Pitch problems in pulping and bleaching of Sarawak hardwoods. IV : An efficient method of resin speck removal from Dipterocarpaceae pulps

Addition of talc at the cooking stage was effective in reducing resin specks. Bleaching reduced the incidence of resin specks; pulps were bleached by single stage (D), four stage OD(EO)OD, and five stage (CEDED) processes. Speck reduction was greatest in the four stage sequence. One wood, Shorea kunstleri, containing the hydrophobic polymers β and γ resene in the resin canals, gave only a small response to the treatments. This wood is not recommended for pulping. For the other five woods total resin speck removal ratios were c. 85 to 90%