FI127822B - Oxidation agent for a composition that produces gas in a vehicle's safety device, composition for producing gas, and gas generator for a vehicle's safety device - Google Patents

Abstract

The invention relates to an oxidizing agent for a composition which produces gas, especially in a vehicle's safety device, which oxidizing agent comprises ammonium nitrate. As mentioned, ammonium nitrate is an oxidizing agent in powder form. In addition, as mentioned oxidant, ammonium nitrate is ammonium nitrate without additives to stabilize ammonium nitrate against degradation caused by temperature changes, in a gas-producing composition. The invention further relates to a composition for the production of gas and a gas generator for a vehicle safety device.

Description

OXIDIZER FOR A GAS-PRODUCING COMPOSITION IN A VEHICLE SECURITY DEVICE, A GAS PRODUCTION COMPOSITION AND A GAS GENERATION— Rl FOR A VEHICLE SAFETY DEVICE

The present invention relates to an oxidizing agent for a gas producing composition in a vehicle safety device, which oxidizing agent comprises ammonium nitrate, said oxidizing agent being in powder form. In addition, the invention also relates to a composition for producing gas, a gas generator for a vehicle security device, and uses of an oxidizing agent and composition.

Safety equipment used in the automotive industry has encountered problems with the explosion of airbags based on ammonium nitrate explosives. As a result, at least a dozen people have died and more than a hundred have been injured. Several airbags have triggered more than intended in the event of an accident. As a result, the metal parts of the device are fragmented and flown towards the driver or passenger. As a result, car manufacturers have already called in over 100 million cars for repair, and the trend is that the number of recalls will continue to grow. This may be the biggest and most complex consumer health issue in industrial history.

The above problem would appear to be caused by the deterioration of ammonium nitrate used in vehicle airbag inflators due to repeated temperature fluctuations. As a result of weathering, the particle size, porosity and specific surface area of the ammonium nitrate increase, causing an increase in the detonation rate, or explosion force, of the ammonium nitrate-based explosive. Ammonium nitrate undergoes several phase transitions during heating and cooling, in which its crystal structure and volume change. Figure 1 shows a classic plot of the volume change caused by ammonium nitrate phase transitions as a function of temperature.

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In phase transitions, ammonium nitrate may decay when its physical form is destroyed. In most common inflationers, ammonium nitrate-based explosives are granulated, for example, in tablet or disk form.

The interior temperature of cars in the United States, for example, can easily be between 0 and +80 ° C. At these temperatures, ammonium nitrate undergoes transitions between phases IV, III and II. Each transition breaks the structure of the ammonium nitrate tablets.

In industry, the general approach has been to try to stabilize ammonium nitrate so that the above transitions do not occur. Phase-stabilized ammonium nitrate (PSAN) is generally referred to as the phase stabilized ammonium nitrate. It is characterized by the fact that it has been attempted to use it with various additives so that it does not undergo any of the phase transitions described above at any desired temperature range. An example of such an additive is potassium nitrate. In this case, ammonium nitrate and potassium nitrate are used as the double salt. In it, the ammonium, potassium and nitrate ions are alternately in the same crystal lattice.

However, some of the problems with potassium nitrate are the small amount of stabilization effect it produces and, in addition, particle formation in the explosion. More generally, significant amounts of additives have to be used, but still they have not achieved sufficient stability of ammonium nitrate against the weathering effect caused by temperature changes. Some of the additives are also toxic and difficult to recycle and also expensive.

There are many reasons for using ammonium nitrate, for example, in car airbags and equipment. For example, ammonium nitrate would be more environmentally friendly and easier to recycle. In addition, the ammonium nitrate mer

20185160 prh 02 -01-20199 The most significant benefit over alternative explosive components used in airbags, such as sodium azide, is its low cost, easy availability and minor health effects (eg carcinogen-free and non-toxic5) when the substance is potentially exposed to the human body. However, the abovementioned problems of weathering have made the use of ammonium nitrate difficult and expensive precisely because of their additives and the poor stability achieved by them.

As prior art, reference is made to the following patents: US 2010109304 A1, US 2014150935 A1, GB 1215681 A and US 5516377 A.

It is an object of the present invention to provide an oxidizing agent for a gas-producing composition, in particular a vehicle safety device, which is stable in its properties so that its detonation properties are not altered as a result of thermal cycles. In addition, the invention also relates to a composition for producing gas and a gas generator for a vehicle security device. Characteristic features of the oxidizing agent of the invention are set forth in claim 1, the composition claim 6 and the gas generator claim 10.

The ammonium nitrate contained in the oxidizing agent is in powder form and in addition ammonium nitrate as an oxidizing agent to stabilize the ammonium nitrate in the gas producing composition against the deterioration of the ammonium nitrate caused by temperature changes. As the powdery bulk material, i.e. the non-granulated material, the degradation of ammonium nitrate and the composition containing it is less so that its particle size and / or specific surface area do not change when exposed to temperature variations. This will maintain the properties of ammonium nitrate better.

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The oxidizing agent of the invention provides a more stabilized oxidizing agent and thus a more standardized and also predictable reaction, such as an explosion or gas production, against weathering. In other words, the ammonium nitrate used as the oxidizing agent is stable so that its detonation properties do not change as a result of thermal cycles in the application of the ammonium nitrate. Ammonium nitrate used as an oxidizing agent is a powdery fines, that is, non-granulated. In that case, its pairs of) the size of the chips are not substantially reduced (or increased) and the specific surface area does not increase as a result of thermal cycles. As a result, its detonation rate remains essentially constant regardless of the temperature variations it experiences as an oxidizing agent in the composition. With the Kek15 invention, the ammonium nitrate material undergoes thermal cycling as an oxidizing agent without deterioration or friability, and its particle size and / or specific surface area do not substantially change as an oxidizing agent in thermal cycles.

The ammonium nitrate used as the oxidizing agent may have a particle size of 0.5 to 1000 µm. In this case, it is very finely divided and, as a result of temperature fluctuations, no longer decomposes into smaller particles. It then reacts, for example, to explode or to produce gas, with the same force, irrespective of, for example, temperature variations in storage and / or actuation of the oxidizing agent or composition containing it.

The ammonium nitrate-based oxidant according to the invention achieves the same relatively low burning rates and less aggressive nature required in safety devices, as does, for example, phase-stabilized ammonium nitrate (PSAN) according to the prior art.

The ammonium nitrate of the invention, more generally oxidizing agent 35, also has a homogeneous non-granulated composition and

20185160 prh 02 -01- 2019 ni moisture absorption. Its combustion gases are non-toxic.

Nor is it or its combustion products harmful to the environment throughout its life cycle. In addition, the associated energy consumption is low throughout its life cycle.

The use of the oxidizing agent in the safety devices is low with the invention and its cost is low. The oxidizing agent of the invention may also fulfill one of the major properties required of explosive gas generator explosives, which is to form as little or preferably no solid combustion products as possible. With the invention, the combustion products need not be filtered.

This simplifies the technical implementation of gas generators and safety devices. Filters are always problematic because of the risk of clogging.

According to one embodiment, the particle size suitable for the ammonium nitrate can be obtained by at least one of the following processes: thermal cycling, grinding, recrystallization, steam crystallization and / or atomization. For example, by thermal cyclisation of 20 solid ammonium nitrate over a temperature range of -30 ° C to + 100 ° C, the particle size of the ammonium nitrate can be controlled and small crystalline and porous materials can be produced to achieve high detonation rate and physical structural stability.

Through the invention, ammonium nitrate behaves in an explosive or gas-producing manner in the same predictable manner, no matter what kind of temperature change it has experienced in its application. In this case, it can be dispensed to the product less than in the prior art. The ammonium nitrate used as the oxidizing agent 30 is not compressed or, more generally, granulated according to the prior art, but is used as an oxidizing agent in powder form, and thus un granulated, or depending on other components of the explosive, for example paste. More generally, one can talk about bulk material.

Other additional advantages achieved by the invention will be apparent from the description and the features of the appended claims.

The invention, which is not limited to the following embodiments, will be described in more detail below.

Figure 1

Fig. 2 shows a classical plot of the volume change caused by ammonium nitrate phase transitions as a function of temperature and illustrates an embodiment of a system in which the ammonium nitrate of the invention can be utilized as an oxidizing agent.

The oxidizing agent for the vehicle gas-producing composition of the special safety device, and more particularly, its gas generator includes ammonium nitrate (NENCg). Ammonium nitrate i is in powder form as an oxidizing agent. In addition, ammonium nitrate i is an oxidizing agent without additives to stabilize the ammonium nitrate in the gas-producing composition against weathering caused by temperature changes. Degradation occurs particularly in ammonium nitrate and thus also in the composition in which it is used.

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The Applicant has found in his pilot tests that it is possible to use ammonium nitrate 25 with a better physical stability and thus a better detonation properties and thus as the main unchanged oxidizing agent, for example in a gas producing composition when the ammonium nitrate is in powder form. This improves the structural stability of the ammonium nitrate in the application, despite any temperature changes that may occur therein. In its powdered form, ammonium nitrate is in the form of a fines, that is, non-granulated. Thus, the composition comprising it, or the composition comprising it, is not compressed into pellets, granules, granules or tablets, formed into glasses or other resistive structures which are structural units.

instead, the only one that is sensitive to ammonia nitrate from ammonium nitrate can be brought to the desired solids unit. For example, as units, the surface area and thus the detergents may change as a result of variations; in addition to forming bulk material in the form of pellets, ammonium nitrate also ammonium nitrate is unpredictable, that is, more generally from bulk material or granular material. Similarly, a composition in which ammonium nitrate is present may be referred to as such.

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According to one embodiment, the ammonium nitrate has a particle size of 0.5 to 1000 µm in powder form as an oxidizing agent. For example, particle size 20 refers to the smallest dimension of the particle. For example, in the case of an elongated crystal, the particle size may be considered to be a crystal diameter less than its length. The particle size may be determined, for example, by screening or by a particle size analyzer. Materials having different particle sizes can also be compared by their density by measuring the mass of the samples relative to their volume pressed at a low constant pressure.

As the particle size decreases, the specific surface area of the material increases, which also increases the explosion rate. When the particle size is small enough, it has been observed to obtain a material whose explosive strength is no longer affected by temperature variations. The amounts of ammonium nitrate used in the invention can be reduced. The same explosive force is achieved with a lower mass 35, whereby the explosive force with respect to the explosive mass increases.

However, the amount of gas formed relative to the mass of the explosive remains the same.

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The powdered ammonium nitrate, preferably having the aforementioned particle size, is more stable than the ammonium nitrate oxidant produced by the methods currently in use, and is therefore safe for use in airbag applications, for example, under actual temperature conditions. In particular, with the invention, ammonium nitrate is more stable to weathering, i.e. has a more stable physical structure. However, ammonium nitrate can still experience its characteristic phase changes in temperature fluctuations, but its structure does not substantially change with the invention, and the above-mentioned properties, namely non-deterioration and retention of detonation properties, are achieved. Pilot-phase tests have also found that the density of the ammonium nitrate of the invention as an oxidizing agent may be below the known density of ammonium nitrate for which values in the literature range from 1.327 to 1.71 g / cm ³ . On the basis of the observation made by the applicant in the pilot phase tests, the volume of unpressed ammonium nitrate of the invention in the blasting tube was estimated to be about 2.5 times higher than the known technical grades, i.e. the density would then be correspondingly lower.

The stabilization of ammonium nitrate against weathering is achieved by processing ammonium nitrate such that the processed ammonium nitrate is essentially pure ammonium nitrate as an oxidizing agent, in the absence of additives to stabilize am30 monium nitrate in the gas producing composition against weathering. In other words, ammonium nitrate is then a pure substance in the sense that its lattice structure contains no ions other than ammonium and nitrate ions. That is, its lattice structure has no other specifically

20185160 prh 02 -01-20199 for stabilization of ammonium nitrate against weathering additives.

For example, ammonium nitrate for use as an oxidizing agent in a gas producing composition can be prepared by any technique known per se in the art.

Ammonium nitrate is water soluble, which makes it difficult to avoid the use of difficult solvents in the ammonium nitrate production process. Ammonium nitrate can be processed or prepared by one or more treatment methods in order to obtain a small particle size size which is more resistant to weathering and thus to a suitable specific surface area in ammonium nitrate without additives. According to one embodiment, substantially non-corrosive ammonium nitrate having a suitable particle size and specific surface area without additives for stabilizing the ammonium nitrate in the gas-producing composition against ammonium nitrate decomposition due to temperature changes can be achieved by one or more processes of höyrykiteytys.

In the manufacturing step, the thermal cyclisation of ammonium nitrate can be carried out, for example, by first letting the ammonium nitrate in the set manner and then cooling it in the set way. Heating and also cooling can be done step by step. The steps can be formed, for example, on the basis of ammonium nitrate phase transitions. Heating and cooling can be carried out, for example, at temperatures between -30 and +107 ° C, i.e. between V-II ammonium nitrate. According to one embodiment, the heating and cooling temperature range is subdivided and the material is held at these temperatures for a set amount of time during cooling or heating before changing the temperature in the next step. The thermal cycling10 is continued with the necessary amount of cycles. The amount is determined from experiments.

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Specifically, the thermal cyclisation of ammonium nitrate can be sought to occur through phase III, i.e., a temperature range of +32 +84 ° C. Phase III thermal cycling has the advantage that the ammonium nitrate is then subjected to more severe treatment. The treatment then breaks the crystalline structures of ammonium nitrate, which promotes the attainment of a suitable particle size and a specific surface area.

When sufficient cycles of heat treatment have been performed, ammonium nitrate is obtained in a more stable form against weathering. Thereafter, the detonation properties of ammonium nitrate15 will not change substantially, even if subjected to new temperature changes, such as may occur in safety devices in vehicles, but will, for example, be standardized with sufficient detonation properties.

The milling of ammonium nitrate can be carried out, for example, by sufficiently milling the ammonium nitrate, such as in the form of mm-sized granules. Grinding by this method is carried out until the desired particle size is achieved. For this purpose, the material to be milled is sampled and formed to form a rule for a suitable milling time and method. After milling, the milled ammonium nitrate is sieved.

The spraying of ammonium nitrate may be accomplished, for example, by spraying the hot and concentrated aqueous solution of ammonium nitrate on cooling to form small crystals upon spraying.

Another way is to spray the ammonium nitrate melt. A third way is steam crystallization. In it, ammonia vapor is introduced into the same space as 35 nitric acid vapor, whereby ammonium nitrate crystallizes. Thus, the ammonium nitrate is only prepared during processing.

The particle size of ammonium nitrate can also be affected in various ways by recrystallization. The controllable parameters here include, for example, the concentration of the solution, the temperatures at the various stages of recrystallization, the cooling rate of the solution, and / or the use of filtration.

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Further, the ammonium nitrate, which is more stabilized against weathering in the absence of additives, is characterized in that its physical properties, such as particle size and / or specific surface area, are adapted as an oxidizing agent to remain essentially unchanged when thermally cyclized. In addition, its detonation properties are adapted as an oxidizing agent to remain essentially unchanged during thermal cyclisation of ammonium nitrate. Ammonium nitrate is also characterized in that it is substantially non-physically degradable, i.e., remains thermally stable during heat treatment at about 107 ° C for about 400 hours.

In addition to the oxidizing agent, the invention also relates to a composition for producing a gas, particularly for a gas generator of a vehicle safety device. The composition comprises a flammable substance and an oxidizing agent containing ammonium nitrate. At least part or all of the oxidizing agent is the oxidizing agent of the invention, i.e. ammonium nitrate, which is in powder form, i.e. ungranulated and additionally free of additives to stabilize the ammonium nitrate in the gas producing composition against temperature changes due to temperature changes.

The combustible material may include, for example, carbon, such as activated carbon. The combustible material may also include one or more organic compounds such as hydrocarbons. One or more organic compounds of the combustible material do not substantially dissolve ammonium nitrate. Due to the insolubility of ammonium nitrate in the combustible material, the porosity of the ammonium nitrate and thus its specific surface area remain essentially unchanged. As an example of a hydrocarbon, fuel oil can be mentioned. Here, the ammonium nitrate may be part of the pasty substance which it forms together with the combustible material, but still without changing its physical structure as a result of temperature changes.

In addition to the oxidizing agent and the flammable substance, the composition may also include additives that affect the rate of combustion. In addition to ammonium nitrate, the oxidizing agent may include one or more oxidizing agents. However, they are characterized in that they do not form mixed crystals and / or other solid solutions with ammonium nitrate such that the physical form typical of ammonium nitrate is altered. The composition is a multicomponent multi-component mixture. The composition is packaged in such a way that its moisture content does not change at any point in its life cycle.

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In explosions, ammonium nitrate produces nitrogen, oxygen and water (2 NH4NO3 2 N2 + O2 + 4 H2O). In explosives, it also reacts with carbon to produce carbon dioxide. The end products of the explosion are all clean and safe gases. When using ammonium nitrate, all the necessary oxygen is obtained from ammonium nitrate by using it in the correct stoichiometric ratio in the final explosive mixture. This also avoids the formation of solids by the non-combustible ingredient and hence the need for filtration thereof, and does not generate harmful gases, but still produces sufficient gas to fill the safety device at high speed. Physically

20185160 prh 02 -01-20199 more stable ammonium nitrate also facilitates the choice of composition ratios, reducing the potential for toxic gases such as carbon monoxide and nitrogen nitrates.

The explosives may be either single-component or multi-component. Combustion of multicomponent doped gas formation compositions, in which the ammonium nitrate of the invention can be used as an oxidizing agent, can be better controlled, whereby the combustion gases can be harmless and prevent particulate formation, and metal vapors are not properly selected. However, they have had the problem of structural strength, in which the explosive tablets deteriorate due to, for example, temperature variations. By using ammonium nitrate, which is more stabilized against temperature fluctuations, i.e. physical changes, it is possible to prepare gas-forming and explosive mixtures which are more resistant to weathering when exposed to temperature fluctuations. With the ammonium nitrate in the form of a fine powder or similar bulking agent, the compositions containing it as a ha 2 deceptive are not susceptible to weathering tablets or similar granular unit forms.

The compositions comprising ammonium nitrate are readily flammable, delayed, and have a controlled fire rate under the pressure of the explosion event and do not contain any dangerously explosive components. Ammonium nitrate-containing explosives are not toxic and do not produce toxic decomposition products when the other components of the explosive are correctly selected. Degradation is not present in the products of the invention, or at least it is less, since their particle size can no longer be reduced to such an extent that it has an effect of increasing the detonation rate. The particle size of the explosive or its components affects the detonation rate such that smaller particles have a higher detonation rate.

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The particle size of the material and its specific surface area are typically relative to one another.

Yet another object of the invention is a gas generator or a gas delivery system for a vehicle security device such as a car, and a vehicle security system using the gas generating composition of the invention. In a gas generator and similar systems, the composition of the invention is used to produce gas. More specifically, the gas 10 generator employs a composition for producing a gas comprising the oxidizing agent of the invention, ammonium nitrate, which is in powder form and without additives to stabilize the ammonium nitrate in the gas producing composition against the rash of ammonium nitrate caused by temperature changes. The fuel used in the gas generator is, for example, carbon or organic matter or both.

The invention also relates to a process for processing ammonium nitrate into an oxidizing agent into a gas producing composition 20, in particular for a gas generator for a vehicle safety device.

In the process, ammonium nitrate is processed by one or more methods for stabilizing ammonium nitrate, without additives, against weathering caused by temperature changes when used as an oxidizing agent in a gas generator in a gas producing composition. In addition, in the process, ammonium nitrate is powdered, i.e. un Granulated, for use in a gas generating composition of a gas generator. With the process, the invention also relates to an oxidizing agent for the gas generator 30 of a vehicle safety device for a gas producing composition and / or gas generator obtainable by the process of the invention.

Still further objects of the invention are the use of an oxidizing agent of the invention in a gas generating composition of a vehicle safety device and / or in a gas generating composition.

20185160 prh 02 -01-20199 as well as the use of the composition in the gas generator of a vehicle safety device.

Figure 2 illustrates an exemplary inflator or gas formation system 10 that is part of the airbag system 200 assembly. Airbag system 200 includes at least one airbag 202 and connected to the inflater 10 includes a gas generating composition according to the invention, air bag 202 so that it is fluid communication with the airbag located inside si10. The airbag system 200 may also include (or be associated with) a collision sensor 210. The collision sensor 210 includes a known collision sensor algorithm that controls the operation of the airbag system 200, for example, in the form of activating the inflation device 15 in the event of a collision.

The airbag system 200 may also be a wider and more comprehensive vehicle passenger restraint system 180 including additional elements, such as a seat belt assembly 150. Figure 20 2 is a schematic diagram of one exemplary restraint system embodiment. The seat belt assembly 150 includes a seat belt housing 152 and a seat belt 100 extending from the housing 152. The seat belt retractor mechanism 154 (e.g., a spring-loaded mechanism) may be coupled to the end portion of the seat belt 25. Additionally, the belt pretensioner 156 comprising the gas-forming / auto-ignition composition may be coupled to the belt pretensioner mechanism 154 for operating the pretensioner mechanism in the event of a collision.

The seat belt assembly 150 may also include (or may be associated with) a collision sensor 158 (e.g., an inertia sensor or an acceleration sensor) including a known collision sensor algorithm that controls the use of a belt pretensioner 156, such as a pyrotechnic actuator. The vehicle restraint may be equally valid

20185160 prh 02 -01-20199 such as an airbag deployed for the driver or passenger of the vehicle, such as an airbag deployed for the car, side impact protection or pedestrian or the like.

In addition to the airbag inflators, the ammonium nitrate cartridges of the invention may be used in all gas-filled devices, such as vehicle seat belt pretensioners and safety nets. In addition to airbags, tur10 curtains and seat belt pretensioners, the invention is also applicable to other applications requiring rapid gas formation and / or gas filling, which require very inexpensive solutions that have low environmental impact and low health impacts during the manufacturing process and other life of the device.

With the oxidizing agent of the invention and the composition containing it, the explosive produces a large amount of combustion gases relative to the weight of the explosive. This makes lighter inflation possible. The combustion temperature will also remain low enough to improve passenger safety.

It is to be understood that the foregoing description and the accompanying drawings are intended only to illustrate the present invention. Thus, the invention is not limited to the embodiments set forth above or as defined in the claims, but many variations and modifications of the invention which are within the scope of the inventive concept defined in the appended claims will be apparent to those skilled in the art.

Claims (14)

1. An oxidizing agent in a gas producing composition of a vehicle security device comprising an ammonium nitrate, Which, as said oxidizing agent, is in powder form, characterized in that - ammonium nitrate, said oxidizing agent being ammonium nitrate without additives to stabilize the ammonium nitrate in the gas-producing composition 10 against weathering caused by temperature changes, - the detonation properties of the ammonium nitrate are adapted to remain essentially unchanged during the thermal cycling of the ammonium nitrate as said powdered oxidant. An oxidizing agent according to claim 1, characterized in that the ammonium nitrate has a particle size of 0.5 to 1000 µm as an oxidizing agent. 20 An oxidizing agent according to claim 1 or 2, characterized in that said ammonium nitrate without additives for stabilizing the ammonium nitrate in the gas-producing composition against weathering due to temperature changes is obtained by one or more of the following processes: thermal cycling, grinding, atomization, recrystallization and / or vaporization. An oxidizing agent according to any one of claims 1 to 3, characterized in that the ammonium nitrate has a particle size and / or The 30 female surface area, as the oxidizing agent, is adapted to remain essentially unchanged during thermal cyclisation of ammonium nitrate. 20185160 prh 10 -09- 2018 An oxidizing agent according to any one of claims 1 to 4, characterized in that the ammonium nitrate is substantially non-decomposable in its physical structure at a temperature of about 107 ° C for about 400 hours. A composition for producing a gas for a gas generator of a vehicle security device comprising a combustible material and an oxidizing agent comprising ammonium nitrate, characterized in that at least some or all of the oxidizing agent is An oxidizing agent according to any one of claims 1-5. Composition according to Claim 6, characterized in that the combustible material comprises carbon. 15 Composition according to Claim 6 or 7, characterized in that the combustible material comprises one or more organic compounds which are essentially insoluble in ammonium nitrate. 20 Composition according to one of Claims 6 to 8, characterized in that the oxidizing agent comprises, in addition to ammonium nitrate, one or more oxidizing agents which do not form mixed crystals and / or other solid solutions with ammonium nitrate. A gas generator, in particular for a vehicle security device, which uses a composition as defined in claims 6-9 for producing gas or a composition comprising an oxidizing agent as defined in claims 1-5. A process for processing ammonium nitrate into a gas generating composition for a gas generator of a vehicle safety device, wherein ammonium nitrate is powdered as an oxidizing agent for use in a gas generating gas producing composition, characterized in that the ammonium nitrate is oxidized in a production composition, the processing of which, as a result of its processing, the detonation properties of ammonium nitrate as said powdered oxidant remain essentially unchanged upon thermal pulping of ammonium nitrate. An oxidizing agent for a gas generator of a vehicle safety device for a gas producing composition and / or gas generator obtainable by the process of claim 11. 15 Use of an oxidizing agent according to any one of claims 1 to 5 in a vehicle generator gas generator in a gas generating composition and / or gas generator. Use of a composition 20 according to any one of claims 6 to 9 in a gas generator for a vehicle security device.