Basf Aktiengesellschaft

Basf Magnetics Gmbh

Milena Melzer

Werner Balz

Norbert Schneider

Helmut Jakusch

August Lehner

Eberhard Koester

Werner Lenz

Albert Kohl

Helmut Kopke

Manfred Ohlinger

Werner Grau

Reinhold Baur

Milan Velic

Heinrich Hartmann

Klaus Schoettle

Peter Rudolf

Jenoe Kovacs

Werner Loch

Gregor Ley

Gregor Brodt

Hermann Roller

Guenter Vaeth

Michael Bobrich

Ria Kress

Wilhelm Sarnecki

Rudolf Bachmann

Horst Fitterer

Friedrich Sommermann

Reinhard Polke

Ernst Ricker

Gunter Schadel

Gunter Vath

Wulf Munzner

Eberhard Koster

Werner Loser

Magnetic recording media consist of a nonmagnetic substrate and at least one magnetizable layer which is firmly applied thereon is based on a magnetic material dispersed in at least one polyureaurethane and a polyurethaneurea (meth)acrylate, the polyurethaneurea (meth)acrylate being obtained by reacting a polyacrylate with a mixture of di- and polyisocyanates and converting the remaining NCO groups into substituted urea groups with aminoalkyltrialkoxysilanes.

Magnetic recording media

In magnetic recording media which have at least one magnetizable layer firmly applied to a nonmagnetic base, the magnetizable layer essentially consists of a magnetic material finely dispersed in an organic polymer binder, a dispersant, a lubricant and other conventional additives.

In magnetic recording media consisting of a non-magnetic base and, bonded on top of this, one or more magnetizable layers based on magnetic material finely dispersed in a polymer binder, a lubricant and further conventional additives, the lubricant used is a triethanolamine esterified with oleic acid.

A process for the production of magnetic recording media by applying a magnetic layer, which consists essentially of magnetic material finely dispersed in organic polymers, to one side of a flexible base, and applying a non-magnetizable backing coating which is free of inorganic solids to that side of the base which is opposite the magnetic layer, wherein the backing coating consists of two or more polymers which are incompatible with one another and have precipitated from a solvent mixture, and magnetic recording media produced by this process.

Production of magnetic recording media possessing a backing coating, and

A magnetic dispersion which can be applied to a non-magnetic base to produce a recording medium is prepared by dispersing a magnetically anisotropic material in a polymer binder and in an organic solvent by a method wherein the magnetically anisotropic material is worked in a jet mill before and/or during dispersing.

Preparation of a magnetic dispersion

Magnetic recording media are produced by preparing a dispersion consisting of finely divided magnetic material, a dispersant, the conventional additives and a solution or a dispersion of a polymeric binder, applying the dispersion in the form of a layer onto a non-magnetizable base, orienting the anisotropic magnetic material by means of a magnetic field and drying the applied layer, by a process in which the dispersant employed is obtained by reacting

Production of magnetic recording media

Magnetic recording media comprise a non-magnetic base which is provided with a magnetic layer which consists of a dispersion of an anisotropic magnetic material in an organic binder which consists essentially of an OH-containing polyurea-urethane binder crosslinked with polyisocyanate. The OH-containing polyurea-urethane is obtained by reacting a polydiol, a diol and a primary or secondary aminoalcohol, and if appropriate a triol, with a diisocyanate.

Magnetic recording media comprising a non-magnetic base which is provided with a magnetic layer which consists essentially of a dispersion of an anisotropic magnetic material in a mixture of an OH-containing polyurea-urethane binder, which is crosslinked with a polyisocyanate, with a physically drying binder.

Magnetic recording media are produced by dispersing timely divided anisotropic magnetic material in a polymeric binder to a non-magnetizable base.

A process for the preparation of acicular ferrimagnetic iron oxides by reducing gamma-iron(III) oxide hydroxide to magnetite, at from 280.degree. to 620.degree. 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.degree. to 450.degree. C., to acicular ferrimagnetic iron oxide of the formula FeO.sub.x, 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.

Preparation of acicular, ferrimagnetic iron oxides

Magnetic recording media are produced by dispersing finely divided anisotropic magnetic material and conventional additives in a solution of a polymeric binder in an organic solvent, or in an aqueous dispersion of a polymeric binder, adding a polymer based on hydrophilic ethylenically unsaturated compounds to the magnetic dispersion, applying a layer of the dispersion to a non-magnetizable base, orienting the anisotropic magnetic material in a magentic field and drying the applied layer.

Magnetic recording media are produced by a method wherein a fluid dispersion of finely divided magnetically anisotropic material in a film-forming binder mixture containing a polyurethane (obtained from a polyester which possesses free hydroxyl groups, and a di- or polyisocyanate) is applied to a non-magnetic base and the magnetic layer is then hardened.

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Ludwigshafen, Germany

Milena Melzer