Specialty Ink

By Jack Kenny | July 20, 2005

Products attract attention when packaging inks display unusual characteristics.

Product marketers want their packages and labels to do something — really do something — to the eyes and minds of the people who see them on the shelves and elsewhere. That's what keeps this industry in business, and that's why converters are pushing out into niche markets.

But not everyone can make shrink labels or lenticular panels. What do you do if your printed product features a simple two-dimensional image? You play with light, and you play with color. Consumers are attracted to shiny things, just like barracuda (Tropical divers understand this all too well.). If it glitters, shines or glows, there must be a reason inside the package.

Specialty inks give a label that extra pizzazz, and lately the interest seems to be growing. "People are definitely looking more at glow-in-the-dark inks, and at thermochromic inks," says Dave Elliott, marketing manager at Craig Adhesives & Coatings, Newark, NJ.

"Thermochromic, luminescent, pearlescent and metallic inks are the biggest in the specialty category today," reports Ed Dedman, market development manager at SICPA, the Swiss ink manufacturer whose North America headquarters is in Brooklyn Park, MN.

Add to that mix photochromic inks and optical variable products, and you have a good list of specialties for turning an otherwise routine print job into a stand-out. Specialty inks pose some challenges to printers, but with use and education they are eminently manageable. To the packaging customer metallic inks can provide a less costly alternative to foil stamping, and to the converter that will translate into a faster press run.

One significant consideration is price. Metallics, fluorescents and other unusual inks and coatings come with a price tag. The ingredients used to make them are costly.

Metallic inks
Perhaps the most popular of the special-effect inks on the market today are the metallics. "In general, they are the inks most in use in the decorative specialty ink category," says Mike Buystedt, director of market development for Akzo Nobel Inks, Plymouth, MN. They have been around for years, of course, but the old standbys have given way to a new generation.

"Vacuum metalized pigment inks are getting a lot of attention lately," Buystedt adds. "The technology used in their manufacture results in very bright silvers, simulating foils. We can't do it yet with golds, but we're working on it and expect to have a product in about 18 months."

Photo courtesy of Akzo Nobel Inks

According to Norbert Hobrath, the director of marketing communications and services for Eckart America, Painesville, OH, the vacuum metalized pigment (VMP) process "produces an ultra-thin aluminum dispersion. It gives ultra-brilliant reflectivity because of the high leafing characteristics." Hobrath illustrates the difference between conventional and VMP metallics this way: "Imagine a group of small mirrors on the surface of a table that has a lot of bumps in it, so that the mirrors reflect in many different directions and angles. That's conventional metallic ink. In VMP, all of the mirrors are lined up together, all facing the same way, giving ultra-reflective properties."

"It's the biggest new development," says Dedman. "These are extremely high brilliance products designed to replace foil. They tend to work best on clear film in reverse print applications. The film is a lens for that metallic ink. Some people are printing straight metallic with regular inks in front of them to tint or shade the metallic. You can mix colors into these to shade them. There's a lot of interest in that in the marketplace."

According to Dedman, one of the drawbacks is that "the best of those is a solvent based product. Not all of them are, just the high brilliance foil replacement type products. There are water based and UV curable inks as well, but you will not get quite the brilliance that you do by printing the solvent based inks."

Buystedt says that the solvent VMP silver "is very bright, just like a mirror when it's reverse printed on clear polyester material. The same material using a water based or UV curable silver is not as great. It looks more like a matte foil."

"They're a lot better than the old product," says John Signet, marketing manager for Water Ink Technologies, Lincolnton, NC. "The sheen doesn't approach foil stamping, but it gives converters a nice option to take to their customer. We have had a couple of instances where the ink has replaced foil.

"Some of our customers are floodcoating the substrate with metallic and trapping ink overtop of it," Signet adds. "That's a bit of a challenge."

"The biggest interest by far is in the VMP inks," says Hobrath. "Printers see the value of running presses faster. If you're doing in-line foil stamping, you really have to slow the press down to make sure it stays in register. With inks, you can really run the press and achieve the look you want as well, and less expensively."

Expense is an issue, however. "They are expensive in themselves," notes Dedman. "It depends on the amount of coverage and the length of the run. Even though high brilliance inks are costly, using them is typically cheaper than investing in foil and the equipment needed to apply it."

"VMP technology is very expensive," Buystedt says. "It can be $100 a pound or more for the ink. But the converter has to run the economics. Suppose you have to print two dots: If you have a 10" wide press and you're using foil, you have to use 10" inches of foil for those two dots, and you waste a lot of foil. With metallic ink it's far less wasteful. And you can print halftones with the ink, no problem."

"If you're covering an entire label with silver, you look at metalized paper as our first option," says Hobrath. "But if you're covering a lot of the label with white, you wouldn't use metalized paper. On film, now you can achieve a metalized look on the pouch and bag with an ink instead of a film/foil laminate. That will be a big thing in the future. It's already starting."

Press operators might want to keep an eye on the performance of metallics on press. Dedman says that most metallic inks do not have exceptional adhesion on films. In addition, they have minimal scuff and abrasion resistance, and the usual ink additives cannot be utilized because they are incompatible with the resin chemistry.

"They're a little foamier," adds Buystedt, "but not that difficult to run. If you're running water based metallics on uncoated paper, it has a tendency to back up on the plate because the binders soak into the stock and the pigments hold onto the plate. That causes piling on the plate surface, and that could be a challenge. Running a different material often helps."

Millions of metallics?
New on the metallic ink scene is a company called MetalFX, based in Guiseley, England, which has attracted significant attention worldwide. Armed with the knowledge that a printer can lay down a silver metallic ink and color it by the addition of transparent process color inks on top, MetalFX devised a software system that guides printers in the creation of colors — hundreds today, with the possibility of millions tomorrow.

"The idea of overprinting CMYK onto a silver base has always been there," says Andrew Ainge, managing director of MetalFX, "but I was amazed that no one offered such a system already. I then began to realize that there was a definite gap in the market. We could see that potentially millions of metallic colors could be printed by adding only one ink, so we set about developing a system to achieve this."

Marks & Spencer and Safeway are planning to incorporate MetalFX technology into their packaging, Ainge says. And his process has drawn such companies as Eckart, Kodak, Creo and Gretag Macbeth to explore its expansion. Eckart, for example, is working on the MFX range of silver base inks for different print platforms.

"It's a prepress design based tool," says Eckart's Hobrath. "What it tells printers is 'See how easy it is to metalize your package using only five colors.' By putting silver down first and process colors after that, and by altering the way the colors are introduced, you can get up to 104 million colors." The present MFX range features 615 identified colors, but the possibilities through minute color variations are in the millions.

Right behind metallics on the packaging interest scale are pearlescent inks. "These can be UV curable or water based," says Jim Wittig, vice president of Rad-Cure, Fairfield, NJ. "Traditionally pearlescents are modified mica platelets in different types of inorganic coatings, typically based on titanium dioxide or iron oxide. Those coatings give the mica its iridescence or the interference pattern that results in the pearlescent look. Those platelets have been incorporated into flexo and screen ink systems."

Original colors in pearlescents were "kind of off-white," Wittig says, "but now they come in a wide variety of colors." They are more abrasive than normal coatings are, and converters usually try to avoid diecutting through the ink.

"Pearlescents have been around for a number of years," says Dedman of SICPA. "but some advances in pigments lately have made them more runnable, giving a better effect on typical films. They were harder to use in the past because they were dusty, but now they're easier to use."

"One challenge with pearlescents is trying to match the ink to the customer's product," says Elliott of Craig Adhesives & Coatings. "If you look at the products that are pearlescent themselves, there's a ton of pearlescent material in them. So getting the label to match is a challenge, because it's not as if the ink is saturated with it."

Photo courtesy of Akzo Nobel Inks

"Pearlescents have a tendency to fall out a bit," notes Buystedt of Akzo Nobel. "Printers have to be aware of phase separation with the pigments; the pigments could settle during a long run, so you have to stir them up."

Fluorescents, thermochromics, photochromics
"We get a lot of requests for unusual glow-in-the-dark inks," says John Signet of Water Ink Technologies. "We had one for a glitter version. Some are very hard to work with; we can make the formulations but they are difficult. The size of the particles inside the ink have to be of a size where they absorb enough light. That type of ink works better in screen printing than in flexo."

Labels produced using MetalFX's silver-plus-CMYK process.

Fluorescent inks, as well as those that change in appearance upon exposure to light or temperature changes, offer printers and packagers the variety they are looking for. Thermochromic inks are those that react to changes in temperature, and can be formulated to work with cold (beer labels, for example) or hot triggers. Photochromic inks are those that change color, or appear, upon exposure to UV or sunlight.

"We got a call from a cosmetic company," recalls Elliott, "that markets a hot oil treatment. They wanted a thermochromic ink on the tube that gets dropped into hot water, so that the consumer will know when the right temperature has been reached." Such inks are also used in medical applications, such as for sterilization in autoclaves.

"Specialty inks give diversity and an edge," observes Signet. "Prime label converters are always looking for that extra value to add. These are items to consider and to present to the customer."