We had static issues on one of our printers with a polyprop material and tried all sorts. In the end we attached Anti-Static Tinsel to the media feed (this is true) so the tinsel was in contact with the media across the width, and then earthed it with a plug into a socket. This made it much better but not perfect.
The main cause of a static problem is the humidity or lack of it where the printer is situated, you could try a humidifier by the printer but this is going to pump water into the atmosphere.
http://www.fraser-antistatic.co.uk/prod … product=31