Polymeric calendered vinyl with an adhesive that is both high-tack and removable is ideal for wall graphics.
Polymeric vinyl, also known as intermediate vinyl, uses a mix of several types of PVC resin with a greater surface area for those additives that extend product life or give special performance characteristics. The mix of materials in this construction can increase opacity, flexibility, UV durability, fire resistance, gloss, and so on. This is the category where most specialty vinyl lives, and the applications are vast. Wall graphics, floor films, and even some vehicle and fleet wraps, can all be found in this category.
Cast vinyl is different right from how it is formulated and mixed, starting as a solvated liquid that is poured out onto a paper or film casting sheet, heated to flash off the liquid solvents, and then fused to form a durable, high-performance film. The casting sheet will determine the finish of the film, and typically range all the way from ultra-gloss to ultra-matte. Cast vinyl for the graphics industry do not include any special textures or patterns like you would find in intermediate vinyl. The manufacturing process is much more complex than calendered and results in a material that has incredible stretch and conformability and can be formulated to have extended outdoor durability far beyond the capabilities of its calendered counterpart.
Cast vinyl is typically used for more complex, long-life projects such as fleet graphics or textured wall wraps. However, that film is just one piece of the puzzle, and film by itself can only go so far. For the material to work, it needs the second building block—glue.
When thinking about glue, things like sticky, high-tack, removable, permanent, peel, or bond come to mind. What about opaque, slideable, beaded, or repositionable? Perhaps solvent or water-based? All of these are components that can be designed into an adhesive, and all have applications where they are needed.
First, let’s talk about the difference between tack and bond. Tack is a measure of how much initial or quick-grip an adhesive provides. A high-tack adhesive will stick immediately to a surface it contacts, attempting to anchor to the substrate so it can build bond, or “adhesion over time.” Tack is right now; bond is over time. A low-tack removable adhesive is ideal for window graphics where the higher surface energy of the glass does not require a lot of initial tack for the adhesive to stick, and the removable adhesive ensures low bond for clean and easy replacement of the graphics when the promotion is over.
On the other hand, high-tack permanent adhesives grip and hold and will likely either leave adhesive behind when it is time to change the graphic, damage the substrate, or both. It is designed to adhere strongly right from the start, making it easier to stick to surfaces that otherwise would repel the glue, like low surface energy plastics, textured surfaces, wood, or powder coated metal.
High-tack removable adhesives have an initial grip, which comes in handy when sticking to flat finishes, low volatile organic compounds (VOC) paints, but maintains a low bond allowing the decals to be removed cleanly and easily when it is time to change out a promotion or redo room décor. Similarly, low-tack permanent adhesives, like those found in slideable vehicle wraps, have low initial tack to allow for easier alignment, and then build to a permanent bond with the addition of heat, pressure, and time.
