Patents by Inventor Birgit Kessler

Birgit Kessler 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).

  • Process for the preparation and work-up of N-hydroxyalkylchitosans soluble in aqueous medium
    Patent number: 6090928
    Abstract: The present invention relates to a process for the preparation and work-up of N-hydroxyalkylchitosans soluble in aqueous media, comprising the measuresdispersion of chitosan in an aqueous medium,subsequent hydroxyalkylation of the dispersed chitosan andsubsequent work-up of the N-hydroxyalkylchitosan, which comprises carrying out the hydroxyalkylation up to an average degree of substitution (DS) of 2.0, preferably 1.5 to 2.0, if desired removing some of the aqueous medium after the hydroxyalkylation and before the work-up and performing the work-up of the N-hydroxyalkylchitosan by drying.
    Type: Grant
    Filed: March 24, 1994
    Date of Patent: July 18, 2000
    Assignee: Clariant GmbH
    Inventors: Reinhard Donges, Diethart Reichel, Birgit Kessler
  • Process for producing fiber-reinforced xerogels and their use
    Patent number: 5866027
    Abstract: The invention relates to a process for producing modified, fiber-reinforced xerogels having porosities greater than 60% and xerogel matrix densities below 0.6 g/cm.sup.3 and to their use as thermal insulating material.
    Type: Grant
    Filed: February 21, 1997
    Date of Patent: February 2, 1999
    Assignee: Hoechst Aktiengesellschaft
    Inventors: Dierk Frank, Birgit Kessler, Andreas Zimmermann
  • Method for the subcritical drying of aerogels
    Patent number: 5811031
    Abstract: Process for the preparation of aerogels by subcritical drying of inorganic and organic hydrogels and lyogels to give aerogels, dielectric drying methods being used.
    Type: Grant
    Filed: July 7, 1997
    Date of Patent: September 22, 1998
    Assignee: Hoechst Aktiengesellschaft
    Inventors: Rolf-Michael Jansen, Birgit Kessler, Johann Wonner, Andreas Zimmermann
  • Method for the subcritical drying of aerogels
    Patent number: 5705535
    Abstract: Process for the preparation of aerogels by subcritical drying of inorganic and organic hydrogels and lyogels to give aerogels, dielectric drying methods being used.
    Type: Grant
    Filed: October 27, 1995
    Date of Patent: January 6, 1998
    Assignee: Hoechst Aktiengesellschaft
    Inventors: Rolf-Michael Jansen, Birgit Kessler, Johann Wonner, Andreas Zimmermann