Effects of Production Variables of Fines-PCC Composite Fillers on Paper Properties (I): Stirring Speed and Dosage of Flocculants

Abstract

A composite filler was developed by pre-flocculation of hardwood bleached kraft pulp (HwBKP) fines and precipitated calcium carbonate (PCC) with flocculants like cationic polyacrylamide (C-PAM) and bentonite. The effects of stirring rate and flocculant dosage during the production of the composite filler on the mechanical and the optical properties of handsheets were investigated. The handsheets using the fines-PCC composite filler showed higher strength properties than that with the conventional loading at a given ash content of paper, showing the possibility of the production of high loaded paper with the fines-PCC filler. Increasing average floc size of the composite filler by decreasing stirring rate resulted in increased strength properties, while the optical properties were not influenced by the stirring rate. Dosage of flocculant influenced the formation and the strength properties of handsheets while the optical properties was only affected by the ash content of handsheets.