Patents Assigned to M. Peterson & Son A/S
  • Process for delignification of chemical wood pulp using sodium sulphite or bisulphite prior to oxygen-alkali treatment
    Patent number: 4560437
    Abstract: In the delignification of chemical wood pulp with oxygen and alkali a larger reduction of the kappa number may be obtained without an increase in the charge of oxygen or alkali, provided the pulp is pretreated with a solution of sulphite or bisulphite in order to introduce hydrophilic groups in the sulphate lignin in the chemical wood pulp.
    Type: Grant
    Filed: June 22, 1984
    Date of Patent: December 24, 1985
    Assignee: M. Peterson & Son A/S
    Inventors: Peder J. Kleppe, Sverre Storebraten