摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
A magnetic recording medium in the form of a card having a non-magnetic support with a magnetic coating on one side of the support and a backcoating on the opposite side of the support, which backcoating exhibits improved scratch resistance and adherence to the support and improved frictional characteristics and consists essentially of 20 to 50% by weight of a binder mixture containing 10 to 60% by weight of an elastomeric polyurethane and, incorporated in the binder mixture, a non-magnetic pulverulent mixture of 10 to 40% by weight of conductive carbon powder and 60 to 90% by weight of platelet-shaped and spherical particles.
摘要:
A magnetic recording medium consists of a non-magnetic base, on which the magnetic coating is a layer of a dispersion, containing a lubricant, of a magnetic pigment in a polymeric binder. The lubricant is a block copolymer which contains siloxane units and alkyleneoxy units of 2 to 4 carbon atoms, the alkyleneoxy units being bonded to the polysiloxane radical through a Si--O--C or Si--C group. The use of this lubricant gives a magnetic recording medium which has the advantages of good fluid lubrication and an excellent coefficient of friction which does not vary with time.