| 摘要 |
PURPOSE:To obtain a film having a specific moisture absorption and excellent dimensional stability, by drying the dope of poly-p-phenylene terephthalic amide in specific conditions in casting optically anisotropic dope of poly-p-phenylene terephthalic amide on a support surface, transforming the dope into a dope having optical isotropy and solidifying, cleaning and drying the dope. CONSTITUTION:Poly-p-phenylene terephthalic amide having >=3.5 logarithmic viscosity is prepared in form of optically anisotropic dope using sulfuric acid having >=95wt.% concentration as a solvent. The dope is cast on a support surface, transformed into a dope having optical isotropy and then solidified, cleaned and dried at temperature T1 of >=350 deg.C without shrinking or dried without shrinking at arbitrary temperature and heat-treated at temperature T1 of >=350 deg.C without shrinking and then heat-treated at temperature T2 satisfying the equation expressed by the formula under tension of 0-0.8kg/mm<2> to provide the film having (5+ or -10)X10<-6>mm/mm/ deg.C coefficient of thermal expansion, <=0.1 thermal shrinkage at 250 deg.C, <=30X10<-6>mm/mm/%RH coefficient of humid expansion at 25 deg.C and <=2.5wt.% moisture absorption at 25 deg.C in 65%RH. |
