Laboratory kraft pulping of juvenile tropical pines: Pinus patula, P. tecunumanii, P. maximinoi, and P. chiapensis

Laboratory-scale kraft pulping was carried out using wood chips from 8-year-old trees of Pinus patula, P. tecunumanii, P. maximinoi, and P. chiapensis. Samples were pulped to target kappa nos. 50 ,38, and 28. A portion of the kappa-no.-28 pulps was bleached to 85% brightness (ISO) using an OCOH sequence. Pulps were refined using a Valley beater at four levels, and handsheets were evaluated for burst and tear. Pinus chiapensis required the highest active alkali to achieve a given kappa number, while P. patula required the least. With refining, tear index for the four pine species reached similar levels. For wood from juvenile tropical pines, the results are within accepted international standards for pulp.