KR100420563B1 - Gas-generating agent composition - Google Patents

Abstract

A gas generator composition comprising a fuel, an oxidizing agent, and an additive, the fuel comprising at least one high energy nitrogen-containing organic compound and at least one low energy nitrogen-containing organic compound, wherein the low energy nitrogen-containing organic compound A gas generator composition having a 50% average particle diameter of 40 μm or less.

Description

Gas generator composition {GAS-GENERATING AGENT COMPOSITION}

BACKGROUND ART An airbag device, which is one of rider protection devices, has been widely adopted in recent years to improve the safety of vehicle occupants. The principle is that the sensor detects a collision and acts to transmit an electrical signal, activate the gas generator, deploy the airbag, and mitigate the impact of the occupant on the collision. Examples of the performance required for a gas generator include generating a gas containing no harmful substances, generating a sufficient gas in a desired time.

In recent years, instead of the metal azide compounds used so far as gas generating agents, gas generating agents in which nitrogen-containing organic compounds are used as fuels and in combination with inorganic oxidizing agents have been proposed. These have the advantage that the amount of gas generated is large and the risk is low in the manufacturing process. However, most of the gas generators fueled by these nitrogen-containing organic compounds have a high heat of combustion of 2500 J / g or more, and since the generated gas is high temperature and high pressure, many coolants are required in the gas generator. Moreover, since slag by-produced at the time of combustion is high temperature, fluidity | liquidity is high, and a slag may flow out of a gas generator, and in a worst case, it may burn a rider. Although improvement is recognized by using a lot of coolant in any case, the size of a gas generator is increased and it goes against the flow of the miniaturization and weight reduction of a gas generator.

Then, the method of forming the slag which shows a high viscosity even in high temperature range by adding a slag forming agent, and collecting it efficiently is proposed. Particularly, Japanese Unexamined Patent Application Publication No. 4-265292 discloses a method of increasing the collection efficiency by adding both a low temperature slag former represented by silicon dioxide and a high temperature slag former which generates a solid having a melting point near or above the combustion temperature. have. However, the slag forming agent itself does not contribute substantially to gas generation, and the gas generation amount of the gas generating agent decreases with the increase in the addition amount of the slag forming agent. In addition, the combustion rate of the gas generating agent is difficult to adjust because of the increase in the addition amount of such a slag forming agent.

On the other hand, the gas generators disposed in the gas generators are molded into a certain shape in order to stabilize the combustion of the gas generators and to control the gas generation behavior during combustion. The burning rate of the gas generating agent changes depending on the constituents of the gas generating composition and the particle size of the gas generating agent molded body. Therefore, in the case of a gas generator with a slow burning rate, rapid gas generation is enabled in a short time by reducing the unit shape of the gas generator molded body or increasing the total surface area thereof. Conversely, in the case of a gas generating agent with a high combustion rate, the desired gas generation behavior is made possible by increasing the unit shape of the gas generating agent molded body or reducing its total surface area.

In most cases, the combustion characteristics in the gas generator are determined by the combustion behavior of the gas generator used. The combustion characteristics of gas generators are generally evaluated with a curve of pressure versus time in a tank obtained, for example, by operating the gas generator in a 60 liter tank. In recent years, so-called depower technology has attracted attention so as not to harm the crew during airbag deployment. For this purpose, for example, in a 60-liter tank test of a gas generator, it is desired to smooth the gas generation rate of 10 to 20 milliseconds from ignition and increase the gas generation rate after 20 milliseconds. Such a gas generator suppresses the gas generation rate at the beginning of combustion and exhibits more ideal occupant protection performance..Combustion behavior of the gas generating agent changes the shape of the gas generating body molded product and calculates the gas generating amount. The combustion behavior can be controlled to some extent. The relationship between the shape of the gas generating agent and the amount of gas generation has been known for a long time in the field of propellant, and for example, by referring to the Gunpowder Handbook p279 (Kyoritsu Publishing Co., Ltd. 1987), the preferred shape of the gas generating agent molded body is easily Can be determined.

It is also possible to combine two or more kinds of gas generator compositions having different combustion rates in a layered manner and to control the combustion behavior in multiple stages. In this way, Japanese Patent Laid-Open No. 6-48880 is used to control the combustion characteristics of the gas generator. In addition, Japanese Patent Laid-Open No. 6-107108 and Japanese Patent Laid-Open No. 6-107109 disclose a gas generating agent having a coating of a combustion inhibitor which is inert on a part of the gas generating surface. All of them form a gas generator molded body by combining the gas generator compositions of different combustion rates in layers. Such a gas generating agent does not ignite, it burns in the layer which is comparatively hard to burn, and suppresses the initial gas generation rate in a 60 liter tank test. These gas generating agents required more processes than before when molding in order to combine gas generating compositions of different combustion rates into layers. Moreover, since at least 2 or more types of gas generating agent compositions are needed, the cost for manufacture was also enormous.

In addition, Japanese Patent Application Laid-open No. Hei 10-87390 and Japanese Patent Laid-Open No. Hei 10-324588 disclose a gas generator molded body in which a gas generator shape is defined. These are intended to achieve the desired combustion performance by defining the shape of the gas generator so that as the gas generator is burned, the combustion surface area of the gas generator is not as small as possible but rather large. However, since any shape has a single hole or a porous tube shape and has a cavity in the gas generator molded body, the filling density when the gas generator is filled is low. In addition, since the shape of the gas generating agent is limited, it is difficult to change the shape of the gas generating agent in correspondence with gas generators of various shapes.

The present invention is a gas generator composition useful for gas generators for occupant protection devices such as automobile airbags and pretensioners, which does not require a complicated manufacturing process in molding a molded article of a gas generator, The present invention provides a gas generator composition that is not limited and exhibits combustion characteristics that realize more ideal occupant protection performance.

The present invention is an automobile airbag or pretensioner that can be used to protect the occupant in the crash of the car, etc. The present invention relates to a gas generator composition useful for gas generators for occupant protection devices. In particular, the present invention relates to a gas generator composition for realizing combustion characteristics preferable as a gas generator.

1 is a schematic diagram of an airbag gas generator 1 used in each embodiment of the present invention.

2 is a graph showing the results of a 60 liter tank test.

3 is a table showing the results of a 60 liter tank test.

(The best mode for carrying out the invention)

The gas generator composition of the present invention contains a fuel, an oxidant, and an additive. The fuel comprises at least one nitrogen-containing organic compound having a high combustion rate and at least one nitrogen-containing organic compound having a low combustion rate.

That is, in the gas generator composition of the present invention, the fuel is composed of at least one high energy nitrogen-containing organic compound and at least one low energy nitrogen-containing organic compound. Moreover, the 50% average particle diameter of the low energy nitrogen-containing organic compound is 40 µm or less, more preferably 20 µm or less.

The gas generator using the gas generator which consists of the gas generator composition of this invention is a combustion curve obtained by the 60-liter tank test WHEREIN: The combustion speed from ignition to about 20 ms is slow, and the combustion speed after 20 ms becomes fast. Moreover, the gas generator composition of this invention shows the pressure index of about the same grade as the conventional gas generator composition. Therefore, the ideal combustion characteristics can be realized by using the gas generator composition of the present invention in a gas generator.

It demonstrates in more detail.

In the present invention, the high-energy nitrogen-containing organic compound used The enthalpy produced is high, it burns relatively easily, and shows a fast burning rate. The high-energy nitrogen-containing organic compound may have a enthalpy of 200 kJ / mol (standard state) or more, preferably 100 kJ / mol or more, specifically, amino tetrazole, nitroguanidine, triamino guanidine nitrate, and the like. At least 1 sort (s) chosen from group is mentioned.

In the present invention, the low-energy nitrogen-containing organic compound used is The product has a low enthalpy, is hard to ignite, and shows a slow burning rate. As the low-energy nitrogen-containing organic compound, a product having an enthalpy of 200 kJ / mol (standard state) or less can be used, preferably 300 kJ / mol or less, and specific examples thereof include guanidine nitrate and oxamide.

In the present invention, the combination of the high-energy nitrogen-containing organic compound and the low-energy nitrogen-containing organic compound is not limited, but the difference in the enthalpy produced is preferably 200 kJ / mol or more.

Here, as a high-energy nitrogen-containing organic compound, amino tetrazole has a high nitrogen content, and the handling safety is comparatively high. desirable. In addition, nitroguanidine is also very suitable as a high-energy nitrogen-containing organic compound because of the large number of generated gas moles.

In addition, low-energy nitrogen-containing organic compounds usually have a low combustion rate when combined with an oxidant alone, and are rarely used for gas generators. Guanidine nitrate is preferred because of its relatively easy availability and low price.

The production enthalpy difference when using amino tetrazole as a high-energy nitrogen-containing organic compound and guanidine nitrate as a low-energy nitrogen-containing organic compound is 598 kJ / mol, and nitroguanidine as a high-energy nitrogen-containing organic compound is low-energy. The difference in production enthal ratio when using guanidine nitrate as the nitrogen organic compound is 296 kJ / mol.

The mixing ratio of the high energy nitrogen-containing organic compound and the low energy nitrogen-containing organic compound is 10: 1 to 1:10, preferably 5: 1 to 1: 5 by weight. The content of the gas generator composition as a fuel is 15 to 5 wt%.

Furthermore, the mixing ratio in the case where amino tetrazole is used as the high energy nitrogen-containing organic compound and guanidine nitrate as the low energy nitrogen-containing organic compound is preferably in the range of 3 to 1 to 1 as 3 by weight. The mixing ratio in the case of using nitroguanidine as the high energy nitrogen-containing organic compound and guanidine nitrate as the low-energy nitrogen-containing organic compound is preferably in the range of 5 to 1 to 1 to 1 by weight. If the amount of guanidine nitrate is too large, a significant reduction in the combustion rate occurs, and if it is too small, desirable combustion performance cannot be obtained.

The 50% average particle diameter of the low energy nitrogen-containing organic compound is 40 µm or less, more preferably 20 µm or less. In practice, as the 50% average particle diameter becomes smaller, the combustion rate from the ignition of the gas generating composition to about 20 ms is slowed down. Low-energy nitrogen-containing organic compounds, especially guanidine nitrate, are difficult to grind and have been pulverized up to 40 µm or less, but there have been no examples of using them as a gas generator. However, when the 50% average particle diameter is 40 µm or more, the effect of low-energy fuel is ineffective. It is not recognized, and the fall of the combustion speed in the initial stage of combustion is not enough.

Moreover, in press molding of the gas generating composition, the crush strength cannot be sufficiently obtained. Moreover, when 50% average particle diameter is 5 micrometers or less, since it requires enormous cost for grinding | pulverization, it is not preferable, but the effect of this invention can be acquired. Further, in press molding of the gas generator composition of the present invention, since the guanidine nitrate pulverized to 40 µm or less exhibits a function as a fixing agent, it is possible to obtain a tablet of a gas generator composition having a high crush strength (high hardness).

The oxidizing agent that can be used in the present invention can oxidize a fuel composed of the above-mentioned high-energy nitrogen-containing organic compounds and low-energy-containing nitrogen organic compounds, such as oxylates such as nitrates, halides and chromates, oxides and peroxides. If there is, we can adopt. Very preferably at least one selected from the group consisting of nitrates, perchlorates, chlorates of alkali metals or alkaline earth metals and basic copper nitrates is preferred. Moreover, at least 1 sort (s) chosen from the group which consists of a mixture of phase-stabilized ammonium nitrate or ammonium perchlorate and an nitrate, perchlorate, chlorate, or basic copper nitrate of an alkali metal or alkaline earth metal is also preferable. More preferred is strontium nitrate composed of a highly viscous slag-forming metal component by combustion.

The oxidizing agent should just determine the content in the vicinity of the equivalent of the gas generator composition is completely combusted and stoichiometrically, but in the gas generator composition which has largely missed the equivalent, it will bring about a significant increase in CO or NOx gas in the combustion gas. What is necessary is just to determine within the range of 30-70 weight% with respect to the whole gas generating composition. If the amount is less than 30% by weight, the oxygen supply amount may be insufficient, resulting in incomplete combustion, and harmful CO gas may be generated. On the other hand, when it exceeds 70 weight%, there exists a possibility that the content of fuel may be reversed, and the gas required at the time of airbag deployment may not be supplied.

Strontium nitrate, which is preferable as the oxidant in the present invention, may be used alone, or may be used as a mixed oxidant by adding an alkali metal nitrate, ammonium perchlorate, or basic copper nitrate. Specific examples include strontium nitrate and potassium nitrate, strontium nitrate and ammonium perchlorate, or a combination of strontium nitrate and basic copper nitrate.

The mixed oxidizing agent in the gas generator composition of the present invention can increase the combustion rate and give a good combustion gas when a small amount of alkali metal nitrate and basic copper nitrate are added. Moreover, when a small amount of ammonium perchlorate is added, since the number of gas generating gas of a gas generating agent increases, it is especially useful as a gas generating composition used for a pretensioner.

Especially when potassium nitrate is added, the effect is exhibited by content which is 10 weight% or less with respect to the whole gas generating composition. When more than 10% by weight of potassium nitrate is used, the outflow slag generated by combustion of the gas generator composition increases. These potassium-derived slag is difficult to filter in the filter in the gas generator, and may cause bag damage or burn to the crew. Moreover, when potassium nitrate is used a lot, it becomes difficult to suppress the initial combustion rate which is a characteristic of the gas generating composition of this invention, and there exists a possibility that crew addability may increase.

It is preferable that content in the case of adding basic copper nitrate is 30 weight% or less with respect to the whole gas generating composition. When using basic copper nitrate, it differs from the case where potassium nitrate is used, and slag can be filtered easily. Therefore, although it can tolerate up to 30 weight%, when it exceeds this, the burning rate of a gas generating composition will fall and there exists a possibility that a desired burning rate may not be obtained.

The additives include slag forming agents and binders. In the gas generating composition of the present invention, it is preferable to use silicon nitride or silicon carbide as the slag forming agent. Silicon nitride and silicon carbide are called fine ceramics and are thermally stable and are used as high-strength heat-resistant materials, but have a property of decomposing in a high temperature oxidizing atmosphere. By using this property, it functions as both slag formation and gas generation. The content of silicon nitride or silicon carbide is preferably in the range of 0.5 to 10% by weight, and at 0.5% by weight or less, a sufficient effect cannot be expected in the above-described slag collection, and when the content of the fuel or oxidant exceeds 10% by weight, There is a risk of generating a gas shortage because it is relatively reduced.

In particular, by adding fine particles of silicon nitride or silicon carbide during the pulverization of the fuel or oxidant, the effect as an anti-caking agent is also recognized. In addition, silicon nitride or silicon carbide is characterized by being capable of exhibiting slag formation ability without lowering the combustion rate of the gas generating composition of the present invention containing a fuel of low energy. In the case where the required amount of SiO ₂ is added as the slag forming agent, a significant reduction in the combustion rate is caused, which is not preferable in the present invention.

In addition, it is preferable to use hydrotalcites represented by the following general formula as a binder and slag forming agent.

{M ²⁺ _1-ｘ M ³⁺ _ｘ (OH) ₂ } ^{ｘ +} {A ^n- _{ｘ / n} ㆍ mH ₂ O} ^ｘ

here,

M ²⁺ : divalent metals such as Mg ²⁺ , Mn ²⁺ , Fe ²⁺ , Co ²⁺ , Ni ²⁺ , Cu ²⁺ , Zn ²⁺ ,

^Trivalent metals such as M ³⁺ : Al ³⁺ , Fe ³⁺ , Cr ³⁺ , Co ³⁺ , In,

^{A n-: OH -, F -} , Cl -, No 3 -, CO 3 2-, So 4 2-,

N-valent anions such as Fe (CN) ₆ ^3- , CH ₃ COO ⁻ , oxalate ions, salicylic acid ions,

X: 0 <Ｘ≤0.33.

Specifically, the above hydrotalcite-flow formula _{Mg 6 Al 2 (OH) 16} CO 3 · synthetic hydrotalcite or the formula represented by the _{4H 2 O Mg 6 Fe 2 (} OH) 16 CO 3 · represented by 4H ₂ O Pyrroleite can be illustrated. This hydrotalcite is a porous substance having crystal water and is extremely effective as a binder of a nitrogen-containing organic compound-based gas generator. In particular, with respect to the gas generator composition containing tetrazole as a main component, it is possible to obtain a hardness much higher than the tablet hardness of a typical azide gas generator.

It is considered that this hydrotalcite is common and has a property of easily adsorbing moisture, and this property acts to firmly bind each component of the gas generating agent. In addition, the tablet using this binder does not change the characteristics and combustibility of the gas generating agent even when the thermal shock is repeated due to high temperature and low temperature, and thus, the deterioration of aging when the vehicle is actually mounted on a vehicle is reduced. Moreover, it is thought that hydrotalcites react in the case of combustion of a gas generating agent, for example, in the case of synthetic hydrotalcite, as shown in following Reaction Formula 1.

_{Mg 6 Al 2 (OH) 16} CO 3 · 4H 2 O

→ 6MgO + Al ₂ O ₃ + CO ₂ + 12H ₂ O

For this reason, since no harmful gas is generated and the reaction itself is an endothermic reaction, there is also an effect of reducing the calorific value of the gas generating agent. Moreover, the decomposition product itself of synthetic hydrotalcite also forms the spinel which can be easily filtered by the slag reaction which is an acid base reaction shown in following formula (2).

MgO + Al ₂ O ₃ → MgAl ₂ O ₄

The content of the binder is preferably in the range of 2 to 10% by weight. When the content of the binder is less than 2% by weight, it is difficult to achieve the function as a binder. When the content of the binder is more than 10% by weight, the content of the fuel or the oxidant is relatively decreased. Cause shortage There is concern. In addition, by adding hydrotalcites to the gas generator composition, the sensitivity of the gas generator composition is lowered, and as a result, the effect of improving the safety during manufacture is also recognized.

Moreover, a cellulose binder or a natural polymer can be used as a binder. This binder is well suited for extrusion molding gas generator compositions. As a specific example of the said cellulose binder, at least 1 sort (s) chosen from the group which consists of carboxymethyl cellulose, methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, and hydroxypropyl methyl cellulose is mentioned. As a specific example of the binder of a natural polymer, at least 1 sort (s) chosen from the group which consists of guar rubber or tragacanth rubber is mentioned. As for content of these cellulose binders or a natural polymer, 2-10 weight% is preferable.

At least 1 sort (s) chosen from the group which consists of polyacrylic acid, polyacrylic acid soda, polyacrylamide, and these 2 or 3 types of copolymers other than a cellulose binder is mentioned. As for these addition amount, 0.5-10 weight% is preferable, and the improvement of the heat resistance of a gas generating agent composition is recognized as the effect.

Moreover, in the case of extrusion molding, the moldability is improved by adding a silane compound. Specific examples of the silane compound that can be used include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ -Glycidoxy propyl trimethoxy silane, γ- glycidoxy propyl methyl diethoxy silane, γ- glycidoxy propyl triethoxy silane, γ- methacridoxy propyl methyl dimethoxy silane, γ- methacryloxy propyl tree Methoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropylmethyldimethoxysilane, N-β- (amino Ethyl)-[gamma] -aminopropyltrimethoxysilane, N- [beta]-(aminoethyl)-[gamma] -aminopropyltriethoxysilane, [gamma] -aminopropyltrimethoxysilane, [gamma] -aminopropyltriethoxysilane, N- Phenyl- (gamma)-aminopropyl trimethoxysilane, tetramethoxysilane, methyl Methoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, tetraethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, hexyl Trimethoxysilane, hexyltriethoxysilane, decyltrimethoxysilane, hexamethyldisilazane and the like. As for the addition amount of these silane compounds, 0.5-10 weight% is preferable.

Next, the preferable combination of each component in the gas generating composition of this invention is demonstrated. In the gas generator composition of the present invention, a combination of 5-amino tetrazole and guanidine nitrate as fuel, strontium nitrate as oxidant, silicon nitride as slag forming agent, and synthetic hydrotalcite as binder are preferable. Regarding these contents, 10 to 30% by weight of 5-amino tetrazole, 5 to 30% by weight of guanidine nitrate, 30 to 70% by weight of strontium nitrate, 0.5 to 10% by weight of silicon nitride, and 2 to 10% by weight of synthetic hydrotalcite are preferable. In order to further increase the combustion rate, it is preferable to contain 10 wt% or less of potassium nitrate or 30 wt% or less of basic copper nitrate. Although guanidine nitrate is low energy, there exists a tendency for a burning rate to fall with content. In addition, since guanidine nitrate is hard to grind, it is difficult to grind, and a pin mill or ball mill used as a general grinding means in the production of gas generating agents can easily obtain a 50% average particle diameter of 50 µm or more, but 40 µm. It is extremely difficult to grind to 20 micrometers or less especially hereafter, and it is necessary to use special grinders, such as a jet mill. In addition, the slag forming agent is preferably silicon nitride. By adding silicon nitride, good slag collecting property is realized without lowering the combustion speed. As a binder, synthetic hydrotalcite is preferable, and not only the hardness improvement of a gas generating agent composition but also the fall of a calorific value and favorable slag collection ability are recognized.

In the gas generator composition of the present invention, a combination using nitroguanidine and guanidine nitrate as fuel, strontium nitrate as oxidant, silicon nitride as slag forming agent, and cellulose binder as binder are also preferable. Regarding these contents, 20 to 55% by weight of nitroguanidine, 5 to 30% by weight of guanidine nitrate, 30 to 60% by weight of strontium nitrate, 0.5 to 10% by weight of silicon nitride, 2 to 10% by weight of cellulose binder or synthetic hydrotalcite It is preferable to contain 10 wt% or less of potassium nitrate or 30 wt% or less of basic copper nitrate in order to further increase the burning rate. In the gas generator composition of the present invention including nitroguanidine and guanidine nitrate as fuel, a form in which the gas generator is molded by extrusion molding is particularly preferable, and in this case, the binder is particularly advantageous to a cellulose binder. The kind of binder will not be specifically limited if water is a solvent and shows moderate viscosity. However, in the case where the oxidant contains phase stabilized ammonium nitrate, the use of an anionic binder causes ionic reactions and heat resistance, which is not preferable. In this case, it is preferably a nonionic binder. As the slag forming agent, silicon nitride is preferable. By adding silicon nitride, good slag collection property is realized without reducing the combustion speed.

In addition, in the gas generator composition of the present invention, 5-amino tetrazole and guanidine nitrate as fuel, strontium nitrate and ammonium perchlorate as oxidizing agent, polyacrylamide as a binder, and a silane compound for the purpose of improving moldability during extrusion. Combinations using are preferred. Regarding these contents, 10 to 30% by weight of 5-amino tetrazole, 5 to 30% by weight of guanidine nitrate, 10 to 50% by weight of strontium nitrate, 10 to 50% by weight of ammonium perchlorate, 0.5 to 10% by weight of polyacrylamide, Preference is given to 0.5 to 10% by weight of the silane compound. It is preferable to add water as a solvent at the time of extrusion molding, and it is good at this time that the silane compound used has the characteristic to melt | dissolve in water.

The gas generator composition of the present invention may be in the form of powder, granules or pellets, or may be press-molded or extruded. As a shape which can be shape | molded, a tablet form, a single hole cylinder shape, a porous cylinder shape, etc. are mentioned, for example.

Next, the manufacturing method of the gas generating composition of this invention is demonstrated. The gas generating composition of the present invention can be implemented by any method of press molding or extrusion molding. In addition, by heat treatment after molding, the gas generant composition is sufficiently dried, and prevention of ignition delay due to moisture and improvement of environmental resistance can be achieved.

In the case of press molding, first, an anti-caking agent is added to the fuel component and the oxidant, and mixed with a V-type mixer, followed by grinding. A predetermined amount of the pulverized fuel component oxidant and the pulverized molding aid are weighed out, mixed uniformly with a V-type mixer, put into a press molding machine, and then heat treated. The obtained gas generator molded body is used as a gas generator composition.

In the case of extrusion molding, the fuel components and the oxidizing agent are pulverized in the same manner, each component is weighed by a spiral mixer, 8-25% by weight of water is added to the outer shell, and thoroughly kneaded to obtain a viscous wet liquid. Thereafter, using a vacuum kneading extrusion machine, extrusion molding into a desired shape is cut and then subjected to heat treatment. The extruded molded product thus obtained is used as the gas generating composition.

The present invention will be described in more detail by way of examples.

MEANS TO SOLVE THE PROBLEM As a result of earnestly examining so that the said subject might be solved, it discovered that the combustion behavior of a gas generating agent is made favorable by defining the composition of a gas generating agent, and came to complete this invention.

That is, the gas generator composition of the present invention contains a fuel, an oxidizing agent, and an additive, and the fuel is composed of at least one high energy nitrogen-containing organic compound and at least one low energy nitrogen-containing organic compound, 50% average particle diameter of the low-energy nitrogen-containing organic compound is characterized in that less than 40㎛.

The rate of combustion of the fuel is largely dependent on the properties of the oxidant used and its rate of combustion. Therefore, in the present invention, in connection with the discussion of the combustion rate, the nitrogen-containing compound having a high combustion rate is described as a high-energy-containing nitrogen organic compound, and the nitrogen-containing compound having a low combustion rate is a low-energy-containing nitrogen organic compound, focusing on the combustion rate of the fuel. It was defined as a compound.

When two or more kinds of fuels are usually used as the fuel of the gas generator composition, the combustion speed thereof does not exceed the range of the combustion speed of the gas generator composition composed of the respective fuel bodies, and is constant at approximately the intermediate combustion speed. It shows an approximate value. However, the combustion rate of the gas generator made of the gas generator composition which has made an extreme difference in the energy of the fuel is not constant, and in the gas generator, the combustion of the high energy fuel for a certain period from ignition is low energy. In the form of fuel inhibition, the initial combustion rate is slowed down. Then, the internal pressure in the gas generator is sufficiently high, and the combustion rate of the gas generator is increased.

As in the present invention, the 50% average particle diameter of the low-energy nitrogen-containing organic compound is 40 µm or less, more preferably 20 µm or less, and the combustion inhibitory effect of the high-energy fuel by the low-energy fuel can be suitably obtained. .

Here, the 50% average particle size based on the number is a method of expressing the particle size distribution on the basis of the number. The particle size at the time is called the 50% average particle size of the number basis.

In the 60 liter tank test, the gas generating agent which consists only of the gas generating composition of this invention as described above shows the combustion behavior which is slow in the initial stage of combustion, and becomes faster after that. Therefore, the combustion rate of the gas generating agent which consists only of the said gas generating agent composition of this invention changes without being substantially constant. Conventionally, since the combustion rate of the gas generator which consists only of one type of gas generator composition was substantially constant, the gas generator which consists only of the gas generator composition of this invention differs fundamentally from the conventional gas generator.

Therefore, in order to obtain a gas generator suitable for a gas generator for a passenger safety device such as an air bag, two or more kinds of gas generator compositions having different combustion rates are combined in a layer to form a gas generator molded body or the shape of a gas generator molded body. If it is specified, desired combustion behavior can be obtained without any particular action.

Moreover, the gas-generating agent composition which can be approximated that the conventional gas-generating agent composition shows a substantially constant combustion rate in the range of the pressure which a gas generator actually operates is selected. If the gas generator composition has a large ratio depending on the pressure of the combustion speed, the combustion speed is remarkably changed by the pressure change in the gas generator due to the change of the ambient temperature or the powdering of the gas generator and the protection of the crew such as the airbag. It is because it is not preferable as a gas generating composition of the gas generator for apparatus.

The pressure dependence of combustion rate It can be obtained by the pressure index of the following general formula for the combustion rate of the explosives. The combustion behavior by the shape of the gas generator is obtained by first approximating the following gas generation rate, and the combustion performance of the gas generator can be estimated roughly.

V = aP ^ｎ (Vieille expression)

V: burning speed, a: exponent depending on composition or temperature

P: pressure, n: pressure index.

In the above general formula, a relatively low pressure index and a small change in combustion rate due to pressure are preferable as a gas generator composition of a gas generator for a crew protection device such as an air bag because the pressure dependency of the combustion rate is small.

The gas generator composition of the present invention exhibits a pressure index of approximately the same level as a conventional gas generator composition.

(Example 1)

5-amino tetrazole as fuel: 24.7 parts by weight (50% particle diameter, 15 mu m), and guanidine nitrate: 11.9 parts by weight (50% particle diameter, 30 mu m), strontium nitrate as the oxidizing agent: 53.4 parts by weight (50% particle diameter, 13 Micron), silicon nitride: 5.0: parts by weight (50% particle diameter, 5 µm) as a slag forming agent, and synthetic hydrotalcite: 5.0 parts by weight (50% particle diameter, 10 µm) as a binder were dry mixed by a V-type mixer.

Next, 15 parts by weight of water was mixed while spraying with respect to the total amount of the mixed powder, followed by wet granulation to obtain granules having a particle diameter of 1 mm or less. After heat-drying this granule, it press-molded with the rotary tableting machine, and the tablet of the gas generating composition of this invention of diameter 5mm and height 1.5mm was obtained.

This tablet was filled with 40 g of the gas generator 1 shown in FIG. In addition, the gas generator 1 includes a combustion chamber 8 in which a central ignition chamber 7 in which an ignition device 2 and a telephone medicine 3 are arranged, and a gas generator 4 in the vicinity thereof are filled, and also It consists of the cooling filter chamber 9 by which the wire mesh 5 of the periphery was arrange | positioned, and combustion gas passes through the cooling filter chamber 9, and is made to blow out to the exterior from the gas ejection opening 6 of a housing | casing. After the gas generator 1 was installed in a container having a volume of 60 liters, the gas generator 1 was operated, the gas was discharged into the container, and the time change of the pressure in the container was measured. The result of this 60 liter tank test is shown in Table 1 of FIG.

(Example 2)

5-amino tetrazole as fuel: 19.7 parts by weight (50% particle diameter, 15 mu m), and guanidine nitrate: 19.7 parts by weight (50% particle diameter, 10 mu m), strontium nitrate as an oxidant: 50.6 parts by weight (50% particle diameter) , 13 µm), 5.0 parts by weight of silicon nitride (50% particle diameter, 5 µm) as a slag forming agent and 5.10 parts by weight of synthetic hydrotalcite (50% particle diameter, 10 µm) as a binder were dry mixed by a V-type mixer. . Next, the mixture was sprayed with 15% by weight of water based on the total amount of the mixed powder, and then wet granulated to obtain granules having a particle diameter of 1 mm or less. After heat-drying this granule, it press-molded with the rotary tableting machine, and the tablet of the gas generating composition of this invention of diameter 5mm and height 1.5mm was obtained.

This tablet was filled with 40 g of the gas generator 1 shown in FIG. 1, and the same test as in Example 1 was carried out. The obtained result is shown by the graph of FIG. 2 and Table 1 of FIG. In the graph of FIG. 2, the line a shows the result of this embodiment.

(Example 3)

5-amino tetrazole as fuel: 19.4 parts by weight (50% particle diameter, 15 mu m), and guanidine nitrate: 19.4 parts by weight (50% particle diameter, 10 mu m), strontium nitrate as an oxidizing agent: 44.2 parts by weight (50% particle diameter, 13 Μm), and potassium nitrate: 7.0 parts by weight (50% particle diameter, 35 μm) silicon nitride as a slag forming agent: 5.0 parts by weight (50% particle diameter, 5 μm) and synthetic hydrotalcite as a binder: 5.0 parts by weight (50% particle diameter) , 10 µm) was dry mixed with a V-type mixer. Next, 15% by weight of water was mixed with the total amount of the mixed powders while spraying, followed by wet granulation to obtain granules having a particle diameter of 1 mm or less. The granules were heated and dried, and then press-molded with a rotary tablet press to obtain tablets of the gas generator composition of the present invention having a diameter of 6 mm and a height of 1.5 mm.

This tablet was filled with 40 g of the gas generator 1 shown in FIG. 1, and the same test as in Example 1 was carried out. The obtained result is shown in Table 1 of FIG.

(Example 4)

Nitroguanidine as fuel: 41.5 parts by weight (50% particle diameter, 20 mu m), and guanidine nitrate: 8.2 parts by weight (50% particle diameter, 10 mu m), strontium nitrate as the oxidant: 35.3 parts by weight (50% particle diameter, 13 mu m), And potassium nitrate: 5.0% by weight (50% particle diameter, 35 mu m), silicon nitride as a slag forming agent: 5.0 parts by weight (50% particle diameter, 5 mu m) and synthetic hydrotalcite as a binder: 5.0 parts by weight (50% particle diameter, 10 [Mu] m) was dry mixed with a V-type mixer. Next, the mixture was sprayed with 15% by weight of water based on the total amount of the mixed powder, and then wet granulated to obtain granules having a particle diameter of 1 mm or less. The granules were heated and dried, and then press-molded with a rotary tablet press to obtain tablets of the gas generator composition of the present invention having a diameter of 5 mm and a height of 2.0 mm. This molded object was filled with 35 g of the gas generator 1 shown in FIG. 1, and the same test as in Example 1 was carried out. The obtained result is shown in Table 1 of FIG.

(Example 5)

Nitroguanidine as fuel: 42.1 parts by weight (50% particle diameter, 20 mu m), and guanidine nitrate: 8.7 parts by weight (50% particle diameter, 30 mu m), strontium nitrate as an oxidizing agent: 39.2 parts by weight (50% particle diameter, 13 mu m), 5.0 parts by weight of silicon nitride (50% particle diameter, 5 mu m) as a slag forming agent and 5.0 parts by weight of methyl cellulose as a binder were dry mixed with a V-type mixer. Next, 15% by weight of water was mixed with the sprayed whole powder, followed by kneading while vacuum degassing with a kneader. The obtained clay gas generator composition was molded by a screw extrusion machine, and then heated and dried to obtain a cylindrical gas generator composition molded body having an outer diameter of 3 mm and a height of 2 mm.

This molded object was filled with 35 g of the gas generator 1 shown in FIG. 1, and the same test as in Example 1 was carried out. The obtained result is shown in the graph of FIG. 2, and Table 1 of FIG. In the graph of FIG. 2, the b line shows the result of this Example.

(Example 6)

Nitroguanidine as fuel: 34.7 parts by weight (50% particle diameter, 20 mu m), and guanidine 9.5 parts by weight (50% particle diameter 10 mu m), strontium nitrate as an oxidizing agent: 36.8 parts by weight (50% particle diameter, 13 mu m), and Basic copper nitrate: 10.5 parts by weight (50% particle diameter, 11 mu m), silicon nitride: 3.5 parts by weight (50% particle diameter, 5 mu m) as a slag forming agent and 5.0 parts by weight of methyl cellulose as a binder were dry mixed by a V-type mixer. . Next, the mixture was sprayed while spraying 15% by weight of water based on the total amount of the mixed powder, and then kneaded while vacuum degassing by a kneader. Clay-like gas generator composition obtained by screw extrusion This was heat-dried after shaping | molding, and the molded object of the columnar gas generator composition with an external shape of diameter 4mm and height 2mm was obtained.

This molded object was filled with 35 g of the gas generator 1 shown in FIG. 1, and the same test as in Example 1 was carried out. The obtained result is shown in Table 1 of FIG.

(Comparative Example 1)

5-aminotetrazole as fuel: 30.9 parts by weight (50% particle diameter, 15 mu m), strontium nitrate as an oxidizing agent: 57.9 parts by weight (50% particle diameter, 13 mu m), silicon nitride as a slag forming agent: 5.0 parts by weight (50% particle diameter) , 5 µm) and synthetic hydrotalcite as a binder: 5.0 parts by weight (50% particle diameter, 10 µm) were dry mixed with a V-type mixer. Next, 15 parts by weight of water was mixed while spraying with respect to the total amount of the mixed powder, and then wet granulated to form granules having a particle diameter of 1 mm or less. The granules were heated and dried, and then press-molded with a rotary tablet press to obtain a gas generator tablet having a diameter of 5 mm and a height of 2.0 mm.

This tablet was filled with 40 g of the gas generator 1 shown in FIG. 1, and the same test as in Example 1 was carried out. The obtained result is shown in the graph of FIG. 2, and Table 1 of FIG. In the graph of FIG. 2, the line c has shown the result of this comparative example.

(Comparative Example 2)

Guanidine nitrate as fuel: 50.6 parts by weight (50% particle diameter, 15 mu m), strontium nitrate as an oxidizing agent: 39.4 parts by weight (50% particle diameter, 13 mu m), silicon nitride as slag forming agent: 5.0 parts by weight (50% particle diameter, 5 µm) and synthetic hydrotalcite as a binder: 5.0 parts by weight (50% particle diameter, 10 µm) were dry mixed by a V-type mixer. Next, 15 parts by weight of water was mixed with the whole of the mixed powder while spraying, and then wet granulated to obtain granules having a diameter of 1 mm or less. The granules were heated and dried, and then press-molded with a rotary tablet press to obtain gas generator tablets having a diameter of 5 mm and a height of 1.5 mm.

40 g of this tablet was filled in the gas generator 1 shown in FIG. 1, and the test similar to Example 1 was done. The obtained result is shown by the graph of FIG. 2 and Table 1 of FIG. In the graph of FIG. 2, the line d has shown the result of this comparative example.

(Comparative Example 3)

5-amino tetrazole as fuel: 24.7 parts by weight (50% particle diameter, 15 mu m), and 11.9 parts by weight of guanidine nitrate (50% particle diameter 50 mu m); strontium nitrate as the oxidant: 53.4 parts by weight (50% particle diameter, 13 mu m) , 5.0 parts by weight of silicon nitride (50% particle diameter, 5 mu m) as a slag forming agent and 5.0 parts by weight of synthetic hydrotalcite (50% particle diameter, 10 mu m) as a binder were dry mixed by a V-type mixer. Next, 15 parts by weight of water was mixed while spraying with respect to the total amount of the mixed powder, followed by wet granulation to obtain granules having a particle diameter of 1 mm or less. After heat-drying this granule, it press-molded with the rotary tableting machine, and the gas generator tablet of diameter 5mm and height 1.5mm was obtained.

This tablet was filled with 40 g of the gas generator 1 shown in FIG. 1, and the same test as in Example 1 was carried out. The obtained result is shown in the graph of FIG. 2, and Table 1 of FIG. In the graph of FIG. 2, the line e has shown the result of this comparative example.

In Examples 1-6, the molded object of the gas generating composition of this invention is suppressed from the ignition to 10-20 ms in 60-liter tank test, as is clear from the result of FIG. 2 and FIG. It can be seen that the gas generation rate after 20 ms has risen more steeply, and after 40 ms, the pressure is equivalent to that of the conventional one, so that the combustion performance of the preferred gas generator can be obtained.

Here, according to the comparative example 1, guanidine nitrate is not added. In other words, when the fuel is composed of one high-energy nitrogen-containing organic compound, the 60-litre tank pressure from 20 to 20 ms is reduced. The larger, the expander becomes more accessible. Moreover, according to the comparative example 2, in the case of the gas generator composition which consists only of guanidine nitrate which is a low energy fuel, the fall of the extreme combustion rate is recognized rather than FIG. 2, and it becomes unsuitable as a gas generator. Moreover, according to the comparative example 3, when the 50% average particle diameter of guanidine nitrate exceeds 40 micrometers, it will be 60 liter tank pressure which does not show a big difference with the comparative example 1, and the effect like this invention is not recognized.

As is clear from the above description, the gas generator composition of the present invention comprises at least two or more nitrogen-containing organic compounds in which the fuel is composed of a high-energy nitrogen-containing organic compound having a fast burning rate and a low-energy-containing nitrogen organic compound having a slow burning rate. The present invention provides a gas generator composition having a 50% average particle diameter of the low-energy nitrogen-containing organic compound of 40 µm or less, which exhibits a preferable combustion behavior as a gas generator. Therefore, when the gas generator which consists of the gas generator composition of this invention is used, the gas generator which has the combustion performance with little passenger-incompatibility can be implemented simply and at low cost.

The present invention is a gas generator composition useful for a gas generator of a gas generator for a passenger protection device such as an automobile air bag or a pretensioner, which does not require a complicated manufacturing process and is not limited to the shape of the gas generator. It is very preferable as a gas generating agent composition which shows the combustion characteristic which realizes more ideal rider protection performance.

Claims (27)

A gas generator composition containing a fuel, an oxidizing agent, and an additive, the fuel comprising at least one high energy nitrogen-containing organic compound and at least one low energy nitrogen-containing organic compound, and further comprising the low energy nitrogen The gas generator composition, characterized in that the 50% average particle diameter of the organic compound is 40㎛ or less. The gas generator composition of claim 1, wherein a 50% average particle diameter of the low energy nitrogen-containing organic compound is 20 µm or less. The gas generant composition according to claim 1, wherein the high energy nitrogen-containing organic compound is at least one member selected from the group consisting of amino tetrazole nitroguanidine and triamino guanidine nitrate. The gas generator composition according to claim 1, wherein the low-energy nitrogen-containing organic compound is guanidine nitrate. The method of claim 1, wherein the high-energy nitrogen-containing organic compound is at least one selected from the group consisting of amino tetrazole, nitroguanidine, triamino guanidine nitrate, and the low-energy nitrogen-containing organic compound is guanidine nitrate. Gas generating composition, characterized in that. The gas generator composition according to claim 1, wherein the oxidizing agent is at least one selected from the group consisting of nitrates, perchlorates, chlorates or basic copper nitrates of alkali metals or alkaline earth metals. The method of claim 1, wherein the oxidizing agent is at least one member selected from the group consisting of a mixture of a phase stabilized ammonium nitrate or ammonium perchlorate and an nitrate, perchlorate, chlorate or basic copper nitrate of an alkali or alkaline earth metal. Gas generator composition. The gas generator composition according to claim 1, wherein the additive is silicon nitride or silicon carbide. The gas generator composition according to claim 1, wherein the additive is a hydrotalcite represented by the following general formula. {M ²⁺ _1-ｘ M ³⁺ _ｘ (OH) ₂ } ^{ｘ +} {A ^n- _{ｘ / n} ㆍ mH ₂ O} ^ｘ (here, M ²⁺ : divalent metals such as Mg ²⁺ , Mn ²⁺ , Fe ²⁺ , Co ²⁺ , Ni ²⁺ , Cu ²⁺ , Zn ²⁺ , ^Trivalent metals such as M ³⁺ : Al ³⁺ , Fe ³⁺ , Cr ³⁺ , Co ³⁺ , In, ^{A n-: OH -, F -} , Cl -, No 3 -, CO 3 2-, SO 4 2-, N-valent anions such as Fe (CN) ₆ ^3- , CH ₃ COO ⁻ , oxalate ions, salicylate ions, X: 0 <X ≦ 0.33). 10. The hydrotalcite of claim 9, wherein the hydrotalcites are synthetic hydrotalcites represented by the formula Mg ₆ Al ₂ (OH) ₁₆ CO ₃ 4H ₂ O or Mg ₆ Fe ₂ (OH) ₁₆ CO ₃ 4H ₂ O. Gas generator composition characterized in that the pyrrolite represented by. The method of claim 1, wherein the additive is at least one cellulose-based binder or a natural polymer selected from the group consisting of carboxymethyl cellulose, methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose. Gas generating agent composition. The gas generator composition according to claim 1, wherein the additive is at least one selected from the group consisting of polyacrylic acid, polyacrylic acid soda, polyacrylamide, and two or three copolymers thereof. The gas generant composition of claim 1, wherein the additive is a silane compound. The gas generant composition according to claim 1, wherein the fuel is 5-amino tetrazole and guanidine nitrate, the oxidant is strontium nitrate, and the additive is silicon nitride and synthetic hydrotalcite. The gas generant composition according to claim 1, wherein the fuel is 5-amino tetrazole and guanidine nitrate, the oxidizing agent is strontium nitrate and potassium nitrate, and the additive is silicon nitride and synthetic hydrotalcite. The gas generant composition according to claim 1, wherein the fuel is 5-amino tetrazole and guanidine nitrate, the oxidant is strontium nitrate and basic copper nitrate, and the additive is silicon nitride and synthetic hydrotalcite. The gas generant composition according to claim 1, wherein the fuel is nitroguanidine and guanidine nitrate, the oxidizing agent is strontium nitrate, and the additive is silicon nitride. The gas generant composition according to claim 1, wherein the fuel is nitroguanidine and guanidine nitrate, the oxidizing agent is strontium nitrate and potassium nitrate, and the additive is silicon nitride. The gas generant composition according to claim 1, wherein the fuel is nitroguanidine and guanidine nitrate, and the oxidizing agent is strontium nitrate and basic copper nitrate. The gas generator composition of claim 1, wherein the fuel is 5-amino tetrazole and guanidine nitrate, the oxidizing agent is strontium nitrate and ammonium perchlorate, and the additive is a polyacrylamide and a silane compound. 10 to 30% by weight of 5-amino tetrazole as high energy nitrogen-containing organic compound, 5 to 30% by weight of guanidine nitrate as low-energy nitrogen-containing organic compound, 30 to 70% by weight of strontium nitrate as oxidizing agent, A gas generator composition containing 0.5 to 10 wt% of silicon nitride and 2 to 10 wt% of synthetic hydrotalcite as an additive. 2. Nitroguanidine 20-55% by weight as the high-energy nitrogen-containing organic compound, 5-30% by weight of guanidine nitrate as the low-energy nitrogen-containing organic compound, 30-60% by weight of strontium nitrate as the oxidizing agent, silicon nitride as an additive A gas generator composition containing 0.5 to 10% by weight and 2 to 10% by weight of synthetic hydrotalcite. 2. Nitroguanidine 20-55% by weight as the high-energy nitrogen-containing organic compound, 5-30% by weight of guanidine nitrate as the low-energy nitrogen-containing organic compound, 30-60% by weight of strontium nitrate as the oxidizing agent, silicon nitride as an additive A gas generating composition comprising 0.5 to 10% by weight and 2 to 10% by weight of a cellulose binder. 10 to 30% by weight of 5-amino tetrazole as high-energy nitrogen-containing organic compound, 5 to 30% by weight of guanidine nitrate as low-energy nitrogen-containing organic compound, 10 to 50% by weight of strontium nitrate as oxidizing agent, 10 to 50% by weight of ammonium perchlorate, 0.5 to 10% by weight of polyacrylamide and 0.5 to 10% by weight of silane compound as additives. 25. The gas generant composition according to any one of claims 21 to 24, further containing 10 wt% or less of potassium nitrate. 25. The gas generant composition according to any one of claims 21 to 24, further containing 30% by weight or less of basic copper nitrate. 24. The gas generator composition according to claim 23, wherein the cellulose binder is at least one selected from the group consisting of carboxymethyl cellulose, methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose and hydroxypropylmethyl cellulose. .