 2010 FLEXO 35 can compare a second and a third product to the initial base- line product. This is when the real utility of the tool comes into play, as comparisons can be made between the scenarios to aid in process decision-making. Figure 3 shows three different scenarios entered into the EFC. The first scenario, or “Baseline Product” depicts an .067 in. digital solvent sheet plate processed in New England. “A lternate Product 1” represents a digital thermal sheet plate, also at .067 gauge and processed in New England. The last column, or “Alternate Product 2” is for an .067 in. plate made from liquid photopolymer, once again, for purposes of consis- tency, processed in New England. It is important to note that the data that went into creating the EFC was modeled using actual manufacturing processes and recommended plate processing conditions. Compari- sons to competitive plate material may be inappropriate. Additionally, one should note that the results compute im- pacts from raw material extraction to the imaging and process- ing of the plate, as part of a cradle-to-gate LCA. So while some numbers may appear unwieldy, one must consider the effect of the raw materials in the overall environmental impact. Compared to digital solvent processing. Whereas each individually modeled scenario will produce slightly different results, we can see from the scenario created in Figure 3 that, compared to digital solvent processing, liquid processing results in higher water consumption (40 percent) and smog generation (89 percent), yet has significantly lower impacts in all other categories. Upon closer examination of the smog generation impact, one will notice that the initial number of nitric oxide equivalents calculated by the EFC (1.8x10-6, or .0000018 kgs) is so low that even a very small change in the quantity will result in a large percentage increase. Compared to digital solvent processing, digital thermal processing has a slightly higher impact of eutrophication of water (7 percent), but has lower impacts in all other catego- ries. For example, water consumption is 59 percent lower and the CFC equivalents produced (ozone depletion impact) are 60 percent lower than with digital solvent. Compared to digital thermal plate processing. Liquid and solvent plate processing use much more water than thermal plate processing. Digital thermal processing uses consider- ably less water than the other two processes because: • liquid platemaking uses water instead of organic solvent • the raw materials used to develop solvent use much more water than the raw materials required to produce blotter material. So while digital thermal processing uses less water than the other two process, liquid plate processing consumes less energy and contributes fewer CO2 emissions to the atmo- sphere (Global Warming Impact). Compared to liquid plate processing. Digital solvent processing consumes much more energy than liquid plate processing. The culprit has been identified as the consider- able amount of energy usage required by the solvent still. Ad- ditionally, compared to liquid plate processing, digital thermal processing produces fewer kilograms of CFC equivalents than liquid platemaking. The overall environmental advantag- es of liquid platemaking are so strong because a) un-imaged liquid photopolymer can be reclaimed and put back into the process and b) no solvents are used. Additional scenarios. While there is room here to examine the results of one potential platemaking scenario, there are literally hundreds of possible scenarios that can be created using the EFC. More information about other potential scenarios can be found at www.macdermid.com/printing/sustainability.html. CONCLUSIONS One conclusion resulting from the development of the EAC is that, generally speaking, the environmental footprint of solvent plate processing is greater than the environmental footprint of thermal plate processing. However, the environ- mental footprint of thermal plate processing is greater than liquid plate processing. An easier way to represent this in terms of footprint size: Solvent > Thermal > Liquid Although simplistic, this finding held under all scenarios studied. The advantage was especially pronounced for thick plates, where thermal processing is not currently practiced, and where the mass yield advantage of the liquid reclaim step gives a profound advantage to liquid platemaking tech- FIgUre 3: Compared to digital solvent processing, liquid processing results in higher water consumption (40 per- cent) and smog generation (89 percent), but is lower in all other categories. TEchnologies & TEchniques FLXApril10_mech.indd 35 4/10/10 1:22 AM
Sustainable Winter 2010