JP2960388B2 - Molded product of gas generating composition 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 molded article of a gas generating composition which burns and supplies a gas component to inflate an air bag system, and a gas generator system for an air bag using the molded article. More specifically, the present invention relates to a novel molded article of a gas generating composition serving as a working gas in an airbag system provided for protecting a human body mounted on an automobile, an aircraft, and the like, and an air using the molded article. The present invention relates to a gas generator system for a bag.

[0002]

2. Description of the Related Art When a vehicle such as an automobile collides at a high speed, an occupant crashes into a hard part inside the vehicle, such as a steering wheel or a front glass, due to inertia, resulting in injury or death. To prevent this, airbag systems have been developed that rapidly inflate the bag with gas to prevent occupants from hitting dangerous places. The requirements for a gas generating agent used in this airbag system are that the inflation time of the bag is very short, usually within 40 to 50 milliseconds, and that the atmosphere in the bag is harmless to the human body, that is, the air composition in the car is reduced. It is very severe such as being close.

At present, as a gas generating base generally used for an air bag system, an inorganic azide compound, particularly sodium azide can be mentioned. Sodium azide is excellent in terms of flammability, but an alkali component by-produced during gas generation is toxic, and does not satisfy the above requirements in terms of safety for passengers. Also,
Since the substance itself is toxic, there is a concern about the environmental impact of disposal.

[0004] In order to compensate for these drawbacks, some so-called non-azide gas generating agents have been developed in place of sodium azide. For example, JP-A-3-2088878 discloses a composition containing, as main components, tetrazole, triazole or a metal salt thereof and an oxygen-containing oxidizing agent such as an alkali metal nitrate. In addition,
JP-A-6156 and JP-B-64-6157 disclose a gas generating agent containing a metal salt of a bitetrazole compound containing no hydrogen as a main component.

Further, Japanese Patent Publication No. 6-57629 discloses a gas generating agent containing a transition metal complex of tetrazole and triazole. JP-A-5-254977 discloses a gas generating agent containing triaminoguanidine nitrate, JP-A-6-239683 discloses a gas generating agent containing carbohydrazide, and JP-A-7-61885 discloses acetic acid. A gas generant comprising cellulose and a nitrogen-containing non-metallic compound such as nitroguanidine is disclosed. Further, U.S. Pat. No. 5,125,684 discloses the use of nitroguanidine as an energetic material coexisting with 15-30% of a cellulosic binder. Also, Japanese Patent Application Laid-Open No. 4-2
No. 65292 discloses a gas generating composition in which a tetrazole or triazole derivative is combined with an oxidizing agent and a slag forming agent.

[0006] Regarding the gas generation behavior and the bag inflation behavior according to these prior arts, the seating position of the occupant is relatively fixed particularly on the driver's seat (hereinafter abbreviated as D seat) side, so that the conventional inflation behavior performance is sufficiently safe. Has been believed to be. However, as the airbag system is widely used and becomes closer to the standard equipment, there are hundreds of people with high or low sitting height, people who are holding on to the steering wheel, etc. There are various types of seats (hereinafter abbreviated as P seats), such as when a child or the like is to be boarded, and thus there has been a demand for the development of a safer airbag system.

[0007] That is, although it is possible to use the conventional inflation behavior performance, in order to make the airbag system safer, the initial inflation speed, for example, from the start of gas generation on the D seat side.
The expansion rate during 10 milliseconds is made slower than before,
Eliminate the damage caused by the momentum of the initial bag inflation and 30
A technique for maintaining sufficient occupant restraint after 50 to 50 milliseconds has been desired, and a technique for similarly controlling the gas generation behavior on the P seat side has been desired.

[0008] As such a technique, Japanese Patent Application Laid-Open No. 8-207 is disclosed.
No. 696 discloses a technique in which gas is generated in two stages, the bag is inflated relatively slowly in the initial stage of operation, and gas is rapidly generated in the second stage. However, in this type of technology, the structure inside the gas generator is complicated, the size of the container is increased, and at the same time, the cost is increased. As described above, the prior art in which the gas generating behavior is controlled by the gas generant composition molded body alone, and as a result, the inflation rate of the bag is controlled has not been disclosed yet, and the gas has a simple structure and low cost. There is a long-felt need for a technique capable of controlling the gas generation behavior using only the molded article of the generator composition.

[0009]

The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, by controlling the physical shape of the molded article of the gas generating composition to a predetermined shape, the above-mentioned problems have been solved. Have been found to be able to solve the problem, and have completed the present invention.

The molded article of the gas generating composition for an airbag of the present invention has a physical shape such that a desired tank maximum pressure is P (kPa) in a tank combustion test using a gas generator using the molded article. When the time from the start of pressure rise to the maximum tank pressure P (kPa) is T milliseconds, 0.25 x T
The tank pressure after millisecond is adjusted to be 0.25 × P (kPa) or less. Preferably, in the tank combustion test, the tank pressure after 0.80 × T milliseconds is 0.70 × P (k
It has been adjusted to be Pa) or more.

Accordingly, the present invention relates to a molded article of a gas generating composition for an airbag, wherein a desired tank maximum pressure is set to P in a tank combustion test by a gas generator using the molded article.
(kPa), tank maximum pressure P from start of tank pressure rise
(kPa), the tank pressure after 0.25 × T milliseconds is 0.25 × P (kPa) or less, preferably T milliseconds,
A gas generating agent composition for an air bag, wherein the tank pressure after 0.80 × T milliseconds is adjusted to be 0.70 × P (kPa) or more, more preferably 0.20 × P (kPa) or less. A molded article, particularly a molded article made of a non-azide-based gas generating composition, which is porous, the length of one porous molded article is L (mm), The inner diameter of d
(Mm), wherein the value of d is 0.2 to 1.5 (mm) and the value of L / d is 3.0 or more, which provides a molded article of the gas generating composition for an airbag. It is.

Here, the term "porous" means a state in which a through-hole exists in the molded article of the gas generating agent. The number of holes per molded article may be one or more. When the number of holes is one, it has a single hole shape.

Further, the present invention relates to a gas generator system for an air bag using such a molded body, wherein a desired tank maximum pressure is set to P (k) in a tank combustion test using the gas generator.
Pa), tank maximum pressure P (kP
a) When the time to reach is T milliseconds, the tank pressure after 0.25 x T milliseconds is 0.20 x P (kPa) or less, and 0.80 x
An object of the present invention is to provide a gas generator system for an air bag, wherein a tank pressure after T milliseconds is 0.70 × P (kPa) or more.

A gas generator using the molded article of a gas generating composition for an air bag according to the present invention has a housing having a plurality of gas outlets, an igniting means provided in the housing, and the igniting means. A gas generator having gas generating means for generating a combustion gas by being ignited by a gas generator, and a combustion chamber accommodating the gas generating means.
In the tank combustion test using the gas generator, when the desired tank maximum pressure is P (kPa) and the time from the start of tank pressure rise to the tank maximum pressure P (kPa) is T milliseconds, 0.25 × T milliseconds The subsequent tank pressure is 0.25 × P (kPa) or less. In the tank combustion test, preferably the tank pressure after 0.80 × T milliseconds is 0.70 ×
P (kPa) or more and the tank maximum pressure P (kPa) is 110 ~ 22
0 (kPa), and the time T from the start of tank pressure rise to the maximum tank pressure P (kPa) is 30 to 65 milliseconds.

In the present invention, the tank combustion test is a test conducted by the following method. <Tank combustion test> An inflator filled with a molded article of a gas generating agent was fixed in a SUS (stainless steel) tank having an inner volume of 60 liters. After sealing the tank at room temperature, it was connected to an external ignition electric circuit. Using a pressure transducer separately installed in the tank, the time at which the ignition electric circuit switch is turned on is set to 0, and the change in pressure rise in the tank is measured for a time of 0 to 200 milliseconds. Each measurement data is finally processed as a tank pressure / time curve by computer processing.
A curve for evaluating the performance of the gas generating agent molded product is obtained. After the completion of combustion, a part of the gas in the tank is extracted and used for gas analysis such as CO and NOx.

The tank maximum pressure in the present invention refers to the maximum pressure in the SUS tank in this tank combustion test.

[0017]

Embodiments of the present invention will be described below in detail.

The molded article of the gas generating composition for an airbag of the present invention has a tank maximum pressure of P (kPa) in a tank combustion test by a gas generator using the molded article. When the time until the maximum pressure P (kPa) is reached is T milliseconds, the tank pressure after 0.25 × T milliseconds is adjusted to 0.25 × P (kPa) or less, preferably 0.20 × P (kPa) or less. It is characterized by the following. Further, it is preferable that the tank pressure after 0.80 × T milliseconds is adjusted to be 0.70 × P (kPa) or more.

The tank pressure after 0.25 × T milliseconds is 0.20 × P (k
Exceeding Pa), especially exceeding 0.25 × P (kPa), the momentum of the initial bag inflation becomes too large. Further, if the tank pressure after 0.80 × T milliseconds is set to 0.70 × P (kPa) or more, the safety of the occupant in the event of a collision of an automobile or the like can be more reliably ensured.

Although the molded article of the present invention has the above-mentioned characteristics, one of the characteristics of the physical shape is that it is porous, and the value of the inner diameter d of the hole is 0.2 to 1.5 (mm). The ratio of the inner surface area that initially ignites out of the total inner surface area of the inner diameter portion when the perforated molded body is ignited by the thermal energy of the ignition system is controlled by being within the range and the value of L / d being 3.0 or more. It is doing. The part that is not ignited in the early stage immediately shifts to the ignited state due to the amount of heat generated in the ignited part. Therefore, only the initial ignition stage can be controlled without a time delay until the maximum pressure is reached. It should be recognized that the technique of the present invention is fundamentally different from the so-called depower technique in which the overall gas generation output is slightly reduced and the initial stage is controlled in this regard.

Accordingly, the perforated molded article of the present invention may be in a single-hole state, or may be formed in a small single-hole state as long as the result relating to the above control can be obtained as a result. Although it does not matter, a single hole state is preferred from the viewpoint of molding cost. The value of the inner diameter d of the hole is 0.2-1.5 mm, preferably 0.4-1.0 mm. If the value of d is less than 0.2 mm, the initial ignition area on the inner surface of the perforated molded body due to the heat energy of the ignition system is insufficient, and the desired result cannot be obtained.
If it exceeds mm, thermal energy reaches the entire inner surface of the perforated molded body, and as a result, the initial ignition combustion area increases and a desired gas generation output cannot be obtained.

The value of L / d of the perforated molded article of the present invention is 3.0 or more. However, if L is too long, the filling efficiency in a desired gas generating vessel is reduced. It should be determined according to the size, and a preferable range of the value of L / d is 3.0 to 10.0. If the value of L / d is less than 3.0, the gas generation behavior cannot be controlled as described above.

The length L of the perforated molding of the present invention is not particularly limited, but is preferably 1.5 to 30 mm. The outer diameter D is also not particularly limited, but is 1.5 to 5.0 mm, 2.0 to
5.0 mm or 2.4 to 5.0 mm is preferred.

The molded article of the gas generating composition of the present invention may have a plurality of through holes. In this case, the arrangement of the through holes is not particularly limited. In a preferred embodiment, the through holes are arranged in an attempt to stabilize gas generator performance.

The two or more holes arranged in the cross section of the cylindrical molded body are the distance between the centers of two mutually adjacent holes and the distance between the center of these two holes and the outer end of the molded body. Are desirably arranged to be substantially equal.

In a preferred embodiment, as shown in FIG. 3, seven through holes are formed in a cylindrical molded body having a circular cross section. Of these through holes, the center of one hole is arranged at the center of the circle of the molded body, and the other six holes are arranged around the center hole. In FIG. 3, the distance (b) between the centers of each of the two holes arranged in the periphery and the distance (c) between the center of these two holes and the outer end of the molded body are equal, respectively.
Further, the distance (a) between the center of the center hole and each center of the holes arranged in the periphery is equal to each other. It is desirable that the equilateral triangle composed of (a), (b) and (a) and the equilateral triangle composed of (b), (c) and (c) are substantially identical to each other. Six equilateral triangles are arranged from one central hole, and the centers of the six surrounding holes are arranged at the vertices of the equilateral triangle.

As another example of a molded body, the central hole can be surrounded by 18 peripheral holes. This number of holes and arrangement can be as advantageous as above.
The number and arrangement of these holes are determined by the ease of manufacturing the gas generating agent and the balance between manufacturing cost and performance, and are not particularly limited.

In this case, the outer diameter D of the porous molded body is 4
~ 50mm, each through hole d is 0.4 ~ 1.0mm, length L is 1.5 ~ 30m
m is preferred. The number of through holes is preferably seven, but the number of holes is not limited as long as each hole has the above arrangement.

An example of evaluation of a gas generator incorporating a molded body molded in this shape in a 60-liter tank in an atmosphere of 20 ° C. is shown below. Here, the outer diameter D of the molded body is 6.5 mm, the length L is 4 mm, and the hole diameter is about 0.7 mm. The tank output curve is shown in FIG. At this time, the inflection point of the tank curve appears at this position by adjusting the internal pressure of the housing to reach the maximum value 10 to 35 msec after the application of the ignition current, and the effect of the gas generator which reduced the influence on the occupant in the early stage of the back deployment It becomes a compact.

Next, a preferred embodiment of the method for producing a perforated molded article of the present invention will be described. First, depending on the particle size and bulk density of the raw material, a mass of the gas generating composition is formed by a kneading operation using a solvent that dissolves the binder. The solvent should be one which dissolves the binder and is suitable for molding. For a water-soluble binder, water can be used, and for an organic-soluble binder, an organic solvent such as ether, ethyl acetate or acetone can be used. The amount of the solvent to be used is a concentration suitable for molding a desired composition, and generally, an amount of about 10 to 30% by weight as an external part of the amount of the final gas generating composition is preferable. The order of mixing is not particularly specified, and may be the order in which the safest production is maintained. Then, optionally after removing excess solvent, the composition mass is passed through a mold having a single-hole cylindrical shape, usually 40 to 80 kg / cm ² , and optionally 130 to 140 kg / cm ² .
Extrusion is performed under a pressurized condition of cm ² to form a single-hole cylindrical string. Further, before the surface of the cord is dried, the cord is cut into a desired length so that the value of L / d becomes 3.0 or more by a cutting machine, and then dried to obtain a desired molded body. it can.

Next, the non-azide gas generating composition used in the present invention will be described.

The non-azide gas generating composition used in the present invention preferably comprises a nitrogen-containing compound, an oxidizing agent, a slag forming agent and a binder.

Examples of the nitrogen-containing compound used in the present invention include one or a mixture of two or more selected from the group consisting of a triazole derivative, a tetrazole derivative, a guanidine derivative, an azodicarbonamide derivative, and a hydrazine derivative. Specific examples of these include 5-oxo-1,2,4-triazole, tetrazole, 5-aminotetrazole, 5,5′-bi-1H-tetrazole, guanidine, nitroguanidine, cyanoguanidine, triaminoguanidine nitrate, Examples thereof include guanidine nitrate, guanidine carbonate, biuret, azodicarbonamide, carbohydrazide, carbohydrazide nitrate complex, oxalic acid dihydrazide, and hydrazine nitrate complex.

Among these nitrogen-containing compounds, one or more selected from the group consisting of a tetrazole derivative and a guanidine derivative are preferable, and in particular, nitroguanidine,
Cyanoguanidine and 5-aminotetrazole are preferred, and nitroguanidine is most preferred in view of the small number of carbon atoms in the molecule. There are two types of nitroguanidine: needle-shaped crystalline nitroguanidine with low specific gravity and high specific gravity nitroguanidine with bulk crystals.Either of them can be used. The use of guanidine is more preferred.

The mixing ratio of the nitrogen-containing compound in the gas generating composition according to the present invention varies depending on the number of carbon elements, hydrogen elements and other oxidized elements in the molecular formula, but is usually 25 to 56% by weight. The range is preferred, with a range of 30 to 40% by weight being particularly preferred. Depending on the type of the oxidizing agent in the gas generating composition, the absolute value of the mixing ratio of the nitrogen-containing compound varies,
When the amount is more than the theoretical amount of complete oxidation, the concentration of trace CO in the generated gas increases, and when the amount is less than the theoretical amount of complete oxidation, the concentration of trace NOx in the generated gas increases. Therefore, the range in which the optimum balance between the two is maintained is most preferable.

Various oxidizing agents can be used as the oxidizing agent used in the gas generating composition according to the present invention, and the oxidizing agent is selected from at least one of nitrates containing a cation selected from alkali metals or alkaline earth metals. Oxidants are preferred. An oxidizing agent other than nitrate, that is, an oxidizing agent widely used in the field of airbag inflators such as nitrite and perchlorate may also be used, but the number of oxygen in nitrite molecules is reduced as compared to nitrate, or the amount outside the bag is reduced. Nitrate is preferred from the viewpoint of, for example, reducing the generation of fine mist that is easily released to the air. Examples of the nitrate containing a cation selected from alkali metals or alkaline earth metals include sodium nitrate, potassium nitrate, magnesium nitrate, strontium nitrate, and the like, with strontium nitrate being particularly preferred.

The mixing ratio of the oxidizing agent in the gas generating composition according to the present invention varies in absolute value depending on the kind and amount of the gas generating compound used, but is preferably in the range of 40 to 65% by weight. A range of 45 to 60% by weight, relative to the NOx concentration, is preferred.

The function of the slag forming agent in the gas generating composition according to the present invention is as follows. It is a function to change from a liquid state to a solid state and stop it in the combustion chamber in order to avoid discharge to the outside of the inflator. It is possible to select a slag forming agent optimized by a difference in metal components. Specific examples of slag forming agents include acid clay, silica, bentonite, naturally occurring clay mainly containing aluminosilicates such as kaolin, and synthetic clays such as synthetic mica, synthetic kaolinite, and synthetic smectite; A slag-forming agent selected from at least one kind of hydrated magnesium silicate mineral, such as talc, is preferred. Among these, acidic clay or silica is preferred, and acidic clay is particularly preferred.

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

The blending ratio of the slag forming agent in the gas generating composition according to the present invention can be changed within a range of 1 to 20% by weight, and is preferably within a range of 3 to 10% by weight. If the amount is too large, the linear burning rate and the gas generation efficiency will decrease. If the amount is too small, the slag forming ability cannot be sufficiently exhibited.

In the gas generating composition according to the present invention, the binder is an essential component for obtaining a desired molded product, and exhibits a viscosity in the presence of water, a solvent, etc., and has a significant adverse effect on the combustion behavior of the composition. Can be used as long as it does not give the. Specific examples of the binder used in the present invention include polysaccharide derivatives such as metal salts of carboxymethylcellulose, hydroxyethylcellulose, cellulose acetate, cellulose propionate, cellulose acetate butyrate, nitrocellulose, and starch. A water-soluble binder is preferable from the viewpoint of easy handling and
A metal salt of carboxymethyl cellulose, particularly a sodium salt, is mentioned as the most preferred example.

The mixing ratio of the binder in the gas generating composition according to the present invention is preferably in the range of 3 to 12% by weight, more preferably in the range of 4 to 12% by weight. The larger the amount, the stronger the breaking strength of the molded body, but as the amount increases, the number of carbon elements and hydrogen elements in the composition increases, and a small amount of CO gas, which is an incomplete combustion product of carbon elements, Is undesirably increased because the concentration of the gas increases and the quality of the generated gas deteriorates. Particularly, when the amount exceeds 12% by weight, the relative proportion of the oxidizing agent needs to be increased, and the relative proportion of the gas generating compound decreases,
It is difficult to establish a practical gas generator system.

Further, when a sodium salt of carboxymethylcellulose is used as a binder, as a secondary effect, a micro-mixed state on the molecular order of sodium nitrate generated by a metal exchange reaction with a nitrate during the production of a molded body using water. The effect of improving the flammability is to shift the decomposition temperature of nitrate, which is an oxidizing agent, particularly strontium nitrate having a high decomposition temperature, to a lower temperature side.

As mentioned above, the preferred gas generant compositions used in the practice of the present invention include: (a) about 25-56%, preferably 30-40%, by weight nitroguanidine; (C) about 1 to 20% by weight, preferably 3 to 10% by weight of the slag forming agent (d) about 3 to 12% by weight, preferably 4 to 65% by weight A gas generant composition comprising 12% by weight of a binder, particularly preferred compositions include: (a) about 30-40% by weight nitroguanidine; (b) about 40-65% by weight strontium nitrate; A gas generant composition comprising 3 to 10% by weight of acid clay or silica and (d) about 4 to 12% by weight of a sodium salt of carboxymethylcellulose.

Preferred examples of the molded article of the gas generating composition of the present invention include: (a) about 25 to 56% by weight of nitroguanidine; (b) about 40 to 65% by weight of an oxidizing agent; A composition comprising 20% by weight of a slag forming agent (d) and about 3 to 12% by weight of a binder is formed into a single-hole cylindrical shape.

Next, a gas generator system for an air bag according to the present invention will be described. The gas generator system of the present invention uses the molded body obtained as described above, and sets a desired tank maximum pressure to P (kPa) in a tank combustion test using the gas generator, and sets the tank maximum pressure P from the start of tank pressure rise. (kPa) 0.25 × T
The tank pressure after millisecond is 0.25 × P (kPa) or less, preferably 0.20 × P (kPa) or less, and the tank pressure after 0.80 × T millisecond is preferably 0.70 × P (kPa) or more. .

The gas generator according to the present invention comprises: a housing having a plurality of gas discharge ports; an igniter disposed in the housing; and a gas generator ignited by the igniter to generate combustion gas. And a combustion chamber containing the gas generating means. Preferably, it also has a filter means for cooling the combustion gas and collecting combustion residues, more preferably, the filter means, the outer periphery of the filter means is opposed to the inner surface of the outer peripheral wall of the housing,
And it is installed so that a gap may be formed between them.

In the gas generator system according to the present invention, the tank maximum pressure P (kPa) and the time T milliseconds from the start of the rise of the tank pressure to the arrival of the tank maximum pressure P (kPa) are the tank maximum pressure P ( D (driver) in which the pressure T is 110 to 220 (kPa) and the time T from the start of the tank pressure rise to the maximum tank pressure P (kPa) is, for example, 30 to 65 milliseconds.
Although the description has been focused on the seat gas generator system, the present technology is not limited to the D seat system, for example, when the maximum pressure P (kPa) is 350 to 500 (kPa) and the tank pressure is The present invention can also be applied to a gas generator system for a P (passenger) seat in which the time T from the start of the rise to the arrival of the tank maximum pressure P (kPa) is, for example, 50 to 70 milliseconds.

FIG. 5 is a longitudinal sectional view showing an embodiment of a gas generator for a D-seat airbag using the molded article of the gas generating composition for an airbag of the present invention.

Referring to FIG. 5, a gas generator comprises a housing 3 comprising a diffuser shell 1 and a closure shell 2.
The interior is defined by an inner cylinder member 16 as two chambers, an ignition means housing chamber 23 and a gas generating agent combustion chamber 28. The igniter 4 and the transfer charge 5 are accommodated in the igniting means accommodating chamber 23 as igniting means for igniting and burning the gas generating agent by being actuated by an impact. A gas generating agent composition molded body 6 of the present invention that generates burned gas is provided, and a substantially disk-shaped under plate 24 that supports the gas generating agent 6 and prevents its movement.
A plurality of gas outlets 11 are arranged at equal intervals in the circumferential direction on the peripheral wall portion 10 of the diffuser shell 1, and the gas outlets 11 are closed by a seal tape 52. The inner shell member 16 of the closure shell 2 is fitted in the central hole 15. The diffuser shell 1 and the closure shell 2 are formed by overlapping the respective flange portions 19 and 20 near a position on the center cross section in the axial direction of the housing 3 and joining the two by laser welding 21 to form the housing 3. .

A caulking portion 27 is formed at the end of the inner cylinder member 16 on the side that houses the igniter 4, and the igniter 4 is fixed by the caulking portion 27. Further, the peripheral wall of the inner cylindrical member 16 has a plurality of through holes 54 arranged at equal intervals to the combustion chamber 28, and the through holes 54 are closed by a seal tape 52 '. Further, a coolant / filter 7 disposed in the housing 1 for purifying and cooling the gas generated by the ignition / combustion of the gas generating agent 6 is disposed so as to surround the gas generating agent 6. An annular chamber or gas generant combustion chamber 28 is defined around 16. The coolant filter 7 is formed by laminating stainless steel flat knit wire meshes in the radial direction and compressing them in the radial and axial directions. Further, outside the coolant filter 7, an outer layer 29 functioning as a suppressing means for suppressing the swelling of the coolant filter is formed. A gap 9 is formed between the outer peripheral wall 8 of the housing 3 and the coolant / filter 7, and the gap 9 functions as a gas flow path.
A short path preventing means 32 for preventing a short path of gas between the housing and the coolant filter is provided on the inner periphery of the coolant filter 7.

The coolant / filter has an inner periphery that protects the filter 7 from flames caused by combustion of the gas generating agent.
It is also possible to provide a perforated basket having a substantially porous cylindrical shape for preventing direct contact between the gas generating agent 6 and the filter 7. Inner cylinder member in the above housing
Inside the gas generating agent combustion chamber 28 defined outside the gas generating agent 16, in addition to the gas generating agent 6, a substantially disk-shaped under plate 24 for supporting the gas generating agent 6 and preventing its movement is disposed. ing. The under plate 24 has a circular portion 25 in contact with the gas generating agent 6 and a central hole 26 into which the outer peripheral wall of the inner cylindrical member 16 is fitted.
The movement of the gas generating agent 6 supported by the cushion 25 'on the circular portion 25 is prevented, and the gas generating agent 6 is broken by vibration, so that there is no possibility that the surface area changes. The outer layer 29, the gap 9, and the perforated basket are provided as needed and may be omitted.

In FIG. 5, reference numeral 17 denotes a cylindrical collar member having a groove 18, and reference numeral 22 denotes an O-ring housed in the groove 18.

[0054]

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 Water was added to 31 parts of nitroguanidine (hereinafter, parts are parts by weight) in an amount corresponding to 15 parts with respect to the total amount of the composition, followed by mixing and kneading. Separately, 54 parts of strontium nitrate, 5 parts of acid clay and 10 parts of sodium salt of carboxymethylcellulose were mixed in a dry system, added to the wet mixed powder, and kneaded.
Next, the kneaded mixture was extruded through a mold having an outer diameter of 3.2 mmφ and an inner diameter of 0.80 mmφ under a pressure of 80 kg / cm ² to form a single-hole cylindrical string. Further, the string was cut into a length of 4.0 mm by a cutting machine, and the moisture was sufficiently dried to obtain a molded article of a gas generating agent.

Using 37 g of the obtained gas generating agent molded body,
A 60 liter tank test at room temperature was performed. Table 1 shows the results. FIG. 1 shows a pressure-time curve obtained in the tank test.

As is clear from the above test results and FIG. 1, the initial tank pressure rise curve becomes gentle, and the maximum pressure reaching time is within the desired time within the desired pressure-time curve. I understand.

The inside of the tank was very clean, and the concentrations of trace amounts of gases such as CO and NOx were within the requirements of the automobile manufacturer.

Examples 2-3 A molded article of a gas generating agent was obtained in the same manner as in Example 1 except that the length was changed as shown in Table 1 by using a cutting machine. The same evaluation as in Example 1 was performed on the obtained gas generating agent molded body. Table 1 shows the results.

Comparative Example 1 A molded article of a gas generating agent was obtained in the same manner as in Example 1 except that the length was cut to 2.0 mm by a cutting machine. The same evaluation as in Example 1 was performed on the obtained gas generating agent molded body. Table 1 shows the results. FIG. 2 shows a pressure-time curve obtained in the tank test.

As apparent from the above test results and FIG. 2, the initial tank pressure rise curve exceeds the desired pressure value,
It can be seen that the initial pressure rise curve is steeper than in Example 1 and the harmfulness to the occupant is high.

[0062]

[Table 1]

[Brief description of the drawings]

FIG. 1 is a pressure-time curve obtained in a tank test of Example 1.

FIG. 2 is a pressure-time curve obtained in a tank test of Comparative Example 1.

FIG. 3 is a layout diagram of holes of a seven-hole drug gas generating agent.

FIG. 4 is a pressure-time curve obtained in a tank test using a seven-hole drug gas generating agent.

FIG. 5 is a longitudinal sectional view showing an example of a gas generator for an airbag using the molded article of the gas generating composition of the present invention.

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-6-107109 (JP, A) JP-A-8-40178 (JP, A) JP-A-8-231291 (JP, A) JP-A-8-108 151288 (JP, A) JP-A-10-87390 (JP, A) JP-A-10-182275 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C06D 5/00 C06D 25 / 34 CAPLUS (STN) WPIDS (STN)

Claims (13)

(57) [Claims] 1. A molded article of a gas generant composition for an airbag, comprising a non-azide gas generant composition, having a perforated shape, and having a length of one perforated molded article. L (m
m), when the inner diameter of the hole of the molded body is d (mm), the value of d is
0.2 to 1.5 (mm), and the value of L / d is 3.0 or more. In a tank combustion test using a gas generator using the molded body, the tank maximum pressure is set to P (kPa), and the tank pressure starts to rise. The time required to reach the tank maximum pressure P (kPa) is T
(Milliseconds), a gas generator composition for an airbag, wherein the tank pressure after 0.25 × T (milliseconds) is adjusted to be 0.25 × P (kPa) or less. 2. The molded body according to claim 1, wherein the length L of the molded body is 1.5 to 30 (mm) and the inner diameter d of the hole is 0.4 to 1.0 (mm). 3. The method according to claim 1, wherein the value of L / d is 3.0 to 10.0.
Or a molded article according to 2. 4. The molding according to claim 1, wherein in the tank combustion test, the tank pressure after 0.25 × T (millisecond) is adjusted to be 0.20 × P (kPa) or less. body. 5. The tank according to claim 1, wherein in the tank combustion test, the tank pressure after 0.80 × T (millisecond) is adjusted to be 0.70 × P (kPa) or more. Molded body. 6. The molded article according to claim 1, wherein a tank maximum pressure P (kPa) is 110 to 220 (kPa) in a tank combustion test. 7. The tank combustion test according to claim 1, wherein the time T from the start of the rise of the tank pressure to the arrival of the tank maximum pressure P (kPa) is 30 to 65 (milliseconds).
A molded article according to the item. 8. The molded article according to claim 5, wherein the non-azide gas generating composition comprises a nitrogen-containing compound, an oxidizing agent, a slag forming agent, and a binder. 9. The molded article according to claim 8, wherein the nitrogen-containing compound is at least one member selected from the group consisting of a tetrazole derivative and a guanidine derivative. 10. The non-azide gas generant composition comprises nitroguanidine or 5-aminotetrazole, strontium nitrate, silica or acid clay, and sodium carboxymethylcellulose, and has a monoporous form. Item 10. The molded article according to any one of Items 5 to 9. 11. The non-azide gas generant composition comprises: (a) about 25-56% by weight nitroguanidine; (b) about 40-65% by weight oxidizing agent; (c) about 1-20% by weight. The molded article according to any one of claims 5 to 10, comprising a slag forming agent, and (d) about 3 to 12% by weight of a binder. 12. The non-azide gas generant composition comprises: (a) about 30-40% by weight nitroguanidine; (b) about 40-65% by weight strontium nitrate; (c) about 3-10% by weight. 12. A molded article according to claim 11, comprising: acid clay or silica, and (d) about 4 to 12% by weight of a sodium salt of carboxymethylcellulose. 13. A housing having a plurality of gas outlets, ignition means provided in the housing, gas generation means ignited by the ignition means to generate combustion gas, and said gas generation means. A gas generator having a combustion chamber for accommodating therein, wherein the gas generating means is a gas generator.
3. A gas generator for an airbag, which is the molded product of the gas generating agent for an airbag according to any one of the above items 2.