Basf Aktiengesellschaft

Dieter Schaefer

Herbert Motz

Paul Deigner

Roland Falk

Eberhard Koester

Karl Uhl

Dieter Mayer

Werner Balz

Joachim Hack

Hans-Joerg Hartmann

Peter Felleisen

Claus-Dietrich Seiler

Manfred Ohlinger

Helmut Jakusch

Werner Ostertag

Jenoe Kovacs

Heinz Nestler

Eduard Schoenafinger

Ingolf Buethe

Job-Werner Hartmann

Heinz Stritzinger

Werner Huebner

Manfred Steuerwald

Udo Boehm

Hans Joerg Hartmann

Werner Stumpfi

Otto Ambros

Job Werner Hartmann

Gustav Loewenberg

Ursula Klein

Hilmar Lechner

Rudolf Sand

Egon Von Gross

Adam Weber

Peter Gawlik

Juergen Amort

In a container for a plurality of disk-shaped articles, the partly opened base portion possessing receiving grooves consists of two substantially identical parts which can be assembled, and two further, substantially identical cover parts which at least partially close the openings, and means are provided for disengageably locking the parts of the base portion to the cover parts. Interlocking stacking means are used for stacking a plurality of the base parts, with or without cover parts. The container of the parts of the base portion are useful for any transportation and archiving purposes during production of the articles or by their end users.

Container for a plurality of disk-shaped articles and container part

Layer-type magnetic recording media are produced by applying a dispersion of a magnetically anisotropic material in a binder solution onto a flexible plastic base provided with an adhesion-promoting layer and then solidifying the magnetic layer, by a method in which the adhesion-promoting layer consists of a radiation-curable aqueous dispersion of a polymer.

Production of magnetic recording media

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

A process for the manufacture of magnetic recording media by dispersing a mixture of particulate anisotropic magnetic material and additives in a solution of a polymeric binder in an organic solvent, compressing and then releasing the pressure on the dispersion, thereafter applying a layer of the dispersion to a non-magnetizable base, orienting the anisotropic magnetic material by means of a magnetic field, and drying the coating.

Manufacture of magnetic recording media

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

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

Magnetic recording media comprising a base and, applied thereto, at least one firmly adhering magnetic layer based on magnetic particles dispersed in a mixture of organic binders, wherein at least the uppermost magnetic layer additionally contains non-magnetic particles of precipitated silica having a primary particle diameter of from 0.02 to 0.1.mu., a secondary particle diameter of from 2 to 4.mu. and a pH of from 5 to 8. As a result of the incorporation of such a precipitated silica into the magnetic layer, the coefficient of friction between the latter and metals remains uniformly low even after prolonged use, and no stick-slip motion occurs.

Magnetic recording media having a low coefficient of friction

Magnetic recording media consisting of a non-magnetic base and, applied thereto, a firmly adhering magnetic coating based on finely divided magnetic pigment dispersed in organic binders, which coating contains, according to the invention, salts of long-chain basic polyaminoamides with high molecular weight organic acid esters. Such magnetic recording media exhibit improved mechanical resistance and improved adhesion of the coating to the base, coupled with advantageous electromagnetic properties.

Magnetic recording media of improved mechanical resistance

The invention relates to a process for the manufacture of improved magnetic discs by applying a thin layer of a liquid dispersion of magnetic pigments and optionally further, non-magnetic, pigments in a binder mixture to a non-magnetic rigid base, and curing the magnetic coating which has been applied. The binder used is a mixture of polycondensates comprising 60 to 70% by weight of a solid curable polycondensate of 2,2-bis(4-hydroxyphenyl)-propane and epichlorohydrin having an epoxy equivalent weight from about 400 to 2,500 and a melting point from about 50.degree. to 150.degree. C, 10 to 30% by weight of a curable allyloxybenzene-formaldehyde condensate of the resol type with free methylol groups or with methylol groups etherified with a lower alcohol, and having a molecular weight of less than 1,000, and 10 to 30% by weight of a curable melamine-formaldehyde condensate with more than two methylol groups etherified with n-butanol or iso-butanol, and having a molecular weight of less than 2,500. A magnetic dispersion using such a binder allows the application of a firmly adhering magnetic coating, even in thicknesses of less than 4 .mu., to aluminum discs or pre-coated aluminum discs, and the magnetic coating produced has high resistance to mechanical wear.

Magnetic recording discs

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.

Device for the magnetic orientation of magnetic recording media

A process and apparatus for the manufacture of magnetic discs in which the preferred direction of particle orientation is parallel to the plane of the disc and tangential to its circumference. The base discs coated with the still fluid magnetic dispersion, are introduced into a zone of magnetic flux bounded by conductors, the conducting boundary being so arranged that the current flow on one side of the base disc runs radially outwards and on the other side runs radially inwards.

Process and apparatus for the manufacture of rigid magnetic discs

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.

Magnetic recording media

The invention relates to magnetic discs in which first a non-magnetic intermediate layer and then the magnetic coating are applied by conventional methods to an aluminum disc. The intermediate layer applied to the non-magnetic metallic carrier disc is a hard non-magnetic coating which can be polished and which consists of a dispersion of a pulverulent mixture of finely divided inorganic non-magnetic pigments having a Mohs' hardness of at least 7 in a binder which can be cured and which provides firm cohesion of the pigment particles and good adhesion thereof to the non-magnetic base disc, the pigment mixture containing at least 3 percent by weight of corundum powder having a particle size of from about 1 to 20.mu.u. Magnetic discs with very thin magnetic coatings which possess good magnetic and mechanical properties and whose thickness varies only minimally are thus produced in a simple manner.

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Lindenberg, Germany

Dieter Schaefer