OZONE, GENERATED AT THE CORONA TREATER, AS AN ADHESION PROMOTER IN EXTRUSION COATING

The trials documented in this paper were run on a pilot coextrusion co ating line at the Tampere University of Technology's Institute of Pape r Converting in Finland. The study was conducted to test the ozonizati on system that was installed in our pilot line to treat the polymer me lt in extrusion coating. The effect of the ozone, generated at the cor ona treater, on adhesion was studied. Ozone was first captured and tra nsported to the nip with separate pipes. It was then led to an air kni fe near the air gap and blown against the polymer melt. The measured a dhesion showed the usefulness of this technique. The following paramet ers were varied to determine the effectiveness of the ozone: substrate , line speed, coating weight, and melt temperature. Results indicated that thicker coating weights and higher melt temperatures improved adh esion values. The corona-generated ozone clearly improved adhesion com pared to corona-treated or untreated samples.