| 摘要 |
A method for the production of biaxially molecularly oriented polymeric film, wherein the flatness of the film is improved by subjecting the film preferably immediately after its heat-setting to a longitudinal tension that is at least three times higher than the normal film transport tension in the production process. Preferably, said higher longitudinal tension is at least 100 kp/sq.cm. The film may be subjected also between its longitudinal stretching and its heat-setting to said at least three times higher longitudinal tension. The temperature of the film during said treatment at increased longitudinal tension is between room temperature and the second order transition temperature of the film. |
