Slurry casting method for double base propellants

Claim 1

A process for preparation of slurry cast propellant compositions which exhibit improved burning rates, said process comprising (a) preparing an initial propellant slurry comprising a casting solvent, low viscosity nitrocellulose containing 12% nitrogen by weight, a polyol having a molecular weight of from about 2000 to about 6000 and a hydroxyl functionality of from about 2 to about 3, a polyfunctional isocyanate crosslinking agent, and solid oxidizing agents selected from organic nitramines and organic nitro compounds; (b) admixing double base casting powder granules with said propellant slurry, said casting powder granules comprising from about 10% to about 25% by weight, based on the weight of the resulting propellant slurry, said casting powder granules containing from about 20% to about 75% ammonium perchlorate having a particle size range of from about 0.5 micron to about 3.0 microns provided that if about 50% of the ammonium perchlorate in said granules has a particle size of about 0.5 micron the total perchlorate content of said casting powder shall not exceed 65% by weight; (c) casting the slurry of step (b), and (d) curing said slurry forming a crosslinked double base propellant composition.