Patents by Inventor Hubertus P. A. Gielkens

Hubertus P. A. Gielkens 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).

  • Novel process for the preparation of lead molybdate pigments and novel lead molybdate pigments
    Patent number: 5007963
    Abstract: A process for the preparation of lead molybdate pigments containing lead chromate, lead sulfate and lead molybdate, which comprises preparing the lead molybdate pigments by reacting an aqueous solution of a lead salt with an aqueous solution containing chromate, molybdate and sulfate salts or with an aqueous solution of each of said salts using 2 to 5 mol % of lead molybdate seed crystals, based on the total molar amount of lead chromate, lead sulfate and lead molybdate. The lead molybdate pigments so obtained are strong and are highly suitable for coloring organic materials of high molecular weight.
    Type: Grant
    Filed: October 17, 1988
    Date of Patent: April 16, 1991
    Assignee: Ciba-Geigy Corporation
    Inventors: Leonardus J. H. Erkens, Gerben P. Algra, Herman J. J. M. Geurts, Hubertus P. A. Gielkens