Patents by Inventor Zenon C. Prusas

Zenon C. Prusas 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).

  • High-yield chemical pulping
    Patent number: 4869783
    Abstract: A chemical pulping process is disclosed wherein wood chips are partially defiberized such that the fibers in the chips are substantially separated from one another but sufficient interfiber bonding is maintained to preserve chip integrity and thereby provide chips having an open porous fibrous network; and the chips are subjected to chemical pulping at an elevated temperature to remove a majority of the lignin in the chips.
    Type: Grant
    Filed: July 1, 1988
    Date of Patent: September 26, 1989
    Assignee: The Mead Corporation
    Inventors: Zenon C. Prusas, Clarence L. Oates
  • Chemithermomechanical pulping process employing separate alkali and sulfite treatments
    Patent number: 4486267
    Abstract: A high yield chemithermomechanical (CTMP) process for obtaining high strength hardwood pulps is disclosed wherein hardwood chips are subjected to a two-stage chemical treatment prior to defibration, the first consisting of chip impregnation and reaction with an alkaline liquor followed by a second stage treatment with sulfite and/or bisulfite; in one embodiment peroxide is added to the alkaline liquor to enhance brightness.
    Type: Grant
    Filed: November 14, 1983
    Date of Patent: December 4, 1984
    Assignee: Mead Corporation
    Inventor: Zenon C. Prusas