Aromatic polyamide-type films
AssigneeToray Industries, Inc.
InventorsToshiyuki Asakura, Masaaki Itoga, Takeshi Hayakawa, Masamitu Tanimura
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Abstract
Aromatic polyamide-hydrazide films, consisting of p-benzamide p-phenylene terephthalamide and/or terephthaloyl hydrazide recurring units, as major chain constituents, are removed from inorganic residue by an aqueous mixture which dissolves or swells the films, and are heated up to their crystallization temperatures in tension, giving rise to high tensile strength and modulus, good hygroscopic dimensional stability and excellent electrical insulation properties.
Claims11
An aromatic polyamide-type film, substantially consisting of a member of the group consisting of at least one of p-benzamide, p-phenylene terephthalamide and terephthaloyl hydrazide recurring units as essential chain constituents, which constituents comprise at least about 70 mol % of the entire film, and which have an inherent viscosity of more than 1.0 at 25.degree. C, a density of more than 1.41 g/cm.sup.3 at 25.degree. C and 0% relative humidity and a planar orientation coefficient of larger than 0.65, obtained by the X-ray pole figure method, said film being substantially free of organic solvent and inorganic ionic compounds, and having been prepared by heating to the polymer crystallization temperatures while preventing free shrinkage in the machine direction and in the transverse direction.
The method of manufacturing aromatic polyamide-type films, consisting of at least one member selected from the group consisting of p-benzamide, p-phenylene terephthalamide and terephthaloyl hydrazide recurring units as essential chain constituents, which constituents comprise at least about 70 mol % of the entire film, comprising the removal of organic solvents and inorganic compounds from the polymer films, and heating to their crystallization temperatures, while preventing free shrinkage in the machine and in the transverse direction, so that the treated films have a density of more than 1.41 g/cm.sup.3 at 25.degree. C and 0% relative humidity, an inherent viscosity of more than 1.0 at 25.degree. C and a planar orientation coefficient of more than 0.65, obtained by the X-ray pole figure method.
Dependencies are inferred from the claim text.