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    MANUFACTURE OF FLEXIBLE MAGNETIC RECORDING MEDIA
    2.
    发明专利
    MANUFACTURE OF FLEXIBLE MAGNETIC RECORDING MEDIA 未知

    公开(公告)号：CA995068A

    公开(公告)日：1976-08-17

    申请号：CA179850

    申请日：1973-08-28

    Applicant: BASF AG

    Inventor： HARTMANN JOB W ,  HARTMANN HANS J ,  ROLLER HERMANN ,  STRITZINGER HEINZ ,  FALK ROLAND

    IPC: C09D5/23 ,  G11B5/702 ,  G11B5/738

    Abstract: 1445152 Magnetic coating BASF AG 29 Aug 1973 [30 Aug 1972] 40667/73 Heading B2E A flexible magnetic recording media is produced 'by applying a 0.05-1.5 microns thick intermediate coating to a dimensionally stable plastics film which acts as base and subsequently applying a layer of a fluid magnetic dispersion consisting of a finely divided magnetically anisolbropic magnetic pigment, an organic binder which does not cross-link during the dispersion of the magnetic pigment, is free from isocyanate groups and is dissolved in a volatile organic solvent which does not react with isocyanate groups and, optionally a dispersing agent and other conventional additives, orienting the magnetic particles in a magnetic field, drying the magnetic coating and optionally subjecting the magnetic coating to a surface treatment, the intermediate coating comprising a vinylidene chloride copolymer which does not react with isocyanate groups containing 5-70% by weight of a scluble polyisocyanate, and the binder and/or dispersing agent for the magnetic coating containing groups which react with isocyanate groups. The base may be polyethylene terephthalate film. Suitable vinylidene chloride copolymers are copolymers containing at least 70% of vinylidene chloride units, and suitable comonomers are methyl methacrylate, dimethyl maleate, methacrylonitrile and especially acrylonitrile. The magnetic pigments in the magnetic coating may be gamma-iron oxide, magnetite, ferromagnetic chromium dioxide, fenromagnetic metals and metal alloys. Suitable binders for the magnetic coating are vinyl chloride-vinyl ester copolymers, vinylidene chloride-acrylonitrile copolymers, copolyamides, soluble thermoplastic polyester-urethanes, polyvinyl formals and mixtures thereof. Hydroxyl groups or other groups which react with isocyanate groups may be provided in the binder by using copolymers of 50-80% vinyl chloride and 20-50% vinyl esters into which 4-20% by weight of vinyl alcohol units have been introduced by partial hydrolysis. Dispersing agents having groups that react with isocyanate groups mentioned are oleic ethanolamide, isostearic acid, stearic acid, oleic acid, lecithin. Other additives mentioned are lubricants, e.g. metal soaps, fatty acids, waxes, silicon oils, conductive carbon, talc, silicates. The oriented and dried magnetic coatings may be calendered and the coating webs then slit in the longitudinal direction.

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