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WO1998037040A1 - Gas generator propellant compositions - Google Patents

Gas generator propellant compositions Download PDF

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Publication number
WO1998037040A1
WO1998037040A1 PCT/US1998/002376 US9802376W WO9837040A1 WO 1998037040 A1 WO1998037040 A1 WO 1998037040A1 US 9802376 W US9802376 W US 9802376W WO 9837040 A1 WO9837040 A1 WO 9837040A1
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WO
WIPO (PCT)
Prior art keywords
gas generant
nitrate
metal
group
generant composition
Prior art date
Application number
PCT/US1998/002376
Other languages
French (fr)
Inventor
Norman H. Lundstrom
Original Assignee
Automotive Systems Laboratory, Inc.
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Filing date
Publication date
Application filed by Automotive Systems Laboratory, Inc. filed Critical Automotive Systems Laboratory, Inc.
Publication of WO1998037040A1 publication Critical patent/WO1998037040A1/en

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Classifications

    • CCHEMISTRY; METALLURGY
    • C06EXPLOSIVES; MATCHES
    • C06BEXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
    • C06B31/00Compositions containing an inorganic nitrogen-oxygen salt
    • CCHEMISTRY; METALLURGY
    • C06EXPLOSIVES; MATCHES
    • C06BEXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
    • C06B29/00Compositions containing an inorganic oxygen-halogen salt, e.g. chlorate, perchlorate
    • CCHEMISTRY; METALLURGY
    • C06EXPLOSIVES; MATCHES
    • C06BEXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
    • C06B43/00Compositions characterised by explosive or thermic constituents not provided for in groups C06B25/00 - C06B41/00
    • CCHEMISTRY; METALLURGY
    • C06EXPLOSIVES; MATCHES
    • C06DMEANS FOR GENERATING SMOKE OR MIST; GAS-ATTACK COMPOSITIONS; GENERATION OF GAS FOR BLASTING OR PROPULSION (CHEMICAL PART)
    • C06D5/00Generation of pressure gas, e.g. for blasting cartridges, starting cartridges, rockets
    • C06D5/06Generation of pressure gas, e.g. for blasting cartridges, starting cartridges, rockets by reaction of two or more solids

Definitions

  • the present invention relates to nontoxic gas generating compositions which upon combustion, rapidly generate gases that are useful -for inflating occupant safety restraints in motor vehicles and specifically, the invention relates to gas generants that produce combustion products having not only acceptable toxicity levels, but that also exhibit a relatively high gas volume to solid particulate ratio at acceptable flame temperatures.
  • pyrotechnic nonazide gas generants contain ingredients such as oxidizers to provide the required oxygen for rapid combustion and reduce the quantity of toxic gases generated, a catalyst to promote the conversion of toxic oxides of carbon and nitrogen to innocuous gases, and a slag forming constituent to cause the solid and liquid products formed during and immediately after combustion to agglomerate into filterable clinker-like particulates.
  • ingredients such as oxidizers to provide the required oxygen for rapid combustion and reduce the quantity of toxic gases generated, a catalyst to promote the conversion of toxic oxides of carbon and nitrogen to innocuous gases, and a slag forming constituent to cause the solid and liquid products formed during and immediately after combustion to agglomerate into filterable clinker-like particulates.
  • Other optional additives such as burning rate enhancers or ballistic modifiers and ignition aids, are used to control the ignitability and combustion properties of the gas generant .
  • nonazide gas generant compositions One of the disadvantages of known nonazide gas generant compositions is the amount and physical nature of the solid residues formed during combustion. The solids produced as a result of combustion must be filtered and otherwise kept away from contact with the occupants of the vehicle. It is therefore highly desirable to develop compositions that produce a minimum of solid particulates while still providing adequate quantities of a nontoxic gas to inflate the safety device at a high rate .
  • nonazide gas generants provide operable amounts of gas with a minimum of solid combustion products, in many cases, the mass of gas generant required compared to the mass of gas produced is still cause for concern.
  • the volume of the inflator necessarily reflects the gas generant required to produce the gas needed to deploy the inflator. A reduction in the volume of gas generant needed would result in a desirable reduction in inflator volume thereby enhancing design flexibility.
  • compositions have been designed to reduce the volume of the gas generant charge and the inflator.
  • copending PCT Application No. PCT/US95/00029 discloses metal complexes used as gas generants. These complexes comprise a cationic metal template, an oxidizing anion to balance the charge of the complex, and a neutral ligand containing hydrogen and nitrogen.
  • the complexes are desirable because they rapidly combust or decompose producing water and gases comprised only of hydrogen, oxygen, and/or nitrogen, and furthermore, occupy a relatively smaller volume when compared to known gas generant compositions.
  • the neat metallic complexes are friction and impact sensitive, and- therefore complicate safe handling, processing, and transportation requirements.
  • U.S. Patent No. 2,220,891 describes the use of metal ammine complexes in combination with ammonium nitrate.
  • the metal ammine complexes increase the sensitiveness of the composition thereby providing high density compositions desirable in quarry blasting where it is important to secure the maximum blasting effect.
  • PCT Application No. US95/00029, WO 95/19944 describes the addition of noncarbon-containing metallic fuels and oxidizers to metal ammine complexes. The application teaches away from the production of any gases containing anything other than nitrogen, oxygen, or hydrogen.
  • the metal ammine complexes, utilized as gas generant compounds for occupant restraint airbags, are sensitive to friction and impact.
  • a gas generant for a vehicle passenger restraint system employing at least one metal ammine or metal hydrazine complex, and, at least one high nitrogen fuel.
  • the metal complex comprises a neutral nitrogen- and hydrogen containing ligand coordinated to a metal cation, and, at least one nitrate, perchlorate, nitrite, chlorate, oxalate, halide, sulfate, peroxide, oxide, or other oxidizing anion to balance the complex charge.
  • a diluent such as a nonazide fuel results in a high density and less sensitive gas generant, and relatively speaking, produces abundant amounts of water vapor and gas such as carbon dioxide, nitrogen, and oxygen when compared to prior art gas generants.
  • one or more oxidizer compounds and/or a coolant may be added to the composition to further desensitize the complex.
  • gas generants of this invention are prepared by wet, aqueous or nonaqueous, and/or wet/dry blending and compaction of the comminuted ingredients.
  • the preferred gas generant compositions comprise, in particular, at least one metal coordination complex having ammine or hydrazine ligands, a metal cationic coordinating template, and a nitrate, nitrito, nitro, perchlorate, chlorate, chlorite, chromate, oxalate, halide, sulfate, peroxide, or oxide based anion to balance the charge of the complex, wherein the complex is combined with at least one high-nitrogen low impact sensitivity fuel and if desired, one or more additional oxidizers.
  • the central metal template of the complex is selected from alkaline earth and transitional metals.
  • the metal complex generally functions as a fuel/oxidizer and comprises 30-98% by weight of the total gas generant composition.
  • examples of metal ammine complexes include, but are not limited to, hexammine cobalt (III) nitrate, Co (NH 3 ) 6 (N0 3 ) 3 ; trinitrotriamminecobalt (III), Co (NH 3 ) 3 (N0 2 ) 3 ; hexammine cobalt (III) perchlorate, Co (NH 3 ) 6 (C10 4 ) 3 ; hexammine nickel (II) nitrate, [Ni (NH 3 ) 6 (N0 3 ) 2 ; and tetramminecopper (II) nitrate, Cu(NH 3 ) 4 (N0 3 ) _ .
  • Metal hydrazine complexes include, but are not limited to, tris-hydrazine zinc nitrate, Zn (N 2 H 4 ) 3 (N0 3 ) 2 ; bis-hydrazine magnesium perchlorate, Mg(N 2 H 4 ) 2 (C10 4 ) 2 ; bis-hydrazine magnesium nitrate, Mg(N 2 H 4 ) 2 (N0 3 ) 2 ; and bis-hydrazine platinum (II) nitrite, Pt (N0 2 ) 2 (NH 2 NH 2 ) 2 .
  • Nonazide fuels are preferably incorporated, however, high nitrogen azide or metal azido complex fuels, such as sodium azide, potassium azide, lithium azide, and azido pentammine cobalt (III) nitrate, may also be utilized.
  • Nonazide fuels are selected from a group comprising azoles, tetrazoles, triazoles, and triazines; nonmetal and metal derivatives of tetrazoles, triazoles, and triazines; cyclic nitramines, linear nitramines, and caged nitramines; derivatives of guanidine, hydrazine, hydroxylamine, and ammonia; and mixtures thereof.
  • guanidine derivative fuels include, but are not limited to, guanidine nitrate, aminoguanidine nitrate, diaminoguanidine nitrate, triaminoguanidine nitrate (wetted or unwetted) , guanidine perchlorate (wetted or unwetted) , triaminoguanidine perchlorate (wetted or unwetted) , guanidine picrate, triaminoguanidine picrate, cyanoguanidine, nitroguanidine (wetted or unwetted) , and nitroaminoguanidine (wetted or unwetted) .
  • high nitrogen nonazides employed as fuels in the gas generant compositions of this invention include 2 , 4 , 6-trihydrazino-s-triazine
  • guanidine compounds such as the metal and nonmetal salts of nitroaminoguanidine, metal and nonmetal salts of nitroguanidine, metal and nonmetal derivatives or salts of cyanoguanidine; nitroguanidine nitrate, and nitroguanidine perchlorate; azoles and tetrazoles such as urazole, aminourazole, lH-tetrazole, 5-aminotetrazole, 5- nitrotetrazole, 5-nitroaminotetrazole, 5, 5 ' -bitetrazole, diguanidinium-5, 5 ' -azotetrazolate, and diammonium 5,5'- bitetrazole; triazoles such as nitrotriazole, nitroaminotriazole, 3-nitro-l, 2 , 4-triazole-5-one; tria
  • An optional oxidizer compound is selected from a group comprising alkali metal, alkaline earth metal, and nonmetallic nitrates, nitrites, perchlorates, chlorates, chlorites, chromates, oxalates, halides, sulfates, sulfides, persulfates, peroxides, and oxides; cyclic nitramines, linear nitramines, and caged nitramines of normal or fine particle size; and combinations thereof.
  • the oxidizer generally comprises 0-50% by weight of the total gas generant composition.
  • compositions of the present invention may also include some of the additives heretofore used with gas generant compositions such as slag formers, compounding aids, ignition aids, ballistic modifiers, coolants, and NOX and CO scavenging agents.
  • Ballistic modifiers influence the temperature sensitivity and rate at which the gas generant or propellant burns.
  • the ballistic modifier (s) is selected from a group comprising alkali metal, alkaline earth metal, transitional metal, organometallic, and/or ammonium, guanidine, and triaminoguanidine salts of cyanoguanidine; alkali, alkaline earth, and transition metal oxides, sulfides, halides, chelates, metallocenes, ferrocenes, chromates, dichromates, trichromates, and chromites; and/or alkali metal, alkaline earth metal, guanidine, and triaminoguanidine borohydride salts; elemental sulfur; antimony trisulfide; and/or transition metal salts of acetylacetone; either separately or in combinations thereof.
  • Ballistic modifiers are employed in concentrations from about 0 to 25% by weight of the total gas generant composition, and utilize metals selected from groups 1-14 (new IUPAC) of the periodic table.
  • a catalyst aids in reducing the formation of toxic carbon monoxide, nitrogen oxides, and other toxic species.
  • a catalyst may be selected from a group comprising triazolates and/or tetrazolates; alkali, alkaline earth, and transition metal salts of tetrazoles, bitetrazoles, and triazoles; transition metal oxides; guanidine nitrate; nitroguanidine; and mixtures thereof.
  • a catalyst is employed in concentrations of 0 to 20% by weight of the total gas generant composition.
  • Suitable slag formers and coolants include lime, borosilicates, vycor glasses, bentonite clay, silica, alumina, silicates, aluminates, transition metal oxides, and mixtures thereof.
  • a slag former is employed in concentrations of 0 to 10% by weight of the total gas generant composition.
  • An ignition aid controls the temperature of ignition, and is selected from the group comprising finely divided elemental sulfur, boron, carbon black, and/or magnesium, aluminum, titanium, zirconium, or hafnium metal powders, and/or transition metal hydrides, and/or transition metal sulfides, and the hydrazine salt of 3-nitro-l, 2, 4-triazole-5- one, in combination or separately.
  • An ignition aid is employed in concentrations of 0 to 20% by weight of the total gas generant composition. Processing aids are utilized to facilitate the compounding of homogeneous mixtures.
  • Suitable processing aids include alkali, alkaline earth, and transition metal stearates; aqueous and/or nonaqueous solvents; molybdenum disulfide; graphite; boron nitride; polyethylene glycols; polypropylene carbonates; polyacetals; polyvinyl acetate; luoropolymer waxes commercially available under the trade name "Teflon” or "Viton", and silicone waxes.
  • the processing aid is employed in concentrations of 0 to 15% by weight of the total gas generant composition.
  • the various components described hereinabove for use with the metal ammine complexes of the present invention have been used in other known nonazide gas generant compositions.
  • references involving nonazide gas generant compositions describing various additives useful in the present invention include U.S. Patents No. 5,035,757; 5,084,118; 5,139,588; 4,948,439; 4,909,549; and 4,370,181, the teachings of which are herein incorporated by reference.
  • an oxidizer containing an alkaline earth metal, such as strontium may also function as a slag former, a ballistic modifier ignition aid, and a processing aid.
  • the materials may be aqueous or nonaqueous wet blended, or dry blended and attrited in a ball mill or Red Devil type paint shaker and then pelletized by compression molding.
  • the materials may also be ground separately or together in a fluid energy mill, sweco vibroenergy mill or bantam micropulverizer and then blended or further blended in a v- blender prior to compaction.
  • Multimodal particle size distribution will provide an optimum fit to ensure that the interstitial voids are filled, thereby resulting in a high density complex.
  • Compositions having components more sensitive to friction, impact, and electrostatic discharge should be wet ground separately followed by drying.
  • the resulting fine powder of each of the components may then be wet blended by tumbling with ceramic cylinders in a ball mill jar, for example, and then dried. Less sensitive components may be dry ground and dry blended at the same time.
  • the ratio of oxidizer to fuel is adjusted such that the oxygen balance is between -10.0% and +10.0% 0 2 by weight of composition as described above. More preferably, the ratio of oxidizer to fuel is adjusted such that the composition oxygen balance is between -4.0% and 1.0% 0 2 by weight of composition. Most preferably, the ratio of oxidizer to fuel is adjusted such that the composition oxygen balance is between -2.0% and 0.0% 0 2 by weight of composition.
  • the oxygen balance is the weight percent of 0 2 in the composition which is needed or liberated to form the stoichiometrically balanced products. Therefore, a negative oxygen balance represents an oxygen deficient composition whereas a positive oxygen balance represents an oxygen rich composition. It can be appreciated that the relative amounts of oxidizer and fuel will depend on the nature of the selected complex.
  • gas generant compositions of the present invention incorporate diluents that desensitize the metal ammine complexes due to a variety of physical and/or chemical parameters, such as chemical structure, hydration or water of crystallization, stoichiometry, particle size, packing, and coating.
  • the use of a substantially insensitive nonazide fuel with a metal ammine complex results in a high density, volumetrically efficient composition.
  • the monomodal particle size of the ammine complex allows formation of interstitial voids that are left vacant in a neat metal ammine complex.
  • the vacancies contribute to increased sensitivity.
  • the voids are filled with a negligible increase in volume. Filling the voids increases the density of the complex and provides more gas per gram of gas generant. As such, the gas generating properties are significantly enhanced without a corresponding increase in gas generant volume, or in solids formation upon combustion.
  • nonazide fuels decreases the sensitivity of the ammine complexes once the interstitial voids are occupied.
  • the optional oxidizers and coolants desensitize the ammine complexes in the same manner.
  • known metal ammine complex formulations as taught in WO 95/19944, utilize conventional inorganic metal fuels such as boron, magnesium, aluminum, silicon, titanium, and zirconium, and preclude the formation of gaseous carbon species upon combustion. Not only do certain of these fuels significantly increase the gas generant volume, they also result in more solids and less gas produced upon combustion. In addition, the sensitivity of the metal ammine complexes is not reduced.
  • compositions of the present invention are generally envisioned for use in conventional pyrotechnic gas inflators, for example, those referred to in U.S. Patent No, 4,369,079, incorporated herein by reference.
  • the methods of the prior art involve the use of a hermetically sealed metallic cartridge containing fuel, oxidizer, slag former, initiator and other selected additives.
  • the gas generants may also be tailored for use in hybrid inflators utilizing pressurized gases.
  • Hybrid inflator technology is based on heating a stored inert gas such as argon or helium to a desired temperature by burning a small amount of propellant.
  • Hybrid inflators that inherently operate at a lower temperature do not require cooling filters that must be used with pyrotechnic inflators to cool combustion gases.
  • the present invention is illustrated by the following examples wherein the components are quantified in weight percent of the total composition unless otherwise stated. Examples 1, 2, and 3 reflect scientific analysis based on the Naval Weapons Center Thermochemical Propellant Evaluation Program at a chamber pressure of 1000 psi and exhausting at atmospheric pressure. Values of the products in Examples 4 and 5 are obtained based on the given compositions and reactions .
  • a mixture of [Co(NH 3 ) 6 ] (N0 3 ) 3 , CH 6 N 4 0 3 , and Na(N0 3 ) is prepared as follows.
  • the components are separately ground to a fine powder by wet tumbling with ceramic cylinders in a ball mill jar.
  • the powder is then separated from the grinding cylinders, dried, and granulated to improve the flow characteristics of the material.
  • the ground components are blended in a v-blender prior to compaction. If desired, the homogeneously blended granules may then be cautiously compression molded into pellets by methods known to those skilled in the art.
  • the table below shows the chamber and exhaust flame temperatures in degrees Kelvin, the composition and quantity (in moles) of the significant chamber and exhaust compounds generated upon combustion, and the total quantity of chamber and exhaust gas in moles, generated from 100 g of the fuel composition.
  • Strontium and potassium salts also applicable in combination with sodium nitrate or separately.
  • Example 2 Hexamminecobalt III Nitrate/Guanidine Nitrate/ Sodium Nitrate/Strontium Nitrate
  • Sr(N0 3 ) 2 is prepared as in Example 1.
  • the components and percentages of the compositions of this example, as well as its combustion products and properties, are set forth in the table given in Example 1.
  • Example 3 Hexamminecobalt III Nitrate/5-Aminotetrazole/ Sodium Nitrate: [Co(NH 3 ) 6 ] (N0 3 ) 3 + CH 3 N 5 + 2 Na(N0 3 ) * ⁇ CoO + Na 2 0 + 10.5 H 2 0 + C0 2 + 8 N 2 + 1/4 0 2
  • Example 1 A mixture of [Co(NH 3 ) 6 ] (N0 3 ) 3 , CH 3 N 5 , and Na(N0 3 ) is prepared as in Example 1.
  • the components and percentages of the compositions of this example, as well as its combustion products and properties, are set forth in the table given in Example 1.
  • Example 4 Trinitrotriamminecobalt (III) /5 -aminotetrazole 7 [Co(NH 3 ) 3 (N0 2 ) 3 ] + CH 3 N 5 - 7 CoO + 33 H 2 0 + C0 2 + 47/2 N 2
  • a mixture of 95.33% [Co (NH 3 ) 3 (N0 2 ) 3 ] and 4.67% CH 3 N 5 is prepared as in Example 1.
  • the end products include 28.83% CoO (s) , 32.62% H 2 0 (v) , 2.42% C0 2 (g) , and 36.13% N 2 (g) .
  • the total weight percent of gaseous and vapor products is 71.17%.
  • the total gaseous and vapor moles/lOOg of gas generant is 3.157.
  • Example 5 Trinitrotriamminecobalt (III) /Guanidine Nitrate 4 [Co(NH 3 ) 3 (N0 2 ) 3 ] + CH 6 N 4 0 3 ⁇ 4 CoO + 21 H 2 0 + C0 2 + 14 N 2
  • a mixture of 89.05% [Co (NH 3 ) 3 (N0 2 ) 3 ] and 10.95% CH 6 N 4 0 3 is prepared as in Example 1.
  • the end products include 26.93% CoO (s) , 33.93% H 2 0 (v) , 3.95% C0 2 (g) , and 35.19% N 2 (g) .
  • the total weight percent of gaseous and vapor products is 73.07%.
  • the total gaseous and vapor moles/lOOg of gas generant is 3.232.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Combustion & Propulsion (AREA)
  • Air Bags (AREA)
  • Feeding, Discharge, Calcimining, Fusing, And Gas-Generation Devices (AREA)

Abstract

High nitrogen gas generant compositions, useful in inflating passenger restraint gas inflator bags, comprise at least one metal ammine or metal hydrazine coordination complex in combination with at least one low impact and low friction sensitivity high nitrogen fuel. The combination results in gas generants that are relatively more stable and less sensitive, and generate relatively more gas and less solids than known gas generant compositions.

Description

GAS GENERATOR PROPELLANT COMPOSITIONS
BACKGROUND OF THE INVENTION The present invention relates to nontoxic gas generating compositions which upon combustion, rapidly generate gases that are useful -for inflating occupant safety restraints in motor vehicles and specifically, the invention relates to gas generants that produce combustion products having not only acceptable toxicity levels, but that also exhibit a relatively high gas volume to solid particulate ratio at acceptable flame temperatures.
The evolution from azide-based gas generants to nonazide gas generants is well-documented in the prior art. The advantages of nonazide gas generant compositions in comparison with azide gas generants have been extensively described in the patent literature, for example, U.S. Patents No. 4,370,181; 4,909,549; 4,948,439; 5,084,118; 5,139,588 and 5,035,757, the discussions of which are hereby incorporated by reference.
In addition to a fuel constituent, pyrotechnic nonazide gas generants contain ingredients such as oxidizers to provide the required oxygen for rapid combustion and reduce the quantity of toxic gases generated, a catalyst to promote the conversion of toxic oxides of carbon and nitrogen to innocuous gases, and a slag forming constituent to cause the solid and liquid products formed during and immediately after combustion to agglomerate into filterable clinker-like particulates. Other optional additives, such as burning rate enhancers or ballistic modifiers and ignition aids, are used to control the ignitability and combustion properties of the gas generant .
One of the disadvantages of known nonazide gas generant compositions is the amount and physical nature of the solid residues formed during combustion. The solids produced as a result of combustion must be filtered and otherwise kept away from contact with the occupants of the vehicle. It is therefore highly desirable to develop compositions that produce a minimum of solid particulates while still providing adequate quantities of a nontoxic gas to inflate the safety device at a high rate .
While known nonazide gas generants provide operable amounts of gas with a minimum of solid combustion products, in many cases, the mass of gas generant required compared to the mass of gas produced is still cause for concern. The volume of the inflator necessarily reflects the gas generant required to produce the gas needed to deploy the inflator. A reduction in the volume of gas generant needed would result in a desirable reduction in inflator volume thereby enhancing design flexibility.
Several compositions have been designed to reduce the volume of the gas generant charge and the inflator. For example, copending PCT Application No. PCT/US95/00029 discloses metal complexes used as gas generants. These complexes comprise a cationic metal template, an oxidizing anion to balance the charge of the complex, and a neutral ligand containing hydrogen and nitrogen. The complexes are desirable because they rapidly combust or decompose producing water and gases comprised only of hydrogen, oxygen, and/or nitrogen, and furthermore, occupy a relatively smaller volume when compared to known gas generant compositions. However, the neat metallic complexes are friction and impact sensitive, and- therefore complicate safe handling, processing, and transportation requirements.
Description of the Prior Art U.S. Patent No. 544,582 describes the use of metal ammine complexes and ammonium nitrate. Metal ammine complexes in combination with ammonium nitrate are used to increase the sensitivity and explosiveness of the ammonium nitrate when packed in high densities .
U.S. Patent No. 2,220,891 describes the use of metal ammine complexes in combination with ammonium nitrate. The metal ammine complexes increase the sensitiveness of the composition thereby providing high density compositions desirable in quarry blasting where it is important to secure the maximum blasting effect. PCT Application No. US95/00029, WO 95/19944, describes the addition of noncarbon-containing metallic fuels and oxidizers to metal ammine complexes. The application teaches away from the production of any gases containing anything other than nitrogen, oxygen, or hydrogen. The metal ammine complexes, utilized as gas generant compounds for occupant restraint airbags, are sensitive to friction and impact.
SUMMARY OF THE INVENTION The aforementioned problems are solved by a gas generant for a vehicle passenger restraint system employing at least one metal ammine or metal hydrazine complex, and, at least one high nitrogen fuel. The metal complex comprises a neutral nitrogen- and hydrogen containing ligand coordinated to a metal cation, and, at least one nitrate, perchlorate, nitrite, chlorate, oxalate, halide, sulfate, peroxide, oxide, or other oxidizing anion to balance the complex charge. Combining the metallic complex with a diluent such as a nonazide fuel results in a high density and less sensitive gas generant, and relatively speaking, produces abundant amounts of water vapor and gas such as carbon dioxide, nitrogen, and oxygen when compared to prior art gas generants. If desired, one or more oxidizer compounds and/or a coolant may be added to the composition to further desensitize the complex.
The gas generants of this invention, preferably nonazide, are prepared by wet, aqueous or nonaqueous, and/or wet/dry blending and compaction of the comminuted ingredients.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In accordance with the present invention, the preferred gas generant compositions comprise, in particular, at least one metal coordination complex having ammine or hydrazine ligands, a metal cationic coordinating template, and a nitrate, nitrito, nitro, perchlorate, chlorate, chlorite, chromate, oxalate, halide, sulfate, peroxide, or oxide based anion to balance the charge of the complex, wherein the complex is combined with at least one high-nitrogen low impact sensitivity fuel and if desired, one or more additional oxidizers. When choosing an anion, nitrate based anions are preferred, however, other oxygenated ions may also be used as described above. The central metal template of the complex is selected from alkaline earth and transitional metals. The metal complex generally functions as a fuel/oxidizer and comprises 30-98% by weight of the total gas generant composition.
In accordance with the present invention, examples of metal ammine complexes include, but are not limited to, hexammine cobalt (III) nitrate, Co (NH3) 6 (N03) 3; trinitrotriamminecobalt (III), Co (NH3) 3 (N02) 3; hexammine cobalt (III) perchlorate, Co (NH3) 6 (C104) 3; hexammine nickel (II) nitrate, [Ni (NH3) 6 (N03) 2; and tetramminecopper (II) nitrate, Cu(NH3)4 (N03) _ . Metal hydrazine complexes include, but are not limited to, tris-hydrazine zinc nitrate, Zn (N2H4) 3 (N03) 2; bis-hydrazine magnesium perchlorate, Mg(N2H4) 2 (C104) 2; bis-hydrazine magnesium nitrate, Mg(N2H4)2 (N03)2; and bis-hydrazine platinum (II) nitrite, Pt (N02)2(NH2NH2)2.
Nonazide fuels are preferably incorporated, however, high nitrogen azide or metal azido complex fuels, such as sodium azide, potassium azide, lithium azide, and azido pentammine cobalt (III) nitrate, may also be utilized. Nonazide fuels are selected from a group comprising azoles, tetrazoles, triazoles, and triazines; nonmetal and metal derivatives of tetrazoles, triazoles, and triazines; cyclic nitramines, linear nitramines, and caged nitramines; derivatives of guanidine, hydrazine, hydroxylamine, and ammonia; and mixtures thereof. Examples of guanidine derivative fuels, either separately or in combination, include, but are not limited to, guanidine nitrate, aminoguanidine nitrate, diaminoguanidine nitrate, triaminoguanidine nitrate (wetted or unwetted) , guanidine perchlorate (wetted or unwetted) , triaminoguanidine perchlorate (wetted or unwetted) , guanidine picrate, triaminoguanidine picrate, cyanoguanidine, nitroguanidine (wetted or unwetted) , and nitroaminoguanidine (wetted or unwetted) .
Other high nitrogen nonazides employed as fuels in the gas generant compositions of this invention, either separately or in combination with the above described guanidine compounds, include 2 , 4 , 6-trihydrazino-s-triazine
(cyanuric hydrazide) ; 2 , 4 , 6-triamino-s-triazine (melamine) ; other guanidine compounds such as the metal and nonmetal salts of nitroaminoguanidine, metal and nonmetal salts of nitroguanidine, metal and nonmetal derivatives or salts of cyanoguanidine; nitroguanidine nitrate, and nitroguanidine perchlorate; azoles and tetrazoles such as urazole, aminourazole, lH-tetrazole, 5-aminotetrazole, 5- nitrotetrazole, 5-nitroaminotetrazole, 5, 5 ' -bitetrazole, diguanidinium-5, 5 ' -azotetrazolate, and diammonium 5,5'- bitetrazole; triazoles such as nitrotriazole, nitroaminotriazole, 3-nitro-l, 2 , 4-triazole-5-one; triazines such as melamine nitrate; and metallic and nonmetallic salts of the foregoing azoles, tetrazoles, triazoles, and triazines including manganese 5 , 5 ' -bitetrazole . The high nitrogen fuel generally comprises 0.1-70% by weight of the total gas generant composition.
An optional oxidizer compound is selected from a group comprising alkali metal, alkaline earth metal, and nonmetallic nitrates, nitrites, perchlorates, chlorates, chlorites, chromates, oxalates, halides, sulfates, sulfides, persulfates, peroxides, and oxides; cyclic nitramines, linear nitramines, and caged nitramines of normal or fine particle size; and combinations thereof. These include, for example, phase stabilized ammonium nitrate, ammonium nitrate, ammonium perchlorate, sodium nitrate, potassium nitrate, strontium nitrate, copper oxide, molybdenum disulfide, nitroguanidine, ammonium dinitramide, cyclotrimethylene trinitramine (RDX) , and cyclotetramethylene tetranitramine (HMX) . The oxidizer generally comprises 0-50% by weight of the total gas generant composition. From a practical standpoint, the compositions of the present invention may also include some of the additives heretofore used with gas generant compositions such as slag formers, compounding aids, ignition aids, ballistic modifiers, coolants, and NOX and CO scavenging agents. Ballistic modifiers influence the temperature sensitivity and rate at which the gas generant or propellant burns. The ballistic modifier (s) is selected from a group comprising alkali metal, alkaline earth metal, transitional metal, organometallic, and/or ammonium, guanidine, and triaminoguanidine salts of cyanoguanidine; alkali, alkaline earth, and transition metal oxides, sulfides, halides, chelates, metallocenes, ferrocenes, chromates, dichromates, trichromates, and chromites; and/or alkali metal, alkaline earth metal, guanidine, and triaminoguanidine borohydride salts; elemental sulfur; antimony trisulfide; and/or transition metal salts of acetylacetone; either separately or in combinations thereof. Ballistic modifiers are employed in concentrations from about 0 to 25% by weight of the total gas generant composition, and utilize metals selected from groups 1-14 (new IUPAC) of the periodic table.
The addition of a catalyst aids in reducing the formation of toxic carbon monoxide, nitrogen oxides, and other toxic species. A catalyst may be selected from a group comprising triazolates and/or tetrazolates; alkali, alkaline earth, and transition metal salts of tetrazoles, bitetrazoles, and triazoles; transition metal oxides; guanidine nitrate; nitroguanidine; and mixtures thereof. A catalyst is employed in concentrations of 0 to 20% by weight of the total gas generant composition.
Even though a very low concentration of solid combustion products are formed when the pyrotechnic gas generant compositions of the present invention are ignited, the formation of solid klinkers or slags is desirable in order to prevent unwanted solid decomposition products from passing through or plugging up the filter screens of the inflator. Suitable slag formers and coolants include lime, borosilicates, vycor glasses, bentonite clay, silica, alumina, silicates, aluminates, transition metal oxides, and mixtures thereof. A slag former is employed in concentrations of 0 to 10% by weight of the total gas generant composition.
An ignition aid controls the temperature of ignition, and is selected from the group comprising finely divided elemental sulfur, boron, carbon black, and/or magnesium, aluminum, titanium, zirconium, or hafnium metal powders, and/or transition metal hydrides, and/or transition metal sulfides, and the hydrazine salt of 3-nitro-l, 2, 4-triazole-5- one, in combination or separately. An ignition aid is employed in concentrations of 0 to 20% by weight of the total gas generant composition. Processing aids are utilized to facilitate the compounding of homogeneous mixtures. Suitable processing aids include alkali, alkaline earth, and transition metal stearates; aqueous and/or nonaqueous solvents; molybdenum disulfide; graphite; boron nitride; polyethylene glycols; polypropylene carbonates; polyacetals; polyvinyl acetate; luoropolymer waxes commercially available under the trade name "Teflon" or "Viton", and silicone waxes. The processing aid is employed in concentrations of 0 to 15% by weight of the total gas generant composition. The various components described hereinabove for use with the metal ammine complexes of the present invention have been used in other known nonazide gas generant compositions.
References involving nonazide gas generant compositions describing various additives useful in the present invention include U.S. Patents No. 5,035,757; 5,084,118; 5,139,588; 4,948,439; 4,909,549; and 4,370,181, the teachings of which are herein incorporated by reference. As taught in that art 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. For example, an oxidizer containing an alkaline earth metal, such as strontium, may also function as a slag former, a ballistic modifier ignition aid, and a processing aid.
Preparation of the metal ammine and metal hydrazine complexes of the present invention are described in copending application WO 95/19944, PCT Application No. PCT/US95/00029, the teachings of which are herein incorporated by reference. Preparation techniques are also taught in Mellors' Comprehensive Treatise on Inorganic and Theoretical Chemistry, Vol. VIII, (1928), pages 470-529, and, in a later addendum of Vol. VIII, Supplement II, Part II, (1967), pages 86-94, both of which were published by Longmans, Green, and Company, the teachings of which are herein incorporated by reference.
The manner and order in which the components of the fuel composition of the present invention are combined and compounded is not critical so long as a uniform mixture is obtained and the compounding is carried out under conditions which do not create unduly hazardous conditions or cause decomposition of the components employed. For example, the materials may be aqueous or nonaqueous wet blended, or dry blended and attrited in a ball mill or Red Devil type paint shaker and then pelletized by compression molding. The materials may also be ground separately or together in a fluid energy mill, sweco vibroenergy mill or bantam micropulverizer and then blended or further blended in a v- blender prior to compaction. Multimodal particle size distribution will provide an optimum fit to ensure that the interstitial voids are filled, thereby resulting in a high density complex. Compositions having components more sensitive to friction, impact, and electrostatic discharge should be wet ground separately followed by drying. The resulting fine powder of each of the components may then be wet blended by tumbling with ceramic cylinders in a ball mill jar, for example, and then dried. Less sensitive components may be dry ground and dry blended at the same time.
When formulating a composition, the ratio of oxidizer to fuel, wherein the oxidizer and fuel each comprise a portion of the metal complex, is adjusted such that the oxygen balance is between -10.0% and +10.0% 02 by weight of composition as described above. More preferably, the ratio of oxidizer to fuel is adjusted such that the composition oxygen balance is between -4.0% and 1.0% 02 by weight of composition. Most preferably, the ratio of oxidizer to fuel is adjusted such that the composition oxygen balance is between -2.0% and 0.0% 02 by weight of composition. The oxygen balance is the weight percent of 02 in the composition which is needed or liberated to form the stoichiometrically balanced products. Therefore, a negative oxygen balance represents an oxygen deficient composition whereas a positive oxygen balance represents an oxygen rich composition. It can be appreciated that the relative amounts of oxidizer and fuel will depend on the nature of the selected complex.
The gas generant compositions of the present invention incorporate diluents that desensitize the metal ammine complexes due to a variety of physical and/or chemical parameters, such as chemical structure, hydration or water of crystallization, stoichiometry, particle size, packing, and coating.
For example, the use of a substantially insensitive nonazide fuel with a metal ammine complex results in a high density, volumetrically efficient composition. The monomodal particle size of the ammine complex allows formation of interstitial voids that are left vacant in a neat metal ammine complex. The vacancies contribute to increased sensitivity. By adding low sensitivity nonazide fuels, the voids are filled with a negligible increase in volume. Filling the voids increases the density of the complex and provides more gas per gram of gas generant. As such, the gas generating properties are significantly enhanced without a corresponding increase in gas generant volume, or in solids formation upon combustion. Furthermore, the less sensitive nature of the nonazide fuels decreases the sensitivity of the ammine complexes once the interstitial voids are occupied. The optional oxidizers and coolants desensitize the ammine complexes in the same manner. In contrast, known metal ammine complex formulations as taught in WO 95/19944, utilize conventional inorganic metal fuels such as boron, magnesium, aluminum, silicon, titanium, and zirconium, and preclude the formation of gaseous carbon species upon combustion. Not only do certain of these fuels significantly increase the gas generant volume, they also result in more solids and less gas produced upon combustion. In addition, the sensitivity of the metal ammine complexes is not reduced. Practically speaking, greater volumetric efficiency facilitates increased design flexibility depending on the quantities of gas desired. Due to greater gas and minimal solids production, reduced filtration needs result in correspondingly smaller filters and inflators. The compositions of the present invention are generally envisioned for use in conventional pyrotechnic gas inflators, for example, those referred to in U.S. 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 fuel, oxidizer, slag former, initiator and other selected additives. However, the gas generants may also be tailored for use in hybrid inflators utilizing pressurized gases. Hybrid inflator technology is based on heating a stored inert gas such as argon or helium to a desired temperature by burning a small amount of propellant. Hybrid inflators that inherently operate at a lower temperature do not require cooling filters that must be used with pyrotechnic inflators to cool combustion gases. The present invention is illustrated by the following examples wherein the components are quantified in weight percent of the total composition unless otherwise stated. Examples 1, 2, and 3 reflect scientific analysis based on the Naval Weapons Center Thermochemical Propellant Evaluation Program at a chamber pressure of 1000 psi and exhausting at atmospheric pressure. Values of the products in Examples 4 and 5 are obtained based on the given compositions and reactions .
Example 1: Hexamminecobalt III Nitrate/Guanidine Nitrate/
Sodium Nitrate [Co(NH3)6] (N03)3 + CH6N403 + 4/3 Na(N03)*
→ CoO + 2/3 Na20 + 12 H20 + C02 + 43/6 N2 + 1/6 02 A mixture of [Co(NH3)6] (N03)3, CH6N403, and Na(N03) is prepared as follows. The components are separately ground to a fine powder by wet tumbling with ceramic cylinders in a ball mill jar. The powder is then separated from the grinding cylinders, dried, and granulated to improve the flow characteristics of the material. Next, the ground components are blended in a v-blender prior to compaction. If desired, the homogeneously blended granules may then be cautiously compression molded into pellets by methods known to those skilled in the art. The table below shows the chamber and exhaust flame temperatures in degrees Kelvin, the composition and quantity (in moles) of the significant chamber and exhaust compounds generated upon combustion, and the total quantity of chamber and exhaust gas in moles, generated from 100 g of the fuel composition.
The components of the compositions of Examples 1-3 are set forth below.
Ex 1 Ex 2 Ex 3
Hexamminecobalt III nitrate 60.00 55.52 57.64
Guanidine nitrate 21.00 19.52
5-aminotetrazole 14.12
Sodium nitrate 19.00 13.6028.24
Strontium nitrate 11.36
Density, gms/c.c. 1.923 1.9912.063
Combustion Chamber Information (1000 psi)
M.W. of Comp. 26.43327.625
27.683 Total Gas, Moles/lOOg 3.471 3.3243.239
Flame temp . , °K 1907 1849 1990
Total Gas N2/02/C02/H20 % 77.95 75.3374.08
Nitrogen, moles 1.23231.1710
1.3259 Nitrogen, % 34.50 32.7937.13 Oxygen, moles .0198 .0920.0395 Oxygen , % .6336 2.9441.264 C02, moles 0.17180.1398
0.1657 C02 , % 7.559 6.1517.291
Water Vapor, moles 1.95881.8579
1.5760 Water Vapor, % 35.26 33.4428.39 N02, moles 6.19E-06 2.68E-05 1.53E-05
N02, % 285E-06 123E-05
70.5E-05 NO, moles 0.00240.0042
0.0045 NO, % .0721 .1264.1355
CO, moles 1.60E-04 3.41E-05
2.21E-04 CO, % 44.8E-04 95.0E-05
61.9E-04 CoO, moles 0.17280.1599
0.1660 CoO, % 12.96 11.9912.45 NaOH, moles .2220 .1190.3298 NaOH, % 8.902 4.76013.223 Na2C03, moles .0200 Na2C03 , % 2.120 SrO, moles .0535 SrO, % 5.544 Ex 1 Ex 2 Ex 3
Exhaust Information (14.70 psi)
M.W. of Comp. 27.24 29.1829.00 Total Gas, Moles/lOOg 3.386 3.2403.118
Flame temp., °K 1079 1055 1208
Total Gas N2/02/C02/H20 % 75.24 73.0769.86
Nitrogen, moles 1.234 1.1731.328
Nitrogen, % 34.55 32.8437.18 Oxygen, moles .0210 .0677.0418
Oxygen, % .6720 2.1661.337
C02, moles 0.06020.0799
0.0024
C02, % 2.737 3.516.1056 Water Vapor, moles 2.071 1.9191.741
Water Vapor, % 37.28 34.5431.34
N02, moles
N02, %
NO, moles 0.00003 0.00004 0.00013
NO, % .0009 .0012.0039
CO, moles
CO, %
CoO, moles 0.1728 0.1660 CoO, % 12.96 12.45
Co304 , moles . 0533
Co304 , % 12 . 84
NaOH, moles .000052.04E-05
.00503 NaOH, % .0020 81.6E-05 .2012
Na2C03, moles .1117 .0799.1635
Na2C03, % 11.84 8.4717.33
SrO, moles .0537
SrO, % 5.544
* Strontium and potassium salts also applicable in combination with sodium nitrate or separately.
Example 2: Hexamminecobalt III Nitrate/Guanidine Nitrate/ Sodium Nitrate/Strontium Nitrate
[Co(NH3)6] (N03)3 + CH6N403 + Na(N03)* + 1/3 Sr(N03)2
→ CoO + 1/2 Na20 + 12 H20 + 1/3 SrO + C02 + 22/3 N2 + 7/12 02
A mixture of [Co (NH3) 6] (N03) 3, CH6N403, Na(N03), and
Sr(N03)2 is prepared as in Example 1. The components and percentages of the compositions of this example, as well as its combustion products and properties, are set forth in the table given in Example 1.
* Potassium salt also applicable. Example 3: Hexamminecobalt III Nitrate/5-Aminotetrazole/ Sodium Nitrate: [Co(NH3)6] (N03)3 + CH3N5 + 2 Na(N03)* → CoO + Na20 + 10.5 H20 + C02 + 8 N2 + 1/4 02
A mixture of [Co(NH3)6] (N03)3, CH3N5, and Na(N03) is prepared as in Example 1. The components and percentages of the compositions of this example, as well as its combustion products and properties, are set forth in the table given in Example 1.
* Potassium and strontium salts also applicable.
Example 4: Trinitrotriamminecobalt (III) /5 -aminotetrazole 7 [Co(NH3)3(N02)3] + CH3N5 - 7 CoO + 33 H20 + C02 + 47/2 N2 A mixture of 95.33% [Co (NH3) 3 (N02) 3] and 4.67% CH3N5 is prepared as in Example 1. The end products include 28.83% CoO (s) , 32.62% H20 (v) , 2.42% C02 (g) , and 36.13% N2 (g) . The total weight percent of gaseous and vapor products is 71.17%. The total gaseous and vapor moles/lOOg of gas generant is 3.157.
Example 5: Trinitrotriamminecobalt (III) /Guanidine Nitrate 4 [Co(NH3)3(N02)3] + CH6N403 → 4 CoO + 21 H20 + C02 + 14 N2
A mixture of 89.05% [Co (NH3) 3 (N02) 3] and 10.95% CH6N403 is prepared as in Example 1. The end products include 26.93% CoO (s) , 33.93% H20 (v) , 3.95% C02 (g) , and 35.19% N2 (g) . The total weight percent of gaseous and vapor products is 73.07%. The total gaseous and vapor moles/lOOg of gas generant is 3.232.
While the foregoing examples illustrate the use of preferred fuels and oxidizers it is to be understood that the practice of the present invention is not limited to the particular fuels and oxidizers illustrated and similarly does not exclude the inclusion of other additives as described above and as defined by the following claims, or those readily apparent to one skilled in the art.

Claims

I CLAIM :
1. A gas generant composition useful for inflating an automotive air bag passive restraint system comprising: at least one metal coordination complex comprising a transition metal, a nitrogen and hydrogen containing ligand, and an anionic component to balance the charge of the complex; and at least one high nitrogen fuel selected from the group consisting of nonazide and azide fuels, with the proviso the gas generant composition does not contain the following: cobalt (III) triammine trinitrate, Co (NH3) 3 (N03) 3, or; copper (II) diammine dinitrate, Cu(NH3)2 (N03)2, and an oxide mixture of V205/Mo03.
2. The gas generant composition of Claim 1 wherein said metal coordination complex is employed in a concentration of 30 to 98% by weight of the gas generant composition and said at least one high nitrogen fuel is employed in a concentration of .1 to 70% by weight of the gas generant composition.
3. The gas generant composition of Claim 1 wherein said nonazide fuels are selected from a group consisting of urazoles, tetrazoles, triazoles, and triazines; derivatives of urazoles, tetrazoles, triazoles, and triazines; cyclic nitramines, linear nitramines, and caged nitramines; derivatives of guanidine, hydrazine, hydroxylamine , and ammonia .
4. The gas generant of Claim 3 wherein said guanidine derivative is selected from the group consisting of guanidine nitrate, aminoguanidine nitrate, diaminoguanidine nitrate, triaminoguanidine nitrate (wetted or unwetted) , guanidine perchlorate (wetted or unwetted) , triaminoguanidine perchlorate (wetted or unwetted) , guanidine picrate, triaminoguanidine picrate, cyanoguanidine, nitroguanidine (wetted or unwetted) , nitroaminoguanidine (wetted or unwetted) , metal and nonmetal salts of nitroaminoguanidine, metal and nonmetal derivatives and salts of cyanoguanidine; metal and nonmetal salts of nitroguanidine, nitroguanidine nitrate, nitroguanidine perchlorate, and mixtures thereof.
5. The gas generant of Claim 3 wherein said urazoles, tetrazoles, and derivatives thereof are selected from a group consisting of urazole, aminourazole, tetrazole, lH-tetrazole, 5 -aminotetrazole, 5-nitrotetrazole, 5-nitroaminotetrazole, 5,5' -bitetrazole, diguanidinium-5, 5 ' -azotetrazolate, diammonium 5, 5 ' -bitetrazole, manganese 5 , 5 ' -bitetrazole, metal and nonmetal salts of said azoles and tetrazoles, and mixtures thereof .
6. The gas generant of Claim 3 wherein said triazoles, triazines, and derivatives thereof, are selected from the group consisting of 2, 4, 6-trihydrazino-s-triazine, 2,4,6- triamino-s-triazine, melamine nitrate, triazole, nitrotriazole, nitroaminotriazole, 3-nitro-l, 2, 4-triazole-5- one, metallic and nonmetallic salts of said triazoles and triazines and mixtures thereof.
7. The gas generant composition of Claim 1 wherein said azide fuel(s) is selected from the group consisting of azide and metal azido complex fuels
8. The gas generant composition of Claim 1 further comprising at least one oxidizer compound selected from the group consisting of alkali metal, alkaline earth metal, and nonmetallic nitrates, nitrites, perchlorates, chlorates, chlorites, chromates, oxalates, halides, sulfates, persulfates, peroxides, and oxides; and mixtures thereof, wherein said oxidizer compound is employed in a concentration of .1-50% by weight of the total gas generant composition.
9. The gas generant of Claim 8 wherein said oxidizer compound is selected from the group consisting of phase stabilized ammonium nitrate, ammonium nitrate, ammonium perchlorate, sodium nitrate, potassium nitrate, strontium nitrate, copper oxide, molybdenum disulfide, nitroguanidine, ammonium dinitramide, cyclotrimethylene trinitramine, cyclotetramethylene tetranitramine, and mixtures thereof.
10. The gas generant of claim 1 further comprising a ballistic modifier selected from the group consisting of organometallic compounds; metal oxides, metal halides, metal sulfides, and metal chromium salts, the metal being selected from Groups 1-14 of the Periodic Table of Elements; elemental sulfur; alkali metal, alkaline earth metal, guanidine and triaminoguanidine borohydrides ; and mixtures thereof, employed in a concentration of 0.1 to 25% by weight of the total gas generant .
11. The gas generant of claim 1 further comprising an inert slag former and coolant selected from the group consisting of lime, borosilicates, vycor glasses, bentonite clay, silica, alumina, silicates, aluminates, transition metal oxides, -and mixtures thereof, employed in a concentration of 0.1 to 10% by weight of the total gas generant composition.
12. The gas generant of claim 1 further comprising a catalyst selected from the group consisting of alkali metal, alkaline earth metal and transition metal salts of bitetrazoles, and mixtures thereof, employed in a concentration of 0.1 to 20% by weight of the total gas generant
13. The gas generant composition of claim 1 further comprising an ignition aid selected from the class consisting of finely divided elemental sulfur, boron, carbon black, magnesium, aluminum, titanium, zirconium and hafnium, transition metal hydrides, transition metal sulfides and mixtures thereof, employed in a concentration of 0.1 to 20% by weight of the gas generant.
14. The gas generant composition of claim 1 further comprising a processing aid selected from the group consisting of molybdenum disulfide; graphite; boron nitride; alkali, alkaline- earth, and transition metal stearates; polyethylene glycols; polypropylene carbonates; lactose; polyacetals; polyvinyl acetates; polycarbonates; polyvinyls; alcohols; fluoropolymers ; paraffins; silicone waxes; and mixtures thereof, employed in a concentration of 0.1 to 15% by weight of the gas generant .
15. The gas generant composition of claim 1 wherein said metal coordination complex is selected from the group of metal ammine complexes consisting of hexammine cobalt (III) nitrate, trinitrotriamminecobalt (III) , hexammine cobalt
(III) perchlorate, hexammine nickel (II) nitrate, and tetramminecopper (II) nitrate.
16. The gas generant composition of claim 1 wherein said metal coordination complex is selected from the group of metal hydrazine complexes consisting of tris-hydrazine zinc nitrate, bis-hydrazine magnesium perchlorate, bis-hydrazine magnesium nitrate, and bis-hydrazine platinum (II) nitrite.
17. The gas generant composition of claim 1 wherein said ligand is selected from the group consisting of ammonia and hydrazine.
18. The gas generant composition of claim 1 wherein said anionic component is selected from the group consisting of nitrate, nitrite, perchlorate, chlorate, chlorite, chromate, oxalate, halide, sulfate, peroxide, or oxide based anions .
19. The gas generant composition of claim 1 comprising a mixture of trinitrotriamminecobalt (III) and 5- aminotetrazole .
20. The gas generant composition of claim 1 comprising a mixture of trinitrotriamminecobalt (III) and guanidine nitrate .
21. The gas generant composition of claim 8 comprising a mixture of hexamminecobalt (III) nitrate, guanidine nitrate, and sodium nitrate.
22. The gas generant composition of claim 8 comprising a mixture of hexamminecobalt (III) nitrate, guanidine nitrate, sodium nitrate, and strontium nitrate.
23. The gas generant composition of claim 8 comprising a mixture of hexamminecobalt III nitrate, 5-aminotetrazole, and sodium nitrate .
24. The gas generant composition of Claim 7 wherein said azide fuel(s) is selected from the group consisting of sodium azide, potassium azide, lithium azide, and azido pentammine cobalt (III) nitrate.
25. The gas generant of Claim 10 wherein said organometallic compounds are selected from the group consisting of metallocenes and chelates of metals.
PCT/US1998/002376 1997-02-10 1998-02-03 Gas generator propellant compositions WO1998037040A1 (en)

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