The Ups and Downs of Using Overlaminates
Overlaminates are becoming more and more widely used to protect images printed on a variety of substrates. Among those overlaminates are architectural finishes that add new life to signs and graphics that once had to stand on their own.
“Many laminates will have UV absorbers which will dissipate those—that harmful exposure of those UV rays. Some people mistakenly call them UV inhibitors, but a UV inhibitor is typically an opaque pigment that will reflect back the light as opposed to something that’s clear and will dissipate those harmful UV rays. Laminates do not have UV inhibitors, they have UV absorbers.
“UV inhibitors in laminates provide some additional protection from the degrading effects of light and sun, but not substantial protection; they act more like a sunscreen than a sun block,” said Nerenhausen. “The real value of lamination is that it provides rigidity, scratch resistance, a textured surface, and protection from ozone and other pollutants.”
Stadelman said, “To many manufacturers it’s adding materials to the films to make them last longer outdoors. To MACtac, it’s a little bit different. We don’t just make the films last a long time outdoors, we add a lot of other UV products to our formulas—whether it’s to the film or to the adhesive that’s there—to also protect the image; to protect the ink. We’ve got UV filters or absorbers built in to protect the ink itself.”
Matching Materials to the Job
With the wide variety of substrates available, it may not always be easy to choose the correct materials for the job. This can create a number of problems including delamination, failure of the adhesive, and irreparable damage to the final product. Experts claim that the best way to ensure the proper matching of materials to substrates comes through knowledge of the product including the end use plus a strong relationship to the client as well as the vendor.
Stadelman said, “Everything gets an enormous amount of R&D before we ever release it to the market. Typically, a rule of thumb is to try to match media to laminate film. So vinyl goes with vinyl, polyester goes with polyester, etc. I know that’s not always possible. For 80 percent of the applications out there, that is the right way to go. Sometimes, though, you need to put polycarbonate to vinyl. When we design our adhesives and our films we make sure that we not only have the right face stock but also an adhesive that helps maintain the same coefficient of expansion and contraction and shrinkage, if possible, so that one doesn’t shrink more than the other. Our adhesives are designed to help the media not change dimensionally; to not create failure in the field.”
Tony Caruso, Eastern region sales manager of Advanced Greig Laminators Inc. said, “Having a lam that matches the media is important. You can add lam to ink to increase the level of moisture—proof you still need lam to protect the image.
“When people think of laminate they think of plastic, but laminate comes in a variety of materials—hot and cold. Having the right lam is vital to the application. It’s important to try to match the laminate with the media.”
Caruso goes on to say that AGL is different from its competitors because it uses a different system and way of matching overlaminates to various materials. “We have a match component system that allows us to match the quality of media and laminate. Low melt for the inkjet market, high melt for the offset market. We also add the match component system to our packaging. Our charts show media and description and then match it to the corresponding material.”
Bellah said, “Different overlaminates offer varying degrees of optical clarity, conformability, UV protection, chemical resistance, and durability, so matching the material to the job is essential. Both of our overlaminates have a clear, pressure-sensitive adhesive and are applied without heat, are optically clear, and are designed to perform well with our perforated window graphics films. They have important differences, however.”
For example, Clear Focus offers two main products that have specific uses and criteria. ClearLam is a 1.5-mil polyester film designed for use on flat surfaces only—e.g., retail store window graphics. It offers UV protection and mark/scuff resistance. CurvaLam is a 2-mil cast PVC film made of high-quality, 100 percent polymeric face stock. CurvaLam mates well with our perforated window films, which are also made of PVC. It’s more conformable than ClearLam, which allows it to be used on items that have moderate curves.
