Patents by Inventor Sigmar Hartmann

Sigmar Hartmann 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).

  • Core yarn with a core of high strength polyester material, production thereof and use of selected polyester material for producing core yarns
    Patent number: 5735110
    Abstract: In core yarns, a) the polyester material of the core filaments has an average molecular weight corresponding to a relative solution viscosity of at least 1.9, and b) the core has a specific strength of at least 60 cN/tex, the core yarns producing a seam length to rupture of more than 800 cm in a sewing test under aggravated conditions.The core yarns are obtainable by a process comprising the measures of: i) producing multifilament yarns based on polyesters having an average molecular weight corresponding to a relative solution viscosity of at least 1.9 by melt spinning polyester with a takeoff speed of at least 1500 m/min.
    Type: Grant
    Filed: March 18, 1997
    Date of Patent: April 7, 1998
    Assignee: Hoechst Aktiengesellschaft
    Inventors: Erhard Kruger, Aribert Reinsch, Sigmar Hartmann