Rapid acetylation of cellulose crystallite aggregates

Claim 1

THE METHOD OF ACETYLATING CELLULOSE CRYSTALITE AGGREGATES UNDER SUBSTANTIALLY ANHYDROUS CONDITIONS TO PRODUCE THE TRIACETATE DERIVATIVE THEREOF WHICH COMPRISES FORMING A REACTION MIXTURE BY MIXING, PER PART BY WEIGHT OF SAID AGGREGATES IN DRY FORM, 1.89 TRO 3 PARTS OF ACETIC ANHYDRIDE TO FORM A STIRRABLE SLURRY, SAID AGGREGATES HAVING A LEVEL-OFF D.P., THEN ADDING 0.004 TO 0.007 PART OF SULFURIC ACID AS A CATALYST, THE LIQUID-TO-SOLID RATIO OF THE REACTION MIXTURE BEING 1.89/1 TO 3/1, REACTING SAID AGGREGATES AND ANHYDRIDE IN THE ABSENCE OF THE ADDITION OF ACETIC ACID PER SE AND IN THE ABSENCE OF EXTERNALLY APPLIED HEATING AND COOLING, PERMITTING THE TEMPERAUTRE OF THE REACTION MIXTURE TO RISE TO A PEAK VALUE THEREOF IN THE RANGE OF 60 TO 80*C. OVER A PERIOD OF 10 TO 15 MINUTES, AND RECOVERING A SUBSTANTIALLY WATER-FREE SPINNABLE SOLUTION OF THE TRIACETATE OF SAID CELLULOSE CRYSTALLITE AGGREGATES IN THE FORM OF SAID REACTION MIXTURE; SAID SOLUTION HAVING A TRIACETATE CONTENT OF UP TO 61.5% BY WEIGHT THEREOF, SAID TRIACETATE HAVING A D.P. OF 90 TO 240 ANHYDROGLUCOSE UNITS, AN ACETYL CONTENT OF 41 TO 44.8%, AND A SULFUR CONTENT LESS THAN ABOUT 0.05% BY WEIGHT, AND SAID SOLUTION BEING FREE OF UNREACTED PARTICLES OF AGGFREGATES WHEN EXAMINED UNDER THE MICROSCOPE.

Claim 2

THE METHOD OF ACETYLATING CELLULOSE CRYSTALITE AGGREGATES UNDER SUBSTANTIALLY ANHYDROUS CONDITIONS TO PRODUCE THE TRIACETATE DERIVATIVE THEREOF WHICH COMPRISES FORMING A REACTION MIXTURE BY MIXING, PER PART BY WEIGHT OF SAID AGGREGATES IN DRY FORM, 1.89 TRO 3 PARTS OF ACETIC ANHYDRIDE TO FORM A STIRRABLE SLURRY, SAID AGGREGATES HAVING A LEVEL-OFF D.P., THEN ADDING 0.004 TO 0.007 PART OF SULFURIC ACID AS A CATALYST, THE LIQUID-TO-SOLID RATIO OF THE REACTION MIXTURE BEING 1.89/1 TO 3/1, REACTING SAID AGGREGATES AND ANHYDRIDE IN THE ABSENCE OF THE ADDITION OF ACETIC ACID PER SE AND IN THE ABSENCE OF EXTERNALLY APPLIED HEATING AND COOLING, PERMITTING THE TEMPERAUTRE OF THE REACTION MIXTURE TO RISE TO A PEAK VALUE THEREOF IN THE RANGE OF 60 TO 80*C. OVER A PERIOD OF 10 TO 15 MINUTES, AND RECOVERING A SUBSTANTIALLY WATER-FREE SPINNABLE SOLUTION OF THE TRIACETATE OF SAID CELLULOSE CRYSTALLITE AGGREGATES IN THE FORM OF SAID REACTION MIXTURE; SAID SOLUTION HAVING A TRIACETATE CONTENT OF UP TO 61.5% BY WEIGHT THEREOF, SAID TRIACETATE HAVING A D.P. OF 90 TO 240 ANHYDROGLUCOSE UNITS, AN ACETYL CONTENT OF 41 TO 44.8%, AND A SULFUR CONTENT LESS THAN ABOUT 0.05% BY WEIGHT, AND SAID SOLUTION BEING FREE OF UNREACTED PARTICLES OF AGGFREGATES WHEN EXAMINED UNDER THE MICROSCOPE.