| 摘要 |
PURPOSE:To provide the titled film having high crystallinity and high plane orientation and suitable for an electronic part for high density circuit, having extremely excellent dimensional stability with moisture, by specifying the density and the principal refractive indices of D-lines at respective specific values. CONSTITUTION:A composition obtained by compounding preferably a poly(m- phenyleneisophthalamide) polymer, an amide solvent such as N,N-dimethyl-acetamide, and a solubilization assistant composed of calcium chloride, is introduced into a multi-stage aqueous coagulation bath through the T-die of an extruder to effect the wet film-forming. The obtained water-containing undrawn film is drawn in wet state at an areal draw ratio of 2.5-15, and heat-treated in a system containing a plasticizer to obtain the objective film having a film density (d g/cm<3>) of 1.35-1.41 and a principal refractive indices of D-line (589nm wavelength) satisfying the formula (provided that nalpha>nbeta>ngamma). |
