Patents by Inventor Johnny Yrjans

Johnny Yrjans 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).

  • Papermaking process
    Patent number: 4980025
    Abstract: In a process for making paper from an aqueous paper pulp, especially a pulp containing bleached/unbleached mechanical pulps or unbleached chemical pulps, a combination of chemicals is added for improving drainage and retention. As drainage-and retention-improving aids are added a cationic polyacrylamide and a sol of colloidal inorganic particles having at least one surface layer of aluminium silicate or aluminum-modified silicic acid.
    Type: Grant
    Filed: July 17, 1989
    Date of Patent: December 25, 1990
    Assignee: Eka Nobel AB
    Inventors: Kjell R. Andersson, Pavol Barla, Johnny Yrjans