MATERIAU EN FEUILLE ENDUIT POUR BANDES MAGNETIQUES D'ENREGISTREMENT

摘要

Magnetic recording tape having a backing of biaxially oriented polyethylene terephthalate film containing small amounts of at least two types of structurally dissimilar minute polymeric particles. One type of particle is selected from the class consisting of polypropylene, styrene-acrylonitrile polymer, nylon and incompatible polyesters and the other from the class consisting of polymers of lower olefins. The tape, which has a microscopically irregular, scratch-resistant back free from large protruding particles, is especially adapted for use in instruments and computers, where the resultant dropout incidence is extraordinarily low. A further refinement employs as a backing a two-layer coextruded film, the back layer containing the polymeric particles and the face layer containing no particulate matter and hence being extremely smooth. When the smooth surface of the face layer of such a thin two-layer film is metallized, a mirror-like appearance results; the film can, however, still be handled in roll form.