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:
May. 04, 1976
Filed:
Nov. 06, 1974
Matthias Marx, Bad Duerkheim, DT;
Job-Werner Hartmann, Ludwigshafen, DT;
Werner Ostertag, Oberer-Bergel-Weg, DT;
BASF Aktiengesellschaft, Ludwigahsfen (Rhine), DT;
Abstract
A process for the manufacture of improved magnetic discs by applying a thin layer of a fluid dispersion of magnetic pigments and optional non-magnetic pigments in a binder mixture to a non-magnetic rigid base and curing the magnetic layer which has been applied. The binder consists essentially of from 60 to 90 percent by weight of a solid curable polycondensate of 2,2-bis-(4-hydroxyphenyl)-propane and epichlorohydrin having an epoxide equivalent weight of approximately 400 to 5,000, from 5 to 25 percent by weight of a curable allyloxybenzene-formaldehyde condensate of the resol type with free or alcohol-etherified methylol groups and a molecular weight of less thah 1,000, and from 5 to 30 percent by weight of a curable melamine-formaldehyde condensate with more than two alcohol-etherified methylol groups and a molecular weight of less than 3,000, from 10 to 35 percent by weight of the above epoxy resin being replaced by a reaction product of an epoxy group-containing polycondensate of 2,2-bis-(4-hydroxyphenyl)-propane and epichlorohydrin with the N-methylolamide of a copolymerizable olefinically unsaturated carboxylic acid of 3 to 5 carbon atoms. The magnetic layers thus produced adhere firmly to the base, can be readily ground and polished and are particularly resistant to wear when the magnetic discs are in use.