Patents by Inventor John F. Donlon

John F. Donlon 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).

  • Opaque polyester film containing fine carbon black particles
    Patent number: 4603073
    Abstract: A magnetic recording medium has a biaxially-oriented polyester film base which includes carbon black beads having a median diameter from 50 to 500 nm and is substantially free from beads or agglomerates more than 5 micrometers in diameter. The beads provide opacity such as is often required of the flexible recording disk of a diskette. The film base may be either a single layer, throughout which the beads are uniformly dispersed, or it may be multi-layer, e.g., a central layer containing the carbon black beads and two surface layers which are free from the beads.
    Type: Grant
    Filed: June 24, 1985
    Date of Patent: July 29, 1986
    Assignee: Minnesota Mining and Manufacturing Company
    Inventors: Brenda L. Renalls, Douglas G. Pedrotty, John F. Donlon