Patents by Inventor Daniel Hoffner

Daniel Hoffner 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 of pigment grade iron oxides from ferrous sulphate and the resulting Fe.sub.2 O.sub.3 pigments
    Patent number: 4261966
    Abstract: Pigment grade Fe.sub.2 O.sub.3 is prepared from ferrous sulphate by a roasting process. The ferrous sulphate, partly dehydrated and granulated, is partially converted to the oxide by roasting. After elimination of soluble constituents by washing with water, the oxide is subjected to pigmentary calcination and then crushed and optionally micronized. This process makes it possible to prepare red pigments of excellent quality characterized particularly by pure tints ranging from orange-red to purplish-red. The oil absorptions are especially low. Low toxic impurity concentrations permit the use of these pigments in foodstuffs.
    Type: Grant
    Filed: October 2, 1979
    Date of Patent: April 14, 1981
    Assignee: Thann et Mulhouse, Corp.
    Inventors: Pierre Portes, Jean M. Trautmann, Daniel Hoffner