The adventure continues. There is a live stream from Nighthawkinlight on a further development of the cooling paint.
New sky cooling paint recipe (Patreon livestream no 4)
It's unwatchable in parts (audio,etc.) but starting at
t = 42:23 you get the pertinent info. It's over after 1:10.
Anyways, the improvement is using PLA plastic with ethyl acetate, water and alcohol; with no added pigments. Maybe not as effective as the previous recipe, but from more benign materials and it's sprayable.
I checked
proto-pasta.com/ and they have a clear PLA as well as matte white.
It's not abrasion resistant, so not ready for prime time.