THE EFFECT OF FILLERS ON PAPER FRICTION PROPERTIES

While factors like wood species, the pulping process, and washing influence paper friction properties, the influence that fillers have on the coefficient of friction (COF) is not widely understood. To establish the impact of fillers, several types were studied using the horizontal plane method of measuring friction. These filler types included hydrous kaolin, calcined kaolin, talc, and synthetic precipitated silica and silicate (PSS) pigments. Using data from measurements of both bandsheets and commercially made papers, a high degree of correlation was found between the sheet kinetic COF and filler properties. Key filler properties such as pigment surface area and porosity were determined to have a major effect on friction development. Sheet friction increases as pigment surface area and porosity increase. The results demonstrate the ability of porous synthetic PSS pigments to dramatically alter paper friction properties.