Patents by Inventor Gerhard Zirkenbach

Gerhard Zirkenbach 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).

  • Aqueous liquid formulations of pyrazoline brighteners
    Patent number: 7300474
    Abstract: The claimed liquid formulations contain an organic acid and a branched mono- or di-alcohol. The addition of the alcohol improves the storage stability of the liquid formulations.
    Type: Grant
    Filed: February 20, 2003
    Date of Patent: November 27, 2007
    Assignee: Clariant Produkte (Deutschland) GmbH
    Inventors: Gerhard Zirkenbach, Alexander Lerch
  • Aqueous liquid formulations of pyrazoline brighteners
    Publication number: 20050251931
    Abstract: The claimed liquid formulations contain an organic acid and a branched mono- or di-alcohol. The addition of the alcohol improves the storage stability of the liquid formulations.
    Type: Application
    Filed: February 20, 2003
    Publication date: November 17, 2005
    Inventors: Gerhard Zirkenbach, Alexander Lerch
  • Method for the production of optically brightened polyester
    Publication number: 20050101703
    Abstract: In the production of polyester from a polyol, preferably di-alcohol, and a polycarboxylic acid, preferably dicarboxylic acid, an optical brightener is added in the esterification process whose structure is free from open-chain ethylenic double bonds and as a result is chemically stable to the free acid used.
    Type: Application
    Filed: March 16, 2002
    Publication date: May 12, 2005
    Inventors: Thomas Martini, Alexander Lerch, Gerhard Zirkenbach
  • Process for the preparation of pyrene compounds
    Patent number: 5322941
    Abstract: The invention relates to a process for the preparation of pyrene compounds of the formula ##STR1## by reaction of cyanuric chloride with pyrene in the presence of an aluminum halide in an aromatic solvent in a Friedel-Crafts reaction, which comprises using as solvent non-polar, halogen-free aromatic compounds, preferably composed of methyl-, ethyl- and/or propyl-substituted benzene, and carrying out the reaction in the presence of non-aqueous bases, particularly carbonates of alkaline earth and alkali metals, bicarbonates of alkaline earth and alkali metals, and also alkali metal alcoholates of the formula MOR (R=C.sub.1 -C.sub.4 -alkyl, M=alkali metal).
    Type: Grant
    Filed: January 8, 1992
    Date of Patent: June 21, 1994
    Assignee: Hoechst Aktiengesellschaft
    Inventors: Bernhard Mees, Gerhard Zirkenbach