WO2000060154A1 - Method of formulating a gas generant composition - Google Patents
Method of formulating a gas generant composition Download PDFInfo
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- WO2000060154A1 WO2000060154A1 PCT/US2000/009165 US0009165W WO0060154A1 WO 2000060154 A1 WO2000060154 A1 WO 2000060154A1 US 0009165 W US0009165 W US 0009165W WO 0060154 A1 WO0060154 A1 WO 0060154A1
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- WIPO (PCT)
- Prior art keywords
- oxidizer
- gas generant
- compositions
- nitrate
- gas
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C06—EXPLOSIVES; MATCHES
- C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
- C06B25/00—Compositions containing a nitrated organic compound
- C06B25/34—Compositions containing a nitrated organic compound the compound being a nitrated acyclic, alicyclic or heterocyclic amine
-
- 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
- the present invention relates to nontoxic gas generating compositions that when combusted rapidly generate gases that are useful for actuating vehicle occupant restraint systems in motor vehicles and specifically, the invention relates to thermally stable nonazide gas generants having not only acceptable burn rates and sustained combustion, but also a relatively high gas volume to solid particulate ratio at acceptable flame temperatures.
- pyrotechnic nonazide gas generants In addition to a fuel constituent, pyrotechnic nonazide gas generants often contain ingredients such as an oxidizer to provide the required oxygen for rapid combustion and reduce the quantity of toxic gases generated, a catalyst to promote the conversion of toxic oxides of carbon and nitrogen to innocuous gases, and a slag forming constituent to cause the solid and liquid products formed during and immediately after combustion to agglomerate into filterable clinker-like particulates. Other optional additives, such as burning rate enhancers or ballistic modifiers and ignition aids, are used to control the ignitability and combustion properties of the gas generant.
- nonazide gas generant compositions One of the disadvantages of known nonazide gas generant compositions is the amount and physical nature of the solid residues formed during combustion. The solids produced as a result of combustion must be filtered and otherwise kept away from contact with the occupants of the vehicle. It is therefore highly desirable to develop compositions that produce a minimum of solid particulates while still providing sufficient quantities of a nontoxic gas to inflate the safety device at an acceptable rate.
- phase stabilized ammonium nitrate is desirable because it generates abundant nontoxic gases and minimal solids upon combustion.
- gas generants for automotive applications must be thermally stable.
- gas generant compositions incorporating phase stabilized or pure ammonium nitrate exhibit poor thermal stability, and produce unacceptably high levels of toxic gases, CO and NO x for example, depending on the composition of the associated additives such as plasticizers and binders.
- ammonium nitrate contributes to poor ignitability, lower burn rates, and performance variability.
- gas generant compositions incorporating ammonium nitrate utilize well-known ignition aids such as BKNO 3 to solve this problem.
- an ignition aid such as BKNO 3 is undesirable because it is a highly sensitive and energetic compound, and furthermore, contributes to thermal instability and an increase in the amount of solids produced.
- Certain gas generant compositions comprised of ammonium nitrate are thermally stable, but have burn rates less than desirable for use in gas inflators.
- gas generant compositions generally require a burn rate of at least .4 inch/second (ips) or more at 1000 psi.
- ips .4 inch/second
- Gas generants with burn rates of less than 0.40 ips at 1000 psi do not ignite reliably and often result in "no-fires" in the inflator.
- compositions described in U.S. Patent No. 5,035,757 to Poole exemplify state of the art gas generant compositions that function well but produce relatively large amounts of solid combustion products. As a result, the gas produced is less than that produced by current state of the art "smokeless" gas generants. Thus, more gas generant and greater filtering requirements are required to facilitate operation of an airbag inflator.
- compositions described in U.S. Patent No. 5,872,329 to Burns et al. exemplify current state of the art "smokeless" gas generants.
- the combustion products are primarily gas with minimal formation of solids.
- the benefits include a reduction in the amount of gas generant required and reduced filtering requirements.
- certain compositions described by Burns may be disadvantaged by lower burn rates and a failure to sustain gas generant combustion.
- a stronger and more robust inflator is often required to increase the operating pressure of the inflator and thereby improve the burn of the gas generant.
- the present invention generally relates to gas generant compositions useful in actuating a vehicle occupant restraint system in the event of a motor vehicle accident.
- Application within a vehicle occupant restraint system includes actuation of a seatbelt pretensioner and/or inflation of an airbag.
- Other applications requiring gas generation are also contemplated, including fire suppression systems aboard aircraft and inflators for flotational devices, for example.
- compositions containing 5-aminotetrazole nitrate (5ATN) as a fuel at about 25-100% by weight of the total composition are reconciled by compositions containing 5-aminotetrazole nitrate (5ATN) as a fuel at about 25-100% by weight of the total composition.
- An oxidizer is selected from a group of compounds including phase stabilized ammonium nitrate, ammonium nitrate, potassium nitrate, strontium nitrate, copper dioxide, and basic copper nitrate.
- Other oxidizers well known in the art are also contemplated. These generally include but are not limited to inorganic oxidizers such as alkali and alkaline earth metal nitrates, nitrites, chlorates, chlorites, perchlorates, and oxides.
- Standard binders, slag formers, and coolants may also be incorporated if desired.
- a composition in accordance with the present invention contains by weight 25-95% 5ATN and 5-75% of an oxidizer.
- a more preferred composition consists of 55-85% 5ATN and 20-45% PSAN.
- a method of formulating compositions of the present invention includes providing an excess amount of nitric acid (preferably 1 5.9 or less and preferably chilled at 0-20°C), and then, in the appropriate amounts, adding a nitratable fuel such as 5-aminotetrazole and at least one oxidizer to the nitric acid. The slurry is stirred until a damp or wet paste forms. The paste is then formed into the desired shapes and dried.
- Fig. 1 illustrates the burn rate of state of the art "smokeless” gas generants as compared to a preferred embodiment of the present invention.
- Fig. 2 illustrates the 60L tank pressure and chamber pressure resulting from combustion of state of the art "smokeless" gas generants and a preferred embodiment of the present invention.
- Fig. 3 illustrates a comparison of pressure vs. time in a 40cc tank with respect to state of the art compositions, preferred embodiments of the present invention and control compositions.
- Fig. 4 illustrates the melting point and decomposition temperatures of a preferred embodiment of the present invention, as well as related data separately comparing the respective constituents of the preferred embodiment.
- Fig. 5 illustrates the autoignition temperature of a preferred embodiment of the present invention.
- Fig. 6 illustrates the infrared scans of 5-AT, AN, KN, and the 5-AT»HNO 3 /PSAN10 mixture.
- 5-aminotetrazole nitrate is provided at 25-100% by weight of the gas generant, depending on the application.
- 5-ATN is characterized as an oxygen-rich fuel attributed to the oxygen in the nitrate group.
- the use of 5-ATN within a gas generant composition therefore requires little or no additional oxidizer, again depending on the application.
- 5-ATN is more preferably provided at 30-95% by weight and most preferably provided at 55-85% by weight of the gas generant composition.
- the oxygen balance must be tailored to accommodate reduced levels of carbon monoxide (CO) and nitrogen oxides (NOx) as driven by original equipment manufacturer toxicity requirements.
- CO carbon monoxide
- NOx nitrogen oxides
- the gas generated upon combustion of a gas generant within a vehicle occupant restraint system must minimize or eliminate production of these toxic gases. Therefore, when adding an oxidizer to 5-ATN, it is generally understood that an oxygen balance of about -4.0 to + 4.0 is desirable when the gas generant is used in an airbag inflator. The preferred percentages of 5-ATN reflect this characteristic.
- One or more oxidizers may be selected from the group including nonmetal, alkali metal, and alkaline earth metal nitrates, nitrites, perchlorates, chlorates, and chlorites for example.
- Other oxidizers well known in the art may also be used. These include alkali, alkaline earth, and transitional metal oxides, for example.
- Preferred oxidizers include phase stabilized ammonium nitrate (PSAN), ammonium nitrate, potassium nitrate, and strontium nitrate.
- the oxidizer(s) is provided at 5-70% by weight of the gas generant composition and more preferably at 20-45% by weight of the oxidizer.
- Standard additives such as binders, slag formers, burn rate modifiers, and coolants may also be incorporated if desired.
- Inert components may be included and are selected from the group containing clay, silicon, silicates, diatomaceous earth, and oxides such as glass, silica, alumina, and titania.
- the silicates include but are not limited to silicates having layered structures such as talc and the aluminum silicates of clay and mica; aluminosilicate; borosilicates; and other silicates such as sodium silicate and potassium silicate.
- the inert component is present at about 0.1 -20% by weight, more preferably at about 0.1 -8%, and most preferably at 0.1 -3%.
- a most preferred embodiment contains 73.1 2% 5-ATN and 26.88% PSAN10 (ammonium nitrate stabilized with 10% potassium nitrate).
- the invention is further exemplified by the following examples.
- 5ATN was prepared according to the following method. In an ice bath, 20g (0.235 moles) of anhydrous 5-aminotetrazole and 22 ml (0.350 moles) of concentrated nitric acid were stirred for about one hour. About 70 ml of water was added directly to the slurry, and the entire mixture was heated quickly to boiling. The hot solution was vacuum filtered and allowed to cool at ambient conditions while stirring. The white crystals formed during cooling were vacuum filtered and washed with cold water, then forced through a No. 14 mesh screen to form granules. The wet material was dried for one hour at ambient conditions and formed well-flowing granules.
- the 5ATN dried at ambient conditions contained about 1 .0 wt% water. As tested on a BOE impact apparatus, this material showed no positive fires up to 25 inches (equivalent to about 231 kp.cm).
- Example 1 The 5ATN granules prepared in Example 1 were dried at 105 degrees Celsius for 4 hours to remove any remaining moisture. Elemental analysis for C, H, and N showed by weight 8.36% carbon, 2.71 % hydrogen, and 56.71 % nitrogen. The theoretical values by weight are 8.1 1 % C, 2.72% H, 56.75% N, and 32.41 % O.
- this material showed positive fires at about 4 inches (equivalent to about 37 kp.cm). This demonstrates how 5ATN experiences an increase in impact sensitivity when completely dry.
- the dried 5ATN was tested using a DSC at a heating rate of 10 degrees Celsius per minute.
- the 5ATN melted at 1 56.8 degrees Celsius and then decomposed exothermically with an onset of 1 77.2 degrees Celsius and a peak of 1 82.5 degrees Celsius.
- the 5ATN was also tested using a TGA at a heating rate of 10 degrees Celsius per minute and found to have an 89.3 wt.% gas conversion up to 450 degrees Celsius, with a 67.5 wt.% gas conversion up to about 1 94 degrees Celsius.
- the DSC and TGA data show that the 5ATN autoignites at about 1 80 degrees Celsius with a large release of energy.
- Example 2 The wet 5ATN granules as prepared in Example 1 were compression molded in a 0.5 inch die under a 10-ton force to a height of about 0.1 inches. About half of the pellets were dried for 4 hours at 70 degrees Celsius to remove all the moisture. A weight loss of about 1 .0wt.% confirmed that all of the moisture had been removed.
- Both the wet and dry 5ATN pellets were tested as a booster material using the following specifications. Each pellet was broken into four pieces and the fragments were loaded into a small aluminum cup. This aluminum cup was then crimped to a standard air bag initiator that contained 1 10mg of zinc potassium perchlorate (ZPP). The entire assembly, known as an igniter, was fired inside a closed bomb with a volume of 40 cubic centimeters. The 40 cubic centimeter bomb was equipped with a pressure transducer to measure the pressure rise over time.
- ZPP zinc potassium perchlorate
- Figure 3 shows the results of the tests. Other control tests were done as a comparison to the igniters containing 5ATN.
- Tests 7 and 8 (initiator) are igniters consisting of an empty aluminum cup crimped to an initiator.
- Tests 9 and 10 are control igniters containing both an autoignition material and 8 pellets of a standard nonazide composition as described in U.S. Patent No. 5,035,757.
- Test 1 1 is another control igniter similar to tests 9 and 10, except with autoignition material and 14 pellets of the same nonazide composition.
- Test 1 2 is an igniter containing about 0.7g of undried 5ATN pellet fragments
- Test 1 3 is an igniter containing about 1 .0g of undried 5ATN pellet fragments.
- a composition was prepared containing 77.77 wt.% 5ATN and 22.23 wt.% strontium nitrate.
- the 5ATN as prepared in Example 1 and dried strontium nitrate were combined to form an overall mass of 0.71 g and then mixed and ground with a mortar and pestle.
- the composition was tested by DSC at a heating rate of 5 degrees Celsius per minute and found to melt at 1 55.3 degrees Celsius and then decomposed with a large exotherm (175.6 degrees Celsius onset, 179.4 degrees Celsius peak).
- composition was tested by TGA at a heating rate of 10 degrees Celsius per minute and found to have a 91 .7 wt.% gas conversion up to 950 degrees Celsius, with a 74.1 wt.% gas conversion up to about 1 96 degrees Celsius. As tested on a BOE impact apparatus, this composition showed positive fires at about 3 inches (equivalent to about 28 kp.cm). This composition burned vigorously when ignited with a propane torch.
- a composition was prepared containing 65.05wt.% 5ATN and 34.95 wt.% copper (II) oxide.
- the 5ATN as prepared in Example 1 and the dried copper oxide were combined to form an overall mass of 0.52g and then mixed and ground with a mortar and pestle.
- the composition was tested by DSC at a heating rate of 10 degrees Celsius per minute and found to decompose with a large exotherm peaking at about 1 75 degrees Celsius.
- the composition was tested by TGA at a heating rate of 10 degrees Celsius per minute and found to have an 83.4 wt.% gas conversion up to 400 degrees Celsius, with an 80.6 wt.% gas conversion up to about 1 83 degrees Celsius.
- this composition showed positive fires at about 3 inches (equivalent to about 28 kp.cm). This composition burned vigorously when ignited with a propane torch.
- a composition was prepared containing 65.05wt.% 5ATN and 34.95 wt.% copper (II) oxide.
- the 5ATN as prepared in Example 1 and the dried copper oxide were combined to form an overall mass of 1 .00g.
- Enough water was added to form a slurry and then the components were mixed and ground with a mortar and pestle. The water was allowed to evaporate by holding the mixture at 70 degrees Celsius. Eventually, a sticky, polymer-like substance formed which became very hard with complete drying.
- the composition was tested by DSC at a heating rate of 10 degrees Celsius per minute and found to exhibit multiple exotherms beginning at about 1 37 degrees Celsius. This composition burned vigorously when ignited with a propane torch.
- This example demonstrates how 5ATN can be combined with a common oxidizer through either dry or wet mixing.
- a composition was prepared containing 67.01 wt.% 5ATN and 32.99 wt.% PSAN10 (AN phase stabilized with 10wt.% KN).
- the 5ATN as prepared in Example 1 and the dried PSAN 10 were combined to form an overall mass of 0.24g and then mixed and ground with a mortar and pestle.
- Figure 5 shows a melting point of 132°C and a decomposition point of 1 53°C. See curve 1 7.
- the various constituents are also analyzed separately. See curves 14-1 6.
- Fig. 1 illustrates, gas generants of the present invention as exemplified by curve 1 , have acceptable burn rates at ambient pressures and above, and have significantly higher burn rates as compared to state of the art "smokeless" gas generants (curve 2).
- Curve 1 indicates a gas generant containing 73.1 2% 5-ATN and 26.88% phase stabilized ammonium nitrate (stabilized with 10% potassium nitrate).
- Curve 2 is a comparison of a gas generant containing 65.44% phase stabilized ammonium nitrate (stabilized with 10% potassium nitrate or PSAN10), 25.80% of the diammonium salt of 5,5'-Bi-
- Fig. 3 illustrates a comparison between a preferred embodiment containing the same fuel as curve 1 in Example 8. See curves 3 and 4. Curves 5 and 6 correspond to the same "smokeless" gas generant as indicated in curve
- the burn rate was measured by igniting a compressed slug in a closed bomb at a constant pressure of 1000 psi.
- the ignitability of the formulations was determined by attempting to ignite the samples at ambient pressure with a propane torch.
- the outputs of the subjective analysis are the following: the time it takes for the sample to reach self-sustaining combustion after the torch flame touches the sample, and the ease of which the sample continues combustion when the torch flame is removed.
- Formulation 1 was 73.1 2% 5-ATN and 26.89% PSAN10. The sample ignited instantly when touched with the flame from a propane torch and continued to burn vigorously when the flame was removed. The burn rate of this formulation at 1000 psi was measured to 0.69 inches per second (ips). To minimize the production of either CO or NOx, this composition was formulated to have an oxygen balance of -2.0 wt.% oxygen.
- Formulation 2 was 62.21 % azobisformamidine dinitrate and 37.79% PSAN10. When contacted with the flame from a propane torch, the sample did not ignite for a few seconds. After it appeared that self-sustaining combustion had begun, the torch was removed and the sample extinguished. After igniting the sample a second time, it burned slowly to completion. The burn rate of this formulation at 1000 psi was measured at 0.47 ips. To minimize the production of either CO or NOx, this composition was formulated to have an oxygen balance of 0.0 wt.% oxygen.
- the base 5-AT fuel has more energy (positive heat of formation) than the base azobisformamidine fuel (negative heat of formation).
- the nitrated 5-AT has a higher oxygen content and therefore allows for the use of a lesser amount of the PSAN oxidizer. It is well known that the higher levels of PSAN will negatively affect the ignitability and burn rate of many propellant compositions.
- Table 1 illustrates the problem of thermal instability when typical nonazide fuels are combined with PSAN:
- Example 1 1 “decomposed” indicates that pellets of the given formulation were discolored, expanded, fractured, and/or stuck together (indicating melting), making them unsuitable for use in an air bag inflator.
- any PSAN-nonazide fuel mixture with a melting point of less than 1 1 5C will decompose when aged at 107C.
- many compositions that comprise well-known nonazide fuels and PSAN are not fit for use within an inflator due to poor thermal stability.
- the melting point of a preferred embodiment is greater than 1 1 5C (1 32C), thereby indicating that combining 5-ATN with PSAN does not significantly affect the stability of the propellant.
- nitrocellulose a standard gas generant for seat belt pretensioners. Gas yield, gas conversion, autoignition temperature, solids production, combustion temperatures, and density were roughly equivalent. Seat belt retractor tests also revealed fairly equivalent performance results. The following data was developed relative to nitrocellulose:
- the preferred embodiment resulted in combustion gases containing 0.0% CO and 2.4% hydrogen, and 97.6% preferred gases containing nitrogen, carbon dioxide, and water.
- nitrocellulose resulted in combustion gases containing 29.2% CO and 1 9.7% hydrogen, and 51 .1 % preferred gases containing nitrogen, carbon dioxide, and water.
- compositions of the present invention provide similar performance to nitrocellulose but with improved thermal stability, impact sensitivity, and content of effluent gases when used as a pretensioner gas generant.
- compositions containing 100% 5-ATN were used as pretensioner gas generants despite exhibiting an oxygen balance of -10.80 wt.% oxygen.
- the amount of gas generant used in a pretensioner is small enough (roughly one gram) to permit an excessive negative oxygen balance without prohibitive levels of CO.
- compositions of the present invention include gas generants exhibiting oxygen balances in the range of -1 1 .0 to + 1 1 .0.
- the oxygen balance may be readily determined by well known theoretical calculations.
- An oxygen balance of about + 4.0 to -4.0% is preferred for compositions used in vehicle occupant restraint systems as main gas generants.
- Compositions exhibiting an oxygen balance outside of this range are useful as autoignition compounds or igniter compounds in an inflator; as a pretensioner gas generant; in a fire suppression mechanism; as a gas generant for an inflatable vessel or airplane ramp, or where levels of toxic gases such as CO and NOx are not critical for the desired use.
- the oxygen balance is the weight percent oxygen necessary to result in stoichiometric combustion of the propellant.
- 5-aminotetrazole nitrate has a less negative oxygen balance than typical nonazide fuels and is considered to be self-deflagrating. This allows for compositions with significantly less PSAN (or other oxidizer) which will ignite more readily and combust at lower inflator operating pressures than previously known smokeless gas generants. Essentially, these compositions combine the benefits of the typical high-solids nonazide gas generants as exemplified by U.S. Patent No.
- nitratable base fuels include, but are not limited to nitrourea, 5-aminotetrazole, diaminotriazole, urea, azodicarbonamide, hydrazodicarbonamide, semicarbazide, carbohydrazide, biuret, 3,5-diamino-1 ,2,4-triazole, dicyandiamide, and 3-amino-1 ,2,4-triazole.
- Each of these base fuels may be nitrated and combined with one or more oxidizers.
- gas generant compositions containing 5- ATN and one or more oxidizers as described below but not thereby limited, exemplify the manufacture of gas generant compositions containing any nitrated base fuel and one or more oxidizers.
- the constituents of the gas generant compositions may all be obtained from suppliers well known in the art.
- the base fuel (5AT) and at least one oxidizer are added to excess concentrated nitric acid and stirred until a damp paste forms.
- This paste is then formed into granules by either extrusion or forcing the material through a screen.
- the wet granules are then dried. It has been found that the process not only forms a nitrated fuel, but also forms particularly intimate mixtures when the oxidizer is added in solution.
- the crystals formed thus represent homogeneous 5-AT nitrate/oxidizer solid solutions. This is particularly advantageous when homogeneous granules are desired because the probability of inconsistent mixing on the granular level is substantially reduced.
- the granules formed from the solid solution actually represent homogeneous solutions whereas a given granule formed from dry mixing, for example, at times may primarily comprise either the fuel or oxidizer, but not both.
- the performance and burn rate can therefore be disadvantaged.
- the process also comprises a "one-pot" process. For example, if a composition containing 5-AT nitrate and PSAN is desired, then combining 5- AT, ammonium nitrate and potassium nitrate in a concentrated nitric acid solution results in a composition containing 5-AT nitrate and PSAN.
- a composition containing 5-AT nitrate and PSAN is desired, then combining 5- AT, ammonium nitrate and potassium nitrate in a concentrated nitric acid solution results in a composition containing 5-AT nitrate and PSAN.
- two different processes are not required to form both the 5-AT nitrate and the PSAN, and yet a composition enjoying the inherent benefits of both results.
- Related benefits include simplified processing and a reduction in manufacturing costs.
- the nitric acid can be the standard reagent grade (1 5.9M,- 70wt.%HNO 3 ) or can be less concentrated as long as enough nitric acid is present to form the mononitrate salt of 5AT.
- the nitric acid should preferably be chilled to 0-20°C before adding the 5AT and oxidizers to ensure that the 5AT does not decompose in the concentrated slurry. However, shortening the process time will also inhibit the decomposition of 5AT.
- the precise mixing equipment used is not important - it is necessary however to thoroughly mix all the components and evaporate the excess nitric acid. As with any process using acids, the materials of construction must be properly selected to prevent corrosion. In addition to routine safety practices, sufficient ventilation and treatment of the acid vapor is important.
- the paste can be placed in a screw-feed extruder with holes of desired diameter and then chopped into desired lengths.
- An oscillating granulator may also be used to form granules of desired size.
- the material should be kept wet through all the processing steps to minimize safety problems.
- the final granules can be dried in ambient pressure or under vacuum. It is most preferred to dry the material at about 30°C under a -1 2 psig vacuum.
- Example 1 5 illustrates the process.
- This material was then passed through a low-pressure extruder to form long 'noodles' that were consequently chopped to from cylindrical granules. These granules were then placed in a vacuum oven at 30°C and -1 2psig vacuum overnight. After drying, the granules were screened and those that passed through a No. 4 mesh screen but not through a No. 20 mesh screen were retained.
- Example 1 A preferred method of formulating gas generant compositions containing 5-aminotetrazole nitrate and phase stabilized ammonium nitrate is described in Example 1 6.
- One of ordinary skill will readily appreciate that the following description merely illustrates, but does not limit, mixing of the constituents in the exact amounts of ingredients described.
- other oxidizers may be used in lieu of PSAN.
- 1 00 ml of 70 wt.% HNO 3 solution equals 99.4 g (1 .58 mol) HNO 3 plus 42.6 g (2.36 mol) H 2 O.
- the solution is mixed by stirring in 100 g dry 5- aminotetrazole (5-AT) which equals 1 .1 8 mol 5-AT, 58 g dry ammonium nitrate (AN), and 6.5 g potassium nitrate (KN) (10% of total AN + KN).
- the sequence of addition is not critical.
- ammonium nitrate has been used to stabilize the ammonium nitrate, one of ordinary skill will readily appreciate that the ammonium nitrate may also be stabilized with other known stabilizers such as, but not limited to, potassium perchlorate and other potassium salts.
- Granules or pellets are then formed from the paste by methods well known in the art.
- the granules or pellets are then dried to remove any residual HNO 3 and H 2 O.
- the end product consists of dry granules or pellets of a composition containing about 73 wt.% 5-AT* HNO 3 + 27 wt.% PSAN 10.
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Combustion & Propulsion (AREA)
- Air Bags (AREA)
- Automotive Seat Belt Assembly (AREA)
- Feeding, Discharge, Calcimining, Fusing, And Gas-Generation Devices (AREA)
Abstract
Description
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Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
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EP00921784A EP1165871A1 (en) | 1999-04-07 | 2000-04-07 | Method of formulating a gas generant composition |
JP2000609640A JP2002541049A (en) | 1999-04-07 | 2000-04-07 | Method of formulating a gas generating composition |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
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US12810199P | 1999-04-07 | 1999-04-07 | |
US60/128,101 | 1999-04-07 | ||
US13066099P | 1999-04-23 | 1999-04-23 | |
US60/130,660 | 1999-04-23 |
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WO2000060154A1 true WO2000060154A1 (en) | 2000-10-12 |
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PCT/US2000/009165 WO2000060154A1 (en) | 1999-04-07 | 2000-04-07 | Method of formulating a gas generant composition |
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EP (1) | EP1165871A1 (en) |
JP (1) | JP2002541049A (en) |
WO (1) | WO2000060154A1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1678006A2 (en) * | 2003-10-17 | 2006-07-12 | Automotive Systems Laboratory, Inc. | Filterless airbag module |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3457127A (en) * | 1968-03-18 | 1969-07-22 | Melvin Cook | Explosive composition containing an additional product of urea and nitric acid and method of preparing same |
US3898112A (en) * | 1970-09-23 | 1975-08-05 | Us Navy | Solid 5-aminotetrazole nitrate gas generating propellant with block copolymer binder |
US5472647A (en) * | 1993-08-02 | 1995-12-05 | Thiokol Corporation | Method for preparing anhydrous tetrazole gas generant compositions |
US5847315A (en) * | 1996-11-29 | 1998-12-08 | Ecotech | Solid solution vehicle airbag clean gas generator propellant |
-
2000
- 2000-04-07 JP JP2000609640A patent/JP2002541049A/en active Pending
- 2000-04-07 WO PCT/US2000/009165 patent/WO2000060154A1/en not_active Application Discontinuation
- 2000-04-07 EP EP00921784A patent/EP1165871A1/en not_active Withdrawn
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3457127A (en) * | 1968-03-18 | 1969-07-22 | Melvin Cook | Explosive composition containing an additional product of urea and nitric acid and method of preparing same |
US3898112A (en) * | 1970-09-23 | 1975-08-05 | Us Navy | Solid 5-aminotetrazole nitrate gas generating propellant with block copolymer binder |
US5472647A (en) * | 1993-08-02 | 1995-12-05 | Thiokol Corporation | Method for preparing anhydrous tetrazole gas generant compositions |
US5847315A (en) * | 1996-11-29 | 1998-12-08 | Ecotech | Solid solution vehicle airbag clean gas generator propellant |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1678006A2 (en) * | 2003-10-17 | 2006-07-12 | Automotive Systems Laboratory, Inc. | Filterless airbag module |
EP1678006A4 (en) * | 2003-10-17 | 2007-04-04 | Automotive Systems Lab | Filterless airbag module |
Also Published As
Publication number | Publication date |
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EP1165871A1 (en) | 2002-01-02 |
JP2002541049A (en) | 2002-12-03 |
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