Vinyl Film: Cast versus Calendered

Unless you're in the sign industry or wrap cars for a living, it's unlikely that you've ever thought about the difference between cast and calendered vinyl films. And, to be honest, why would you? For most people, all that really matters is that they get a sheet of vinyl that will work for what they want it to do. But, with the rapidly expanding online market for vinyl wraps, heat transfer vinyl and crafting vinyl favor personal and hobby use, it has become incredibly important to know the difference. Cast and calendered film begin as similar materials, but their manufacturing processes produce very different results. Cast film is thinner and more long lasting while calendered film is thicker, stiffer and less expensive. In other words, you don't want to end up with a roll of ORACAL 651 Intermediate when you are looking to wrap your car's hood or a sheet of 1080 Anthracite for cutting small lettering — suffice it to say that using cast and calendered films for the wrong purposes can lead to headaches and waste your hard earned time and money.

At Rvinyl, we're only happy if you're happy with our products which is why it's absolutely crucial that you understand what kind of vinyl you're getting and how you can expect it to perform. In the following, we'll take a look at how cast vinyl films are made in comparison to so-called calendered films and the performance that results from their unique manufacturing processes.

A Tale of Two Vinyls

Without belaboring the point it's important to at least get a basic understanding of the two main types of vinyl film on the market. Both cast and calendared vinyl share polyvinylchloride (PVC) polymer as their primary ingredient. PVC is just a basic plastic, and is, by its nature pretty rigid. The next step in the process is the addition of plasticizers which make the film flexible, dyes and pigments to make the desired color and additives which resist UV radiation, act as heat stabilizers and add special properties such as reflectivity, etc. Naturally, there can be quite a range of quality in the additives used and much of this will depend on the projected end use of the film.

Aside from the quality of raw materials used for manufacturing, the manufacturing process itself and the kind of plasticizer used therein are responsible for the main differences between cast and calendared vinyl films. In general, casting generally results in higher quality films such as wrapping films like Avery SW900 and 3M™ 1080 films. The type of plasticizer used to make the film more flexible also has a great effect on the properties of the film. Generally for PSA films there is a choice between polymeric and monomeric plasticizers. For the sake of simplicity, polymeric plasticizers can be thought of as higher grade while monomerics are the economy grade plasticizers. The combination of production method and grade of plasticizer is the prime determinant in the durability performance of vinyl films.

Cast Vinyl Film

Cast vinyl is the type of vinyl used in vehicle wrapping precisely because it is long lasting and thinner than calendared films. The term cast refers to the manufacturing method used in making of this type of vinyl. Cast vinyls begin their lives as little more than a thick, plastic paint. The PVC, plasticizers and pigments are mixed together at a predetermined rate of speed for a set duration in order to ensure a consistent mixture. This liquefied mix, known as organosol, is then metered (or cast) onto a moving matrix known as the casting sheet. Next, it is processed through a series of ovens which allows for the complete evaporation of solvents. When the solvents have evaporated, a solid film is all that is left behind. The film is then rolled onto large-diameter cores for additional adhesive coating. The casting sheet is what determines the texture of the film. This type of film is recommended when the customer wants a painted-look finish that will last, with average lifetimes being from five to twelve years.

Benefits of Cast Vinyl

  • The film has a minimum of shrinkage compared to calendared films due to the fact that the sheet rather than the film itself, is pulled through.
  • Higher-durability due to the quality of plasticizers and raw materials used.
  • Cast films can be made in much thinner gauges so they conform to substrates with corrugations and complex curves.
  • Cast films maintain their color and other properties better than other calendered films.
  • The less intensive process used means it's cost-effective to do small production runs of special colors giving a wider range of colors to you.

Calendered Vinyl Film

Like cast vinyl, calendered film also takes its name from the manufacturing process. The manufacture of calendered film is similar to mixing and rolling out a fresh pasta although the formulation uses almost identical raw materials as cast. The ingredients are mixed and then kneaded and expelled by the extruder like sheets of lasagna. Gigantic, heated, steel rollers form the vinyl into a thin sheet in a process called calendering. The first steps are the mixing and extrusion. In these initial steps, all of the raw materials are mixed together based on the specific formulation. Improved formulations and the use of new pigments has lead to increased color options for calendered film although they still pale in comparison to cast films.

During the extrusion process the fine powder mix (dry blend) is fused together into a lump, called the melt. The next step, also called milling, consists of two counter-rotating rollers, which are then heated to temperatures of up to 350 degrees Fahrenheit. The melt is pulled into the rollers and flattened due to the increasing pressure and temperature applied by the mill rollers. As it passes through a number of rollers, the film becomes thinner and wider according to the type of film being made. Once the film has reached its final dimensions, it needs to be cooled down and transported to the last process stage of winding. The quality of calendered films can range from economy or intermediate, which use a monomeric plasticizer, to a high-grade which would use a polymeric plasticizer.

Benefits of Calendered Vinyl

  • Stiffer and thicker film makes for easier handling
  • Great performance on flat, simple and moderate curves
  • More economical than cast film
  • Calendered films have a higher resistance to abrasion

How to Choose the Right Type of Vinyl

Even though you might now know the differences between cast and calendered vinyl film, you may still be wondering which you should choose for your specific project. Although we will get into the minutiae shortly, one good rule of thumb was given by our friends at Arlon. In short, when you're buying a vinyl film you wan to consider how often it will be exposed to direct sunlight. In other words, "time in the sun is never your friend when you happen to be a material that was chosen for cost rather than durability." We've all seen cracked and faded signs and decals but, more often than not this isn't so much the quality of the vinyl's fault as the fault of an installer who chose the wrong kind of film. Removing cracked or discolored vinyl film is no joke and can often times cost as much or more than the labor and materials of initial application so choose well and don't be penny wise and pound foolish.

Uses of Cast Vinyl Film

As we've mentioned above, cast films are pretty much considered the industry premium. If you skipped the above, the long and the short of it is that the casting process produces a thin film—usually 1 to 2 mil thick. By casting film on a sheet, the film stays in a more relaxed state, resulting in a durable, flexible, conformable and dimensionally stable film that retains color well. As a result, cast films are ideal for complex surfaces such as vehicles and where a smooth finished look is expected. In addition, because these films can be produced in small batches, you get a much wider variety of colors and finishes than are available with calendered films. One caveat when dealing with cast films is that they usually feature an air release adhesive for wrapping which makes them excel at wraps but less than ideal for decals or lettering.

Recommended Uses for Cast Vinyl

  • Vehicle wraps
  • Architectural wraps
  • Smartphone (iPhone, Android) wraps

Recommended Brands of Cast Film

Uses of Calendered Vinyl Film

Calendered films are perfect for applications that don't require the film to stretch or conform around contours and complex curves. Although this might seem like a bad thing, if you've ever tried to make a graphic with cast film that features air-egress liners you'll know that it's not a good idea since the transfer tape that is intended to keep the spacing won't stick to the liner. In addition, calendered films are perfect for making prespaced lettering or graphics because they are thicker and won't stretch out of shape.

Recommended Uses for Calendered Vinyl

  • Sun Shade Visors
  • Floor Graphics
  • Prespaced Lettering
  • Window Decals

Recommended Brands of Calendered Film

Choose the Vinyl Film That's Right for You

So you've made it to the end of the article and still don't know what you need, have you? Well, luckily for you, we're here to help. Simply chat with us during business hours or drop us a line by email and we will be happy to help you pick out the right type of vinyl for you.