Flame treatment is the most widely used and cost effective pre-treatment for polyethylene (HDPE, LDPE, UHMW) and polyolefin based plastics prior to polymer bonding or printing. It consists of exposing the surface to be coated to a suitable oxidizing flame during a short period of time (0.2 to 3 sec.).

The resulting change of the surface by creating an oxidized surface greatly improves the liquids ability to wet-out the surface thus creating a strong adhesive bond between the surface and the coating.