If you buy paint to spray like 2k it comes in a tin, you mix it before putting it in the spray gun - the mix will be Paint, Hardener, Thinners and anything else you want like metal flec etc, you get choices like a hardener can be a fast hardener to reduce flash and drying times, you can also get things like a flexi additive, I don't think it's something you can get in a rattle can not in Halfords anyway, paint shops will mix paint in a spray can you may be able to ask for a flexi additive not sure.
Of course all this is great if you have your own spray gun and compressor and can use it - otherwise you are a bit snookered