Media and ink advancements add durability and increased color gamut to digitally printed output, however, the use of liquid coating and film laminates are occasionally utilized for protection and longevity. The installation process also benefits from added flexibility and thickness, making graphics easier to install.
Liquid coatings and film overlaminates are each ideally suited for specific applications. A number of factors play into this, including cost. The application process—hot or cold lamination—determines pricing as there is a range of hardware available from film to liquid laminators.
Additionally, certain coatings and films can only be used with specific ink sets. The adhesiveness of an ink on a certain substrate may bond better or worse depending on the coupled protective film or coating. This article discusses the solutions that overcome these compatibility issues, in addition to a general overview of available products.
When deciding between liquid coating and film laminates, consider the application and the desired lifespan of the output. Working within a common denominator of durability is essential to success and managing clients’ expectations.
“When selecting the right graphic protection for your application, remember that the component in your graphic—ink, film, or overlaminate—with the lowest durability influences the graphic’s performance life. For example, applying a lower cost overlaminate on a premium film may work for a short-term graphics,” recommends Mark Elvester, technical service specialist, 3M Commercial Graphics.
A benefit of liquid coating is the hard surface that it creates, which makes images resistant to scratching and other abrasive destruction during transportation and installation. Adversely, clean up of liquid coating can be time consuming and the lay down during application is slightly slower than film to ensure proper adhesion.
“Liquid coating pros are that it is more conformable, there are a variety of application methods, there is a low cost of entry—unless it is UV-curable, it can be a lower price than its film equivalent, there is process flexibility, and small batch customization is possible,” shares Nate Goodman, product manager, Drytac Corporation.
An advantage to using film laminates are the range of finishes available, such as matte to high gloss. Extremely clear finishes add dimensions to the visual nature of images. Other benefits include degrees of weather, fading, and skid resistance and available graffiti protection, making it easy to find the right grade for any output.
“The positives to film technology are that it adds rigidity to cast film, can be conformable, has limited cleanup, and economic and eco-friendly options such as polyester and polypropylene are available. The cons are that it can be more expensive and require trimming, which could lead to more waste,” continues Goodman.
Although it depends on what is right for an application, some feel the benefits of film laminates outweigh those of liquid coating.
“Film lamination provides more readily available choices in film finish and final application. There are various textures, gloss levels, and performance enhancements such as graffiti resistance and UV inhabitors, for example,” explains Ronit McGuthrie, product manager, SEAL.
Apply and Conquer
Each protective method comes with different application types. Print service providers (PSPs) administer liquid coating either with roll coaters, screenprint presses, or spray coating devices. Film laminates offer hot and cold application. User preference varies.
Pressure-sensitive films do not often require heat for their application process. The heat can, at times, change the integrity of an output’s shape.
“Arlon’s protective films are all pressure sensitive, which means that heat is not necessary when applying to printed substrates. Using heat can cause the laminate to stretch a little during the application, causing edge curl later as it cools and tries to shrink back to its original size,” explains Ritchie Daize, automotive business development manager, Arlon Graphics, LLC.
Heat-based lamination includes a larger upfront investment cost and considerable warm-up time. However, there are output challenges that heat relieves.
“With modern adhesive technology, hot laminating is not usually needed unless printing with UV inkjet inks. The inkjet printing creates a very light texture on the finished graphic that can allow air to be trapped under the adhesive of the overlaminate. This may give the finished graphic an appearance we call silvering. Using a hot roll laminator helps alleviate this problem,” advises Elvester.
While offering a few complications, heat application provides a positive application process and output presentation.
Manufacturers continue to improve ink sets. Advancements lead to the creation of protective products that collaborate with these updates.
3M partners with printer and ink manufacturers to ensure inks work as expected. “In this way we guarantee that a manufacturer using the combinations of components we recommend will produce graphics that we stand behind,” remarks Elvester.
As new ink sets arrive on the market, utilizing compatible protective coverings may increase PSPs’ revenues as well. “It is important to have laminators and protective films and mounting adhesives that complement these technologies. Finishing adds a revenue stream for PSPs, differentiates them from their competition, and allows them to add application capabilities that they would not be able to produce without a laminator,” advises McGuthrie.
Here is a roundup of protective products on the market today.
3M’s Scotchcal Luster Overlaminate 8524 is specially designed for textured surfaces. It can be applied on outdoor walls and columns and on applications for automotive, consumer goods, general industrial, medical, military and government, packaging, and specialty vehicles. It is ideal for die cutting and features good initial tack and adhesive clarity.
Advanced Greig Laminators, Inc. (AGL) offers its AGL Cover-Rite V2, a step-saving laminate with built in polyester premask. The premask assists in preventing issues like image curl, necking, elongation, and image distortion while also protecting the image from stretching during the installation process. Available from 38 to 60 inches, the pressure-sensitive cast overlaminate is compatible with either cold or hot laminators and aqueous, eco-solvent, solvent, latex, or UV inks.