GB756771A - Improvements in or relating to propellants and method of making the same - Google Patents

Abstract

756,771. Propellants. OLIN MATHIESON CHEMICAL CORPORATION. April 8, 1954 [June 9, 1953], No. 10345/54. Class 9(2) A propellant for cartridges larger than 0-30 in. is prepared by forming smokeless powder base into grains having a surface area 10-74 sq. cms. per gram, and web 0.015-0.070 in., and treating the grains with a non-migratory deterrent having a negative heat of explosion constant greater than -200 calories per grain, only in the region thereof which extends from each surface not more than 1/6th of the web of the grain. Deterrents, which may be present in amount 3-15 per cent, preferably 6-10 per cent or 9 per cent for 90 mm. propellant, may be dibutyl-, diamyl-, or diphenyl-phthalate, diethyl, methyl ethyl-, or dimethyl diphenyl urea, tricresyl or triphenyl phosphate, butyl stearate, butyl ricinoleate, or glycerol sebacate. The grains should be non-porous, i.e. have a specific gravity 1.5, and may be impregnated with 10-20 per cent liquid nitric ester of a polyhydric alcohol, e.g. nitroglycerin, befor deterrent treatment. In an example, nitrocellulose (13.2 per cent N 2 ) is suspended in water and agitated at 70‹C., after addition of ethyl acetate containing diphenylamine, until the nitrocellulose has dissolved. Agitation is continued while gum arabic dissolved in water, and then sodium sulphate dissolved in water are added, and finally solvent is removed by raising the temperature to 99 ‹C. The hardened globules are separated and suspended in water; an emulsion of nitroglycerine in ethyl acetate and water is added and the whole agitated, heated to 70‹C. and ethyl acetate removed by passing in air. An emulsion of dibutyl phthalate and gum arabic in water is added to the agitated slurry, and the grains are separated, compressed, and tumbled in a sweetie barrel with potassium nitrate, diphenyl phthalate, and dinitrotoluene, and finally with graphite. Alternatively, colloided nitrocellulose may be extruded and cut into grains. For U.5 in. cartridges the grains have surface 55-72 sq. cms./grm. and web 0.016-0.023 in. for 0.6 in. 45.60 sq. cms./grm. and 0.022-0.028 in., for 20 mm. 35-55 sq. cms./grm. and 0.025-0.032 in., and for 90mm. 32 sq. cms./grm. and 0.034 in.