Patents by Inventor Wolfgang Kreth

Wolfgang Kreth 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: 4885034
    Abstract: In a process for producing a composite TiO.sub.2 pigment which contains a white inert extender, the neutralization is simplified and the need for washing processes is eliminated in that a metatitanic acid suspension, which contains free and combined sulfuric acid and has been purified for the removal of chromophoric elements, is neutralized by an addition of calcium oxide and/or barium oxide in quantities which are stoichiometric with respect to total sulfate, the calcium sulfate and/or barium sulfate is precipitated in an intimate mixture with the metatitanic acid, and the coprecipitate is separated and dried. The precipitated calcium sulfate and/or barium sulfate is contained in the coprecipitate in an amount from 1 to 25% by weight.
    Type: Grant
    Filed: August 24, 1987
    Date of Patent: December 5, 1989
    Assignee: Metallgesellschaft Aktiengesellschaft
    Inventors: Wolfgang Kreth, Wolf-Dieter Griebler