By Olivia Cahoon
Part 1 of 2
Digital flatbeds print on a range of materials, including plastics. These substrates provide an alternative to traditional substrates and include materials like acrylic, polycarbonate, polypropylene, polystyrene, PVC, and styrene.
In part one of this two-part series, we take a look at how plastics are optimized to print directly to digital and what these popular applications are being used for.
Popular Plastics
Plastics are used for indoor and outdoor signage. They create visually appealing prints and are durable enough to withstand high humidity and water. When utilized with digital print technology, plastics are used to produce high-quality, vivid prints that last.
Plastics are digitally printed to be neon, glow in the dark, and have a glossy or matte finish. “Digital print can be done in a variety of colors to create esthetically pleasing sign designs,” says Marina Batzke, general manager, American PERMALIGHT.
Ken Davis, Plaskolite sales representative, Davis Marketing Associates, adds that the flexible design of plastics allows it to print custom solid colors and gradients that are Pantone specific. They are printed one at a time in gloss or matte. Companies involved in interior design, office partitions, wayfinding, and architectural graphics tend to print plastics with custom colors.
Print service providers (PSPs) utilize the combination of digital print and plastics for projects like photo luminescent staircase identification signs for emergency staircases. This type of work generally requires varied messaging and therefore must be customizable, shares Batzke.
John McCurdy, marketing director, Coroplast, points out that plastic substrates creates lower costs compared to other materials like aluminum or glass. Plastics are also durable outdoors, lightweight, fabricated easily, and customizable. “There are a range of plastic materials to choose from, each with their own benefits,” he adds.
As today’s flatbed printer technology improves, plastic materials are used for more applications. John Smith, president, Vycom Plastics, sees plastics trending in settings for point of purchase (POP) displays, exhibits, and signage.
Corrugated is one type of plastic, ideal for indoor and outdoor, short-to-medium signage. It works well as yard signage and has a stable demand. McCurdy says that POP displays and pole signs are common products made with corrugated plastic.
Acrylic is another a popular plastic substrate. “Because of its low smoke and burn rating, acrylic has become the product of choice in museums, schools, and other institutions,” says Davis. He credits durability, clarity, and light transmission for the high level of appeal for this type of plastic, which makes it a product of choice in the display, exhibit, and signage industries.
Davis adds that the flexible design of plastics allows it to print custom solid colors and gradients that are pantone specific. They are printed one at a time in gloss or matte. Companies involved in interior design, office partitions, wayfinding, and architectural graphics tend to print plastics with custom colors.
Printing Plastic
Different types of plastics yield different print results. Some plastic surfaces can’t handle inks and toners as easily as others. Adhesion promoters are used to stimulate adhesion and prevent peeling and chipping.
Corona treatment is one process that affects the plastics’ printability. Corona treating is done to increase the surface energy of plastic films to allow improved adhesion of inks, coating, and adhesives.
To perform a corona treatment, a power supply is applied to a treater station that administers the power to the material’s surface. The end result is an improved coating quality and stronger lamination strength. McCurdy shares that corona treated materials have proper surface tension for optimum ink adhesion.
However, it is important to note that static can be transferred to the material during corona treatment. It can also occur in colder or dryer air. McCurdy says that after corona treatment, inherent electrical energy generally dissipates over time.
Deciding if a plastic needs corona treatment depends on the plastic’s surface texture and how it will affect the print quality. Davis believes the real importance for digitally printing on plastic is not if one plastic prints better than the other, but which provides the greatest longevity and durability. “Not using a product designed for the application can result in chipping and delamination of the ink,” he adds. “Adhesion promoters can also address any static issues if they exist, but this is very rarely necessary,” he adds.
Soft surfaces like polycarbonate are directly printed without adhesion promoters, but there is a slight sacrifice in brightness and light transmission, says Davis.
Smith adds that with expanded foam PVC materials, the density and surface hardness can affect the way the ink looks. “I have found the higher density materials make the prints look better,” he says, noting that expanded foam PVC is lightweight and is commonly used for exhibition stands and interior design.
Solvent-based digital printing inks don’t require surface preparation and the material is immediately ready to be printed. “Both polyester and PVC print equally well. It is more the benefit of the thicker rigid PVC sheets that they have a superior flush surface look,” says Batzke.
Printing on acrylic also creates a clear and clean image that is durable and versatile. “Material can be used as a printed substrate or illuminated to further enhance the printed image,” says Davis.
Static is a challenge with most—if not all—plastics. Davis points out that this issue is more prevalent in winter months when relative humidity is low. “Most printers have anti-static ribbons or other grounding devices so that they dissipate any static charge. Some use an ionized air gun to neutralize the static electricity prior to printing,” he adds.
Plastic Society
Digital flatbed advancements and corona treatments make it possible for PSPs to offer digitally printed plastics. Consumers look to plastics for high durability and vivid colors for indoor and outdoor signage. It’s commonly used for yard signs, photoluminescent identification signs, and POP displays.
In part two, we take a look at rigid plastic materials available in the market.
Click on the link above to get more information on the vendors mentioned in this article.
Dec2016, Digital Output DOPL1612
