| abstract |
The present invention relates to a method of producing paper or board and to an in-sizing system for providing improved retention of hydrophobic in-sizing agent. The in-pulp sizing system comprises as a first component a hydrophobic in-pulp sizing agent selected from the group consisting of alkenyl succinic anhydride (ASA), alkyl ketene dimer (AKD), Rosin gum and any combination thereof, and a water-soluble polymer product containing, as a second component, an amphoteric polyacrylamide having a neutral or cationic net charge at pH 7 and a weight average molecular weight of 700,000-18,000,000 g /mol and the total ionization degree is 4-28 mol-%, wherein the first and second components are provided as separate components or as a combination of first and second components. |