Patents by Inventor Lars Harald Petander

Lars Harald Petander 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).

  • Patent number: 5695609
    Abstract: The invention relates to a process for the production of paper by adding to an aqueous fiber suspension, which possibly contains a filler, auxiliary agents for improving retention and/or dewatering, the auxiliary agents being a cationic long-chain polyacrylamide and an aluminum salt, and by dewatering the obtained fiber suspension during the sheet-forming stage. According to the invention, the said aqueous fiber suspension, possibly containing a filler, to which the cationic long-chain polyacrylamide has first been added, is subjected to shearing forces, whereafter there is added to it, directly before sheet forming, a polymeric aluminum salt or an aluminum salt, in which case a base or an acid is added, when necessary, to the said fiber suspension so that the pH be within the range 7-9 before the sheet forming, in which case aluminum hydroxy particles having anionic surface charges will be formed in situ.
    Type: Grant
    Filed: January 19, 1996
    Date of Patent: December 9, 1997
    Assignee: Kemira Oy
    Inventors: Lars Harald Petander, Tore Anders Duvnas