| 摘要 |
<p>A process for producing an aromatic polyamide film, which comprises drawing an undrawn aromatic polyamide film biaxially at a draw ratio of at least 1.5 in a solvent mixture consisting of (a) 5% to 75% by weight of a good solvent of the aromatic polyamide and (b) 25% to 95% by weight of a non-solvent of the aromatic polyamide, and heat treating the drawn film, which contains at least 1% by weight, based on the weight of the film, of a good solvent of said aromatic polyamide, at a temperature of not lower than 150°C.</p><p>An m-phenyleneisophthalamide polymer film having extremely excellent dimensional stability under moist conditions, which film has a density d of from 1.35 to 1.41 g/cm<Sup>3</Sup> and principal refractive indices n<Sub>α</Sub>, n<Sub>β</Sub> and n<Sub>γ</Sub> (n<Sub>α</Sub> > n<Sub>β</Sub>, > n<Sub>γ</Sub>) for D-line of a wavelength of 589 nm satisfying the following formula:<MathDetails id="matha01"><MathText><![CDATA[ <img id="ia01" file="imga0001.tif" wi="36" he="12" img-content="math" img-format="tif" inline="no" /> ]]></MathText></MathDetails></p> |
