Patents by Inventor Donald E. Loeffler

Donald E. Loeffler 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).

  • Gear oil viscosity index improvers
    Patent number: 5070131
    Abstract: A gear oil composition is provided, the composition comprising a hydrogenated star conjugated diolefin polymer having arms with weight average molecular weights between about 3,000 and about 15,000. Such star polymers are effective as viscosity index improvers, and yet are sufficiently shear stable for service in gear oil lubricants.
    Type: Grant
    Filed: September 28, 1990
    Date of Patent: December 3, 1991
    Assignee: Shell Oil Company
    Inventors: Robert B. Rhodes, Rudolf J. Eckert, Donald E. Loeffler