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FLEXO Magazine : April 2014
Electron Beam Curable CI Flexo Ink Technology Over the past decade, some of the most prestigious ink companies have been hard at work developing electron beam (EB) cured alternatives to today’s conventional solvent based central impression (CI) flexo inks. Sun Chemical first intro- duced WetFlex several years ago as an EB curable alterna- tive. A water based EB platform which improves the physical properties and adhesion challenges faced by conventional water based inks is scheduled for release later in 2014 as well. And now, another new EB curable flexo ink technology platform has arrived: GelFlex-EB from Techno Solutions. It promises to offer the marketplace both an economic and an en- vironmentally sustainable alternative to current solvent systems. BETTER QUALITY Flexible packaging printers have always been striving to im- prove quality and consistency. To this end, wet trapping of 100 percent solids EB curable inks has been in use for decades on web offset presses to produce best in class graphics. And with the recent advancements and cost reductions in web offset press technology, this process and these EB inks continue to gain share in flexible packaging. These same physical properties and characteristics avail- able in offset are now available on CI flexo presses with GelF- lex-EB: They include180 lpi (70 lcm) for higher resolution and tonal value, 50 percent less dot gain for higher contrast, bright- ness and smooth vignettes, smooth ink laydown, reduction in graininess, and higher solid ink density, the broadest range of physical properties, gloss, abrasion and scuff resistance, and chemical resistance. REDUCED COST But customers don’t want to pay more; in fact, they strive for planned year over year cost reductions. To most printers, this is the biggest reason GelFlex-EB inks will make so much sense: cost reduction. A GelFlex-EB installation will use up to 80 percent less energy with a typical EB using only 30-kW. to 40-kW. of electricity. Additionally, it will use 60 percent less color ink laydown and 65 percent less last down white ink. And since the last down white is made up of 100 percent solids, this further reduces both the amount of ink bought and the amount of solvents emitted. Printing is all about dots and dot control. GelFlex-EB ink is a high solids ink (like most EB inks) and that helps achieve a smaller and more consistent print dot. This allows the use of an expanded gamut ink system, further reducing both the number of colors used and the number of ink color changes. The result is higher uptime, more consistency and produc- tivity. And consistent with energy cured inks, the EB inks can be left on press between runs, shifts and even weekends. HOW IT WORKS The GelFlex-EB ink technology accomplishes wet trap- ping on the principles of organogel formation using Hansen’s solubility parameters. With GelFlex-EB, a small percentage of solvent (between zero percent and 15 percent) is added to adjust the solubility parameters of the ink. As the solvent evaporates from the first color, the ink immediately undergoes a phase change and becomes a hard gel, allowing the second colortolieontopofitandsoon. GelFlex-EB inks uses energy curable resins. The use of EB curing enables adhesion to difficult substrates and compliance with global food laws as measured by a test laboratory accred- ited by Dakks according to DIN EN ISO/IEC 17025. Testing was done on reverse printed OPP film printed with five colors and last down white. Conditions were worst case to cover long time contact with fatty foods up to 40 degrees Celsius. For curing of ink, low voltage EB equipment like the FlexoBeam from Energy Sciences, Inc. at the end of the printing process. Typical EB conditions to cure these inks are 110-kV., and 30-kGy. To 35-kGy. (kilograys), permitting speeds of about 1,312 fpm (400 meters per minute). Testing has been accomplished for long run lengths 164,000-f . (50,000-m.) at a speed of 820 fpm (250 mpm) with no change in print quality from start to finish. Uteco has led the way in press development for this type of CI flexo ink. Requirements from CI flexo printing press are closed doctor chambers, a pumping system that must be ca- pable to work in a recommended viscosity range of 300 cP. to 500 cP., a thermoregulation system to control the temperature of the inks in the range of 30 degrees Celsius to 35 degrees Celsius is highly desirable A dynamic use of GelFlex-EB occurs when looking to print and coat inline, or print and adhesive laminate inline, or print and crosslink inline. The formulation of the GelFlex-EB inks allows for all of these inline processing options with just one EB machine located at the end of press. The GelFlex-EB inks can be applied on various substrates including various papers, films, heat shrinkable film tubes and foils. Printers today are under constant pressure to maintain graphics quality while delivering year over year cost reduc- tions. GelFlex-EB ink can provide both: Cost reduction through ink savings, waste savings and productivity gains, combined with better image quality and smaller dots—all while decreas- ing emissions 90 percent with an ink technology that is safe for food and sustainable. GelFlex-EB inks is a patented technology. The patents are already awarded in South Africa, Colombia and recently obtained a notice of allowance in the United States. Patents are pending in Europe, Asia and counties in South America. Contact Energy Sciences, Inc. at firstname.lastname@example.org or www. ebeam.com. ADVERTORIAL the world leader in EB and EB flexo Energy Sciences, Inc. 42 Industrial Way Wilmington, MA 01887 978.694.9000 www.ebeam.com email@example.com Conventional Solvent CI-Flexo Multiple Thermal Dryers Needed Dryers Dryer Dryer Dryer Dryer Dryer Dryer EB CI-Flexo NO Thermal Dryers Needed Flexobeam Significant energy savings with EB Flexo printing The next revolution in flexible packaging GravurE QualIty lowESt total prInt CoSt GrEEn platForm SaFE Come see us at INFO*FLEX 2014 Booth #924 See GelFlexEB article on p.11 ESI show ad 2014 Flexo.indd 1 3/11/14 6:37 PM