Polymer Film and Solution Casting Method for Producing Thereof

Abstract

A dope containing TAC is cast onto a belt. When having self-supporting properties, the dope is peeled as a wet film (46) from the belt, and transported into a tenter dryer (60). A preheating is made in an entrance section (80), and a stretching is made in a stretching section (81). In a relaxation section (82), the width of the film was becomes shorter, and in the exit section (83), the width was kept to be uniform and transported from the tenter dryer (60) as a film (61). When a width of the wet film (46) right before the stretching is L1 (mm), a maximum width of the wet film (46) in the stretching is L2 (mm) and a width of the wet film (46) right after the relaxation is L3 (mm), the stretching and relaxation are performed so as to satisfy a following formula, 3<(L2−L3)/L1×100<9

Dependencies are inferred from the claim text.