摘要:
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 reactingA. from 70 to 95 parts by weight of a reaction product ofI. from 0.5 to 1.5 moles of an oxoalcohol of 6 to 20 carbon atoms,II. from 6 to 18 moles of ethylene oxide andIII. from 2 to 10 moles of propylene oxide, withB. from 5 to 30 parts by weight of a polyphosphoric acid having a P.sub.2 O.sub.5 content of from 80 to 88%.
摘要:
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.
摘要:
Described are tape-type magnetic recording media (I) including a non-magnetic substrate (III), at least one film applied to the substrate and, in at least one of these films, an inorganic acicular pigment (II) suitable for use as a supporting pigment, the ratio of the mean length to the mean diameter of the pigment (II) being at least 3 and the mean modulus of elasticity of the films being not less than 15 GPa in the longitudinal direction of the tape-type recording medium (I).
摘要:
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.
摘要:
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.
摘要:
Multilayer magnetic recording medium is suitable for high recording densities and the recording of digital data, has very good electromagnetic recording properties in the entire recording wavelength range and good mechanical properties and possesses a flat frequency response and which has at least one upper magnetic recording layer less than 0.5 &mgr;m thick and at least one lower layer which contains a magnetically soft pigment.
摘要:
Multilayer magnetic recording medium which is suitable for high recording densities and the recording of digital data, has very good electromagnetic recording properties and good surface smoothness and can absorb a large amount of lubricant in the lower layer and has at least one upper magnetic recording layer less than 0.5 μm thick and at least one lower layer which contains a magnetically soft pigment.
摘要:
Ferromagnetic metal particles of substantially iron are prepared by starting from an acicular .alpha.-FeOOH, applying a shape-stabilizing finish to the particle surface, heating at 500.degree.-850.degree. C. and subsequently reducing with gaseous reducing agents at 200.degree.-500.degree. C. to the metal, and starting .alpha.-FeOOH being prepared in the presence of zinc and phosphate ions.