>>1432810Doesnt take an expert to know that the first 3 batman movie suits including the masks were made from latex.
Ontop of that the only way to make that with an injection mold would be to sculpt it, mold it, then place the head cast in the mold and inject whatever material you were using whether it be silicone or latex. Either way, thats making ALOT more work for the cosplayer, on top of that there is a large chance it would fit wrong due to misplacement of the head cast.