making printed ink on plastic permanent?

Hi, I have transparent plastic and I want to print on it, which works but when the plastic touches something the ink gets wiped out. It doesn't seem to dry, I left it over night and it was still the same. How can I make it permanent and keeping it as transparent as it is? I can't just add normal varnish because it would also wipe out the ink. Will hairspray work(I don't have it in my home right now), or will it make the surface of the plastic uneven so it's less transparent? Are there other ways? thanks