Patents by Inventor Birgitta Sunden

Birgitta Sunden 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).

  • Semisynthetic paper structure on a urea basis
    Patent number: 4183783
    Abstract: A semisynthetic paper with low bulk comprises a continuous, chemically bonded, open fibre network formed by cellulosic vegetable fibres and fragments of urea-formaldehyde condensate, the fragments being precured before paper web formation and being cured a second time when drying the paper web.A method of producing a semisynthetic paper with low bulk comprises the steps of forming precured fragments of a urea-formaldehyde condensate, forming a stock of the fragments and cellulosic vegetable fibres, including in the stock a water-insoluble latent curing agent, forming a paper web from the stock, and drying the paper web, the fragments being cured a second time during the drying operation.
    Type: Grant
    Filed: September 21, 1977
    Date of Patent: January 15, 1980
    Assignee: Olof Sunden
    Inventors: Olof Sunden, Birgitta Sunden