CA2143360A1 - Gas generant compositions with alkali oxide scavengers - Google Patents
Gas generant compositions with alkali oxide scavengersInfo
- Publication number
- CA2143360A1 CA2143360A1 CA002143360A CA2143360A CA2143360A1 CA 2143360 A1 CA2143360 A1 CA 2143360A1 CA 002143360 A CA002143360 A CA 002143360A CA 2143360 A CA2143360 A CA 2143360A CA 2143360 A1 CA2143360 A1 CA 2143360A1
- Authority
- CA
- Canada
- Prior art keywords
- gas generant
- generant composition
- acid
- group
- composition according
- 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.)
- Abandoned
Links
Classifications
-
- 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
-
- 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
-
- C—CHEMISTRY; METALLURGY
- C06—EXPLOSIVES; MATCHES
- C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
- C06B23/00—Compositions characterised by non-explosive or non-thermic constituents
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Combustion & Propulsion (AREA)
- Air Bags (AREA)
- Solid-Sorbent Or Filter-Aiding Compositions (AREA)
Abstract
A gas generant composition adapted for use with airbag restraint systems containing aluminum components includes a fuel which is 5-nitrobarbituric acid (or salts thereof), 5-nitroorotic acid (or salts thereof); an oxidizer which is an ammonium, alkali metal and/or alkaline earth metal salt of a chlorate, perchlorate or nitrate and/or is a transition metal oxide, such as cupric oxide; alumina and/or silica; and a binder.
Description
21g3360 PATENT
GAS GENERANT COMPOSITIONS WITH ALKALI OXIDE SCAVENGERS
The present invention is directed to gas generant compositions suitable for automotive air bag restraint systems, particularly restraint systems in which the gas generant is encased in aluminum housing and/or generates gases which come into contact with aluminum components, such as filters.
Background of the Invention:
Most automotive air bag restraint systems, presently in use, use gas generant compositions in which sodium azide is the principal fuel. Because of disadvantages with sodium azide, particularly instability in the presence of metallic impurities and toxicity, which presents a disposal problem for unfired gas generators, there is a desire to develop non-azide gas generant systems and a number of non-azide formulations have been proposed. However, to date, non-azide gas generants have not made significant commercial inroads.
U.S. Patent No. 5,015,309 to Wardle et al., the teachings of which are incorporated herein by reference, teaches gas generant compositions in which fuels are salts of 5-nitrobarbituric acid, salts of 5-nitroorotic acid and nitrouracil (which doesn't form a salt), oxidizers include alkali (except sodium) and alkaline earth metal salts of nitrates, nitrites and hexanitrocolbatate, and binders, when needed for pelletization.
This patent teaches that minimal amounts of non-gas generating components should be added, except up to 1 wt% fibers, such as graphite or iron fibers, which increase the burning rate and transfer heat during combustion.
, PATENT
The 5,015,309 patent teaches that the compositions are useful for inflators as taught in U.S. Patent No. 4,547,342 to Adams et al., the teachings of which are incorporated herein by reference. The inflators taught in U.S. Patent No. 4,547,342 have aluminum housings and other aluminum components. A
disadvantage with compositions such as taught in the 5,015,309 patent is that combustion products include K2O which is highly corrosive to aluminum. Improved formulations are needed to reduce degradation of aluminum components during combustion of the gas generant composition. Also, it is highly desirable that the combustion products include a slag which is filterable. The compositions taught in the 5,015,309 patent are not filterable.
Summary of the Invention:
A gas generant composition using as the fuel component a compound selected from 5-nitrobarbituric acid, 5-nitroorotic acid, alkali and alkaline earth metal salts thereof; an oxidizer for the fuel selected from ammonium, alkali metal and alkaline earth metal salts of chlorates, perchlorates and nitrates and transition metal oxides; and a binder, also contains alumina (Al2O3) and/or silica (SiO2) as a scavenger of alkali metal oxides.
Detailed Description of Certain Preferred Embodiments:
The fuel comprises between about 20 and about 55 wt% of the gas generant composition. Preferred fuels are the potassium salts of 5-nitrobarbituric acid (also called dilituric acid) and 5-nitroorotic acid.
The oxidizer, which is used at a level of between about 50 and about 75 wt% is selected from ammonium, alkali metal and alkaline earth metal chlorates, perchlorates, nitrates, transition metal oxides, and mixture thereof.
Optionally, a portion of the oxidizer may be a transition PATENT
metal oxide, such as cupric oxide. Such a transition metal oxide preferably comprises between about 5 to about 35 wt~ of the composition. In addition to their oxidizing function, these oxides provide hard particles, facilitating compaction of the composition into pellets or other consolidated solid shapes.
As is taught in U.S. Patent No. 5,139,588, the teachings of which are incorporated herein by reference, the cations of the fuel salts and oxidizers are preferably mixture of alkali metal cations, i.e., lithium, sodium and potassium, and alkaline earth metal cations, i.e., magnesium, strontium, barium and cerium. Upon combustion, the alkali cations form liquid combustion products and the alkaline earth metal cations form solid combustion products, the mixture of liquid and solid combustion products forming clinkers which can be readily removed from the gas stream by filtration. The ratio of solid to liquid combustion products may be adjusted by the ratio of alkaline earth metal cations to alkali metal cations.
Of alkali metal cations, sodium is preferred over potassium as sodium oxide is more readily scavenged by alumina or silica than potassium oxide.
In accordance with the present invention, alumina, silica or mixtures thereof are added to scavenge corrosive alkali metal oxides, such as sodium oxide and potassium oxide. Accordingly, the composition of the present invention contains alumina and/or silica at a level of between about 0.5 and about 10 wt%, preferably between about 1 and about 8 wt%. The alumina and/or silica may be in the form of particulates or as fibers, such as fibers of various silica/alumina content. Alumina is generally preferred over silica, being a more efficient scavenger.
A binder is added at a level of between about 1 and about 5 wt%. Suitable binder materials include but are not limited to molybdenum disulfide, graphite, polytetrafluroethylene, VitonR (a copolymer of vinylidene fluoride and hexafluoropropylene), PATENT
nitrocellulose, polysaccharides, polyvinylpyrrolidones, polycarbonates, sodium silicate, calcium stearate, magnesium stearate and mixtures thereof. Preferred binder materials are molybdenum disulfite and polycarbonates.
Alkali metal and alkaline earth metal carbonates and/or oxalates may optionally be added up to about 40 wt%. These act as coolants, lowering the combustion temperature. Lower combustion temperatures minimize production of toxic gases, such as CO and NOx. Generally, if used, these coolants are used at a lo level of at least about 1 wt%.
As noted above, the alumina and/or silica may be in the form of fibers. Fibers help to mechanically reinforce the consolidated unburned material and subsequently consolidate slag material formed by burning the composition. Graphite fibers, e.g., at between about 1 and about 10 wt%, may be also be used, either as the sole fibrous material or in conjunction with alumina-containing fibers to perform this reinforcing function.
The invention will now be described in greater detail by way of specific example.
PATENT
Examples 1-8 Gas generant formulations according to the invention and their combustion properties are shown in the table below.
Component levels are in weight percent.
KDL* 42.41 41.11 KNOA** 39.59 38.54 Sr(N03) 2 35.84 34.89 PPC (emulsion)*** 5.00 5.00 KC104 13.57 13.57 A1203 2.00 5.00 6.00 8.00 NH4C104 23.62 22.90 CuO 31.97 30.99 100% 100% 100% 100%
~lOOOpsi 0.696 0.627 0.407 0.398 (in/sec) Combustion Temp. (K) 2000 1954 1772 1756 Moles of gas per lOOg 1.854 1.789 1.615 1.565 of generant *KDL = potassium dilituric acid (5-nitro barbituric acid) **KNOA = potassium nitroorotic acid ***PCC = poly propylene carbonate PATENT
KDL* 34 3933 09 KNOA** 40.54 39.46 NH4C104 19.1318.41 18.52 18.03 S KC104 13.5713.57 29.94 29.51 CuO 25.9124.93 PPC (emulsion)*** 5.00 5.00 5.00 5.00 A1203 2.00 5.00 6.00 8.00 100% 100% 100% 100%
~lOOOpsi 0.4720.315 0.674 0.577 (in/sec) Combustion Temp. (K) 2013 2000 2000 2001 Moles of gas per lOOg 2.001 1.940 2.343 2.083 of generant *KDL = potassium dilituric acid (5-nitro barbituric acid) **KNOA = potassium nitroorotic acid ***PCC = poly propylene carbonate
GAS GENERANT COMPOSITIONS WITH ALKALI OXIDE SCAVENGERS
The present invention is directed to gas generant compositions suitable for automotive air bag restraint systems, particularly restraint systems in which the gas generant is encased in aluminum housing and/or generates gases which come into contact with aluminum components, such as filters.
Background of the Invention:
Most automotive air bag restraint systems, presently in use, use gas generant compositions in which sodium azide is the principal fuel. Because of disadvantages with sodium azide, particularly instability in the presence of metallic impurities and toxicity, which presents a disposal problem for unfired gas generators, there is a desire to develop non-azide gas generant systems and a number of non-azide formulations have been proposed. However, to date, non-azide gas generants have not made significant commercial inroads.
U.S. Patent No. 5,015,309 to Wardle et al., the teachings of which are incorporated herein by reference, teaches gas generant compositions in which fuels are salts of 5-nitrobarbituric acid, salts of 5-nitroorotic acid and nitrouracil (which doesn't form a salt), oxidizers include alkali (except sodium) and alkaline earth metal salts of nitrates, nitrites and hexanitrocolbatate, and binders, when needed for pelletization.
This patent teaches that minimal amounts of non-gas generating components should be added, except up to 1 wt% fibers, such as graphite or iron fibers, which increase the burning rate and transfer heat during combustion.
, PATENT
The 5,015,309 patent teaches that the compositions are useful for inflators as taught in U.S. Patent No. 4,547,342 to Adams et al., the teachings of which are incorporated herein by reference. The inflators taught in U.S. Patent No. 4,547,342 have aluminum housings and other aluminum components. A
disadvantage with compositions such as taught in the 5,015,309 patent is that combustion products include K2O which is highly corrosive to aluminum. Improved formulations are needed to reduce degradation of aluminum components during combustion of the gas generant composition. Also, it is highly desirable that the combustion products include a slag which is filterable. The compositions taught in the 5,015,309 patent are not filterable.
Summary of the Invention:
A gas generant composition using as the fuel component a compound selected from 5-nitrobarbituric acid, 5-nitroorotic acid, alkali and alkaline earth metal salts thereof; an oxidizer for the fuel selected from ammonium, alkali metal and alkaline earth metal salts of chlorates, perchlorates and nitrates and transition metal oxides; and a binder, also contains alumina (Al2O3) and/or silica (SiO2) as a scavenger of alkali metal oxides.
Detailed Description of Certain Preferred Embodiments:
The fuel comprises between about 20 and about 55 wt% of the gas generant composition. Preferred fuels are the potassium salts of 5-nitrobarbituric acid (also called dilituric acid) and 5-nitroorotic acid.
The oxidizer, which is used at a level of between about 50 and about 75 wt% is selected from ammonium, alkali metal and alkaline earth metal chlorates, perchlorates, nitrates, transition metal oxides, and mixture thereof.
Optionally, a portion of the oxidizer may be a transition PATENT
metal oxide, such as cupric oxide. Such a transition metal oxide preferably comprises between about 5 to about 35 wt~ of the composition. In addition to their oxidizing function, these oxides provide hard particles, facilitating compaction of the composition into pellets or other consolidated solid shapes.
As is taught in U.S. Patent No. 5,139,588, the teachings of which are incorporated herein by reference, the cations of the fuel salts and oxidizers are preferably mixture of alkali metal cations, i.e., lithium, sodium and potassium, and alkaline earth metal cations, i.e., magnesium, strontium, barium and cerium. Upon combustion, the alkali cations form liquid combustion products and the alkaline earth metal cations form solid combustion products, the mixture of liquid and solid combustion products forming clinkers which can be readily removed from the gas stream by filtration. The ratio of solid to liquid combustion products may be adjusted by the ratio of alkaline earth metal cations to alkali metal cations.
Of alkali metal cations, sodium is preferred over potassium as sodium oxide is more readily scavenged by alumina or silica than potassium oxide.
In accordance with the present invention, alumina, silica or mixtures thereof are added to scavenge corrosive alkali metal oxides, such as sodium oxide and potassium oxide. Accordingly, the composition of the present invention contains alumina and/or silica at a level of between about 0.5 and about 10 wt%, preferably between about 1 and about 8 wt%. The alumina and/or silica may be in the form of particulates or as fibers, such as fibers of various silica/alumina content. Alumina is generally preferred over silica, being a more efficient scavenger.
A binder is added at a level of between about 1 and about 5 wt%. Suitable binder materials include but are not limited to molybdenum disulfide, graphite, polytetrafluroethylene, VitonR (a copolymer of vinylidene fluoride and hexafluoropropylene), PATENT
nitrocellulose, polysaccharides, polyvinylpyrrolidones, polycarbonates, sodium silicate, calcium stearate, magnesium stearate and mixtures thereof. Preferred binder materials are molybdenum disulfite and polycarbonates.
Alkali metal and alkaline earth metal carbonates and/or oxalates may optionally be added up to about 40 wt%. These act as coolants, lowering the combustion temperature. Lower combustion temperatures minimize production of toxic gases, such as CO and NOx. Generally, if used, these coolants are used at a lo level of at least about 1 wt%.
As noted above, the alumina and/or silica may be in the form of fibers. Fibers help to mechanically reinforce the consolidated unburned material and subsequently consolidate slag material formed by burning the composition. Graphite fibers, e.g., at between about 1 and about 10 wt%, may be also be used, either as the sole fibrous material or in conjunction with alumina-containing fibers to perform this reinforcing function.
The invention will now be described in greater detail by way of specific example.
PATENT
Examples 1-8 Gas generant formulations according to the invention and their combustion properties are shown in the table below.
Component levels are in weight percent.
KDL* 42.41 41.11 KNOA** 39.59 38.54 Sr(N03) 2 35.84 34.89 PPC (emulsion)*** 5.00 5.00 KC104 13.57 13.57 A1203 2.00 5.00 6.00 8.00 NH4C104 23.62 22.90 CuO 31.97 30.99 100% 100% 100% 100%
~lOOOpsi 0.696 0.627 0.407 0.398 (in/sec) Combustion Temp. (K) 2000 1954 1772 1756 Moles of gas per lOOg 1.854 1.789 1.615 1.565 of generant *KDL = potassium dilituric acid (5-nitro barbituric acid) **KNOA = potassium nitroorotic acid ***PCC = poly propylene carbonate PATENT
KDL* 34 3933 09 KNOA** 40.54 39.46 NH4C104 19.1318.41 18.52 18.03 S KC104 13.5713.57 29.94 29.51 CuO 25.9124.93 PPC (emulsion)*** 5.00 5.00 5.00 5.00 A1203 2.00 5.00 6.00 8.00 100% 100% 100% 100%
~lOOOpsi 0.4720.315 0.674 0.577 (in/sec) Combustion Temp. (K) 2013 2000 2000 2001 Moles of gas per lOOg 2.001 1.940 2.343 2.083 of generant *KDL = potassium dilituric acid (5-nitro barbituric acid) **KNOA = potassium nitroorotic acid ***PCC = poly propylene carbonate
Claims (7)
1. A gas generant composition comprising between about 5 and about 55 wt% of a fuel which is selected from the group consisting of 5-nitrobarbituric acid, 5-nitroorotic acid, alkali and/or alkaline earth metal salts of the 5-nitrobarbituric acid or 5-nitroorotic acid, and mixtures thereof, between about 30 and about 75 wt% of an oxidizer selected from the group consisting of ammonium, alkali metal and alkaline earth metal chlorates, perchlorates, nitrates, transition metal ocides, and mixtures thereof, between about 0.5 and about 10 wt% alumina and/or silica, and between about 1 and about 5 wt% of a binder.
2. A generant composition according to claim 1 wherein said binder is selected from the group consisting of molybdenum disulfite, graphite, polytetrafluoroethylene, vinyl fluoride/hexafluoropropylene copolymer, nitrocellulose, polysaccharides, polyvinylpyrrolidones, polycarbonates, sodium silicate, calcium stearate, magnesium stearate and mixtures thereof.
3. A gas generant according to claim 1 wherein said binder is selected from the group consisting of molybdenum disulfide and polycarbonates.
4. A gas generant composition according to claim 1 comprising between about 5 and about 35 wt% of a transition metal oxide.
5. A gas generant composition according to claim 4 wherein said transition metal oxide is cupric oxide.
6. A gas generant composition according to claim 1 further containing between about 1 and about 40 wt% of a coolant selected from the group consisting of alkali metal and alkaline earth metal carbonates, oxalates and mixtures thereof.
7. A gas generant composition according to Claim 1 further containing between about 1 and about 10 wt% of graphite fibers.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US22898394A | 1994-04-18 | 1994-04-18 | |
| US08/228,983 | 1994-04-18 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2143360A1 true CA2143360A1 (en) | 1995-10-19 |
Family
ID=22859343
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002143360A Abandoned CA2143360A1 (en) | 1994-04-18 | 1995-02-24 | Gas generant compositions with alkali oxide scavengers |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0678492A1 (en) |
| JP (1) | JPH0834693A (en) |
| KR (1) | KR950029072A (en) |
| AU (1) | AU1342695A (en) |
| CA (1) | CA2143360A1 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19541924A1 (en) * | 1995-11-10 | 1997-05-15 | Diehl Gmbh & Co | Two stage gas generator for vehicle occupant safety airbag |
| CN100417631C (en) * | 2005-07-29 | 2008-09-10 | 比亚迪股份有限公司 | Safety gas pocket gas production medicine and its preparation method |
| DK2366457T3 (en) * | 2010-03-19 | 2013-06-10 | Alfa Laval Corp Ab | DEVICE AND PROCEDURE FOR MONITORING AND ADJUSTING A RADIAL POSITION OF A INTERFACE LAYER IN A CENTRIFUGE |
| WO2016097826A1 (en) * | 2014-12-19 | 2016-06-23 | Tubitak | O -chlorobenzylidene malononitrile (cs) based self-combustible pyrotechnic compositions which have low ignition temperatures |
| CN112570025B (en) * | 2020-10-30 | 2023-04-21 | 中北大学 | Barbituric acid modified polyoxometalate hybrid and preparation method thereof |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3862866A (en) * | 1971-08-02 | 1975-01-28 | Specialty Products Dev Corp | Gas generator composition and method |
| US4321924A (en) * | 1980-05-12 | 1982-03-30 | The Procter & Gamble Company | Bordered disposable absorbent article |
| US4547342A (en) * | 1984-04-02 | 1985-10-15 | Morton Thiokol, Inc. | Light weight welded aluminum inflator |
| US4948439A (en) * | 1988-12-02 | 1990-08-14 | Automotive Systems Laboratory, Inc. | Composition and process for inflating a safety crash bag |
| US5015309A (en) * | 1989-05-04 | 1991-05-14 | Morton International, Inc. | Gas generant compositions containing salts of 5-nitrobarbituric acid, salts of nitroorotic acid, or 5-nitrouracil |
| US5139588A (en) * | 1990-10-23 | 1992-08-18 | Automotive Systems Laboratory, Inc. | Composition for controlling oxides of nitrogen |
| US5160386A (en) * | 1991-11-04 | 1992-11-03 | Morton International, Inc. | Gas generant formulations containing poly(nitrito) metal complexes as oxidants and method |
| JPH0680491A (en) * | 1992-04-01 | 1994-03-22 | Asahi Chem Ind Co Ltd | Gas generator for airbag |
-
1995
- 1995-02-23 AU AU13426/95A patent/AU1342695A/en not_active Abandoned
- 1995-02-24 CA CA002143360A patent/CA2143360A1/en not_active Abandoned
- 1995-03-14 EP EP95301693A patent/EP0678492A1/en not_active Withdrawn
- 1995-03-15 JP JP7055878A patent/JPH0834693A/en active Pending
- 1995-04-14 KR KR1019950008749A patent/KR950029072A/en not_active Application Discontinuation
Also Published As
| Publication number | Publication date |
|---|---|
| KR950029072A (en) | 1995-11-22 |
| AU1342695A (en) | 1995-11-16 |
| EP0678492A1 (en) | 1995-10-25 |
| JPH0834693A (en) | 1996-02-06 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP0661253B1 (en) | Gas generant compositions using dicyanamide salts as fuel | |
| CA2134189C (en) | Gas generant composition for use with aluminum components | |
| KR100357040B1 (en) | Non-azide gas generating composition having heat absorbing additive | |
| EP0509763B1 (en) | Method of controlling the amount of oxides of nitrogen in generated gas for airbags | |
| RU2127715C1 (en) | Non-azide gas forming composition with operating catalyst | |
| EP0482852B1 (en) | Azide-free gas generant composition with easily filterable combustion products | |
| AU747904B2 (en) | Pyrotechnic mixtures generating non-toxic gases based on ammonium perchlorate | |
| US5467715A (en) | Gas generant compositions | |
| US5989367A (en) | Particle-free, gas-producing mixture | |
| US6149745A (en) | Gas generant composition | |
| KR19990082100A (en) | Non-Zide Gas Generating Compositions | |
| US5472535A (en) | Gas generant compositions containing stabilizer | |
| JP3157501B2 (en) | Low temperature combustion gas generating composition | |
| US5629494A (en) | Hydrogen-less, non-azide gas generants | |
| CA2143360A1 (en) | Gas generant compositions with alkali oxide scavengers | |
| KR20000076253A (en) | Air bag gas-generating composition with only a small amount of residue | |
| AU663659B2 (en) | Mixed fuel gas generant compositions | |
| KR20010106408A (en) | Gas generator composition |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Dead |