Enhanced Slag Formation For Copper-Containing Gas Generants

Abstract

Gas generants comprising copper are provided that have improved slagging ability. In certain aspects, the gas generants include a fuel, an oxidizer comprising basic copper nitrate, and a large particle size endothermic slag-forming component, such as aluminum hydroxide (Al(OH)3). The gas generants may be cool burning, e.g., having a maximum flame temperature at combustion (Tc)≤about 1,900K (1,627° C.). The disclosure also provides methods of enhancing slag formation for a gas generant composition that comprises copper. Such methods enhance slag formation during combustion of the gas generant composition by at least 50%.

1 . A method of enhancing slag formation for a cool burning gas generant composition, the method comprising:
 introducing an endothermic slag-forming component comprising aluminum hydroxide having particles with a particle size diameter of greater than 300 μm to a cool burning gas generant composition comprising a fuel and an oxidizer comprising basic copper nitrate and having a maximum flame temperature at combustion (T c ) of less than or equal to about 1,900K (1,627° C.), wherein the introducing of the endothermic slag-forming component enhances slag formation during combustion of the cool burning gas generant composition by at least 50% by forming a slag comprising aluminum oxide particles coated with a copper matrix.   
     
     
         2 . The method of  claim 1 , wherein the fuel is selected from the group consisting of: guanidine nitrate, copper bis guanylurea dinitrate, hexamine cobalt (III) nitrate, copper diammine bitetrazole, and combinations thereof. 
     
     
         3 . The method of  claim 1 , wherein the endothermic slag-forming component is present at greater than or equal to about 5% by weight to less than or equal to about 20% by weight of the total cool burning gas generant composition. 
     
     
         4 . The method of  claim 1 , wherein the introducing of the endothermic slag-forming component enhances slag formation during combustion of the cool burning gas generant composition by at least 60%. 
     
     
         5 . The method of  claim 1 , wherein the fuel is present at greater than or equal to about 25% to less than or equal to about 70% by weight of the total cool burning gas generant composition; the oxidizer is present at greater than or equal to about 25% to less than or equal to about 75% by weight of the total cool burning gas generant composition; the endothermic slag-forming component is present at greater than or equal to about 5% to less than or equal to about 20% by weight of the total cool burning gas generant composition; and greater than or equal to 0% to less than or equal to about 4% of one or more gas generant additives selected from the group consisting of: flow aids, press aids, metal oxides, and combinations thereof. 
     
     
         6 . The method of  claim 5 , further comprising a co-oxidizer comprising a perchlorate-based compound selected from a group consisting of ammonium perchlorate, sodium perchlorate, potassium perchlorate, lithium perchlorate, magnesium perchlorate and combinations thereof, present at greater than 0% to less than or equal to about 3% by weight of the total cool burning gas generant composition. 
     
     
         7 . The method of  claim 5 , wherein the cool burning gas generant composition consists essentially of: the fuel selected from the group consisting of: guanidine nitrate, copper bis guanylurea dinitrate, hexamine cobalt (III) nitrate, copper diammine bitetrazole, and combinations thereof; the oxidizer comprising basic copper nitrate; the endothermic slag-forming component comprising aluminum hydroxide; an optional co-oxidizer comprising a perchlorate-based compound; and an optional additive selected from the group consisting of: flow aids, press aids, metal oxides, and combinations thereof. 
     
     
         8 . The method of  claim 1 , wherein the cool burning gas generant composition consists essentially of the fuel comprising guanidine nitrate present at greater than or equal to about 25% to less than or equal to about 70% by weight of the total cool burning gas generant composition; the oxidizer comprising basic copper nitrate present at greater than or equal to about 25% to less than or equal to about 75% by weight of the total cool burning gas generant composition; the endothermic slag-forming component comprising aluminum hydroxide present at greater than or equal to about 5% to less than or equal to about 20% by weight of the total cool burning gas generant composition; a co-oxidizer present at greater than or equal to 0% to less than or equal to about 3% by weight of the total cool burning gas generant composition; and one or more gas generant additives present at greater than or equal to 0% to less than or equal to about 4%. 
     
     
         9 . A method of enhancing slag formation for a gas generant composition, the method comprising:
 forming a slag by combusting a cool burning gas generant composition having a maximum flame temperature at combustion (T c ) of less than or equal to about 1,500K (1,227° C.) and comprising a fuel, an oxidizer comprising basic copper nitrate, and an endothermic slag-forming component comprising aluminum hydroxide having an average particle size diameter of greater than or equal to about 200 μm, wherein the slag comprises aluminum oxide particles coated with a copper matrix.   
     
     
         10 . The method of  claim 9 , wherein the combusting occurs in an air bag inflator of a vehicle and the combusting further comprises electrically igniting a squib when rapid deceleration or a collision of the vehicle is sensed; and burning the squib to ignite the cool burning gas generant composition to generate gases passing through a filter and inflating an airbag of the air bag inflator. 
     
     
         11 . The method of  claim 10 , further comprising retaining particulates generated during the combusting of the cool burning gas generant composition as the slag in the filter, wherein a presence of the endothermic slag-forming component comprising aluminum hydroxide having the average particle size diameter of greater than or equal to about 200 μm enhances formation of the slag during combustion of the gas generant composition by at least 70% as compared to an amount of comparative particulates formed by combusting a comparative cool burning gas generant having an endothermic slag-forming component comprising aluminum hydroxide having an average particle size diameter of greater than or equal to about 150 μm. 
     
     
         12 . The method of  claim 9 , wherein the endothermic slag-forming component comprising aluminum hydroxide is present at greater than or equal to about 5% by weight to less than or equal to about 20% by weight of the total cool burning gas generant composition and the oxidizer comprising basic copper nitrate is present at greater than or equal to about 30% to less than or equal to about 70% by weight of the gas generant composition. 
     
     
         13 . The method of  claim 9 , wherein the endothermic slag-forming component comprising aluminum hydroxide having particles with a particle size diameter of greater than 300 μm. 
     
     
         14 . The method of  claim 9 , wherein the endothermic slag-forming component comprising aluminum hydroxide has a particle size distribution with 90% values of greater than or equal to about 200 μm to less than or equal to about 300 μm. 
     
     
         15 . The method of  claim 9 , wherein the fuel is selected from the group consisting of: guanidine nitrate, copper bis guanylurea dinitrate, hexamine cobalt (III) nitrate, copper diammine bitetrazole, and combinations thereof and the fuel is present at greater than or equal to about 25% to less than or equal to about 70% by weight of the total cool burning gas generant composition; the oxidizer is present at greater than or equal to about 25% to less than or equal to about 75% by weight of the total cool burning gas generant composition; the endothermic slag-forming component is present at greater than or equal to about 5% to less than or equal to about 20% by weight of the total cool burning gas generant composition; and the cool burning gas generant composition further comprises a co-oxidizer present at greater than or equal to 0% to less than or equal to about 3% by weight of the total cool burning gas generant composition; and one or more gas generant additives selected from the group consisting of: flow aids, press aids, metal oxides, and combinations thereof present at greater than or equal to 0% to less than or equal to about 4% of total cool burning gas generant composition. 
     
     
         16 . The method of  claim 15 , wherein the cool burning gas generant composition consists essentially of the fuel present at greater than or equal to about 25% to less than or equal to about 70% by weight of the total cool burning gas generant composition; the oxidizer comprising basic copper nitrate present at greater than or equal to about 25% to less than or equal to about 75% by weight of the total cool burning gas generant composition; the endothermic slag-forming component present at greater than or equal to about 5% to less than or equal to about 20% by weight of the total cool burning gas generant composition; the co-oxidizer present at greater than or equal to 0% to less than or equal to about 3% by weight of the total cool burning gas generant composition; and the one or more gas generant additives present at greater than or equal to 0% to less than or equal to about 4%. 
     
     
         17 . The method of  claim 16 , wherein the co-oxidizer comprises a perchlorate-based compound selected from a group consisting of ammonium perchlorate, sodium perchlorate, potassium perchlorate, lithium perchlorate, magnesium perchlorate and combinations thereof. 
     
     
         18 . A method of enhancing slag formation for a gas generant composition, the method comprising:
 forming a slag by combusting a cool burning gas generant composition having a maximum flame temperature at combustion (T c ) of greater than or equal to about 1,350K (1,077° C.) to less than or equal to about 1,450K (1,177° C.) and comprising a fuel comprising guanidine nitrate, an oxidizer comprising basic copper nitrate, and an endothermic slag-forming component comprising aluminum hydroxide having an average particle size diameter of greater than or equal to about 150 μm present at greater than or equal to about 5% by weight to less than or equal to about 20% of the total cool burning gas generant composition, wherein the slag comprises aluminum oxide particles coated with a copper matrix.   
     
     
         19 . The method of  claim 18 , wherein the endothermic slag-forming component comprising aluminum hydroxide having particles with a particle size diameter of greater than 300 μm. 
     
     
         20 . The method of  claim 18 , wherein the cool burning gas generant composition consists essentially of the fuel present at greater than or equal to about 25% to less than or equal to about 70% by weight of the total cool burning gas generant composition; the oxidizer present at greater than or equal to about 25% to less than or equal to about 75% by weight of the total cool burning gas generant composition; the endothermic slag-forming component present at greater than or equal to about 5% to less than or equal to about 20% by weight of the total cool burning gas generant composition; a co-oxidizer present at greater than or equal to 0% to less than or equal to about 3% by weight of the total cool burning gas generant composition, and greater than or equal to 0% to less than or equal to about 4% of one or more gas generant additives selected from the group consisting of: flow aids, press aids, metal oxides, and combinations thereof.