Chemithermomechanical Pulping of Second-Growth Lodgepole Pine from Western Canada, 1994 Pulping Conference Proceedings

J.V. Hatton, S.S. Johal

The properties of chemithermomechanical pulps from second-growth lodgepole pine trees have been determined. The butt portions of each of 12 trees were separated into juvenile wood and mature wood components for mechanical pulping, and for evaluation of pulp (fiber) and handsheet properties.

Juvenile wood required 20% more energy than did mature wood to refine to 130 mL Csf; Alberta samples required 14% more energy than did those from British Columbia to reach the same freeness level. Chemithermomechanical pulp fibers from mature wood were generally longer than those from juvenile wood, but CTMP pulps from Alberta samples had fibers that were more flexible and finer than their British Columbia counterparts. Thus, the tensile and tearing strengths of mature wood pulps were usually, but not always, superior to those of juvenile wood pulps. Scattering coefficients of juvenile wood pulps at a freeness of 130 mL Csf were consistently higher than those of their corresponding mature wood pulps because of their finer fibers.