Classifications

• • C—CHEMISTRY; METALLURGY
  • C06—EXPLOSIVES; MATCHES
  • C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
  • C06B45/00—Compositions or products which are defined by structure or arrangement of component of product
  • C06B45/04—Compositions or products which are defined by structure or arrangement of component of product comprising solid particles dispersed in solid solution or matrix not used for explosives where the matrix consists essentially of nitrated carbohydrates or a low molecular organic explosive
  • C06B45/06—Compositions or products which are defined by structure or arrangement of component of product comprising solid particles dispersed in solid solution or matrix not used for explosives where the matrix consists essentially of nitrated carbohydrates or a low molecular organic explosive the solid solution or matrix containing an organic component
  • C06B45/10—Compositions or products which are defined by structure or arrangement of component of product comprising solid particles dispersed in solid solution or matrix not used for explosives where the matrix consists essentially of nitrated carbohydrates or a low molecular organic explosive the solid solution or matrix containing an organic component the organic component containing a resin
• • C—CHEMISTRY; METALLURGY
  • C06—EXPLOSIVES; MATCHES
  • C06D—MEANS FOR GENERATING SMOKE OR MIST; GAS-ATTACK COMPOSITIONS; GENERATION OF GAS FOR BLASTING OR PROPULSION (CHEMICAL PART)
  • C06D5/00—Generation of pressure gas, e.g. for blasting cartridges, starting cartridges, rockets
  • C06D5/06—Generation of pressure gas, e.g. for blasting cartridges, starting cartridges, rockets by reaction of two or more solids

Definitions

• This invention relates generally to materials for use in gas generation such as for forming an inflation gas such as for inflating inflatable devices such as airbag cushions included in automobile inflatable restraint systems and, more particularly, to extrudable, perchlorate-containing gas generant compositions which produce or result in gaseous effluents having reduced levels of various undesirable constituents and which are conducive or easily adaptable to manufacture or production by extrusion processing.
• Such airbag restraint systems normally include: one or more airbag cushions, housed in an uninflated and folded condition to minimize space requirements; one or more crash sensors mounted on or to the frame or body of the vehicle to detect sudden deceleration of the vehicle; an activation system electronically actuated by the crash sensors; and an inflator device that produces or supplies a gas to inflate the airbag cushion. Tn the event of a sudden deceleration of the vehicle, the crash sensors actuate the activation system which in turn actuates the inflator device which begins to inflate the airbag cushion in a matter of milliseconds.
• inflator devices which form or produce inflation gas via the combustion of a gas generating pyrotechnic material, e.g., a "gas generant," are well known.
• gas generant a gas generating pyrotechnic material
• inflator devices that use the high temperature combustion products, including additional gas products, generated by the burning of the gas generant to supplement stored and pressurized gas to inflate one or more airbag cushions are known, hi other known inflator devices, the combustion products generated by burning the gas generant may be the sole or substantially sole source for the inflation gas used to inflate the airbag cushion.
• such inflator devices include a filter to remove dust or particulate matter formed during the combustion of a gas generant composition from the inflation gas to limit or prevent occupant exposure to undesirable and/or toxic combustion byproducts.
• a vehicle may include a driver airbag, a passenger airbag, one or more seat. belt pretensioners, one or more knee bolsters, and/or one or more inflatable belts, each with an associated inflator device, to protect the driver and passengers from frontal crashes.
• the vehicle may also include one or more head/thorax cushions, thorax cushions, and/or curtains, each with at least one associated inflator device, to protect the driver and passengers from side impact crashes.
• the gaseous effluent or inflation gas produced by all of the inflator devices within a particular vehicle when taken as whole, are required to satisfy strict content limitations in order to meet current industry safety guidelines.
• the gas generant compositions used in such inflator devices produce aslittle as possible of undesirable effluents such as hydrogen chloride, carbon monoxide, nitrogen dioxide and nitric oxide.
• a number of gas generant compositions are known that include perchlorate additives such as, for example, ammonium perchlorate and/or alkali metal perchlorates as an oxidizer.
• perchlorate additives are typically employed in gas generant compositions as a source of oxygen which promotes efficient combustion of the gas generant composition, e.g., complete conversion of carbon to carbon dioxide, hydrogen to water, and nitrogen to nitrogen gas.
• Perchlorate additives commonly also produce hydrogen chloride as a gaseous byproduct of combustion which, in too large a concentration, may be toxic and/or corrosive.
• Hydrogen chloride can be removed from the combustion gas stream by including an alkali or alkaline earth metal salt in the gas generant composition.
• alkali or alkaline earth metal salts react with the hydrogen chloride to produce less or nontoxic alkali or alkaline earth metal chlorides such as, for sample, sodium or potassium chloride.
• alkali or alkaline earth metal chlorides undesirably form as fine particulate matter or dust which can escape the inflator device.
• perchlorate additives typically increases the combustion temperature of a pyrotechnic gas generant composition often resulting in increased levels of undesirable and potentially toxic effluent gases such as ammonia and carbon monoxide.
• One technique of controlling the composition of gaseous effluent generated via combustion of the gas generant composition involves manipulation of the equivalence ratio such as, for example, by varyingthe concentration of oxidizer in the gas generant composition.
• gas generant compositions are produced using a spray dry process.
• the gas generant compositions are typically prepared as a slurry of particulate materials in a carrier fluid such as, for. example, water or alcohol.
• a carrier fluid such as, for. example, water or alcohol.
• the slurried compositions are then sprayed as a fine mist such that the carrier fluid is simultaneously dried and a powder material is recovered.
• Thepowdermaterial is subsequently consolidated using high speed presses into gas generant bodies such as, for example, in the form of pellets, tablets, wafers and the like.
• gas generant compositions used in such inflator devices can be produced in an economical and/or efficient manner.
• One such process for more efficiently preparing solid gas generant bodies for use in an associate inflator device includes, for example, an extrusion process.
• extrusion processes are typically processes wherein a viscous or paste-like gas generant composition may be compounded and extruded into a desired shape.
• Individual gas generant bodies may be formed such as by cutting or otherwise portioning the gas generant composition as it is extruded.
• Such individual gas generant bodies may be cut into various desirable sizes such as, for example, in a size that permits multiple bodies to be placed within a combustion chamber of an inflator device or, alternatively, in a size that permits the placement of a single monolithic grain within the combustion chamber.
• extrusion processes can desirably be employed to reduce production costs such as by eliminating separate formation and consolidation steps and reducing equipment costs.
• gas generant materials for use in automotive inflatable restraint applications must be sufficiently reactive such that upon the proper initiation of the reaction thereof, the resulting gas producing or generating reaction occurs sufficiently rapidly such that an associated inflatable air bag cushion is properly inflated so as to provide desired impact protection to an associate vehicle occupant.
• Gas generant compositions which can be employed in extrusion processes commonly include a binder material that holds the components of the composition together and imparts rigidity and/or strength the extruded grain.
• binder materials can undesirably lower the burn rate of the gas generant composition which can have a deleterious effect on the rate at which inflation gas is produced and/or the quantity of inflation gas produced to inflate an associated airbag cushion.
• a general object of the invention is to provide an improved gas generant composition.
• a more specific objective of the invention is to overcome one or more of the problems described above.
• the general object of the invention can be attained, at least in part, through an extrudable gas generant composition including a non-azide, organic, nitrogen-containing fuel, at least one copper-containing compound, a perchlorate additive and a polymeric binder effective to render the gas generant composition extrudable.
• the at least one copper-containing compound is selected from basic copper nitrate, cupric oxide, a copper diammine dinitrate-arnrnoniurn nitrate mixture wherein ammonium nitrate is present in the mixture in a range of about 3 to about 90 weight percent, copper diammine bitetrazole, a copper-nitrate complex resulting from reaction of 5-aminotetrazole with basic copper nitrate, or combinations thereof.
• the perchlorate additive includes at least one perchlorate material selected from alkali metal perchlorates and ammonium perchlorate.
• the perchlorate additive is present in a relative amount effective to result in a gaseous effluent, when the gas generant composition is combusted, having a reduced content of at least one species selected from carbon monoxide, ammonia, nitrogen dioxide and nitric oxide, as compared to a same gas generant composition which is free of the perchlorate additive.
• the prior art generally fails to provide gas generant compositions that facilitate or otherwise permit the inclusion of one or more perchlorate additives while simultaneously inhibiting the formation or otherwise reducing the amounts or levels of undesirable effluents such as carbon monoxide, ammonia, nitrogen dioxide and nitric oxide.
• the prior art further generally fails to provide gas generant compositions containing one or more perchlorate additives that maybe extruded to form multiple individual gas generant bodies or a monolithic grain having a burn rate effective to reliably and rapidly produce a gaseous effluent to inflate an associated airbag cushion.
• the invention further comprehends an extrudable gas generant composition
• an extrudable gas generant composition comprising: a non-azide, organic, nitrogen-containing fuel present in a relative amount of 5 to 60 composition weight percent; a copper-containing compound selected from the group consisting of basic copper nitrate, cupric oxide, copper diammine dinitrate-ammonium nitrate mixture wherein ammonium nitrate is present in the mixture in a range of about 3 to about 90 weight percent, copper diammine bitetrazole, a copper-nitrate complex resulting from reaction of
• a perchlorate additive comprising at least one perchlorate material selected from the group consisting of alkali metal perchlorates and ammonium perchlorate, the perchlorate additive, present in a relative amount of 1 to about 10 composition weight, effective to result in a gaseous effluent, when the gas generant composition is combusted, having a reduced content of at least one species selected from the group consisting of carbon monoxide, ammonia, nitrogen dioxide and nitric oxide, as compared to a same gas generant composition free of the perchlorate additive; and a polymeric binder material present in a relative amount of 1 to 20 composition weight percent and effective to render the gas generant composition extrudable, the polymeric binder material selected from the group consistingof cellulosicmaterials, natural gums,polyacrylates, polyacrylamides, poly
• the invention still further comprehends an extrudable gas generant composition
• an extrudable gas generant composition comprising: 5 to 60 composition weight percent guanidine nitrate;
• a copper-containing compound selected from the group consisting of basic copper nitrate, cupric oxide, copper diammine dinitrate-ammonium nitrate mixture wherein ammonium nitrate is present in the mixture in a range of about 3 to about 90 weight percent, copper diammine bitetrazole, a copper-nitrate complex resulting from reaction of 5-aminotetrazole with basic copper , nitrate, and combinations thereof;
• composition weight percent of a perchlorate additive including at least one perchlorate material selected from the group consisting of alkali metal perchlorates and ammonium perchlorate; and 1 to 20 composition weight percent of a polymeric binder material selected from the group consisting of cellulosic materials, natural gums, polyacrylates, polyacrylamides, polyurethanes, polybutadienes, polystyrenes, polyvinyl alcohols, polyvinyl acetates, silicones and combinations of two or more thereof.
• a perchlorate additive including at least one perchlorate material selected from the group consisting of alkali metal perchlorates and ammonium perchlorate
• a polymeric binder material selected from the group consisting of cellulosic materials, natural gums, polyacrylates, polyacrylamides, polyurethanes, polybutadienes, polystyrenes, polyvinyl alcohols, polyvinyl acetates, silicones and combinations of two or more thereof.
• Such methods typically involve igniting the particular extrudable gas generant composition to produce a quantity of inflation gas, and then inflating the airbag cushion with the inflation gas.
• the term "equivalence ratio” is understood to refer to the ratio of the number of moles of oxygen in a gas generant composition or formulation to the number of moles needed to convert hydrogen to water, carbon to carbon dioxide, and any metal to a thermodynamically predicted metal oxide.
• a gas generant composition having an equivalence ratio greater than 1.0 is over-oxidized
• a gas generant composition having an equivalence ratio less than 1.0 is under-oxidized
• a gas generant composition having an equivalence ratio equal to 1.0 is perfectly oxidized.
• the expression “substantially free of, in reference to possible gaseous effluent constituents such as hydrogen chloride, carbon monoxide, ammonia, nitrogen dioxide and nitric oxide similarly refers to a gaseous effluent or inflation gas that includes such constituent in an amount that is equal to or less than an amount of such constituent permitted by or allowed under current industry standards (USCAR specifications).
• USCAR specifications current industry standards
• the drawing is a simplified schematic, partially broken away, view illustrating the deployment of an airbag cushion from an airbag module assembly within a vehicle interior, in accordance with one embodiment of the invention.
• the present invention provides an improved gas generant composition. More specifically, it has been discovered that a gas generant effluent product can be dramatically improved (e.g., the resulting effluent has a significantly reduced content of undesirable materials such as one or more of carbon monoxide, ammonia, nitrogen dioxide and nitric oxide) via the inclusion, in the gas generant composition, of one or more perchlorate additives.
• a gas generant effluent product can be dramatically improved (e.g., the resulting effluent has a significantly reduced content of undesirable materials such as one or more of carbon monoxide, ammonia, nitrogen dioxide and nitric oxide) via the inclusion, in the gas generant composition, of one or more perchlorate additives.
• gas generant compositions may be rendered extrudable without an undesirable decrease in burn rate through the inclusion of a polymeric binder material and at least one copper-containing compound.
• perchlorate additives are particularly effective oxidizers for gas generant compositions used in the inflation of automobile inflatable restraint systems.
• a filterable copper chloride byproduct is produced that results in a gaseous effluent or inflation gas that has a reduced content of particular undesirable effluent species. Additionally, it has advantageously been found that a filterable copper chloride byproduct is produced that results in a reduction in the level of particulate that exits the inflator device.
• including a perchlorate additive and at least one copper-containing cQmpound in an extrudable gas generant composition does not result in an undesirable increase in the level of carbon monoxide in the gaseous effluent or inflation gas produced upon combustion of such a gas generant composition.
• Such a finding is unexpected in that generally it has been found that including perchlorate additives in a gas generant composition typically results in an increased temperature of combustion which in turn results in the production of increased levels of carbon monoxide in the gaseous effluent or inflation gas.
• thermodynamic prediction computer programs such as the Naval Weapons Center Propellant Evaluation Program (PEP) generally predict the principal chlorine species in the gaseous effluent or inflation gas produced by the combustion of such an extrudable gas generant composition to be cuprous chloride (CuCl) and a trimer of cuprous chloride (Cu 3 Cl 3 ) with some hydrogen chloride.
• PEP Naval Weapons Center Propellant Evaluation Program
• the inclusion of a polymeric binder material in an amount effective to render a gas generant composition extrudable can normally have a deleterious effect upon the burn rate of the extrudable gas generant composition.
• the burn rates of extrudable gas generant compositions in accordance with the invention can also be improved. Such improved burn rates may be obtained as a result of catalyzing the decomposition of the perchlorate additive without adversely affecting the quality of the gaseous effluent.
• the present invention is directed to an extrudable gas generant composition including at least one non-azide, organic nitrogen-containing fuel, at least one copper-containing compound, a perchlorate additive, and a polymeric binder material effective to render the gas generant composition extrudable.
• the perchlorate additive is present in an amount effective to result in a gaseous effluent, when the gas generant composition is combusted, having a reduced content of at least one species selected from the groups consisting of carbon monoxide, ammonia, nitrogen dioxide and nitric oxide, as compared to a same gas generant composition free of the perchlorate additive.
• the extrudable gas generant composition can include about 5 to about 60 composition weight percent of at least one non-azide, organic nitrogen-containing fuel, about 10 to about 80 composition weight percent of at least one copper-containing compound, about 1 to about 20 composition weight percent of a perchlorate additive, and about 1 to about 20 composition weight percent of a polymeric binder material.
• Useful non-azide, organic, nitrogen-containing fuels for use in the extrudable gas generant composition include: amine nitrates, nitramines, heterocyclic nitro compounds, tetrazole compounds, and combinations thereof.
• non-azide, organic, nitrogen-containing fuels may be used in the extrudable gas generant composition
• the non-azide, organic, nitrogen-containing fuel may advantageously be guanidine nitrate.
• guanidine nitrate may be desirable due to its good thermal stability, low cost and high gas yield when combusted.
• the extrudable gas generant composition can include about 5 to about 60 composition weight percent of at least one non-azide, organic, nitrogen-containing fuel. In accordance with certain embodiments, the extrudable gas generant composition can include about 5 to about 30 composition weight percent of at least one non-azide, organic, nitrogen- containing fuel. In accordance with certain other embodiments, the extrudable gas generant composition can include about 5 to about 20 composition weight percent of at least one non- • azide, organic nitrogen-containing fuel.
• the gas generant composition may include about 5 to about 60 composition weight percent guanidine nitrate. In a further embodiment, the gas generant composition may include about 5 about 30 composition weight percent guanidine nitrate. In a still further embodiment, the gas generant composition may include about 5 to about 20 composition weight percent guanidine nitrate.
• the extrudable gas generant composition also includes at least one copper- containing compound. While various copper-containing compounds may be used in the extrudable gas generant composition, suitably the copper-containing compound is selected from copper-nitrate complexes (such as a copper-nitrate complex resulting from reaction of 5-aminotetrazole with basic copper nitrate), basic copper nitrate, cupric oxide, copper dinitrate-ammonium nitrate mixture wherein ammonium nitrate is present in the mixture in a range of about 3 to about 90 weight percent, copper diammine bitetrazole, and combinations thereof.
• copper-nitrate complexes such as a copper-nitrate complex resulting from reaction of 5-aminotetrazole with basic copper nitrate
• basic copper nitrate basic copper nitrate
• cupric oxide copper dinitrate-ammonium nitrate mixture wherein ammonium nitrate is present in the mixture in a range of about 3 to about 90 weight percent
• the extrudable gas generant composition can include about 10 to about 80 composition weight percent of at least one copper-containing compound.
• One suitable copper-containing compound for use in the practice of this invention includes a copper-nitrate complex resulting from reaction of 5-aminotetrazole with basic copper nitrate.
• the copper-nitrate complex resulting from reaction of 5-aminotetrazole with basic copper nitrate is believed to be a copper, hydroxy nitrate lH-tetrazol-5-amine complex.
• the extrudable gas generant composition may include about 10 to about 60 composition weight percent of a copper-nitrate complex resulting from reaction of 5-aminotetrazole with basic copper nitrate. In accordance with another embodiment, the extrudable gas generant composition may include about 20 to about 60 composition weight percent of a copper-nitrate complex resulting from reaction of 5-aminotetrazole with basic copper nitrate. In a further embodiment, the gas generant composition can include about 30 to about 60 composition weight percent of a copper-nitrate complex resulting from reaction of 5-aminotetrazole with basic copper nitrate.
• the extrudable gas generant composition may include a combination of basic copper nitrate and a copper-nitrate complex resulting from reaction of 5-aminotetrazole with basic copper nitrate.
• the copper-nitrate complex resulting from reaction of 5-aminotetrazole with basic copper nitrate is believed to be a copper, hydroxy nitrate lH-tetrazol-5-amine complex.
• the gas generant composition can include about 10 to about 80 composition weight percent of such combination of basic copper nitrate and the copper-nitrate complex. In accordance with another embodiment, the extrudable gas generant composition may include about 30 to about 80 composition weight percent of such combination of basic copper nitrate and the copper-nitrate complex. In a further embodiment, the extrudable gas generant composition may include about 50 to about 80 composition weight
• the combination of basic copper nitrate and the copper-nitrate complex resulting from reaction of 5-aminotetrazole with basic copper nitrate includes about 20 to about 80 weight percent basic copper nitrate based on the total weight of the combination and about 20 to about 80 weight percent of the copper-nitrate complex based on total weight of the combination.
• the combination of basic copper nitrate and the copper-nitrate complex includes about 20 to about 40 weight percent basic copper nitrate based on the total weight of the combination and about 60 to about 80 weight percent of the copper-nitrate complex based on total weight of the combination.
• the extrudable gas generant compositions further include a perchlorate additive present in an amount effective to result in a gaseous effluent, when the gas generant composition is combusted, having a reduced content of at least one species selected from carbon monoxide, ammonia, nitrogen dioxide and nitric oxide, as compared to a same gas generant composition free of the perchlorate additive.
• the perchlorate additive includes at least one perchlorate material selected from alkali metal perchlorates and ammonium perchlorate.
• the gas generant composition can include about 1 to about 10 composition weight perchlorate additive.
• the perchlorate additive includes at least one alkali metal perchlorate such as, for example, perchlorates of lithium, sodium, potassium, rubidium and cesium.
• alkali metal perchlorate such as, for example, perchlorates of lithium, sodium, potassium, rubidium and cesium.
• sodium perchlorate and potassium perchlorate are believed to be particularly desirable alkali metal perchlorates for use in the practice of the
• the perchlorate additive is ammonium perchlorate.
• the gas generant composition can include about 1 to about 10 composition weight percent ammonium perchlorate.
• perchlorate additives having a mean particle size in excess of 100 microns and, in accordance with certain embodiments, a mean particle size of at least about 200 microns can dramatically improve the effluent resulting from the combustion of an extrudable gas generant composition which includes such sized perchlorate additive particles, as compared to the effluent resulting from the combustion of the same gas generant composition but without the so sized perchlorate additive particles.
• perchlorate additive particles included in extrudable gas generant compositions have a mean particle size in the range of about 350 to about 450 microns.
• the extrudable gas generant composition further includes a polymeric binder material effective to render the gas generant composition extrudable.
• the extrudable gas generant composition includes about 1 to about 20 composition weight percent polymeric binder material.
• the extrudable gas generant composition can include about 3 to about 10 composition weight percent polymeric binder material.
• the extrudable gas generant composition includes about 3 to about 6 composition weight percent polymeric binder material.
• Suitable polymeric binder materials for use in the extrudable gas generant composition include, but are not limited to, cellulosic materials, natural gums, polyacrylates, polyacrylamides, polyurethanes, polybutadienes, polystyrenes, polyvinyl alcohols, polyvinyl acetates, silicones and combinations of two or more thereof.
• the polymeric binder material may be a cellulosic material selected from ethyl cellulose, carboxymethyl cellulose, hydroxypropyl cellulose and combinations of two or more thereof.
• the polymeric binder material maybe a natural gum selected from guar, xanthan, arabic and combination of two or more thereof.
• the gas generant composition includes guar gum such as in a relative amount of about 1 to about 20 composition weight percent.
• the extrudable gas generant composition can include about 3 to about 10 composition weight percent guar gum.
• the extrudable gas generant composition includes about 3 to about 6 composition weight percent guar gum.
• an extrudable gas generant composition in accordance with the invention may advantageously contain at least one metal oxide burn rate enhancing and slag formation additive. Such metal oxide additives may be added to enhance the burn rate of the extrudable gas generant composition or may be added to assist in the removal of undesirable combustion byproducts by forming filterable particulate material or slag.
• the extrudable gas generant compositions of the present invention may include up to about 10 composition weight percent of at least one such metal oxide additive.
• Suitable metal oxide additives include, but are not limited to, silicon dioxide, aluminum oxide, zinc oxide, and combinations thereof.
• the extrudable gas generant compositions include about 1 to about 5 composition weight percent of at least one such metal oxide additive.
• Extrudable gas generant compositions in accordance with certain other embodiments desirably contain about 1.5 to about 5 composition weight percent of aluminum oxide metal oxide burn rate enhancing and slag formation additive and up to about 1 composition weight percent of silicon dioxide metal oxide burn rate enhancing and slag formation additive.
• the extrudabl e gas generant composition may desirably include at least one compound effective to enhance the combustion of theperchlorate additive.
• the extrudable gas generant compositions of the present invention may include up to about 10 composition weight percent of at least one such combustion enhancer.
• Suitable perchlorate additive combustion enhancers include, but are not limited to, iron oxide, copper chromite, ferricyanide/ferrocyanide pigments, and combinations thereof.
• the extrudable gas generant advantageously includes at least one ferricyanide/ferrocyanidepigment.
• ferricyanide/ferrocyanide pigments also referred to as "Iron Blue Pigments” are to be understood to generally refer to that class, family or variety of pigment materials based on microcrystalline Fe(II)Fe(III) cyano complexes. According to results obtained by X-ray and infrared spectroscopy, the basic general chemical formula for the Iron Blue Pigments is believed to be: Me(I)Fe(II)Fe(III)(CNVH 2 O. (1)
• Me(I) stands for potassium, sodium or ammonium, with the alkali ion being believed to play a decisive role in the color properties of Iron Blue.
• Iron Blue Pigments also sometimes referred to as “iron ferricyanides,” have been produced or sold under a variety of different names related to either the place where the compound was made or to represent particular optical properties. Examples of such different names include: “Berlin Blue”,
• Additional additives such as processing aids and/or lubricants may also be included in the extrudable gas generant composition to improve processability of the composition.
• processing aids and/or lubricants may also be included in the extrudable gas generant composition to improve processability of the composition.
• additives may be included in the extrudable gas generant composition in relatively minor concentrations such as no more than about 5 composition weight percent.
• an extrudable gas generant composition in accordance with certain embodiments may include: at least one non-azide, organic, nitrogen-containing fuel present in a relative amount of 5 to 60 composition weight percent; at least one copper-containing compound selected from basic copper nitrate, cupric oxide, a copper diammine dinitrate-ammonium nitrate mixture wherein ammonium nitrate is present in the mixture in a range of about 3 to 90 weight percent, copper diammine bitetrazole, a copper-nitrate complex resulting from reaction of 5-aminotetrazole with basic copper nitrate, and combinations thereof, the at least one copper-containing compound present in a relative amount of 10 to 80 composition weight percent; a perchlorate additive including at least one perchlorate material selected from alkali metal perchlorates and ammonium perchlorate, the perchlorate additive present in a relative amount of 1 to 10 composition weight percent and effective to result in a gaseous effluent, when the gas generant composition
• an extrudable gas generant composition in accordance with certain other embodiments may include 5 to 60 composition weight percent guanidine nitrate, 10 to 80 composition weight percent of a combination of basic copper nitrate and a copper-nitrate complex resulting from reaction of 5-aminotetrazole with basic copper nitrate, 1 to 10 composition weight percent ammonium perchlorate, and 1 to 20 composition weight percent guar gum.
• ammonium perchlorate is effective to result in a gaseous effluent, when the gas generant composition is combusted, having a reduced content of at least one species selected from carbon monoxide, ammonia, nitrogen dioxide and nitric oxide, as compared to a same gas generant composition free of ammonium perchlorate.
• an extrudable gas generant composition in accordance with certain other embodiments may include 5 to 60 composition weight percent guanidine nitrate, 10 to 60 composition weight percent of a copper-nitrate complex resulting from reaction of 5-aminotetrazole with basic copper nitrate, 1 to 10 composition weight percent ammonium perchlorate, and 1 to 20 composition weight percent guar gum.
• the invention further comprehends methods for inflating an airbag cushion of an inflatable restraint system of a motor vehicle including the steps of igniting an extruded gas generant composition to produce a quantity of inflation gas and then inflating the airbag cushion with the inflation gas.
• the inflation gas has a reduced content of at least one species selected from carbon monoxide, ammonia, nitrogen dioxide and nitric oxide.
• extrudable gas generant compositions in accordance with the invention can be incorporated, utilized or practiced in conjunction, with a variety of different structures, assemblies and systems.
• the drawing illustrates a vehicle 10 having an interior 12 wherein an inflatable vehicle occupant safety restraint system, generally designated by the reference numeral 14, is positioned.
• certain standard elements not necessary for an understanding of the invention may have been omitted or removed from the drawing for purposes of facilitating illustration and comprehension.
• the vehicle occupant safety restraint system 14 includes an open-mouthed reaction canister 16 which forms a housing for an inflatable vehicle occupant restraint 20, e.g., an inflatable airbag cushion, and an apparatus, generally designated by the reference numeral 22, for generating or supplying inflation gas for the inflation of an associated occupant restraint.
• an inflatable vehicle occupant restraint 20 e.g., an inflatable airbag cushion
• an apparatus generally designated by the reference numeral 22 for generating or supplying inflation gas for the inflation of an associated occupant restraint.
• an inflator is commonly referred to as an "inflator.”
• the inflator 22 contains a quantity of a gas generant composition in accordance with the invention and such as described above.
• the inflator 22 also includes an ignitor, such as known in the art, for initiating combustion of the gas generant composition in ignition communication with the gas generant composition.
• an ignitor such as known in the art
• the specific construction of the inflator device does not form a limitation on the broader practice of the invention and such inflator devices can be variously constructed such as is also known in the art.
• the airbag cushion 20 upon deployment desirably provides for the protection of a vehicle occupant 24 by restraining movement of the occupant in a direction toward the front of the vehicle, i.e., in the direction toward the right as viewed in the drawing.
• Example 1 EX 1
• Comparative Examples 1-4 CEl - CE4
• 5-ATN/bCN a copper-nitrate complex resulting from reaction of
• Comparative Example 3 Comparative Example 4, and Example 1 were prepared by slurry mixing the guanidine nitrate, the copper-containing compounds and the aluminum oxide. The resulting slurry was spray dried to form a powder precursor. The powder precursor was dry blended with the guar gum and, for Example 1, the ammonium perchlorate. The diy blend mixture was wetted with water, dried and granulated. The resulting granulated mixture was then appropriately tableted using common tableting processing.
• the burn rate data was obtained by first pressing samples of the respective gas generant compositions into the shape or form of a 0.5 inch diameter cylinder. Typically, enough composition was used to result in a cylinder length of 0.5 inch. The cylinders were then each coated on all surfaces except the top surface with a krylon ignition inhibitor to help ensure a linear burn in the test apparatus. In each case, the so- coated cylinders were placed in a 1 -liter closed vessel or test chamber capable of being pressurized to several thousand psi with nitrogen and equipped with a pressure transducer for accurate measurement of test chamber pressure.
• a small sample of igniter powder was placed on top of the cylinder and a nichrome wire was passed through the igniter powder and connected to electrodes mounted in the lid of the test chamber.
• the test chamber was then pressurized to the desired pressure and the sample ignited by passing a current through the nichrome wire.
• Pressure versus time data was collected as each of the respective samples were burned. Since combustion of each of the samples generated gas, an increase in test chamber pressure signaled the start of combustion and a "leveling off' of pressure signaled the end of combustion.
• the time required for combustion was equal to t 2 -t,, where t 2 is the time at the end of combustion and t, is the time at the start of combustion.
• the sample weight was divided by combustion time to determine the burning rate in grams per second.
• the inclusion of guar gum has a deleterious impact on the burn rate of the gas generant composition.
• the burn rate declined from 0.82 inches/second to 0.33 inches/second (about 2.08 cm/second to about 0.84 cm/second).
• an extrudable gas generant composition such as that of Example 1 has both an improved effluent profile and an improved burn rate over extrudable and non-extrudable gas generant compositions which are free of ammonium perchlorate such as, for example, those gas generant compositions described in Comparative Examples 1-4.

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• Feeding, Discharge, Calcimining, Fusing, And Gas-Generation Devices (AREA)

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• 2006
  • 2006-08-28 US US11/511,193 patent/US20060289096A1/en not_active Abandoned
• 2007
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  • 2007-08-16 JP JP2009526617A patent/JP2010502544A/ja active Pending
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• 2008
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