PURPOSE: To obtain cellulose having very good properties by an organosolve method similar to a sulfate method by impregnating a cellulose plant fiber material with alcohol and thereafter delignificating it under the condition of less alcohol than the previous stage.
CONSTITUTION: For delignification of a plant fiber material, particularly scraps, with alcohol, the plant fiber material is at first impregnated with alcohol. Then, the impregnated material is delignificated by using less alcohol than the above impregnating stage. Specifically, the plant fiber material is impregnated with alcohol or a mixture of pure alcohol and water at a high temp. until a phase equilibrium state is obtained between the impregnating soln. and liquid in the plant fiber material, and thereafter delignification treatment may be carried out by using an alkali/alcohol/water mixture at a high temp. An amount of alcohol in the impregnation stage is preferably 40-50 wt.%. Further, an amount of alcohol in the delignification stage is preferably 20-30 wt.% of the delignification soln.
GERUHARUTO DAARUMAN
HAINRIHI REOPORUTO