Slurry casting manufacture of nitrocellulose propellant grains

Claim 1

IN THE MANUFACTURE OF CAST PROPELLANT GRANS BY THE SLURRY CASTING PROCESS, THE IMPROVEMENT WHICH COMPRISES IN COMBINATION: FORMING A POURABLE CASTING SLURRY OF DENSIFIED COMMINUTED IRREGULAR NITROCELLULOSE PARTICLES WITH A CASTING LIQUID OF NITROCELLULOSE PLASTICIZER HAVING SOLVENT AND SWELLING ACTION ON NIROCELLULOSE SUFFICIENT TO FORM A SOLID, CONSOLIDATED PROPELLANT GRAIN UPON CURING; POURING THE RESULTING SLURRY INTO A MOLD; CURING THE SLURRY MIXTURE OF NITROCELLULOSE PARTICLES AND CASTING LIQUID IN THE MOLD UNTIL ALL OF SAID CASTING LIQUID IS ABOSRBED BY SAID NITROCELLULOSE PARTICLES THERE BY SWELLING AND COLLOIDIZING SAID NITROCELLULOSE PARTICLES TO FORM A SOLID CONSOLIDATED PROPELLANT GRAIN, SAID NITROCELLOSE PARTICLES HAVING BEEN PRODUCED BY CONTACTING A SLURRY OF FIBROUS NITROCELLULOSE WITH AGITATION IN A HEATED AQUEOUS BATH WITH AN ORGANIC LIQUID SOLVENT WHICH HAS ACTIVE SOLVENT POWER FOR SAID NITROCELLULOSE AND WHICH FROMS A MINIMUM BOILING AZETROPIC MIXTURE WITH WATER, SAID SOLVENT BEING PRESENT IN AN AMOUNT TO SOFTEN AND DESTROY THE FIBROUS STRUCTURE OF THE NITROCELLULOSE WITHOUT DISSOLUTION THEREOF, SAID BATH BEING HEATED TO AT LEAS THE BOILING POINT OF THE WATER-SOLVENT AZEOTROPE DURING THE ENTIRE PERIOD OF CONTACT BETWEEN SAID NITROCELLULOSE AND SAID SOLVENT, THEREAFTER REMOVING SUBSTANTIALLY ALL OF THE SOLVENT BY DISTILLATION WHILE CONTINUING AGITATION TO FORM SMOOTH, HARDENED, DENSIFIED AND RELATIVELY COARSE IRREGULAR PARTICLES OF NITROCELLULOSE HAVING A BULK DENSITY OF AT LEAST ABOUT 40 POUNDS PER CUBIC FOOT, DRY BASIS, COMMINUTING THE RESULTING DENSIFIED NITROCELLULOSE PARTICLES WITHOUT SUBSTANTIAL REDUCTION OF BULK DENSITY BY WET GRINDING TO PRODUCE DENSIFIED COMMINUTED IRREGULAR NITROCELLULOSE PARTICLES HAVING A WIDE DIVESITY OF PARTICLES SIZES ALL OF WHICH PASS THROUGH A U.S. STANDARD SIEVE NO. 20, AT LEAST ABOUT 85% BY WEIGHT OF WHICH PASS THROUGH A U.S. STANDARD SIEVE NO. 40 AND NOT MORE THAN ABOUT 25% BY WEIGHT OF WHICH PASS THROUGH A U.S. STANDARD SIEVE NO. 100, AND REMOVING SUBSTANTIALLY ALL WATER FROM THE RESULTING COMMINUTED NITROCELLOSE PARTICLES.