Photos courtesy ARC
By Renaat Demeulemeester
Raw film manufacturing plays a critically important role in the development of the vinyl materials used extensively as printable substrates in the graphic arts industry. Indeed, the companies that manufacture these vinyl films are often leaders in the advancement of polymer science to support new capabilities and applications.
Film fabrication
There are essentially two types of vinyl films that are used for a wide range of graphic art applications: cast and calendered.
The terms ‘cast’ and ‘calendered’ refer to different manufacturing processes. These processes, along with varying constituents added to the raw materials, render very different qualities to the films.
In cast manufacturing, a liquid is poured onto a carrier sheet, which is then heated in ovens. No stress is involved in the process, so the sheets suffer no shrinkage.
Calendered vinyl, on the other hand, is produced in a continuous process, which enables high-volume, low-cost manufacturing. On the calendering line, the raw materials are mixed together, extruded and then flattened out into a thin film by passing them through a series of heated rollers.
Historically, these two types of films have differed markedly in terms of their quality, including both durability and flexibility. Cast films have traditionally been considered the industry’s premium option, as they are more suitable for applications that require greater strength, resilience and superior handling, particularly for longer-term outdoor graphics. Calendered films, meanwhile, were largely relegated to short-term outdoor graphics and indoor applications, due to their less robust nature.
Today, however, the discrepancy between cast and calendered film quality is not nearly as great. Ongoing improvements in both the manufacturing process and the selection of ingredient additives have allowed the development of much higher-performance calendered films than in the past.
While cast vinyl has long been the preferred choice for graphic applications involving wrapping and stretching, calendered vinyl has now undergone sufficient improvements, to the point where it can now compete with cast vinyl.
