JP2002012492A - Gas generator composition for pretensioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas generator composition for pretensioner excellent in ignitability at the initial stage of combustion without generating non- combustibles and also substantially carbon monoxide and hydrogen chloride, and having good moldability. SOLUTION: This gas generator composition for pretensioner includes, as essential components, (A) ammonium perchlorate, (B) a chlorine remover for removing a chlorine-containing derivative generated from ammonium perchlorate, (C) nitrocellulose having 11.7-13.4% nitrogen content and (D) a stabilizer for improving the composition stability with the lapse of time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a gas generating composition for a pretensioner for winding a seat belt.

[0002]

2. Description of the Related Art Conventionally, a vehicle such as an automobile is equipped with a seat belt to protect an occupant from an impact at the time of a collision. Furthermore, in recent years, a pretensioner for retracting a seatbelt is additionally provided to fix an occupant to a seat back before moving forward. Such a pretensioner uses the combustion gas of explosive as power because it is necessary to instantaneously retract the seat belt.

In the operation method, a sensor detects an impact when a vehicle collides at a high speed, and instantaneously ignites an igniter by electric or mechanical means, and burns the gas generating agent by the flame. Due to the high pressure of the generated combustion gas, the piston in the cylinder is instantaneously moved, the method of retracting the seat belt connected to one end of this piston and the belt retracting gear are instantaneously rotated and connected to this gear. The method of retracting the seat belt is adopted.

Conventionally, a propellant containing nitrocellulose as a main component has been used as this gas generating agent. However, since this propellant contains a large amount of carbon monoxide in the generated gas after combustion, a gas generating agent that does not generate carbon monoxide has recently been demanded. At the same time, it is demanded that the ignitability be good and that the combustion be completed in 2 to 15 ms and that no solid residue be generated due to the interruption of the combustion.

[0005] In recent years, in order to meet the above demand, research has been conducted on a gas generating agent containing a binder of an oxidizing agent such as potassium nitrate and a nitrocellulose as a main component. Further, research has been conducted on a gas generating agent mainly composed of an oxidizing agent consisting of ammonium perchlorate and a chlorine scavenger for converting a chlorine-containing derivative generated from ammonium perchlorate into a neutral substance such as NaCl. I have. For example, JP-A-2000-119
No. 088 discloses that at least two groups are selected from (1) a group consisting of nitrocellulose, cellulose acetate nitrate and cellulose nitrate carboxymethyl ether, (2) a nitrogen-containing compound, and (3) an oxide. Disclosed are gas generating compositions for pretensioners each comprising at least one compound.
Japanese Patent Application Laid-Open No. 2-293389 discloses a gas generating agent for a seat belt winding power generating device comprising a perchlorate of ammonia, a nitrate of an alkali metal, and cellulose acetate as a binder. Patent No. 267
No. 0254 discloses a gas generating agent comprising ammonium perchlorate, sodium nitrate and a thermosetting silicone binder as a binder. Further, WO 98/47836 discloses a gas generating agent comprising ammonium perchlorate and a chlorine scavenger and an organic fuel.

[0006]

However, the gas generating composition described in Japanese Patent Application Laid-Open No. 2000-119088 is intended to reduce the amount of carbon monoxide generated, but has recently been required. Does not meet the criteria that virtually no carbon monoxide is generated. JP-A-2
The gas generating agents described in Japanese Patent No. 293389 and Japanese Patent No. 2670254 have poor ignitability at the initial stage of combustion and a low combustion speed, so that the time required for winding the seat belt is long and does not satisfy the required value. In addition, unburned matter generated by the interruption of combustion may be scattered in the automobile. Furthermore, since the gas generating agent described in WO 98/47836 is designed for an airbag, the combustion completion time of the gas generating agent is long and cannot be used for a pretensioner. .

Here, the difference between the gas generating agent used for the pretensioner for winding the seat belt and the gas generating agent used for the airbag will be described. The gas generating agent used in the pretensioner needs to complete combustion in a very short time and wind up the seat belt. Therefore, the combustion completion time required for the gas generating agent is 2 to 1
5 ms. On the other hand, a gas generating agent for an air bag is required to complete combustion in 25 to 55 ms. When a gas generating agent for an air bag designed to complete combustion in 25 to 55 ms is used for a pretensioner, it takes too long to wind up a seat belt, and it is impossible to reliably protect an occupant.
Therefore, it is impossible to divert the gas generating agent used for the airbag to the pretensioner.

The present invention has been made by paying attention to such problems existing in the prior art. The aim is to provide a gas generating composition for a pretensioner that has excellent ignitability in the initial stage of combustion, does not generate unburned substances, does not substantially generate carbon monoxide and hydrogen chloride, and has good moldability. Is to provide.

[0009]

In order to achieve the above object, the gas generating composition for a pretensioner of the first invention comprises the following components (A) to (D) as essential components. . (A) ammonium perchlorate, (B) a chlorine scavenger for removing chlorine-containing derivatives generated from ammonium perchlorate, (C) nitrocellulose having a nitrogen amount of 11.7 to 13.4%, (D) Stabilizer that improves stability over time.

A second aspect of the present invention is that carbon atoms and hydrogen atoms generated from the gas generating composition for a pretensioner can be reacted with all carbon atoms as carbon dioxide and all hydrogen atoms as water. When the stoichiometric weight of the oxidizing agent consisting of ammonium perchlorate and chlorine scavenger is 1.0, the compounding weight of the oxidizing agent consisting of ammonium perchlorate and chlorine scavenger is 1 The gas generating composition for a pretensioner according to the above invention, which has a pH of from 0.0 to 1.4.

A third aspect of the present invention is that the total content of ammonium perchlorate and chlorine scavenger is 63 to 92% by weight, the content of nitrocellulose is 7 to 35% by weight, and the content of the stabilizer is 0%. 0.5 to 5% by weight of the gas generating composition for a pretensioner according to the above invention.

A fourth aspect of the present invention is that the chlorine scavenger is an alkali metal nitrate or carbonate, and the compounding amount is 1.0 to 1.2 mol per 1.0 mol of ammonium perchlorate. A gas generating composition for a pretensioner according to the above invention.

A fifth aspect of the present invention is the gas generating composition for a pretensioner according to the above invention, further comprising an organic polymer binder.

A sixth aspect of the present invention is that the organic polymer binder is a cellulose polymer other than nitrocellulose, a polyester polymer, a polyurethane polymer, a polyether polymer, a thermoplastic elastomer, and an energetic binder. The gas generating composition for a pretensioner according to the invention, which is at least one kind or two or more kinds selected from the group consisting of agents.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail. Gas generating composition for pretensioner of the present invention (hereinafter simply referred to as gas generating composition)
Is (A) ammonium perchlorate as an oxidizing agent,
(B) a chlorine scavenger for removing a chlorine-containing derivative generated from ammonium perchlorate, (C) nitrocellulose having a specific amount of nitrogen as a gas component, and (D) improving stability over time. And, if necessary, an organic polymer binder, a plasticizer, and a combustion improver as a basic composition.

The ammonium perchlorate needs to be a powder in consideration of mixability and flammability. Further, from the viewpoint of improving the mechanical properties and combustion performance of the molded article of the gas generating agent, the average particle diameter is preferably in the range of 1 to 1000 μm, more preferably 1 to 500 μm, and 1 to 500 μm. Particularly preferred is a range of 200 μm. If the average particle size is less than 1 μm, molding becomes difficult. On the other hand, when the average particle size exceeds 1000 μm,
There is a tendency that the mechanical properties of the molded product are deteriorated and the burning rate is reduced.

Next, the chlorine scavenger will be described. The chlorine scavenger is capable of capturing a chlorine-containing derivative generated during the combustion of ammonium perchlorate, and for example, suppresses the chlorine-containing derivative from being substantially released into an automobile. Here, “substantially does not release chlorine-containing derivatives” means that the measured value obtained by the following test method is 60 p.
pm. First, a gas generating agent molded product
0 g is burned in a 10 cc sealed bomb, then the valve is opened and coalesced with 1 atmosphere of air in an adjacent 60 liter container. After cooling, measure the concentration of hydrogen chloride in the product gas after cooling using a Kitagawa gas detector tube for hydrogen chloride (measurement range: 20 to 1200 ppm (minimum concentration at which discoloration is recognized is 5 ppm)). I do. The chlorine scavenger is not particularly limited as long as it is an alkali metal nitrate, carbonate, oxide and hydroxide. Preferred among these are alkali metal nitrates and carbonates, most preferred are lithium, sodium and potassium nitrates and carbonates.

[0018] The chlorine scavenger must be a powder from the viewpoint of miscibility and flammability. Then, from the viewpoint of improving the mechanical properties and combustion performance of the gas generating agent molded product, the average particle size is preferably in the range of 1 to 1000 μm, more preferably 1 to 500 μm, and 1 to 500 μm. Particularly preferred is a range of 200 μm.
If the average particle size is less than 1 μm, molding is difficult. On the other hand, if the average particle diameter exceeds 1000 μm, it is difficult to mix with the binder, so that the mechanical properties of the molded product are deteriorated and the burning rate tends to be slow.

The amounts of ammonium perchlorate and chlorine scavenger are determined from the viewpoint of preventing carbon monoxide from being produced in the produced gas. That is, carbon atoms and hydrogen atoms generated from the gas generating composition, from ammonium perchlorate and chlorine scavenger, which can chemically change all carbon atoms to carbon dioxide and all hydrogen atoms to water When the stoichiometric weight of the oxidizing agent is 1.0, the weight of the oxidizing agent comprising the ammonium perchlorate and the chlorine scavenger is preferably in the range of 1.0 to 1.4. .0
A range of 1.2 is more preferred. The range of 1.0 to 1.1 is most preferred. If the amount is less than 1.0, carbon monoxide tends to be produced in the produced gas. On the other hand, when the ratio exceeds 1.4, the amount of gas generated tends to decrease, and the moldability tends to deteriorate.

The total amount of the ammonium perchlorate and the chlorine scavenger is determined from the viewpoint of improving the amount of gas generated by the gas generating agent and improving the combustion performance, by using ammonium perchlorate, the chlorine scavenger, nitrocellulose and the stabilizer. 6 for the total amount
The range is preferably from 3 to 92% by weight, more preferably from 70 to 85% by weight. If the amount is less than 63% by weight, carbon monoxide tends to be produced in the produced gas. On the other hand, if it exceeds 92% by weight, the burning rate tends to be low, and the combustion at a low pressure tends to be unable to be maintained.

In the present invention, "substantially no carbon monoxide is formed" means that the measured value obtained by the following test method is 5 p.
pm. First, a gas generating agent molded product
0 g is burned in a 10 cc sealed bomb, then the valve is opened and coalesced with 1 atmosphere of air in an adjacent 60 liter container. After allowing to cool, the measurement is performed using a Kitagawa gas detector tube for carbon monoxide (measurement range: 20 to 1000 ppm (minimum concentration at which discoloration is observed is 5 ppm)). If there is no discoloration, it is less than 5 ppm.

In the case where an alkali metal nitrate or carbonate is used as the chlorine scavenger, the amount of ammonium perchlorate is from the viewpoint of reducing the amount of chlorine generated in the generated gas and improving the amount of generated gas. 1.00 to 1.20 mol is preferable with respect to 1.00 mol, and
1.15 mol is more preferred, and 1.05 to 1.10 mol is particularly preferred. If the amount is less than 1.00 mol, the chlorine-containing derivative generated from ammonium perchlorate cannot be completely captured and tends to be released into the automobile. Conversely, if it exceeds 1.20 mol, the amount of gas generated tends to decrease.

Next, nitrocellulose will be described.
Nitrocellulose is mainly used as a gas component, but at the same time is also a binder for granulating (graining) powder components such as ammonium perchlorate.
Nitrocellulose is a nitrate ester of cellulose, and its nitrogen amount is usually 11.7 to 13.4%. Preferably 12.2 to 13.4%, more preferably 12.9%.
13.2%. If this nitrogen amount is less than 11.7%,
Since the flammability of the gas generating composition is reduced and the powder component is too soluble in the organic solvent to enclose the powder component, molding becomes difficult. Conversely, if the nitrogen content exceeds 13.4%, the heat resistance of the gas generating composition tends to decrease, and nitrocellulose tends to be insoluble in the organic solvent, making molding impossible. The amount of nitrocellulose, the combustion performance of the gas generating agent, the amount of generated gas, moldability, and from the viewpoint of preventing carbon monoxide from being generated in the generated gas, ammonium perchlorate, chlorine scavenger, The range is preferably from 7 to 35% by weight, more preferably from 15 to 30% by weight, based on the total amount of the nitrocellulose and the stabilizer. If the compounding amount is less than 7% by weight, the burning rate becomes slow, the burning at a low pressure cannot be maintained, and the moldability tends to be reduced. If it exceeds 35% by weight, carbon monoxide tends to be produced in the produced gas.

Next, the stabilizer will be described. Any stabilizer that can improve the temporal stability of the molded article of the gas generating agent can be used. For example, diphenylurea derivatives such as diphenylurea, methyldiphenylurea, ethyldiphenylurea, diethyldiphenylurea, dimethyldiphenylurea, and methylethyldiphenylurea; diphenylamine derivatives such as diphenylamine and 2-nitrodiphenylamine; ethylphenylurethane; methylphenylurethane; Phenyl urethane derivatives, diphenyl urethane derivatives such as diphenyl urethane, resorcinol and the like. In particular, diphenylamine and diethyldiphenylurea are preferable in that they are excellent in the stability over time of the gas generating agent molded article and the ignitability at the beginning of combustion. The amount of the stabilizer is selected from the viewpoints of the stability over time of the gas generating agent and the fact that carbon monoxide is not substantially generated in the produced gas, ammonium perchlorate, chlorine scavenger, nitrocellulose and the stabilizer. For the total amount of
The range is preferably 0.5 to 5.0% by weight, and 1.0 to 4.0% by weight.
The range of 5% by weight is more preferable, and the range of 1.0 to 4.0% by weight is more preferable. If the amount of the stabilizer is less than 0.5% by weight, the effect of improving the stability tends to decrease. If the content exceeds 5.0% by weight, the effect as a stabilizer increases, but the mixing ratio of other components decreases, so that the combustibility deteriorates and carbon monoxide tends to be generated in the produced gas. .

Next, the organic polymer binder will be described. The organic polymer-based binder is blended together with nitrocellulose and is mainly used as a binder for granulating (graining) powder components such as ammonium perchlorate. Such organic polymer binders include, for example, cellulose polymers other than nitrocellulose, polyester polymers, polyurethane polymers, polyether polymers,
Thermoplastic elastomers and glycidyl azide polymers,
Energetic compound binders such as 3,3-bis (azidomethyl) oxetane, 3-azidomethyl-3-methyloxetane, and 3-nitratemethyl-3-methyloxetane. At least one selected from these is used as needed.

The amount of the organic polymer-based binder is controlled to suppress the generation of unburned substances caused by interruption of combustion,
From the viewpoints of ignitability and burning rate, it is preferably 90% by weight or less, more preferably 60% by weight or less, and particularly preferably 40% by weight or less based on the total amount of the organic polymer-based binder and nitrocellulose. If the compounding amount of the organic polymer-based binder exceeds 90% by weight, the ignitability and the burning rate tend to decrease, and the unburned matter generated by interrupting the combustion tends to increase.

It is preferable to add a plasticizer to the gas generating composition in order to impart plasticity and improve moldability. As such a plasticizer, any plasticizer having good compatibility with the binder can be used. For example, dibutyl phthalate, dimethyl phthalate, phthalate diester plasticizers such as diethyl phthalate, phosphate esters, triacetin, fatty acid ester plasticizers such as acetyltriethyl nitrate, trimethylol ethane trinitrate, diethylene glycol dinitrate, triethylene glycol Examples include nitro plasticizers such as dinitrate, nitroglycerin, bis-2,2-dinitropropyl acetal / formal, and glycidyl azide plasticizer. The amount of the plasticizer to be added is preferably 5% by weight or less in the gas generating composition from the viewpoint that carbon monoxide is not substantially generated in the generated gas, and 0.5 to 4%.
% By weight, more preferably from 0.5 to 2% by weight. If the added amount of the plasticizer exceeds 5% by weight, the effect as a plasticizer is increased, but the mixing ratio of other components is reduced, so that the flammability is deteriorated and carbon monoxide tends to be generated in the generated gas. It is in.

Next, a combustion enhancer for further improving the combustion speed of the gas generating agent will be described. Examples of the combustion improver include a high energy substance and a combustion catalyst.
Examples of the high-energy substance include RDX (trimethylenetrinitroamine), HMX (tetramethylenetetranitroamine), PETN (pentaerythritol tetranitrate), TAGN (triaminoguanidine nitrate), and HN (hydrazine nitrate). Is mentioned.

Examples of the combustion catalyst include metal oxides such as iron oxide, copper oxide, chromium oxide, cobalt oxide, and aluminum oxide; ferrocene derivatives such as ferrocene, n-butylferrocene and catocene; metal powders such as magnesium; Metal fluorides such as lithium and boron hydride are exemplified.

The average particle size of the combustion improver is determined from the viewpoint of mechanical properties and combustion performance of the molded article of the gas generating agent.
It is preferably in the range of 1 to 500 μm,
0 μm, more preferably 1 to 30 μm.
The range of m is particularly preferred. If the average particle diameter is less than 1 μm, molding is difficult. On the other hand, when the average particle size exceeds 500 μm, the mixture with the binder is poor, so that the mechanical properties of the molded product are deteriorated, and the effect of improving the burning speed tends not to be exhibited.

The compounding amount of the combustion improver is preferably 15% in the gas generating composition from the viewpoint of improving handleability and combustion performance and substantially preventing carbon monoxide from being generated in the produced gas. %, Preferably 1 to 10% by weight, more preferably 1 to 5% by weight. If the compounding amount exceeds 15% by weight, the effect as a combustion improver increases, but the mixing ratio of other components decreases, and carbon monoxide tends to be generated in the product gas.

Next, the manufacturing method will be described. First, a predetermined amount of ammonium perchlorate, a chlorine scavenger, nitrocellulose, a stabilizer, and if necessary, an organic polymer binder, a combustion enhancer, and a plasticizer are weighed. After the measurement, all the raw materials are put into a kneading machine, and an appropriate amount of an organic solvent is added into the kneading machine and mixed uniformly. Next, the mixture is charged into an extruder, a predetermined pressure is applied, and the mixture is extruded while passing through a die, thereby obtaining a gas generating agent molded product having a predetermined shape and size.

As the organic solvent used in the extrusion molding method, any organic solvent which completely dissolves the binder can be used.
For example, organic solvents such as acetone, ethyl alcohol, and ethyl acetate can be used. These mixed solutions can also be used. For example, in a mixed solution of acetone and ethyl alcohol, the mixing ratio of acetone / ethyl alcohol = 9
The range of 0/10 to 20/80% by weight is preferred. Considering the moldability of the gas generating composition, the range of acetone / ethyl alcohol = 80/20 to 40/60% by weight is more preferable. This is because it is difficult to produce nitrocellulose and the organic polymer binder completely by using only ethyl alcohol because the evaporation rate is high, and it is difficult to completely dissolve nitrocellulose and the organic polymer binder only by using acetone.

Next, a description will be given with reference to a conceptual diagram. The produced gas generating agent molded product is shown in FIG. The shape is a columnar body 2 as shown in (a), a cylindrical body 2 having a through hole 3 extending in the axial direction as shown in (b), and a cylinder having seven through holes 3 as shown in (c). Body 2, 19 as shown in (d)
The cylindrical body 2 has a plurality of through holes 3. Furthermore, (e)
A modified columnar body 4 having seven through holes 3 as shown in FIG.
(F) A deformed column 4 having 19 through holes 3 as shown in (f), a hexagonal column 5 having 7 through holes 3 as shown in (g), and 19 hexagonal columns 5 as shown in (h) A hexagonal prism 5 having a through hole 3 is exemplified. In the gas generating agent molded products 1 shown in (c) to (h), the shapes connecting the centers of the through holes 3 on the outer periphery are all regular hexagons, and the shapes connecting the centers of the three adjacent through holes 3 are all positive. It forms a triangle. Therefore, the distance between the three through holes is equal.

The gas generant composition of the present invention is required to complete combustion in an extremely short time of 2 to 15 ms when an automobile collides. Therefore, the shape is usually 0.5
~ 4mm, inner hole diameter 0.1 ~ 3.5mm, drug length 0.5
A cylindrical body 2 having a through hole 3 as shown in FIG. 3B of about 4 to 4 mm, or an outer diameter of about 0.5 to 4 mm and an inner hole diameter of about 0 to 4 mm.
Those shown in (c) of about 1 to 1 mm and about 0.5 to 4 mm in drug length are preferred. If the combustion completion time is less than 2 ms, the retraction of the seat belt becomes too fast, damaging the occupant's shoulders and chest. Conversely, if the combustion is completed for more than 15 ms, the retraction of the seat belt becomes slow, so the pretensioner is not used. This is because there is a tendency that the performance cannot be sufficiently exhibited.

In consideration of the moldability, the gas generation rate, and the charging into the gas generator, the dimensions of the gas generating agent molded product are preferably 0.5 to 2.0 mm in outer diameter and 0.5 mm in drug length.
２．０2.0 mm. If the thickness from the surface of the molded product to the inner hole is 0.1 mm or less or the drug length is less than 0.5 mm, molding tends to be difficult. When the outer diameter or the drug length exceeds 2 mm, the gas generator tends to be unable to be charged with a required amount of the gas generating agent. Furthermore, when the thickness from the surface of the molded product to the inner hole exceeds 1 mm, the gas generation rate is low,
There is a tendency that the performance as a gas generating agent cannot be sufficiently exhibited.

If a large amount of an organic solvent such as acetone, ethyl alcohol, and ethyl acetate remains in the gas generating composition, the combustion performance deteriorates. Therefore, it is preferable to remove the organic solvent as much as possible. The organic solvent content at the end of drying is usually 0.8% by weight or less, and the moisture content is preferably 1.5% by weight or less. % Is more preferable. The organic solvent content at the end of the drying is particularly preferably 0.3% by weight or less and the water content 0.7% by weight or less. When the organic solvent content exceeds 0.8% by weight or the water content exceeds 1.5% by weight, the gas generation rate, mechanical properties and ignitability of the molded article of the gas generating agent tend to decrease.

[0038]

The present invention will be described more specifically below with reference to examples. Example 1 38.8% by weight of ammonium perchlorate having an average particle diameter of 15 μm, 29.5% by weight of sodium nitrate having an average particle diameter of 15 μm, 25.7% by weight of nitrocellulose having a nitrogen amount of 13.15%, and diphenylamine 3.5 20% by weight of acetone and 10% by weight of ethyl alcohol based on a gas generating agent mixture adjusted to have a ratio of 1.0% by weight of dibutyl phthalate and 1.0% by weight of iron oxide as a combustion improver.
And mixed uniformly with a Werner mixer. The Werner pulverizer is a device for stirring and mixing with a stirring blade supported on a rotating shaft extending in a lateral direction.

Next, the mixture was charged into an extruder. A 2.0 mm die and 0.29
mm pin is attached. The gas generant mixture is extruded through this die by applying pressure, and is formed into a seven-hole shape having seven through holes. This molded product was cut into a length of 1.8 mm and dried to obtain a columnar gas generating agent molded product. At that time, the productivity was also evaluated. The evaluation criteria for manufacturability are as follows. ◎
Has very good productivity, that is, there is no problem in the physical strength of the molded product, and further, there is no crack or chip in the molded product. O indicates that there is no problem regarding the physical strength of the molded product and cracking or chipping of the molded product, but the productivity is slightly poor and the production is difficult. △ means that the physical strength of the molded product is weak,
It is poor in manufacturability in which molded articles often have cracks and chips. Further, x indicates that molding is impossible. 1.0 g of the molded product of the gas generating agent was burned by a 10 cc bomb device, and the concentration of carbon monoxide, the concentration of hydrogen chloride and the completion time of burning in the produced gas were determined. The results are shown in Table 1.

[0040]

[Table 1]

First, a 10 cc bomb test apparatus will be described. FIG.
As shown in the figure, a combustion chamber 7 having a volume of 10 cc is provided in the bomb body 6, and a gas generator 8 loaded with a gas generating agent molded product is mounted in contact with the combustion chamber 7. An electrode 11 is attached to the outside of the gas generator 8 (the side opposite to the combustion chamber 7). By operating the igniter 10, the igniter in the gas generator 8 is ignited via the connection wiring 9, the electrode 11, etc.
To ignite and burn. When the inside of the gas generator reaches a predetermined pressure, the sealing plate in front of the gas generator is broken, and gas is blown out to the combustion chamber.

A gas transfer valve 12 is attached to the other end face of the bomb body 6 on the side opposite to the igniter, and communicates with a 60-liter container via a connecting pipe 13. In addition, 1 atmosphere of air is contained in this container. The gas transfer valve 12 is opened, the gas in the combustion chamber is sent to the 60-liter container 14, and the gas in the 60-liter container is subjected to gas analysis.

The pressure transducer 15 attached to the side surface of the bomb body 6 communicates with the combustion chamber 7 via a communication pipe 16. The pressure converter 15 can determine the relationship between the combustion time and the combustion pressure when the sample is burned.

After the gas generator 8 loaded with the gas generating agent molded article 1 is attached, the ignition device 10 ignites the gas generating agent molded article 1 in the gas generator 8. After burning the gas generating agent molded product 1, the gas transfer valve 12 is opened, and the combustion gas is sent into the 60 liter container, and after 5 minutes, the generated gas in the 60 liter container is collected. The concentrations of carbon monoxide and hydrogen chloride in the sampled product gas were determined using a Kitagawa gas detector tube. The measurement range of carbon monoxide is 20 to 1000 p.
pm (minimum density of 5 ppm at which discoloration is observed) and 0.1 to 2.0% (minimum density of 0.02 at which discoloration is observed)
%). Hydrogen chloride has a measurement range of 2
0 to 1200 ppm (minimum concentration 5pp at which discoloration is observed)
m) was used. Further, the combustion completion time (time from the energization to the completion of combustion) when the gas generating agent molded article 1 burns was measured by an oscilloscope via the pressure transducer 15.

Examples 2 to 7 With the compositions shown in Tables 1 and 2, gas generating compositions were produced in the same manner as in Example 1, and the characteristics of each were evaluated in the same manner as in Example 1. The results are shown in Tables 1 and 2.

[0046]

[Table 2]

Comparative Examples 1 to 6 With the compositions shown in Table 3, gas generating compositions were produced in the same manner as in Example 1, and the characteristics of each were evaluated in the same manner as in Example 1. Table 3 shows the results.

[0048]

[Table 3]

The test results in Tables 1 to 3 are as follows.
In Examples 1 to 7, no discoloration was observed in the detector tube. Therefore, carbon monoxide is substantially 0p in the product gas.
pm, and there were no problems with the combustion completion time and productivity. Further, in Examples 1 to 7 in which the mixing amount of ammonium perchlorate and sodium nitrate as a chlorine scavenger is 1.00 to 1.20 mol per 1 mol of ammonium perchlorate, Has a hydrogen chloride concentration of 60
ppm, and there were no problems with the combustion completion time and productivity.

In Example 6 in which cellulose acetate was blended at 70% by weight based on the total weight of cellulose acetate and nitrocellulose, the combustion completion time was slightly slower than that in the example using only nitrocellulose. Value 2
15 ms was satisfactory.

As shown in Comparative Example 1, with the propellant containing nitrocellulose as the main component, there was no problem with the time required for completing the combustion and the productivity, but a very large amount of carbon monoxide was generated in the produced gas. Therefore, it was found that ammonium perchlorate must be used in order to use a gas generating agent that does not generate carbon monoxide. Further, as shown in Comparative Example 2, carbon atoms and hydrogen atoms generated from the gas generating composition were converted into perchloric acid capable of reacting all carbon atoms with carbon dioxide and all hydrogen atoms with water. When the stoichiometric weight of the oxidizing agent consisting of ammonium and chlorine scavenger is 1.0, the weight of the oxidizing agent consisting of ammonium perchlorate and chlorine scavenger is less than 1.0. The gas generating agent generated carbon monoxide. Therefore, in order to use a gas generating agent that does not generate carbon monoxide, it is necessary to use the oxidizing agent in an amount of 1.0 or more.

As shown in Comparative Example 3, in the molded article using no chlorine scavenger, there is no problem in carbon monoxide, combustion completion time and productivity in the produced gas, but hydrogen chloride is contained in the produced gas. Very many occurrences. Therefore, it was found that it was necessary to use a chlorine scavenger in order to use a gas generating agent that does not generate hydrogen chloride.

Further, as shown in Comparative Example 4, in a molded product obtained by graining only with cellulose acetate which is an organic polymer-based binder without using nitrocellulose, there is no problem with the generated gas component, Therefore, it is not suitable for a gas generating agent for a pretensioner, because of poor combustion performance and a long combustion completion time. Therefore, it was found that it was necessary to use nitrocellulose in order to satisfy the required performance.

As shown in Comparative Examples 5 and 6, when nitrocellulose having a nitrogen content outside the range of 11.7% to 13.4% was used, there was a problem in solubility in organic solvents. A gas generating agent molded product could not be manufactured. Therefore,
In order to produce a gas generant molded article, the amount of nitrogen must be 11.
It has been found necessary to use nitrocellulose in the range of 7% to 13.4%. In addition, as a result of an actual machine test using a seat belt, about 50% of the charged amount of unburned matter was generated in Comparative Example 4, whereas unburned matter was observed in Examples 1 to 7. Did not.

[0055]

As described in detail above, the present invention has the following excellent effects. According to the first gas generating composition of the present invention, ammonium perchlorate, chlorine scavenger and nitrocellulose react efficiently, so that the ignitability is good and the unburned matter generated by interrupting combustion is reduced. Generation was suppressed, and the stability over time could be further improved by the effect of the stabilizer. According to the second gas generating composition of the present invention, in addition to the effects of the first invention, it is possible to suppress the generation of carbon monoxide and further improve the moldability. According to the third gas generating composition of the present invention, in addition to the effects of the first and second aspects, the burning rate is improved, the combustion at a low pressure can be maintained, and the effective gas generation amount can be increased. it can. According to the fourth gas generating composition of the present invention, in addition to the effects of the first and second inventions, generation of hydrogen chloride can be substantially suppressed. According to the fifth or sixth gas generating composition of the present invention, the stability over time can be further improved.

[Brief description of the drawings]

FIG. 1 (a) is a perspective view showing an example of the shape of a molded article of a gas generating agent of the present invention.

FIG. 2 is a perspective view showing an example of the shape of a molded article of a gas generating agent of the present invention.

FIG. 1 (c) is a perspective view showing an example of the shape of a molded article of a gas generating agent of the present invention.

FIG. 4 is a perspective view showing an example of the shape of a molded article of a gas generating agent of the present invention.

FIG. 1 (e) is a perspective view showing an example of the shape of a molded article of a gas generating agent of the present invention.

FIG. 6 is a perspective view showing an example of the shape of a molded article of a gas generating agent of the present invention.

FIG. 1 (g) is a perspective view showing an example of the shape of a molded article of a gas generating agent of the present invention.

FIG. 1 (h) is a perspective view showing a shape example of a molded article of a gas generating agent of the present invention.

FIG. 9 is a sectional view showing a 10 cc bomb test apparatus for measuring combustion of a molded article of a gas generating agent of the present invention.

[Explanation of symbols]

 1 ... gas generating agent molding. 2 ... Cylinder 3 ... Through hole 4 ... Deformed column 5 ... Hexagonal column 6 ... Bomb body 7 ... Combustion chamber 8 ... Gas generator 9 ... Connection Wiring 10 ... Ignition device 11 ... Electrode 12 ... Gas transfer valve 13 ... Connection tube 14 ... 60 liter container 15 ... Pressure converter 16 ... Communication tube

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) C06B 25/28 C06B 25/28 29/22 29/22 C06D 5/06 C06D 5/06

Claims (6)

[Claims] 1. A gas generating composition for a pretensioner comprising the following components (A) to (D): (A) ammonium perchlorate, (B) a chlorine scavenger for removing chlorine-containing derivatives generated from ammonium perchlorate, (C) nitrocellulose having a nitrogen amount of 11.7 to 13.4%, (D) Stabilizer that improves stability over time. 2. An ammonium perchlorate and a chlorine capable of reacting carbon atoms and hydrogen atoms generated from a gas generating composition for a pretensioner with carbon dioxide and hydrogen atoms with water. When the stoichiometric weight of the oxidizing agent consisting of the scavenger is 1.0, the weight of the oxidizing agent consisting of ammonium perchlorate and the chlorine scavenger is 1.0 to 1.4. The gas generating composition for a pretensioner according to claim 1. 3. The total amount of ammonium perchlorate and chlorine scavenger is 63 to 92% by weight, the content of nitrocellulose is 7 to 35% by weight, and the content of stabilizer is 0.5 to 5% by weight. The gas generating composition for a pretensioner according to claim 1 or 2, which is: 4. The chlorine scavenger is an alkali metal nitrate or carbonate, and the compounding amount thereof is 1.0 to 1.2 mol per 1 mol of ammonium perchlorate. 4. The gas generating composition for a pretensioner according to any one of the above items 3. 5. The gas generating composition for a pretensioner according to claim 1, further comprising an organic polymer binder. 6. The organic polymer binder is selected from the group consisting of cellulose polymers other than nitrocellulose, polyester polymers, polyurethane polymers, polyether polymers, thermoplastic elastomers and energy binders. The gas generating composition for a pretensioner according to claim 5, which is at least one kind or two or more kinds selected.