Kraft Cooking and Bleaching Ability of Lowdensity Acacia Wood and Hardwoods with Varying Chemical Characteristics of Lignin

抄録

Low-density acacia（Acacia hybrid）wood chips, relatively high-density acacia（Acacia mearnsii）wood chips, eucalyptus（Eucalyptus globulus）wood chips, and Japanese mixed hardwood chips were cooked through a kraft cooking process using the continuous conventional mill digester. Chemical composition of these wood chips and properties of the obtained pulps were compared. Low-density acacia wood chips showed the highest lignin content, the lowest combined yield of syringaldehyde and vanillin obtained by alkaline nitrobenzene oxidation analysis of the lignin, and the worst cooking response among the four kinds of woods. When the mixture ratio of low-density acacia wood chips in the feedstock was increased, pulp yield and hemicellulose （xylan）content of the pulp were decreased. The physical properties（breaking length, bursting strength, and folding endurance）of the bleached kraft pulp hand sheets slightly decreased with decreasing xylan content of the pulp. However, changes in the hand sheet strength properties had negligible effects on the quality of the paper products.