| abstract |
PURPOSE: To obtain a polyester film for magnetic recording medium, having low noise level, and excellent handleability, transportability on a deck, and durability for repeated use, by adding silicon oxide subjected to a specific treatment to the polyester at an arbitrary stage in the preparation of polyester. n CONSTITUTION: Water of an aqueous sol of silicon oxide having an average particle diameter of 10W100mμ is replaced with ethylene glycol to obtain an ethylene glycol dispersion containing ≤15wt% of silicon oxide. The dispersion is added to a polyester at an arbitrary stage in the preparation of the polyester in an amount of preferably 0.001W1.0wt%. The obtained polyester composition is formed in the form of sheet, drawn, and heat-set to obtain the objective film. n COPYRIGHT: (C)1984,JPO&Japio |