Patents by Inventor Axel Westerhaus

Axel Westerhaus 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).

  • Heat stable iron oxide pigments of upsilon-Fe.sub.2 O.sub.3 structure, a process for their production and their use
    Patent number: 5049193
    Abstract: A pigment useful for coloring building materials such as bricks is a heat-stable isometric iron oxide brown pigment of .gamma.-Fe.sub.2 O.sub.3 structure which has a silicon content, expresed as SiO.sub.2, of 0.1 to 12% and an Al content, expressed as Al.sub.2 O.sub.3, of 0.02 to 5%.
    Type: Grant
    Filed: October 29, 1990
    Date of Patent: September 17, 1991
    Assignee: Bayer Aktiengesellschaft
    Inventors: Bernd Krockert, Gunter Buxbaum, Axel Westerhaus, Horst Brunn
  • Iron oxide pigments, a process for their preparation and their use
    Patent number: 4990189
    Abstract: Pigments for printing inks and magnetic toners are iron oxide pigments with a rhombic dodecahedral form and an average particle diameter of from 0.05 to 3.0 .mu.m with a standard deviation of the particle size distribution of .+-.30%.
    Type: Grant
    Filed: June 8, 1989
    Date of Patent: February 5, 1991
    Assignee: Bayer Aktiengesellschaft
    Inventors: Jurgen Wiese, Axel Westerhaus, Jurgen Scharschmidt, Gunter Buxbaum
  • Color intensive iron oxide black pigments obtained by the nitrobenzene reduction process and a process for its preparation
    Patent number: 4966641
    Abstract: Iron oxide black pigment with improved color intensity is produced by subjecting finely divided pigment obtained from reaction of metallic iron with aromatic nitro compounds to a heat treatment of 200.degree. to 800.degree. C. under a non-oxidizing atmosphere for a time of 2 minutes to 5 hours.
    Type: Grant
    Filed: December 7, 1988
    Date of Patent: October 30, 1990
    Assignee: Bayer Aktiengesellschaft
    Inventors: Axel Westerhaus, Karl-Werner Ganter, Gunter Buxbaum