Vinyls in general are manufactured in one of two ways; "calendering" or "casting".
While at first glance these vinyl's appear similar their differences become apparent over time, and when applied in demanding environments.
The differences are in the manufacturing process and also in the plasticisers and stabilisers used. "Cast" vinyls are manufactured in a less stressed process than used in the manufacture of "calendered" vinyls. Cast films have the resin poured to form an extremely thin layer onto a very smooth surface before going through curing ovens. Cast vinyl generally have better dimensional stability, colour pigmentation, uv stability, and higher gloss levels.
"Calendered" vinyls are manufactured differently, using an "extruded" or "rolled" process which is more stressful on the PVC resulting in less dimensional stability in the direction it was rolled, it is however a lot cheaper than cast films. Calendered vinyls are either 'monomeric' or 'polymeric' dependent on the plasticiser's molecular structure.
"Monomeric" vinyls use plasticisers with a smaller molecule size so there is more molecular migration than in polymerics and will therefore have more effect on the adhesive and laminates used. These shorter chains of molecules also make the vinyl brittle when used in more demanding environmental conditions over time and resulting in shrinkage or "pulling".
"Polymeric" vinyls have longer molecular chains and larger molecules allowing less migration from the vinyl and so have less effect on the adhesive and will aid better longevity, flexibility and additional film stability with less shrinkage.
It is possible to buy monomeric or polymeric vinyls in either "calendered" or "cast" though it is pretty rare to get a monomeric cast film and most usually a cast film is a polymeric type of vinyl. The type of plasticisers used will have a noticeable effect on digital printing and how conformable the vinyl is. Polymerics are generally a lot better to print on than monomerics due to the surface plasticisers.
Calendered vinyls are less dimensionally stable and may shrink due to the mechanical manufacturing process whereby the PVC retains 'memory' of it's original form and will attempt to return to this original form.
PVC is naturally a rigid material so 'plasticisers' are added to soften the vinyl for practical use, other additives are 'stabilisers' in the vinyl to protect against the effects of heat, UV light and also to create coloured vinyls.
Two types of calendering are currently available; 'monomeric' and 'polymeric' - differentiated by the two types of plasticisers used in their manufacture. It is worth noting that these two types of calendered vinyls perform slightly differently in one direction than the other (i.e.: in machine direction and cross machine direction).
Monomeric vinyls contain plasticisers which use short-chain chemical bonds so don't bind into the film as efficiently so will more easily migrate from the film leaving it brittle over time. Monomeric films are suitable for most internal applications and selective short-term external applications, are generally quite stiff so can be harder on blade wear and are barely conformable over contours so are recommended for flat-sided applications only.
RECOMMENDED USE: Interior work and short term external applications where life span is expected to be 2, 3 and 3-5 years and are usually 75-85 microns thick.
Polymeric vinyls, sometimes known as 'stabilised films' or 'extended life films' contain long-chain plasticisers which allow them to bind into the film more efficiently, thus reducing the migratory effect. These films are generally less prone to shrinkage, typically 50% less than a Monomeric vinyl.
Polymerics feel softer and in general have a longer outdoor life expectancy compared to monomerics.
These films are primarily available in a gloss finish, although translucent and matt finishes are also obtainable.
They are suitable for most external applications, but conformability over complex contours is somewhat limited.
RECOMMENDED USE: Interior work and intermediate external applications where cast films are not an option. Polymeric vinyls are ideal for flat or slightly curved surfaces, with a 5-7 years and 8+ years life span and are most usually 70-75 microns thick.
Cast vinyls are the choice where dimensionally stable applications are required.
The liquified resin is coated onto a highly polished substrate i.e. casting paper, to produce an extremely thin film of vinyl. Due to the lack of mechanical force being used cast films do not retain 'memory' as with calendered vinyls, consequently shrinkage is minimal (typically 50% less than polymeric films).
Cast films are generally very soft to handle and are easier to cut, weed and apply than calendered alternatives.
Cast films are primarily available in a high gloss finish and are the ultimate in terms of conformability over complex contours i.e. rivets, corrugations etc. and are the preferred option for the most extreme exterior applications and vehicle wraps.
All the ingredients used in the production of cast vinyl are of the best quality so performance is superior in terms of temperature ranges, colorfastness etc. is generally better than that of calendered films.
Cast films also perform equally well in both directions, i.e. in machine and cross machine direction.
RECOMMENDED USE: Due to a cast films long life, stability and quality it is suitable for most types of work where there is any doubt as to which type of vinyl is best to use, and is a premium vinyl for interior and external applications. Normally cast films are 8-10 year films and are 50-60 microns thick, soft, thin and flexible so are ideal for all types of vehicle wraps.