Mechanical Pulping of Cedar (Cryptomeria japonica)

Abstract

Cedar (Cryptomeria japonica) is the most abundant softwood species in Japan and has been used for construction materials, furniture, barrels, shoes and so forth. However it was regarded unsuitable for mechanical pulping as it contains relatively large amount of lignin and extractives compared with other softwood species such as spruce, hemlock and radiata pine. We tried several thermomechanical processes by the laboratory refiner. changing chemical pretreament and refining temperature. It was found that Cedar CTMP (chemithermomechanical pulp) had the high light scattering coefficient and brightness. and was suitable to produce printing grade papers.