On the characterization of mechanical pulp fines - A review

Fines can be regarded as one of the most important fractions in mechanical pulps because of their significant effect on most paper properties. Fines have been studied extensively over the past decades, but the approach to fines characterization has been diffuse and unsystematic. The characterization of fines is more problematic than that of the whole pulp because of the small particle size. Isolation, treatment and measurement of fines are laborious and usually require special equipment. In the same way as pulp characterization, also fines characterization must have an objective. It is suggested that one objective in fines characterization could be to determine the papermaking potential of the fines. A profound understanding of the effects of fines on the sheet structure and of the factors determining fines properties should also be acquired. In this review, characteristics of mechanical pulp fines, their generation, research methods and effects on paper properties are reviewed. A characterization strategy for fines is proposed.