Fiber Property Modification by Mechanical Pretreatment, 2001 Papermakers Conference Proceedings

The specific mechanical pretreatment, which consists of compressive impact and shear action on wood fibers, before refining increased WRV significantly while keeping fiber length from shortening. Laboratory beating on the mechanically pretreated and the control fiber furnish showed significantly higher WRVs for the pretreated one at equivalent freeness levels. Handsheet study also showed that the strength properties (breaking length, tear index, and burst index) of the pretreated fiber furnishes were increased a lot at equivalent freeness levels. The effect of mechanical pretreatment on different fiber furnishes were, however, quite different from one another. The fiber length, the fiber chemical compositions, and the pretreatment temperature could greatly affect the results of the pretreatment. This pretreatment process was applied to recycled fibers such as OCC, and we obtained large improvement of strength properties without use of synthetic polymers and without causing drainage disadvantage. Our next goal is to design a pilot scale pretreatment device, which can compromise the fiber length differences and the running temperature adjustment.