Abstract:
Comparisons were made between anthraquinone modified soda pulp (soda-AQ), and methanol modified kraft (kraft-Me0H) and sulfite (sulfite-Me0H) pulps on western Oregon Douglas-fir. The kappa number, yield, brightness, and deshive values were all measured. The soda-AQ and kraft-Me0H pulps were the traditional brown color but the sulfite-Me0H pulps came out of the digester a bright yellow which darkened on exposure to ultraviolet light. The sulfite-Me0H pulps deshived at the highest yield of the three at 65% yield. The percent heartwood was varied in each case and had very little effect on the soda-AQ and kraft-Me0H pulps. It did cause a 45 point increase in kappa number in the sulfite-Me0H pulps. In both the kraft- Me0H and sulfite-Me0H pulps the chips pulped the fastest with 30% methanol in the liquor. Strength tests on the kraft-Me0H pulps showed strengths equivalent to those of traditional kraft cooks but the sulfite-Me0H strength values were considerably lower than those of the traditional kraft cooks.
