Meeting rough applications is as smooth as silk for screenprinted labels
By Maggie DeWitt
A rubber squeegee pushes UV-cured ink through a fine mesh screen mounted onto a steel frame, laying down thick layers of color. The result is the toughest label on the market. And while some newer printing processes are starting to encroach on traditional silkscreen territory, none of the contenders can take a licking and keep on sticking quite like screenprinted labels.
"Flexo and digitally-printed labels look and feel almost exactly like screenprinted labels," said Mike Evans, marketing manager for Lancer Label, Omaha, Neb. The difference, he added, is in screenprinted labels' incredible durability and longevity in the face of environmental assaultsespecially harsh sunlightand the flexibility to handle wider formats and special shapes of all the printing processes, screenprinting deposits the thickest film of ink on a substrate and it is that film's thicknessas well as the type of colorant the ink containsthat chiefly determines the durability of label images.
Even a laminated offset or letterpress label will not stand up to sunlight like an uncoated screened label.
"Lamination forms a protective barrier against moisture and abrasion," said Evans, "but it doesn't shield the image on the label from the deteriorating effects of sunlight." However, the solventless, UV-cured screenprinting inks provide a colorfast image that lasts over timethree to five years is the average life span for screenprinted images of non-neon pigments.
In addition, most screenprinted labels are produced on weatherproof and waterproof vinyl and polyester substrates which offer dimensional stability.
Although the lightfast, high-gloss screenprinting inks are very resistant to chemicals and abrasion, an overlaminate can be applied to labels exposed to extremely harsh environments. Besides the additional protection, this imparts an aesthetically appealing overall sheen to the labela value-added feature for marketing purposes on consumer goods.
According to Evans, the screenprinting process also offers customers greater flexibility, especially when oversized labels are required. "You don't have the size restriction that often accompanies flexo-printed labels," he said. In addition, making special dies to accommodate unusual shapes is more cost effective with the screenprinting process.
Silkscreening has always been popular in the promotional products market since a number of different materials and products can be printed using the same equipment and artwork. But, more importantly, the vibrant, glossy colors and the slightly raised quality of the inks are eye-catching and pleasing to consumers, leading to a host of applications in folding carton and flexible package labeling.
According to Denise Hines, marketing analyst for Stouse, New Century, Kan., while it is not the case with other types of labels, there is no situation where a screenprinted label couldn't be specified. However, it is not always cost-effective.
"If a customer wants a label for soup cans or hair spray bottles," said Hines, "screenprinting may not always be the best choice. Generally these labels require a higher resolution for artwork and don't require the lasting durability that screenprinting offers." And while distributors should always strive to provide customers with the best possible solution, Evans cautioned that "it is also important to avoid an over-engineered solution."
It is also essential for a distributor to understand application and artwork specifications and then seek direction from the manufacturer. "If you give us the size, quantity, application and number of colors needed, we'll give you the answer," said Evans.
In the August issue of packagePrinting, Bob Yates, sales manager for Gallus, Philadelphia, discussed the use of screenprinted labels printed with "confidential inks" on the circuits and antennas of anti-theft devices. He also touched on time-lapse and temperature-sensitive printing for some food packaging productsagain using "confidential inks" not necessarily available to the industry in general.
Another niche market quickly on the rise is a logical and extremely beneficial outcropping of screenprintings' raised-textured inks. Tactile warning labels and Braille printing for the blind is being used on certain packagingsuch as chemical bottles. The process involves a special 200 micron mesh screen unit and a puckering additive to raise the ink higher after curing. And ink thickness is being touted as a valu-eadded advertising tool, giving products a new packaging look with greater shelf appeal.
Hines pointed out that technology is addressing some of the negatives bandied about concerning screenprinting. Improvements are constantly being made to the quality of screenprinting equipment and ink systems and the use of more combination presses and easier retrofitting is lowering manufacturing costs. "In conjunction with improved operational efficiencies, these trends are dramatically reducing product turnaround times," she said.