MXPA00012189A - Pyrotechnic gas generant composition including high oxygen balance fuel - Google Patents

Abstract

A pyrotechnic gas generant composition includes a high oxygen balance compound or fuel, preferably, azodiformamidine dinitrate, which is the resulting reaction product of an aminoguanidine salt and nitric acid. Specifically, the high oxygen balance compound or fuel of the present invention is the resulting reaction product of aminoguanidine salts, such as aminoguanidine nitrate, aminoguanidine bicarbonate, or aminoguanidine sulfate with nitric acid. Preferably, the aminoguanidine salt is aminoguanidine bicarbonate. The resulting reaction product is a yellow precipitate that can be used alone, with or without oxidizers or other additives, for veryrapid self-deflagration or in combination with oxidizers and additives. In each instance, the gas generant composition provides both high gas output and low production of solid combustion products. Further, the precipitant is relatively non-hygroscopic and has a high burn rate. The gas generating composition is useful as a gas generator for an air bag of an occupant restraint system for an automobile, gun propellants, inflation and expulsion devices, flotation devices, pyrotechnics, fire suppression devices and smokeless, reduced smoke and smokey rocket propellants.

Description

PIROTÉCNICO GAS GENERATING COMPOSITION THAT INCLUDES A FUEL WITH A HIGH OXYGEN EQUILIBRIUM BACKGROUND OF THE INVENTION 5 1. FIELD OF THE INVENTION The present invention relates to ingredients for use in generating pyrotechnic gas compositions, and more specifically with fuel 10 containing a high oxygen balance. The gas generating compositions are useful as gas generating propellants for passenger airbag restraint systems for automobiles, gun propellants, inflation and ejection devices, flotation devices, ignition materials, pyrotechnic materials and suppression devices. of fire and smokeless rocket propellant and smoke producers.

BACKGROUND OF THE PRIOR ART There is a high demand for pyrotechnic gas generating compositions which, upon combustion, provide acceptable burn rates and provide, at relatively low flame temperatures, a high volume of substantially non-toxic gas and a low volume of material ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^ ^^^^^^^^^^^^^^ solid particulate that can produce smoke. It is also important that the solid by-products of the combustion of the gas generating compositions are minimal, and that the gaseous combustion products are substantially non-toxic and non-corrosive. In the past, various compositions of gas generators have been used in an attempt to achieve the above desirable characteristics. The US patent No. 3,405,144 discloses a 1-azido-N, N, N'-trif luorof ormamidine which is useful in a propellant composition which shows a highly specific impulse. Specifically, such material is described as being useful in compositions for rocket fuel. Gas generating compositions have also been developed that include the addition of modifiers to lower the flame temperatures and increase gas production. Moreover, ingredients may be added such as binders, auxiliary ignition, slag formers, scavengers and catalysts to improve various characteristics of the underlying propellant. Modifiers and additional ingredients very often, however, improve one aspect of the propellant composition but also contribute to the production of undesirable byproducts and can increase the corrosive condition thereof. This is particularly disadvantageous in an automobile airbag environment.

A primary gas generating composition having desirable characteristics contains strontium nitrate and aminotetrazole 5'- (SRN / 5ATZ) as main constituents. This formulation is relatively non-toxic when compared to the sodium azide systems, has good ballistic properties and retains most of the products of solid combustion such as slag or ash either in the combustion or filtration areas, for example, of an air bag system for a car . These formulations also show acceptable flame temperatures of 2523 ° C to 3023 ° C (2250-2750 ° Kelvin) depending on the stoichiometry of the formulation and the ratio of oxygen to fuel. In addition, the strontium nitrate and 5-aminotetrazole formulations are relatively non-hygroscopic and the ingredients show no crystal phase changes over the operating temperature range of the air bag system. However, such a formulation has deficiencies with respect to the gas outlet, especially in the limited volume systems 20 of a side air bag of a conductor. This is because a high concentration of strontium nitrate is required to maintain a neutral balance of oxygen with respect to fuel (0 / F). Because the designs of inflators become more and more 25 small and therefore they are in a volume more limited, propellants are required that provide greater gas output and still retain the desirable attributes of the nitrate and strontium / 5-aminotetrazole systems. Approaches have been made to obtain the attractive features of the propellants indicated above, and at the same time solve the low gas performance of the same. This has resulted in the development of propellants based on mixtures of potassium perchlorate and oxygenated fuels such as guanidine nitrate and aminoguanidine nitrate. These propellants are also relatively non-hygroscopic, provide excellent gas performance, high burn rates and only about two-thirds of the solid combustion products of the aforementioned propellants based on strontium nitrate and 5-aminotetrazole. Unfortunately, the solid combustion products do not form ash or slag which is deposited in the combustion or filtration area, instead they form very fine particulates in the gas stream which result in an exhaust gas in the form of smoke and dirty. Smoke or dirty exhaust combustion products are not commercially desirable, particularly in automobile airbag systems since the production of such a product may cause undue anxiety on the part of the drivers and passengers involved in a vehicle. car accident in which the airbags deploy. As a result, there is a need for a propellant material or a gas generator that exhibits a high gas yield upon combustion, but that does not produce unwanted byproducts in combustion.

BRIEF DESCRIPTION OF THE INVENTION The aim of the present invention is to improve and solve the deficiencies of the prior art and to provide a gas producing pyrotechnic gas producing composition substantially non-toxic and substantially non-hygroscopic which, upon combustion, produces a high gas yield and a high speed of burned with limited gaseous combustion products. Another objective of the present invention is to provide a pyrotechnic gas generating composition that includes a high oxygen balance, preferably of azodiformamidine dinitrate, which produces a high yield of desirable gas with a low combustion temperature and reduced non-gaseous combustion products. Yet another objective of the present invention is to provide a pyrotechnic gas generating composition that includes a fuel with a high oxygen balance, preferably of azodiformamidine nitrate with the self-deforming capacity similar to a solid monopropellant.

A further objective of the present invention is to provide a pyrotechnic gas generating composition that includes a fuel with a high oxygen balance which self-ignites in an inflator at acceptable temperatures but low enough to ensure that the inflator only breaks, but that do not fragment into a campfire test. Yet another objective of the present invention is to provide a gas generating composition capable of producing a substantially high gas yield upon combustion for use as a propellant for an airbag in a motor vehicle. However, the composition of the present invention can also be used to inflate systems such as an inflatable raft or a passenger escape ramp of an airplane, as well as for gun propellants, pyrotechnic games, ignition mixtures, suppression devices, etc. fire and rocket propellants. From a practical point of view, the composition of the present invention also includes additives used hitherto with other gas generating compositions, such as oxidants, gas conversion catalysts, ballistic modifiers, slag formers, ignition aids, energy plasticizers and binders, non-energetic binders and auxiliary compounds.

The foregoing objects are generally obtained by a pyrotechnic gas generating composition which includes a compound or fuel high in oxygen, preferably azodiformamidine dinitrate which is a reaction product resulting from aminoguanidine nitrate and nitric acid prepared with or without the use of permanganate of potassium Specifically, the reaction product is a yellow precipitate that can be ignited and used alone, without oxidants or other additives, for a very self-decontamination is rapidly and substantially free of smoke, or can be burned in combination with oxidants or other additives, or both. In each case, the gas generating composition provides both a high gas yield and a low production of solid decomposition products when subjected to combustion.

In addition, the precipitate is relatively non-hygroscopic and has a high burning rate. As a result, no cartridges used to contain a gas generating composition are required to withstand the extremely high pressures associated with the gas generating compositions of the Prior art, such as compositions based on ammonium nitrate, which show a similar low solid combustion product production as the gas generating composition of the present invention, but have low burn rates and are generally hygroscopic. jifc -jfe,. «Aura ja. ^ t. * 8 ~~ * BtuJim i ?? t *? , -. - •. 1- r] H nrpM |? P ??? iTO? RrBaMMia ^. ^ Aa? Ra ^ Based on the general physical characteristics of the reaction product indicated before the present invention, the product is considered to be dinitrate of 1, 1'-azodiformamidine. However, the pyrotechnic gas generating composition of the present invention is directed separately both to the use of a yellow reaction product of aminoguanidine nitrate and nitric acid and to 1,1'-azodiformamidine dinitrate. The azodiformamidine dinitrate can be formed as the reaction product of nitric acid and other salts of aminoguanidine, such as aminoguanidine bicarbonate, aminoguanidine sulfate or any combination thereof. Preferably, the aminoguanidine salt is aminoguanidine bicarbonate. The use of such materials provides an effective cost means for producing the azodiformamidine dinitrate of the present invention. The gas generating composition of the present invention is generally prepared by the methods used hitherto for the prior art compositions and generally, though not exclusively, involves the dry or wet combination and the compaction of ground ingredients that are selected for combination. In view of the advantageous characteristics of the gas generating composition of the present invention, specifically the high gas yield, the production of solid low combustion products ^^ ¡í «a ^ a < jg ^^ g | ^ at a high burn rate, generators have applications in automobile airbag systems, inflatable rafts or passenger exhaust ramps, gun propellers, pyrotechnic equipment, ignition mixtures, devices for suppression of fire and propellants for rockets. For purposes of the present invention, the term propellant or propellants and gas generator or generators are used interchangeably. In addition, for the purposes of this invention, the reactions shown are anhydrous components. However, the use of non-anhydrous components is also contemplated.

BRIEF DESCRIPTION OF THE FIGURES Figure 1 is a conventional passenger side inflator that can be used with the composition of the present invention. Figure 2 is a conventional driver's side inflator that can be used with the composition of the present invention. Figure 3 is an infrared absorption spectrum of the reaction product of mode 1 of the present invention.

Figure 4 is a differential scanning calorimetry of the reaction product of mode 1 of the present invention. Figure 5 is a differential scanning calorimetry of the reaction product of mode 2 of the present invention. Figure 6 is a differential scanning calorimetry of the reaction product of mode 3 of the present invention. Figure 7 is an infrared absorption spectrum of the reaction product of mode 1 of the present invention. Figure 8 is an infrared absorption spectrum of the reaction product of mode 2 of the present invention. Figure 9 is an infrared absorption spectrum of the reaction product of mode 3 of the present invention. Figures 10 (a) - (d) are infrared absorption spectra of the reaction product of embodiments 4, 1, 2 and 3, respectively, of the present invention. Figure 11 is an infrared absorption spectrum of the prior art for azodicarbamidine dinitrate.

Figure 12 is a graph showing the representative ignition of the reaction product of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED MODALITIES The invention provides a pyrotechnic gas generator, preferably comprising azodiformamidine dinitrate, which, when burned, provides a high gas yield and a minimum of solid combustion products which is useful for various purposes. It has been found that the reaction of a fuel with a high oxygen balance of the present invention with an oxidant produces a high gas yield volume with very few solid combustion products. In addition, the fuel, preferably azodiformamidine dinitrate, also shows a high burn rate and is a self-deflating monopropellant. As a result, the gas generating composition of the present invention can be a unique ingredient in an autoignition pill (AIP); a solid monopropellant, -a fuel with a high oxygen balance in all ignition systems; a burn-rate improver additive; and an ingredient in conventional and oxygenated hybrid inflation systems. As one can see, the gas generator of the present invention is particularly useful as an airbag propellant of an automobile, but also has applications such as gun propellant, gas generator of a flotation device, propellant, pyrotechnic material, gas generator, ignition mixture, device for suppression of fire and propellant for rockets. The additional objects and advantages of the present invention will be readily apparent to those skilled in the art from the following detailed description in which the preferred embodiments of the invention are simply shown and described by way of illustration of the best contemplated way to carry out the invention. As you will realize, the invention is capable of other different modalities and various details are capable of modifications of the various obvious aspects, all without departing from the invention. Consequently, the figures and the description should be considered as illustrative and not as limiting. More specifically, the gas generating composition of the present invention includes a formamidine type fuel with a high oxygen balance prepared from the reaction of nitric acid and aminoguanidine nitrate. The inventors consider that the fuel is going to be azodiformamidine dinitrate (also called azodicarbamidine dinitrate, azodicarbamidine dinitrate and dinitrate of a z or i or f or rmami d i na) which is shown structurally as follows: This invention, however, is not limited to solely azodiformamidine dinitrate, both crystallized and recrystallized, but instead is also directed to the product of the reaction of nitric acid and aminoguanidine nitrate as provided in detail in the following. The gas generating composition of the present invention can also be formed by the reaction of nitric acid and other aminoguanidine salts such as aminoguanidine bicarbonate (AGB) or aminoguanidine sulfate (AGS). Preferably, the aminoguanidine salt is AGB. The product of the reaction of these salts with nitric acid similarly produces a bright yellow solid material which is considered to be azodiformamidine dinitrate as indicated above, with respect to the reaction of nitric acid with aminoguanidine nitrate. With respect to azodiformamidine dinitrate, reference is made to J. Thiele, Ann 270, 39 (1892) which describes this compound as azodicarbonamidinnitra. The The previous synthesis is carried out together with a research of materials for potential fabric coloring pigments. In addition, the above synthesis involves the addition of a solution of a metal oxidizing compound (potassium permanganate) to form a yellow reaction product and does not add heat from an external source during the process. The method of the present invention, as provided in the following, is preferred because when adding heat, the reaction proceeds rapidly without the addition of a metal oxidizing compound being required. By avoiding the use of a metal oxidizing compound during the preparation of the yellow reaction product, the high oxygen fuel gas generator of the present invention can be prepared free of foreign solid minimum particles or without the potential for oxide particle formation metal. Therefore, gas generators that utilize a fuel with a high oxygen balance of the present invention can be prepared without contaminants containing metal. According to the present invention, the reaction to form azodiformamidine dinitrate will also occur without external heat and with or without the use of potassium permanganate at room temperature if the nitric acid and the aminoguanidine nitrate are allowed to digest for a period of time. of longer time. This also applies to the use of the additional salts identified above, specifically aminoguanidine bicarbonate (AGB) and aminoguanidine sulfate (AGS). Other high oxygen equilibrium fuels of hydrazodicarbonamidine, diazoguanidine, formamidine, bisformamidine and azobisformamidine as derivative fuels such as guanylylide nitrate, diazoguanidine nitrate, azobisnitroformamidine and 1, 1'-azodiformamidine dipicrate are also useful as gas generating ingredients in accordance with the present invention. In addition, they are also useful in propellant compositions to other derivatives and fuels which contain a formamidine, guanilazide, diazoguanidine or hydrazodicarbonamidine group with an oxidizing group, for example (N02), (N03), (C104), (C103), or mixtures of oxidizing groups, or mixtures of different hydrazodicarbonamidine, guanilazide, diazoguanidine, formamidine, bisformamidine and azobisformamidine with oxidizing groups with suitable precautionary measures. Propellants of the prior art, such as those containing ammonium nitrate, produce very few solid combustion products, but have many other properties that make them less desirable. For example, ammonium nitrate is hygroscopic. Further, in gas generating compositions / propellants their use results in a low burn rate and a high pressure exponent at operating pressures of 6.9-13.8 MPa (1000-2000 psi). Accordingly, a propellant composition that includes ammonium nitrate as the main oxidant must be burned at very high pressures, for example of 27.6-41.4 MPa (4000-6000 psi), and sealed to prevent moisture from contacting the composition. In addition, ammonium nitrate typically requires the use of phase stabilizers, such as potassium compounds, which generate solid combustion products. The fuel with a high oxygen balance of the present invention solves numerous characteristics indicated above, less than desirable. Specifically, a gas / propellant generating composition that includes a fuel with a high oxygen balance of the present invention shows a high gas outlet with zero or little resulting solid combustion product or ash, while also being relatively non-hygroscopic, has a high burn rate and provides a more desirable pressure exponent. As a result, the composition of the present invention does not need to be retained in a high pressure and sealed vessel when numbering, since the operating pressures desirable to obtain burn rates are much lower than for the nitrate gas generating propellant compositions. of ammonium indicated above. The gas generating composition of the present invention can function alone as a self-depleting monopropellant, as indicated above, or may include an oxidant. Other materials for processing, ignition aids, ballistic improvement, improvement of thermal standing and stability, improvement of dangerous properties, reduction of particulates, union and elimination of undesirable gaseous combustion products can be added to the composition. A single oxidant or multiple oxidants can be combined with a fuel with a high oxygen balance of the present invention to supply additional oxygen to obtain the desired balance of oxygen relative to fuel (0 / F) during combustion. Since a fuel with a high oxygen balance of the present invention includes a greater amount of oxygen compared to the above gas generating compositions, a smaller amount of oxidant is necessary to provide the desirable balance of oxygen relative to fuel (cf. / F). Suitable metal and non-metal oxidants are known in the art and generally comprise nitrites, nitrates, chlorites, chlorates, perchlorates, oxides, hydroxides, peroxides, persulfates, chromates and perchromates of non-metals, alkali metals, alkaline earth metals, transition metals and transition metal complexes and mixtures thereof. Preferred oxidants include ammonium perchlorate, potassium perchlorate, strontium nitrate, potassium nitrate, sodium nitrate, barium nitrate, potassium chlorate and mixtures thereof. ^. & Preferred oxidants are non-hygroscopic in order to preserve the advantageous characteristics of a fuel with a high oxygen balance of the present invention. Preferred oxidants are generally used in a concentration of about 0% to 98% by weight of the total gas generating composition and preferably in a concentration of 5 to 50% by weight of the total gas generating composition. The scavengers may be desirable to control the production of corrosive combustion products. For example, if a non-metallic oxidant, such as ammonium perchlorate, is used, hydrogen chloride can be produced (HCl) as a resulting reaction product, which is clearly undesirable. To avoid the production of HCl, a scavenger such as sodium nitrate can be used to form sodium chloride (NaCl) in turn. Other corrosive / toxic gas scavengers may also be used. The combustion of a fuel with a high oxygen balance of the present invention can also be controlled by the addition of ballistic modifiers and include burn speed catalysts which alter the temperature sensitivity, the pressure exposure and the speed at which the propellant is burned. Such ballistic modifiers were developed primarily for solid rocket propellants, but have also been useful in gas generators for inflatable devices. Examples of ballistic modifiers useful with the composition of the present invention include oxides such as halides of groups 4 to 12 of the periodic table of the elements (as described by IUPAC and published by CRC Press, 1989); sulfur sulfides and metal sulfides; transition metal salts containing copper, chromium, cobalt, nickel and mixtures thereof, and alkali metal and alkaline earth metal borohydrides. Ball guanidine borohydride and triaminoguanidine borohydride have also been used as ballistic modifiers. Organometallic ballistic modifiers include, but are not limited to metal chelates, oxalatoe, metallocenes, ferrocenes and acetyl acetonates of metal. Other ballistic modifiers include salts of dicyanamide, nitroguanidine, guanidine chromate, guanidine dichromate, guanidine trichromate and guanidine perchromate. The ballistic modifiers are generally used in concentrations ranging from about 0.1 to 25% by weight of the total gas generating composition. Due to the autodeflagrant and high-speed burning characteristics of the high oxygen fuel of the present invention, low concentrations of such a fuel, specifically 0.1-25%, can be incorporated for use as a ballistic modifier in other gas generating compositions.

Filterable slag formation can be improved by the addition of a slag former. However, such slag formers may not be necessary in the present invention in view of the limited amount of solid combustion product produced. If deemed necessary, suitable slag-formers include quicklime, borosilicates, vycor glasses, bentonite clay, silica, alumina, silicates, aluminates, transition metal oxides, alkaline earth compounds, lanthanide compounds, and mixtures thereof. Another additive found in the ease and temperature of ignition and the combustion resulting from the gas generating compositions is an ignition aid. Ignition aids include finely divided elemental sulfur, boron, potassium boron nitrate (BKN03), carbon, magnesium, aluminum and transition metals of group 4, transition metal oxides, hydrides and sulphides, the hydrazine salt of 3 -nitro-1, 2,4-triazol-5-one and mixtures thereof. Ignition aids are normally used in concentrations of 0.1 to 15% by weight of the total gas generating composition. It may be desirable to add compounding agents to facilitate the formation of compounds and obtain homogeneous mixtures. Suitable binders and processors or auxiliary compounds include molybdenum disulfide, graphite, boron nitride and alkali metal stearates, alkaline earth metal and transition metals, various solvents such as water, methanol, ethanol, ethyl ether, acetone, isopropanol, methylene chloride, etc., polyethylene glycols, polyacetals, polyvinyl acetates , polyvinyl alcohols, polycarbonates such as Q-PAC, cellulose acetate (CA), cellulose acetate buritate (CAB), cellulose nitrate (CN), fluoropolymers commercially available under the trade name TEFLON and silicones. The compounding auxiliaries typically, but not universally, used in concentrations of about 0.1 to 15% by weight of the total gas generating composition. In addition to the additives indicated above, the fuel with a high balance of the present invention can also be combined with other fuels and / or nitro energy substances and / or nitrate plasticizers and / or binder energetic and non-energetic to provide a generating composition of gas / propellant. Suitable fuels for such combination with the fuel of the present invention include but are not limited to azido, hydrazine guanidine, tetrazole, triazole, triazine, polyamine, nitramine families. (linear and cyclic) and derivatives of these fuel families, as well as mixtures thereof. Suitable energy plasticizers include, but are not limited to butanotriol trinitrate (BTTN), nitroglycerin (NG), triethylene glycol dinitrate (TEGDN), trimethylolethane trinitrate (TMETN) and mixtures thereof. An example of an energy binder includes glycidylazyl (GAP) polymer. The manner and order in which the components of the gas generating composition of the present invention combine and form compounds are not critical insofar as an intimate and uniform mixture with good structural integrity is obtained and the formation of compounds is carried out. carried out under conditions which are not unduly dangerous and which do not cause decomposition of the components used. For example, the materials can be combined in number in aqueous or non-aqueous liquids, or they can be combined in dry, with or without the binders or processing aids, in a ball mill or in a paint mixer of the "RED DEVIL" type. "and then they can be extruded, granulated by compression molding or they can be formed into monolithic grains that can be emptied or molded by compression. The materials can also be ground separately or together with and without binders and / or other additives in a fluid energy mill, a "S ECO" vibro-energy mill, or in a bantam micropulverizer and can then be combined or further combined in a combiner v before its compaction.

The various components described above for use with the novel high oxygen balance fuel of the present invention have been used hitherto in other gas generating compositions. Gas generating compositions involving references describing various additives include US patents. Nos. 5,035,757; 5,084,118; 5,139,588; 4,948,439; 4,909,549; and 4,370,181. As described in this technique and as will be apparent to those skilled in the art, it is possible to combine the functions of two or more additives into a single composition. Therefore, the alkaline earth metal salts of tetrazoles, bitetrazoles and triazoles not only function as gas generating components but can also be used as slag formers. It has also been found that strontium nitrate acts not only as an oxidant and a slag former, but is also effective as a ballistic modifier, ignition aid, densifier and processing aid. The fuel with a high oxygen balance of the present invention can utilize conventional gas generating mechanisms of the prior art. These are mentioned in the US patent. No. 4,369,079, incorporated herein by reference. Generally, the methods of the prior art involve the use of a hermetically sealed metallic cartridge containing a gas generating composition. The hydrazodicarbonamidine, diazoguanidine, formamidine, bisformamidine and azobisformamidine type fuels of the present invention can be used in such devices. Specifically, upon initiation of combustion by firing a detonator, the sealed mechanism is broken. This allows gas to flow out of the combustion chamber through several holes. Of course, other gas generating mechanisms can also be used for use with the gas generating composition of the present invention. With reference to an automobile airbag environment, Figure 1 shows a conventional passenger side hybrid inflator, for a car in which the high oxygen balance fuel of the present invention can be used. In practice, the initiator 1 is turned on in response to a detector (not shown) that detects a rapid deceleration indicative of a collision. The initiator releases hot gases that ignite the ignition charge 2 which causes the main generating charge 8 to ignite, so that the inflation gas mixture 3 is heated and further pressurized. When the pressure in the inflation gas mixture is increased to some extent, the seal disc 6 is broken, which allows the gas mixture to exit the manifold 4 through the outlet portions 5 and inflate an air bag . The generator container 9 maintains the main generator load. All the charges in the inflation gas mixture are enclosed in the pressure tank 7. Figure 2 illustrates a pyrotechnic gas generator in which the present invention can be used. Since there is no part of the inflator reserved for storage capacity, the device is smaller than its hybrid inflator counterpart. In this figure, there is an initiator 11 that will turn on in response to a signal from a detector (not shown), which generates a signal as a result of a change in conditions, for example, an excessive increase in temperature or a sudden deceleration of m vehicle (indicative of a crash) in which the inflator is installed. The initiator 11 releases hot gases that ignite the main generating load 16, which is burned and generating an inflation gas mixture. The mixture leaves the manifold 14 through the outlet orifices 15. To ensure that the gas generator propellant 16 is turned on well below its autognition temperature (Tg) and well below the temperature at which the building materials of the physical elements begin to weaken, a self-induction propellant (AIP) 13 will have a suitably low Tg which may be necessary to ignite the ignition charge 12, which then ignites the propellant 16. Due to the high burn rates exhibited by the high oxygen balance fuel of the present invention a Moderate to low operating pressures, the invention can also be used in the physical form of a monolithic grain. The use of the fuel with a high oxygen balance of the present invention desirably provides the autodeflagration capability similar to that of a solid monopropellant. Furthermore, the fuel with a high oxygen balance of the present invention allows the use of much lower concentrations of oxidizing components and results in a much lower concentration of solid combustion products and higher gas yield, which is particularly advantageous for fuel systems. limited volume. As a result, the fuel with a high oxygen balance of the present invention has applications both in the systems set forth above and which are generally illustrated in Figures 1 and 2. Although the yellow solid product of the nitrate reaction of aminoguanidine and nitric acid, as well as the yellow solid reaction product of nitric acid and other aminoguanidine salts, such as aminoguanidine bicarbonate or aminoguanidine sulfates, or both, are presumed to be azobisformamidine dinitrate (azobisformamidine dinitrate) , this invention is not limited solely to this specific high oxygen balance fuel. The invention also specifically addresses azodiformamidine dinitrate (azobisformamidine dinitrate). However, for simplicity of use, the term "AZODN" below refers to both the anhydrous and hydrous versions of azodiformamidine dinitrate reaction product, unless specifically indicated otherwise. Similar results can also be obtained by the use of azodiformamidine dinitrate from the reaction of nitric acid and aminoguanidine bicarbonate or aminoguanidine sulfate or both. A comparison of the fuel with a high oxygen balance of the present invention, specifically, AZODN, with other fuels with a high oxygen balance (HOB and CAPS), shows that AZODN has a higher oxygen balance with respect to carbon dioxide and water compared to other fuels with high oxygen balance, as indicated in Table 1.

TABLE 1 Balance of oxygen with respect to CO, and H20 for HOB fuels Compound Oxygen balance for CO, and H, 0 Azobisformamidine dinitrate (AODN), C2H8N806 -13.3% jjig Ethylenediamine dinitrate (EDDN), C2H10N4O6 -25.8% Guanidine nitrate (GN), CH6N403 -26.2% A better oxygen balance of AZODN of the present invention over the other high oxygen balance fuels, such as guanidine nitrate, allows the use of a lower concentration of oxidant to maintain a desired balance of 0.90 / 1 to 1.1 / 1 of oxygen relative to fuel (0 / F) in a resulting gas generating composition. However, if a generator that is totally or essentially free of a solid combustion product is desired, an oxidant, such as any stabilized phase or an unstabilized ammonium nitrate in terms of phase, can be used with a fuel with an equilibrium high oxygen of the present invention. In such a case, the fuel of the present invention must be present in 40-60% by weight of the total gas generating composition. The use of AZODN of the present invention either in the form of the reaction product of aminoguanidine nitrate and nitric acid or, specifically, of azobisformamidine dinitrate, produces higher gas yields and fewer solid combustion products. As provided in Table 2 below, prior art fuels, such as 5-aminotetrazole (5ATZ) (discussed earlier in the background of the invention), guanidine nitrate (GN) and ethylenediamine dinitrate (EDDN), * * * Samai &Bi * nz2S ^ a. - • * "». - p ^ -, .- ». - -» A- »> ^. ^ Faith« requires a greater quantity of strontium nitrate (SrN) in order to achieve a balance of 0.95 / 1 In addition, gas generating compositions that include these fuels produce less gas yield and more solid combustion products compared to the gas generating compositions including AZODN of the present invention.

TABLE 2 Comparison of fuels with a high oxygen balance (HOB) with SrN * Fuel SrN / Fuel Temperature Performance Products of solid gas flame AZODN 21.8 / 78.2 2734 32.4 12.5 EDDN 36.5 / 63.5 2546 32.4 17.9 GN 37.5 / 62.5 2236 30.6 21.6 5ATZ 37.9 / 62 1 2700 24.8 31.2 O / F = 0.95 / 1 As shown by the solutions set forth in Table 2, the compositions including EDDN, GN and 5ATZ require more than 10% by weight of SrN than the composition that includes a fuel with an alt.o equilibrium. of oxygen (AZODN) of the present invention to provide the ratio of 0.95 / 1 of 0 / F. Although 5ATZ shows a similar flame temperature as in the present invention, the lower significant gas output and the content of solid combustion products is more than twice as high for the composition including 5ATZ as compared to the composition including AZODN. An adaptation of the balitic is anticipated, a partial substitution of potassium perchlorate (KP) with strontium nitrate can be carried out. Under these conditions, the formation of solid combustion products decreases even more, as indicated in Table 3.

TABLE 3 Partial replacement of KP by SrN with HOB fuels Fuel SrN / TP / Fuel Temperature Output Products of the flare (K) of solid gas AZODN 10.0 / 10.2 / 79.8 2792 32.9 11.2 EDDN 17.1 / 17.1 / 65.8 2615 32.6 17.6 GN 17.6 / 17.6 / 64.8 2304 32.7 18.1 * a ^^ faith * ^ jjij ^ "^ S8í ^^ j ^^^^ gÉ '^' j ^ ¡¡¡¡¡¡¡jjj.

However, even compositions that include EDDN and GN as fuel, require significantly more potassium perchlorate and strontium nitrate compared to the composition that includes AZODN. Although the gas performance for all of the three previous compositions are similar to each other, the production of solid combustion products for the composition used by AZODN is much lower. Accordingly, the gas generator of the present invention including AZODN is preferred for gas pyrotechnic generating systems as illustrated in Figures 1 and 2. Compositions that include a fuel with a high oxygen balance of the present invention (AZODN) and the oxidants given below in Tables 4-7 to carry out the desired 0 / F equilibrium of 0.90 / 1 to ll / L. Specifically, compositions including AZODN and ammonium nitrate (AN) are provided in Table 4.; and:? Table 5 provides AZODN, ammonium perchlorate (AP) and strontium nitrate (SrN); Table 6 provides AZODN, ammonium perchlorate (AP) and sodium nitrate (SN); and Table 7 provides AZODN, amoebic perchlorate (AP) and potassium nitrate (KN). It should be noted that although the compositions of Table 4 are hygroscopic, the production of the solid combustion products is still very small. In addition, the use of phase-stabilized ammonium nitrate is preferred.

TABLE 4 Compositions of AZODN and nitrate of a oino AZODN (% by weight) AN (% by weight) Balance 0 / F 75 23 0.9 / 1 67.35 32.65 0.95 / 1 60 40 1.0 / 1 52.94 47.06 1.05 / 1 46.15 53.85 l.l / l TABLE 5 Compositions of AZODN, ammonium perchlorate and strontium nitrate AZODN (% by weight) AP (% by weight) SrN Balance 0 / F 82. 3 9.3 8.4 0.9 / 1 77.4 11.9 10.7 0.95 / 1 72.9 14.3 12.8 1.0 / 1 69.2 16.5 14.3 1.05 / 1 64.8 18.5 16.7 1.1 / 1 TABLE 6 Compositions of AZODN, ammonium perchlorate and sodium nitrate AZODN (% by weight) AP (% by weight) SN Balance 0 / I; 83. 7 9.5 6.8 0.9 / 1 79.1 12.1 8.8 0.95 / 1 74.8 14.6 10.6 1.0 / 1 70.8 16.9 12.3 1.05 / 1 67.0 19.1 13.9 1.1 / 1 TABLE 7 Compositions of AZODN, ammonium perchlorate and potassium nitrate AZODN (% by weight) AP (% by weight) SN Balance 0/1 82. 6 9.3 8.1 0.9 / 1 77.8 11.9 10.3 0.95 / 1 77.3 14.3 12.4 1.0 / 1 69.2 16.5 14.3 1.05 / 1 65.3 18.6 16.1 1.1 / 1 In order to better understand the function of combustion with an equilibrium the evade of the present invention, the theoretical reaction examples of AZODN of the present invention are given below, wherein the structural formula for AZODN is as follows : and the molecular formula is C2HßNs06 (1) Pure AZQDN as a monopropellant for use in hybrid or ignition systems C2HßNß06 - > 4H20 + 2C0 + 4N2 240 72 56 112 = 240 100.0% 30.0% 23.33% 46.67% 1.667 M 0.833 M 1.667 M Total gas yield: 100.0% by weight Total gas yield (moles): 4.167 mol / 100 g Total solid combustion products: Zero% by weight (2) AZODN with ammonium nitrate (normal or stabilized phase): 2C2H8N8O6 + 3NH4NO3- > 14H2O + 3CO2 + CO + 11N, 480 240 252 132 28 308 = 720 66.67% 33.33% 35.00% 18.33% 3.89% 42.78% 1.944M 0.417M 0.139M 1.528M B6É * B ^ ^ & ¿B & M ** - ^ ~ - ~ > m? Mk * e? * ai? ^^ = 2 ^ L & amp; z & amp; amp; amp; amp; amp; Total gas yield: 100.0% by weight (O / F = 1.00) 100.0% by weight (O / F = 0.95) Total gas yield (moles) 4.04 moles / 100 g Total solid combustion products: Zero% by weight (3) AZODN with lithium nitrate and ammonium perchlorate: 5C2H "NgO6 + 2LiNO3 + 2NH4ClO4- > 2LIC1 + 24H2O + 10CO2 + 22N, 1200 138 234 84 432 440 616 = 1572 76. 33% 8.78% 14.89% 5.34% 27.48% 27.99% 39 19% 0.127M 1.53M 0.636M 39.19M Total gas yield: 94.7% by weight (O / F = 1.00) 95.6% by weight (O / F = 0.95) Total gas yield (moles): 3.69 moles / 100 g Total solid combustion products: 5.3% by weight (O / F = 1.00) 4.4% by weight (O / F = 0.95) (4) AZODN with sodium nitrate and ammonium perchlorate: 5C2H8N8O6 + 2NaNO, + 2NH4ClO4- > 2NaCl + 24H, O + 10CO, + 22N, 1200 170 234 116 432 440 616 = 1604 74.81% 10.60% 14.59% 7.23% 26 93% 27.43% 38.41% 0.125M 1.50M 0.623M 1.372M Total gas yield: 92.8% by weight (O / F = 1.00) 93.8% by weight (O / F = 0.95) Total gas yield (moles): 3.50 moles / 100 g Total solid combustion products: 7.2% by weight (O / F = 1.00) 6.2% by weight (O / F = 0.95) (5) AZODN with potassium nitrate and ammonium perchlorate: 5C2H8N8O6 + 2KNO3 + 2NH4ClO4- > 2KC1 + 24H2O + 10CO2 + 22N, 1200 202 234 148 432 440 616 = 1636 73.35% 12.35% 14.30% 9.05% 26.41% 26.89% 37 65% 0.122M 1.467M 0.61 1M 1345M Total gas yield: 91.0% by weight (O / F = 1.00) 92.0% by weight (OF = 0.95) Total gas yield (moles): 3.42 moles / 100 g Total solid combustion products: 9.0% by weight (O / F = 1.00) 8.0% by weight (O / F = 0.95) (6) AZODN with strontium nitrate and ammonium perchlorate. 5C2H8N8O6 + Sr (NO3) 2 + 2NH4ClO4- > SrCl2 + 24H2O + 10CO2 + 22N2 1200 212 234 157 432 440 616 = 1645 72. 90% 12.89% 14.21% 9.54% 26.26% 26.75% 37.45% 0.061M 1.459M 0.608M 1.338M Total gas yield: 90.5% by weight (O / F = 1.00) 92.0% by weight (O / F = 0.95) Performance Total gas (moles): 3.405 moles / 100 g Total solid combustion products: 9.5% by weight (OF = 1.00) 8.0% by weight (O / F = 0.95) (7) AZODN with lithium carbonate and ammonium perchlorate coolant: 14C2H8N8O6 + 9NH4ClO4 + 5Li2CO3- > 9LiCl + '/ 2Li2O + 27CO2 + 6CO + óOil ^ + ViO, 3360 1053 370 378 15 1332 1 188 168 1694 8 = 4783 70.25% 22.01% 7.74% 7.90% 0.31% 27.85% 24 84% 3.51% 35.42% 0. 17% 0.188M 0.010M 1.547M 0.565M 0.125M 1.265M 0. 005M.

Total gas yield: 91.79% by weight (O / F = 1.00) - ^ tr, a? s? ^? á? é? ^ ííAi ^ - 92.00% by weight (O / F = 0.95) Total gas yield (moles): 3.51 mol / 100 g 3.73 mol / 100 g Products of total solid combustion: 8.20% by weight (O / F = 1.00) 8.00% by weight (O / F = 0.95) (8) AZODN with scandium nitrate and ammonium perchlorate: 2C2H8N8O6 + 1 / 3Sc (NO3) 3 +% NH4ClO4- > 1 / 3ScCl2 + 9y3H20 + 4CO, + 9N, + 1 / 6O, 480 77 78 38 167.4 176 251 2.6 = 635 75.59% 12.13% 12.28% 5.98% 26.36% 27.72% 39.53% 0.41% 0.05M 1 46M 0.63M 1.41% 0.01M Total gas yield: 94.0% by weight (O / F = 1.00) 3.51% moles / 100 g (O / F = 1 00) Total solid combustion products: 6.0% by weight (O / F = 1.00) (9) AZODN with sodium nitrate: 5C, F NsO? + 4NaNO, - > 2Na2O + 20H20 + 10CO2 + 22N2 1200 340 124 360 440 616 = 1540 77.92% 22.08% 8.05% 23.38% 28.57% 40.00% 0.130M 1.299M 0.649M 1 429M Total gas yield: 92.0% by weight (O / F = 1.00 ) 93.0% by weight (O / F = 0.95) Total gas yield (moles): 3.38% moles / 100 grams Total solid combustion products: 8.0% by weight (O / F = 1.00) 7.00% by weight (O / F = 0.95) (10) AZODN with strontium nitrate: 5C2H8N8O6 + 2Sr (NO3) 2 ... > 2SrO + 20H20 + 10CO2 + 22N2 1200 424 208 360 440 616 = 1624 73.89% 26.1 1% _ 12.81% 22.17% 27.09% 37.93% 0.123M 1.232M 0.616M 1.355M Total gas yield: 87.2% by weight (O / F) = 1.00) 89.3% by weight (O / F = 0.95) Total gas yield (moles): 3.20% moles / 100 grams Total solid combustion products: 12.8% by weight (O / F = 1.00) . 7% by weight (O / F = 0.95) (1 1) AZODN with potassium perchlorate: 2C2H8N8O6 + KClO4 - > KCl + 8H2O + 4CO2 + 8N2 480 138 74 144 176 224 = 618 77. 67% 22.33% 1 1.97% 23.30% 28.48% 36.25% 0.162M 1.294M 0.647M 1.295 Total gas yield: 88.03% by weight (O / F = 1.00) 89.90% by weight (O / F = 0.95) Gas yield total (moles): 3.24% moles / 100 grams 3.56 moles / 100 grams Total solid combustion products: 11.97% (O / F = 1.00) 10.10% (O / F = 0.95) (12) AZODN with aminoguanidine hexanitratocerate CeC2H12NI4O18 + 3C2H8NsO6 - > CeO2 + 18H2O + 8CO2 + 19N2 660 720 172 324 352 532 = 1380 47. 82% 52.18% 12.46% 23.48% 25.51% 38.55% = 100% Total gas yield: 87.54% Total solid combustion products: 12.46% (13) AZODN with aminoguanidine hexanitratroscandate: ScC2H12N14O18 + 3C2H8N8O6 - > ScO2 + 18H2O + 8CO, + 19N2 565 720 77 324 352 532 = 1285 43. 97% 56.03% 5.99% 25.21% 27.39% 41.40% = 100% Total gas yield: 94.01% Total solid combustion products: 5.99% As provided by the AZODN theoretical reactions, a substantial gas yield is possible by utilizing the fuel of the present invention. In most cases, the gas yield is greater than 90% by weight. Even at a higher level of solid combustion products formed, the gas generator of the present invention using AZODN produces fewer products of; solid combustion compared to the compositions; gas generators of the prior art.

The specific process for obtaining the reaction product resulting from the present invention from the reaction of aminoguanidine nitrate and nitric acid is provided in the following. In addition, the use of this resulting reaction product with various additives is also provided to demonstrate the advantageous features thereof. Accordingly, the term AZODN, as used in Examples 1-12 which are provided in the following, refers to the actual yellow precipitate of Example 1. As indicated above, the reaction product of nitric acid and other salts of aminoguanidine, such as aminoguanidine bicarbonate or aminoguanidine sulfate, can provide substantially the same results as the AZODN used in the following examples. This is supported by additional tests carried out to demonstrate that the product resulting from the reaction of nitric acid and these additional salts have the same characteristics as the AZODN of Example 1.

Example 1 The fuel with a high oxygen balance of the present invention is prepared by the following method. First, weigh 10 grams of aminoguanidine nitrate (AGN) in a 400 ml glass flask. Then water, preferably distilled, is added to a volume of approximately ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 20-25 mi, and you get a suspension of AGN / water. A dispersion is formed by slowly pouring 150 ml of reactive grade nitric acid (70%), while stirring, into the AGN / water suspension, which leads to a total volume of about 170/175 ml. A temperature increase of 10 degrees is presented as the acid is added for the first time. By continuously adding the acid, the temperature goes down again. The dispersion is then heated to 55-65 ° C with moderate agitation on a hot plate. This causes any remnant AGN to be in solution. Heating is continued at 55-65 ° C, during which time the solution undergoes a color transition from a water white color to a straw color and an intense bright yellow color (reminiscent of the color of a potassium dichromate solution) . [It is recommended to use a bell and a ready ice bath]. In addition, the reaction should be limited to a maximum temperature below 65 ° C. It should be noted that the solution will change to a deeper yellow color just before the exotherm. The beaker is then placed in an ice bath to cool the contents and allow effervescence to disappear. A yellow precipitate appears as the temperature decreases below 12 ° C after the reaction mixture is kept in the ice bath for about 0-5 ° C. The yellow precipitate is filtered under vacuum and washed with several rinses of distilled water. The precipitate is then washed several times with ethanol and then dried at 62 ° C.

Example 2 The infrared absorption spectra are determined for the reaction product formed from the procedure set forth in Example 1 and are given in Figure 3. The absorption spectra are compared to the infrared absorption spectra of azodicarbamidine dinitrate which is found in the literature, Anal. Chem. 23, 1594 (1951). A comparison of figure 3 with the reference spectra (Figure 11) shows that the azobisformamidine-like reaction product synthesized of the present invention is considered to be 1,1'-azodiformamidine dinitrate (azodicarbamidine dinitrate).

Example 3 Differential scanning calorimetry is used (DSC) to compare the thermal stability of a washed reaction product of example 1 and a thermally aged reaction product (17 days at 107 ° C). The DSC graphs for the washed reaction product and the reaction product that has been left to stand thermally show that the aging changes only slightly the exothermic peak of the material and the start of the exotherm of the material. Specifically, the start of the exotherm changes from 160.82 ° C to 170.21 ° C, and the exothermic peak changes from 183.32 ° C to 185.45 ° C. Accordingly, the AZODN fuel of the present invention exhibits good aging characteristics.

E-example 4 A powder of pure AZODN, produced by the method of Example 1, which does not contain oxidants or other additives, autodeflagrante very quickly when it is turned on under conditions of temperature and ambient pressure. Specifically, a small amount (1/2 gram) of the fuel with a high oxygen balance of Example 1 is placed in a pile in the center of a watch glass and the flame of a burning ferrule is placed on the sample. The sample immediately ignites and burns very quickly and in a clean manner, similar to the gunpowder of a smokeless rifle. Such rapid autodeflagration returns to the fuel AZODN of the present invention beneficial for the use of heterogeneous and / or hybrids or autoignition pills (AIP's), and all the pyrotechnic gas generating systems.

Example 5 An amount of 0.269 grams of AZODN of the present invention is placed in a pre-weighed aluminum tray and ignited with a burning splint. The tray is reweighed after the ignition. From the initial reaction product of AZODN, 0.005 grams of a cinnamon residue remain, which leaves a residual burn of 1.84% by weight. Additional tests are performed on small batches of propellant contained in the AZODN reaction product of the present invention to determine sensitivity, thermal aging, weight loss and ballistic properties. The density of the product and the propellants made from the product is determined from the measurements of weight and dimensions of the granules which is 1.66 g / cc or greater.

Example 6 When pressed granules are burned to a size of 6. 4 mm x 16 mm (1/4 inch x 5/8 inches) of pure AZODN of the present invention in a chain pump, without any oxidants or other additives, show burning rates of 3.1, 8.7 and 10.9 mm / sec ( 0.122, 0.342 and 0.428 inches per second (ips)) at 0.60, 3.45 and 5.17 MPa (100, 500 and 750 psi), respectively. These speeds provide an exponent burn rate of 0.63.

Example 7 A propellant (batch # 11899) containing sodium nitrate (SN) 10.60% as an oxidant and scavenger, ammonium perchlorate (AP) 14.59%, and AZODN 74.81% of the present invention is formulated in an O / F ratio of 1.0 to provide, when burned, 7% of solid combustion products and 3.7 moles of substantially non-toxic gas per 100 grams of composition product. This formulation provides burn rates of 8 and 12 mm / sec (0.32 and 0.46 ips), respectively, at 3.45 and 5.17 MPa (500 and 750 psi). These velocities provide a pressure exponent of 0.90.

Example 8 Another propellant (lot # 11900) containing oxidant of sodium nitrate (SN) 22.05% and AZODN 77.92% of the present invention is formulated to provide, when burning levels of solid combustion products of 8% and 3.4 moles of gas substantially non-toxic per 100 grams of composition When testing 6.4 mm x 16 mm (1/4 x 5/8 inch) granules to determine ballistic properties, the burn properties at 1.72, 3.45, 5.17, 6.89 and 8.62 MPa ( 250, 500, 750, 1000 and 1250 psi) were, respectively, of 4.3, 8.1, 11.9, 15.0 and 18.5 mm / sec (0.17, 0.32, 0.47, 0.59 and 0.73 ips). These values provide a pressure exponent of 0.90. 9 Another propellant (batch # 11901) containing lithium carbonate (LC) eliminator 7.74% and refrigerant, AP oxidant 22.01% and AZODN 70.25% of the present invention provides a burn rate of 8.6 m / s (0.34 ips) to 3.44. MPa (500 psi), but suffers from a serious weight loss of 5.9% after 24 hours at 107 ° C. The DSC for this formulation provides an initial temperature of 146 ° C and a peak of exotherm at 179 ° C.

Example 10 A propellant (lot # 11903) containing per hundred weight of potassium nitrate (KN) of 12.35% that acts as a scavenger / oxidant, ammonium perchlorate (AP), 14.3%, and AZODN 73. 35% of the present invention is formulated in an O / F ratio of 1.0 to provide in combustion a level of theoretical solid combustion products of 9% and 3.6 moles of a substantially non-toxic gas per 100 grams of composition. When pressed in granules of 6.3 x 15.8 mm (1/4 x 5/8 inches) and tested for ballistic properties, the formulation provides a burn rate of 10 and 13 mm / sec (0.40 and 0.52 ips) to 3.4 and 5.2 MPa (500 and 750 psi) respectively, with a pressure exponent of 0.56.

Example 11 Another propellant (batch # 11905) is formulated containing strontium nitrate (SrN) 12.89%, AP 14.21% and AZODN 72.90% of the present invention (with SrN acting as an ash agent / scavenger / oxidant) in an O / ratio F of 1.0 to provide, when burned, a solid decomposition product level of 9.5%, resulting in 3.5 moles of substantially non-toxic gas per 100 grams of composition. This mixture provides a burn rate of 8.6 and 15.5 mm / sec (0.34 and 0.61 ips) at 3.4 and 6.9 MPa (500 and 1000 psi) with a pressure exponent of 0.85. The starting temperatures and the exothermic peaks for the various propellant mixtures given above are indicated in Table 8. These temperatures are obtained from DSC graphs that are carried out for each of the batches indicated above.

TABLE 8 Exothermic peak temperatures and observed start of exotherms, via DSC Lot Component Composition Home Maximum (% by weight) CC) CC) Pure AZODN 100 161 183 B11899 AZODN 74.8 158 182 SN 10.6 AP 14.6 B11900 AZODN 77.9 158 181 SN 22.1 B11901 AZODN 70.3 146 179 LC 7.7 AP 22.0 B11903 AZODN 73.35 157 183 KN 12.35 AP 14.3 B11905 AZODN 72.9 160 184.5 SrN 12.9 AP 14.2 Pressurized burn rates of the above examples of the AZODN propellants are given below in Table 9.

TABLE 9 Pressurized burn rates for propellants AZODN Burning speed Exponent Inches per second at one pressure (Psia) Lot of pressure 100 250 500 750 1000 1250 Pure AZODN 0 63 0.12 0 34 0.43 B1 1899 0.90 0.32 0 46 B11900 0.90 0.17 0.32 0 47 0.59 0 73 B11903 0.56 0 40 0 52 B11905 0.85 0.34 0.61 Weight loss during aging is presented in Table 10 for various AZODN formulations given above.

TABLE 10 Loss of weight of granules vs. days at temperature Cumulative weight loss at a temperature of Days at 90 ° C 107 ° C Lot temperature m AZODN pure 1 0.16 0.60 3 0.41 1.09 7 0.58 1.48 13 0.64 1.65 25 0.87 1.79 B1 1899 1 0.27 0.54 2 0.57 0.83 3 0 62 0.98 7 0.88 1.30 16 1 08 1.66 B11903 1 0.27 0.44 2 0.39 0.62 3 0.44 0.66 7 0.61 0.96 16 0.74 1.16 B11905 1 0.23 0.43 2 0.36 0.61 3 0.42 0.78 7 0.60 1.11 16 0.78 1.43 Each of the previous examples used AZODN filtered, washed and dried, but not recrystallized. Table 10 shows that very little weight is lost during accelerated aging at 107 and 90 ° C. The granules (13 mm (1/2 inch) in diameter x 13 mm (1/2 inch) in height) are dried at 62 ° 2 (without vacuum) before placing them in an aging oven.

Some weight loss occurs during the first day (2 hours) and is probably due to volatile aqueous or non-aqueous content.

Example 12 The reformulation of the previous propellant batches in a 0 / F ratio of 0.90 and 0.95 results in levels of solid combustion products in a range of 6 to 7.5%. The replacement of SN by a KN scavenger and an oxidant in the AP / AZODN systems (where the scavenger inhibits or eliminates, or both, the formation of hydrogen chloride) results in levels of solid combustion products of 6 and 4.5% in 0 / F ratios of 0.95 and 0.90, respectively. All batches of propellant using a fuel with a high oxygen balance of the present invention, as well as pure AZODN, when tested, respond with acceptable hazard properties with respect to impact, friction and electrostatic sensitivity performed on the powders. All propellant initial impact tests show 10 negatives at 2.0 kg to 50 cm (100 kg-cm). Subsequent tests with drier ingredients indicate acceptable hazard properties. However, the impact test values for these subsequent tests indicate a slightly higher sensitivity, for example 50 kg-cm. All electrostatic discharge tests show 10 negatives at six joules and 5kV. All friction tests (type ABL) show 10 negatives at 2.1 MPa (300 psi) -90 ° C with propellants LC, SN and KN * $ Ssa & s ¡, _. «^ Gjafe« < AA (see examples below) showing 10 negatives at 12.4 MPa (1800 psi) -90 ° C. Thermal stability studies, which include differential scanning calorimetry (DSC) and accelerated aging at elevated temperatures, are carried out in several batches containing a product with a high oxygen balance that is considered to be AZODN prepared according to the Example 1. A DSC graph of a propellant containing respectively 12.9, 14.2 and 72.9 in percentages by weight of strontium nitrate (SrN), ammonium perchlorate (AP) and non-recrystallized AZODN, shows an exothermic onset which occurs at 161 ° C with a decomposition higher at 184.5 ° C. Differential scanning calorimetry (DSC) indicates the onset of exothermic decomposition which is approximately 160 ° C for all of the above propellants. This suggests that an autoignition pill (AIP) with propellants containing a high oxygen balance fuel of the present invention or AZODN may not be necessary. Since pure AZODN and propellants containing AZODN possess low but acceptable autoignition temperatures and acceptable pressure exponents combined with high burn rates at low operating pressures, this invention will be very effective to use physical elements inflator of limited volume and of reduced weight.

In addition, if manufactured from aluminum, high-performance plastics or low-caliber steel components, the operation of an inflator using the propellants of the present invention is more likely to pass fire tests than those required by an inflator to downloads without fragmentation Example 13 The fuel with a high oxygen balance of the present invention is prepared by the method of example 1, but instead of aminoguanidine nitrate, aminoguanidine bicarbonate is combined with nitric acid to provide a fuel mode 2. with a high oxygen balance of the present invention.

Example 14 The fuel with a high oxygen balance of the present invention is prepared by the method of example 1, but, instead of aminoguanidine nitrate, aminoguanidine sulfate is combined with nitric acid to provide a mode 3 of a fuel with a high equilibrium of oxygen of the present invention.

Example 15 The fuel with a high oxygen balance of the present invention is prepared by the method of example 1, but instead of aminoguanidine nitrate, aminoguanidine sulfate is combined with nitric acid. In addition, the acid used in the method of Example 1 is used as the nitric acid component to provide a mode 4 of the present invention. Accordingly, the nitric acid can be recycled after the fuel of the present invention is recovered to improve the yield of the final product. The nitric acid used in a reaction can be used in a subsequent reaction regardless of which aminoguanidine salt was used in the initial reaction or in the subsequent reaction. Figure 4 provides an additional DSC graph of the AZODN of Example 1. As can be seen from this figure, the exothermic onset occurs at approximately 160 ° C with a decomposition greater than 185.1 ° C. Figure 5 shows a DSC graph of the fuel produced by example 13 (mode 2) with an exothermic start which is presented at 157.69 ° C and a decomposition greater than 184.98 ° C. Accordingly, the fuel of example 13 which uses aminoguanidine bicarbonate is substantially the same as the fuel of example 1, and therefore is azodiformamidine dinitrate. In the present invention, what is preferred is the use of aminoguanidine bicarbonate in the aminoguanidine salt. Figure 6 shows a DSC graph of the fuel produced by example 14 (mode 3) with an exothermic start which occurs at 150.39 ° C and a decomposition greater than 182.44 ° C. Accordingly, the fuel of example 14 which uses aminoguanidine sulfate is also substantially the same as the fuel of example 1, and therefore is azodiformamidine dinitrate. Figures 7, 8 and 9 * are IR spectra of the fuel of examples 1, 13 and 14 respectively. Figures 10 (a) - (d) are also IR spectra of the fuel of Examples 15, 1, 13 and 14, respectively. By comparing these spectra with the IR spectra of Figure 11, taken from Analytical Chemistry, Vol 23, p. 1594 (1951), it can be seen that the high oxygen balance fuel of the present invention utilizing aminoguanidine salt, including aminoguanidine nitrate, aminoguanidine bicarbonate and aminoguanidine sulfate, produces azodiformamidine dinitrate. The same is true with respect to the recycled acid of Example 15. In Table 11-14 are provided to demonstrate the use of representative AZODN made from aminoguanidine nitrate, aminoguanidine bicarbonate or aminoguanidine sulfate, or combinations thereof. As can be seen from the results in Table 11, the total ash production is low, the flame temperatures are acceptable and the risk tests are considered as "green", which means that they are acceptable. Specifically, Table 11 shows the properties of propellant AZODN shown by five (5) different formulations without the use of a binder.

R fa *. Ft > * & "", ^, eZ & amp & S & amp * -. V = á & i &ek Table 12 is an evaluation of the use of binders in the AZODN propellant compositions and particularly comparing the use of binder of QPAC-40 (polycarbonate) made by PAC Polymers, Inc. and CAB (cellulose-acetate-butyrate) prepared by Eastman Chemical, Inc. This table generally shows that an increase in the content of binders increases the initial crushing strength of the propellant composition of AZODN. Tables 13 and 14 demonstrate the effect of annealing time and fine particle size on an estimated strength and speed strength of various AZODN propellant compositions with or without a QPAC-40 binder.

TABLE 11 PROPELLERS AZODN W / O AGGLUTINANTS TABLE 12 EVALUATION OF THE AGGLUTINANTS IN ARCAIR-106 A PROPELLER OF AZODN COMPARISON OF OPAC-40 AND CAB TABLE 13 EFFECT OF RECYCLING TIME AND FINE PARTICLE SIZE ON RESISTANCE TO TEXTURING AND SPEED OF OUEMADE OF PROPELLERS ARCAIR-106 AZODN W AND W / O AGLUTINANT OPAC-40 £ ^^ "^^ Use to -40 KN 2 Anneal for 3 days @ 57.2 ° C (135 ° F) instead of overnight 3 n = 0.68 @ 13.8-27.6 MPa (2000-4000 psi), n = 1.0 @ 6.9- 13.8 MPa (1000-2000 psi) TABLE 14 COMPARISON OF PROPELLERS ARCAIR-106 B AZOND WITH AND W / O OPAC-40 TABLE 15 Table 15 shows the amount of insoluble and soluble decomposition product produced during a test ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ & amp; ^^ i s & ^ s ij- i? S? j ^ ^? ^^^^^^^^^^ i ^^^ of non-filtered inflator of the gas generating propellant composition of the present invention made from the reaction of nitric acid and aminoguanidine salt, such as aminoguanidine nitrate, aminoguanidine sulfate, or the preferred salt, aminoguanidine bicarbonate. Specifically, the test involved an inflator fires unit of physical test elements with a full-size PD-67 heavyweight without any filter collection system. The sample propellant was fired in a 60 liter tank and then rinsed to measure the amount of solid decomposition product in the tank. The pH of the resulting solid decomposition product was also obtained. As can be seen from the results set forth above in Table 15, the pH of the decomposition product is relatively neutral, which is important to avoid damage to the passengers of a car in which the propellant is used. the present invention during a collision in an air bag unide.d. In addition, the amount of insoluble unfiltered and soluble decomposition product is relatively low.

As can be seen from the previous examples and the corresponding tests, the fuel with a high oxygen balance of the present invention, preferably of azodiformamidine nitrate, shows attractive propellant attributes and could be useful in many pyrotechnic gas generating environments. .

Claims (25)

1. A pyrotechnic gas generating composition, characterized in that it comprises: a fuel with a high oxygen balance, wherein the fuel with a high oxygen balance in a solid yellow reaction product resulting from nitric acid and an aminoguanidine salt.

2. The pyrotechnic gas generating composition, according to claim 1, characterized in that the aminoguanidine salt is selected from the group consisting of aminoguanidine bicarbonate, aminoguanidine sulfate and mixtures thereof.

3. The pyrotechnic gas generating composition, according to claim 2, characterized in that the high oxygen balance fuel comprises 2-100% by weight of a pyrotechnic gas generating composition.

4. The pyrotechnic gas generating composition, according to claim 3, characterized in that the fuel with a high oxygen balance comprises 40-100% by weight of the pyrotechnic gas generating composition.

5. The pyrotechnic gas generating composition, according to claim 2, characterized in that the yellow reaction product resulting from the salt of aminoguanidine and nitric acid is prepared by a process comprising: (a) providing an aminoguanidine salt; (b) combining the salt of aminoguanidine with nitric acid to form a dispersion, wherein the dispersion proceeds through a color transition from a water white to straw color to a bright yellow color, the colcr being comparable to that of a solution of potassium dichromate.

6. The pyrotechnic gas generating composition according to claim 5, characterized in that 70% of the reactive grade nitric acid is combined with the aminoguanidine salt.

7. The pyrotechnic gas generating composition according to claim 2, characterized in that the yellow reaction product resulting from the salt of aminoguanidine and nitric acid is prepared by a process comprising: (a) combining the salt of aminoguanidine and water to form a suspension; (b) stirring 70% nitric acid in the suspension to form a dispersion; (c) heating the dispersion for a time in which the dispersion dissolves and proceeds with effervescence through a color transition from a water white to a straw color and a bright yellow color to form a solution, the bright yellow color is comparable with that of a potassium dichromate solution; (d) cooling the solution to precipitate the solid yellow reaction product.

8. The pyrotechnic gas generating composition, according to claim 7, characterized in that the dispersion is heated to 55-65 ° C and the solution is cooled to below 12 ° C.

9. The pyrotechnic gas generating composition, according to claim 2, characterized in that it comprises at least one oxidant, the oxidant comprises 0-98% by weight of the pyrotechnic gas generating composition.

10. The pyrotechnic gas generating composition according to claim 9, characterized in that at least one oxidant comprises 0-60% by weight of the pyrotechnic gas generating composition.

11. The pyrotechnic gas generating composition, according to claim 9, characterized in that at least one oxidant is substantially non-hygroscopic.

12. The pyrotechnic gas generating composition according to claim 9, characterized in that it includes at least one additive that is selected from the group consisting of a scavenger, ignition aid, ignition initiator, gas compression catalyst, ballistic modifier, slag formers, binders, energy binders, plasticizers, energy plasticizers, fuels, stabilizers, curing agents, curing catalysts, crosslinkers, inorganic coolants, organic coolants and auxiliary compounds and mixtures thereof.

13. The pyrotechnic gas generating composition, according to claim 9, characterized in that at least one oxidant is selected from the group consisting of nitrates, nitrites, chlorates, chlorites, perchlorates, chromates or mixtures thereof of a non-metallic material, alkali metal, alkaline earth metal, transition metal and transition metal complex.

14. The pyrotechnic gas generating composition, according to claim 13, characterized in that the oxidant comprises sodium citrate.

15. The pyrotechnic gas generating composition, according to claim 14, characterized in that the oxidant further comprises ammonium perchlorate.

16. The pyrotechnic gas generating composition according to claim 9, characterized in that the oxidant comprises a stabilized phase ammonium nitrate! ..

17. The pyrotechnic gas generating composition, according to claim 9, characterized in that the oxidant comprises ammonium perchlorate, the composition further comprises an additive which is selected from at least one of the group consisting of ammonium perchlorate, ammonium nitrate, potassium perchlorate, strontium nitrate, potassium nitrate, lithium nitrate, lithium carbonate and mixtures thereof.

18. The pyrotechnic gas generating composition, according to claim 2, characterized in that the reaction product is crystallized or recrystallized. ^ g? ^ jíaatój ^^^

19. The pyrotechnic gas generating composition according to claim 1, characterized in that it also comprises at least one other fuel with a high oxygen balance.

20. The pyrotechnic gas generating composition according to claim 19, characterized in that the other fuel with a high oxygen balance is selected from the group consisting of fuels derived from 10 hydrazodicarbonamidine, diazoguanidine, formamidine, bisformamidine, azobisformamidine and mixtures thereof.

21. The pyrotechnic gas generating composition, according to claim 20, characterized in that eL The azobisformamidine derivative is selected from the group consisting of guanyl azide nitrate, diazoguanidine nitrate, azobisnitroformamidine, 1,1'-diphenyl ether, and mixtures thereof.

22. A chemical supply system for fire suppression, characterized in that it comprises a container that includes: a fuel with a high oxygen balance, wherein the fuel with a high oxygen balance is a 25 reaction product resulting from a salt of aminoguanidiga ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ And nitric acid; and a chemical for the suppression of fire.

23. The chemical suppression system for fire suppression, according to claim 22, characterized in that the aminoguanidine salt is selected from the group consisting of aminoguanidine bicarbonate, aminoguanidine sulfate and mixtures thereof.

24. A method for inflating an article capable of retaining gas, characterized in that it comprises the steps of: igniting a gas generating composition comprising a fuel with a high oxygen balance, wherein the fuel with high oxygen balance is a yellow reaction product of a salt of aminoguanidine and nitric acid; generate gas and a solid material as reaction products of the reaction of the fuel with a high oxygen balance; passing the solid gaseous material through a filter, retaining at least a portion of the solid material in the filter, and allowing the gas to escape; to pass the filtered gas inside an article, so that the article is filled or inflated.

25. The method according to claim 24, characterized in that the aminoguanidine salt is selected from the group consisting of aminoguanidine bicarbonate, aminoguanidine sulfate and mixtures thereof. SUMMARY OF THE INVENTION A pyrotechnic gas generating composition is provided which includes a compound or fuel with a high oxygen balance, preferably dinitrate ds azodiformamidine, which is the reaction product resulting from a salt of aminoguanidine and nitric acid. Specifically, the compound or fuel with a high oxygen balance of the present invention is the reaction product resulting from aminoguanidine salts, such as aminoguanidine nitrate, aminoguanidine bicarbonate or aminoguanidine sulfate with nitric acid. Preferably, the aminoguanidine salt is aminoguanidine bicarbonate. The resulting reaction product is a yellow precipitate that can be used alone, with or without oxidants or other additives, for a very fast autodeflagration or in combination with additive oxidants. In each case, the gas generating composition provides both a high gas yield and a low production of solid combustion product. In addition, the precipitant is relatively non-nigroscopic and has a high burning rate. The gas generating composition is useful as a gas generator for an airbag of an occupant of a restraint system for a car, gun propellants, inflation and ejection devices, flotation devices, pyrotechnic equipment, suppression devices. of fire and propellant for rockets without smoke, with reduced smoke and with smoke.