by clicking the arrows at the side of the page, or by using the toolbar.
by clicking anywhere on the page.
by dragging the page around when zoomed in.
by clicking anywhere on the page when zoomed in.
web sites or send emails by clicking on hyperlinks.
Email this page to a friend
Search this issue
Index - jump to page or section
Archive - view past issues
FLEXO Magazine : Sustainable EOY 2009
www.flexomag.com END OF YEAR 2009 Sustainable FLEXO 13 In the case of manufacturing photopolymer flexographic printing forms, the solvent washout process has established itself as a reliable production standard due to its productiv- ity, simple handling and efficient cost structure. If an effective contribution is to be made toward improving the environmen- tal impact on a global level, the long-term optimization of solvent-based plate processing needs to be the main focus. EXPANDING ON ADVANTAGES Washout of flexographic printing forms with solvents has a number of key advantages, such as: • Employees are familiar with the technology and pro- cesses. • Existing equipment can continue to be used. • Users can rely on a wide product range from various suppliers. • The available technology is suitable for all flexographic printing applications. • The entire range of formats is covered by various manu- facturers offering systems up to a maximum format of 52in. x 80in. • All plate thicknesses from .030in. to .250in. can be pro- cessed with the solvent-based method. • In comparison with the standard platemaking practice of processing several plates in parallel, the solvent-based method provides a high level of productivity and at the same time is particularly cost-effective. • As a high proportion of the solvent is recycled, the environmental impact is also very low. In addition to these fundamental benefits, the sol- vent technology has substantial potential to further improve the environmental impact of the process. IMPROVING THE CARBON FOOTPRINT According to Flint Group Flexographic Products, there are five highly efficient options for plate pro- cessing that contribute significantly to environmental protection with concrete measures. 1. As plate material has the greatest influence in terms of GWP (Global Warming Potential, see info box), the usage of plates that are as thin as possible is recommended. In this way, the switch from plates, for example, with a thick- ness of .067 in. to .045 in. plates, lowers the GWP contribution by 17 percent. The benefits here are not just felt by the environment, but users can also make production cost savings of up to 30 percent. 2. Solvent recycling plays a significant role. If the maxi- mum recycling rate of 90 to 95 percent can not be achieved with the company's own resources, it may be worthwhile to use external recycling capacities. 3. In this context, it is also important to select an environ- mentally-friendly washout solvent. 4. The use of efficient processing and drying equipment offers considerable potential for optimization. 5. Last but not least, particularly for complex process systems like packaging production, the entire process, e.g. flexographic printing, should be evaluated to define further opportunities for improvements. Potential obvi- ously exists, starting with substrates or printing inks right through to the service life of consumables such as sleeves, etc. ECONOMY AND ECOLOGY BALANCE The practical use of the solvent technology has been driven by continuous developments over the decades. Decisive progress could be made with the chemical composition of washout solvents, solvent recycling and washout equipment technology. To a great extent, flexographic printing plate manufacturers did contribute to these key developments. As much as 20 years ago, suppliers have offered chlorine-free washout solvent on the commercial market. Fully automated systems to washout flexographic printing plates in a continu- ous in-line process are also available. In addition, some com- panies facilitate the installation of efficient solvent distillation systems through special financing options. Key environmental aspects are usually considered for product innovations and developments and are generally seen in relation to the cost-benefit ratio. This is also stated in the Eco-Efficiency Analysis (EEA), which Flint Group Flexo- graphic Products published in mid 2008 (see Sustainable FLEXO, Fall 2008, page 12). This comprehensive study fo- cused on a comparison between the proven technology of the solvent-based washout of photopolymer plates and thermal technology. The data from the report showed that the solvent technology--which makes up 95 percent of the global market-- has a cost benefit of 10 percent or more, while CO2 emissions are also advantageously low. LIMITED OPTIONS For the user, it is critical that the comparison of the two processes is not limited to ecological and economical factors, but also considers further relevant aspects. For example, in the thermal method, the selection is limited in the number of suppliers and format categories (usually 42in. x 60in. and 36in. x 47in.). The same applies to the plate thickness, which is restricted for the thermal processing to between .045in. and .112in. As a result, market segments such as corrugated post print can only be sufficiently operated with traditional manufacturing methods. In addition, the limited format selec- tion has a negative impact on the quantity of waste produced during plate making. The maximum format of the processor cannot be fully utilized for each job; nevertheless, the entire web width is completely consumed. FIGURE 2. The selection of an ecologically beneficial washout solvent reduces the impact to the carbon footprint.