EP1000917A1 - Composition génératrice de gaz - Google Patents

Composition génératrice de gaz Download PDF

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Publication number
EP1000917A1
EP1000917A1 EP99122585A EP99122585A EP1000917A1 EP 1000917 A1 EP1000917 A1 EP 1000917A1 EP 99122585 A EP99122585 A EP 99122585A EP 99122585 A EP99122585 A EP 99122585A EP 1000917 A1 EP1000917 A1 EP 1000917A1
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EP
European Patent Office
Prior art keywords
weight
gas
range
nitride
gas producing
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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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Application number
EP99122585A
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German (de)
English (en)
Inventor
Tadamasa c/o Nihon Plast Co. Ltd. Harada
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Nihon Plast Co Ltd
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Nihon Plast Co Ltd
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Publication of EP1000917A1 publication Critical patent/EP1000917A1/fr
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    • 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
    • C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
    • C06B31/00—Compositions containing an inorganic nitrogen-oxygen salt
    • C06B31/28—Compositions containing an inorganic nitrogen-oxygen salt the salt being ammonium nitrate

Definitions

  • the present invention relates to a gas producing composition applied to a gas producing apparatus for an airbag, and more particularly, to a gas producing composition which produces a predetermined gas to be easily handled.
  • metal azide As gas producing agent applied to an airbag, the agent specially containing sodium azide (Na 3 N).
  • Na 3 N sodium azide
  • the sodium azide itself is difficult to handle, and it is popular to conduct a research of gas producing agent which does not use it.
  • gas producing agent of which main component is a mixture of an organic compound containing a lot of amino groups and nitrogen there is gas producing agent for an airbag which main components are ammonium nitrate, amino tetrazole (CH2NH4NH2), and binder ( Japanese Patent Application Laid-Open Publication No. 10-130086 ).
  • the composition is superior in not using metal azide. It can increases gas production amount per unit weight and decreases solid residue to be produced. Weight of a filter components for filteration of the residue are lowered and amount of gas producing agent can be smaller, and a gas producing apparatus can be miniaturized, thus beginning to put the agent into practical use.
  • This composition uses an organic compound, thus containing four chemical elements of carbon, nitrogen, hydrogen, and oxygen naturally.
  • the compound produces gas under high temperatures, undesirable nitric oxide, and/or carbon monoxide are produced.
  • the composition includes oxygen increased to sufficiently oxidize carbon monoxide to be changed to carbon dioxide, excessive oxygen reacts with nitrogen, thus producing nitric oxide.
  • the composition includes oxygen decreased to reduce nitric oxide, there occurs phenomenon that carbon monoxide increases, thus cannot producing neither at the same time.
  • gas environment inside a vehicle needs that of no influence for a human body, but it is very difficult to realize. Further, these gas producing composition produces high temperature gas during actuation of the airbag, so safety measure should be installed to the inflator. This causes an airbag a more complicate structure and factor for cost increase.
  • Another object of the present invention is to prepare gas producing compositions which produce large amount of the gas production per unit weight of the compositions and decrease residue produced from the compositions.
  • a first aspect of the invention provides a gas producing composition including: ammonium nitrate (NH 4 NO 3 ); and metal nitride.
  • the gas producing composition preferably, further includes inorganic oxidizing agent.
  • the gas producing composition preferably, further includes metal powder.
  • the inorganic oxidizing agent is, preferably, inorganic nitrate.
  • the metal nitride preferably, is nitride containing boron (B), silicon (Si), aluminum (Al), or mixture thereof.
  • the ammonium nitrate preferably, is within a range between 10% and 95% by weight, the metal nitride is within a range between 5% and 30% by weight, and the inorganic oxidizing agent is within a range between 0% and 50% by weight.
  • the gas producing composition is adapted for production of a predetermined gas containing an oxygen gas.
  • the inorganic oxidizing agent preferably, is within a range between 1% and 15% by weight and, further preferably, within a range between 3% and 10% by weight. In order to generate the gas which does not contain large amount of the water (less than 25% water) and increase the amount of the gas production per unit weight, following compositions are preferable.
  • ammonium nitrate is, preferably, within a range between 50% and 70% by weight, and the metal nitride is boron nitride within a range between 30% and 50% by weight.
  • ammonium nitrate is, preferably, within a range between 40% and 60% by weight
  • metal nitride is silicon nitride within a range between 25% and 40% by weight and boron nitride within a range between 10% and 15% by weight
  • the inorganic oxidizing agent is potassium nitrate within a range under 20.0% by weight.
  • ammonium nitrate is, preferably, about 50% by weight
  • metal nitrate is silicon nitride within a range between 20% and 30% by weight
  • boron nitride is about 10% by weight
  • the inorganic oxidizing agent is strontium nitrate within a range between 10% and 20% by weight.
  • a second aspect of the invention provides a gas producing composition includes: main agent which contains boron nitride and ammonium nitrate; and one of oxidizing agent, metal nitride, and metal powder which is mixed with the main agent.
  • the gas producing composition is adapted for production of water not more than 25% by weight relative to production of all gas.
  • the compositions of the invention did not produce monoxide at all which had been produced by a conventional gas producing agent. Concentration of nitric oxide decreased to minimum 1/10 and maximum 1/1000 compare to that in the gas produced from existing gas producing agent. Further, it was found that compound of compositions were capable of reducing production of water or producing oxygen. In addition, it was found that gas production per unit weight was equal to or more than twice than that of conventional one.
  • character "-" means the component is not included and “nd” means the component is not detected.
  • Ammonium nitrate applied to the embodiments is not restricted especially.
  • ammonium nitrate for industry, fine crystal granular ammonium nitrate, or phase stabilizing ammonium nitrate containing metal oxide such as potassium nitrate or nickel oxide between 3% and 10% by weight as phase stabilizing agent may be preferable for example.
  • Metal nitride may be boron nitride, aluminum nitride, silicon nitride, strontium nitride, calcium nitride, chromium nitride, titanium nitride, copper nitride, magnesium nitride, or zirconium nitride, for example.
  • boron nitride, aluminum nitride, or silicon nitride may be preferable. It is noted that sodium azide is distinguished from nitride and nitride in the embodiments does not include the metal azide.
  • the mixture ratio may be the ammonium nitrate within a range between 20% and 95% by weight, or, preferably, between 40% and 90% by weight, and the metal nitride within a range between 5% and 80% by weight, or, preferably, between 10% and 60% by weight. If the ammonium nitrate is more than this ranges, production of oxygen increases and gas having tendency to cause a fire is produced. If the ammonium nitrate is less than this ranges, supply amount of oxygen decreases, and metal nitride reduces water, thus producing a lot of hydrogen gas.
  • hydrogen is less toxic for human body, however, produce explosion tendency gas or combustion tendency gas by mixing with air. Explosion gas of three components of oxygen-nitrogen-hydrogen does not explode or burn under not more than 4% of hydrogen. Under more than 4% of hydrogen, it become combustion gas, and, under much more than 4 % of hydrogen, it become "mixture gas" which shows explosion tendency. It is considered that hydrogen amount from gas producing agent may preferably be not more than 6% to 7%, depending on mixing amount of air.
  • ammonium nitrate is basically a main component for gas producing source. It has a role as oxidizing agent and metal nitride is reducing agent, thus oxidation-reduction reaction being made use of. Therefore, there can be added other oxidizing agent not including hydrogen, such as inorganic nitrate or perchlorate including sodium, potassium, or strontium, which generally has oxidizing action. Nitrate may preferably be due to both having a role as oxidizing agent and producing nitrogen. Metal nitrate does not include hydrogen, and is able to control production of water.
  • the inorganic oxidizing agent preferably, is within a range between 1% and 15% by weight or, further preferably, within a range between 3% and 10% by weight. Since the inorganic oxidizing agent tends to produce burned residue and has tendency to deteriorate efficiency of gas production, smaller amount of the agent is better.
  • Metal nitride is applied to reducing agent and more than two kinds of metal nitrides may be mixed with each other to be used. Further, there may be mixed metal powder having reducing action, such as aluminum, magnesium, magnalium (Mg-Al alloy), silicon, or boron. In this case, ammonium nitrate may be contained equal to or more than 10 % or, preferably, 20 %.
  • Metal powder makes combustion temperature higher, thus promoting to decompose metal nitride.
  • Metal powder may be added within a range between 0 % and 10 % or, preferably , between 0 % and 4 %. When exceeding these ranges, the amount of gas production per unit weight tends to decrease, and small amount of it is desirable.
  • ammonium nitrate, metal nitride, oxidizing agent, and reducing tendency metal used for the embodiments are granulated or powdered. After mixing these with each other, the mixture is formed by pressure molding or granulation molding in a predetermined shape, such as a flake-shape, a disc-shape, a tablet, a annular shape, a granule, thus being filled in a gas producing apparatus for an airbag.
  • binder to help forming and adhering, such as water glass, silicon oxide, or very small amount of organic binder.
  • inorganic binder may be preferably selected.
  • catalyst to adjust combustion property such as metal oxide including copper, iron, cobalt, or nickel, or alkali metal perchlorate.
  • a combustion container made of iron which had a content volume of 10 ml and in which 60 through-holes having a diameter of 1.5 mm were opened was prepared on the external peripheral portion of a 20 mm diameter cylinder having a wall thickness of 2 mm and provided with one side bottom as shown in Fig. 1 and an 8-micron thick aluminum foil was placed so as to seal peripheral holes (not shown). About 5 g of the granular product which was exactly weighed was placed on the aluminum foil. A screw for assembling an ignition device was disposed at the opening end of the combustion container.
  • the ignition device (made of iron) was provided with a screw fitting to the combustion container and a convex portion having an inside diameter of 7 mm, a wall thickness of 2 mm and a depth of 17 mm. On the bottom of the convex portion, a through-hole for penetrating a lead wire of a fuse head with lead was provided. The fuse head with a lead wire was disposed in the convex portion. 0.1 g of an ignition charge, as major components, 55% of zirconium and 45% of potassium perchlorate was placed around the fuse head and an aluminum adhesive tape was applied to the opening end. This ignition device was attached to the combustion container using the screw to produce a combustor assembly. A pressure withstanding vessel was produced to attain combustion in the combustor assembly.
  • the cylindrical pressure vessel (made of stainless) has a proof pressure of 50 MPa and a content volume of 1000 ml and provided with a lid which could be secured by a quarter round threaded screw, a threaded hole for fitting up a thermocouple, a gas exhaust pipe with a valve, a threaded hole to which a sensor measuring internal pressure could be set and a terminal which could apply ignition current from the outside of the vessel.
  • the thermocouple was formed of a platinum/platinum alloy (0.05 mm diameter), attached to the lid and connected to a direct current amplifier.
  • a pressure gage was a strain gage type sensor and was connected to a strain gage amplifier.
  • Each output of the direct current amplifier and strain gage amplifier were designed so that recording could be made by connecting it to a recorder which could record the output as a function of time.
  • the combustor assembly was placed in the vessel. After the lead wire of the fuse head was connected to the inside portion of the terminal applying ignition current, the pressure vessel was sealed by rotating the lid by a quarter round. Thereafter, vacuum horse, which is connected to a vacuum pump and argon gas bump, was attached to the end of the gas exhaust pipe with valve. This was also provided with a charge valve enabling argon to be filled vacuum. The valve was opened to create vacuum and argon gas was introduced into up to atomosphere pressure into the pressure vessel, thereby substituting the air to argon in the pressure vessel and thereafter the valve was closed.
  • a gas chromatograph with two packed column was prepared in which one packed column was used to measure nitrogen and oxygen (argon gas could also be measured) by using helium as a carrier gas and another packed column was used to measure hydrogen by using nitrogen as a carrier gas.
  • nitrogen and oxygen argon gas could also be measured
  • helium helium
  • hydrogen nitrogen as a carrier gas
  • Each gas with a standard concentration was introduced to produce a calibration curve or line.
  • a detector tube manufactured by Gastech Co.
  • one end of the lead wire used for applying ignition current was connected to a terminal used for applying ignition current disposed outside the pressure vessel and the other end was connected to a blasting machine. Then, the direct current amplifier, the strain gage amplifier and the recording device were made to work to apply ignition current. Each pressure at two temperature points of 500°C and 90°C was afterwards measured. In each vicinity of these temperatures, temperature cooling rate was so gentle that temperature and pressure were measured with relative accuracy. Also, since the pressure data at 90°C was obtained after almost all water was condensed, it was considered that the remainder was only nitrogen, oxygen, hydrogen and argon which was initially filled and hence the total mol number of these three types of gas was calculated.
  • the gas was supposed to be ideal gas.
  • the pressure data obtained at 500°C water was expected to be in a gas state
  • the gas was supposed to be ideal gas to calculate the total mol number of the mixture gas and a difference between this total mol number and the above total mol number measured at 90°C was defined as the mol number of the water (steam).
  • each measurement of derivative gas by using the detector tube and the concentration of the major gas by using gas chromatography were made. From these results, each weight of the gas components other than water can be calculated. Also, from the mol number of water, its weight was calculated. Thus the ratio (%) by weight of each component can be obtained and each amount of produced gases per unit weight can be calculated.
  • Fig. 2 shows results of two and three component-system containing ammonium nitrate and boron nitride.
  • Two component-system included ammonium nitrate within a range between 50.0% and 95.0% by weight and boron nitride within a range between 5.0% and 50.0% by weight.
  • Three component-system included ammonium nitrate within a range between 15.0% and 70.0% by weight, boron nitride of 25.0% by weight, and potassium nitrate within a range between 5.0% and 60.0% by weight. The two and three component-system obtained good results.
  • Fig. 3 shows the results of compositions in which a combination of silicon nitride and aluminum nitride or boron nitride and further metal powder of Si and Al was used as reducing agent and single ammonium nitrate or mixture oxidizing agent containing ammonium nitrate and potassium nitrate was used as oxidizing agent.
  • Three component-system included ammonium nitrate within a range between 50.0% and 70.0% by weight, silicon nitride within a range between 15.0% and 40.0% by weight, and metal nitride (AlN or BN) within a range between 5.0% and 15.0% by weight.
  • Four component-system included ammonium nitrate within a range between 20.0% and 65.0% by weight, silicon nitride within a range between 20.0% and 33.0% by weight, potassium nitrate within a range under 40.0% by weight, and metal powder or metal nitride within a range between 4.0% and 15.0% by weight. Both of the three and four component-system compounds obtained good result.
  • Fig. 4 shows results of compositions in which a combination of silicon nitride and boron nitride or a metal powder of Al and B was used as a reducing agent and mixture of ammonium nitrate and strontium nitrate was used as oxidizing agent.
  • Four component-system included ammonium nitrate within a range between 45.0% and 65.0% by weight, silicon nitride within a range between 20.0% and 31.0% by weight, strontium nitrate within a range between 10.0% and 20.0% by weight, and metal powder or metal nitride within a range between 3.0% and 10.0% by weight.
  • the four component-system compounds obtained good result.
  • Fig. 5 shows results of compositions in which aluminum nitride, single ammonium nitrate, or mixture oxidizing agent of ammonium nitrate and potassium nitrate was used.
  • Two component-system included ammonium nitrate within a range between 70.0% and 90.0% by weight, and aluminum nitride within a range between 10.0% and 30.0% by weight.
  • Three component-system included ammonium nitrate within a range between 60.0% and 70.0% by weight, aluminum nitride within a range between 10.0% and 20.0% by weight, and potassium nitrate of 20.0% by weight. Both of the three and four component-system obtained good results.
  • the "Solid" in Figs. 2 to 5 is a solid substance left after the gas producing-agent is completely burned.
  • compounds preferably have compositions including ammonium nitrate within a range between 15.0% and 95.0% by weight, boron nitride within a range between 5.0% and 25.0% by weight, and potassium nitrate within a range under 60.0% by weight.
  • compositions (No.1 to No.4, No.37, No.39 to No.41, No.68 and No.70) to produce small amount of water which is desired level to keep clean and safety of the crew when an airbag actuates and the amount of the produced gas per unit weight was greater than those of conventional product were found, whereby the problem was solved. That is, compositions including ammonium nitrate within a range between 50.0% and 70.0% by weight, and boron nitride within a range between 30.0% and 50.0% by weight (No.1 to No.4).
  • Compositions are including ammonium nitrate within a range between 40.0% and 60.0% by weight, silicon nitride within a range between 25.0% and 40.0% by weight, potassium nitrate within a range under 20.0% by weight, and boron nitride within a range between 10.0% and 15.0% by weight (No.37 and No. 39 to NO. 41).
  • Compositions are including about 50% by weight of ammonium nitrate, silicon nitride within a range between 20.0% and 30.0% by weight, strontium nitrate within a range between 10.0% and 20.0% by weight, and about 10% by weight of boron nitride (NO.68 and No.70).
  • h1 is a compound according to Japanese Patent Application Laid-Open No. 6-239683. It is to be noted that the amount of the produced gas is a theoretical value in a formulation according to a stoichiometrically ratio.
  • Comparative Example, h2 is a compound according to Japanese Patent Application Laid-Open No. 10-130086, Example 1.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Combustion & Propulsion (AREA)
  • Air Bags (AREA)
  • Feeding, Discharge, Calcimining, Fusing, And Gas-Generation Devices (AREA)
EP99122585A 1998-11-13 1999-11-12 Composition génératrice de gaz Withdrawn EP1000917A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP32371898 1998-11-13
JP10323718A JP2000154087A (ja) 1998-11-13 1998-11-13 ガス発生組成物

Publications (1)

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EP1000917A1 true EP1000917A1 (fr) 2000-05-17

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1074533A1 (fr) * 1999-08-06 2001-02-07 Nihon Plast Co., Ltd. Agent générateur de gaz

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3733177C1 (de) * 1987-10-01 1989-05-11 Bayern Chemie Gmbh Flugchemie Gaserzeugende Masse
JPH06239683A (ja) 1993-02-15 1994-08-30 Daicel Chem Ind Ltd エアバッグ用ガス発生剤
WO1995018780A1 (fr) * 1994-01-10 1995-07-13 Thiokol Corporation Compositions contenant des sels de dicyanamide generant des gaz non acides
US5557062A (en) * 1994-12-13 1996-09-17 United Technologies Corporation Breathable gas generators
JPH10130086A (ja) 1996-10-23 1998-05-19 Nippon Kayaku Co Ltd エアバッグ用ガス発生剤
WO1998029361A1 (fr) * 1996-12-28 1998-07-09 Nippon Kayaku Kabushiki-Kaisha Agent gazogene pour airbag

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3733177C1 (de) * 1987-10-01 1989-05-11 Bayern Chemie Gmbh Flugchemie Gaserzeugende Masse
JPH06239683A (ja) 1993-02-15 1994-08-30 Daicel Chem Ind Ltd エアバッグ用ガス発生剤
WO1995018780A1 (fr) * 1994-01-10 1995-07-13 Thiokol Corporation Compositions contenant des sels de dicyanamide generant des gaz non acides
US5557062A (en) * 1994-12-13 1996-09-17 United Technologies Corporation Breathable gas generators
JPH10130086A (ja) 1996-10-23 1998-05-19 Nippon Kayaku Co Ltd エアバッグ用ガス発生剤
WO1998029361A1 (fr) * 1996-12-28 1998-07-09 Nippon Kayaku Kabushiki-Kaisha Agent gazogene pour airbag
EP0952131A1 (fr) * 1996-12-28 1999-10-27 Nippon Kayaku Kabushiki Kaisha Agent gazogene pour airbag

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1074533A1 (fr) * 1999-08-06 2001-02-07 Nihon Plast Co., Ltd. Agent générateur de gaz

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Publication number Publication date
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