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    11.
    发明专利
    未知

    公开(公告)号：DE3224325A1

    公开(公告)日：1984-01-05

    申请号：DE3224325

    申请日：1982-06-30

    Applicant: BASF AG

    Inventor： OHLINGER MANFRED DR ,  VAETH GUENTER ,  RUDOLF PETER DR ,  SARNECKI WILHELM DR ,  JAKUSCH HELMUT DR ,  KOESTER EBERHARD DR ,  MELZER MILENA

    IPC: C01G49/02 ,  C01G49/06 ,  G11B5/706 ,  H01F1/11 ,  B05D5/12 ,  G11B5/62

    Abstract: A process for the preparation of acicular ferrimagnetic iron oxides by reducing gamma-iron(III) oxide hydroxide to magnetite, at from 280 DEG to 620 DEG C., by means of an organic compound which is decomposable at this temperature in the presence of iron oxide, and, optionally, a stream of reducing gas, and, if desired, then oxidizing the magnetite with oxygen-containing gases, at from 150 DEG to 450 DEG C., to acicular ferrimagnetic iron oxide of the formula FeOx, where x is from above 1.33 to 1.50, wherein the organic compound used for the reduction is a non-polar glycerol ester of a fatty acid which is introduced into the aqueous reaction suspension during the preparation of the gamma-iron(III) oxide hydroxide.

    MAGNETIC RECORDING MEDIA
    16.
    发明专利
    MAGNETIC RECORDING MEDIA 未知

    公开(公告)号：CA1026168A

    公开(公告)日：1978-02-14

    申请号：CA197229

    申请日：1974-04-09

    Applicant: BASF AG

    Inventor： VAETH GUENTER ,  BACHMANN RUDOLF ,  SENKPIEL WERNER ,  HARTMANN HANS-JOERG ,  FALK ROLAND ,  MOTZ HERBERT

    IPC: C09D5/23 ,  G11B5/702

    Abstract: The invention relates to magnetic recording media comprising a non-magnetic base and, applied thereto, a firmly adhering magnetic coating based on a finely divided magnetic pigment and a special binder mixture. This binder mixture consists essentially of 20 to 90 percent by weight of an elastomeric polyurethane which is soluble in a volatile organic solvent, is practically free of isocyanate groups and has been obtained from a linear, aliphatic polyester or polyether and a diisocyanate of 6 to 24 carbon atoms, and of 10 to 80 percent by weight of a vinyl chloride copolymer which contains 50 to 90 percent by weight of vinyl chloride units and 10 to 50 percent by weight of units of one or more diesters of maleic acid with an alcohol of 1 to 3 carbon atoms, or of the reaction product of this binder mixture with a polyisocyanate of 6 to 50 carbon atoms. Magnetic coatings containing such a binder mixture are distinguished by improved surface hardness coupled with improved orientability of the magnetic particles, as a result of which such recording media are particularly suitable for modern video- and audio-recording instruments.

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