| 摘要 |
PURPOSE:To provide a method which filters substances evenly at high accuracy, lessens an increase in filtering pressure and lengthens life of a filter, by a method wherein cooling and curing are performed and biaxial orientation and thermal fixation are performed according to necessity after filteration has been performed by the two or more filters mounted is series so that mesh opening becomes small gradually. CONSTITUTION:At the time of melting and extrusion of an aromatic polymer having a ketone group in its molecular chain whose intrinsic viscosity is more than 0.50, the aromatic polymer is cooled and cured after the same has been filtered by two or more filters mounted in series so that mesh opening becomes small gradually. An aromatic polymer film having the ketone group in its molecular chain is manufactured by performing biaxial orientation and thermal fixation according to necessity. The aromatic polymer having the ketone group in the objective molecular chain possesses a repeating unit which is shown by a general expression [I]. In the expression [I], R<1>-R<20> indicates a hydrogen atom or halogen atom or hydrocarbon radical or alkoxy group, X indicates direct binding or oxygen atom or sulfur atom, l indicates an integral number of 0-2, m indicates an integral number of 0-3 and n is either 0 or 1. |
