Basf Aktiengesellschaft

Basf Magnetics Gmbh

Ursula Klein

August Lehner

Werner Lenz

Albert Kohl

Werner Balz

Norbert Schneider

Dieter Schaefer

Rudolf Suettinger

Job-Werner Hartmann

Heinz Stritzinger

Manfred Steuerwald

Guenter Bettinger

Egon Von Gross

Magnetic recording media are obtained by preparing a dispersion of anisotropic magnetic material and additives in a solution of a polymeric binder in an organic solvent, applying the dispersion as a layer to a nonmagnetizable substrate, then orienting the anisotropic magnetic material in a magnetic field and solidifying the applied magnetic layer, and the magnetic layer contains water-repellent polysilica and, if required, a highly viscous polysiloxane.

Magnetic recording media

The orientation ratio (R.sub.f) of a magnetic layer is defined as the ratio of the magnetizations in the playing direction and the crosswise direction. Assuming that the magnetic layer has anisotropy with respect to the transmittance of infrared light, owing to the orientation of the magnetic pigments, infrared light from a source (IR) is passed through a polarizer (P). The linearly polarized light strikes the magnetic recording medium (M), which is conveyed over a transparent support (T). The support and polarizer are adjusted with respect to one another so that a detector (D) is exposed to maximum light intensity, which is proportional to the orientation ratio (R.sub.f).

Measuring method and measuring arrangement for determining the

Magnetic recording media comprising a non-magnetizable flexible base and a firmly adhering magnetic coating based on a dispersion, containing a silane, of a magnetic pigment in a polymeric binder, and a process for their manufacture. The silane is an aminoalkylsilane R.sub.n Si(OR').sub.4-n, wherein n is 1, 2 or 3, R' is alkyl of 1 to 8 carbon atoms and R is aminoalkyl of the formula with one or more primary and/or secondary amino groups and from 3 to 11 carbon atoms. Magnetic recording media comprising a magnetic coating containing such a silane exhibit better abrasion resistance and better electromagnetic properties than comparable coatings.

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Limburgerhof, Germany

Ursula Klein