When we speak about the durability of labels in a general way, that can mean a lot of things: long lasting, tough, strong, adherent, or chemical, heat, abrasion, and wear resistant are a few characteristics we might name. But sometimes some of these durability characteristics can divert attention from those that are really important to the application. So assuming you are coming to this blog from the electrical utility industry or other markets requiring long-term outdoor durability, read on to find out what’s important.
Sunlight is the enemy
In markets requiring a label that exhibits long-term outdoor durability, the primary concerns are fading, shrinking, chalking, crazing, cracking, and peeling. And UV radiation from direct sunlight is the primary contributor to all of these modes of failure. So UV radiation is hands down the primary factor that renders a label used in continuous outdoor service ineffective towards its purpose.
Crack, Peel, Shrink Fade Chalking
All labels exposed outdoors and to continuous sunlight should be laminated
Consider this. Say I have a 10 year label material, and I print on it with an ink that when unprotected and exposed to continuous sunlight, typically exhibits fade in 5 years. So no matter how good the base label material is, the outdoor durability is limited to that of the ink. But if I protect the print with a clear film that I laminate over the printed base material, then I can extend the life of the print by as much, or nearly as much, as that of the clear laminate. But not all clear laminates provide the same level of protection. Some materials are inherently more resistant to, and screen out more of the damaging UV rays from sunlight. But also know that label materials generally perform best when the printed base film and protective clear laminating film are matched to be of the same type of materials; i.e. a polyester base film with a clear polyester laminate. This is especially true when dissimilar materials exhibit significantly different characteristics such as shrinkage rate, conformability, weatherability, tear-ability, etc.
What materials perform best in what application conditions?
Polyesters and vinyls are the most common materials that most graphics suppliers manufacture outdoor durable labels from. And they are both great materials where certain application conditions prevail.
Polyester provides about 7 years of performance against the deteriorating affects of UV sunlight before it eventually exhibits failure by chalking up and the print it protects exhibits fade. Seven years is still reasonably good UV performance; but polyester is also especially tough, exhibits very good chemical resistance, and excellent heat and abrasion resistance. Therefore, polyester can be concluded as the label of choice for the interior of equipment cabinets where heat and contact with oils may be a factor, for luminaire identification where labels are exposed to heat from equipment and are on the down facing side away from direct sunlight, or on power equipment where abrasion and wear are factors and exposure to sunlight is not continuous. But Electromark has materials that provide better performance when it comes specifically to the deteriorating affects of UV sunlight.
Many high quality cast vinyls provide up to 10 years of performance against the deteriorating affects of UV sunlight before they eventually exhibit failure by drying up and cracking and shrinking. But these vinyls are also very conformable, exhibit excellent petroleum-base chemical resistance, and are designed for cut-to-shape type decals. Therefore cast vinyls become the material of choice for use around fueling areas or for vehicle/fleet marking where cut-to-shape logos and letters are common, and application surfaces which may have compound surface contours. And beware that not all vinyls are created equal! There are calendared vinyls of lesser durability that are designed to provide a conformable material at a lower cost. And similarly to the comparison to polyester, Electromark has materials that provide equal or better performance when it comes to the deteriorating affects of UV sunlight; albeit at a lower cost than premium cast vinyl.
But what’s the best for the deteriorating affects of UV rays?
When prevention of the deteriorating affects of UV rays is the primary application concern where your labels are utilized, Electromark’s premier material is Duracryl®. By proprietary definition, Duracryl® is a laminated construction of screen printed base film and protective clear film materials that are chosen because they provide superior UV resistance and competitive cost. Simply put, UV resistance is what Duracryl® does best!
Electromark’s Duracryl® labels are warranted to remain effective towards appropriately intended applications for an honestly represented 10 years outdoors. And I routinely see them still looking good at 12, even 15 years! This is especially true where critical safety labels need to not only remain readable, but the brighter safety colors used in the headers need to remain recognizable.
Electromark also has polyester, vinyl, and retroreflective label materials where other application conditions are a primary factor or need to be balanced with the need for UV resistance. Call your Electromark representative for best recommendations.