Prediction of strength parameters for softwood kraft pulps

This work presents results from a study which was undertaken to explore the relationship between the choice of wood raw material and the properties of the resulting kraft pulps expressed in terms of physical parameters for the pulps and strength properties of hand sheets made from the pulps. Softwood haft pulps were made from 20 different types of wood samples, which were selected according to an experimental design. A number of physical parameters characterizing fiber properties were determined for the bleached pulps. Multivariate data analysis was used to model the influence of the fiber properties on strength parameters. The results showed that both beating and fiber properties are important for the strength parameters. It was concluded that the strength parameters were determined by the fiber properties for a given level of beating treatment. At a given beating, tear index was, for example, best predicted from the fiber coarseness. At a given tensile index, tear index correlated highly with the fiber length and was well predicted from the fiber length distribution alone.