Patents by Inventor Renate Hoppe

Renate Hoppe 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).

  • Patent number: 4419440
    Abstract: The present invention relates to a process for the introduction of water-insoluble photographic additives, especially dye couplers, in aqueous media with the application of high-boiling organic solvents. The purpose of the invention is to develop an improved process for the introduction of hydrophobic photographic additives, especially dye couplers, in gelatin or other hydrophilic bonding agents in order to produce stable dispersions suitable for storage. This invention has the object of creating a new, high-boiling solvent for the dispersion of hydrophobic photographic additives. According to the invention, this aim is achieved by employing phosphonic acid diamides, methane bisphosphonic acid diamides, phosphonic acid esters, methane bisphosphonic acid esters or mixed phosphonic acid esters or methane bisphosphonic acid ester amides as high-boiling solvents.
    Type: Grant
    Filed: November 9, 1981
    Date of Patent: December 6, 1983
    Assignee: VEB Filmfabrik Wolfen
    Inventors: Lothar Kuhnert, Burkhard Costisella, Christoph Roth, Walter Kroha, Wolfgang Baumbach, Renate Hoppe