| 摘要 |
PURPOSE:To produce a poly(p-phenylene terephthalamide) film having excellent surface accuracy with hardly any thickness unevenness, by cooling a hot cast dope converted into an optically isotropic state on a support surface at a temperature within a specific range and coagulating the dope. CONSTITUTION:(A) A poly(p-phenylene terephthalamide) having preferably >=3.5, preferably >=4.5 inherent viscosity is dissolved in sulfuric acid in >=95wt.%, preferably 98-100wt.% concentration to provide 10-20wt.%, preferably 11-18wt.% polymer concentration and, as necessary, an additive is added to produce (B) an optically isotropic dope, which is then cast on a support surface while keeping the optical anisotropy and converted into an optically isotopic state by moisture absorption and/or heating. (C) The resultant dope is subsequently cooled with water or air to 15-40 deg.C, preferably 20-35 deg.C, then (D) coagulated in a coagulating solution at <=20 deg.C, washed and dried while limiting shrinkage of the formed film to produce the aimed film.
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