Low humidity uptake solid pyrotechnic compositions and methods for making the same

Abstract

A solid pyrotechnic composition having a flame temperature and exhibiting ballistic performance comparable to that of black powder, but which is preferably formulated to contain neither charcoal nor sulfur, is provided. A solid pyrotechnic composition having a flame temperature and exhibiting ballistic performance comparable to that of boron/potassium nitrate and that is preferably free of boron is also provided.

1 . A solid pyrotechnic composition comprising: 
 oxidizer particles comprising from about 40 weight percent to about 90 weight percent of a total weight of the solid pyrotechnic composition, the oxidizer particles comprising at least one perchlorate and having a mean particle size of not greater than about 30 microns; and    organic crystalline particles comprising from about 10 weight percent to about 60 weight percent of the total weight of the solid pyrotechnic composition;    wherein from about 20 weight percent to about 90 weight percent of the solid pyrotechnic composition comprises the at least one perchlorate.    
     
     
         2 . The solid pyrotechnic composition according to  claim 1 , wherein the at least one perchlorate comprises an alkali metal perchlorate or ammonium perchlorate.  
     
     
         3 . The solid pyrotechnic composition according to  claim 1 , further comprising at least one nitrate.  
     
     
         4 . The solid pyrotechnic composition according to  claim 3 , wherein the at least one nitrate comprises an alkali metal nitrate or ammonium nitrate.  
     
     
         5 . The solid pyrotechnic composition according to  claim 3 , wherein the oxidizer particles comprise potassium nitrate.  
     
     
         6 . The solid pyrotechnic composition according to  claim 1 , wherein the oxidizer particles comprise potassium perchlorate.  
     
     
         7 . The solid pyrotechnic composition according to  claim 1 , wherein the mean particle size of the oxidizer particles ranges from about 5 microns to about 20 microns.  
     
     
         8 . The solid pyrotechnic composition according to  claim 1 , wherein the organic crystalline particles comprise at least one member selected from the group consisting of phenolphthalein and an organic crystalline compound derived from a reaction between a phenolic compound and phthalic anhydride.  
     
     
         9 . The solid pyrotechnic composition according to  claim 1 , further comprising at least one salt of the organic crystalline particles.  
     
     
         10 . The solid pyrotechnic composition according to  claim 9 , wherein the organic crystalline particles and the at least one salt of the organic crystalline particles have a mean particle size of not greater than about 30 microns.  
     
     
         11 . The solid pyrotechnic composition according to  claim 9 , wherein the solid pyrotechnic composition has a weight ratio of the organic crystalline particles to the at least one salt of the organic crystalline particles of at least 80:20.  
     
     
         12 . The solid pyrotechnic composition according to  claim 1 , further comprising a nonhygroscopic polymeric binder, the nonhygroscopic polymeric binder having a moisture uptake of not more than 4 weight percent at 75 percent relative humidity at a temperature of 21.1° C. (70° F.) over a period of 24 hours.  
     
     
         13 . The solid pyrotechnic composition according to  claim 12 , wherein the nonhygroscopic polymeric binder comprises no more than about 10 weight percent of the total weight of the solid pyrotechnic composition.  
     
     
         14 . The solid pyrotechnic composition according to  claim 12 , wherein the nonhygroscopic polymeric binder comprises at least one member selected from the group consisting of poly(vinyl acetate), ethyl cellulose, nylon, poly(vinyl acetate-co-vinyl alcohol), poly(ethylene-co-vinyl acetate), polyethylene glycol, nitrocellulose, and chain-extended BAMO.  
     
     
         15 . The solid pyrotechnic composition according to  claim 1 , wherein the solid pyrotechnic composition is free of sulfur and charcoal.  
     
     
         16 . The solid pyrotechnic composition according to  claim 1 , wherein the solid pyrotechnic composition has a moisture uptake of not greater than 0.3 weight percent at 75 percent relative humidity at a temperature of 21.1° C. (70° F.) over a period of 24 hours.  
     
     
         17 . The solid pyrotechnic composition according to  claim 1 , wherein the solid pyrotechnic composition is formulated to have, upon ignition, a theoretical flame temperature greater than or equal to 2300K.  
     
     
         18 . A method of making a solid pyrotechnic composition comprising: 
 combining an alkali metal hydroxide with at least one organic crystalline compound to produce a solution comprising a salt of the at least one organic crystalline compound;    combining the solution with nitric acid to form alkali metal nitrate particles and to convert the salt of the at least one organic crystalline compound back to the at least one organic crystalline compound in particulate form, the alkali metal nitrate particles and the at least one organic crystalline compound in particulate form each having a mean particle size of not greater than about 30 microns; and    combining the alkali metal nitrate particles and the at least one organic crystalline compound in particulate form with additional oxidizer particles to form a pyrotechnic composition, the additional oxidizer particles having a mean particle size of not greater than about 30 microns and comprising at least one member selected from the group consisting of an alkali metal perchlorate and ammonium perchlorate;    wherein from about 40 weight percent to about 90 weight percent of a total weight of a solid pyrotechnic composition comprises the alkali metal nitrate particles and the additional oxidizer particles.    
     
     
         19 . The method according to  claim 18 , wherein combining the solution with nitric acid to form alkali metal nitrate particles comprises combining the solution with nitric acid to form potassium nitrate particles.  
     
     
         20 . The method according to  claim 18 , wherein combining the alkali metal nitrate particles and the at least one organic crystalline compound in particulate form with additional oxidizer particles comprises combining the alkali metal nitrate particles and the at least one organic crystalline compound in particulate form with potassium perchlorate.  
     
     
         21 . The method according to  claim 18 , wherein the additional oxidizer particles further comprise at least one member selected from the group consisting of an alkali metal nitrate and ammonium nitrate.  
     
     
         22 . The method according to  claim 18 , wherein combining an alkali metal hydroxide with at least one organic crystalline compound to produce a solution comprising a salt of the at least one organic crystalline compound comprises combining the alkali metal hydroxide with phenolphthalein.  
     
     
         23 . The method according to  claim 18 , wherein combining the alkali metal nitrate particles and the at least one organic crystalline compound in particulate form with additional oxidizer particles to form a pyrotechnic composition comprises forming a pyrotechnic composition that is free of the salt of the at least one organic crystalline compound.  
     
     
         24 . The method according to  claim 18 , further comprising drying the pyrotechnic composition to obtain a solid pyrotechnic composition.  
     
     
         25 . The method according to  claim 24 , wherein drying the pyrotechnic composition to obtain a solid pyrotechnic composition comprises producing a solid pyrotechnic composition that is free of sulfur and charcoal.  
     
     
         26 . The method according to  claim 18 , further comprising adding a nonhygroscopic polymeric binder to the pyrotechnic composition, the nonhygroscopic polymeric binder having a moisture uptake of not more than  4  weight percent at 75 percent relative humidity at a temperature of 21.1° C. (70° F.) over a period of 24 hours.  
     
     
         27 . A method of making a pyrotechnic composition comprising: 
 combining an alkali metal hydroxide with at least one organic crystalline compound to produce a solution comprising a salt of the at least one organic crystalline compound;    combining the solution with perchloric acid to form alkali metal perchlorate particles and to convert the salt back to the at least one organic crystalline compound in particulate form, the alkali metal perchlorate particles and the at least one organic crystalline compound in particulate form each having a mean particle size of not greater than about 30 microns; and    combining the alkali metal perchlorate particles and the at least one organic crystalline compound in particulate form with additional oxidizer particles to form a pyrotechnic composition, the additional oxidizer particles having a mean particle size of not greater than about 30 microns and comprising at least one of at least one member selected from the group consisting of alkali metal nitrate and ammonium nitrate and at least one member selected from the group consisting of alkali metal perchlorate and ammonium perchlorate;    wherein from about 40 weight percent to about 90 weight percent of a total weight of the pyrotechnic composition comprises the alkali metal perchlorate particles and the additional oxidizer particles.    
     
     
         28 . The method according to  claim 27 , wherein combining the alkali metal perchlorate particles and the at least one organic crystalline compound in particulate form with additional oxidizer particles comprises combining the alkali metal perchlorate particles and the at least one organic crystalline compound in particulate form with potassium nitrate.  
     
     
         29 . The method according to  claim 27 , wherein combining the solution with perchloric acid to form alkali metal perchlorate particles comprises combining the solution with perchloric acid to form potassium perchlorate particles.  
     
     
         30 . The method according to  claim 27 , wherein combining an alkali metal hydroxide with at least one organic crystalline compound to produce a solution comprising a salt of the at least one organic crystalline compound comprises combining the alkali metal hydroxide with phenolphthalein.  
     
     
         31 . The method according to  claim 27 , wherein combining the alkali metal perchlorate particles and the at least one organic crystalline compound in particulate form with additional oxidizer particles to form a pyrotechnic composition comprises forming a pyrotechnic composition that is free of the salt of the at least one organic crystalline compound.  
     
     
         32 . The method according to  claim 27 , further comprising drying the pyrotechnic composition to obtain a solid pyrotechnic composition.  
     
     
         33 . The method according to  claim 27 , further comprising adding a nonhygroscopic polymeric binder to the pyrotechnic composition, the nonhygroscopic polymeric binder having a moisture uptake of not more than 4 weight percent at 75 percent relative humidity at a temperature of 21.1° C. (70° F.) over a period of 24 hours.  
     
     
         34 . The method according to  claim 27 , wherein combining the alkali metal perchlorate particles and the at least one organic crystalline compound in particulate form with additional oxidizer particles to form a pyrotechnic composition comprises forming a solid pyrotechnic composition that is free of sulfur and charcoal.  
     
     
         35 . A solid pyrotechnic composition comprising: 
 oxidizer particles comprising at least one of an alkali metal nitrate and ammonium nitrate and at least one of an alkali metal perchlorate and ammonium perchlorate; and    organic crystalline particles comprising at least one of phenolphthalein, an organic crystalline compound derived from a reaction between a phenolic compound and phthalic anhydride, fluorescein, 1,5-naphthalenediol, anthraflavic acid, and terephthalic acid;    wherein the solid pyrotechnic composition is free of sulfur.    
     
     
         36 . The solid pyrotechnic composition according to  claim 35 , wherein the oxidizer particles comprise from about 40 weight percent to about 90 weight percent of a total weight of the solid pyrotechnic composition.  
     
     
         37 . The solid pyrotechnic composition according to  claim 35 , wherein the oxidizer particles have a mean particle size of not greater than about 30 microns.  
     
     
         38 . The solid pyrotechnic composition according to  claim 35 , wherein the organic crystalline particles comprise from about 10 weight percent to about 60 weight percent of a total weight of the solid pyrotechnic composition.  
     
     
         39 . The solid pyrotechnic composition according to  claim 35 , further comprising at least one nitrate.  
     
     
         40 . The solid pyrotechnic composition according to  claim 39 , wherein the at least one nitrate comprises an alkali metal nitrate or ammonium nitrate.  
     
     
         41 . The solid pyrotechnic composition according to  claim 39 , wherein the at least one nitrate comprises potassium nitrate.  
     
     
         42 . The solid pyrotechnic composition according to  claim 35 , wherein the oxidizer particles comprise potassium perchlorate.  
     
     
         43 . The solid pyrotechnic composition according to  claim 35 , further comprising at least one salt of the organic crystalline particles.  
     
     
         44 . The solid pyrotechnic composition according to  claim 43 , wherein the organic crystalline particles and the at least one salt of the organic crystalline particles comprise from about 10 weight percent to about 60 weight percent of a total weight of the solid pyrotechnic composition.  
     
     
         45 . The solid pyrotechnic composition according to  claim 43 , wherein the solid pyrotechnic composition has a weight ratio of the organic crystalline particles to the at least one salt of the organic crystalline particles of at least 80:20.  
     
     
         46 . The solid pyrotechnic composition according to  claim 35 , further comprising a nonhygroscopic polymeric binder comprising at least one member selected from the group consisting of poly(vinyl acetate), ethyl cellulose, nylon, poly(vinyl acetate-co-vinyl alcohol), poly(ethylene-co-vinyl acetate), polyethylene glycol, nitrocellulose, and chain-extended BAMO.  
     
     
         47 . The solid pyrotechnic composition according to  claim 35 , wherein the nonhygroscopic polymeric binder comprises no more than about 10 weight percent of a total weight of the solid pyrotechnic composition.  
     
     
         48 . The solid pyrotechnic composition according to  claim 35 , wherein the solid pyrotechnic composition is free of sulfur and charcoal.