EP1064242B1 - Propellants for gas generator - Google Patents

Propellants for gas generator Download PDF

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Publication number
EP1064242B1
EP1064242B1 EP99919100A EP99919100A EP1064242B1 EP 1064242 B1 EP1064242 B1 EP 1064242B1 EP 99919100 A EP99919100 A EP 99919100A EP 99919100 A EP99919100 A EP 99919100A EP 1064242 B1 EP1064242 B1 EP 1064242B1
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EP
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Prior art keywords
propellant
component
gas generators
generators according
gas
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EP99919100A
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German (de)
French (fr)
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EP1064242A1 (en
Inventor
Eduard Gast
Bernhard Schmid
Peter Semmler
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Nigu Chemie GmbH
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Nigu Chemie GmbH
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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
    • C06B23/00—Compositions characterised by non-explosive or non-thermic constituents
    • 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
    • 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

Definitions

  • the invention relates to solid gas generator propellants (gas-generating mixtures), mainly for gas generator propellants for airbags and belt tensioners based on nitrogen-rich and low-carbon fuels possible, the solid gas generator fuels additionally contain a high-melting, substantially chemically inert Schlackenflinder in highly dispersed form, which acts as an internal filter and the formation and the discharge of dust-like particles from the gas generator housing largely prevented.
  • the invention thus relates to a method for intercepting the liquid or solid combustion products or dusty slag parts within the gas generator propellant immediacy in the emergence, so that manages with a simple structured filter pack in the gas generator housing.
  • the invention further relates to the use of catalysts based on platinum metals (Ru, Os, Rh, Ir, Pd, Pt) or metal alloys of platinum metals or copper on the slag traps as carriers in solid gas generator fuels, in particular the use in fixed gas turbine inflator propellants.
  • platinum metals Ru, Os, Rh, Ir, Pd, Pt
  • metal alloys of platinum metals or copper on the slag traps as carriers in solid gas generator fuels, in particular the use in fixed gas turbine inflator propellants.
  • An airbag consists essentially of a gas generator housing, which is filled with the gas generator propellant, usually in tablet form, and a primer (squib) for igniting the gas generator propellant, as well as a gas bag.
  • a primer for igniting the gas generator propellant
  • Suitable detonators are described, for example, in US Pat. No. 4,931,111.
  • the initially small folded airbag is filled after the initial ignition of the resulting gas during combustion of the gas generator propellant and reached in a period of about 10-50 ms its full volume. Of the Escape of hot sparks, melts or solids from the gas generator in the gas bag must be largely prevented because it could lead to destruction of the gas bag or injury to vehicle occupants. This is achieved by binding and filtering the slag resulting from the combustion of the gas generator propellant.
  • DE-A-44 35 790 gas generator propellants based on guanidine compounds on suitable carriers are known which have substantially improved burn-off behavior and improved slag formation.
  • DE-A-44 35 790 gives no indication of the use of refractory, substantially inert slag scavengers in highly dispersed form or of catalysts in gas generator propellants.
  • the gas-generating mixture described in EP-B-0 482 852 comprises a) a fuel selected from aminotetrazole, tetrazole, bitetrazole and metal salts of these compounds and triazole compounds and metal salts of triazole compounds; b) an oxygen-containing oxidation compound selected from alkali metal, alkaline earth metal, lanthanide and ammonium nitrates and perchlorates and alkali metal and alkaline earth metal chlorates and peroxides; and either c) a high temperature slag forming material selected from alkaline earth metal oxides, hydroxides, carbonates, oxalates, peroxides, nitrates, chlorates and perchlorates and alkaline earth metal salts of tetrazoles, bitetrazoles and triazoles, and d) a low
  • the main advantage of such a gas generator propellant is the favorable formation of a slag, which can easily be filtered off from the gaseous combustion products formed. Another advantage is the high gas yield.
  • U.S. Patent No. 4,948,439 mentions the problem of the formation of toxic gaseous burnup products by the same inventor when using azide replacements such as tetrazole compounds (e.g., aminotetrazole and its metal salts) and mixtures thereof in gas generator propellants.
  • azide replacements such as tetrazole compounds (e.g., aminotetrazole and its metal salts) and mixtures thereof in gas generator propellants.
  • the problem is the speed with which the airbag must be inflated (10-50 ms), if in addition still ambient air must be sucked.
  • the catalyst consists of a metal or a metal alloy, preferably a pyrophoric metal or a pyrophoric metal alloy on a support.
  • the carrier is a silicate, preferably a layer or framework silicate.
  • metal in particular Ag has proven.
  • the known fuels used include triaminoguanidine nitrate (TAGN), nitroguanidine (NIGU or NQ), 3-nitro-1,2,3-triazol-5-one and especially diguanidinium-5,5'-azotetrazolate (GZT).
  • gas-generating mixtures described in DE-C-44 01 213 and DE-C-44 01 214 do not contain low-melting and high-melting slag formers or slag scavengers according to the invention, but rather claim that slag formers can be dispensed with there.
  • a part of the refractory slag catcher according to the invention can act here as a support for a platinum metal or for a metal alloy of platinum metals and thus as a catalyst component.
  • catalyst is used in an expanded sense and represents an active reaction component which can be reacted itself and acts to be reaction-promoting and / or reaction-accelerating.
  • the definition of the catalyst further includes that this is added to the Letsgemsich in a very low concentration.
  • the proportion of "catalyst" in the gas-generating mixture is up to 30% by mass and is thus more significant, even proportionately, part of the gas-generating mixture.
  • the present invention is based on the object of the present invention to provide improved gas generator fuels, in particular for airbags, whose burning behavior can be adjusted specifically and in particular the formation of toxic gases and respirable, dust-like components that may escape from the inflator housing.
  • the gas generator propellants produced from the gas generator fuels should be thermally stable, easy to ignite, fast - even at low temperature - burning and easy to store and ensure a high gas yield.
  • these gas generator propellant to allow a reduction in size, reduction in the number of components or simplification of the gas generator housing and thus their weight reduction compared to known generators.
  • Preferred fuels are nitroguanidine (NIGU), 5-aminotetrazole (ATZ), dicyandiamide (DCD), dicyanamide, their salts, especially sodium and calcium dicyanamide and guanidinium nitrate, and mixtures thereof.
  • NIGU nitroguanidine
  • ATZ 5-aminotetrazole
  • DCD dicyandiamide
  • dicyanamide their salts, especially sodium and calcium dicyanamide and guanidinium nitrate, and mixtures thereof.
  • the combustion gas yield is high, producing a large amount of nitrogen gas.
  • Alkali Li, Na, K
  • alkaline earth salts Mg, Ca, Sr, Ba
  • alkali or alkaline earth nitrates such as lithium nitrate, sodium nitrate, potassium nitrate, magnesium nitrate, calcium nitrate, strontium nitrate or barium nitrate
  • ammonium nitrate alkali metal or alkaline earth chlorates or perchlorates (such as lithium, sodium, potassium, magnesium -, calcium, strontium or barium chlorate and lithium, sodium, potassium, magnesium, calcium, strontium or barium perchlorate) and ammonium perchlorate and mixtures thereof.
  • potassium nitrate and strontium nitrate are used.
  • Strontium nitrate is non-hygroscopic, non-toxic and allows a high gas yield when burned. Potassium nitrate also has a low burning temperature.
  • Al 2 O 3 , TiO 2 and ZrO 2 in highly dispersed form or mixtures thereof are used as high-melting, substantially chemically inert slag scavengers, component (C) where Al 2 O 3 is a BET surface area (based on DIN 66131) of 100 +/- 15 m 2 / g (mp point about 2050 ° C), TiO 2 a BET surface area of 50 +/- 15 m 2 / g (mp point about 1850 ° C) and ZrO 2 a / BET surface area of 40 +/- 10 m 2 / g (mp point about 2700 ° C) have.
  • These highly dispersed oxides are commercially available, for example, under the trade names aluminum oxide C, titanium oxide P25 and VP zirconium oxide (Degussa AG).
  • pyrogenic oxides are prepared by reacting the metal chlorides with H 2 and O 2 in the appropriate molar ratio by gas phase reaction (flame hydrolysis). she have no pores and defined agglomerates, as is otherwise the case with the production in the wet process.
  • slag scavenger component (C)
  • component (C) is understood to mean refractory, essentially chemically inert metal oxides in highly dispersed form, i. these oxides have a much larger surface area than the oxides in their conventional form.
  • conventional Al 2 O 3 as ⁇ -oxide has a BET surface area of only 5-10 m 2 / g, conventional pigment TiO 2 a BET surface area of only 5-10 m 2 / g, and conventional ZrO 2 a BET Surface area of only 3-8 m 2 / g (for refractory products), whereas the metal oxides used in the gas generator propellants of the present invention have BET surface areas of from about 40 to about 100 m 2 / g, more preferably from about 50 to about 100 m 2 / g and in particular about 100 m 2 / g.
  • the slag scavengers of the present invention are characterized by their high melting point of about 1850 to about 2700 ° C from. These high melting points cause the slag scavengers not to melt during the reaction and thus act as solids.
  • the slag scavengers of the present invention are essentially chemically inert compounds, ie the slag scavengers of the present invention do not participate in the combustion reaction of the gas generator propellants to chemical reactions or only to a minor extent on the surface of the slag scavenger metal oxides.
  • the high-resolution space lattice ie the large inner surface of eg Al 2 O 3 , TiO 2 or ZrO 2 on the one hand causes by their inactivity, the cooling of the combustion products and stored on the other hand specially liquid and / or solid slag parts or particles that are formed during combustion ,
  • the tablet form, in which the gas generator propellant charges are used is maintained during and after the burn-up, or it is possible to easily filter any resulting fragments. This means that hardly any dust forms, which could escape during combustion from the gas generator propellant charge and thus from the gas generator housing.
  • the slag catchers work
  • Pulmonary dust-like particles have a diameter of about 6 ⁇ m or smaller.
  • alkali metal and alkaline earth metal carbonates such as sodium carbonate, potassium carbonate, magnesium carbonate, calcium carbonate, strontium carbonate or barium carbonate
  • alkali metal or alkaline earth metal oxides such as sodium, potassium, magnesium, calcium, strontium or barium oxide
  • Silicates such as hectorite
  • aluminates such as sodium beta-aluminate (Na 2 O 11 Al 2 O 3 ) or tricalcium aluminate (Ca 3 Al 2 O 6 )
  • aluminum silicates such as bentonites or zeolites
  • iron (III) oxide or mixtures thereof are used.
  • Component (D) serves to form an easily filterable slag during combustion of the gas generator fuel.
  • the slag former, component (D) may additionally act as a coolant.
  • the silicates, aluminates and aluminum silicates react with the alkali metal and Erdalkalimetalloxiden that arise during combustion.
  • the invention further relates to the use of catalysts based on platinum metals (Ru, Os, Rh, Ir, Pd, Pt) or metal alloys of platinum metals or copper on the highly dispersed slag scavenger carriers in the solid gas generator propellants of the present invention, in particular the use in fixed gas generator propellants for airbags.
  • platinum metals Ru, Os, Rh, Ir, Pd, Pt
  • metal alloys of platinum metals or copper on the highly dispersed slag scavenger carriers in the solid gas generator propellants of the present invention, in particular the use in fixed gas generator propellants for airbags.
  • a part of the slag trap (component (C)) can serve as a carrier on which a platinum metal or a metal alloy of platinum metals or copper in a catalytically effective layer thickness is applied.
  • Platinum metals include ruthenium (Ru), osmium (Os), rhodium (Rh), iridium (Ir), palladium (Pd), and platinum (Pt).
  • the catalysts used in the present invention are preferably based on Rh, Pd or Pt and in particular Pt.
  • metal alloys of platinum metals are all catalytically active metal alloys of the abovementioned platinum metals, preferably Pt / Pd and Pt / Rh alloys.
  • the metals or metal alloys of platinum metals are applied in a catalytically active layer thickness, preferably in a monatomic layer ("monolayer") on the support.
  • the catalysts are contained in only catalytic amounts in the gas generator propellant. Their proportion by weight of the component (C) is 0.1-5 wt .-%, preferably 0.2-1.2 wt .-% of the component (C).
  • Preferred catalysts are those in which the highly dispersed carrier is Al 2 O 3 and the metal is Pt, Pd or Cu, in particular Pt.
  • Suitable catalysts are available from Degussa AG, eg 1% Pt on gamma Al 2 O 3 or 1% Pd + Pt on gamma Al 2 O 3 .
  • the catalysts serve to control the reaction so that hardly toxic gaseous combustion products, such as carbon monoxide (CO), nitrogen oxides (NO x ) and ammonia (NH 3 ) are formed.
  • gaseous combustion products such as carbon monoxide (CO), nitrogen oxides (NO x ) and ammonia (NH 3 ) are formed.
  • the above-mentioned catalysts are particularly well suited for use in gas generator propellants in airbags.
  • the catalysts may be triggered, i. used airbags, as well as from unreleased, i. be recycled from old-vehicle airbags according to previously known procedures. This leads to a waste relief of the environment and allows the reuse of the catalyst metals.
  • the catalyst metal or the metal alloy is not oxidized during the burnup.
  • the catalyst need not be added as an additional component to the gas generator propellant, but the catalyst is part of an already present in the gas generator propellant component (component C)).
  • Component (A) is present in an amount of from about 20 to 60% by weight, preferably from about 28 to 52% by weight and in particular from about 45 to 51% by weight, component (B) in an amount of about 38 to about 63 wt .-%, preferably from about 38 to about 55 wt .-% and in particular from about 39 to 45 wt .-% before, component (C) in an amount of about 5 to 22 wt .-%, preferably from about 8 to 20% by weight and in particular from about 9 to 11% by weight and component (D), if present, in an amount of about 2 to 12% by weight, preferably from about 4 to 10% by weight .-% before, in each case based on the total composition of the gas generator propellant.
  • the gas generator fuel may further contain as component (E) a water-soluble binder at room temperature.
  • Preferred binders are cellulose compounds or polymers of one or more polymerizable olefinically unsaturated monomers.
  • examples of cellulose compounds are cellulose ethers, such as carboxymethylcellulose, methylcellulose ethers, in particular methylhydroxyethylcellulose.
  • a good usable methylhydroxyethylcellulose is CULMINAL® MHEC 30000 PR from Aqualon.
  • Suitable polymers having a binding effect are polyvinylpyrrolidone, polyvinyl acetate, Polyvinyl alcohol and polyvinyl butyral, eg Pioloform® B (Wacker Chemie, Burghausen).
  • component (E) a metal salt of stearic acid insoluble in water at room temperature, such as aluminum stearate, magnesium stearate, calcium stearate or zinc stearate, may also be used.
  • Graphite is also suitable as a binder.
  • Component (E) is present in an amount of from 0 to 2% by weight, and preferably from 0.3 to 0.8% by weight.
  • the binder, component (E) serves as a desensitizer and as a processing aid in the production of granules or pellets from the gas generator fuel. It also serves to reduce the hydrophilicity and to stabilize the gas generator propellant charges.
  • gas generant fuels Examples 1 to 57 of Table I below
  • gas generator propellants were prepared according to the following procedure:
  • the roughly premixed raw materials (components (A), (B), (C) and optionally (D) and (E)) were ground or precompressed by means of a ball mill.
  • the granulation of the gas generator fuel mixture was carried out in a vertical mixer by adding about 20% water while stirring and at a temperature increased to about 40 ° C. After brief flash-off, the resulting blend was rubbed at room temperature through a 1 mm screen through-hole machine. The granules thus obtained were dried for about 2 hours in a drying oven at 80 ° C.
  • the finished granulate of the gas generator fuel (particle size distribution 0-1 mm) was then pressed into tablets (pellets) using a rotary press. These gas generator propellant pellets were post-dried at 80 ° C in a drying oven.
  • the tablets or pellets from the gas generator fuel used in the gas generators can be prepared by known methods, such as extruding, extruding, in rotary presses or tableting machines.
  • the size of the pellets or tablets depends on the desired firing time in the particular application.
  • the gas generator fuel of the invention consists of non-toxic, easy to produce and inexpensive components whose processing is straightforward.
  • the less cost-effective component, namely, the catalyst metal, can be recycled by known methods.
  • the thermal stability of the components causes a good shelf life.
  • the ignitability of the mixtures is good. They burn quickly and deliver high gas yields with very low CO, NO x and NH 3 levels below the allowable limit.
  • the mixtures according to the invention are therefore particularly suitable for use as gas generants in the various airbag systems, as extinguishing agents or propellants.
  • Examples 1 to 57 below illustrate the invention, but do not limit it.
  • Examples 15, 18 and 21 are comparative examples using conventional ZrO 2 , TiO 2 and Al 2 O 3 .
  • Table I ⁇ / u>
  • the indexes specified in the table have the following meaning: 1 Titanium Dioxide P25, Degussa AG 2 Zirconium oxide VP, Degussa AG 3 Alumina C, Degussa AG 4 Titanium dioxide Kronos 3025, Kronos Titan GmbH 5 Zirconia, Merck 6 Alumina NO 615-30 II 24, Nabaltec 7 Oxide. Catalyst 1% Pt on gamma-alumina, Degussa AG 8th Oxide.
  • burn-offs were carried out in a practical gas generator housing for the 60-liter driver's airbag, with original dimensions, lighters and filter pack made of stainless steel.
  • the gas generator propellant weight used was 50 to 55 g, depending on the gas yield of the respective gas generator fuel formulation.
  • the pellets had a diameter of 4 to 6 mm, with a pellet height of 1.5 or 2.1 mm.
  • Gas yield and temperature are within the range favorable for gas generator propellants for airbags.
  • the measured values for CO, NO x and NH 3 given in the table above refer to a 60 liter can. These are good values for a non-optimized experimental gas generator.
  • compositions are those of Examples 14, 17 and 20.
  • thermodynamic data of the individual gas formulations were calculated on the oxygen balance surplus, which promised the least possible toxic gas evolution during combustion.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Combustion & Propulsion (AREA)
  • Inorganic Chemistry (AREA)
  • Catalysts (AREA)
  • Air Bags (AREA)
  • Feeding, Discharge, Calcimining, Fusing, And Gas-Generation Devices (AREA)
  • Physical Or Chemical Processes And Apparatus (AREA)
  • Glass Compositions (AREA)

Abstract

The present invention relates to solid propellants for gas generators (gas-generating mixtures), wherein said propellants are mainly intended for use in propelling charges for gas generators used in airbags or seat-belt pre-tensioning devices. The solid propellants for gas generators further include an essentially chemically-inert slag trap which has a high fusion point and a good dispersion, wherein said slag trap acts as an inner filter and globally prevents the formation of powder particles as well as their exit from the housing of the gas generator. A portion of the slag trap having a good dispersion may be used as a carrier substance for catalyst metals.

Description

Die Erfindung betrifft feste Gasgeneratortreibstoffe (gaserzeugende Mischungen), hauptsächlich für Gasgeneratortreibsätze für Airbags und Gurtstraffer auf Basis von stickstoffreichen und möglichst kohlenstoffarmen Brennstoffen, wobei die festen Gasgeneratortreibstoffe zusätzlich einen hochschmelzenden, im wesentlichen chemisch inerten Schlackenfänger in hochdisperser Form enthalten, der als internes Filter wirkt und die Entstehung und den Austritt von staubförmigen Teilchen aus dem Gasgeneratorgehäuse weitgehend verhindert.The invention relates to solid gas generator propellants (gas-generating mixtures), mainly for gas generator propellants for airbags and belt tensioners based on nitrogen-rich and low-carbon fuels possible, the solid gas generator fuels additionally contain a high-melting, substantially chemically inert Schlackenfänger in highly dispersed form, which acts as an internal filter and the formation and the discharge of dust-like particles from the gas generator housing largely prevented.

Die Erfindung betrifft somit ein Verfahren zum Abfangen der flüssigen bzw. festen Verbrennungsprodukte bzw. staubförmigen Schlackenteile innerhalb des Gasgeneratortreibsatzes unmitttelbar bei der Entstehung, so daß man mit einem einfach strukturierten Filterpaket im Gasgeneratorgehäuse auskommt.The invention thus relates to a method for intercepting the liquid or solid combustion products or dusty slag parts within the gas generator propellant immediacy in the emergence, so that manages with a simple structured filter pack in the gas generator housing.

Die Erfindung betrifft ferner die Verwendung von Katalysatoren auf der Basis von Platinmetallen (Ru, Os, Rh, Ir, Pd, Pt) oder Metallegierungen aus Platinmetallen oder Kupfer auf den Schlackenfängern als Träger in festen Gasgeneratortreibstoffen, insbesondere die Verwendung in festen Gasgeneratortreibsätzen für Airbags.The invention further relates to the use of catalysts based on platinum metals (Ru, Os, Rh, Ir, Pd, Pt) or metal alloys of platinum metals or copper on the slag traps as carriers in solid gas generator fuels, in particular the use in fixed gas turbine inflator propellants.

Ein Airbag besteht im wesentlichen aus einem Gasgeneratorgehäuse, das mit dem Gasgeneratortreibsatz, in der Regel in Tablettenform, gefüllt ist, und einem Initialzünder (squib) zur Zündung des Gasgeneratortreibsatzes, sowie einem Gassack. Geeignete Zünder sind beispielsweise in der US-PS 4,931,111 beschrieben. Der zunächst kleingefaltete Gassack wird nach der Initialzündung von den beim Abbrand des Gasgeneratortreibsatzes entstehenden Gasen gefüllt und erreicht in einem Zeitraum von etwa 10-50 ms sein volles Volumen. Der Austritt von heißen Funken, Schmelzen oder Festkörpern aus dem Gasgenerator in den Gassack muß weitgehend verhindert werden, da er zu einer Zerstörung des Gassacks oder zur Verletzung von Fahrzeuginsassen führen könnte. Dies wird durch Binden und Filtrieren der Schlacke erreicht, die bei der Verbrennung des Gasgeneratortreibsatzes entsteht.An airbag consists essentially of a gas generator housing, which is filled with the gas generator propellant, usually in tablet form, and a primer (squib) for igniting the gas generator propellant, as well as a gas bag. Suitable detonators are described, for example, in US Pat. No. 4,931,111. The initially small folded airbag is filled after the initial ignition of the resulting gas during combustion of the gas generator propellant and reached in a period of about 10-50 ms its full volume. Of the Escape of hot sparks, melts or solids from the gas generator in the gas bag must be largely prevented because it could lead to destruction of the gas bag or injury to vehicle occupants. This is achieved by binding and filtering the slag resulting from the combustion of the gas generator propellant.

Herkömmliche Gasgeneratortreibsätze für die Verwendung in Airbags auf der Basis von Natriumazid sind seit längerem bekannt. Die Verwendung des hochtoxischen Natriumazids erfordert jedoch ein aufwendiges und kostspieliges Herstellungsverfahren der Gasgeneratortreibsätze. Zudem führt die weltweit ständig zunehmende Zahl von nicht abgebrannten Gasgeneratortreibsätzen in Alt-Kraftfahrzeugen zu einem Entsorgungs- und Sicherheitsproblem.Conventional gas generator propellants for use in sodium azide based airbags have been known for some time. However, the use of the highly toxic sodium azide requires a costly and expensive manufacturing process of the gas generator propellants. In addition, the worldwide increase in the number of unlabelled gas generator propellants in old vehicles is causing a disposal and safety problem.

In den vergangenen Jahren wurden daher Anstrengungen unternommen, geeignete Ersatzstoffe für Natriumazid zu finden.Efforts have therefore been made in recent years to find suitable substitutes for sodium azide.

Aus der DE-A-44 35 790 sind Gasgeneratortreibstoffe auf der Basis von Guanidinverbindungen auf geeigneten Trägern bekannt, die im wesentlichen ein verbessertes Abbrandverhalten und eine verbesserte Schlackenbildung aufweisen. Die DE-A-44 35 790 gibt keine Hinweise auf die Verwendung von hochschmelzenden, im wesentlichen inerten Schlackenfängern in hochdisperser Form oder von Katalysatoren in Gasgeneratortreibsätzen.From DE-A-44 35 790 gas generator propellants based on guanidine compounds on suitable carriers are known which have substantially improved burn-off behavior and improved slag formation. DE-A-44 35 790 gives no indication of the use of refractory, substantially inert slag scavengers in highly dispersed form or of catalysts in gas generator propellants.

Aus der EP-B-0 482 852 und dem dort zitierten Stand der Technik sind azid freie Gasgeneratortreibsätze, insbesondere für Airbags, bekannt. Die in der EP-B-0 482 852 beschriebene, gaserzeugende Mischung enthält a) einen Treibstoff, ausgewählt aus Aminotetrazol, Tetrazol, Bitetrazol und Metallsalzen dieser Verbindungen und Triazolverbindungen und Metallsalzen von Triazolverbindungen; b) eine sauerstoffhaltige Oxidationsverbindung, ausgewählt aus Alkalimetall-, Erdalkalimetall-, Lanthanid- und Ammoniumnitraten und -perchloraten und Alkalimetall- und Erdalkalimetallchloraten und -peroxiden; und entweder c) ein Hochtemperatur-Schlackenbildungsmaterial, ausgewählt aus Erdalkalimetalloxiden, -hydroxiden, -carbonaten, -oxalaten, -peroxiden, -nitraten, -chloraten und -perchloraten und Erdalkalimetallsalzen von Tetrazolen, Bitetrazolen und Triazolen, und d) ein Niedertemperatur-Schlackenbildungsmaterial, ausgewählt aus Siliciumdioxid, Boroxid, Vanadiumpentoxid, natürlich vorkommenden Tonen und Talken, Alkalimetallsilikaten, -boraten, -carbonaten, -nitraten, -perchloraten und -chloraten und Alkalimetallsalzen von Tetrazolen, Bitetrazolen und Triazolen; oder e) ein Hochtemperatur-Schlackenbildungsmaterial, ausgewählt aus Übergangsmetalloxiden, -hydroxiden, -carbonaten, -oxalaten, -peroxiden, -nitraten, -chloraten- und perchloraten; und f) ein Niedertemperatur-Schlackenbildungsmaterial, welches Siliciumdioxid ist; wobei die Menge von d) oder f) ausreicht, um zur Bildung einer kohärenten Masse oder Schlacke zu führen, aber nicht so hoch ist, daß eine Flüssigkeit mit niederer Viskosität entsteht, wobei es sich versteht, daß ein einzelnes Material für mehr als eine der Kategorien dienen kann.From EP-B-0 482 852 and the prior art cited therein, azide-free gas generator propellants, in particular for airbags, are known. The gas-generating mixture described in EP-B-0 482 852 comprises a) a fuel selected from aminotetrazole, tetrazole, bitetrazole and metal salts of these compounds and triazole compounds and metal salts of triazole compounds; b) an oxygen-containing oxidation compound selected from alkali metal, alkaline earth metal, lanthanide and ammonium nitrates and perchlorates and alkali metal and alkaline earth metal chlorates and peroxides; and either c) a high temperature slag forming material selected from alkaline earth metal oxides, hydroxides, carbonates, oxalates, peroxides, nitrates, chlorates and perchlorates and alkaline earth metal salts of tetrazoles, bitetrazoles and triazoles, and d) a low temperature slag forming material, selected from silica, boric oxide, vanadium pentoxide, naturally occurring clays and talcs, alkali metal silicates, borates, carbonates, nitrates, perchlorates and chlorates and alkali metal salts of tetrazoles, bitetrazoles and triazoles; or e) a high temperature slag forming material selected from transition metal oxides, hydroxides, carbonates, oxalates, peroxides, nitrates, chlorates and perchlorates; and f) a low temperature slag forming material which is silica; wherein the amount of d) or f) is sufficient to result in the formation of a coherent mass or slag but is not so high as to produce a low viscosity liquid, it being understood that a single material may be used for more than one of Categories can serve.

Der wesentliche Vorteil eines derartigen Gasgeneratortreibsatzes liegt in der günstigen Bildung einer Schlacke, die leicht von den gebildeten gasförmigen Abbrandprodukten abfiltriert werden kann. Ein weiterer Vorteil besteht in der hohen Gasausbeute.The main advantage of such a gas generator propellant is the favorable formation of a slag, which can easily be filtered off from the gaseous combustion products formed. Another advantage is the high gas yield.

Nachteile derartiger Gasgeneratortreibsätze sind jedoch, daß hinsichtlich der Bereitstellung eines Gasgeneratortreibsatzes mit einer möglichst günstigen Schlackenbildung Kompromisse beim Abbrandverhalten (Abbrandgeschwindigkeit), bei der Gasbildung, den Eigenschaften hinsichtlich der Herstellung der Pellets und anderen Verfahrensfaktoren und insbesondere bei der Gasqualität, d.h. dem Anteil von toxischen gasförmigen Abbrandprodukten eingegangen werden mußten. Weiterhin ist die Anzahl der geeigneten Treibstoffe relativ begrenzt.Disadvantages of such gas generator propellants are, however, that in terms of providing a gas generator propellant with the lowest possible slag forming compromises in burning behavior (burning rate), in gas formation, the properties of the production of pellets and other process factors and in particular in the gas quality, i. the proportion of toxic gaseous combustion products had to be addressed. Furthermore, the number of suitable fuels is relatively limited.

In der EP-B-0 482 852 gibt es keine Hinweise darauf, wie diese Probleme durch eine Modifizierung der Zusammensetzung des Gasgeneratortreibsatzes gelöst werden können.In EP-B-0 482 852 there is no indication as to how these problems can be solved by modifying the composition of the gas generator propellant.

In der US-PS 4,948,439 wird von dem gleichen Erfinder auf die Problematik hinsichtlich der Bildung von toxischen gasförmigen Abbrandprodukten bei der Verwendung von Azid-Ersatzstoffen, wie Tetrazolverbindungen (z.B. Aminotetrazol und dessen Metallsalze) und deren Gemische in Gasgeneratortreibsätzen hingewiesen.U.S. Patent No. 4,948,439 mentions the problem of the formation of toxic gaseous burnup products by the same inventor when using azide replacements such as tetrazole compounds (e.g., aminotetrazole and its metal salts) and mixtures thereof in gas generator propellants.

In der US-PS 4,948,439 wird jedoch kein Lösungsvorschlag beschrieben, wie der Anteil an toxischen gasförmigen Abbrandprodukten bei der Verbrennung von Gasgeneratortreibsätzen, die als Treibstoff Tetrazol- oder Triazolverbindungen, deren Metallsalze oder Gemische davon enthalten, reduziert werden könnte. Vielmehr wird ein Verfahren zum Aufblasen eines Airbags beschrieben, bei dem zunächst ein Primärgasgemisch durch die Zündung eines Gasgeneratortreibsatzes entsteht, der als Treibstoff mindestens eine Tetrazol- oder Triazolverbindung enthält und dieses Primärgemisch wird durch Vermischen mit Umgebungsluft derart verdünnt, daß der Gehalt an toxischen gasförmigen Abbrandprodukten aus dem Primärgasgemisch auf ein toxikologisch akzeptables Maß gesenkt wird.However, US Pat. No. 4,948,439 does not disclose a solution proposal on how to reduce the proportion of toxic gaseous burnup products in the combustion of gas generator propellants which contain as fuel tetrazole or triazole compounds, their metal salts or mixtures thereof. Rather, a method of inflating a Airbags described in which initially a primary gas mixture is formed by the ignition of a gas generator propellant containing as fuel at least one tetrazole or triazole compound and this primary mixture is diluted by mixing with ambient air such that the content of toxic gaseous Abbrandprodukten from the primary gas mixture to a toxicologically acceptable Measure is lowered.

Das Vermischen mit der Umgebungsluft führt zu einer Verkomplizierung (Größe, Aufbau, etc.) des gesamten Airbag-Systems. Problematisch ist die Geschwindigkeit, mit der der Airbag aufgeblasen werden muß (10-50 ms), wenn zusätzlich noch Umgebungsluft angesaugt werden muß.The mixing with the ambient air leads to a complication (size, structure, etc.) of the entire airbag system. The problem is the speed with which the airbag must be inflated (10-50 ms), if in addition still ambient air must be sucked.

Aus der DE-C-44 01 213 sind gaserzeugende Mischungen aus einem Brennstoff, einem Oxidator, einem "Katalysator" und einem Kühlmittel, dadurch gekennzeichnet, daß der Oxidator Cu(NO3)2·3Cu(OH)2 und der Katalysator ein Metalloxid oder eine Metalloxidmischung oder ein Metallmischoxid ist, bekannt.From DE-C-44 01 213 gas-generating mixtures of a fuel, an oxidizer, a "catalyst" and a coolant, characterized in that the oxidizer Cu (NO 3 ) 2 · 3Cu (OH) 2 and the catalyst is a metal oxide or a metal oxide mixture or a mixed metal oxide is known.

Aus der DE-C-44 01 214 sind zudem gaserzeugende Mischungen ähnlicher Zusammensetzungen bekannt, bei denen der Katalysator aus einem Metall oder einer Metallegierung, vorzugsweise einem pyrophoren Metall oder einer pyrophoren Metallegierung auf einem Träger besteht. Bei dem Träger handelt es sich um ein Silikat, vorzugsweise ein Schicht- oder Gerüstsilikat. Als Metall hat sich insbesondere Ag bewährt. Zu den bekannten verwendeten Brennstoffen zählen Triaminoguanidinnitrat (TAGN), Nitroguanidin (NIGU bzw. NQ), 3-Nitro-1,2,3-triazol-5-on und insbesondere Diguanidinium-5,5'-azotetrazolat (GZT).From DE-C-44 01 214 also gas-generating mixtures of similar compositions are known, in which the catalyst consists of a metal or a metal alloy, preferably a pyrophoric metal or a pyrophoric metal alloy on a support. The carrier is a silicate, preferably a layer or framework silicate. As metal, in particular Ag has proven. The known fuels used include triaminoguanidine nitrate (TAGN), nitroguanidine (NIGU or NQ), 3-nitro-1,2,3-triazol-5-one and especially diguanidinium-5,5'-azotetrazolate (GZT).

Der wesentliche Vorteil der in den beiden vorstehenden deutschen Patentschriften beschriebenen gaserzeugenden Mischungen soll in der Herabsetzung der Verbrennungstemperatur und in der Erhöhung der Abbrandgeschwindigkeit liegen.The main advantage of the gas-generating mixtures described in the two preceding German patents is to reduce the combustion temperature and increase the burning rate.

Die in der DE-C-44 01 213 und DE-C-44 01 214 beschriebenen gaserzeugenden Mischungen enthalten keine niedrig- und hochschmelzenden Schlackenbildner bzw. keine erfindungsgemäßen Schlackenfänger, vielmehr wird dort behauptet, daß auf Schlackenbildner verzichtet werden kann.The gas-generating mixtures described in DE-C-44 01 213 and DE-C-44 01 214 do not contain low-melting and high-melting slag formers or slag scavengers according to the invention, but rather claim that slag formers can be dispensed with there.

Entgegen dieser Behauptung haben die Erfinder der vorliegenden Erfindung gefunden, daß die Verwendung von niedrig- und hochschmelzenden Schlackenbildnern, insbesondere der erfindungsgemäßen Schlackenfänger eine deutliche Reduzierung von toxischen gasförmigen Abbrandprodukten bewirkt. Ein Teil des hochschmelzenden erindungsgemäßen Schlackenfängers kann hierbei als Träger für ein Platinmetall bzw. für eine Metallegierung aus Platinmetallen und somit als Katalysatorbestandteil fungieren.Contrary to this claim, the inventors of the present invention have found that the use of low and high melting slag formers, in particular slag scavengers according to the invention causes a significant reduction of toxic gaseous Abbrandprodukten. A part of the refractory slag catcher according to the invention can act here as a support for a platinum metal or for a metal alloy of platinum metals and thus as a catalyst component.

In den beiden vorstehend genannten deutschen Patentschriften wird der Begriff "Katalysator" in einem erweiterten Sinn verwendet und stellt einen aktiven Reaktionsbestandteil dar, der selbst umgesetzt werden kann und reaktionslenkend und/oder reaktionsbeschleunigend wirkt.In the two German patents mentioned above, the term "catalyst" is used in an expanded sense and represents an active reaction component which can be reacted itself and acts to be reaction-promoting and / or reaction-accelerating.

Es handelt sich demnach nicht um einen Katalysator im eigentlichen Sinn, da ein Katalysator bei einer Umsetzung keinen Reaktionsbestandteil darstellt. Ein Katalysator im eigentlichen Sinn wird bei Umsetzungen nicht verbraucht, d.h. nicht umgesetzt.It is therefore not a catalyst in the strict sense, since a catalyst in a reaction is not a reaction component. A catalyst in the true sense is not consumed in reactions, i. Not translated.

Zur Definition des Katalysators gehört ferner, daß dieser in einer nur sehr geringen Konzentration dem Reaktionsgemsich beigemengt wird. In den beiden deutschen Patentschriften beträgt jedoch der Anteil an "Katalysator" in der gaserzeugenden Mischung bis zu 30 Massen-% und ist damit wesentlicher, auch anteilsmäßig, Bestandteil der gaserzeugenden Mischung.The definition of the catalyst further includes that this is added to the Reaktionsgemsich in a very low concentration. In the two German patents, however, the proportion of "catalyst" in the gas-generating mixture is up to 30% by mass and is thus more significant, even proportionately, part of the gas-generating mixture.

Aus dem zuvor gesagten ergibt sich, daß in der DE-C-44 01 213 und DE-C-44 01 214 zwar der Begriff "Katalysator" verwendet wird, aber, wie dies auch in den beiden Patentschriften angedeutet ist, die Bedeutung nicht mit der herkömmlichen Definition eines Katalysators übereinstimmt.It can be seen from the above that in DE-C-44 01 213 and DE-C-44 01 214, although the term "catalyst" is used, but, as indicated in the two patents, the meaning not with the conventional definition of a catalyst matches.

Der vorliegenden Erfindung liegt gegenüber dem Stand der Technik die Aufgabe zugrunde, verbesserte Gasgeneratortreibstoffe, insbesondere für Airbags bereitzustellen, deren Abbrandverhalten sich gezielt einstellen läßt und die insbesondere die Entstehung von toxischen Gasen und von lungengängigen, staubförmigen Anteilen, die aus dem Gasgeneratorgehäuse austreten können, auf ein Minimum beschränken.The present invention is based on the object of the present invention to provide improved gas generator fuels, in particular for airbags, whose burning behavior can be adjusted specifically and in particular the formation of toxic gases and respirable, dust-like components that may escape from the inflator housing.

Die aus den Gasgeneratortreibstoffen hergestellten Gasgeneratortreibsätze sollen thermisch stabil, gut anzündbar, schnell - auch bei niedriger Temperatur - brennend und gut lagerfähig sein und eine hohe Gasausbeute gewährleisten. Zudem sollen diese Gasgeneratortreibsätze eine Verkleinerung, Reduzierung der Anzahl der Komponenten oder Vereinfachung der Gasgeneratorgehäuse und somit deren Gewichtsverminderung im Vergleich zu bekannten Generatoren ermöglichen.The gas generator propellants produced from the gas generator fuels should be thermally stable, easy to ignite, fast - even at low temperature - burning and easy to store and ensure a high gas yield. In addition, these gas generator propellant to allow a reduction in size, reduction in the number of components or simplification of the gas generator housing and thus their weight reduction compared to known generators.

Erfindungsgemäß werden diese Aufgaben durch einen Gasgeneratortreibstoff gelöst, umfassend

  • (A) mindestens einen Brennstoff aus der Gruppe umfassend Guanidiniumnitrat (GUNI; GuNO3), Dicyanamid, Ammoniumdicyanamid, Natriumdicyanamid (Na-DCA), Kupferdicyanamid, Zinndicyanamid, Calciumdicyanamid (Ca-DCA), Guanidiniumdicyanamid (GDCA), Aminoguanidiniumbicarbonat (AGB), Aminoguanidiniumnitrat (AGN), Triaminoguanidiniumnitrat (TAGN), Nitroguanidin (NIGU), Dicyandiamid (DCD), Azodicarbonamid (ADCA) sowie Tetrazol (HTZ), 5-Aminotetrazol (ATZ), 5-Nitro-1,2,4-triazol-3-on (NTO), deren Salze und deren Gemische,
  • (B) mindestens ein Alkali- oder Erdalkalinitrat oder Ammoniumnitrat, -chlorat oder -perchlorat,
  • (C) mindestens einen hochschmelzenden, im wesentlichen chemisch inerten Schlackenfänger, ausgewählt aus der Gruppe umfassend Al2O3, TiO2 und ZrO2 in hochdisperser Form oder Gemische davon, wie in Anspruch 1 definiert, und
gegebenenfalls (D) mindestens einen Schlackenbildner, ausgewählt aus Alkali- und Erdalkalimetallcarbonaten und -oxiden, Silikaten, Aluminaten und Aluminiumsilikaten, Eisen(III)oxid sowie Siliciumnitrid (Si3N4), das beim Abbrand Stickstoff (N2) und Siliciumdioxid (SiO2) zur Weiterreaktion liefert und gegebenenfalls (E) mindestens ein in Wasser bei Raumtemperatur lösliches Bindemittel.According to the invention, these objects are achieved by a gas generator fuel, comprising
  • (A) at least one fuel selected from the group consisting of guanidinium nitrate (GUNI; GuNO 3 ), dicyanamide, ammonium dicyanamide, sodium dicyanamide (Na-DCA), copper dicyanamide, tin dicyanamide, calcium dicyanamide (Ca-DCA), guanidinium dicyanamide (GDCA), aminoguanidinium bicarbonate (GTC), Aminoguanidinium nitrate (AGN), triaminoguanidinium nitrate (TAGN), nitroguanidine (NIGU), dicyandiamide (DCD), azodicarbonamide (ADCA) and tetrazole (HTZ), 5-aminotetrazole (ATZ), 5-nitro-1,2,4-triazole-3 -on (NTO), their salts and their mixtures,
  • (B) at least one alkali or alkaline earth nitrate or ammonium nitrate, chlorate or perchlorate,
  • (C) at least one refractory, substantially chemically inert slag scavenger selected from the group comprising Al 2 O 3 , TiO 2 and ZrO 2 in highly dispersed form or mixtures thereof as defined in claim 1, and
optionally (D) at least one slag former selected from alkali metal and alkaline earth metal carbonates and oxides, silicates, aluminates and aluminum silicates, ferric oxide and silicon nitride (Si 3 N 4 ), which upon combustion releases nitrogen (N 2 ) and silicon dioxide (SiO 2 ) 2 ) provides for further reaction and optionally (E) at least one binder soluble in water at room temperature.

Bevorzugte Brennstoffe (Komponente (A)) sind Nitroguanidin (NIGU), 5-Aminotetrazol (ATZ), Dicyandiamid (DCD), Dicyanamid, deren Salze, insbesondere Natrium- und Calciumdicyanamid und Guanidiniumnitrat, und deren Gemische. Diese sind praktisch ungiftig, nicht hygroskopisch, wenig wasserlöslich, thermisch stabil, bei niedriger Temperatur verbrennend und von geringer Schlag- und Reibempfindlichkeit. Die Gasausbeute bei der Verbrennung ist hoch, wobei ein großer Anteil an Stickstoffgas entsteht.Preferred fuels (component (A)) are nitroguanidine (NIGU), 5-aminotetrazole (ATZ), dicyandiamide (DCD), dicyanamide, their salts, especially sodium and calcium dicyanamide and guanidinium nitrate, and mixtures thereof. These are practically non-toxic, non-hygroscopic, poorly water-soluble, thermally stable, burning at a low temperature and of low impact and friction sensitivity. The combustion gas yield is high, producing a large amount of nitrogen gas.

Alkali- (Li, Na, K) und Erdalkalisalze (Mg, Ca, Sr, Ba) sind Beispiele für geeignete Salze von 5-Aminotetrazol.Alkali (Li, Na, K) and alkaline earth salts (Mg, Ca, Sr, Ba) are examples of suitable salts of 5-aminotetrazole.

Als Oxidationsmittel, Komponente (B), können Alkali- oder Erdalkalinitrate (wie Lithiumnitrat, Natriumnitrat, Kaliumnitrat, Magnesiumnitrat, Calciumnitrat, Strontiumnitrat oder Bariumnitrat), Ammoniumnitrat, Alkali- oder Erdalkalichlorate oder -perchlorate (wie Lithium-Natrium-, Kalium-, Magnesium-, Calcium-, Strontium- oder Bariumchlorat und Lithium-, Natrium-, Kalium-, Magnesium-, Calcium-, Strontium- oder Bariumperchlorat) sowie Ammoniumperchlorat und deren Gemische verwendet werden. Vorzugsweise wird Kaliumnitrat und Strontiumnitrat verwendet. Strontiumnitrat ist nicht hygroskopisch, nicht toxisch und ermöglicht beim Abbrand eine hohe Gasausbeute. Kaliumnitrat weist zusätzlich eine niedrige Abbrandtemperatur auf.As the oxidizing agent, component (B), alkali or alkaline earth nitrates (such as lithium nitrate, sodium nitrate, potassium nitrate, magnesium nitrate, calcium nitrate, strontium nitrate or barium nitrate), ammonium nitrate, alkali metal or alkaline earth chlorates or perchlorates (such as lithium, sodium, potassium, magnesium -, calcium, strontium or barium chlorate and lithium, sodium, potassium, magnesium, calcium, strontium or barium perchlorate) and ammonium perchlorate and mixtures thereof. Preferably, potassium nitrate and strontium nitrate are used. Strontium nitrate is non-hygroscopic, non-toxic and allows a high gas yield when burned. Potassium nitrate also has a low burning temperature.

Als hochschmelzende, im wesentlichen chemisch inerte Schlackenfänger, Komponente (C), werden Al2O3, TiO2 und ZrO2 in hochdisperser Form oder Gemische davon verwendet wobei Al2O3 eine BET-Oberfläche (in Anlehnung an DIN 66131) von 100 +/- 15 m2/g (Smp-Punkt ca. 2050°C), TiO2 eine BET-Oberfläche von 50 +/- 15 m2/g (Smp-Punkt ca. 1850°C) und ZrO2 eine/ BET-Oberfläche von 40 +/- 10 m2/g (Smp-Punkt ca. 2700°C) haben. Diese hochdispersen Oxide sind z.B. unter den Handelsnamen Aluminiumoxid C, Titanoxid P25 und VP Zirkonoxid (Degussa AG) im Handel erhältlich.Al 2 O 3 , TiO 2 and ZrO 2 in highly dispersed form or mixtures thereof are used as high-melting, substantially chemically inert slag scavengers, component (C) where Al 2 O 3 is a BET surface area (based on DIN 66131) of 100 +/- 15 m 2 / g (mp point about 2050 ° C), TiO 2 a BET surface area of 50 +/- 15 m 2 / g (mp point about 1850 ° C) and ZrO 2 a / BET surface area of 40 +/- 10 m 2 / g (mp point about 2700 ° C) have. These highly dispersed oxides are commercially available, for example, under the trade names aluminum oxide C, titanium oxide P25 and VP zirconium oxide (Degussa AG).

Diese pyrogenen Oxide werden durch Umsetzung der Metallchloride mit H2 und O2 im entsprechenden Molverhältnis durch Gasphasenreaktion (Flammenhydrolyse) hergestellt. Sie haben keine Poren und definierte Agglomerate, wie dies sonst bei der Herstellung im Naßverfahren der Fall ist.These pyrogenic oxides are prepared by reacting the metal chlorides with H 2 and O 2 in the appropriate molar ratio by gas phase reaction (flame hydrolysis). she have no pores and defined agglomerates, as is otherwise the case with the production in the wet process.

Unter Schlackenfänger (Komponente (C)) im Sinne der vorliegenden Erfindung versteht man hochschmelzende, im wesentlichen chemisch inerte Metalloxide in hochdisperser Form, d.h. diese Oxide weisen eine gegenüber den Oxiden in ihrer herkömmlichen Form sehr viel größere Oberfläche auf.For the purposes of the present invention, slag scavenger (component (C)) is understood to mean refractory, essentially chemically inert metal oxides in highly dispersed form, i. these oxides have a much larger surface area than the oxides in their conventional form.

Zum Beispiel weisen herkömmliches Al2O3 als α-Oxid eine BET-Oberfläche von nur 5-10 m2/g, herkömmliches Pigment-TiO2 eine BET-Oberfläche von nur 5-10 m2/g und herkömmliches ZrO2 eine BET-Oberfläche von nur 3-8 m2/g (für Feuerfest-Produkte) auf, wohingegen die in den Gasgeneratortreibsätzen der vorliegenden Erfindung verwendeten Metalloxide BET-Oberflächen von etwa 40 bis etwa 100 m2/g, besonders bevorzugt etwa 50 bis etwa 100 m2/g und insbesondere etwa 100 m2/g aufweisen.For example, conventional Al 2 O 3 as α-oxide has a BET surface area of only 5-10 m 2 / g, conventional pigment TiO 2 a BET surface area of only 5-10 m 2 / g, and conventional ZrO 2 a BET Surface area of only 3-8 m 2 / g (for refractory products), whereas the metal oxides used in the gas generator propellants of the present invention have BET surface areas of from about 40 to about 100 m 2 / g, more preferably from about 50 to about 100 m 2 / g and in particular about 100 m 2 / g.

Ferner zeichnen sich die Schlackenfänger der vorliegenden Erfindung durch ihren hohen Schmelzpunkt von etwa 1850 bis etwa 2700°C aus. Diese hohen Schmelzpunkte führen dazu, daß die Schlackenfänger während der Umsetzung nicht schmelzen und somit als Feststoffe fungieren.Furthermore, the slag scavengers of the present invention are characterized by their high melting point of about 1850 to about 2700 ° C from. These high melting points cause the slag scavengers not to melt during the reaction and thus act as solids.

Des weiteren handelt es sich bei den Schlackenfängern der vorliegenden Erfindung um im wesentlichen chemisch inerte Verbindungen, d.h. die Schlackenfänger der vorliegenden Erfindung beteiligen sich nicht bei der Verbrennungsreaktion der Gasgeneratortreibsätze an chemischen Umsetzungen oder nur in einem geringen Maß an der Oberfläche der als Schlackenfänger dienenden Metalloxide. Die hochaufgelösten Raumgitter, d.h. die große innere Oberfläche von z.B. Al2O3, TiO2 oder ZrO2 bewirkt einerseits durch ihre Inaktivität die Abkühlung der Verbrennungsprodukte und lagert andererseits speziell flüssige und/oder feste Schlackenteile bzw. Partikel an, die bei der Verbrennung entstehen. Auf diese Weise bleibt die Tablettenform, in der die Gasgeneratortreibsätze verwendet werden, während und nach dem Abbrand erhalten bzw. es lassen sich eventuell entstandene Bruchstücke leicht filtern. Das heißt, es bilden sich kaum Stäube, die bei der Verbrennung aus dem Gasgeneratortreibsatz und somit aus dem Gasgeneratorgehäuse austreten könnten. Die Schlackenfänger wirken somit als internes Filter in den Gasgeneratortreibsätzen selbst, und verhindern somit weitgehend die Entstehung und den Austritt von staubförmigen Schlackenteilen aus dem Gasgeneratorgehäuse, wodurch auch eine wesentliche Filtervereinfachung des Gasgeneratorgehäuses erreicht wird, da auf zusätzliche (mechanische) Feinfilter im Gasgeneratorgehäuse teilweise verzichtet werden kann. Dies führt auch zu einer vorteilhaften Gewichtseinsparung beim Airbag-Gasgenerator.Furthermore, the slag scavengers of the present invention are essentially chemically inert compounds, ie the slag scavengers of the present invention do not participate in the combustion reaction of the gas generator propellants to chemical reactions or only to a minor extent on the surface of the slag scavenger metal oxides. The high-resolution space lattice, ie the large inner surface of eg Al 2 O 3 , TiO 2 or ZrO 2 on the one hand causes by their inactivity, the cooling of the combustion products and stored on the other hand specially liquid and / or solid slag parts or particles that are formed during combustion , In this way, the tablet form, in which the gas generator propellant charges are used, is maintained during and after the burn-up, or it is possible to easily filter any resulting fragments. This means that hardly any dust forms, which could escape during combustion from the gas generator propellant charge and thus from the gas generator housing. The slag catchers work Thus, as an internal filter in the gas generator propellants themselves, and thus largely prevent the formation and the emergence of dusty slag parts from the gas generator housing, whereby a significant filter simplification of the gas generator housing is achieved because additional (mechanical) fine filter in the gas generator housing can be partially dispensed with. This also leads to an advantageous weight saving in the airbag inflator.

Gleichzeitig wird durch die Bildung von Schlacken das Entstehen von lungengängigen staubförmigen Anteilen vermindert, die aus dem Gasgenerator eines Airbags austreten könnten. Lungengängige staubförmige Teilchen haben einen Durchmesser von etwa 6 µm oder kleiner.At the same time, the formation of slag reduces the formation of respirable dust-like components which could escape from the gas generator of an airbag. Pulmonary dust-like particles have a diameter of about 6 μm or smaller.

Wahlweise können als Schlackenbildner, Komponente (D) Alkalimetall- und Erdalkalimetallcarbonate (wie Natriumcarbonat, Kaliumcarbonat, Magnesiumcarbonat, Calciumcarbonat, Strontiumcarbonat oder Bariumcarbonat), Alkalimetall- oder Erdalkalimetalloxide (wie Natrium-, Kalium-, Magnesium-, Calcium-, Strontium- oder Bariumoxid), Silikate (wie Hectorit), Aluminate (wie Natrium-beta-aluminat (Na2O11Al2O3) oder Tricalciumaluminat (Ca3Al2O6)) oder Aluminiumsilikate (wie Bentonite oder Zeolithe) oder Eisen(III)oxid oder deren Gemische verwendet werden.Optionally, as slag former, component (D), alkali metal and alkaline earth metal carbonates (such as sodium carbonate, potassium carbonate, magnesium carbonate, calcium carbonate, strontium carbonate or barium carbonate), alkali metal or alkaline earth metal oxides (such as sodium, potassium, magnesium, calcium, strontium or barium oxide ), Silicates (such as hectorite), aluminates (such as sodium beta-aluminate (Na 2 O 11 Al 2 O 3 ) or tricalcium aluminate (Ca 3 Al 2 O 6 )) or aluminum silicates (such as bentonites or zeolites) or iron (III) oxide or mixtures thereof are used.

Komponente (D) dient dazu, beim Abbrand des Gasgeneratortreibstoffs eine leicht filtrierbare Schlacke zu bilden.Component (D) serves to form an easily filterable slag during combustion of the gas generator fuel.

Die Schlackenbildner, Komponente (D), können zusätzlich noch als Kühlmittel wirken. Die Silikate, Aluminate und Aluminiumsilikate reagieren mit den Alkalimetall- und Erdalkalimetalloxiden, die beim Abbrand entstehen.The slag former, component (D), may additionally act as a coolant. The silicates, aluminates and aluminum silicates react with the alkali metal and Erdalkalimetalloxiden that arise during combustion.

Die Erfindung betrifft ferner die Verwendung von Katalysatoren auf der Basis von Platinmetallen (Ru, Os, Rh, Ir, Pd, Pt) oder Metallegierungen aus Platinmetallen oder Kupfer auf den hochdispersen Schlackenfängern als Träger, in den festen Gasgeneratortreibstoffen der vorliegenden Erfindung, insbesondere die Verwendung in festen Gasgeneratortreibsätzen für Airbags.The invention further relates to the use of catalysts based on platinum metals (Ru, Os, Rh, Ir, Pd, Pt) or metal alloys of platinum metals or copper on the highly dispersed slag scavenger carriers in the solid gas generator propellants of the present invention, in particular the use in fixed gas generator propellants for airbags.

Ein Teil des Schlackenfängers (Komponente (C)) kann als Träger dienen, auf dem ein Platinmetall oder eine Metallegierung aus Platinmetallen oder Kupfer in einer katalytisch wirksamen Schichtdicke aufgebracht ist.A part of the slag trap (component (C)) can serve as a carrier on which a platinum metal or a metal alloy of platinum metals or copper in a catalytically effective layer thickness is applied.

Platinmetalle sind Ruthenium (Ru), Osmium (Os), Rhodium (Rh), Iridium (Ir), Palladium (Pd) und Platin (Pt). Die Katalysatoren, die in der vorliegenden Erfindung verwendet werden, basieren vorzugsweise auf Rh, Pd oder Pt und insbesondere auf Pt.Platinum metals include ruthenium (Ru), osmium (Os), rhodium (Rh), iridium (Ir), palladium (Pd), and platinum (Pt). The catalysts used in the present invention are preferably based on Rh, Pd or Pt and in particular Pt.

Beispiele für Metallegierungen aus Platinmetallen sind alle katalytisch wirksamen Metallegierungen der vorstehend genannten Platinmetalle, vorzugsweise Pt/Pd- und Pt/Rh-Legierungen.Examples of metal alloys of platinum metals are all catalytically active metal alloys of the abovementioned platinum metals, preferably Pt / Pd and Pt / Rh alloys.

Die Metalle oder Metallegierungen aus Platinmetallen sind in einer katalytisch wirksamen Schichtdicke, vorzugsweise in einer einatomigen Schicht ("monolayer") auf dem Träger aufgebracht.The metals or metal alloys of platinum metals are applied in a catalytically active layer thickness, preferably in a monatomic layer ("monolayer") on the support.

Die Katalysatoren sind in nur katalytischen Mengen im Gasgeneratortreibsatz enthalten. Ihr Gewichtsanteil an der Komponente (C) beträgt 0,1-5 Gew.-%, vorzugsweise 0,2-1,2 Gew.-% der Komponente (C).The catalysts are contained in only catalytic amounts in the gas generator propellant. Their proportion by weight of the component (C) is 0.1-5 wt .-%, preferably 0.2-1.2 wt .-% of the component (C).

Bevorzugte Katalysatoren sind die, bei denen der hochdisperse Träger Al2O3 und das Metall Pt, Pd oder Cu, insbesondere Pt ist.Preferred catalysts are those in which the highly dispersed carrier is Al 2 O 3 and the metal is Pt, Pd or Cu, in particular Pt.

Geeignete Katalysatoren sind von der Degussa AG erhältlich, z.B. 1% Pt auf gamma-Al2O3 oder 1% Pd + Pt auf gamma-Al2O3.Suitable catalysts are available from Degussa AG, eg 1% Pt on gamma Al 2 O 3 or 1% Pd + Pt on gamma Al 2 O 3 .

Die Katalysatoren dienen dazu, die Reaktion dahingehend zu steuern, daß kaum toxische gasförmige Abbrandprodukte, wie Kohlenmonoxid (CO), Stickoxide (NOx) und Ammoniak (NH3) gebildet werden.The catalysts serve to control the reaction so that hardly toxic gaseous combustion products, such as carbon monoxide (CO), nitrogen oxides (NO x ) and ammonia (NH 3 ) are formed.

Die vorstehend genannten Katalysatoren sind besonders gut für die Verwendung in Gasgeneratortreibsätzen in Airbags geeignet.The above-mentioned catalysts are particularly well suited for use in gas generator propellants in airbags.

Zusätzlich zu den Vorteilen, die sich aus der Verwendung der hochdispersen Metalloxide ergeben (Verringerung der festen Staubteilchen, d.h. von Grob- und Feinstaub) wird hier der ohnehin geringe Anteil an toxischen Gasen weiter reduziert.In addition to the advantages resulting from the use of the fumed metal oxides (reduction of solid dust particles, i.e. coarse and fine dust), the already low level of toxic gases is further reduced here.

Die Katalysatoren können aus ausgelösten, d.h. gebrauchten Airbags, als auch aus nicht ausgelösten, d.h. aus Airbags aus Alt-Kraftfahrzeugen nach bereits bekannten Verfahren recycelt werden. Dies führt zu einer Abfallentlastung der Umwelt und ermöglicht die Wiederverwendung der Katalysatormetalle. Das Katalysatormetall bzw. die Metallegierung wird während des Abbrands nicht oxidiert.The catalysts may be triggered, i. used airbags, as well as from unreleased, i. be recycled from old-vehicle airbags according to previously known procedures. This leads to a waste relief of the environment and allows the reuse of the catalyst metals. The catalyst metal or the metal alloy is not oxidized during the burnup.

Der Katalysator muß nicht als zusätzlicher Bestandteil dem Gasgeneratortreibsatz zugesetzt werden, sondern der Katalysator ist Bestandteil einer ohnehin im Gasgeneratortreibsatz vorhandenen Komponente (Komponente C)).The catalyst need not be added as an additional component to the gas generator propellant, but the catalyst is part of an already present in the gas generator propellant component (component C)).

Komponente (A) liegt in einer Menge von etwa 20 bis 60 Gew.-%, vorzugsweise von etwa 28 bis 52 Gew.-% und insbesondere von etwa 45 bis 51 Gew.-% vor, Komponente (B) in einer Menge von etwa 38 bis etwa 63 Gew.-%, vorzugsweise von etwa 38 bis etwa 55 Gew.-% und insbesondere von etwa 39 bis 45 Gew.-% vor, Komponente (C) in einer Menge von etwa 5 bis 22 Gew.-%, vorzugsweise von etwa 8 bis 20 Gew.-% und insbesondere von etwa 9 bis 11 Gew.-% und Komponente (D), sofern enthalten, in einer Menge von etwa 2 bis 12 Gew.-%, vorzugsweise von etwa 4 bis 10 Gew.-% vor, jeweils bezogen auf die Gesamtzusammensetzung des Gasgeneratortreibsatzes.Component (A) is present in an amount of from about 20 to 60% by weight, preferably from about 28 to 52% by weight and in particular from about 45 to 51% by weight, component (B) in an amount of about 38 to about 63 wt .-%, preferably from about 38 to about 55 wt .-% and in particular from about 39 to 45 wt .-% before, component (C) in an amount of about 5 to 22 wt .-%, preferably from about 8 to 20% by weight and in particular from about 9 to 11% by weight and component (D), if present, in an amount of about 2 to 12% by weight, preferably from about 4 to 10% by weight .-% before, in each case based on the total composition of the gas generator propellant.

Wahlweise kann der Gasgeneratortreibstoff ferner als Komponente (E) ein in Wasser bei Raumtemperatur lösliches Bindemittel enthalten. Bevorzugte Bindemittel sind Celluloseverbindungen oder Polymerisate aus einem oder mehreren polymerisierbaren olefinisch ungesättigten Monomeren. Beispiele für Celluloseverbindungen sind Celluloseether, wie Carboxymethylcellulose, Methylcelluloseether, insbesondere Methylhydroxyethylcellulose. Eine gut verwendbare Methylhydroxyethylcellulose ist CULMINAL® MHEC 30000 PR der Firma Aqualon. Geeignete Polymerisate mit Bindewirkung sind Polyvinylpyrrolidon, Polyvinylacetat, Polyvinylalkohol und Polyvinylbutyral, z.B. Pioloform® B (Firma Wacker Chemie, Burghausen).Optionally, the gas generator fuel may further contain as component (E) a water-soluble binder at room temperature. Preferred binders are cellulose compounds or polymers of one or more polymerizable olefinically unsaturated monomers. Examples of cellulose compounds are cellulose ethers, such as carboxymethylcellulose, methylcellulose ethers, in particular methylhydroxyethylcellulose. A good usable methylhydroxyethylcellulose is CULMINAL® MHEC 30000 PR from Aqualon. Suitable polymers having a binding effect are polyvinylpyrrolidone, polyvinyl acetate, Polyvinyl alcohol and polyvinyl butyral, eg Pioloform® B (Wacker Chemie, Burghausen).

Als Bindemittel, Komponente (E), kann auch ein in Wasser bei Raumtemperatur unlösliches Metallsalz der Stearinsäure, wie Aluminiumstearat, Magnesiumstearat, Calciumstearat oder Zinkstearat verwendet werden.As the binder, component (E), a metal salt of stearic acid insoluble in water at room temperature, such as aluminum stearate, magnesium stearate, calcium stearate or zinc stearate, may also be used.

Graphit ist ebenfalls als Bindemittel geeignet.Graphite is also suitable as a binder.

Komponente (E) liegt in einer Menge von 0 bis 2 Gew.-% und vorzugsweise von 0,3-0,8 Gew.-% vor.Component (E) is present in an amount of from 0 to 2% by weight, and preferably from 0.3 to 0.8% by weight.

Das Bindemittel, Komponente (E), dient als Desensibilisierungsmittel und als Verarbeitungshilfe bei der Herstellung von Granulat oder Tabletten (Pellets) aus dem Gasgeneratortreibstoff. Es dient ferner zur Verminderung der Hydrophilie und zur Stabilisierung der Gasgeneratortreibsätze.The binder, component (E), serves as a desensitizer and as a processing aid in the production of granules or pellets from the gas generator fuel. It also serves to reduce the hydrophilicity and to stabilize the gas generator propellant charges.

Herstellungsvorschrift:Preparation Method:

Allgemein erfolgte die Herstellung der Gasgeneratortreibstoffe (Beispiele 1 bis 57 der nachstehenden Tabelle I) und Gasgeneratortreibsätze nach folgendem Vorgehen:Generally, the gas generant fuels (Examples 1 to 57 of Table I below) and gas generator propellants were prepared according to the following procedure:

Die grob vorgemischten Rohstoffe (Komponenten (A), (B), (C) und gegebenenfalls (D) und (E)) wurden mittels einer Kugelmühle gemahlen bzw. vorverdichtet.
Das Granulieren der Gasgeneratortreibstoffmischung erfolgte in einem Vertikalmischer durch Zugabe von ca. 20 % Wasser beim Rühren und bei einer auf ca. 40°C erhöhten Temperatur.
Nach kurzem Ablüften wurde die erhaltene Mischmasse bei Raumtemperatur durch eine Durchreibemaschine mit einem 1 mm-Sieb gerieben. Das auf diese Weise erhaltene Granulat wurde ca. 2 Stunden in einem Trockenofen bei 80°C getrocknet.
Das fertige Granulat des Gasgeneratortreibstoffes (Kornverteilung 0-1 mm) wurde anschließend mit einer Rundläuferpresse zu Tabletten (Pellets) verpreßt. Diese Gasgeneratortreibsatzpellets wurden bei 80°C im Trockenofen nachgetrocknet.The roughly premixed raw materials (components (A), (B), (C) and optionally (D) and (E)) were ground or precompressed by means of a ball mill.
The granulation of the gas generator fuel mixture was carried out in a vertical mixer by adding about 20% water while stirring and at a temperature increased to about 40 ° C.
After brief flash-off, the resulting blend was rubbed at room temperature through a 1 mm screen through-hole machine. The granules thus obtained were dried for about 2 hours in a drying oven at 80 ° C.
The finished granulate of the gas generator fuel (particle size distribution 0-1 mm) was then pressed into tablets (pellets) using a rotary press. These gas generator propellant pellets were post-dried at 80 ° C in a drying oven.

Die in den Gasgeneratoren verwendeten Tabletten oder Pellets aus dem Gasgeneratortreibstoff können nach bekannten Verfahren hergestellt werden, etwa durch Strangpressen, Extrudieren, in Rundläuferpressen oder Tablettiermaschinen. Die Größe der Pellets oder Tabletten hängt von der gewünschten Brennzeit im jeweiligen Anwendungsfall ab.The tablets or pellets from the gas generator fuel used in the gas generators can be prepared by known methods, such as extruding, extruding, in rotary presses or tableting machines. The size of the pellets or tablets depends on the desired firing time in the particular application.

Der erfindungsgemäße Gasgeneratortreibstoff besteht aus nicht-toxischen, leicht herstellbaren und kostengünstigen Komponenten, deren Verarbeitung unproblematisch ist. Die Komponente, die weniger kostengünstig ist, nämlich das Katalysatormetall, kann nach bekannten Verfahren recycelt werden. Die thermische Stabilität der Komponenten bewirkt eine gute Lagerfähigkeit. Die Anzündbarkeit der Gemische ist gut. Sie brennen schnell und liefern große Gasausbeuten mit sehr geringen CO-, NOx- und NH3-Anteilen, die unterhalb der zulässigen Höchstgrenze liegen. Die erfindungsgemäßen Gemische sind daher zur Verwendung als Gaserzeugungsmittel in den verschiedenen Airbag-Systemen, als Löschmittel oder Treibmittel besonders geeignet.The gas generator fuel of the invention consists of non-toxic, easy to produce and inexpensive components whose processing is straightforward. The less cost-effective component, namely, the catalyst metal, can be recycled by known methods. The thermal stability of the components causes a good shelf life. The ignitability of the mixtures is good. They burn quickly and deliver high gas yields with very low CO, NO x and NH 3 levels below the allowable limit. The mixtures according to the invention are therefore particularly suitable for use as gas generants in the various airbag systems, as extinguishing agents or propellants.

Die nachstehenden Beispiele 1 bis 57 veranschaulichen die Erfindung, schränken diese jedoch nicht ein. Bei den Beispielen 15, 18 und 21 handelt es sich um Vergleichsbeispiele, bei denen herkömmliches ZrO2, TiO2 und Al2O3 verwendet wurde. Tabelle I: Die in der Tabelle angegebenen Indizes haben folgende Bedeutung: 1 Titandioxid P25, Degussa AG 2 Zirkonoxid VP, Degussa AG 3 Aluminiumoxid C, Degussa AG 4 Titandioxid Kronos 3025, Kronos Titan-GmbH 5 Zirkonoxid, Merck 6 Aluminiumoxid NO 615-30 II 24, Nabaltec 7 Oxid. Katalysator 1 % Pt auf Gamma-Aluminiumoxid, Degussa AG 8 Oxid. Katalysator 1% Pd + Pt auf Gamma-Aluminiumoxid, Degussa AG 9 Eisenoxid, Bayoxide E8710, Bayer AG 10 Bentone EW, Rheox, Inc. 11 CULMINAL MHEC 30000 PR, Aqualon

Figure imgb0001
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 Examples 1 to 57 below illustrate the invention, but do not limit it. Examples 15, 18 and 21 are comparative examples using conventional ZrO 2 , TiO 2 and Al 2 O 3 . <u> Table I: </ u> The indexes specified in the table have the following meaning: 1 Titanium Dioxide P25, Degussa AG 2 Zirconium oxide VP, Degussa AG 3 Alumina C, Degussa AG 4 Titanium dioxide Kronos 3025, Kronos Titan GmbH 5 Zirconia, Merck 6 Alumina NO 615-30 II 24, Nabaltec 7 Oxide. Catalyst 1% Pt on gamma-alumina, Degussa AG 8th Oxide. Catalyst 1% Pd + Pt on gamma-alumina, Degussa AG 9 Iron oxide, Bayoxide E8710, Bayer AG 10 Bentone EW, Rheox, Inc. 11 CULMINAL MHEC 30000 PR, Aqualon
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Die Abbrände wurden in einem praxisnahen Gasgeneratorgehäuse für den 60 Liter Fahrer-Airbag durchgeführt, mit Originalabmessungen, -anzünder und Filterpaket aus Edelstahl.The burn-offs were carried out in a practical gas generator housing for the 60-liter driver's airbag, with original dimensions, lighters and filter pack made of stainless steel.

Das eingesetzte Gasgeneratortreibsatzgewicht betrug 50 bis 55 g, je nach Gasausbeute der jeweiligen Gasgeneratortreibstoff-Rezeptur.The gas generator propellant weight used was 50 to 55 g, depending on the gas yield of the respective gas generator fuel formulation.

Die Pellets hatten je nach Abbrandeigenschaften einen Durchmesser von 4 bis 6 mm, bei einer Pellethöhe von 1,5 bzw. 2,1 mm.Depending on the burning properties, the pellets had a diameter of 4 to 6 mm, with a pellet height of 1.5 or 2.1 mm.

Die Gasausbeute und die Temperatur liegt im für Gasgeneratortreibstoffe für Airbags günstigen Bereich.Gas yield and temperature are within the range favorable for gas generator propellants for airbags.

Bei der Angabe "Grobstaub" und "Feinstaub" in der Tabelle handelt es sich um den Schmutz in der Kanne nach der Verbrennung.The words "Coarse dust" and "Fine dust" in the table are the dirt in the pot after combustion.

Die in der vorstehenden Tabelle angegebenen gemessenen Werte für CO, NOx und NH3 beziehen sich auf eine 60 Liter-Kanne. Hierbei handelt es sich um gute Werte für einen nicht optimierten Versuchsgasgenerator.The measured values for CO, NO x and NH 3 given in the table above refer to a 60 liter can. These are good values for a non-optimized experimental gas generator.

Aus dem Vergleich der Beispiele 14 mit 15, 17 mit 18 und 20 mit 21 ist der Effekt der hochdispersen Oxide im Vergleich zu den herkömmlichen Oxiden ersichtlich. Die Verringerung des Partikelausstoßes (Grob -und Feinstaub) betrug bei dem System Nitroguanidin/ Strontiumnitrat aufgrund der speziellen, erfindungsgemäß verwendeten hochdispersen Schlackenfänger (C) ca. 20 bis 40% im Vergleich zu den herkömmlichen Oxiden gleicher chemischer Strukturformel, aber geringerer spezifischer Oberfläche. Ebenfalls ersichtlich ist die Verringerung der toxischen Gasanteile um ca. 10 bis 25% bedingt durch die Verbesserung der Verbrennung aufgrund der speziellen, erfindungsgemäß verwendeten Schlackenfänger (C) und deren Eigenschaften.From the comparison of Examples 14 with 15, 17 with 18 and 20 with 21, the effect of the fumed oxides in comparison to the conventional oxides can be seen. The reduction of particle emissions (coarse and fine dust) in the system nitroguanidine / strontium nitrate was about 20 to 40% compared to the conventional oxides of the same chemical structural formula, but lower specific surface area due to the special highly disperse slag scavenger (C) used in the invention. Also visible is the reduction of the toxic gas components by about 10 to 25% due to the improvement of the combustion due to the particular slag traps (C) used in the invention and their properties.

Weiterhin ist aus dem Vergleich, z.B. der Gasgeneratortreibstoffe der Beispiele 2 mit 8 und 10 der zusätzliche günstige Effekt bei der Verwendung von mit Katalysatoren dotierten hochdispersen Schlackenfängern (C) auf die Bildung von toxischen Gasanteilen ersichtlich.Furthermore, from the comparison, for example the gas generator propellants of Examples 2 with 8 and 10, the additional favorable effect of using catalyst-doped highly dispersed slag scavengers (C) on the formation of toxic gas components can be seen.

Der Anteil an CO und NOx liegt bei den Beispielen 8 und 10 (mit Katalysator) unter den in Beispiel 2 (ohne Katalysator, aber ansonsten mit gleicher Zusammensetzung) angegebenen Werte.The amounts of CO and NO x in Examples 8 and 10 (with catalyst) are below the values given in Example 2 (without catalyst, but otherwise with the same composition).

Besonders bevorzugte Zusammensetzungen sind die der Beispiele 14, 17 und 20.Particularly preferred compositions are those of Examples 14, 17 and 20.

Die thermodynamischen Daten der einzelnen Gasrezepturen wurden auf den Sauerstoffbilanzüberschuß hin berechnet, der möglichst wenig toxische Gasentwicklung beim Abbrand versprach.The thermodynamic data of the individual gas formulations were calculated on the oxygen balance surplus, which promised the least possible toxic gas evolution during combustion.

Claims (16)

  1. Propellant for gas generators, comprising
    (A) at least one fuel selected from the group consisting of guanidine nitrate (GUNI; GuNO3), dicyanamide, ammonium dicyanamide, sodium dicyanamide (Na-DCA), copper dicyanamide, tin dicyanamide, calcium dicyanamide (Ca-DCA), guanidine dicyanamide (GDCA), aminoguanidine bicarbonate (AGB), aminoguanidine nitrate (AGN), triaminoguanidine nitrate (TAGN), nitroguanidine (NIGU), dicyandiamide (DCD), azodicarbonamide (ADCA) as well as tetrazole (HTZ), 5-aminotetrazole (ATZ), 5-nitro-1,2,4-triazole-3-on (NTO), salts and mixtures thereof,
    (B) at least one alkali metal nitrate or alkaline earth metal nitrate or ammonium nitrate, -chlorate or -perchlorate,
    (C) at least one essentially chemically-inert slag trap which has been prepared by flame hydrolysis and which has a high melting point, selected from the group consisting of highly dispersed Al2O3 having a specific surface of 100 +/-15 m2/g, highly dispersed TiO2 having a specific surface of 50 +/- 15 m2/g and highly dispersed ZrO2 having a specific surface of 40 +/- 10 m2/g and mixtures thereof.
  2. Propellant for gas generators according to claim 1, wherein component (A) is present in an amount of about 20 to 60 wt.-%, preferably of about 28 to 52 wt.-% and in particular of about 45 to 51 wt.-%, component (B) is present in an amount of about 38 to about 63 wt.-%, preferably of about 38 to about 55 wt.-% and in particular of about 39 to 45 wt.-%, component (C) is present in an amount of about 5 to 22 wt.-%, preferably of about 8 to 20 wt.-% and in particular of about 9 to 11 wt.-%.
  3. Propellant for gas generators according to claim 1 or 2, wherein component (A) is selected from the group consisting of nitroguanidine, 5-aminotetrazole, dicyandiamide, dicyanamide, sodium- and calcium dicyanamide and guanidine nitrate, and mixtures thereof.
  4. Propellant for gas generators according to any one of claims 1 to 3, wherein component (B) is selected from the group consisting of sodium-, potassium- and strontium nitrate.
  5. Propellant for gas generators according to any one of claims 1 to 4, wherein a part of the component (C) serves as a carrier for a platinum metal or a metal alloy of platinum metals or copper in a catalytically effective layer thickness.
  6. Propellant for gas generators according to claim 5, wherein the platinum metal is selected from ruthenium (Ru), Osmium (Os), rhodium (Rh), iridium (Ir), palladium (Pd) and platinum (Pt).
  7. Propellant for gas generators according to claim 5, wherein the metal alloy of platinum metals is selected from Pt/Pd and Pt/Rh alloys.
  8. Propellant for gas generators according to any one of claims 5 to 7, wherein the weight portion of the catalyst with respect to component (C) is 0.1 to 5 wt.-%, preferably 0.2 to 1.2 wt.-%.
  9. Propellant for gas generators according to any one of claims 1 to 8, wherein component (A) is nitroguanidine, component (B) is strontium nitrate and component (C) is highly dispersed Al2O3, TiO2 or ZrO2.
  10. Propellant for gas generators according to claim 9, wherein component (A) is present in an amount of 45 to 51 wt.-%, component (B) is present in an amount of 39 to 45 wt.-% and component (C) is present in an amount of 9 to 11 wt.-%, with respect to the total composition.
  11. Propellant for gas generators according to any one of claims 1 to 9, wherein at least one slag former, selected from alkali metal and alkaline earth metal carbonates, alkali metal and alkaline earth metal oxides, silicates, aluminates, aluminium silicates, silicon nitride (Si3N4) and iron(III)oxide is additionally present as component (D).
  12. Propellant for gas generators according to claim 11, wherein component (D) is present in an amount of about 2 to 12 wt.-%, preferably in an amount of about 4 to 10 wt.-%.
  13. Propellant for gas generators according to any one of claims 1 to 12, further containing component (E) at least one binder being soluble in water at room temperature.
  14. Propellant for gas generators according to claim 13, wherein the binder is selected from the group consisting of cellulose compounds, polymers of one or more polymerisable olefinically unsaturated monomers, a metal salt of stearic acid being insoluble in water at room temperature and graphite.
  15. Propellant for gas generators according to claim 13 or 14, wherein the binder is present in an amount of 0 to 2 wt.-%, preferably of 0.3 to 0.8 wt.-%.
  16. Use of the propellant for gas generators according to any one of claims 1 to 15 as gas-generating agent in airbags, as extinguishing agent or as propellant.
EP99919100A 1998-03-20 1999-03-17 Propellants for gas generator Expired - Lifetime EP1064242B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE19812372 1998-03-20
DE19812372A DE19812372C2 (en) 1998-03-20 1998-03-20 Gas generator fuels
PCT/DE1999/000782 WO1999048843A1 (en) 1998-03-20 1999-03-17 Propellants for gas generator

Publications (2)

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EP1064242A1 EP1064242A1 (en) 2001-01-03
EP1064242B1 true EP1064242B1 (en) 2006-10-11

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EP99919100A Expired - Lifetime EP1064242B1 (en) 1998-03-20 1999-03-17 Propellants for gas generator

Country Status (8)

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EP (1) EP1064242B1 (en)
JP (1) JP2002507542A (en)
KR (1) KR20010041919A (en)
AT (1) ATE342246T1 (en)
AU (1) AU3699999A (en)
CZ (1) CZ297313B6 (en)
DE (2) DE19812372C2 (en)
WO (1) WO1999048843A1 (en)

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CZ301335B6 (en) * 2005-06-15 2010-01-20 Explosia, A. S. Pyrotechnical compositions for safety belt pre-tensioning devices
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JP6231876B2 (en) * 2013-12-27 2017-11-15 日本工機株式会社 Aerosol fire extinguishing device for moving body and aerosol fire extinguishing agent used therefor
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CZ20003417A3 (en) 2001-02-14
AU3699999A (en) 1999-10-18
ATE342246T1 (en) 2006-11-15
DE19812372C2 (en) 2001-10-04
KR20010041919A (en) 2001-05-25
DE59913910D1 (en) 2006-11-23
EP1064242A1 (en) 2001-01-03
JP2002507542A (en) 2002-03-12
CZ297313B6 (en) 2006-11-15
DE19812372A1 (en) 1999-09-30
WO1999048843A1 (en) 1999-09-30

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