Apart from the type of raw materials that are used at manufacturing, the manufacturing process and the type of plasticizer used create the main differences of vinyl films. Vinyl films can either be made by calendering or by casting. Each of these processes renders different qualities of films. Casting generally results in better quality films. The grade of plasticizer that is used to make the film flexible also greatly affects the grade of the film. Generally for pressure-sensitive adhesive films a choice is made between polymeric and monomeric plasticizers. for simplicity's sake consider polymeric to be the higher grade and monomeric to be the economy grade plasticizer. The combination of these factors greatly determines the durability of vinyl films.

Cast films, also known in the industry as premium, high-performance or 2 mil are considered to be a premium product with excellent durability and conformability characteristics. The term “cast� refers to the manufacturing process of this type of vinyl. Making a cast vinyl film is a lot like baking a cake. 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 specific speed and for a set amount of time to ensure a complete and consistent mixture. This liquid mixture, known as organosol, is then “poured� or 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 subsequent 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 or boats where the customer wants a “paint-like� finish that will last a long time, usually five to eight years depending on how the film is processed.

• Shrinkage is the lowest of all vinyl films because the “casting sheet,â€? not the film itself, is pulled through the machine. 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 due to the manufacturing method and the raw materials used.

• 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, this low caliper makes the graphic 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.

• The manufacturing process of cast films makes it easy to run small productions of special colors to match. It is relatively easy to change color during production making color matching in small batches possible.

extract: http://www.signindustry.com