Biaxial orientierte Folie und magnetisches Aufzeichnungsmedium das diese als Basisfolie enthält

摘要

A biaxially oriented film made from a wholly aromatic polyamide produced by an acid chloride process, which contains at least one member of inorganic particles having an average particle diameter of 5 to 2,000 nm and selected from the group consisting of hydroxides, carbonates and bicarbonates of metals of groups Ia and IIa of the periodic table. The inorganic particles is derived from inorganic particles which are added as a neutralizing agent to a reaction system to neutralize hydrogen chloride by-produced by the acid chloride reaction and its content corresponds to an excess portion added to the reaction system over the amount required for neutralizing the hydrogen chloride stoichiometrically. The film is useful as a base film for a magnetic recording medium, such as a coated, a multi-layer coated, or a thin metal film high-density magnetic recording medium.