JP2005219987A - Igniter molding and gas generator therewith - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an igniter molding which initiates combustion of a gas generating agent with a small quantity of it by regulating the combustion speed of the igniter molding for the gas generating agent of low reactivity (low ignition tendency), and a gas generator therewith. <P>SOLUTION: This igniter molding contains a metal powder (a), a nitrogen-containing organic compound (b), and an oxidizing agent (c), and has a calorific value of not smaller than 4,500 J/g, is classified in 1 to 10 mm, and has a bulk density of 0.90-1.20 g/cm<SP>3</SP>. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  TECHNICAL FIELD The present invention relates to a charge transfer molded product aimed at improving the ignitability of a gas generating agent, that is, a charge transfer molded product having a good ignition ability in a small amount, and a gas generator having the same.

  The airbag device is an occupant protection device that has been widely adopted in recent years in order to improve the safety of automobile occupants. The principle is that a sensor generates an electrical signal when a collision is detected, operates a gas generator, deploys an air bag, and works to reduce the impact on the passenger due to the collision. This gas generator must be a highly reliable automobile safety component that is required to operate normally even under severe environmental conditions such as temperature, humidity, and vibration.

  The order in which the gas generator operates is that the ignition device first ignites by a signal from the sensor that sensed the collision, and then, after transferring to the transfer charge, the transfer charge flame and the metal thermal particles contained therein, Ignite the gas generant. Here, the role of the charge transfer agent is to ignite the gas generating agent and start combustion of the gas generating agent without delay. The gas generator that has started combustion generates sufficient gas in a predetermined time, and exhibits the original performance of protecting the occupant by inflating the airbag. Therefore, the characteristic required for the charge transfer agent is to start combustion of the gas generating agent without delay from the operation of the ignition device. Conventionally used explosives are mainly composed of about 15 to 30% by weight (generally about 25% by weight) boron and about 70 to 85% by weight (generally about 75%) of potassium nitrate. The so-called “boron nitrate” is generally used. This explosive is widely used because it has excellent thermal stability, burns instantaneously, generates a large amount of heat, and has a small rate of change in combustion speed due to changes in ambient pressure. In addition, boron nitrate is generally used as a granular drug.

  In recent years, an explosive agent that can be used in an air bag gas generator has been developed as an alternative to boron nitrate. For example, Patent Document 1 discloses a self-igniting transfer composition containing 5-aminotetrazole, boron fine powder, potassium nitrate, molybdenum trioxide, and a binder and having a calorific value of 4500 J / g or more. . Patent Document 2 discloses an igniter rod-like body containing boron powder, potassium nitrate, and a binder.

However, in the auto-ignition enhancer (transfer agent) composition described in Patent Document 1 and the ignition powder rod described in Patent Document 2, the burning rate is in the range of 50 to 350 m / sec and the bulk density thereof. Is not mentioned in the range of 0.90 to 1.20 g / cm ³ . In addition, the igniter rod-like body described in Patent Document 2 does not mention that a nitrogen-containing organic compound is contained.

Japanese Patent Laid-Open No. 2001-80986 Special table 2003-524565

  Conventionally, explosives have been required to have a fast combustion rate so that there is no delay in the ignition of the gas generant. The amount of gas used for changes in the gas generant, especially for gas generators with poor ignitability, is required. By increasing the, we have ensured reliable ignition. In this case, the transfer charge has a large amount of generated heat, which increases the load on the cooling member in the gas generator, increases the number of cooling members used, and increases the total weight of the gas generator. In addition, most of the explosive charge becomes a solid residue after combustion, and when it is used in a large amount, in the worst case, it may become an outflow residue from the gas generator and cause bag damage.

  The present invention provides a charge transfer agent molded body that reliably starts combustion of a gas generant in a small amount by adjusting the combustion rate of the transfer charge with respect to a gas generating agent having poor reactivity (poor ignitability). An object of the present invention is to provide a gas generator.

  As a result of intensive investigations to solve the above problems, the present inventors have adjusted the combustion rate of the charge transfer agent, so that even when a gas generating agent having poor reactivity (poor ignitability) is used, it is good. It was found to show ignitability.

That is, the present invention relates to the following (1) to (8).
(1) Including each of the following components (a), (b), and (c), the calorific value is 4500 J / g or more, classified into 1 to 10 mm, and further the bulk density is 0.90 to 1.20 g. A charge transfer molding that is / cm ³ .
(A) Metal powder (b) Nitrogen-containing organic compound (c) Oxidizing agent (2) The transfer charge molded article according to (1), wherein the burning rate is 50 to 350 m / sec.
(3) The transfer charge molded article according to (1) or (2), wherein the surface area per molded article is 10 to 150 mm ² / piece.
(4) The transfer powder according to any one of (1) to (3), wherein the metal powder is at least one selected from boron, aluminum, magnesium, magnalium, silicon, titanium, titanium hydride and zirconium. Molded body.
(5) The charge transfer molded article according to any one of (1) to (4), wherein the nitrogen-containing organic compound is at least one selected from a tetrazole derivative, a guanidine derivative, a hydrazine derivative, and a metal complex. .
(6) The explosive charge molded article according to any one of (1) to (5), wherein the oxidizing agent is at least one selected from the group consisting of potassium nitrate, sodium nitrate, and strontium nitrate.
(7) 3 to 20% by weight of the tetrazole derivative, 5 to 30% by weight of boron, 50 to 85% by weight of potassium nitrate, and 2 to 15% by weight of a binder for molding (1) to (6) An explosive charge molding according to any one of the above.
(8) A gas generator for an automobile occupant protection device having the explosive charge molding according to any one of (1) to (7).

  Conventional explosives have been characterized in that they are granular and have a high combustion rate in order to ensure the ignitability of the gas generating agent.In the present invention, the explosive is made into a molded body, and the combustion rate is higher than that of conventional explosives. By slowing down, the combustion time can be lengthened, and the combustion of the gas generating agent having poor ignitability can be reliably started without increasing the amount of drug used. In addition, when the explosive charge molding of the present invention was used, good ignitability was exhibited in the ignitability of the gas generant under a low temperature environment required for the automobile occupant protection device gas generator.

The present invention includes (a) metal powder, (b) nitrogen-containing organic compound, and (c) an oxidizing agent, and has a calorific value of 4500 J / g or more, classified into 1 to 10 mm, and further has a bulk density. The present invention relates to an explosive charge molding which is 0.90 to 1.20 g / cm ³ .

  In the explosive charge compact of the present invention, at least one metal powder is used. The metal powder that can be used in the present invention is not particularly limited as long as it can become hot particles, and not only a powder of a single metal but also a powder of an alloy can be employed.

  Specific examples of the metal powder include boron, aluminum, magnesium, magnalium, silicon, titanium, titanium hydride, and zirconium. Boron is particularly preferable because of its low handling risk and low price. As the content (ratio) of the metal powder in the transfer powder molded body increases, the calorific value increases and the number of metal heat particles also increases. The content is preferably 5 to 30% by weight, and more preferably 16 to 25% by weight. When the content is 5% by weight or less, the calorific value is reduced and the metal hot particles are reduced. When the content is 30% by weight or more, the amount of the oxidant used in the charge transfer molding. Decreases and the ignition ability decreases.

  In the explosive charge molding of the present invention, a nitrogen-containing organic compound used as a fuel component of the gas generating agent is used. In the present invention, by adding a nitrogen-containing organic compound to the transfer agent, a flame is generated by combustion, and the ignition performance can be improved both with the metal particles derived from the metal component. As the nitrogen-containing organic compound, for example, a tetrazole derivative, a guanidine derivative, a hydrazine derivative, or a metal complex that can be generally used as a fuel component in a gas generator for an air bag can be used. The content (ratio) in the compact varies depending on the metal powder, the oxidizing agent, the type of additives, the oxygen balance, etc., but is preferably 30 to 70% by weight, more preferably 35 to 60% by weight.

  As the tetrazole derivative, tetrazole, 5-aminotetrazole, bitetrazole, bitetrazole diammonium salt, or the like is preferably used. Among them, among the nitrogen-containing organic compound components, 5-aminotetrazole is extremely easy to handle, including stability and safety, is inexpensive, and is a more preferable substance among nitrogen-containing organic compounds. is there.

  As the guanidine derivative, it is preferable to use one or more selected from the group consisting of nitroguanidine, guanidine nitrate, aminoguanidine nitrate, and mixtures thereof. In particular, guanidine nitrate has a relatively low cost, has a melting point higher than 200 ° C., is extremely thermally stable, and is suitable from the viewpoint of environmental resistance.

  As the hydrazine derivative, carbodihydrazide or the like is preferably used.

  As the metal complex, a transition metal hydrazine complex, ammine complex, or the like is preferably used, and examples of the ammine complex include hexaamminecobalt nitrate.

  The content (ratio) of the nitrogen-containing organic compound in the explosive molding is preferably 3 to 25% by weight, and more preferably 5 to 15% by weight. When the content of the nitrogen-containing organic compound is 25% by weight or more, the heat generation amount of the gas generating agent is decreased and the metal heat particles are reduced, that is, the ignition power is insufficient, and the content is 3% by weight or less. In some cases, the ignition power is reduced due to the lack of gas flow.

  If the 50% particle size of the nitrogen-containing organic compound is too large, the strength in the case of forming an explosive charge product is reduced, and if it is too small, a large cost is required for pulverization. Preferably, it is 10-50 micrometers. In the present specification, 50% particle size means a number-based 50% average particle size.

  An oxidizing agent is used in the explosive charge molding of the present invention. Examples of the oxidizing agent include nitrates, perchlorates, chlorates, metal oxides, metal peroxides, and the like. Among these, nitrates are preferable from the viewpoints of safety, stability, and cost, and specifically, at least one selected from the group consisting of potassium nitrate, sodium nitrate, and strontium nitrate is preferable. In particular, potassium nitrate is preferred because it is not hygroscopic and is easy to handle. The content (ratio) of the oxidizing agent in the explosive charge molded body is preferably 50 to 85% by weight, more preferably 60 to 80% by weight. When the content is 50% by weight or less, the oxygen supply amount is insufficient, resulting in incomplete combustion, and harmful carbon monoxide is generated. If it is 85% by weight or more, harmful nitrogen oxides are generated.

  The explosive charge molded article of the present invention is suitably used for a gas generator used in an automobile occupant protection restraint device, and has good gas ignitability by adjusting the oxygen balance of the explosive charge molded article. .

  The calorific value of the charge transfer molding of the present invention increases in proportion to the content of the metal powder in the composition, but in order for a gas generator incorporating the transfer charge molding to operate without problems, It is necessary to be 4500 J / g or more, preferably 6000 J / g or more. The calorific value of the charge transfer product directly affects the ignition performance of the gas generant, so it is better that the calorific value is large, but considering the effect on the cooling parts incorporated in the gas generator. However, it is more preferable to set it to 7500 J / g or less.

The explosive charge molding of the present invention is not a powder or granule, but is a molded product molded by any molding method. The molded article is classified into 1 mm to 10 mm using a sieve having an opening of 1 mm and an opening of 10 mm, and has a bulk density of 0.90 to 1.20 g / cm ³ , preferably an opening of 1 mm and an opening of 8 mm. It is classified to 1 to 8 mm using a sieve, and the bulk density is 1.00 to 1.15 g / cm ³ . When the molded product is smaller than 1 mm, the bulk density is small, and a necessary amount cannot be filled with the gas generator, and sufficient ignition performance cannot be obtained. Further, since the combustion rate is high, the preferred combustion rate range of the present invention is not satisfied, and good ignition performance cannot be obtained. Further, even when the molded product is larger than 10 mm, the bulk density is similarly small, and a necessary amount cannot be filled with the gas generator, and sufficient ignition performance cannot be obtained. Furthermore, since the combustion speed is slow, it is out of the preferred combustion speed range of the present invention, and good ignition performance cannot be obtained.

  The burning rate of the explosive charge molding of the present invention is usually 50 to 350 m / sec, preferably 100 to 250 m / sec. If it is out of this range, an ignition delay occurs regardless of whether it is fast or slow. The burning rate is measured by an optical fiber method after filling an inductive steel tube with an explosive compact. This will be described in detail in the examples described later.

Transfer charge molded article of the present invention, the molded product per one 10 to 150 mm ² / number, more preferably a molded body having a 15~100mm ² / number of surface area, as long as the outside these ranges, ignition Delay occurs and good ignition performance cannot be obtained.

  As a general molding method of the explosive charge molding of the present invention, for example, rolling granulation method, extrusion molding method, compression molding method, crushing granulation method, stirring granulation method, fluidized bed granulation method, spray drying granulation Although not limited to these molding methods, it is preferable to use an extrusion molding method, a compression molding method, or a melt solidification granulation method in the present invention.

  The shape of the explosive charge molded body of the present invention is usually not required to have a small surface area such as powder or granules. Specifically, pills, tablets, pellets, clinker, briquettes, single-hole cylindrical shapes, Examples thereof include a porous cylindrical shape. When the shape is a pellet, the diameter of the transfer charge molded body of the present invention is preferably 1 to 10 mm, more preferably 1 to 8 mm, and the length is preferably 1 to 10 mm, and more preferably 1 to 8 mm.

  The particle size of each component used for the transfer powder molded body of the present invention will be described. Preferred particle sizes of each component are 50% particle size of 1 to 30 μm for nitrogen-containing organic compounds, 50% particle size of 20 to 100 μm for oxidizing agents, and 50% particle size of 0.5 to 20 μm for metal powders, More preferably, the nitrogen-containing organic compound has a 50% particle size of 10 to 20 μm, the oxidizing agent has a 50% particle size of 40 to 70 μm, and the metal powder has a 50% particle size of 1 to 15 μm.

  The explosive charge molding of the present invention can contain at least one molding binder. Any molding binder can be used as long as it does not have a significant adverse effect on the combustibility of the charge transfer product.

  The gunpowder composition of the present invention can contain at least one molding binder. Any molding binder may be used as long as it does not have a significant adverse effect on the combustibility of the charge transfer agent. Examples of the molding binder include a metal salt of carboxymethyl cellulose, hydroxypropyl cellulose, cellulose acetate, Cellulose propionate, cellulose acetate butyrate, nitrocellulose, microcrystalline cellulose, guar gum, polyvinyl alcohol, polyvinylpyrrolidone, polyacrylamide, starch and other polymer binders, stearates and other organic binders, molybdenum disulfide, synthetic hydroxy Mention may be made of inorganic binders such as talcite, acid clay, talc, bentonite, diatomaceous earth, kaolin, silica and alumina. Of these, hydroxypropylcellulose, polyvinylpyrrolidone, polyacrylamide, acidic clay, kaolin, and synthetic hydroxytalcite are preferably used from the viewpoints of heat resistance and moldability, and the combination of two or more of these is more effective. Nitrocellulose can be used, for example, dissolved in isoamyl nitrite.

  The inorganic binder is effective as a molding binder that can be used in the present invention because the combustion rate can be adjusted by adding the inorganic binder without affecting the combustion gas. Further, the combined use with the organic binder can reduce the amount of the organic binder used that affects the combustion gas component.

  The molding binder is selected according to the molding method. The content of the molding binder that can be used in the present invention is preferably 2 to 15% by weight, more preferably 2 to 10% by weight. When the content of the molding binder is less than 2% by weight, the strength of the molded product is reduced, the combustion rate is increased, and the object of the present invention cannot be achieved. When the content of the molding binder exceeds 15% by weight, an ignition delay occurs because the combustion rate becomes extremely slow. Also, a large amount of harmful gas such as carbon monoxide is generated.

  The explosive charge molding of the present invention can contain a molding aid, if necessary. In the case of compression molding, the molding aid is used, for example, to prevent a part of the compressed product from adhering to the compression ridge, and in the case of extrusion molding, for example, to reduce the extrusion pressure. It is added to facilitate the production of the molded body. Examples of the molding aid include organic compounds used in the above binder. The difference from the binder is the amount added. In the case of the binder, at least 2% by weight is necessary to exert its performance, but when used as a molding aid, the performance is increased. Is less than 2% by weight, preferably about 0.2 to 1.5% by weight.

  The explosive charge molding of the present invention can contain an autoignition expression catalyst, if necessary. Examples of the autoignition expression catalyst include molybdenum trioxide. The content (ratio) of the autoignition-expressing catalyst in the explosive molding is preferably in the range of 0.2 to 10% by weight.

  Next, the preferable combination of each component in the explosive charge molded object of this invention is demonstrated. It is most preferable to use boron as the metal powder and 5-aminotetrazole as the nitrogen-containing organic compound, and it is most preferable to use potassium nitrate as the oxidizing agent. As the molding binder, A) hydroxypropylcellulose, B) polyvinylpyrrolidone, polyacrylamide, C) acidic clay, kaolin, and synthetic hydroxytalcite are preferable. In the molding binder, A) component is 30 to 70% by weight, The component B) is preferably 0 to 35% by weight, and the component C) is preferably 0 to 40% by weight. And the preferable composition ratio of each component is 3 to 20% by weight of 5-aminotetrazole, 5 to 30% by weight of boron, 50 to 85% by weight of potassium nitrate, and 2 to 15% by weight of the binder for molding, More preferably, 5-aminotetrazole is 5 to 15% by weight, boron is 10 to 20% by weight, potassium nitrate is 65 to 80% by weight, and a molding binder is 2 to 10% by weight. And in this composition ratio range, the calorific value is preferably at least 4500 J / g or more, more preferably 6000 J / g or more.

  Next, the manufacturing method of the explosive charge molded object of this invention is demonstrated. The explosive charge molding of the present invention can be implemented by any method such as compression molding and extrusion molding. In addition, by performing heat processing at 80-110 degreeC after shaping | molding, a transfer agent molded object can fully be dried, and the prevention of the ignition delay resulting from a water | moisture content and the improvement of environmental resistance can be fulfilled.

  First, in the case of compression molding, a metal powder, a nitrogen-containing organic compound and an oxidizing agent, and if necessary, a predetermined amount of a molding binder and a molding aid are weighed and mixed uniformly with a V-type mixer, and then directly in powder form. The composition is put into a compression molding machine, or a solvent is added to the mixed powder, granulation is performed, and heat treatment is performed to obtain a granular explosive charge. can get. In any case, the obtained transfer charge molded body is subjected to heat treatment, classified, and used as a transfer charge molded body.

  When performing extrusion molding, each component is similarly weighed in a spiral mixer, and 8 to 25% by weight of water or an organic solvent (preferably acetone, toluene, cyclopentanone, ethyl acetate, isoamyl acetate, etc.), Alternatively, a mixed solvent of alcohol (preferably ethanol) -water (preferably ion-exchanged water) is added and sufficiently kneaded to obtain a viscous moistening agent. Thereafter, it is extruded into a desired shape using a vacuum kneading extrusion molding machine, appropriately cut, then subjected to heat treatment, classified, and the obtained extrusion molded body is used as a transfer powder molded body.

  Next, the gas generator of the present invention will be described with reference to FIG. FIG. 1 is a cross-sectional view of a gas generator. The gas generator 1 of the present invention includes an upper lid 6, a lower lid 10, a central ignition means 7 in which an igniter 2 and a transfer charge 3 are arranged, and a combustion chamber 8 filled with a gas generating agent 4 around the center. And a cooling filter member 9. The gas generator 1 is suitably used mainly for a vehicle occupant protection device such as for a driver's seat.

  The structure of the gas generator 1 will be specifically described. The upper lid 6 and the lower lid 10 are made of a metal such as iron, stainless steel, aluminum, or steel material. The upper lid 6 and the lower lid 10 are joined by pressure welding and welding. A plurality of gas discharge holes 11 are formed in the upper lid 6. A rupture member 12 such as a strip-shaped aluminum tape is attached to the gas discharge hole 11 from the combustion chamber 8 side to seal the inside of the combustion chamber 8.

  The ignition means 7 provided in the center includes a bottomed inner cylinder 13 having a plurality of fire transfer holes 15 in the periphery, a charge transfer 3 loaded in the inner cylinder 13, and the transfer charge 3. It is comprised with the igniter 2 provided so that it might contact. The charge transfer agent 3 of the present invention is used. The inner cylinder 13 is fixed to the ignition means holding part by a method such as caulking.

  A filter member 9 is provided in the upper lid 6 and the lower lid 10. The cooling filter member 9 is manufactured at low cost by, for example, forming an aggregate of a knitted wire mesh, a plain woven wire mesh, a crimp woven metal wire, or a wound metal wire into an annular shape.

  A filter pressing member 5 is provided in the periphery of the gas discharge hole 11 on the outer peripheral portion of the cooling filter member 9. The filter pressing member 5 is a plate-like member in which a plurality of holes called so-called punching metal are formed in a ring shape. Thus, by providing the filter holding member 5 on the outer peripheral portion of the cooling filter member 9 in the peripheral portion of the gas discharge hole 11, the deformation of the cooling filter member 9 due to the pressure when the gas is released is suppressed.

  A gas generating agent 4 is loaded in the inner peripheral portion of the cooling filter member 9 to form a combustion chamber 8. These gas generating agents 4 are burned by the flame and hot particles from the ignition means 7.

  The gas generating agent 4 will be described. The gas generating agent 4 is usually composed of a fuel component, an oxidant, and an additive.

  Examples of the fuel component include nitrogen-containing organic compounds, and examples of the nitrogen-containing organic compounds include one or a mixture of two or more selected from triazole derivatives, tetrazole derivatives, guanidine derivatives, azodicarbonamide derivatives, and hydrazine derivatives. .

  Examples of the triazole derivative include 5-oxo-1,2,4-triazole.

  Examples of the tetrazole derivatives include tetrazole, 5-aminotetrazole, aminotetrazole nitrate, nitroaminotetrazole, 5,5′-bi-1H-tetrazole, 5,5′-bi-1H-tetrazole diammonium salt, 5,5 Examples include '-azotetrazole diguanidinium salt.

  Examples of the guanidine derivative include guanidine, nitroguanidine, cyanoguanidine, triaminoguanidine nitrate, guanidine nitrate, aminoguanidine nitrate, and guanidine carbonate.

  Examples of the azodicarbonamide derivative include biuret and azodicarbonamide.

  Examples of the hydrazine derivative include carbohydrazide, carbohydrazide nitrate complex, oxalic acid dihydrazide, hydrazine nitrate complex, and ammine complex.

  In the present invention, a guanidine derivative having poor reactivity (poor ignitability), specifically, a gas generating agent using guanidine nitrate, aminoguanidine nitrate, guanidine carbonate, triaminoguanidine nitrate, or nitroguanidine as a fuel component is used. In these cases, it is particularly effective. Of these, guanidine nitrate is inexpensive and contains a high number of moles because it contains oxygen atoms in the molecule and requires less oxidant for complete combustion. Also, it has a high negative standard production enthalpy ΔHf, and as a result, the amount of energy released during combustion of the gas generant is small, the combustion temperature of the gas mixture can be kept low, and as a fuel for gas generant Is preferred.

  The mixing ratio of the nitrogen-containing organic compound in the gas generating agent varies depending on the number of carbon atoms, hydrogen atoms and other atoms to be oxidized in the molecular formula, but is usually in the range of 20 to 70% by weight, preferably 30 to 60%. A weight percent range is particularly preferred. The absolute value of the compounding ratio of the nitrogen-containing organic compound varies depending on the type of oxidizing agent in the gas generating agent, but if it exceeds the theoretical amount of complete oxidation, the concentration of trace carbon monoxide in the generated gas increases, and the theoretical amount of complete oxidation and Below that, the trace nitrogen oxide concentration in the generated gas increases. Therefore, the range in which the optimum balance between the two is maintained is most preferable.

  As the oxidizing agent, an oxidizing agent selected from at least one of nitrates, nitrites, and perchlorates containing a cation selected from alkali metals, alkaline earth metals, transition metals, and ammonium is preferable. Oxidizing agents other than nitrates, that is, oxidizing agents that are frequently used in the field of gas generators for airbags, such as nitrite and perchlorate, can be used, but the number of oxygen in the nitrite molecule is reduced compared to nitrate. Nitrate is more preferable from the standpoint of reducing the production of fine mist that is easily released out of the bag or the like.

  Examples of the nitrate include sodium nitrate, potassium nitrate, magnesium nitrate, strontium nitrate, phase-stabilized ammonium nitrate, basic copper nitrate, and the like, and strontium nitrate, phase-stabilized ammonium nitrate, and basic copper nitrate are particularly preferable.

  The blending ratio of the oxidizing agent in the gas generating agent varies in absolute value depending on the type and amount of the nitrogen-containing organic compound used, but is preferably in the range of 30 to 80% by weight, particularly the above-mentioned carbon monoxide and nitrogen oxides. A range of 40 to 75% by weight in relation to the concentration is preferred.

  Examples of the additive include a binder, a molding aid, a slag forming agent, and a combustion adjusting agent.

  Any binder can be used as long as it does not have a significant adverse effect on the combustion behavior of the gas generating agent. Examples of the binder include polymer compounds such as metal salts of carboxymethyl cellulose, hydroxyethyl cellulose, cellulose acetate, cellulose propionate, cellulose acetate butyrate, nitrocellulose, microcrystalline cellulose, guar gum, polyvinyl alcohol, polyvinyl pyrrolidone, polyacrylamide, and starch. And organic binders such as stearate, inorganic binders such as molybdenum disulfide, synthetic hydroxytalcite, acid clay, talc, bentonite, diatomaceous earth, kaolin, silica, and alumina.

  The blending ratio of the binder in the gas generating agent 4 is preferably in the range of 2 to 10% by weight in the case of compression molding, and is preferably in the range of 2 to 15% by weight in the extrusion molding. Although the fracture strength of the compact becomes stronger on the larger quantity side, the number of carbon atoms and hydrogen atoms in the gas generating agent 4 increases, and a trace amount of carbon monoxide which is an incomplete combustion product of carbon atoms. Since the concentration of the gas increases, the quality of the generated gas is lowered, and combustion is inhibited, the use of the minimum amount is preferable. In particular, if the amount exceeds 15% by weight, the relative proportion of the oxidizing agent needs to be increased, and the relative proportion of the gas generating agent 4 decreases, making it difficult to establish a practical gas generator system.

  In the case of compression molding, the molding aid is used, for example, to prevent a part of the compressed product from adhering to the compression ridge, and in the case of extrusion molding, for example, to reduce the extrusion pressure. It is added to facilitate the production of the molded body. Examples of the molding aid include organic compounds used in the above binder. The difference from the binder is the amount added. In the case of the binder, at least 2% by weight is necessary to exert its performance, but when used as a molding aid, the performance is increased. Is less than 2% by weight, preferably about 0.2 to 1.5% by weight.

  The slag forming agent is added to facilitate filtration through a filter in the gas generator 1 due to the interaction with the metal oxide generated from the oxidant component in the gas generating agent 4 in particular.

  Examples of the slag forming agent include naturally occurring clay, synthetic mica, synthetic kaolinite, synthetic smectite, etc., mainly composed of aluminosilicates such as silicon nitride, silicon carbide, acid clay, silica, bentonite and kaolin. Examples include artificial clay and talc which is a kind of hydrous magnesium silicate mineral. Among these, acidic clay or silica is preferable, and acidic clay is particularly preferable.

  The blending ratio of the slag forming agent is preferably in the range of 0 to 20% by weight, particularly preferably in the range of 2 to 10% by weight. If the amount is too large, the linear combustion rate is lowered and the gas generation efficiency is lowered. If the amount is too small, the slag forming ability cannot be sufficiently exhibited.

  As the combustion modifier, for example, metal oxides, ferrosilicon, activated carbon, graphite, or compound explosives such as hexogen, octogen, 3-nitro-1,2,4-triazole can be used. The metal oxide is preferably copper oxide, iron oxide, cobalt oxide, manganese dioxide, zinc oxide or the like.

  The blending ratio of the combustion modifier is preferably in the range of 0 to 20% by weight, particularly preferably in the range of 2 to 10% by weight. If the amount is too large, the gas generation efficiency is lowered. If the amount is too small, a sufficient combustion rate cannot be obtained.

  Examples of the shape of the gas generating agent 4 include pills, tablets, pellets, briquettes, single-hole cylindrical shapes, porous cylindrical shapes, and disk shapes.

  The gas generator 1 is mainly incorporated in an airbag module to be mounted in an instrument panel on the driver's seat as a one-tube type gas generator. When attached to the airbag module, it can be attached by fixing the flange 14 to the module.

  And after incorporating in an airbag module, the ignition means 7 of the gas generator 1 is connected to the vehicle side connector which is not illustrated.

  As described above, the gas generator 1 mounted on the automobile has the ignition means 7 operated by the squib ignition circuit connected to the ignition means 7 when the collision sensor detects a collision of the automobile, for example. The gas generating agent 4 in the combustion chamber 8 is burned to generate a high temperature gas. At this time, the pressure in the combustion chamber 8 increases. The hot gas generated in the combustion chamber 8 passes through the cooling filter member 9, breaks the rupture member 12, and is discharged from the gas discharge hole 11. When the high temperature gas passes through the cooling filter member 9, the gas is cooled and the residue is collected. In addition, since the cooling filter member 9 is provided over substantially the entire combustion chamber 8, the cooling filter member 9 can be used effectively. For this reason, it becomes possible to discharge | release the gas by which it fully cooled and the residue was fully collected.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these.

Example 1
Boron fine powder: 12.0 parts by weight was weighed into a spiral mixer, and ethanol: 3.0 parts by weight / ion exchanged water: 15.0 parts by weight of ethanol water was added and mixed to form a slurry. Separately, 5-aminotetrazole (50% particle size, 15 μm): 11.0 parts by weight, potassium nitrate (50% particle size, 60 μm): 70.5 parts by weight, acid clay (50% particle size, 17 μm): 1. 5 parts by weight, hydroxypropyl cellulose {trade name; Metroz 90SH-100000 (manufactured by Shin-Etsu Chemical Co., Ltd.)}: 3.0 parts by weight, polyvinylpyrrolidone {trade name; rubiscol K90 (manufactured by BASF)}: 2 0.0 part by weight was dry mixed with a V-type mixer. Next, this mixture was kneaded with a spiral mixer to obtain a wet kneading agent. This kneading agent was put into a vacuum kneading extruder, extruded through a die having a diameter of 1.8 mm, and cut at a length of 2.5 mm (molded body surface area: 19.2 mm ² / piece). This was dried at 55 ° C. for 8 hours, then at 110 ° C. for 8 hours, classified using a 1 mm sieve and a 2.8 mm sieve to remove powder and irregular shapes, and on a 1 mm sieve. In addition, an explosive charge molding of the present invention was obtained.

Example 2
5-aminotetrazole (50% particle size, 15 μm): 11.7 parts by weight, boron fine powder (50% particle size, 9 μm): 16.7 parts by weight, molybdenum trioxide (50% particle size, 17 μm): 1 0.5 part by weight was dry mixed with a V-type mixer. Subsequently, 50 parts by weight (concentration: 2% by weight) of an isoamyl acetate solution of nitrocellulose (1 part by weight in terms of nitrocellulose) was added, and the mixture was further mixed into a slurry in a mortar. To this, potassium nitrate (50% particle size, 60 μm): 70.1 parts by weight was added and further mixed until uniform. Thereafter, isoamyl acetate was evaporated, passed through a mesh of 1 mm, and dried at 110 ° C. for 5 hours to obtain a granular explosive. This granular explosive was molded into a diameter of 6.0 mm and a length of 2.0 mm using a tableting machine (molded body surface area: 94.2 mm ² / piece), and further dried at 110 ° C. for 3 hours. Then, the mixture was classified using a sieve having an opening of 1 mm and a sieve of 6.5 mm, and powders and irregularly shaped products were removed, and a transfer charge molded article of the present invention was obtained on the sieve having an opening of 1 mm.

Example 3
Boron fine powder: 12.0 parts by weight was weighed into a spiral mixer, and ethanol: 3.0 parts by weight / ion exchanged water: 15.0 parts by weight of ethanol water was added and mixed to form a slurry. Separately, 5-aminotetrazole (50% particle size, 15 μm): 11.0 parts by weight, potassium nitrate (50% particle size, 60 μm): 70.5 parts by weight, synthetic hydrotalcite (50% particle size, 17 μm): 2.0 parts by weight, hydroxypropylcellulose {trade name; Metros 90SH-100000 (manufactured by Shin-Etsu Chemical Co., Ltd.)}: 3.5 parts by weight, polyvinylpyrrolidone {trade name; rubiscol K90 (manufactured by BASF)} : 1.0 part by weight was dry-mixed with a V-type mixer. Next, this mixture was kneaded with a spiral mixer to obtain a wet kneading agent. This kneading agent was put into a vacuum kneading extruder, extruded through a die having a diameter of 1.8 mm, and cut at a length of 2.5 mm (molded body surface area: 19.2 mm ² / piece). This was dried at 55 ° C. for 8 hours, then at 110 ° C. for 8 hours, classified using a 1 mm sieve and a 2.8 mm sieve to remove powder and irregular shapes, and on a 1 mm sieve. In addition, a fire transfer chemical molding of the present invention was obtained.

Comparative Example 1
Boron nitrate generally used as an explosive composition was prepared by the following procedure. Boron fine powder: 25.0 parts by weight and potassium nitrate: 75.0 parts by weight, 50 parts by weight of nitrocellulose isoamyl acetate solution (concentration: 2% by weight) (1 part by weight in terms of nitrocellulose) is added, and further in a mortar Mix until in slurry form. Thereafter, isoamyl acetate was evaporated and passed through a sieve having an opening of 1 mm to form granules. This was dried at 110 ° C. for 5 hours to obtain a granular boron nitrate transfer powder.

Comparative Example 2
5-aminotetrazole (50% particle size, 15 μm): 11.7 parts by weight, boron fine powder (50% particle size, 9 μm): 16.7 parts by weight, molybdenum trioxide (50% particle size, 17 μm): 1 0.5 part by weight was dry mixed with a V-type mixer. Subsequently, 50 parts by weight (concentration: 2% by weight) of an isoamyl acetate solution of nitrocellulose (1 part by weight in terms of nitrocellulose) was added, and the mixture was further mixed into a slurry in a mortar. To this, potassium nitrate (50% particle size, 60 μm): 70.1 parts by weight was added and further mixed until uniform. Thereafter, isoamyl acetate was evaporated, passed through a sieve having an opening of 1 mm, and dried at 110 ° C. for 5 hours to obtain a granular transfer charge.

Measurement of calorific value and burning rate measurement of transfer powder molded body Using each of the transfer powders obtained in Examples 1, 2, and 3 and Comparative Examples 1 and 2, the calorific value, bulk density and burning rate of these were determined. Measured and compared. Table 1 summarizes the results of calorific value, bulk density and burning rate.

Bulk Density Measurement Regarding the transfer charge molded bodies obtained in Examples 1, 2, and 3, and Comparative Examples 1 and 2, the bulk density was measured using a bulk density measuring instrument (ABD powder property measuring instrument, manufactured by Tsutsui Rika Kikai Co., Ltd.). Density was measured.

Calorific value measurement The calorific value was measured with a bomb calorimeter. In an airtight container made of SUS, 1.0 g of each explosive obtained in Examples 1, 2, and 3, and Comparative Examples 1 and 2 was weighed, and the lid was closed with the nichrome wire in contact therewith. This was put into a heat-insulating container filled with water, and a nichrome wire was energized to ignite it, thereby burning the composition completely. The calorific value was calculated from the temperature of the raised water and the specific heat.

Burning rate measurement The burning rate was measured by the optical fiber method for the granular charge obtained in Comparative Examples 1 and 2 and the formed charge transfer product of the present invention (Examples 1, 2 and 3). A 1-inch steel pipe having a length of 300 mm was filled with 120 to 150 g of each explosive charge (depending on the bulk density of the explosive charge), and sealed with a lid equipped with an igniter for a gas generator. Inch steel pipes were inserted with optical fibers at four locations at intervals of 50 mm, and the optical fibers were connected to a measuring instrument with a cable via a light detection device. The igniter was activated, the charge was started, the time required to pass between the optical fibers was measured, and the burning rate was calculated.

Table 1
Shape Bulk density [g / cm ³ ] Calorific value [J / g] Burning rate [m / sec] Example 1 Pellet 1.12 6000 226
Example 2 Pellets 0.98 6400 142
Example 3 Pellets 1.03 5900 240
Comparative Example 1 Granular 0.74 6700 620
Comparative Example 2 Granular 0.70 6400 747

  It can be seen that, compared with the granular charge transfer materials of Comparative Examples 1 and 2, the molded charge transfer products of Examples 1, 2 and 3 have a lower combustion rate. This result can be said to be a charge transfer agent that meets the object of the present invention to increase the combustion time of the transfer charge and improve the ignitability. In addition, the calorific value is the same for any explosive charge. Using these explosives, the ignition performance for the gas generating agent was confirmed by the following 60 L tank test.

Measurement of ignitability of transfer powder to gas generant (from 60L tank test)
A 60 L tank test was conducted using the gas generator 1 shown in FIG. 1, and the ignitability of the charge transfer agent with respect to the gas generating agent was examined. This time, in order to confirm the ignitability in a low temperature environment, this gas generator 1 is left at −40 ° C. for 4 hours, and then attached to a sealed container with an internal volume of 60 liters. Was measured. Here, as shown in FIG. 2, P ₁ is the maximum pressure reached in the container, t ₁ is the time from energization of the ignition device to the operation of the gas generator, and t ₂ is the pressure from the operation of the gas generator. It represents the time until P ₁ is obtained. For ignition performance of the transfer charge is cold test, it is required for the time t ₁ is within 10 ms, if it exceeds this range, the gas generator generates a operation delay, it does not exhibit sufficient performance. Here, it indicates the time t ₁ from the power supply to the igniter up to the operation of the gas generator.

The 60 L tank test results are summarized in Table 2. In addition, the usage-amount of explosive was 1.1g.
The gas generating agent in the gas generator 1 used in the 60 L tank test was guanidine nitrate (50% particle size, 10 μm): 40.6 parts by weight, strontium nitrate (50% particle size, 13 μm): 25.0 Parts by weight, basic copper nitrate (50% particle size, 5 μm): 25.0 parts by weight, acid clay (50% particle size, 17 μm): 5.0 parts by weight and graphite as a combustion catalyst (50% particle size, 5 μm) ): 0.5 parts by weight, hydroxypropylcellulose: 2.3 parts by weight, and polyvinylpyrrolidone: 1.6 parts by weight were dry-mixed using a V-type mixer. Next, the mixed powder was transferred to a spiral mixer, and ethanol: 3.0 parts by weight / ion exchange water: 13.0 parts by weight of ethanol water was added and kneaded to obtain a wet kneading agent. This kneading agent was put into a vacuum kneading extruder, extruded through a die having a diameter of 2.0 mm, and cut at a drug thickness of 6.5 mm. This was dried at 55 ° C. for 8 hours and then at 110 ° C. for 8 hours to obtain a gas generant tablet. 35 g of this gas generating agent was filled in the gas generator 1 shown in FIG. 1 and used for the test.

Table 2
Gunpowder t ₁ t ₂ P ₁
Shape Diameter Length [mm] [mm] [kPa]
Example 1 Pellet shape 1.8 mm × 2.5 mm 6.1 66.8 144
Example 2 Pellet 6.0 mm × 2.0 mm 6.7 69.6 154
Example 3 Pellet shape 1.8 mm × 2.5 mm 5.8 65.3 148
Comparative Example 1 Granular 14.2 101.5 127 Comparative Example 2 Granular 1.8 No pressure increase

  From the results of Table 2 and FIG. 3 obtained from the 60L tank test, the molded product of the present invention in which the combustion rate was reduced as the molded product showed no combustion delay and good combustion characteristics (Example 1, 2 and 3). In addition, when a granular charge having a high burning rate was used, an ignition delay occurred (Comparative Example 1). In the case of the granular charge of Comparative Example 2, the number of tests was repeated. Some gas generating agents have not started to burn. From the 60L tank test conducted this time, guanidine nitrate, which has poor ignitability, was used as the fuel component of the gas generant, and even in a severe low temperature environment of -40 ° C, the explosive charge compact of the present invention had good ignitability It was confirmed that In the case of granular explosives, the ignitability can be improved by increasing the amount used, but it is not preferable for gas generators in terms of the amount of heat generated by combustion of explosives and the residue of combustion. Direction. As is clear from Examples 1 to 3, it is possible to provide a gas generator having a reliable ignition performance with a small dose by using the transfer powder molded body of the present invention.

It is a principal part cross-sectional schematic diagram which shows the structure of the gas generator used by the 60L tank test. It is a graph which shows the combustion state of the 60L tank test obtained by operating the gas generator using the transfer agent molded object of this invention by the relationship between time and pressure. It is a figure which shows the result of the 60L tank test in the gas generator using the gunpowder molding of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Gas generator 2 Igniter 3 Gunpowder 4 Gas generating agent 5 Filter holding member 6 Upper cover 7 Ignition means 8 Combustion chamber 9 Cooling filter member 10 Lower cover 11 Gas discharge hole 12 Rupture member 13 Inner cylinder 14 Flange 15 Fire transfer Hole P ₁ Maximum ultimate pressure t ₁ Time to start operation t ₂ Time from operation to P ₁

Claims (8)

It contains each of the following components (a), (b), and (c), the calorific value is 4500 J / g or more, it is classified into 1 to 10 mm, and the bulk density is 0.90 to 1.20 g / cm ^3. Is a charge transfer molding.
(A) Metal powder (b) Nitrogen-containing organic compound (c) Oxidizing agent The explosive charge molding according to claim 1, wherein the burning rate is 50 to 350 m / sec. The transfer charge molded article according to claim 1 or 2, wherein a surface area per molded article is 10 to 150 mm ² / piece. The metal charge powder molded body according to any one of claims 1 to 3, wherein the metal powder is at least one selected from boron, aluminum, magnesium, magnalium, silicon, titanium, titanium hydride and zirconium. The transfer agent molded article according to any one of claims 1 to 4, wherein the nitrogen-containing organic compound is at least one selected from a tetrazole derivative, a guanidine derivative, a hydrazine derivative, and a metal complex. The transfer agent molded body according to any one of claims 1 to 5, wherein the oxidizing agent is at least one selected from the group consisting of potassium nitrate, sodium nitrate, and strontium nitrate. The tetrazole derivative is used in an amount of 3 to 20 wt%, the boron is used in an amount of 5 to 30 wt%, the potassium nitrate is used in an amount of 50 to 85 wt%, and a molding binder is used in an amount of 2 to 15 wt%. No charge charge molding. A gas generator for an automobile occupant protection device comprising the explosive charge molding according to any one of claims 1 to 7.

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