Basf Aktiengesellschaft

Dynamit Nobel Aktiengesellschaft

Paul Deigner

Eberhard Koester

Karl Uhl

Roland Falk

Gerd Wunsch

Dieter Schaefer

Werner Steck

Manfred Ohlinger

Dieter Mayer

Herbert Motz

Peter Felleisen

Claus-Dietrich Seiler

Heinz Nestler

Werner Loeser

Friedrich Domas

Werner Stumpfi

Otto Ambros

Helmut Jakusch

Jurgen Amort

Eduard Schoenafinger

Eduard Schonafinger

Klaus Schoettle

Joachim Hack

Werner Grau

Franz-Josef Mueller

Hans Henning Schneehage

Job-Werner Hartmann

Joachim Stabenow

Peter Nagel

Herbert Dietze

Werner Huebner

Manfred Steuerwald

Karl Mahler

Georg Huber

Volker Frank

Hans Hauser

Dieter Graw

Oswald Waidele

Juergen Amort

A transparent window member for a tape cassette, which together with a reel pressure spring, forms a subassembly of the cassette. The reel pressure spring has a U-shaped central portion, the bight of the U being parallel to the plane of the spring arms, and the reel pressure spring having a longitudinal edge with two transverse slits spaced the same as the legs of the U of the central portion of the pressure spring. The central portion may thus be transversely inserted in the longitudinal edge of the window member and it thus forms a locating element for the pressure spring.

Tape cassette, in particular a video tape cassette, and a pressure

A magnetic recording disk comprising a non-magnetic substrate and two or more firmly adhering magnetizable layers applied to one or both sides thereof, the layer located directly on the substrate being magnetically isotropic, while the second layer and any additional layers exhibit orientation of the anisotropic magnetic particles parallel to the substrate and to the envisaged recording direction.

Magnetic recording disk

A device for magnetically orienting the magnetizable particles of magnetic recording media in a preferred direction, which media are obtained by applying a coating of anisotropically magnetic particles finely dispersed in a solution of an organic binder system and conventional additives to a non-magnetic base, and subsequently solidifying the coating, by the action, on the still fluid coating, of the magnetic fields produced by two E-shaped electromagnets arranged symmetrically with respect to, and in mirror-image relationship to, the plane of the said coating.

Device for magnetically orienting the magnetizable particles or magnetic

A magnetic recording medium comprising a non-magnetic base and a magnetizable layer which is applied to at least one side thereof and comprises magnetic particles finely dispersed in a polymeric binder and additives, the surface of the magnetizable layer being provided with a coating of a perfluoropolyether oil mixture as a lubricant.

Rigid magnetic recording disk having perfluoropolyether lubricant

Chromium dioxide magnetic pigments are stabilized against loss of their magnetic properties by treating them, in aqueous and/or alcoholic suspension, with a block copolymer consisting of siloxane units and alkyleneoxy units of 2 to 4 carbon atoms, the alkyleneoxy units being bonded to the polysiloxane radical by a Si--O--C or Si--C group, in an amount of from 1 to 40% by weight based on the chromium dioxide, after which the latter is separated off and dried at from 50.degree. to 200.degree. C. The stabilized chromium dioxide magnetic pigments may be used for the manufacture of magnetic recording media exhibiting improved stability of the magnetic properties under adverse climatic conditions.

Magnetic recording medium and method of stabilization of chromium

A process for the manufacture of wear-resistant magnetic recording media comprising a dimensionally stable base, a thin ferromagnetic metal layer, containing cobalt and/or nickel, firmly bonded thereto and a thin protective layer applied thereon. The protective layer is produced by treating the recording medium in a liquid basic medium, containing gaseous oxygen, for from 1 to 60 minutes at from 5.degree. to 70.degree. C., washing and drying the treated recording medium and then heating it in air at from 170.degree. to 300.degree. C. This method offers a particularly simple way of providing the ferromagnetic layer of the recording medium with a thin but uniform, mechanically stable and wear-resistant protective layer.

Manufacture of magnetic recording media having a wear-resistant surface

An iron oxide pigment having a coating of a silane of the formula

Iron oxide magnetic pigments for the production of magnetic coatings

The invention relates to an improved apparatus for the manufacture of magnetic discs carrying very thin magnetic layers, by applying a fluid dispersion of magnetic materials in a binder mixture to rigid base discs by the spin-coating process. Above the side of the base disc which is to be provided with the magnetic layer, there are arranged means which produce an aerodynamic boundary layer above the discs during rotation of the latter. This avoids the formation of surface irregularities and of coating streaks during production of the layer by spin-coating.

Apparatus for spin coating in the production of thin magnetic layers for

A process and apparatus for the manufacture of magnetic recording media, in which, immediately before the magnetic dispersion is applied to a base, the dispersion is subjected to shear by means of a disc rotatably mounted in a housing, by introducing it at the center of rotation of the disc and forcing it through a gap formed between the face of the disc and the wall of the housing, which gap tapers toward the rim of the disc.

Process for the manufacture of magnetic recording media

Chromium dioxide magnetic pigments can be stabilized against the loss of their magnetic properties by treating them, in alcoholic aqueous suspension, with a silane or a hydrolysis product thereof, so that when the pigment is isolated from the suspension medium the particles bear at least partially hydrolyzed silane on their surfaces, and then drying the magnetic pigment at from 50.degree. to 200.degree. C.

Stabilization of chromium dioxide magnetic pigments

The invention relates to an improved process for the manufacture of magnetic discs carrying very thin magnetic layers, by applying a fluid dispersion of magnetic materials in a binder mixture to rigid base discs by the spin-coating process. Above the side of the base disc which is to be provided with the magnetic layer, there are arranged means which produce an aerodynamic boundary layer above the discs during rotation of the latter. This avoids the formation of surface irregularities and of coating streaks during production of the layer by spin-coating.

Manufacture of magnetic discs

A process for the manufacture of rigid magnetic recording media by depositing a cobalt-containing ferromagnetic metal layer on a non-magnetic metallic base disc provided with a cured layer of binder which does not dissolve or swell in organic solvents and contains non-magnetic pigments, and which has been activated, before deposition of the ferromagnetic layer, by treatment with a solution of a palladium (O) complex in an organic solvent, followed by decomposition of this complex, to prepare it to receive the ferromagnetic metal layer which is produced by electroless deposition.

Process of making a magnetic recording medium

A process for the manufacture of acicular ferromagnetic metal pigments containing iron, having a reduced field strength distribution and a steeper residual magnetization curve, by applying an alkaline earth metal cation and an organic compound having at least one group capable of forming a chelate to appropriate acicular iron oxides and then reducing the treated oxides.

Manufacture of acicular ferromagnetic metal pigments containing iron

A device for manufacturing magnetic recording media in which the magnetic particles in the recording layer are oriented in a preferred direction, the fluid coating applied to the base being subjected to the action of a magnetic field produced in the air gaps between the spaced apart poles of two magnetic circuits, one on each side of the coated face, arranged symmetrically with respect to the plane of the coated base, the edges of the poles adjacent to the coated base terminating in screening elements shaped in such a way that the distance between the surfaces of the screening elements facing the coated base and the coated base itself increases as the screening elements extend away from the edges of the poles. A high degree of magnetic anisotropy in the recording layer can also be obtained when the magnetic circuits are at a relatively large distance from the still fluid magnetic coating.

Growing community of inventors

Weisenheim, Germany

Paul Deigner