Patents by Inventor Hildegard Fischer

Hildegard Fischer has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Magnetic coating dispersion
    Patent number: 5660760
    Abstract: In the preparation of dispersions of magnetic pigments, it was found that excellent dispersion stability is achieved when compounds which are selected from the group consisting of quaternary ammonium compounds, guanidines, piperidines, alkylated or ethoxylated amines, diamines, polyamines or mixtures thereof, ethanolic KOH solutions, metal alkoxylates, Grignard compounds and certain metal hydrides are used as codispersants. The compounds are added in an amount of 0.15-4% by weight, based on the magnetic pigment.
    Type: Grant
    Filed: July 29, 1996
    Date of Patent: August 26, 1997
    Assignee: BASF Magnetics GmbH
    Inventors: Attila Vass, Wolf-Dieter Schroeer, Hans-Heinrich Credner, Hildegard Fischer