Using X-Ray Photoelectron Spectroscopy to Measure Fiber Coverage of Coated Paper, 2003 Spring Technical Conference Proceedings

Methods of assessing the ability of pigments to cover fibers in low and ultra-low weight coatings are generally qualitative in nature. In low coat weight applications, we have found it difficult to discern changes in coverage using visual methods. Since changes in pigment properties can effect final product quality, a quantitative method for determining the effect of coating variations on sheet properties was sought. X-ray photoelectron spectroscopy (XPS), a technique capable of analyzing coating compositions, was employed for this purpose. Two approaches were taken. Coatings on groundwood substrate were evaluated and showed that although the method had promise, interference from coating formulation binders degraded analysis. Applying an easily detectable element not present in either the paper or coating to the basesheet improved the statistics of the measurement significantly. Results from tagged and untagged systems are presented.