Here at SpeedPro Imaging, ALL of the vehicle wraps are created using a Cast Vinyl Film. We refuse to use calendered vinyl on any vehicle. One of the main reasons why cast is better than calendered is due to the different manufacturing processes. Below I will briefly explain the manufacturing processes of both vinyl’s and list the advantages of cast and disadvantages of calendered.
The term cast refers to the manufacturing process. The vinyl begins with a recipe calling for a list of ingredients known as the formulation. These materials are added to a bowl or mixing churn in a predetermined order while mixing at a specific speed and for a set amount of time to ensure a complete and consistent mixture. This liquid mixture, known as organosol, is then precisely “cast” onto a moving web known as the “casting sheet” and is then processed through a series of ovens which allows for the evaporation of solvents. When the solvents are evaporated, a solid “film” is left behind. The film is then wound up in large-diameter rolls for adhesive coating. The casting sheet determines the texture of the film. Because the vinyl is cast on the casting sheet in a relaxed state, this material offers very good dimensional stability. This process also allows the film to be very thin (most cast films are 2 mil), which helps with the conformability of the product. Material manufacturers recommend the use of cast films on substrates such as fleets, vehicles, recreational vehicles, planes or boats where the customer wants a paint-like finish that will last a long time, usually 5-12 years depending on how the film is processed.
ADVANTAGE OF CAST FILMS
-Shrinkage is the lowest of all vinyl films. Since the film has not had any stress applied during the manufacturing process it does not try to resume or shrink back to its original form.
-Durability of cast films is generally higher than that of other vinyl films.
-Cast films can be made very thin which produces a conformable product that allows application over substrates with rivets, corrugations, and complex curves. Also, once applied, the graphic is less vulnerable to abrasive forces.
-Cast films also maintain their color and other properties better than other vinyl films. This results in better performance of pigments and UV absorbers.
Like cast, calendered film also gets its name from the manufacturing process. It is formulated with similar raw materials as cast. These ingredients are mixed and later kneaded. Materials are rolled out using large heated, steel rollers from the vinyl into a thin sheet. This process is called “calendaring”. In the extrusion process the prepared fine powder mix (“dry blend”) will fuse together into a homogenous mass, called “the melt”. The next step – “the mill” – consists of two counter rotating rolls, which can be heated up to 350 degrees Fahrenheit. The melt is continuously pulled into the gap and flattens out due to the pressure and temperature that is applied by the mill rolls. When the strip reaches the calender rolls, it passes between multiple gaps which increase the temperature. After each gap the film becomes thinner and wider. The film is still heated when it reaches the embossing station where different pattern and gloss levels are applied to the film. Each surface requires a different embossing roll – e.g. to produce a high gloss film a different embossing roll is required but also a special setting of the whole calender line. Now that the film has received its final dimensions and surface it needs to be cooled down and transported to the last process stage of winding.
DISADVANTAGES OF CALENDERED FILMS
-Calendered films are usually thicker 3-mil upwards
-Conformability is less, and shrinkage is higher.
-Durability for calendered films is less (1-5 years)
I know a lot of this can be confusing, but all you need to know is that when it comes to vehicle wraps, SpeedPro Imaging has the knowledge needed to produce the best wrap possible for YOU. If you have any questions or would like to know more, please give us a call at (707) 755-3151 or visit our website.