Verfahren zur Herstellung von Nitrocellulose-Koernern niedriger Dichte

1,214,776. Nitrocellulose granules. DYNAMIT NOBEL A.G. 2 May, 1969 [4 May, 1968], No. 22628/69. Headings C3A and C3F. Nitrocellulose granules, generally having a bulk density of 0À4 to 0À6 g./cc., are prepared by adding a first quantity of a protective colloid and a water-soluble alkali metal or alkaline earth metal salt to a nitrocellulose lacquer, which has been produced by stirring nitrocellulose at a first speed in the presence of water and a solvent for nitrocellulose immiscible with water, stirring the mixture so produced at a speed of up to 60% of the first speed until the nitrocellulose lacquer forms into globules, allowing the globules to coalesce, adding a second quantity of a protective colloid and a water-soluble alkali metal or alkaline earth metal salt, increasing the stirring speed to from 60 to 95% of the first speed, allowing the lacquer to separate into globules, distilling off the solvent and collecting the nitrocellulose granules obtained. Preferably, the nitrocellulose lacquer has been produced by stirring at a first speed of 50 to 90 r.p.m. at 50‹ to 90‹ C. The nitrocellulose lacquer may contain a stabilizer such as a phthalate, urethane, methyl and/or ethyl diphenyl urea, diphenylamine or petroleum jelly. The protective colloid may be bone glue, gelatine, gum arabic or gum shiraz and the nitrocellulose solvent may be a waterinsoluble methyl, ethyl or butyl ester of a saturated C 1-5 aliphatic carboxylic acid. The salt may be any alkali metal or alkaline earth metal sulphate, chloride or nitrate, e.g. anhydrous sodium sulphate, and may be added in the form of a saturated aqueous solution. The nitrocellulose granules may be dried at 60‹ to 85‹ C. in a current of warm air. The bulk density of the nitrocellulose granules may be further reduced by a " density-lowering process," preferably carried out by treatment of the granules with water and a solution of glycerine trinitrate and/or ethylene glycol dinitrate in ethyl acetate.