RECYCLING BEHAVIOR OF THERMOMECHANICAL PULP - EFFECTS OF REFINING ENERGY

Recycling characteristics of thermomechanical pulps produced from jack pine and black spruce have been studied using standard laboratory pro cedures. The results indicate that the specific energy input has a pro found effect on the papermaking properties of pulps during recycling. Short-fiber fractions behave differently when compared with long-fiber fractions. The sheet density and tensile strength of high-energy pulp s tend to increase somewhat, while those of low energy tend to decreas e. In most cases, the tear index augments slightly or remains unchange d during recycling. In almost all the pulps studied, specific light sc attering suffered significant loss. The new recycling effect on pulp c haracteristics seems to depend on the distribution of fiber fractions in the pulps under study. However, much research is needed.