METHOD FOR THE PRODUCTION OF SELF-CLEANING FILMS IN A BLOW MOLDING METHOD

摘要

A surface of the extruded tubular film(3) has raised points which are created either by addition of a material before extrusion of the tube melt or by distribution of a material on the melt surface after extrusion. Raised points are created by addition of components of another melt or particles(10), in particular nanoparticles. Spacing of the raised points or nanoparticles by varying the ratio of the tube radius expansion factor(FR) to longitudinal stretching factor(FZ), i.e. the ratio of circumferential roll speed(V2) at the pinch rolls(8) to initial extrusion velocity(V1) at the die exit. The ratio variation can be from not less than1:4, through several preferred ratios to a final preferred ratio of 1:1.