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    POLYESTER FILM FOR MAGNETIC RECORDING MEDIUM
    6.
    发明专利
    POLYESTER FILM FOR MAGNETIC RECORDING MEDIUM 失效

    公开(公告)号：JPS615431A

    公开(公告)日：1986-01-11

    申请号：JP12582084

    申请日：1984-06-19

    Applicant: TORAY INDUSTRIES

    Inventor： HARADA SUNAO ,  MIURA YASUKI ,  MOGI MASAHIKO

    IPC: B29D7/00 ,  C08L67/00 ,  G11B5/64 ,  G11B5/73 ,  G11B5/733 ,  G11B5/735

    Abstract: PURPOSE:To obtain the titled polyester film for a magnetic recording medium wherein the deterioration of the electromagnetic characteristics and the generation of dropouts and color noises are prevented by incorporating a specified amt. of inactive inorganic particles so that the area mean diameter and the density of the highest protrusions may be regulated within specified limits. CONSTITUTION:Al is thinly vapor-deposited on the surface of a polyester film used as the supporting body of a magnetic recording medium, and the protruded part which looks black by the observation with a reflection metallurgical microscope is detected. The area mean diameter D1, the number mean diameter D2, and the number N of protrusions are calculated by image processing from the relation between the number Nn of protrusions having surface protrusion diameter Dn and the sum An of the areas of Dn. Meanwhile, the height P of the highest protrusion is measured by a thin-film step- difference meter. When the polyester film contg. 0.005-0.3wt% inactive inorganic particles such as colloidal silica fine particles is manufactured, the area mean diameter D1 is regulated to 0.3-0.12mu, the ratio D1/D2 of the mean diameter D1 to the number mean diameter D2 to 1-2.5, the height of the highest protrusion P to -1X10 unit/mm. . The film is used as a supporting body for a magnetic recording medium having good traveling properties and without the generation of dropouts and color noises.

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