Prodn. of biaxially stretched plastic film without sticking

摘要

The prodn. of biaxially stretched film from a plastic melt comprises extruding the melt through a sheet die to form a melt film, cooling to a pre-film on a draw-off roller (3), passing over a take-off roller (4) with a roughened surface, then biaxially stretching and heat-fixing. Roller (4) has a definite surface roughness and an operating temp. of 23-110 deg. C. Also claimed is an appts. for this process with the above components, the take-off roller (4) having a given surface roughness with an average peak-to-valley height of Ra = 0.3-1.1 microns, measured with a cut-off of 0.8 mm.