Originally Posted By: qwertydude
Like I said before, I don't know of any other non-solids based UV inhibitor that wouldn't be required to be listed on the MSDS. And even if you could get minerals to disperse clear, you'd only get so much of them in the mix before they either would build up in cracks and crannies in plastic or at a certain concentration stop being clear. But I suppose you could add certain sunblocking stuff I'm not too familiar with chemically speaking. Some research turns up some promising candidates like octocrylene but you'd have to list it in the MSDS if you did use it. Thus perpetuating my conundrum that if there were non-gras uv blockers we would know. And the gras ones wouldn't work without being obvious. It's a toughy.
But if 100% silicone spray works which I know from experience works very well, perhaps it works on a simple physical level for example the inert silicone helps to block free radicals like ozone, prevents the dissipation of the plasticizers and helps to contain UV damage to just the surface because I definitely know that simple 100% silicone sprays definitely helps protect plastics exposed to the elements. Maybe not 100% UV blocking but that's not the only factor killing exposed plastics. I know mineral oil simply doesn't work as effectively. And door seals are obviously helped by silicone but are rarely exposed to UV.
The claim that lightweight silicon oils is a plasticizer doesn't make too much sense chemically speaking silicone oils are about the most inert material possible. And most plastics simply don't absorb them. Maybe they're claiming some plastics that have a sort of molecular sieve type effect where very light silicones can lubricate enough to seem like a plasticizer but in reality aren't plasticizing, true plasticizers bond in between the polymer molecules to allow movement by allowing stretching between the polymer chains but stays bonded instead of lubricating and allowing the bonds to pass by each other, in effect a shearing action, plasticizers bond and allow movement without the shearing action.
Since it's just lubricating between the bond planes of the molecules giving a temporary softening effect. Such can be the effect with old and degraded plastic where the old plasticizer was removed or rendered inert through UV exposure or ozone oxidation. The silicone can lubricate in between molecules restoring softness at the expense of possible long term durability. This is actually how silicones damage leather too and the most likely scenario for why Armor All is claimed to damage plastics. The Armor All isn't damaging the plastic, the plastic already had the plasticizers rendered inert and water and silicones caused cracking by lubricating the already damaged planes between plastic molecules and the softening effect on a brittle material caused the cracking.
Interesting comments and theory.
An interesting product is vinylex, where the msds does indeed mention the silicones and a uv inhibiting package.
http://www.lexol.com/msds/Lexol Vinylex MSDS.pdf
Zaino is claimed to have their own sunscreen in it, but there is no msds available.
I'm thinking there must be something in there similar to sunscreens, where there is a combination of dispersed solids and uv-reactive chemicals, but you're right, these things should be listed... But hey, look how useless the 303 msds is...
https://www.tapplastics.com/uploads/pdf/MSDS 303 Aerospace Protectant.pdf
The meguiars m40 msds is much better detail-wise.
http://www.meguiars.co.uk/attach/downloads/2826600_uk.pdf
A good patent read.
http://www.google.com/patents/US20120093747