Patents by Inventor Dennis I. MacDonald

Dennis I. MacDonald 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: 6372089
    Abstract: Disclosed are stable, aqueous colloidal silicas having surface area of greater than 700 m2/g and S-values of from 20-50. These colloidal silicas do not require treatment with surface treatment agents such as aluminum to achieve stability. These colloidal silica aquasols can be produced and stored at concentrations of greater than 7 percent by weight SiO2 solids, and even as high as 15 percent by weight solids or higher, and remain stable at room temperature for at least 30 days compared to art-known silica aquasols. These colloidal silica sols demonstrate advantageously improved performance over art-known colloidal silica sols in applications such as in drainage and retention in papermaking processes. Also disclosed are processes for making aqueous colloidal silicas of the invention and the use of such colloidal silicas in papermaking processes.
    Type: Grant
    Filed: February 14, 2000
    Date of Patent: April 16, 2002
    Assignee: Nalco Chemical Company
    Inventors: Bruce A. Keiser, Maureen B. Nunn, Cheng-Sung Huang, Dennis I. MacDonald