METHOD AND APPARATUS FOR LONGITUDINALLY STRETCHING A SUBSTANTIALLY AMORPHOUS POLYETHYLENE TEREPHTHALATE FILM

摘要

Method and apparatus for longitudinally stretching a substantially amorphous polyethylene terephthalate film. Method and device for longitudinally stretching film, wherein there is a strict separation of the tensioning operation from the heating and the cooling operations of the film, and a symmetric heating and cooling of the film, and wherein the heating of the film occurs in two stages, namely a preheating by means of diffused IR-radiation, and a line heating by means of bundled IR-radiation.