JP3476771B2 - Manufacturing method of molded article of gas generating agent for airbag - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas generating agent molded body which is burned to inflate an airbag system to supply a gas component, and a method for manufacturing the same. More specifically, the present invention relates to a novel composition of a gas generant which becomes a working gas in an airbag system provided for protecting a human body mounted on an automobile, an aircraft or the like, and a dosage form thereof.

[0002]

2. Description of the Related Art When a vehicle such as an automobile collides at high speed,
In order to prevent passengers from injuring or dying due to inertia from crashing into hard parts inside the vehicle such as the steering wheel and windshield, gas is used to inflate the bag rapidly and prevent passengers from colliding with dangerous places. Bag systems are being developed. The requirements for the gas generant used in this airbag system are that the bag inflation time is very short, usually within 40 to 50 milliseconds, and that the atmosphere inside the bag is harmless to the human body, that is, the air composition inside the vehicle. It is very difficult to be close.

At present, examples of gas generating bases generally used in airbag systems include inorganic azide compounds, especially sodium azide. Sodium azide is excellent in terms of flammability, but the alkaline component produced as a by-product when gas is generated is toxic and does not satisfy the above requirements in terms of safety for passengers. Also,
Since it itself is toxic, there is concern about the environmental impact of its disposal.

In order to make up for these drawbacks, some so-called non-azide type gas generating agents have been developed which replace the sodium azide type. For example, JP-A-3-208878 discloses a composition containing tetrazole, triazole or a metal salt thereof and an oxygen-containing oxidizing agent such as an alkali metal nitrate as main components. In addition, Japanese Examined Patent Publication 64-6156,
Japanese Patent Publication No. 64-6157 discloses a gas generating agent containing a hydrogen-free metal salt of a bitetrazole compound as a main component.

Further, JP-B-6-57629 discloses a gas generating agent containing a transition metal complex of tetrazole or triazole. Further, in JP-A-5-254977, a gas generating agent containing triaminoguanidine nitrate is disclosed in JP-A-6-254.
239683 discloses a gas generating agent containing carbohydrazide, and JP-A-7-61885 discloses a gas generating agent containing cellulose acetate and a nitrogen-containing non-metallic compound containing nitroguanidine. Furthermore, in USP 5,125,684 15-30
The use of nitroguanidine as an energetic material co-existing with a% cellulosic binder is disclosed. Further, JP-A-4-265292 discloses a gas generating composition in which a tetrazole and triazole derivative is combined with an oxidizing agent and a slag forming agent.

[0006]

However, a nitrogen-containing organic compound generally produces only a chemical equivalent in combustion, that is, an amount of oxygen necessary for combustion of carbon, hydrogen and other elements in the compound molecule. When an oxidizer is used, it has a drawback that it has a larger calorific value than an azide compound.
As an airbag system, it is essential that not only the performance of the gas generant but also the size of the system itself that does not interfere with normal operation, but the calorific value of the gas generant during combustion is large. In addition, when designing the gas generator, additional parts for heat removal are required, and it is impossible to downsize the gas generator itself. Although it is possible to reduce the amount of heat generated by selecting the type of oxidant,
Corresponding to this, the linear burning rate also decreases, and the gas generation performance eventually decreases.

As described above, a gas generant composition comprising a nitrogen-containing organic compound generally has a chemical equivalent to that in combustion.
That is, when using an oxidizer that only generates the amount of oxygen required for combustion of carbon, hydrogen, and other elements to be oxidized in the nitrogen-containing organic compound molecule, compared to a gas generant composition using an inorganic azide compound. It has the disadvantages of high calorific value, high combustion temperature, and low linear burning rate.

As described above, the problem caused by the high combustion temperature is that the coolant contains a chemical reaction between the alkaline mist generated from the oxidizer component in the composition and the commonly used stainless steel coolant. The erosion causes the high temperature heat particles newly generated in the cooling section to be discharged to the outside of the inflator, thereby causing damage to the bag. However, if the alkaline mist generated from the oxidizer component and newly generated high-temperature hot particles can be stopped inside the combustion chamber by forming slag in the combustion chamber before reaching the cooling unit, even if it is a high-temperature gas Since the heat capacity of the gas is small, it is possible to establish an inflator system by using a small amount of coolant without seriously damaging the bag. As a result, a smaller-sized inflator can be realized.

Non-azide gas generant compositions using various nitrogen-containing organic compounds, including tetrazole derivatives, have been studied in the past. The linear burning rate of the composition varies depending on the kind of the oxidant to be combined, but generally, most of the compositions have a linear burning rate of 30 mm / sec or less.

The linear burn rate affects the shape of the gas generant composition to achieve the desired performance. In one shape of the gas generant composition, the burning time of the gas generant composition is determined by the smallest thickness distance of the thick portion and the linear burning rate of the gas generant composition. The bag deployment time required for an inflator system is approximately 40-60 ms.

In order to complete the combustion of the frequently used pellet-shaped and disk-shaped gas generant composition within this time, for example, when the linear burning speed is 20 mm / sec at a thickness of 2 mm, 1
It takes 00 msec to obtain the desired inflator performance. Therefore, the performance of the gas generant composition having a linear burning rate of about 20 mm / sec cannot be satisfied unless the thickness is about 1 mm. When the linear burning rate is around 10 mm / sec or less, it is an essential condition that the thickness of the thick portion is smaller.

Means for combining oxidants such as sodium nitrate and potassium perchlorate in order to improve the linear burning rate are known. However, sodium nitrate is sodium oxide and potassium perchlorate is potassium chloride in liquid or solid form. It is a very difficult technique to control the release amount to a level allowed by a normal filter when it is released in the form of fine powder outside the inflator and there is no slag forming agent.

A linear burning rate of about 10 mm / sec or less and a thickness of about 0.5 mm or less is essential to achieve the thickness of the thick portion in the pellet shape and the disk shape which are often used. However, it is practically impossible to produce a gas generant composition in the form of pellets and discs while enduring vibration of an automobile for a long period of time and being industrially stable.

[0014]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that a gas generant composition having a low linear burning rate is molded within a predetermined time. They have found that they can be combusted and their performance is sufficiently applicable as a gas generating agent for airbags, and have reached the present invention.

That is, according to the present invention, the gas generant composition is molded into a single-hole cylinder, and 70 kgf of the gas generant composition is molded.
Gas generating agent for airbags in which the relationship between the linear burning velocity r (mm / sec) and the thickness W (mm) under a pressure of / cm ² is 0.005 ≦ W / (2 · r) ≦ 0.1 Molded body, preferably
Linear burning rate of 1 to 12.5 under pressure of 70 kgf / cm ²
It is intended to provide a gas generant molding for an air bag, which is obtained by molding a gas generant composition in the range of mm / sec, more preferably 5 to 12.5 mm / sec into a single-hole cylindrical shape. Incidentally, when simply described as a linear burning rate in the present specification, it is 70 kgf / cm ²
Means under pressure.

The gas generant composition used in the present invention comprises a nitrogen-containing organic compound and an oxidizer, and a binder and, if necessary, a slag forming agent added. Preferably, the linear burning rate is 1 to 1 in order to suppress heat generation. A range of 12.5 mm / sec is used. INDUSTRIAL APPLICABILITY According to the present invention, it is possible to apply a gas generant composition having a linear burning rate of around 10 mm / sec or less, and it is possible to put into practical use an inflator system that is more compact including the quality of produced gas.

The nitrogen-containing organic compound that can be used in the present invention is a mixture of one or more selected from the group consisting of triazole derivatives, tetrazole derivatives, guanidine derivatives, azodicarbonamide derivatives and hydrazine derivatives. Specific examples of these include 5-oxo-1,
2,4-triazole, tetrazole, 5-aminotetrazole, 5,5′-bi-1H-tetrazole, guanidine, nitroguanidine, cyanoguanidine, triaminoguanidine nitrate, guanidine nitrate, guanidine carbonate,
Biuret, azodicarbonamide, carbohydrazide, carbohydrazide nitrate complex, oxalic acid dihydrazide,
A hydrazine nitrate complex etc. can be mentioned. Nitroguanidine and cyanoguanidine are preferable, and nitroguanidine is the most preferable compound because it has a small number of carbon atoms in the molecule. As nitroguanidine, there are low specific gravity nitroguanidine in the form of needles and high specific gravity nitroguanidine in the form of lumps, both of which can be used, but the high specific gravity nitroguanidine is safe and easy to handle in the presence of a small amount of water. The use of guanidine is more preferred.

The concentration of the compound varies depending on the number of carbon element, hydrogen element and other elements to be oxidized in the molecular formula, but it is usually used in the range of 25 to 60% by weight, preferably 30
Used in the range of up to 40% by weight. The absolute value varies depending on the type of oxidizer used, but if it is more than the theoretical oxidation amount, the trace CO concentration in the evolved gas increases, and if it is less than the theoretical oxidation amount, the trace NO _x concentration in the evolved gas increases. To do. The range in which the optimum balance between the two is maintained is most preferable.

Although various kinds of oxidizing agents can be used, an oxidizing agent selected from at least one nitrate containing a cation selected from alkali metals or alkaline earth metals is used. Although the amount varies depending on the kind and amount of the gas generating compound used, the amount is used in the range of 40 to 65% by weight, and particularly in relation to the above CO and NO _x concentrations.
A range of 45-60% by weight is preferred.

In addition, oxidants such as nitrite and perchlorate, which are widely used in the field of airbag inflators, can also be used, but the number of oxygen in nitrite molecule is reduced or released out of the bag as compared with nitrate. Nitrate is preferable from the viewpoint of reducing generation of fine powdery mist, which is liable to occur.

The function of the slag-forming agent is from a liquid state in order to prevent the oxide of an alkali metal or an alkaline earth metal produced by the decomposition of the oxidizer component in the gas generant composition from being discharged as a mist to the outside of the inflator. It has the function of changing to a solid state and stopping it in the combustion chamber, and it is possible to select an optimized slag forming agent depending on the difference in metal components.
Naturally occurring clay mainly composed of aminosilicates such as bentonite and kaolin, artificial clay such as synthetic mica, synthetic kaolinite and synthetic smectite, and talc which is one of hydrous magnesium silicate minerals. A slag forming agent selected from at least one kind can be used. Acid clay can be mentioned as a preferable slag forming agent.

For example, the viscosity and melting point of the oxidation mixture in the ternary system of calcium oxide generated from calcium nitrate, aluminum oxide which is the main component in clay, and silicon oxide are in the range of 1350 ° C. to 1550 ° C. depending on the composition ratio. The viscosity changes from 3.1 poise to about 1000 poise, and the melting point changes from 1350 ℃ to 1450 ℃ depending on the composition. By utilizing these properties, the slag-forming ability can be exhibited according to the mixed composition ratio of the gas generant composition.

The amount of the slag forming agent used can be varied within the range of 1 to 20% by weight, but is preferably within the range of 3 to 7% by weight. If the amount is too large, the linear burning rate and the gas generation efficiency are lowered, and if the amount is too small, the slag-forming ability cannot be sufficiently exhibited.

The binder is an essential component for obtaining a molded product of the desired gas generant composition, exhibits a viscosity in the presence of water, a solvent, etc. and does not have a significant adverse effect on the combustion behavior of the composition. Any of them can be used, and examples include polysaccharide derivatives such as metal salts of carboxymethyl cellulose, hydroxyethyl cellulose, cellulose acetate, cellulose propionate, cellulose acetate butyrate, nitrocellulose, and starch, but they are safe in production and easy to handle. Therefore, a water-soluble binder is preferable. The most preferred example is a metal salt of carboxymethyl cellulose, particularly a sodium salt.

The binder may be used in an amount of 3 to 12% by weight, more preferably 4 to 12% by weight. The larger the amount, the stronger the fracture strength of the molded body, but the larger the amount, the greater the number of carbon elements and hydrogen elements in the composition, and a trace amount of CO, which is an incomplete combustion product of carbon elements.
This is not preferable because the gas concentration increases and the quality of the generated gas deteriorates. In particular, if the amount exceeds 12% by weight, it is necessary to increase the relative proportion of the oxidant, and the relative proportion of the gas generating compound decreases, making it difficult to establish a practical inflator system.

Further, as a side effect of the sodium salt of carboxymethyl cellulose, oxidation is caused by the presence of a molecular-order micro-mixing state of sodium nitrate produced by a metal exchange reaction with a nitrate during the production of a molded body using water as described below as a side effect. Nitrate as an agent, especially shift the decomposition temperature of strontium nitrate, which has a high decomposition temperature, to a lower temperature side,
It has the effect of improving flammability.

Accordingly, the preferred gas generant composition used in the practice of the present invention is: (a) about 25-60% by weight, preferably 30-40% by weight nitroguanidine (b) about 40-65% by weight. %, Preferably 45-65% by weight of oxidant (c) about 1-20% by weight, preferably 3-7% by weight of slag-forming agent (d) about 3-12% by weight, preferably 4-12% by weight. A particularly preferred composition is a gas generant composition comprising a binder of (a) about 30-40% by weight nitroguanidine (b) about 40-65% by weight strontium nitrate (c) about 3-7. A gas generant composition comprising, by weight, acid clay and (d) about 4-12% by weight sodium salt of carboxymethyl cellulose.

Thus, according to the present invention, (a) about 25-60% by weight nitroguanidine (b) about 40-65% by weight oxidizing agent (c) about 1-20% by weight slag forming agent. (D) A gas generant molding for an air bag is provided, which is obtained by molding a composition having a linear burning rate of 1 to 12.5 mm / sec, which is composed of about 3 to 12% by weight of a binder, into a single-hole cylindrical shape.

Dicyandiamide is also preferably used as the nitrogen-containing organic compound. The amount of the nitrogen-containing organic compound used in the gas generating composition varies depending on the number and molecular weight of the elements constituting the nitrogen-containing compound used, the combination with the oxidizing agent and other additives, but the addition of the oxidizing agent and other additives. The oxygen balance due to the combination with the agent is most preferably around zero, but the optimum composition molded body can be obtained by adjusting the oxygen balance to the positive side or the negative side according to the above-mentioned generation concentration of trace amounts of CO and NO _x . For example, when dicyandiamide is used, its amount is preferably in the range of 8 to 20% by weight.

As the oxygen-containing oxidizing agent used in the present invention, an oxidizing agent known in the field of gas generating agents for airbags can be used, but basically, the residual component becomes liquid or gas, It is preferable to use an oxidant having a property of forming a high-melting point substance so that the thermal load on the coolant and the filter agent can be reduced.

For example, potassium nitrate is an oxidizing agent generally used as a gas generating agent, but the main residual component at the time of combustion is potassium oxide or potassium carbonate, and potassium oxide is converted to potassium peroxide at about 350.degree. It decomposes to metallic potassium, and further, potassium peroxide has a melting point of 763 ° C. and becomes a liquid or a gaseous state when the gas generator is in operation, which is not preferable in view of the thermal load on the coolant and filter agent.

Specific examples of the oxidizing agent preferably used in the present invention include strontium nitrate. The main residual component of strontium nitrate during combustion is strontium oxide with a melting point of 2430 ° C, which is almost solid even when the gas generator is operating.

The amount of the oxidizing agent used in the present invention is not particularly limited as long as it is an amount of the oxidizing agent sufficient to completely burn the nitrogen-containing organic compound, and can be appropriately changed to control the linear burning rate and the calorific value. When strontium nitrate is used as an oxidizing agent for dicyandiamide, the amount is preferably 11.5 to 55% by weight.

One of the preferred gas generant compositions of the present invention is 8 to 20% by weight of dicyandiamide, 11.5 to 55% by weight of strontium nitrate and 24.5 to 80% of copper oxide.
Wt%, sodium salt of carboxymethyl cellulose
The content of the dicyandiamide is 8 to 20% by weight, strontium nitrate is 11.5 to 55% by weight, and copper oxide is 24.5 to 80% by weight.
It also provides a gas generant composition containing 0.5 to 8% by weight of sodium salt of carboxymethyl cellulose.

Generally, in order to mold the explosive composition to a specific thickness using a binder, conventionally known methods such as tablet molding and extrusion molding can be applied.
When used as a gas generating agent for an air bag as in the present invention, in view of linear burning velocity, it is preferable to make a relatively thin molded body, and in order to have necessary strength, the molded body is It is preferable to mold into a single-hole cylindrical shape, and to perform this molding by applying a drawing method.

In the present invention, the above gas generant composition is dry-mixed, then water is added and the mixture is slurry-mixed until it is sufficiently uniform, and the mixture is molded using a companding machine equipped with a mold to obtain an appropriate length. By cutting into small pieces and drying, a molded product of a gas generant having sufficient performance applicable to an airbag system was obtained.

The gas generating agent can be processed into a single-hole cylindrical shape as shown in FIG. 1 by cutting into an appropriate length after the drawing. Further, in the drawing method, it is possible to adjust the thickness by using a mold and keeping the outer diameter constant and changing the inner diameter.

With such a shape, heat generation can be suppressed and combustion can be performed from the outer surface and the inner surface of the cylinder, and an excellent linear burning rate sufficient for application to an airbag can be obtained. The outer diameter (R), the inner diameter (d), and the length (L) of the single-hole cylindrical molded body can be appropriately set within a range where it can be applied to a gas generator, but in consideration of practicality and burning speed, It is desirable that the diameter is 6 mm or less and the ratio of the length to the thickness W = (R−d) / 2 (L / W) is 1 or more. Conventionally, a molded article having such a shape has been known in the fields of propellant and propellant, but there is no example applied to a gas generating agent for an airbag. When the molded product of the present invention is used, it burns within a desired burning time even when the linear burning speed is small, and by using a slag forming agent together, an additional component for heat removal is not required, and gas is generated. The vessel itself can be miniaturized.

A preferred embodiment of the manufacturing method for obtaining the molded product used in the present invention will be described below. First, depending on the particle size and bulk density of the raw material, a composition mass is prepared by a kneading operation using 10 to 30% of water in an amount that is the outer amount of the desired final gas generant composition. The order of mixing is not particularly specified and may be the order that is most safe in manufacturing. Then, after optionally removing excess water, the composition mass is passed through a mold having a certain shape to form a single-hole cylindrical shape, usually 40 to 80 kg / cm ² , depending on the case.
Extrude under pressure conditions of 130-140 kg / cm ² to make a single-hole cylindrical string. Further, before the surface of the cord-like body is dried, it is cut into a desired length by a cutting machine and then dried to obtain a desired molded body. The linear burning rate of the gas generant composition is derived by burning in a vessel with a capacity of 1 liter and having a nitrogen replaced under a pressure of 70 kgf / cm ² and analyzing the pressure variation in the vessel recorded by a pressure sensor. .

The shape of the molded article is determined by the linear burning rate of the final composition. For compositions with linear burning rates of around 10 mm / sec and below, the outer diameter is 1.5 to 3 mmφ and the length is 0.5.
It is preferable to use a single-hole cylindrical molded body having a size of 5 mm. In particular, in the composition comprising 35% by weight of nitroguanidine, 50% by weight of strontium nitrate, 5% by weight of acid clay and 10% by weight of sodium salt of carboxymethyl cellulose, the outer diameter is
2.2 to 2.75 mmφ, inner diameter 0.56 to 0.80 mmφ, length 2.5 to 3.2 m
It is preferable to use a single-hole cylindrical molded body of m 2.

The present invention further includes: (A) about 25-60 wt% nitrogen-containing organic compound (b) about 40-65 wt% oxidizer (c) about 1-20 wt% slag forming agent (d) about 3-12 wt% binder A composition comprising B. Water or a solvent is added, and a kneading operation is performed to form a composition mass. Extruding the composition mass through a mold under pressure conditions into a single-hole cylinder, D. The present invention also provides an inflator system using a cut and dried molded article of a gas generating agent for an airbag.

When the gas generant composition according to the present invention is used as an inflator system, there is no particular limitation,
The most suitable combination is one having an inflator structure in which the characteristics of the gas generant composition are utilized.

[0043]

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these examples.

Example 1 To 35 parts of high specific gravity nitroguanidine (hereinafter abbreviated as NQ) (hereinafter, “parts” means “parts by weight”), 15 parts of water based on the total amount of the composition was added and mixed and kneaded. To do. Separately, 50 parts of strontium nitrate, 5 parts of acid clay and 10 parts of sodium salt of carboxymethyl cellulose are dry mixed, added to the above-mentioned wet mixed powder, and further kneaded. Then add the kneaded mixture to the outer diameter
Pressure of 80 kg / cm ² through a mold with a diameter of 2.5 mm and an inner diameter of 0.80 mm
Extruded under the pressure condition of 1. to make a single-hole cylindrical string-like body. Furthermore, this string-shaped body was cut into a length of 2.12 mm by a cutting machine,
The water was sufficiently dried to obtain a gas generant molding. The results of a 60 liter tank test at room temperature using 38 g of this gas generating agent molded product are shown below. The linear burning rate of this gas generant composition was 8.1 mm / sec. Tank maximum pressure
The pressure was 1.83 kg / cm ² and the maximum pressure arrival time was 55 milliseconds. Further, the amount of mist in the tank was 700 mg or less, the inside of the tank was very clean, and the gas concentrations of trace amounts of CO and NO _x were within the values required by the automobile manufacturer.

Examples 2 to 4 , A and Comparative Examples 1 to 2 A gas generant composition molded body was prepared in the same manner as in Example 1 except that the parts by weight of each component or the shape of the molded body was changed as shown in Table 1. made.

[0046]

[Table 1]

The linear heating rate of each of the gas generant compositions of Examples 1 to 4 and A and Comparative Examples 1 and 2 and the total calorific value when the composition amount required to generate a constant gas generation amount were used. The results are shown in Table 2.

[0048]

[Table 2]

The results of the tank test are shown in Table 3.

[0050]

[Table 3]

Example 5 12 parts of dicyandiamide, 53 parts of strontium nitrate, 30 parts of copper oxide and 5 parts of carboxymethyl cellulose sodium salt were dry-mixed well, and 12.5 parts of water was further added to the mixture until the mixture was sufficiently homogeneous. I went. After mixing the slurry, using a companding machine equipped with a die having an outer diameter of 1.6 mmφ and an inner diameter of 0.56 mmφ, companding was performed at a molding pressure of 60 to 70 kgf / cm ² and a companding speed agent of 0.2 cm / min. It was cut to a length of about 5 mm. After cutting, it was dried at 50 ℃ for 15 hours or more, and the gas generant composition (linear burning rate 7.4mm / sec, total calorific value 22.2Kcal)
And A gas generant composition was obtained with a weight yield of 80% or more. A predetermined tank test (method described in JP-B-52-3620 and JP-B-64-6156) was conducted using 54 g of this gas generating composition. A tank pressure of 1.22 kg / cm ² and a maximum pressure arrival time of 50 msec were obtained, which was within a desired range for practical use without damaging the metal heat removal agent and the filter.

Example 6 Except for 10 parts of dicyandiamide, 35 parts of strontium nitrate, 50 parts of copper oxide and 5 parts of carboxymethyl cellulose sodium salt, the addition amount was changed to 65 g, and the weight of the composition was changed to 65 g. A gas generant composition was produced (linear burning rate: 7.6 mm / sec, total calorific value: 22.1 Kcal), and a tank test was conducted in the same manner as in Example 5. A tank pressure of 1.31 kg / cm ² and a maximum pressure arrival time of 55 msec were obtained, which was within a desired range for practical use without damaging the metal heat removal agent and the filter.

Example 7 A gas generant composition was produced in the same manner as in Example 5 except that the addition amount was changed to 13 parts of dicyandiamide, 32 parts of strontium nitrate, 50 parts of copper oxide, and 5 parts of sodium carboxymethyl cellulose sodium salt, and an outer diameter was obtained. 1.15mmφ, inner diameter 0.34mmφ, length 0.52mm
Molded into. Linear burning rate 6.1mm / sec, total calorific value 22.2Kca
l). Using 67 g of this molded product, a tank test was conducted in the same manner as in Example 5. A tank pressure of 1.67 kg / cm ² and a maximum pressure arrival time of 47 msec were obtained, and a wider range of performance adjustable range was obtained without damaging the mold heat removal agent and the filter.

Comparative Example 3 Slurry mixing was carried out with the same composition as in Example 5, and after mixing the slurry, it was molded into a flaky pellet with a diameter of 5 mmφ and a thickness of 1 mm using a conventional key-press molding machine. The weight yield of the pellets was 20% or less, and the pellets did not show practical strength.

Comparative Example 4 Powder of 23 parts of dicyandiamide, 57 parts of strontium nitrate and 20 parts of copper oxide was added to 10 parts of water and mixed sufficiently, and after conditioning the humidity, a diameter of 5 mmφ and a thickness of 2 mm was obtained by a conventional key press molding machine. Molded into thin pellets (linear burning rate 24.0 mm / sec, total calorific value 2
8.6Kcal). A tank test was conducted in the same manner as in Example 5 using 50 g of the composition, but the desired tank pressure could not be obtained because the filter was seriously damaged.

Comparative Example 5 Pellets were molded in exactly the same manner as in Comparative Example 1 except that 19 parts of dicyandiamide, 31 parts of potassium nitrate and 50 parts of copper oxide were used (linear burning rate 9.1 mm / sec, total calorific value 25.3 Kcal). A tank test was conducted in the same manner as in Example 5 using 60 g of the molded body. The combustion completion time was 100 msec or more, and the practical performance could not be satisfied.

Table 4 shows the total calorific value when the linear burning rate of each of the gas generant compositions of Examples 5 to 7 and the amount of the composition required to generate a constant gas generation amount were used.

[0058]

[Table 4]

[0059]

EFFECTS OF THE INVENTION According to the present invention, a gas generant composition which has a low linear burning rate and could not provide satisfactory performance while being paid attention to from the viewpoint of safety, is a gas showing a low calorific value and a high burning performance. A novel gas generating agent composition for an air bag, which can be formed into a generating agent molded article and contains a nitrogen-containing organic compound and an oxidizing agent, and a molded article using the same are provided. INDUSTRIAL APPLICABILITY The present invention paves the way for downsizing gas generators and applying them to airbag systems.

[Brief description of drawings]

FIG. 1 shows an appearance of a gas generating agent molded body for an air bag of the present invention, L means length, R means outer diameter, and d means inner diameter.

Continuation of the front page (72) Inventor Takushi Yokoyama 3-12-2 Kitashinoka, Himeji City, Hyogo Prefecture (72) Naoki Matsuda Inventor, Naoki Matsuda 500-3-343 (56) Kamioumabe, Yobu District, Himeji City, Hyogo Pref. 7-206570 (JP, A) JP-A-6-92769 (JP, A) JP 60-9994 (JP, B2) US Patent 5125684 (US, A) European publication 659715 (EP, A1) International publication 94 / 8918 (WO, A1) International publication 95/4710 (WO, A1) International publication 95/4016 (WO, A1) International publication 95/9825 (WO, A1) (58) Fields investigated (Int.Cl. ⁷ , DB) Name) C06D 5/00 B01J 7/00 B60R 21/26 C06B 31/00 C06B 43/00

Claims (11)

(57) [Claims] 1. A gas generant composition containing a nitrogen-containing organic compound excluding azide and having a linear burning rate in the range of 5 to 12.5 mm / sec under a pressure of 70 kgf / cm ^{2 in} the form of a single-hole cylinder. molded gas-generating agent for an air bag ing and molding
Karadadea is, the thickness W of the single-hole cylindrical molded body, W = (R-d) / 2 (R
Is the outer diameter, d is the inner diameter) , and the linear burning velocity r (mm / sec) of the gas generating composition under a pressure of 70 kgf / cm ² and the thickness W of the single-hole cylindrical molded body. (M
m) is a gas generating agent molded article for an air bag having a range of 0.005 ≦ W / (2 · r) ≦ 0.1. 2. The linear burning velocity r (mm / sec) and single hole
The relationship with the thickness W (mm) of the cylindrical molded body is 0.033 ≦
2. A range represented by W / (2 · r) ≦ 0.1.
The gas generating agent molding for an airbag as described. 3. The molded product of a gas generating agent for an air bag according to claim 1 or 2, wherein the ratio of the length to the thickness of the single-hole cylindrical molded product is 1 to 9.62. 4. The single-hole cylindrical molded body has a length of 0.5 to 5 m.
The gas generating agent molded body for an air bag according to any one of claims 1 to 3, wherein m is m. 5. The outer diameter of the single-hole cylindrical molded body is 1.15-6.
The molded product of the gas generating agent for an air bag according to any one of claims 1 to 4, which has a size of mm. 6. The gas generating agent for an air bag according to claim 1, wherein the gas generating composition comprises a nitrogen-containing organic compound, an oxidizing agent, and a binder and, if necessary, a slag forming agent. Agent molded body. 7. The gas generating composition comprises (a) 25 to 60% by weight of a nitrogen-containing organic compound, (b) 40 to 65% by weight of an oxidizing agent, (c) 1 to 20% by weight of a slag forming agent, and (d). 7. The gas generant molded article for an air bag according to claim 6, which comprises 3 to 12% by weight of a binder. 8. The nitrogen-containing organic compound is nitroguanidine,
8. The molded product of a gas generating agent for an air bag according to claim 6 or 7, wherein the oxidizing agent is strontium nitrate, the binder is carboxymethyl cellulose sodium salt, and the slag forming agent is acid clay. 9. The gas generant composition comprises (a) 25 to 60% by weight of nitroguanidine and (b) strontium nitrate 4
0-65% by weight, (c) acid clay 1-20% by weight,
(D) Carboxymethyl cellulose sodium salt 3-1
The gas generating agent molded body for an air bag according to any one of claims 1 to 8, which comprises 2% by weight. 10. The molded product of a gas generating agent for an air bag according to claim 6, wherein the nitrogen-containing organic compound is dicyandiamide, the oxidizing agent is strontium nitrate and copper oxide, and the binder is carboxymethyl cellulose sodium salt. 11. 8 to 20% by weight of dicyandiamide,
The molded product of a gas generating agent for an air bag according to claim 10, which contains 11.5 to 55% by weight of strontium nitrate, 24.5 to 80% by weight of copper oxide, and 0.5 to 8% by weight of sodium carboxymethyl cellulose.