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UV-Curable Technology, Part I: The Ultraviolet Media Debate
Ultraviolet (UV) curable inks and coatings are nothing new. But major players are stepping up to the plate with 21st century technologies designed to bring UV into the mainstream - finally.
The Information Management Institute recently held its first-ever UV Ink Jet Symposium to introduce the printing world to the basics of UV chemistry, formulations, hardware, curing and safety issues, marking the beginning of a UV revolution. As ink jet printing continues evolving in functionality, cost performance, print quality and color printing capabilities, the interest in UV ink jet technology is set to explode.
Indeed, there is no doubt that UV-curable printer technology is changing the world of digital printing. High production ink jet machines allow you to print on both flexible and rigid substrates up to 3 inches thick and uses ink that dries instantly, which reduces your production times and ultimately saves you money.
Manufacturers like Avery Dennison and 3M are launching products that target the sign industry, but these staunch competitors are on opposite sides of the fence when it comes to what media is necessary to get the best results from UV technology.
Avery claims it is the perfect media match for applications such as point-of-purchase displays, tradeshow graphics, and other indoor and outdoor signage. The product line consists of three products - one calendered and two cast vinyls - that feature 100 percent clean removability.
Avery’s UVM line offers permanent and removable adhesives for short- and long-term graphic applications and guarantees a five-year durability with an overlaminate or three years without an overlaminate. UVM is available in 48”, 54” and 60” widths. Prices run a little higher than Avery’s solvent products.
“Even though UV printer manufacturers say you can print on any substrate, you don’t always get the best results printing on just anything,” says Avery Dennison spokesperson Tiffany Witham.
For example, if you print on a raw piece of vinyl that has no coating on it, she explains, then you might get an image that would satisfy your needs in terms of colors. But from an ink adhesion standpoint it is less than ideal because you could scratch the ink off very easily.
“Ink manufacturers are claiming that their inks will last two years from UV-resistance standpoint - and that’s great,” says Witham. “But if you can go scratch it off the vinyl, then it doesn’t really matter.”
The Tape Test
That criteria is called the crosshatch tape test. This entails using a rigid metal tool that looks like the end of a tape dispenser to make two X-shaped scratches at 45-degree angles. Then you place a piece of 3M tape over the scratches in the middle of the “X” and let it sit for about one minute. The goal is to remove the tape without lifting off any ink.
“If you do the crosshatch test on raw vinyl, then you will lift up ink,” says Witham. “Depending on whose raw vinyl it is, you’ll lift up more or less.”
Witham says UVM was designed for ultimate ink adhesion. So when you perform the crosshatch tape test on the UVM line, no ink comes off. That, she says, means you could go outside with a piece of vinyl on which you’ve printed a message with your UV-curable inkjet equipment and you don’t have to worry about scratch resistance.
“It takes away the need, to some extent, of having to do an overlaminate to protect the graphic,” says Witham. “So that takes out cost from a materials standpoint and also from a production standpoint because you don’t have to run it through a laminator. That’s the big key here.”
Witham admits that Avery’s cast material durability is somewhat dependent on the ink manufacturer’s warranty. She says Avery knows its vinyl will perform and printer manufacturer technology will perform, but the ink itself is still the limiting factor in the equation.
In fact, one area that Avery does not recommend UVM at this point is in fleet wrapping. “Going over rivets and corrugation for a long period of time causes us concern because the inks aren’t quite good enough yet,” says Witham.
“We are in the process of testing and qualifying several films and other materials for use with our new printer,” says Anthony Carrozzella, a spokesperson for 3M’s Commercial Graphics Division. “For the most part, these are the same materials we sell for use with other printing platforms.”
Carrozzella says 3M has spent the last six months rigorously testing each material to discover which media the company can qualify for use with its new UV printer. This testing is not only limited to 3M graphic films, but will include a number of rigid substrates and textiles and will complement the broad range of applications that the new printer offers.
“As a result of introducing a complete system hardware, software, UV inks and materials there is no need for us to introduce a special line of films to be compatible with our printing system,” says Carrozzella. “In fact, we have produced 3M Graphic Marking Films for UV printing technologies for over 10 years.”
Carrozzella insists that the media itself is not a big deal. The company’s core film technologies will be compatible with its new printers and inks. The key, according to 3M, is having a complete top to bottom UV system for the UV-curable printing platform.
“The whole system needs to be optimized to work together,” says Carrozzella. “If you take one company’s media and another company’s inks and a third company’s printer, then there is no guarantee that they will create a quality graphic simply because they have the term ‘UV-curable’ on them.”
Agreeing to Disagree
Avery executives are betting on the market’s need for advanced UV media. The company plans to introduce new products to round out UVM in the coming months.
“The downfall of the UV-curable technology is that the inks are not extremely flexible,” says Witham. “However, we are still in the beginning stages of the technology so the ink formulations are always changing. Printer manufacturers and ink manufacturers are working together to get those ink sets to where they have both the rigidity and the flexibility they need.”
3M, too, believes that UV technology is the future of large-format printing. Still, neither company dares to predict whether or not UV could eventually replace older printer technologies.
“Look at electrostatic technology,” says Carrozzella. “People have predicted its demise for years, but we just introduced a new dye-sublimation technique for continuing to get the most out of this printing platform. So, it has proven harder to predict what will remain and what won’t in this industry over the years.”
In parts two and three of this three-part series we will take an in-depth look at UV inks and UV printer technology.
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