| abstract |
PURPOSE:To reduce noises of a magnetic medium by using as a base on oriented polyethylene terephthalate which has mean surface roughness, maximum projection height, and the number of projections with specific height within specific ranges respectively. CONSTITUTION:Oriented polyethylene terephthalate <=0.005mum mean surface roughness CLA, <=0.05mum maximum projection height PV, and projections whose heights (h) ar greater than 0.27mum and equal to or less than 0.54mum to 0.2 projection/mm.<2> density is prepared by adding an inactive inorganic compound to a film raw material and producing a remaining insoluble catalyst. On the surface of it, a metallic magnetic thin film is provided and on the reverse surface, a lubricant layer of a composition, etc., of polyethylene glycol and polyethylene glycol diglycidylether is formed. |