| 摘要 |
A method and device for longitudinally stretching polymeric film, characterized by the strict isolation of the tensioning operation from the heating and the cooling operations of the film, by the symmetrical heating and cooling of the film, and by carrying out the heating of the film in two stages, namely preheating by means of diffused IR-radiation, and a full heating, preferably along a line, by means of bundled IR-radiation. The film stretched in this manner meets high standards of flatness and surface quality, and is subject to minimum waste losses and is especially useful in the photographic field.
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