Patents by Inventor Harry J. Marshall

Harry J. Marshall 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).

  • Glass microbubbles
    Patent number: 4767726
    Abstract: Glass microbubbles having, on a weight basis, a composition consisting essentially of 70-80% SiO.sub.2, 8-15% CaO, 3-8% Na.sub.2 O, and 2-6% B.sub.2 O.sub.3, and about 0.2-1.5% SO.sub.3 and having a CaO:Na.sub.2 O ratio of 1-3.5. These microbubbles, which are made of significantly less expensive raw materials than conventional products, can also be made with a higher percent "floaters" and a lower average density. Certain substitutions can be made for at least a portion of each of the first three oxides.
    Type: Grant
    Filed: January 12, 1987
    Date of Patent: August 30, 1988
    Assignee: Minnesota Mining and Manufacturing Company
    Inventor: Harry J. Marshall