GB760510A - Fire-extinguishers - Google Patents

Abstract

A fire extinguisher constructed to discharge a solid fire-extinguishing agent in finely-divided forms is filled with a fire-extinguishing agent in powder form comprising a finely-divided aldehyde-urea condensation product and a second finely-divided component consisting of one or more of the following: phosphoric acid, boric acid, their compounds and addition products with aldehyde-urea resins. The following are examples of the compositions used: (1) a urea-formaldehyde resin obtained by condensation of 1 mol. urea and 2.5 mol. formaldehyde in the form of paraformaldehyde in the presence of 1/2 mol. phosphoric acid and ground so fine that it passes through a 1600 mesh per sq. cm. screen is mixed with monoammonium phosphate of the same grain size in ratio 1:2.5; 7 per cent dextrin is added; (2) 600 gm. dicyandiamide-formaldehyde condensate is finely ground and mixed with 1200 gm. diammonium phosphate, 50 gm. boric acid and 140 gm. soluble starch and 70 gm. gypsum; (3) the mixture consists of 300 gm. dimethylene urea, 50 gm. urea orthophosphate, 350. gm. monoammonium phosphate, 75 gm. powdered asbestos and 150 gm. dextrin; (4) the resin used is that obtained by condensation of urea, paraform, and acrolein in presence of phosphoric acid; (5) 600 gm. dicyandiamide condensate, 1200 gm. diammonium phosphate, 50 gm. boric acid, 140 gm. starch and 20 gm. pyrogenically prepared silicon dioxide; (6) 100 gm. dimethylene urea, 200 gm. diammonium phosphate, 50 gm. soluble starch, 30 gm. kieselguhr; the mixture is sprayed with paraffin dissolved in benzine.