Patents by Inventor Karl E. Helf

Karl E. Helf 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).

  • Raw material and film prepared therefrom, having improved electrical properties
    Patent number: 4910639
    Abstract: A biaxially-oriented film, suitable for use as an electrically insulating film, is disclosed. The film is composed of a highly-pure electrical film raw material based on polyolefins, in particular propylene polymers, and contains carbonate particles as a neutralizing agent. The carbonate particles preferably have an absolute particle size of less than 10 micrometers, a mean particle diameter of less than 0.1 micrometer, a specific surface area of more than 30 m.sup.2 /g and a degree of whiteness of more than 90%. The film is used as a dielectric in a capacitor and shows improved electrical properties.
    Type: Grant
    Filed: February 17, 1989
    Date of Patent: March 20, 1990
    Assignee: Hoechst Aktiengesellschaft
    Inventors: Gunter Schloegl, Lothar Bothe, Guenther Crass, Thomas Wilhelm, Karl E. Helf