JP2013504507A - Pyrotechnic gas generation - Google Patents

Abstract

The present invention relates to a pyrotechnic gas generator comprising a composition comprising guanidine nitrate, basic copper nitrate and potassium perchlorate. Characteristically, potassium perchlorate accounts for 8-20% of the total weight of the pyrotechnic gas product, and the composition is at least selected from metal oxides, metalloid oxides and mixtures thereof Further comprising one oxide, the at least one oxide having a melting point lower than the combustion temperature of the pyrotechnic gas product and 1% to 5% of the total weight of the pyrotechnic gas product Accounted for. The at least one oxide improves the low pressure combustion of pyrotechnic gas products.
[Selection] Figure 1

Description

  The present invention relates to pyrotechnic gas-generating products suitable for use in automobile occupant protection systems such as airbag inflation or seat belt pretensioners.

  Over the past 20 years, the technical field of car occupant protection has made tremendous progress. The latest generation vehicles in the future will integrate several safety systems of the airbag type or seat belt pretensioner type that operate by the explosion of pyrotechnic gas products in the passenger compartment. Among several airbag-type systems, frontal crash airbags (driver or occupant airbags) and side impact airbags (curtains or chest protection airbags) are prominent.

Due to the demands of automakers to reduce the cost of gas generators for airbags, such pyrotechnic charges must satisfy the following requirements simultaneously.
・ Gas generated by the explosion of explosives is not toxic, that is, the content of carbon monoxide, nitrogen oxides and chlorine compounds is low.
-The amount of gas generated by the composition (total amount of gas generated by explosion) must be large so that a high expansion force can be obtained. This is given by the product of the molar gas generation (mol / kg) of the composition and the combustion temperature (K).
• In this connection, the amount of solid particles generated by the explosion, which can constitute hot spots that can damage the airbag walls, must be small.
The explosion temperature is not too high (ideally less than 2200K) and the gas temperature in the airbag is low enough not to impair the physical integrity of the occupant. Since the explosion temperature is low, the thickness of the airbag can be reduced, and the adjustment plate and filter in the airbag can be reduced, thereby simplifying the design of the gas generator. Eventually, the gas generator will be low in cost and weight and volume.
It is necessary that the composition has a high expansion rate per unit area. The expansion rate is as follows: ρ is the density of pyrotechnic material (g / cm ³ ), n is the amount of mol gas generated (mol / g), Tc is the explosion temperature (Kelvin temperature), and Vc is the combustion rate (mm / s) , Ρ × n × Tc × Vc. That is, the expansion coefficient per unit area is represented by [mol · K · mm ⁻² · s ⁻¹ ].

  The side airbag system is different from the front airbag system in terms of time and arrangement required for deployment of the airbag. This time is usually shorter for side airbags (sides are 10-20 ms versus fronts 40-50 ms). In order to obtain a sufficient expansion rate per unit area (product ρ × n × Tc × Vc) due to the functional requirement that the airbag expands in a short time with respect to the side airbag, the pyrotechnic composition is a gas generator. It is required to have a high combustion rate (usually greater than 35 mm / s at 20 MPa and greater than 40 mm / s at 50 MPa) in the entire operating pressure range (usually about 20 to 80 MPa) in the combustion chamber of the vessel. In addition, the pyrotechnic composition must also have excellent ignitability characteristics to ensure that the airbag system is started. Finally, considering that the side shape of the explosive (pellet type) explosive used is usually tapered, the pyrotechnic composition ideally has a low pressure (where the low pressure is equal to or less than atmospheric pressure). Should be stable and have a sufficiently high burning rate.

  In addition, the side airbag system is completely pyrotechnic (gas is generated only by the explosion of explosives) and hybrid type (explosive explosive, pressurized and sealed in an airtight chamber) Two gas generator technologies may be required, what is referred to as both the amount of stored inert gas being derived from gas. In a hybrid gas generator, the explosive temperature of the explosive must not be too low so that the gas produced by the explosion is hot enough to compensate for the temperature drop caused by the volume expansion of the precompressed inert gas. . Ideally, the explosion temperature is required to be higher than 2000K.

  Accordingly, a person skilled in the art is a pyrotechnic composition having both an appropriate explosion temperature of about 2000 to 2200 K and a high combustion rate in the entire operating pressure range including low pressure, and a completely pyrotechnic gas for a side airbag. We are investigating compositions suitable for use in generators or hybrid gas generators.

Various types of pyrotechnic compositions have already been proposed. Recently, a pyrotechnic composition made from a mixture of basic copper nitrate (BCN) as oxidant and guanidine nitrate (GN) as reducing agent, optimally adjusted in terms of combustion temperature and combustion gas toxicity Things seem to have been proposed. By using both BCN / GN, the combustion temperature can usually be reduced to about 1800K. U.S. Pat. No. 5,608,183 describes such a plurality of compositions produced in a wet production process. However, these compositions have some major drawbacks:
・ There are many solid residues that cannot be captured by the filter. These residues are in the form of liquid copper droplets at the combustion chamber temperature of the gas generator and solidify when leaving the gas generator, and are generated by the decomposition of BCN. As a result, the hot solid particles damage the airbag walls.
・ Because it is difficult to ignite, it is necessary to use a large amount of igniter, which increases the cost of the gas generator.
・ Gas generation is not so high.
・ Combustion temperature is very low, making it difficult to share with hybrid gas generators.
-The combustion speed is low (about 20 mm / s at 20 MPa), and it is difficult to use for a complete pyrotechnic gas generator or a hybrid gas generator for side airbags.

  In order to overcome the first of the major drawbacks mentioned above, a refractory oxide such as aluminum oxide (alumina) or silicon oxide is included in the pyrotechnic composition for the purpose of agglomerating the liquid combustion residue of BCN. The technique of making it be proposed is proposed. That is, U.S. Pat. No. 6,143,102 describes a composition based on BCN and GN, which is also produced in a wet production process and contains up to 5% by weight of silicon oxide as refractory oxide. This agglomeration effect is caused by the fact that 1950K, the melting point (or softening point) of silicon oxide, is higher than or very close to the combustion temperature Tc = 1800K of the composition, and therefore the softened solid oxide is liquid copper. Those skilled in the art know to agglomerate droplets. At the end of combustion, the backbone of the pyrotechnic block is obtained. However, it was immediately apparent that the incorporation of such aggregated oxides was disadvantageous for the combustion rate even in small amounts. This is because the agglomeration effect generates particulate gangue that remains in contact with the (pellet) pyrotechnic block during combustion and restricts the heat flow to the unburned surface. Therefore, this type of pyrotechnic composition has the disadvantages of low combustion rate and low gas generation. In order to compensate for the low burning rate of the composition, in US Pat. No. 6,143,102 a second metal oxide type (aluminum, titanium, zirconium, zinc or magnesium oxide) is used as a ballistic catalyst. It has been proposed to add a refractory additive. Finally, the addition of silicon oxide and metal oxides totaling around 10% by weight is very detrimental to the gas evolution of the composition.

  In order to improve the ignitability of BCN and GN based compositions, techniques for adding potassium perchlorate to the compositions have been proposed. That is, European Patent Application No. 1526121 describes that a small amount (less than 5% by weight) of perchlorate (specifically potassium perchlorate) is added to improve the ignitability of the composition. Has been. By adding such a small amount of perchlorate, the combustion rate and gas generation amount of the composition can be slightly increased. However, even if this improvement is made, the gas generator of the side airbag is used. Is insufficient.

  U.S. Patent Application 2006/0016529 includes guanidine nitrate (40-60 wt%), basic copper nitrate (35-50 wt%), alkali metal perchlorate (European Patent Application No. 10% by weight) but also limited to small amounts), and compositions based on metal oxides (1-5% by weight) which function as ballistic catalysts and flocculants. This metal oxide is intended for agglomeration in the same manner as in accordance with the teaching of US Pat. No. 6,143,102 (see above).

  To add significant amounts of potassium perchlorate (a limited amount, usually less than 30%, which does not cause an unexpected increase in combustion temperature) to significantly increase the gas generation rate and to obtain the composition When a specific manufacturing method is used, the burning rate is also significantly increased. That is, French Patent Application No. 2892117 is based on guanidine nitrate (reducing agent), a small amount of basic copper nitrate (main oxidant), and a large amount of potassium perchlorate (co-oxidant) of 30 wt% or less. The composition is described. Because there is a small amount of basic copper nitrate, there is no need to add a flocculant to the composition (a small amount of copper particles produced by BCN are acceptable within the scope of the specification) to obtain the composition Because of the large amount of potassium perchlorate obtained using this specific production method, a high combustion rate can be achieved without adding a ballistic catalyst at medium and high pressures. These compositions are the prior art closest to the present invention.

Thus, French Patent Application No. 2892117 combines advantageous combinations of potassium perchlorate (about 14%) and basic copper nitrate with the use of a dry compression process in the following respects: It teaches that a removed pyrotechnic composition is obtained.
・ Combustion temperature of about 2100K ・ High combustion speed at high pressure ・ High gas generation ・ Good ignitability ・ Since the amount of solid (copper) particles generated during combustion is small, flocculant can be eliminated

  However, this type of composition has the limitation that the combustion pressure is higher than atmospheric pressure. If self-sustaining combustion is not possible under atmospheric pressure and a large pressure exponent of less than 2 MPa, extinguishment occurs at the end of combustion, depending on the operating pressure and explosive shape. Those skilled in the art will appreciate the effects caused by the addition of perchlorate, ie the combustion rate at high pressure, but not so much at low pressure, and when perchlorate is added I know the amount will be large. At low pressure, the high expansion generated by the large amount of gas generation with a small amount of solid particles causes a slight return of heat flow to the unburned zone. In this case, it is difficult to maintain self-combustion.

In the pyrotechnic composition, the situation where stable self-combustion at a low pressure is not possible is a major drawback when the composition is used in a gas generator for an air bag mainly for the following reasons.
・ Since the pressure index is large, there is a risk of extinguishing at low pressure at the beginning or end of operation, so a co-charge may be required to maintain combustion of the main explosive at low pressure . Therefore, the gas generator becomes bulky, and does not become small and high in cost.
・ To extinguish the fire at the end of operation (when the pressure in the combustion chamber of the gas generator drops below the lower self-combustion pressure of the pyrotechnic composition), that is, to generate combustion gas that inflates the airbag according to the intended functional requirements There is a risk of extinguishing the fire with unburned material that does not contribute. Furthermore, such unburned matter can be gradually deteriorated by thermal decomposition at a high temperature remaining in the combustion chamber. This slow degradation due to pyrolysis causes the release of gas bursts that are difficult to control, and occasionally the release of small sized solid particles that cannot be captured by the filter. Such a phenomenon generates fumes at the end of the operation that are disadvantageous to comply with the standards of toxicity and respirable particle emissions practiced in the art (USCAR).

In such a situation, the inventors wanted to propose an improved pyrotechnic gas generator that simultaneously satisfies the following requirements.
・ Moderate combustion temperature (about 2100K)
・ High gas generation (greater than 30 mol / kg)
-Small amount of solid particles generated during combustion-Good ignitability-High burning rate at high pressure (greater than 35 mm / s at 20 MPa, greater than 40 mm / s at 50 MPa)
-Combustion (and advantageously the combustion rate) is stable and self-combustes at low pressure, ideally at atmospheric pressure, avoiding the risk of extinguishing explosives during gas generator operation

In the present invention, the inventors select from a small amount (1% to 5% by weight) of metal oxide, metalloid oxide and mixtures thereof in a composition containing an appropriate amount of potassium perchlorate. At least one oxide that has a melting point below the combustion temperature of this pyrotechnic gas product (combustion disadvantageous to maintain a sufficiently high combustion rate at high pressure) The addition of (to avoid any flocculation effect of the residue) has shown great benefits with respect to the technical challenge of improving low pressure combustion while maintaining high combustion rates, especially at high pressure. The at least one oxide produces a homogeneous powder mixture (mainly comprising GN + BCN + KClO ₄ + the at least one oxide (see below)) used to produce the pyrotechnic of the present invention by a dry process. Are in the form of powder explosives with “particle size on the micron scale (usually 0.1-100 μm)” and / or “large specific surface area (> 20 m ² / g)”. These are the normal characteristics that make up this type.

  We therefore propose here a new high quality pyrotechnic used in a hybrid or fully pyrotechnic gas generator that is particularly suitable for use in a side airbag system.

The composition of the pyrotechnic gas generator according to the present invention (very suitable for an air bag) contains the following.
・ Guanidine nitrate (as a nitrogen-containing reducing agent)
・ Basic copper nitrate (as main oxidant)
・ Potassium perchlorate (as a secondary oxidant)

as a feature:
The potassium perchlorate accounts for 8% to 20%, preferably 10.5% to 20% by weight of the total weight of the pyrotechnic gas product.
The composition further comprises at least one oxide selected from metal oxides, metalloid oxides and mixtures thereof, wherein the at least one oxide is a total weight of the pyrotechnic gas generant. The melting point is lower than the combustion temperature of the pyrotechnic gas product.

The above four components (GN, BCN, KClO ₄ , and the above oxides) usually exceed 90% by weight of the pyrotechnic gas product of the present invention, more typically more than 95% by weight, Is over 98% by weight or 100% by weight. Obviously, optional additives such as manufacturing aids (eg calcium stearate) may be used.

  Guanidine nitrate is a fluid plastic that is suitable for imparting ballistic properties to pyrotechnics and for making pyrotechnics in a dry process because of their thermodynamic properties (especially gas generation). Selected as a reducing agent to give rheoplastic behavior. Such guanidine nitrate ensures the pyrotechnic safety, and compression molding in the dry process and optional, which ensures good densification of the pyrotechnic composition while limiting the applied compressive stress This is advantageous in that it has a fluid plastic behavior suitable for performing the pelletizing step. A method for producing a pyrotechnic gas product by a dry process usually includes four steps, which are described in International Publication No. WO2006 / 134311.

  Potassium perchlorate is present in the pyrotechnic gas product composition of the present invention in an appropriate amount (8 wt% to 20 wt% with reference to combustion temperature, ignitability, and target high pressure burning rate. % By weight). And it is advantageously greater than 10.5% by weight.

The function of the at least one (metal and / or metalloid) oxide is different from the prior art (see in particular US Pat. No. 6,143,102 and US Patent Application 2006/0016529) in order to obtain a high burning rate at high pressure. The burning temperature is higher than the melting point of the at least one (metal and / or metalloid) oxide without agglomerating the liquid copper particles that form the disadvantageous particulate matter host rock during the combustion during the combustion. The high composition (moderately containing KClO ₄ ) surprisingly ensures that it has the following properties:
・ Stable self-combustion at lower pressures than prior art compositions,
The combustion rate at low pressure is higher than the prior art composition,
And the function of potassium perchlorate in the composition is
A high burning rate at high pressure, close to the burning rate of the prior art composition,
The same or smaller pressure index as the prior art composition over the entire operating pressure range,
Can be understood to be essentially involved in

Thus, the pyrotechnic gas product of the present invention has good ignitability, does not generate many solid particles during combustion, and advantageously adjusts the following points.
・ Appropriate combustion temperature (about 2100K)
・ High gas generation ・ High combustion speed at high pressure, and
"Non-zero" burning rate at low pressure and atmospheric pressure

  The present invention proposes the first use of metal and / or metalloid oxides (known as ballistic catalysts and / or flocculants) for improved combustion at low pressure (see above).

  Therefore, the inclusion of 1 wt% or more of the at least one oxide in the pyrotechnic gas product of the present invention is involved in improving combustion at low pressure. Its content is limited to 5% by weight or less, especially in view of the amount of gas generated and combustion at high pressure.

  In order to obtain the pyrotechnic gas product of the present invention, the required properties (resulting from thermodynamic calculations, including combustion temperature, gas generation, solid residue content, oxygen balance and theoretical density) The required ratio of the above-mentioned components (components of pyrotechnic gas generation) that gives the above-mentioned conditions is a condition regarding the melting point of the at least one metal and / or metalloid oxide (the melting point is (Which has been confirmed by the present inventors in the combustion at low pressure) in advance, while ensuring that the combustion temperature of the pyrotechnic gas product containing at least one oxide as a constituent is satisfied. It is determined.

  The melting point of the at least one oxide (each of the only oxide or oxides present) present in the composition of the pyrotechnic gas product according to the invention is advantageously the pyrotechnic gas 50K or more lower than the combustion temperature of the product.

Preferably, the at least one oxide is selected from silicon oxide (SiO ₂ ), tungsten oxide (WO ₃ ) and molybdenum oxide (MoO ₃ ). Of these, silicon oxide (SiO ₂ ) is particularly preferable.

Advantageously, the pyrotechnic gas generant composition of the present invention comprises:
50% to 65% by weight of guanidine nitrate,
20% to 40% by weight of basic copper nitrate,
8% -20% by weight, preferably 10.5% -20% by weight potassium perchlorate, and
1% to 5% by weight, preferably 1% to 3% by weight of said at least one metal and / or metalloid oxide.

  Therefore, the pyrotechnic gas generation product of the present invention advantageously includes a first step of dry-mixing a plurality of powdery components and a second step of compressing the powdery mixture thus obtained. Obtained by the manufacturing process. After these two steps, an optional third step of granulating and, if necessary, a fourth step of shaping the granulate by pelletization to obtain a compressed pyrotechnic gas product thereafter. Is done.

  Therefore, the pyrotechnic gas product of the present invention is usually granular, pellet or block.

  Additives may be added after granulation to facilitate pelletization while minimizing the impact on the desired functional properties of the final product. This additive is advantageously of the stearate family and preferably consists of calcium stearate or magnesium stearate. The amount added is less than 1% by weight, preferably less than 0.5% by weight.

  The pyrotechnic gas product of the present invention is very suitable for incorporation into an air bag gas generator explosive. The pyrotechnic gas generator may be all or part of the explosive.

  In another aspect, the present invention relates to a gas generator including at least one pyrotechnic gas product. Such a gas generator is suitable for an airbag (see above).

FIG. 2 shows the combustion rate (propagation) curve at low pressure for the pyrotechnic gas product of the present invention and the prior art. FIG. 2 shows combustion rate curves over a wide pressure range for the pyrotechnic gas product of the present invention and the prior art.

  In the following, embodiments of the present invention, which are non-limiting, will be described. Compositions (of the pyrotechnic gas product of the present invention) according to some embodiments of the present invention are described below and compared with examples of prior art (pyrotechnic gas product) compositions.

  FIG. 1 shows the combustion rate (propagation) curves at low pressure for pyrotechnic gas products of the present invention and the prior art. Measurements were made on the granulate by standard burner technology (see below).

  FIG. 2 shows the burning rate curve over a wide pressure range for the pyrotechnic gas product of the present invention and the prior art. Measurements were made on the pellets in a pressure measuring bomb.

  Table 1 shows examples of the composition of the pyrotechnic gas product of the present invention and its characteristics. These compositions (pyrotechnic gas generants) are thermodynamically calculated for the granules or pellets produced from the above composition by a dry production process of powdered mixing-compression-granulation-arbitrary pelletization. Or evaluated by physical measurements.

As a function of the amount of oxide, the amounts of the main components (GN, BCN and KClO ₄ ) were adjusted so that the oxygen equilibrium value was maintained around −3%, so that the properties of the composition were directly from Table 1. Can be compared.

The main component used in the composition described in Table 1 is advantageously a median diameter (D50) of about 12 μm for guanidine nitrate, about 3 μm for BCN and about 10 μm for KClO _4. The fine particle size is characterized by

Oxides of metals or metalloids are used in the compositions of Examples 1-4, about 1950K _(SiO 2), characterized by a melting point of about 1070K (MoO ₃₎ and about 1750K (WO _3). Silicon oxide has a specific surface area of 100-200 m ² / g, molybdenum oxide has a median diameter of about 10 μm, and tungsten oxide has a median diameter of about 100 μm. .

  The compositions of Examples 1 to 4 constitute a pyrotechnic gas generator according to the invention, and the compositions of the reference examples (Comparative Examples A and B) are pyrotechnic gases according to prior art French patent application 2892117. Constitutes the product.

For each pyrotechnic gas product shown in Table 1, the combustion pressure lower limit was measured for the granulate by standard burner technology (ignition in a pressurized container). For this purpose, the granulate is introduced into a straw with a diameter of 7.4 mm arranged in a container with a capacity of 5 liters pressurized under an inert atmosphere (N ₂ ). Ignition is performed using hot wire, and then the combustion propagation velocity is measured using two soluble wires housed in straws at 100 mm intervals. Ignition was carried out at 20 ° C. for various container pressurization values until non-ignition of particulates of each composition was observed.

For each pyrotechnic gas product in Table 1, the burning rate (Vc) for the pellets was measured by ignition performed in a pressure measuring cylinder. To obtain a Vc (P) curve over a wide pressure range, ignition was performed for various explosive concentration values (35 kg / m ^{3 to} 175 kg / m ³ ).

The results in Table 1 indicate that the compositions of Examples 1 to 4 according to the present invention have the following matters.
Advantageously, properties are maintained with respect to density, combustion temperature and gas generation in comparison with the compositions of Comparative Examples A and B. These properties are important to play a major part in the expected function (swelling force) of the composition.
-Good suitability for densification, showing a low porosity measurement for the pellets. This densification suitability is important for the production of compressed granules and the production of pellets, whose geometry, diameter or thickness is easily adjusted according to the intended application. Also, the compressive stress applied during pelletization can be minimized, thereby reducing tool wear and pyrotechnic risks during the compression period.
・ Pellets having sufficient mechanical strength can be obtained. By containing an appropriate amount of SiO ₂ , MoO ₃ or WO ₃ type oxide, the mechanical strength of the pellet is not lowered to show a radial crushing strength value.

  The lower limit of the combustion pressure shown in Table 1 and the combustion rate curve at a low pressure shown in FIG. 1 show an appropriate amount of silicon oxide, molybdenum oxide or tungsten oxide type oxide (1.5 weight in the examples). % To 3% by weight), it is shown that the lower limit of the combustion pressure can be significantly lowered than in Comparative Examples A and B. Among the compositions of Examples 1-4, the most noticeable improvement was seen in the composition of Example 2 where the silicon oxide was 3% by weight. This is because Example 2 has a “non-zero” burning rate at atmospheric pressure, and generally has the highest burning rate over a pressure range of 0.1-1 MPa.

  Referring to FIG. 2, the ballistic characterization in the pressure measuring bomb obtained for the pellets of the plurality of compositions of Table 1 is that the compositions of Examples 1-4 range over a high pressure range of 20-50 MPa. It shows that a sufficiently high burning rate is maintained.

  The pyrotechnic gas product of Example 1 containing 1.5% by weight silicon oxide optimally solves a plurality of characteristics such as combustion temperature, gas generation amount, combustion pressure lower limit value, and combustion speed at high pressure. is there. In particular, this pyrotechnic gas product has the great advantage of maintaining a “non-zero” combustion rate at atmospheric pressure. When 3% by weight of silicon oxide is contained as in the composition of Example 2, there is more benefit in terms of combustion at ultra-low pressure, but conversely, the combustion rate at high pressure is reduced. These results indicate that the silicon oxide content is preferably less than 3% by weight in order to maintain sufficient ballistic characteristics in the high pressure range of 20 to 50 MPa.

  Of the various oxides tested, it was observed that the pyrotechnic gas generants of Examples 1 and 2 made according to the present invention with silicon oxide beneficially reduced the pressure index.

Composition based on BCN containing a high melting point refractory oxide such as aluminum oxide because the melting point of the contained oxide (SiO ₂ , MoO ₃ or WO ₃ ) is lower than the combustion temperature of the composition Like a thing, the combustion residue which aggregated in the form of the backbone of the pyrotechnic block which is the initial form of a pellet is not observed.

Claims (9)

A pyrotechnic gas generator comprising a composition comprising guanidine nitrate, basic copper nitrate and potassium perchlorate,
The potassium perchlorate accounts for 8% to 20% of the total weight of the pyrotechnic gas product;
The composition further comprises at least one oxide selected from metal oxides, metalloid oxides and mixtures thereof, wherein the at least one oxide is in the total weight of the pyrotechnic gas generant. A pyrotechnic gas product characterized by occupying 1% to 5% and having a melting point lower than the combustion temperature of the pyrotechnic gas product.   The pyrotechnic gas product according to claim 1, wherein the potassium perchlorate accounts for 10.5% to 20% of the total weight of the pyrotechnic gas product.   3. The pyrotechnic gas product according to claim 1, wherein a melting point of the at least one oxide is lower by 50 K or more than a combustion temperature of the pyrotechnic gas product. The at least one oxide is selected from silicon oxide (SiO ₂ ), tungsten oxide (WO ₃ ), and molybdenum oxide (MoO ₃ ). The pyrotechnic gas product according to claim 1. The pyrotechnic gas generation product according to claim 4, wherein the at least one oxide is made of silicon oxide (SiO ₂ ). 50% to 65% by weight of guanidine nitrate,
20% to 40% by weight of basic copper nitrate,
8% -20% by weight, preferably 10.5% -20% by weight potassium perchlorate, and
6. The composition according to claim 1, wherein the composition comprises 1% to 5% by weight, preferably 1% to 3% by weight of the at least one oxide. Pyrotechnic gas generator.   It is obtained by a drying process including a step of compressing a powder mixture containing each component as a powder, an optional granulation step, and, if necessary, a subsequent pelletization step The pyrotechnic gas generation product according to any one of claims 1 to 6, wherein   The pyrotechnic gas product according to any one of claims 1 to 7, wherein the shape is granular, pellet or block.   A gas generator suitable for an airbag, comprising at least one pyrotechnic gas product according to any one of claims 1 to 8.