in the process for the production of thin , biaxially stretched films from polypropylene , the latter is melted in an extruder and extruded from a slot die over the surface of a take - off roll . the plastic melt cooled on the surface of the take - off roll into an intermediate film is temperature - treated in the region of the take - off roll in a zone and the intermediate film is subsequently biaxially stretched and heat - set in a known way . at a take - off roll temperature t w of between 10 ° c . and 100 ° c ., blowing air of a temperature t l greater than / equal to 30 ° c . is blown onto the film surface on the air side not in contact with the circumferential surface of the take - off roll , the duration for this temperature treatment being at least 1 . 5 seconds .