Vinyl: Cast vs. Calendered
Vinyl: Cast vs. Calendered
When comparing Cast and Calendered vinyl, the differences are pretty significant. Whether you’re new to the industry or have been in business for awhile, the information below is priceless in determining what type of vinyl to use for your next project. The many different factors that come into play will determine how the project will look, perform, and last.
IEC offers many types and brands of vinyl you need to not only do the job, but do it right. After all, our customer satisfaction is just as important as your customer satisfaction.
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.
Some advantages of cast film are:
Shrinkage is the lowest of all vinyl films because the “casting sheet,” 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.
Like cast, calendered film also gets its name from the manufacturing process. These films may also be referred to as intermediate, 4 mil, short-term or economy. Calendered vinyl is formulated with similar raw
materials as cast, except that no solvents are used. The batch is mixed and heated to a molten state that resembles pizza dough. Once the film reaches this molten state it is extruded through a die and is then fed through a series of calendering rolls. These polished steel rolls progressively squeeze and stretch the vinyl into a flat sheet (similar to flattening out dough with a rolling pin). Because the film is stretched into shape, it has some degree of memory and therefore is less dimensionally stable than cast vinyl films. This means that when a calendered film is exposed to heat the film will have a tendency to shrink or pull back towards its original form.
Calendered films also tend to be thicker (usually 3.2 to 3.4 mils) than cast films because of the limitations of the calendering process. Unlike casting where a textured or smooth casting sheet is used to produce the film finish, calendering implements a special finish cylinder at the end of the process while the film is still warm. This process is extremely fast and is ideal for bulk production runs. Therefore, color matching is very unattractive on these machines. However, due to its bulk production with high yields, calendered films are relatively inexpensive.
The quality of calendered films can range from economy to intermediate with durability of one to five years. These films generally are not recommended for vehicle applications because they are thicker, less conformable and less durable than cast films.
Some advantages of calendered film are:
Greater production yields equals less cost
- Stiffer/thicker film equals easier handling
- Thickness of film increases resistance to abrasion
So, as you can see, Cast vinyl gives you a high quality look when used as a vehicle wrap, contoured areas or if you want a finish similar to paint. Calendered vinyl will give you a more economical, low cost solution to your short term graphics which you would apply to POP and indoor retail displays. Now that you know the differences between Cast and Calendered vinyl and the applications that best suit them, you can take your knowledge and educate others.