The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 06, 1977
Filed:
Feb. 09, 1976
Hans-Joerg Hartmann, Breinsheim, DT;
Roland Falk, Achern, DT;
Peter Gawlik, Ludwigshafen, DT;
Werner Balz, Bedford, MA (US);
Karl Uhl, Frankenthal, DT;
Dieter Schaefer, Ludwigshafen, DT;
Herbert Motz, Ludwigshafen, DT;
BASF Aktiengesellschaft, Ludwigshafen (Rhine), DT;
Abstract
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.