Resin in bisulfite pulp from Pinus radiata wood and its relationship to pitch troubles

Abstract

The resin content of bisulfite pulp from Pinus radiata D. Don was determined at various stages in its manufacture and the changes in the composition of the resin studied. About 50% of the resin present in the wood was removed during cooking, an additional 11% by blowpit washing, and a further 8% by screening. Resin acids and fatty acids were preferentially lost during washing and screening of the pulp, whereas the amount of fatty acid esters in the pulp was not significantly reduced. There was no selective loss of individual resin acids and fatty acids during washing and screening of the pulp. Pitch deposits from the pulp mill and paper machine were mixtures of resin and acetone-insoluble material, and the trouble caused by a deposit was related to its viscosity. The resin in these deposits contained about 50% acidic compounds. The fatty acid and unsaponifiable fractions showed the greatest tendency to accumulate in pitch deposits.

Citation

Nelson, P.J.; Hemingway, Richard W. 1971. Resin in bisulfite pulp from Pinus radiata wood and its relationship to pitch troubles. TAPPI 54(6):968-971