I've seen some ski goggle visors out there that have a similar shape to the security visor. Or you could always try vacuum forming if you want an even more accurate shape. I haven't done too much research into vacuum forming myself but I know there's plenty of info out there on how to do it
Vacuforming is a good way to go, however you'll need a machine to be able to do it properly. After that, you can dye it and/or add reflective tinting - there's quite a few resources out there on how to do that. Never made a visor myself, so I can't give my expertise.