Process for enhancing sizing efficiency in filled papers

摘要

A papermaking process with improved sizing efficiency and reduced size reversion is characterized by the use of a calcium carbonate pigment which is surface treated with an anionic starch-soap complex. The starch-soap complex is precipitated onto the pigment surfaces to provide bonding sites for sizing agents which impart water repellency to the paper. The sizing agents become bound to the starch component of the starch-soap complex to yield more reacted size in paper webs formed from the furnish than would be present without the use of the treated pigment. The use of the surface treated pigment also allows the papermaker to increase the filler content of the paper without sacrificing dry strength properties.