An oversimplification, but pleather peels and cracks from drying out and debonding or delaminating from the surface it’s adhered to.
Well, I'd say it is no oversimplification, but spot-on.
It is not just UV exposure that does this, but also other factors like temperature, humidity (partially why Hot Toys puts desiccant packs in the box with the figure), dust and oils in the air, and surface soiling.
Among seasoned collectors, UV exposure is no longer a problem to be reckoned with. Yet, pleather dies out even in boxed figs w/ desiccant, where humidity and pollution are very low.
It would be oxigen, mostly and mainly, what should be avoided at all costs.
How? Impossible in practical use, possible when in storage: those cheap vacuum thingies and bags used to keep food good for longer stretches. That might help. Very little oxidization / drying out, maybe.
Surface soiling might have an impact (avoided by using gloves or washing hands), but for the most part, pleather's plasticky finish could be quite impermeable. Pleather can die out even in slightly handled figs.
Air polution's effect, when figures are kept in enclosed environments, inside rooms insidenhpises might be negligible.
Yes, products like 303 help to prevent fading and cracking primarily by acting as a UV resistant surface protectant. But that is not all they do. They also restore luster, depth of color, and shine to the surface which in turn keeps the material healthy, so to speak.
To me, that sounds too esoteric. Luster? Depth? Healthy?
How exactly does all that happen?
eg. Tires that are properly black from being conditioned will last longer than tires that are gray and dried out which in turn leads them to being more susceptible to cracking from UV damage and heat. So as an aside, everyone should always put a quality water based dressing on their tires to help make them last longer.
Is 303 the same substance you mention as being used on tires?
Anyway, I can imagine the outer layers of a tire's rubber absorving some stuff that
protects it. Also pleather's cloth backer, but the plasticky surface, or the glue
that keeps everything together......
Good surface treatment products like 303 can also be anti-static and help to resist smudges, dust, and soiling, further protecting the material.
Anti-static properties only affect dust collection, which I'd say is not a pleather killer.
I’ve tested numerous interior protectants for automotive use and 303 has been a good product overall. I typically recommend 303 to 1:6 collectors because it’s the highest quality vinyl, rubber, and plastic protectant at its price point, which is relatively low. And other people have tested it on their figures as well.
Because car interiors can do a lot if UV exposure, but again, how the front, vsible, plasticky side of those materials
absorb ANYTHING, is beyond me yet. Best guess: a film is formed on the material to be protected, which will eventually
evaporate or wear off by touch.
The only caveat is that 303 is not intended to be used on fabric, so care must be taken when applying.
