I've been reading this up at both freaks and SF and there are some very misleading info from SSC. They are right to say PVC is more expensive but technically it's only the process that is. If it's mass produce, PVC is far cheaper then Polystone to manufacture.
He is an article written about different plastic used from figures, toys to statue...
The Materials and the Figures
PVC is used to manufacture figures primarily because it's very cheap when compared to other plastics and it's somewhat resistant. Because PVC is a thermoplastic, it's easy to work with it and it's recyclable.
The PVC used to manufacture scale figures has low quantities of plasticisers so it won't be too rubbery and soft. Good quality PVC is smooth to the touch and has a skin-like appearance which cannot be achieved by using other plastics such as ABS.
PVC is also very fragile and has low resistance against high temperatures and pressure. Those two factors can cause PVC to bend or deform in some other way.
A good example of PVC use (despite the figures) is Nendoroid heads, gashapons, some prize and trading figures, the upper body of figures, etc.
ABS is used primarily for the bases and legs of figures. ABS is a very sturdy plastic and it won't bend, (ABS is the kind of plastic that will break before bending). Because of its hight resistance, ABS is used when manufacturing weight bearing parts.
No good company will make a figure entirely of PVC because as mentioned before, PVC can't handle the it's won't weight without deforming. Some figures manufactured prior to 2007 were made entirely of PVC, which caused them to bend and lean. Like this: View spoiler
Even though ABS is resistant and it won't bend, the very thing that makes it so great can also make it even more fragile than PVC. Depending on how high the fall is, ABS may break, like this: View spoiler Which wouldn't happen to PVC because PVC (the type used to make figures) won't actually break, just bend. But don't worry, good quality ABS won't get damaged very easily and will hardly break because of a fall.
ABS can also very shiny and it has a more plastic appearance than PVC and Vinyl. It is used to make Figma faces and hair, Figmas and Nendoroid joints, scale figure's bases, figure's lower body, LEGO and many other things.
Soft Vinyl is used to manufacture Dollfies and many other figures. Vinyl can be just like PVC (soft and bendable) or like ABS (sturdy but breakable), it varies greatly depending on what it's being used for. Vinyl can also be smooth and have the same skin-like appearance PVC does, but Vinyl is more expensive than PVC and it's a little harder to handle if used to manufacture scale figures, making the manufacture process more complicated and therefore more expensive.
Cold Cast, Polystone and Resin are all very sturdy and fragile. Neither one of them can survive a fall and they break quite easily. They're used to make scale figures, garage kits, larger statues, vases and many other things. They are very resistant against temperature, humidity and they're considerably easier to clean.
Cold Cast and Polystone are similar to porcelain in appearance and resin may have the same appearance as PVC but all the three of them are much, much heavier and expensive.
