Method for increasing the advantages of starch in pulped cellulosic material in the production of paper and paperboard

摘要

The invention relates to a method for increasing the benefit from starch in pulped, preferably repulped cellulosic material at paper or paperboard manufacturing comprising the steps of (a) pulping a cellulosic material containing a starch; (b) treating the cellulosic material containing the starch with one or more biocides, preferably in the thick stock area; and (h) adding an ionic polymer and preferably, an auxiliary ionic polymer to the cellulosic material; wherein the ionic polymer and the optionally added auxiliary ionic polymer preferably have a different average molecular weight and preferably a different ionicity, wherein the tonicity Is the molar content of ionic monomer units relative to the total amount of monomer units.