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Cast vs. Calendered Vinyl

Learn the dierences and why to use the right vinylin the right application. There huge dierences and

quick read through this article will help youunderstand all the ins and outs of calendered and

cast vinyls.

ByMolly Waters, OEM & Strategic Alliance Specialist, Digital Imaging Avery

Graphics

Whether you are new to the graphics industry or havebeen around for many years, you have most likely heardterms such as; cast, 2 mil, high performance, long-termcalendered, 4 mil, intermediate, short-term and economy

It is safe to say that most people may not know the actual ingredients ormanufacturing processes for these lms. They do, however, know that a short-term or economy lm should not be used for a vehicle wrap and that a cast orhigh-performance lm is overkill for a point-of-purchase (POP) display that willonly be used for six months to one year. This article will explain the dierences

between cast and calendered lms as well as give examples of where each type lm would be used.

What Makes Vinyl VinylLet's begin with a few of the basics on vinyl lms. Most vinyl lms are made from

the same basic raw materials. We begin with polyvinylchloride (PVC) polymer,which is simply basic plastic, and is, by nature, relatively rigid. Other ingredientare then added to the PVC. These ingredients include: plasticizer to make the lexible, pigment to make the desired color, and additives to help achieve speci

properties such as UV absorbers to improve resistance to UV radiation, heat

stabilizers, llers and processing aids. These raw materials can be chosen from http://www.signindustry.com/vinyl/articles/2005-07-01-Avery-CastVsCalendered.php3#story

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wide range of quality levels. Of course, for a lm with limited durability, often thleast expensive raw materials are chosen.

Apart from the type of raw materials that are used at manufacturing, themanufacturing process and the type of plasticizer used create the main

dierences of vinyl lms. Vinyl lms can either be made by calendering or bycasting. Each of these processes renders dierent qualities of lms. Casting

generally results in better quality lms. The grade of plasticizer that is used tomake the lm exible also greatly aects the grade of the lm. Generally for

pressure-sensitive adhesive lms a choice is made between polymeric andmonomeric plasticizers. We won't go into detail on the plasticizers in this article

but for simplicity's sake consider polymeric to be the higher grade and monomerto be the economy grade plasticizer. The combination of these factors greatly

determines the durability of vinyl lms.

Cast FilmsCast lms, also known in the industryas premium, high-performance or 2mil are considered to be a premium

product with excellent durability andconformability characteristics. The

term "cast" refers to themanufacturing process of this type ofvinyl. Making a cast vinyl lm is a lot

like baking a cake. The vinyl beginswith a "recipe" calling for a list of

ingredients known as the formulation.These materials are added to a "bowl"

or mixing churn in a predeterminedorder while mixing at specic speedand for a set amount of time to ensure a complete and consistent mixture. Thisliquid 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 whicallows for the evaporation of solvents. When the solvents are evaporated, a soli

"lm" is left behind. The lm is then wound up in large-diameter rolls forsubsequent adhesive coating. The casting sheet determines the texture of the lm

Because the vinyl is cast on the casting sheet in a relaxed state, this materialoers very good dimensional stability. This process also allows the lm to be verthin (most cast lms are 2 mil), which helps with the conformability of the

product. Material manufacturers recommend the use of cast lms on substratesuch as eets, vehicles, recreational vehicles or boats where the customer wants"paint-like" nish that will last a long time, usually ve to eight years dependin

on how the lm is processed.

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Advantages of cast lms:

Shrinkage is the lowest of all vinyl lms because the "casting sheet," not thlm itself, is pulled through the machine. Since the lm has not had any

stress applied during the manufacturing process it does not try to resume shrink back to its original form.

Durability of cast lms is generally higher than that of other vinyl lms duto the manufacturing method and the raw materials used.

Cast lms can be made very thin which produces a conformable product

that allows application over substrates with rivets, corrugations, andcomplex curves. Also, once applied, this low caliper makes the graphic les

vulnerable to abrasive forces. Cast lms also maintain their color and other properties better than othe

vinyl lms. This results in better performance of pigments and UVabsorbers.

The manufacturing process of cast lms makes it easy to run smallproductions of special colors to match. It is relatively easy to change colo

during production making color matching in small batches possible.

Calendered FilmsLike cast, calendered lm also gets itsname from the manufacturing process.These lms may also be referred to as

intermediate, 4 mil, short-term oreconomy. Calendered vinyl is

formulated with similar raw materialsas cast, except that no solvents are

used. The batch is mixed and heated

to a molten state that resembles pizzadough. Once the lm reaches this

molten state it is extruded through adie and is then fed through a series ofcalendering rolls. These polished steel

rolls progressively squeeze and stretch the vinyl into a at sheet (similar toattening out dough with a rolling pin). Because the lm is stretched into shape,

has some degree of memory and therefore is less dimensionally stable than casvinyl lms. This means that when a calendered lm is exposed to heat the lm w

have a tendency to shrink or pull back towards its original form. Calendered lmalso tend to be thicker (usually 3.2 to 3.4 mils) than cast lms because of thelimitations of the calendering process. Unlike casting where a textured or smootcasting sheet is used to produce the lm nish, calendering implements a speci

nish cylinder at the end of the process while the lm is still warm. This processextremely fast and is ideal for bulk production runs. Therefore, color matching ivery unattractive on these machines. However, due to its bulk production with

high yields, calendered lms are relatively inexpensive.

The quality of calendered lms can range from economy to intermediate with

durability of one to ve years. These lms generally are not recommended forhttp://www.signindustry.com/vinyl/articles/2005-07-01-Avery-CastVsCalendered.php3#story

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vehicle applications because they are thicker, less conformable and less durablthan cast lms.

Advantages of calendered lms:

Greater production yields equals less cost Stier/thicker lm equals easier handling

Thickness of lm increases resistance to abrasionThe chart below lists several attributes of cast and calendered lms and how the

compare to one another.

As with anything else, the nished product is only as good as what you put into This begins with choosing the right vinyl for the job. If you are doing a full vehic

wrap where you want the graphic to conform so that it looks and performs similto paint you should choose a material with these characteristics, which would bcast lm. Calendered lms are ideal for applications that do not require the lm

stretch or conform around contours. Examples of calendered lm uses would boor graphics, wall murals, and point-of-purchase displays.

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