EP0763511A2 - Igniter compositions for non-azide gas generants - Google Patents
Igniter compositions for non-azide gas generants Download PDFInfo
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- EP0763511A2 EP0763511A2 EP96306440A EP96306440A EP0763511A2 EP 0763511 A2 EP0763511 A2 EP 0763511A2 EP 96306440 A EP96306440 A EP 96306440A EP 96306440 A EP96306440 A EP 96306440A EP 0763511 A2 EP0763511 A2 EP 0763511A2
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- EP
- European Patent Office
- Prior art keywords
- fuel
- composition according
- igniter
- composition
- oxygen
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- 239000000203 mixture Substances 0.000 title claims abstract description 89
- 150000001540 azides Chemical class 0.000 title abstract description 8
- 239000007789 gas Substances 0.000 claims abstract description 49
- 239000000446 fuel Substances 0.000 claims abstract description 47
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 17
- 239000007800 oxidant agent Substances 0.000 claims abstract description 16
- 238000002485 combustion reaction Methods 0.000 claims abstract description 15
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 14
- 239000001301 oxygen Substances 0.000 claims abstract description 14
- 229910000048 titanium hydride Inorganic materials 0.000 claims abstract description 12
- 229910001487 potassium perchlorate Inorganic materials 0.000 claims abstract description 10
- BAZAXWOYCMUHIX-UHFFFAOYSA-M sodium perchlorate Chemical compound [Na+].[O-]Cl(=O)(=O)=O BAZAXWOYCMUHIX-UHFFFAOYSA-M 0.000 claims abstract description 5
- 229910001488 sodium perchlorate Inorganic materials 0.000 claims abstract description 5
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 4
- 229910052719 titanium Inorganic materials 0.000 claims abstract description 4
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 12
- 229910052757 nitrogen Inorganic materials 0.000 claims description 7
- 229910052799 carbon Inorganic materials 0.000 claims description 5
- 229910052739 hydrogen Inorganic materials 0.000 claims description 5
- OFOBLEOULBTSOW-UHFFFAOYSA-N Malonic acid Chemical compound OC(=O)CC(O)=O OFOBLEOULBTSOW-UHFFFAOYSA-N 0.000 claims description 4
- 229910052796 boron Inorganic materials 0.000 claims description 4
- 125000004435 hydrogen atom Chemical class [H]* 0.000 claims description 3
- GUBGYTABKSRVRQ-XLOQQCSPSA-N Alpha-Lactose Chemical compound O[C@@H]1[C@@H](O)[C@@H](O)[C@@H](CO)O[C@H]1O[C@@H]1[C@@H](CO)O[C@H](O)[C@H](O)[C@H]1O GUBGYTABKSRVRQ-XLOQQCSPSA-N 0.000 claims description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 2
- FEWJPZIEWOKRBE-JCYAYHJZSA-N Dextrotartaric acid Chemical compound OC(=O)[C@H](O)[C@@H](O)C(O)=O FEWJPZIEWOKRBE-JCYAYHJZSA-N 0.000 claims description 2
- GUBGYTABKSRVRQ-QKKXKWKRSA-N Lactose Natural products OC[C@H]1O[C@@H](O[C@H]2[C@H](O)[C@@H](O)C(O)O[C@@H]2CO)[C@H](O)[C@@H](O)[C@H]1O GUBGYTABKSRVRQ-QKKXKWKRSA-N 0.000 claims description 2
- KDYFGRWQOYBRFD-UHFFFAOYSA-N Succinic acid Natural products OC(=O)CCC(O)=O KDYFGRWQOYBRFD-UHFFFAOYSA-N 0.000 claims description 2
- FEWJPZIEWOKRBE-UHFFFAOYSA-N Tartaric acid Natural products [H+].[H+].[O-]C(=O)C(O)C(O)C([O-])=O FEWJPZIEWOKRBE-UHFFFAOYSA-N 0.000 claims description 2
- KDYFGRWQOYBRFD-NUQCWPJISA-N butanedioic acid Chemical compound O[14C](=O)CC[14C](O)=O KDYFGRWQOYBRFD-NUQCWPJISA-N 0.000 claims description 2
- 239000001257 hydrogen Substances 0.000 claims description 2
- 239000008101 lactose Substances 0.000 claims description 2
- 235000002906 tartaric acid Nutrition 0.000 claims description 2
- 239000011975 tartaric acid Substances 0.000 claims description 2
- 230000000977 initiatory effect Effects 0.000 claims 1
- 150000001720 carbohydrates Chemical class 0.000 abstract description 8
- 229910052749 magnesium Inorganic materials 0.000 abstract description 3
- BZSXEZOLBIJVQK-UHFFFAOYSA-N 2-methylsulfonylbenzoic acid Chemical compound CS(=O)(=O)C1=CC=CC=C1C(O)=O BZSXEZOLBIJVQK-UHFFFAOYSA-N 0.000 abstract description 2
- 231100000331 toxic Toxicity 0.000 abstract description 2
- 230000002588 toxic effect Effects 0.000 abstract description 2
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 abstract 2
- 239000011591 potassium Substances 0.000 abstract 2
- 229910052700 potassium Inorganic materials 0.000 abstract 1
- FGIUAXJPYTZDNR-UHFFFAOYSA-N potassium nitrate Chemical compound [K+].[O-][N+]([O-])=O FGIUAXJPYTZDNR-UHFFFAOYSA-N 0.000 description 10
- 239000000463 material Substances 0.000 description 8
- PXIPVTKHYLBLMZ-UHFFFAOYSA-N Sodium azide Chemical compound [Na+].[N-]=[N+]=[N-] PXIPVTKHYLBLMZ-UHFFFAOYSA-N 0.000 description 6
- 239000002341 toxic gas Substances 0.000 description 5
- 239000006227 byproduct Substances 0.000 description 4
- 229910052751 metal Inorganic materials 0.000 description 4
- 239000002184 metal Substances 0.000 description 4
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 3
- 125000004432 carbon atom Chemical group C* 0.000 description 3
- 229910052987 metal hydride Inorganic materials 0.000 description 3
- 150000004681 metal hydrides Chemical class 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- 239000010936 titanium Substances 0.000 description 3
- QPLDLSVMHZLSFG-UHFFFAOYSA-N Copper oxide Chemical compound [Cu]=O QPLDLSVMHZLSFG-UHFFFAOYSA-N 0.000 description 2
- -1 aluminum hydrides Chemical class 0.000 description 2
- AXZAYXJCENRGIM-UHFFFAOYSA-J dipotassium;tetrabromoplatinum(2-) Chemical compound [K+].[K+].[Br-].[Br-].[Br-].[Br-].[Pt+2] AXZAYXJCENRGIM-UHFFFAOYSA-J 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 229910044991 metal oxide Inorganic materials 0.000 description 2
- 150000004706 metal oxides Chemical class 0.000 description 2
- 231100000252 nontoxic Toxicity 0.000 description 2
- 230000003000 nontoxic effect Effects 0.000 description 2
- 125000004430 oxygen atom Chemical group O* 0.000 description 2
- DHEQXMRUPNDRPG-UHFFFAOYSA-N strontium nitrate Chemical compound [Sr+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O DHEQXMRUPNDRPG-UHFFFAOYSA-N 0.000 description 2
- ULRPISSMEBPJLN-UHFFFAOYSA-N 2h-tetrazol-5-amine Chemical compound NC1=NN=NN1 ULRPISSMEBPJLN-UHFFFAOYSA-N 0.000 description 1
- XTEGARKTQYYJKE-UHFFFAOYSA-M Chlorate Chemical class [O-]Cl(=O)=O XTEGARKTQYYJKE-UHFFFAOYSA-M 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 1
- AZDRQVAHHNSJOQ-UHFFFAOYSA-N alumane Chemical class [AlH3] AZDRQVAHHNSJOQ-UHFFFAOYSA-N 0.000 description 1
- 229910052810 boron oxide Inorganic materials 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 229960004643 cupric oxide Drugs 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- JKWMSGQKBLHBQQ-UHFFFAOYSA-N diboron trioxide Chemical compound O=BOB=O JKWMSGQKBLHBQQ-UHFFFAOYSA-N 0.000 description 1
- NDEMNVPZDAFUKN-UHFFFAOYSA-N guanidine;nitric acid Chemical compound NC(N)=N.O[N+]([O-])=O.O[N+]([O-])=O NDEMNVPZDAFUKN-UHFFFAOYSA-N 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 231100001231 less toxic Toxicity 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 125000004433 nitrogen atom Chemical group N* 0.000 description 1
- QJGQUHMNIGDVPM-UHFFFAOYSA-N nitrogen group Chemical group [N] QJGQUHMNIGDVPM-UHFFFAOYSA-N 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- VLTRZXGMWDSKGL-UHFFFAOYSA-N perchloric acid Chemical class OCl(=O)(=O)=O VLTRZXGMWDSKGL-UHFFFAOYSA-N 0.000 description 1
- VKJKEPKFPUWCAS-UHFFFAOYSA-M potassium chlorate Chemical compound [K+].[O-]Cl(=O)=O VKJKEPKFPUWCAS-UHFFFAOYSA-M 0.000 description 1
- 235000010333 potassium nitrate Nutrition 0.000 description 1
- 239000004323 potassium nitrate Substances 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C06—EXPLOSIVES; MATCHES
- C06C—DETONATING OR PRIMING DEVICES; FUSES; CHEMICAL LIGHTERS; PYROPHORIC COMPOSITIONS
- C06C9/00—Chemical contact igniters; Chemical lighters
-
- C—CHEMISTRY; METALLURGY
- C06—EXPLOSIVES; MATCHES
- C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
- C06B33/00—Compositions containing particulate metal, alloy, boron, silicon, selenium or tellurium with at least one oxygen supplying material which is either a metal oxide or a salt, organic or inorganic, capable of yielding a metal oxide
Definitions
- the present invention is directed to compositions for igniting gas generants for use in automotive airbag applications in conjunction with non-azide gas generants, particularly gas generant compositions containing both nitrogen and oxygen atoms and/or both nitrogen and hydrogen atoms and/or both nitrogen and carbon atoms.
- an airbag When an airbag is deployed, it must rapidly inflate, e.g., in the range of between 30 and 100 milliseconds, and then rapidly deflate. During deflation, the gases are vented into the passenger compartment of a vehicle, and undesirable by-product gases may present a hazard to the occupants of the vehicle. This is one of the major impediments in the commercialization of non-azide pyrotechnic inflators.
- a typical automotive airbag system consists of an airbag and a pyrotechnic inflator module in which the gases are produced which inflate the airbag.
- Inflators are described, for example, in U.S. Patents Nos. 4,943,086, 5,221,109, 5,241,910, the teachings of each of which are incorporated herein by reference.
- a remote sensor senses the force of a collision. The sensor is electrically connected to a squib in the inflator, and electrically generated heat in the squib ignites a small charge of pyrotechnic material in the squib. The pyrotechnic charge, in turn, produces heat that sets off a larger charge of igniter composition.
- a very common igniter material is B/KNO 3 , in which boron is the fuel and potassium nitrate the oxidizer.
- This composition is a standard ignitor composition in the inflator industry. This ignitor is generally proportioned to be fuel rich (that is oxygen-poor). Fuel-rich mixtures tend to have high burn temperatures, a feature desirable in igniting a gas generant composition. Furthermore, a fuel (boron)-rich ignitor composition ejects hot particles of boron or boron oxide which hasten combustion of the gas generant composition through direct thermal contact with the gas generant composition to be ignited.
- an igniter composition for a non-azide gas generant composition in which the gas generant composition contains any combination of C, H, O and/or N atoms which results in a reduction of undesired gas by-products produced by combustion of the gas generant composition.
- the igniter composition has a fuel component of which between about 5 and 100 wt% is a fuel selected from Mg, Ti, Al, TiH 2 , and mixtures thereof, and up to about 95 wt% of which comprises a combustible carbohydrate fuel, that is, a fuel which contains only the elements carbon, hydrogen and oxygen. Between about 35 and about 65 wt% of the carbohydrate fuel, if used, is oxygen content.
- the igniter composition further comprises an oxidizer component which does not contain nitrogen, particularly an oxidizer selected from the group consisting of KClO 3 , NaClO 3 , KClO 4 , NaClO 4 , and mixtures thereof.
- the igniter composition in accordance with the present invention is designed to burn with a sufficiently high temperature to ignite the gas generant composition.
- the igniter composition like the gas generant composition, produces gases upon combustion, this is not its primary purpose; hence, igniter compositions are not necessarily selected to maximize their gas output.
- the igniter composition is used at a very low mass ratio relative to the gas generant.
- a typical automotive driver side airbag inflator may contain about 2 grams of igniter composition and about 60 to 100 grams of gas generant composition. Passenger- side airbags and side airbags may have different amounts of gas generant material, but likewise contain a greater amount of gas generant material relative to igniter material.
- Non-azide gas generant compositions to which the invention is directed are those which contain the combinations of N plus O and/or N plus H, giving rise to NO x (especially NO and NO 2 ) and NH 3 combustion products.
- Such gas generant compositions commonly also contain carbon atoms, further giving rise to CO and HCN combustion products.
- the igniter composition contains oxidizer component in an amount sufficient so as to be at least stoichiometrically balanced with the fuel, i.e., have an oxygen-to-fuel ratio (O/F) of at least 1, and preferably is oxygen-rich, having an O/F stoichiometric ratio of at least about 1.05.
- the igniter composition must have an O/F ratio consistent with providing sufficient energy to ignite the gas generant composition.
- the igniter composition must be least stoichiometrically balanced. That is, there must be sufficient oxidizer to oxidize the metal or metal-containing fuel to the appropriate metal oxide and any carbohydrate fuel to CO 2 and H 2 O.
- the oxidizer-to-fuel ratio (O/F) is defined as equal to 1.0. If there is a 5% excess of oxidizer the O/F ratio is 1.05 and so forth.
- Preferred compositions have O/F greater than 1.05. This is in contrast to conventional B/KNO 3 igniter composition which is fuel rich (oxygen deficient).
- the combustion temperatures of the igniter compositions of the present invention are sufficiently high to ignite most non-azide gas generant compositions.
- the upper limit of O/F ratio is the point where the igniter composition no longer combusts hot enough to ignite the gas generant composition.
- igniter compositions in accordance with the invention will have O/F limits no higher than about 1.3 (i.e. 30 molar% over-oxidized).
- the fuel component may be entirely a metal or a metal hydride selected from the group consisting of Mg, Ti, Al, TiH 2 , and mixtures thereof. Of these, Ti is least preferred due to associated health risks. Mg and TiH 2 are currently preferred. While other metal hydrides, such as aluminum hydrides, might work as igniter fuels, they are generally considered to be too moisture-sensitive for automotive airbag inflators. TiH 2 , however, is found to have good moisture stability. Metals and metal hydrides have the important function in igniter compositions as producing metal oxide particulates, such as aluminum oxide or titanium oxide. Such particulates contribute to a rapid initial pressure by heating the gas generant composition by direct conduction.
- the fuel component may also include an organic C, H, O compound (carbohydrate) fuel having a relatively high oxygen content, i.e., between about 35 and about 65 wt%.
- the oxygen component is preferably high so as to require a relatively low corresponding amount of oxygen in the igniter mixture.
- the carbohydrate fuel is generally used at a level of at least about 20 wt% of the fuel component, more typically at a level of at least about 50 wt% of the fuel component, and most typically at a level of at least about 60 wt% of the fuel component, up to about 95% of the fuel component.
- the carbohydrate fuel if used, is included to produce high volumes of gas and therefore contribute to an initial high gas pressure within the inflator module, high pressure being believed to reduce levels of toxic gases.
- suitable carbohydrate fuels include, but are not limited to tartaric acid, succinic acid, malonic acid, lactose and mixtures thereof.
- the oxidizer component is a non-nitrogen-containing oxidizer.
- Preferred oxidizers are chlorates and perchlorates, such as potassium chlorate, sodium chlorate, potassium perchlorate, sodium perchlorate, or mixtures thereof.
- the identical composition was ignited using titanium hydride/potassium perchlorate (TiH 2 /KClO 4 ) igniter compositions with varying O/F ratios.
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Air Bags (AREA)
Abstract
Description
- The present invention is directed to compositions for igniting gas generants for use in automotive airbag applications in conjunction with non-azide gas generants, particularly gas generant compositions containing both nitrogen and oxygen atoms and/or both nitrogen and hydrogen atoms and/or both nitrogen and carbon atoms.
- Most present-day automotive airbag inflators use a gas generant based on sodium azide. This material has the advantage of producing, upon combustion, pure non-toxic nitrogen as a gaseous combustion product. However, sodium azide as a raw material is toxic, presenting disposal problems.
- Accordingly, there has been a desire to replace sodium azide with less toxic gas generant compositions. A number of such gas generant compositions have been described, for example, in U.S. Patents Nos. 3,468,730, 5,084,118, and 5,035,757, the teachings of each of which are incorporated herein by reference. The combustion of most non-azide gas generant compositions, which contain the elements C, H, O, and N, produce generally non-toxic gases (N2, H2O, and/or CO2); however, they also tend to produce undesirable gas by-products, such as NH3, NOx, CO, and HCN, each of which may be harmful in the range of 25 to 1000 ppm. When an airbag is deployed, it must rapidly inflate, e.g., in the range of between 30 and 100 milliseconds, and then rapidly deflate. During deflation, the gases are vented into the passenger compartment of a vehicle, and undesirable by-product gases may present a hazard to the occupants of the vehicle. This is one of the major impediments in the commercialization of non-azide pyrotechnic inflators.
- A typical automotive airbag system consists of an airbag and a pyrotechnic inflator module in which the gases are produced which inflate the airbag. Inflators, are described, for example, in U.S. Patents Nos. 4,943,086, 5,221,109, 5,241,910, the teachings of each of which are incorporated herein by reference. In a typical airbag inflator deployment system, a remote sensor senses the force of a collision. The sensor is electrically connected to a squib in the inflator, and electrically generated heat in the squib ignites a small charge of pyrotechnic material in the squib. The pyrotechnic charge, in turn, produces heat that sets off a larger charge of igniter composition. The heat from the igniter composition then sets off a much larger charge of gas generant composition that produces substantial volumes of gases for inflating the airbag. It is also understood that there are variations of this typical system to which the present invention is applicable; for example, hybrid inflators which inflate airbags with a combination of pyrotechnic- generated gases and compressed gases, such as that described in U.S. Patent No. 5,290,060, the teachings of which are incorporated herein by reference.
- A very common igniter material is B/KNO3, in which boron is the fuel and potassium nitrate the oxidizer. This composition is a standard ignitor composition in the inflator industry. This ignitor is generally proportioned to be fuel rich (that is oxygen-poor). Fuel-rich mixtures tend to have high burn temperatures, a feature desirable in igniting a gas generant composition. Furthermore, a fuel (boron)-rich ignitor composition ejects hot particles of boron or boron oxide which hasten combustion of the gas generant composition through direct thermal contact with the gas generant composition to be ignited.
- In accordance with the present invention there is provided an igniter composition for a non-azide gas generant composition in which the gas generant composition contains any combination of C, H, O and/or N atoms which results in a reduction of undesired gas by-products produced by combustion of the gas generant composition. The igniter composition has a fuel component of which between about 5 and 100 wt% is a fuel selected from Mg, Ti, Al, TiH2, and mixtures thereof, and up to about 95 wt% of which comprises a combustible carbohydrate fuel, that is, a fuel which contains only the elements carbon, hydrogen and oxygen. Between about 35 and about 65 wt% of the carbohydrate fuel, if used, is oxygen content. The igniter composition further comprises an oxidizer component which does not contain nitrogen, particularly an oxidizer selected from the group consisting of KClO3, NaClO3, KClO4, NaClO4, and mixtures thereof.
- The igniter composition in accordance with the present invention is designed to burn with a sufficiently high temperature to ignite the gas generant composition. Although, the igniter composition, like the gas generant composition, produces gases upon combustion, this is not its primary purpose; hence, igniter compositions are not necessarily selected to maximize their gas output. The igniter composition is used at a very low mass ratio relative to the gas generant. A typical automotive driver side airbag inflator may contain about 2 grams of igniter composition and about 60 to 100 grams of gas generant composition. Passenger- side airbags and side airbags may have different amounts of gas generant material, but likewise contain a greater amount of gas generant material relative to igniter material.
- While the igniter composition is used at a very low level compared to the gas generant composition, it is surprisingly found that the selection of igniter composition can have a significant effect on the levels of undesirable gas by-products, especially NO4, NH3, CO and/or HCN produced upon combustion of a non-azide gas generant composition. Non-azide gas generant compositions to which the invention is directed are those which contain the combinations of N plus O and/or N plus H, giving rise to NOx (especially NO and NO2) and NH3 combustion products. Such gas generant compositions commonly also contain carbon atoms, further giving rise to CO and HCN combustion products.
- The igniter composition contains oxidizer component in an amount sufficient so as to be at least stoichiometrically balanced with the fuel, i.e., have an oxygen-to-fuel ratio (O/F) of at least 1, and preferably is oxygen-rich, having an O/F stoichiometric ratio of at least about 1.05. The igniter composition must have an O/F ratio consistent with providing sufficient energy to ignite the gas generant composition. The igniter composition must be least stoichiometrically balanced. That is, there must be sufficient oxidizer to oxidize the metal or metal-containing fuel to the appropriate metal oxide and any carbohydrate fuel to CO2 and H2O. When the amount of oxidizer is just sufficient to do this, the oxidizer-to-fuel ratio (O/F) is defined as equal to 1.0. If there is a 5% excess of oxidizer the O/F ratio is 1.05 and so forth. Preferred compositions have O/F greater than 1.05. This is in contrast to conventional B/KNO3 igniter composition which is fuel rich (oxygen deficient).
- While a high O/F ratio tends to lower the combustion temperature of the igniter compositions, the combustion temperatures of the igniter compositions of the present invention are sufficiently high to ignite most non-azide gas generant compositions. For any combination of any particular gas generant composition with any particular igniter composition, the upper limit of O/F ratio is the point where the igniter composition no longer combusts hot enough to ignite the gas generant composition. Generally, igniter compositions in accordance with the invention will have O/F limits no higher than about 1.3 (i.e. 30 molar% over-oxidized).
- Why an oxygen-balanced or oxygen-rich igniter composition should have a significant effect on the levels of toxic gases produced by the gas generant material is not fully understood and applicants are not bound by theory. However, it is found that by using oxygen-balanced or oxygen-rich igniter compositions in accordance with the present invention, gas pressure in the inflator rises much more rapidly than when oxygen-poor igniter materials are used. Experience has shown that low-pressure combustion favors higher production of certain toxic gases, such as NOx, CO, HCN, and NH3 and that high-pressure combustion produces less of such gases. It may also be that, in preferred oxygen-rich igniter compositions, the slight amount of additional oxygen serves to favor oxidation of the undesired gases, such as CO to CO2 or NH3 to N2 and H2O.
- The fuel component may be entirely a metal or a metal hydride selected from the group consisting of Mg, Ti, Al, TiH2, and mixtures thereof. Of these, Ti is least preferred due to associated health risks. Mg and TiH2 are currently preferred. While other metal hydrides, such as aluminum hydrides, might work as igniter fuels, they are generally considered to be too moisture-sensitive for automotive airbag inflators. TiH2, however, is found to have good moisture stability. Metals and metal hydrides have the important function in igniter compositions as producing metal oxide particulates, such as aluminum oxide or titanium oxide. Such particulates contribute to a rapid initial pressure by heating the gas generant composition by direct conduction.
- The fuel component may also include an organic C, H, O compound (carbohydrate) fuel having a relatively high oxygen content, i.e., between about 35 and about 65 wt%. The oxygen component is preferably high so as to require a relatively low corresponding amount of oxygen in the igniter mixture. If used, the carbohydrate fuel is generally used at a level of at least about 20 wt% of the fuel component, more typically at a level of at least about 50 wt% of the fuel component, and most typically at a level of at least about 60 wt% of the fuel component, up to about 95% of the fuel component. The carbohydrate fuel, if used, is included to produce high volumes of gas and therefore contribute to an initial high gas pressure within the inflator module, high pressure being believed to reduce levels of toxic gases. Some suitable carbohydrate fuels include, but are not limited to tartaric acid, succinic acid, malonic acid, lactose and mixtures thereof.
- The oxidizer component is a non-nitrogen-containing oxidizer. Preferred oxidizers are chlorates and perchlorates, such as potassium chlorate, sodium chlorate, potassium perchlorate, sodium perchlorate, or mixtures thereof.
- The invention will now be described in greater detail by way of specific examples.
- A gas generant composition formed of 5-aminotetrazole, cupric oxide, strontium nitrate and guanidine nitrate, of the type described in U.S. Patent No. 5,431,103, the teaching of which are incorporated herein by reference, were ignited with (as a control) a B/KNO3 igniter composition having an O/F ratio of 0.54. The identical composition was ignited using titanium hydride/potassium perchlorate (TiH2/KClO4) igniter compositions with varying O/F ratios. Results are shown in the table below:
Composition O/F NOx (ppm) NH3 (ppm) CO (ppm) HCN (ppm) B/KNO3 88 282 198 10 TiH2/KClO4 0.85 71 183 264 11 TiH2/KClO4 1.30 70 164 274 8 TiH2/KClO4 1.45 71 142 193 5
Claims (16)
- An igniter composition comprisingA) a fuel component, between 5 wt% and 100 wt% of said fuel component being selected from Mg, TiH2, Al, Ti, and mixtures thereof, and up to 95 wt% of said fuel component comprising an organic fuel which contains only the elements carbon, hydrogen, and oxygen, said organic fuel having an oxygen content of between 35 and 65 wt%, andB) an oxidizer component which contains no nitrogen,said igniter composition having an oxygen-to-fuel ratio of at least 1:1.
- A composition according to Claim 1 wherein said oxygen-to-fuel ratio is at least 1.05:1.
- A composition according to Claim 1 or Claim 2 wherein said fuel component comprises TiH2.
- A composition according to Claim 1 or Claim 2 wherein said fuel component comprises Mg.
- A composition according to Claim 1 or Claim 2 wherein said fuel component comprises Ti.
- A composition according to Claim 1 or Claim 2 wherein said fuel component comprises Al.
- A composition according to any preceding claim wherein said oxidizer is selected from KClO4, NaClO4, NaClO3, and KClO3 and mixtures thereof.
- A composition according to Claim 7 wherein said oxidizer component comprises KClO4.
- A composition according to Claim 7 wherein said oxidizer component comprises NaClO4.
- A composition according to Claim 7 wherein said oxidizer component comprises KClO3.
- A composition according to Claim 7 wherein said oxidizer component comprises NaClO3.
- A composition according to any preceding claim wherein said organic fuel is present at between 20 and 95 wt% of said fuel component.
- A composition according to Claim 12 wherein said organic fuel is present at between 50 and 95 wt% of said fuel component.
- A composition according to Claim 13 wherein said organic fuel is present at between 60 and 95 wt% of said fuel component.
- A composition according to any preceding claim wherein said organic fuel is selected from tartaric acid, succinic acid, malonic acid, lactose, and mixtures thereof.
- An automotive airbag inflator module containing a generant combustible for producing gases to inflate an airbag and an igniter composition according to any preceding claim for initiating combustion of said generant.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US52912095A | 1995-09-15 | 1995-09-15 | |
| US529120 | 1995-09-15 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0763511A2 true EP0763511A2 (en) | 1997-03-19 |
| EP0763511A3 EP0763511A3 (en) | 1997-05-07 |
Family
ID=24108609
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP96306440A Withdrawn EP0763511A3 (en) | 1995-09-15 | 1996-09-05 | Igniter compositions for non-azide gas generants |
Country Status (2)
| Country | Link |
|---|---|
| EP (1) | EP0763511A3 (en) |
| JP (1) | JPH09118580A (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2000044691A1 (en) * | 1999-01-27 | 2000-08-03 | Daicel Chemical Industries, Ltd. | METHOD FOR REDUCING NO¿x? |
| WO2000047538A3 (en) * | 1999-02-02 | 2000-12-21 | Ivan V Mendenhall | Low particulate igniter composition for a gas generant |
| DE10204834A1 (en) * | 2002-02-06 | 2003-08-21 | Trw Airbag Sys Gmbh & Co Kg | Explosive especially for use in igniters for electronic vehicle safety systems comprises a porous (especially silicon) fuel with the oxidizer in the pores |
| EP1666439A3 (en) * | 2004-11-15 | 2006-08-02 | Swell Tech Co., Ltd. | Expansive cell composition for electric rock destruction |
| CN103052609A (en) * | 2010-07-15 | 2013-04-17 | 日本化药株式会社 | Igniting powder composition for igniters |
| US9441451B2 (en) | 2013-08-01 | 2016-09-13 | Halliburton Energy Services, Inc. | Self-setting downhole tool |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1785409A4 (en) | 2004-06-17 | 2010-04-07 | Nof Corp | IGNITION AGENT FOR GAS GENERATING DEVICE |
| JP5156627B2 (en) * | 2005-07-29 | 2013-03-06 | オートモーティブ システムズ ラボラトリィ、 インク. | Self-ignition / booster composition |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB630981A (en) * | 1946-11-22 | 1949-10-25 | Percy Alfred Harry Goldsmith | Improvements in and relating to compositions for ignition of combustible gas producing charges or heating mixtures |
| US3309250A (en) * | 1965-03-24 | 1967-03-14 | Charles W Falterman | Temperature resistant explosive containing titanium and alkali metal perchlorate |
| US3712223A (en) * | 1970-10-07 | 1973-01-23 | R Degn | Pyrotechnic, whistle, and method of making |
| US3785149A (en) * | 1972-06-08 | 1974-01-15 | Specialty Prod Dev Corp | Method for filling a bag with water vapor and carbon dioxide gas |
| US4522665A (en) * | 1984-03-08 | 1985-06-11 | Geo Vann, Inc. | Primer mix, percussion primer and method for initiating combustion |
| CH664554A5 (en) * | 1985-07-15 | 1988-03-15 | Oerlikon Buehrle Ag | Ignition powder mixt. for solid propellant reinforcing charge - contg. inorganic. fuel and excess inorganic oxidant to generate oxygen and prevent hang fire in cold |
| DE4423088A1 (en) * | 1994-07-01 | 1996-01-04 | Temic Bayern Chem Airbag Gmbh | Gas-generating, acid-free mixture of substances |
-
1996
- 1996-09-05 EP EP96306440A patent/EP0763511A3/en not_active Withdrawn
- 1996-09-13 JP JP8243580A patent/JPH09118580A/en active Pending
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2000044691A1 (en) * | 1999-01-27 | 2000-08-03 | Daicel Chemical Industries, Ltd. | METHOD FOR REDUCING NO¿x? |
| WO2000047538A3 (en) * | 1999-02-02 | 2000-12-21 | Ivan V Mendenhall | Low particulate igniter composition for a gas generant |
| DE10204834A1 (en) * | 2002-02-06 | 2003-08-21 | Trw Airbag Sys Gmbh & Co Kg | Explosive especially for use in igniters for electronic vehicle safety systems comprises a porous (especially silicon) fuel with the oxidizer in the pores |
| DE10204834B4 (en) * | 2002-02-06 | 2005-05-25 | Trw Airbag Systems Gmbh & Co. Kg | Explosive composition and process for its preparation |
| US6984274B2 (en) | 2002-02-06 | 2006-01-10 | Trw Airbag Systems Gmbh | Explosive composition and its use |
| EP1666439A3 (en) * | 2004-11-15 | 2006-08-02 | Swell Tech Co., Ltd. | Expansive cell composition for electric rock destruction |
| CN103052609A (en) * | 2010-07-15 | 2013-04-17 | 日本化药株式会社 | Igniting powder composition for igniters |
| EP2594545A4 (en) * | 2010-07-15 | 2014-01-22 | Nippon Kayaku Kk | Igniting powder composition for igniters |
| US9441451B2 (en) | 2013-08-01 | 2016-09-13 | Halliburton Energy Services, Inc. | Self-setting downhole tool |
Also Published As
| Publication number | Publication date |
|---|---|
| EP0763511A3 (en) | 1997-05-07 |
| JPH09118580A (en) | 1997-05-06 |
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