Process for production of alkali cellulose in the absence of an aqueous liquid phase

Claim 1

PROCESS FOR PRODUCING CYSTALLINE CELLULOSIC PULP OF LOW VISOCITY AND HIGH A-CELLULOSE CONTENT HAVING A RELATIVELY HIGH PURITY WHICH COMPRISES: (A) IMPREGNATING SUBDIVIDED FIBROUS CELLULOSIC MATERIAL WITH AQUEOUS ALKALINE LIQUOR UNTIL A CHARGE OF EFFECTIVE ALKALI OF AT LEAST 10% BY WEIGHT IS OBTAINED, CALCULATED AS NA2O AND BASED ON DRY FIBROUS MATERIAL, SAID ALKALINE LIQUOR HAVING EFFECTIVE CONCENTRATION, CALCULATED AS NA2O, OF AT LEAST 3.1% BY WEIGHT, CORRESPONDING TO AT LEAST 4% NAOH BY WEIGHT. (B) REMOVING WATER BY EVAPORATION FROM SAID IMPREGNATED SUBDIVIDED FIBROUS MATEIAL IN AN ATMOSPHERE INERT TO ALKALI UNTIL SUBSTANTIALLY ALL AQUEOUS LIQUID PHASE HAS DISAPPEARED AND A WATER VAPOUR PRESSURE ESSENTIALLY LOWER THAN THAT OF SATURATION IS OBTAINED, (C) HEATING THE PRODUCT THUS OBTAINED IN SAID INERT ATMOSPHERE AT A TEMPERATURE OF 80*C.-220*C. AT THE AFORESAID WATER VAPOUR PRESSURE IN THE ABSENCE OF ANY SUBSTANTIAL AQUEOUS LIQUID PHASE TO OBTAIN CRYSTALLINE CELLULOSIC PULP OF LOW VISCOSITY, HIGH A-CELLULOSE CONTENT AND RELATIVELY HIGH PURITY AND (D) RECOVERING SAID CRYSTALLINE CELLULOSIC PULP.