Improvements in films, graphics and production capacities continue to drive the flexible packaging market. With that, though, come challenges on the surface treatment front. How can corona and plasma treaters better prepare film surfaces for effective printing while keeping up with increasing line speeds and sustainability initiatives? How do these units handle the latest bio-based films and those that are still to come? Surface treatment suppliers have taken these challenges head on, and now, surface treating stations needn’t be considered a bottleneck on your press.
Energy-sipping electrodesA stigma often associated with surface treatment units concerns the immense amount of energy used to improve a film’s adhesion properties. Several corona treatment suppliers have changed this thinking with recent improvements in energy use and efficiency. In the last year, Hamburg, Germany-based Softal has made important progress with its Intellablade electrode, which typically reduces a treater’s power requirements by 20% to 30%.
“[Intellablade] saves energy, of course, but it also benefits the treated material,” says Peter Palm, Ph.D., Softal’s technical director. “Corona treatment is necessary for many applications, but corona can be overdosed. The more that you are able to reduce the required power for the treatment to get the proper effects, the more you reduce the unwanted effects that parallel corona treatment.” Potential drawbacks include efficiency loss or overheating of the substrate.
Softal also offers newer plasma technologies, including a gas phase plasma process that replaces primer coatings.
“We need just small amounts of gas to make really thin, sub-nanometer coatings to get the adhesion properties that the end user requires,” says Palm. He explains that plasma not only eliminates the material used in an adhesion-promoting primer coating, but the method presents inherent energy and emissions savings. “You’d have to incinerate the organic solvents and dry it, too. That is not necessary in a plasma process.”
QC Electronics also proffers efficiency and energy savings with its product, the new DT+2 bare roll treater. According to President Kenneth Klein, the new bare roll corona treater can reduce a printer’s treating costs by about 50%, an efficiency that’s driven by the design of the electrode.
“Our DT+2 electrode is adaptable to any type of corona treater,” says Klein. “The benefit the converter is going to see by doing this conversion is they’re running at 15 kilowatts (kW), but they can actually reduce their output power to 7.5 kW, achieving the same dyne levels, just by simply changing out the electrodes.”
The biggest benefit is lower operating costs not only from a smaller power draw, but fewer ozone emissions to deal with, too. “Because of the lower power settings, ozone emissions would be reduced accordingly. If you were running at 15 kW, now you’re running at 7.5 kW,” says Klein. “You’re going to have half of your ozone emissions.”
Ousting ozone emissionsCutting ozone emissions in half in the first place is one valid approach that printers can take to achieving their sustainability goals. A second strategy revolves around the destruction of ozone emissions, a fundamental concept in Pillar Technologies’ improvements to its corona treaters and ozone destruct equipment.
“The purpose of this ozone destruct equipment is to convert or reduce O3 (ozone) to O2,” explains Rob Hablewitz, business unit manager of surface treatment solutions at Pillar. “A proprietary design using both an inert alumina sphere guard bed followed by a manganese dioxide catalyst is used to accomplish this goal; no consumption of fossil fuels or subsequent emissions. A regularly scheduled maintenance program along with assuring an ‘out-of-doors’ final release point of this ‘cleaned air’ ensures environmental sustainability.”
In today’s business, printers understand that sustainability means both sustainable profits and environmental sustainability. Hablewitz explains that Pillar complements environmental achievement with cost-effective results in other advances including the new Intelladyne digital power supply, new equipment designs for the narrow web and wide web industries, plus controlled gas atmosphere (CGA) and modified gas atmosphere (MGA) style corona treaters for specialty industries.
Ensuring performance in bio and beyondBy design, surface treatment eliminates a phase in the printing process by optimizing the surface prior to printing. In keeping with the step-saving theme, Enercon Industries minimizes waste, scrap and downtime and ensures reliable performance through the architecture of both its treater and control interface.
“We have redesigned the control architecture of our power supplies to provide customers with a system that is easier and less expensive to install while providing a central operator interface for standard and advanced functions,” says Tom Gilbertson, Enercon’s vice president of application engineering. “Today, watt density control, proportional speed control, station diagnostics and fault logging are included with the power supply. Our engineers will custom program additional options based on specific customer requirements.”
Enercon maintains that full service mindset even as printers break new ground in polylactic acid (PLA) films and other bio-based substrates.
“Our testing has shown that our systems are effective at treating PLA and other bio-based films,” says Gilbertson. “When working with any new film formulation, Enercon recommends a lab trial to ensure there are no problems with surface treating. A simple change in slip additives can result in a different treatment requirement. Enercon offers customers free laboratory trials that can emulate an existing treater’s capabilities and can test their application across multiple corona, atmospheric plasma and flame surface treatment technologies.”
Static eliminationOne of the byproducts of surface treatment is a high static charge which may later prove problematic for printing presses. Static charges attract dust and may lead to printing flaws or jams, making static control after any type of surface treater a must. At first, printers may be hard-pressed to identify where static elimination meets sustainability challenges. But to Matt Fyffe, vice president and general manager at Meech USA, the relationship is clear.
“Static electricity can cause production problems and increased scrap rates. Our equipment can solve those problems,” says Fyffe.
Improvements to the Meech line, including status indicator lights and AC (alternating current) ionizers that generate four times more ions, suggest that innovation in the field is anything but static.
“We developed an add-on piece that measures the residual charge on a web after the ionizer. Then it will adjust the ion output of the ionizer to make it as close to neutral as possible.”
The Ion-Jet Super Air-Knife, available from TAKK Industries, combines both positive and negative ion output with a hard hitting curtain of air, eliminating static electricity and while leveraging benefits of high-velocity air cleaning.
“The static eliminating bar that we are now using is a more effective device based upon the engineering that’s designed into the bar,” explains Terrance Clark, sales manager. “Static eliminating bars traditionally have had a fairly short operational range, 1 to 3 inches, and packaging printers were really kind of restricted on how and where they would utilize this tool. The Model 400 static eliminating bar that we coupled to the Super Air Knife has an ionization range of up to 7 inches.”
No matter which advances in corona and plasma treating you choose to implement, the potential benefits to your operation and bottom line are clear. Effective printing on increasingly faster production lines and the latest substrates is closer than you may have previously thought. n
Web exclusive: Outlook on surface treatment's futureAs production lines run faster, films get thinner and budgets become increasingly tighter, where will surface treatment units end up?
“To achieve future business, to produce a product in this market, you’re going to have to be very focused on green,” says Kenneth Klein, president of QC Electronics. “And if you can’t produce a green machine, you’re going to be left behind.”
Indeed, the “green” theme may move from fad to fact of life. With that, downgauging-an area where suppliers have a firm understanding of this concept-and the variety of substrates will continue to influence the design and operation of tomorrow’s corona and plasma treatment.
“[Biaxially-oriented polypropylene] and the different [polyethylenes] are still the major films in flexible packaging and this will continue in many countries where there seems to be a trend to cheaper sources of these traditional films,” says Peter Palm, technical director at Softal. “We have observed that these films may be coming from the not so-well-known providers of the resins and have a tendency to be harder to treat. Together with the tendency of the films to become thinner, they also tend to be harder to treat with corona. But this trend is still very well [under control].”
In the future, just as in the present, static elimination will play an important supporting role in static treatment.
“You have to have ionizers and surface treaters. Nothing’s going to change on that,” says Matt Fyffe, vice president and general manager at Meech USA. “If anything, there’s going to be a higher demand for them. The machines and presses are running a lot faster than they used to. And as a press increases speed, it’s generating a higher static charge, so then you need better or more static control to keep up with the process.”