Patents by Inventor Herbert Letter

Herbert Letter 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).

  • Dye dispersants: aryl sulphonic acid-formaldehyde condensate or ligninsulfonate
    Patent number: 5186846
    Abstract: Dispersants of increased bioeliminability or biodegradability for use in dye and pigment preparations, as tanning aids, in plastics production and in crop protection formulations contain from 3 to 50% by weight of one or more aromatic or long-chain aliphatic carboxylic acids, salts thereof or anhydrides thereof or a mixture thereof.
    Type: Grant
    Filed: June 13, 1991
    Date of Patent: February 16, 1993
    Assignee: BASF Aktiengesellschaft
    Inventors: Ralf Brueckmann, Willi Bury, Johannes P. Dix, Manfred Herrmann, Waldemar Dlugosch, Erich Kromm, Herbert Letter, Norbert Zimmermann, Wolf-Dieter Kermer, Klaus Taeger