Figurine Science: “PVC”, “Polystone”, “Coldcast”, “ABS”, WTF?

I know many readers of this site collect figurines, action figures and other toys but how many of us here actually know anything about the materials, paints, production process or anything beyond how nice it looks?

Spending a couple of hours doing a wee bit of research on the web, I’ve learnt quite a bit that I’m sure many here would care to know. Hence this new series of articles, titled "Figurine Science" that will talk about the lesser known and perhaps more factual aspects of this hobby.

For the inaugural article on FS, I shall explain the commonly used materials and their properties. I’m sure for the non-science/chemistry students, terms like PVC, ABS probably mean just various types of plastic. But what exactly are these and why is ABS used for bases while PVC for the actual figurine?

Before we start, when we talk figurines, everyone bandies about a few terms. "Resin", "PVC", "Polystone", "Coldcast" mainly. And I am not a chemical engineer so any mistaken information here I would gladly correct if someone in the know points out.

What is "Coldcast"?
Basically, no heat is applied when the material is set in the mould. By mixing two types of liquids, a tough plastic compound is formed.


Cold Cast for the win!!

Polystone
Polystone is the common name for Polyethylene, just another plastic. But there are two main types, High and Low Density. High density is used for the figurines. Polystone offers good resistance to moisture, impact, heat, sunlight, cold and has good rigidity. I mean good compared to PVC. Everything here is compared to PVC.

Polystone distorts of about 80 degrees Celsius. It is not that ductile, lighter than water, and can be moulded, machined, and joined together using welding (difficult to glue). It’s a thermoplastic as well, meaning it can be heated and reshaped and cooled. This is easy to mould and rather durable. The higher heat resistance and rigidity also means figurines do not lean or distort, or worse, start degrading in sunlight. But for this added quality, polystone figurines are more expensive than PVC ones and the selection is a lot less.

Unlike PVC which is more ductile, Polystone does BREAK because of the higher rigidity. So shipping overseas is a bit more of a risk for these. Use EMS at all costs.

And yes, it’s also known as polyethene, the plastic bag. So people who have been fooled by the fancy name, please hang your head in shame.


The bottle cap there is probably polyethylene.

Poly Vinyl Chloride (PVC)
PVC is one of the most common plastics used in the world. It’s quite similar to rubber and the toughness/malleability of PVC is dependant on the plastisers added. More plastisers = more softness, since they straighten out neatly the long macromolecular polymer chains into neat rows. Some figure collectors complain of an oily film after a while and I would think this is due to the plasticisers migrating to the surface of the plastic. Small plasticiser molecules are pretty mobile and after a period of time, they accumulate on the surface to produce a oily crud.

This is also why PVC tends to get a bit crappy and brittle after a long time. Oh yeah these plasticisers are quite toxic too. And if you have a fire at home, dump your figurines at them to extinguish it, since the chlorine produced retards the flame. Btw, some plasticisers are thought to reduce the quality of MAN SPERM.

A very large percentage of the figures sold are made of PVC. From gashapon, trading figures to 1/6s, these are mainly PVCs. Cheap material cost, easy of moulding, ductility (it won’t break much, just bend) are the reasons why it is used.

Never leave them in the sun. Ultraviolet rays produce free radicals on PVC, chlorine free radicals, that combine to form chlorine gas and the material is decomposed. The sun also heats them up and PVC distorts at a temperature of 60 degrees Celsius. Being a thermoplastic, you can actually heat it up and bend it, then cool for it to maintain that shape.

PVC, due to the addition of chlorine atoms which have a pretty high molecular mass compared to C and H, is heavy for a plastic.


Not Junk!! But still pretty cheap.

ABS (Acrylonitrile Butadiene Styrene)
ABS is commonly used for the bases of figurines. It’s pretty recognisable, just think of LEGO blocks. That’s what they are made of. ABS has good impact strength and is not really flexible but rather stiff. These properties plus the glossy surface make it a suitable material for figurine bases. Interestingly, unlike all the above, ABS is not a compound but just a blend of 3 types of plastic.

"ABS is an amorphous thermoplastic blend. The recipe is 15-35% acrylnitrile, 5-30% butadiene and 40-60% styrene. Depending on the blend different properties can be achieved.

Acrylnitrile contributes with thermal and chemical resistence, and the rubberlike butadiene gives ductility and impact strength. Styrene gives the glossy surface and makes the material easily machinable and less expensive." -Designinsite

ABS is more expensive than PVC and is slightly lighter too. Its price is commonly used as the dividing line between common plastics like PVC and more expensive industrial plastics. ABS has a higher distortion temperature at 75 degrees. Its properties are also easily modified by varying the proportions of its components. Its natural colour is an opaque ivory but dyes can be applied.


Tough and strong

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