Gas generating agent and airbag

Abstract

The invention discloses a gas generating agent and a safety airbag. The gas generating agent comprises a combustible agent, an oxidizing agent and a framework composition; the backbone composition includes a combination of carbides, and metal nitrates and / or metal oxides. The gas generating agent is prepared by combining the substances, and a large amount of gas is emitted by utilizing rapid combustion of the combustible agent and the oxidizing agent, so that the interior of the air bag is rapidly inflated; the framework composition in the gas generating agent can quickly form a smoke and fire framework in an integral block shape after combustion, on one hand, the smoke and fire framework has an integral block-shaped structure, so that the weight of a filter screen can be reduced, or the filter screen is not used, and on the other hand, the smoke and fire framework can also adsorb smaller combustion residues, so that the gas discharged into the air bag is cleaner.

Description

Technical Field

[0001] The invention relates to the technical field of automobile safety equipment, and in particular to a gas generating agent and a safety airbag. Background Art

[0002] As people's quality of life improves, cars become more and more popular, and car safety issues are increasingly concerned by consumers. As the core component of automobile airbags, the types and performance requirements of gas generators are becoming more and more perfect. However, no matter what type of gas generator, it must meet the following requirements: safe and reliable, timely action; under high and low temperature environments, the relevant functions should meet the requirements of the automobile airbag gas generator industry; the generated gas is basically non-toxic and non-corrosive, and does not harm the occupants; the gas temperature is as low as possible to prevent fire or burns; meet equipment and storage requirements; low residue rate, high gas production rate, etc.

[0003] In the prior art, most gas generators will produce a large amount of residue after use. These residues are small in size and difficult to filter. They will enter the airbag body through the filter, thus causing harm to the human body. Therefore, how to provide a gas generator that produces less residue after use and can be filtered by the filter becomes the key. Summary of the invention

[0004] The purpose of the present invention is to provide a gas generating agent and a safety airbag, which can solve the problem that the residue generated by the gas generating agent after use is difficult to filter.

[0005] To achieve the purpose of the present invention, the present invention provides the following technical solutions:

[0006] In a first aspect, the present invention provides a gas generating agent, comprising a combustible agent, an oxidant, and a skeleton composition; the skeleton composition comprises a carbide, and a combination of metal nitrates and / or metal oxides.

[0007] In one embodiment, the carbide includes boron carbide and / or silicon carbide; the metal nitrate includes potassium nitrate, sodium nitrate, and strontium nitrate; and the metal oxide includes at least one of magnesium oxide, aluminum oxide, calcium oxide, cobalt oxide, and zirconium oxide.

[0008] In one embodiment, the mass ratio of the carbide, the metal nitrate, and the metal oxide satisfies the stoichiometric ratio of the chemical reaction equation of the three.

[0009] In one embodiment, the combustible agent includes a combination of one or more of nitroguanidine, guanidine nitrate, pentaaminotetrazole, guanyl urea copper nitrate and melamine.

[0010] In one embodiment, the oxidant includes a main oxidant, and the main oxidant includes a combination of one or more of basic copper nitrate, copper oxide, iron oxide, and ammonium nitrate.

[0011] In one embodiment, the oxidant includes an auxiliary oxidant, and the combustion rate of the auxiliary oxidant is greater than the combustion rate of the main oxidant.

[0012] In one embodiment, the auxiliary oxidant includes potassium perchlorate, ammonium perchlorate, or a combination of both.

[0013] In one embodiment, the proportions of the main oxidant and the auxiliary oxidant in the gas generating agent are as follows, by mass percentage: 20% to 50% for the main oxidant and 1% to 10% for the auxiliary oxidant.

[0014] In one embodiment, the proportions of the components in the gas generant are as follows, by mass percentage: 30% to 60% of the combustible agent, 21% to 60% of the oxidant, and 0.1% to 10% of the skeleton composition.

[0015] In a second aspect, the present invention provides an airbag, comprising an airbag body and the gas generating agent described in the first aspect, wherein the gas generating agent is disposed in the airbag body.

[0016] The present invention combines the above substances into a gas generating agent, utilizes the rapid combustion of the combustible agent and the oxidant to emit a large amount of gas, thereby rapidly inflating the interior of the airbag; the skeleton composition in the gas generating agent will rapidly form a pyrotechnic skeleton having an overall block shape after combustion; on the one hand, the pyrotechnic skeleton having an overall block structure can reduce the weight of the filter, or eliminate the use of the filter, thereby replacing the filter in the prior art and reducing the manufacturing cost of the airbag; on the other hand, the pyrotechnic skeleton can also absorb smaller combustion residues, thereby making the gas discharged into the airbag bag cleaner. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 is an appearance diagram of the gas generating agent of the embodiment and the comparative example;

[0019] Figure 2 It is a diagram showing the appearance of the gas generating agents of the examples and comparative examples after combustion. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used in the present invention includes any and all combinations of one or more of the related listed items.

[0022] Some embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0023] The present invention provides a gas generator for use in a safety airbag, wherein the gas generator includes a combustible, an oxidant, and a skeleton composition; the skeleton composition includes a carbide, and a combination of metal nitrates and / or metal oxides. The present invention combines the above substances to form a gas generator, and utilizes the rapid combustion of the combustible and the oxidant to emit a large amount of gas, thereby rapidly inflating the interior of the airbag; the skeleton composition in the gas generator will rapidly form a pyrotechnic skeleton with an overall block shape after combustion. On the one hand, the pyrotechnic skeleton has an overall block structure that can reduce the weight of the filter, or do not use the filter, thereby replacing the filter in the prior art to reduce the manufacturing cost of the airbag, and on the other hand, the pyrotechnic skeleton can also absorb smaller combustion residues, so that the gas discharged into the airbag bag is cleaner.

[0024] In one embodiment, the carbide includes boron carbide and / or silicon carbide; the metal nitrate includes at least one of potassium nitrate, sodium nitrate, and strontium nitrate; and the metal oxide includes at least one of magnesium oxide, aluminum oxide, calcium oxide, cobalt oxide, and zirconium oxide.

[0025] In a specific embodiment, the skeleton composition may include carbides and metal nitrates. The carbides may react with metal nitrates to form metal borates or metal silicates, which may form molten glass bodies. The tiny particles generated by the combustion of the system are easily adsorbed by the molten glass bodies to form a network structure, which forms a glass-like overall pyrotechnic skeleton after combustion and cooling.

[0026] In a specific embodiment, the skeleton composition may include carbides and metal oxides. Carbides can react with metal oxides to form a glass with a higher melting point, such as metal borates or metal silicates. Because common alkaline earth metal oxides can form a glass with a higher melting point, wherein the alkaline earth metal oxides can be a single or a mixture, and the high melting point oxide can keep the gas generating agent in shape after combustion, and adsorb microparticles to the maximum extent.

[0027] In a specific embodiment, the skeleton composition may include carbides, metal nitrates and metal oxides. In an oxygen atmosphere, carbides can react with metal nitrates and metal oxides at the same time to obtain a glass body. The advantage of using metal nitrates and metal oxides to react with carbides at the same time is that the product after the reaction of carbides and metal nitrates is also acidic. On the one hand, the reaction product can dissolve part of the metal oxide to intensify the reaction process. On the other hand, the reaction product can also catalyze the overall combustion efficiency of the gas generator, so that the gas generator reacts quickly after starting to burn to form a stable pyrotechnic skeleton and produce a large amount of gas.

[0028] In other embodiments, hydroxides may be used to replace oxides in the gas generator, such as aluminum hydroxide, bismuth hydroxide, etc. The purpose of using hydroxides to form the gas generator is the same as that of metal oxides. The stability of hydroxides is better than that of metal oxides because hydroxides are not easy to absorb water and deteriorate.

[0029] In one embodiment, the mass ratio of the carbide, the metal nitrate, and the metal oxide satisfies the stoichiometric ratio of the chemical reaction equation of the three.

[0030] In a specific embodiment, the carbide is boron carbide and the metal nitrate is sodium nitrate. The reaction equation of boron carbide and sodium nitrate is as follows:

[0031] 2B4C+4NaNO3+3O2=2Na2B4O7+2CO2+2N2

[0032] Among them, O2 comes from the oxygen provided by the combustion of the gas generating agent system, B4C burns in the system to generate B2O3, and the acidic B2O3 decomposes with alkali metals such as sodium nitrate to form an oxide to generate tetraborate glass (sodium tetraborate), which can produce a large amount of gas and is also used to inflate the airbag. Therefore, in the system of the above chemical reaction equation, the stoichiometric ratio of carbide and metal nitrate is 2:4.

[0033] In the prior art, tetraborate glass is usually added directly to the gas generator to absorb the residue. However, it is difficult to implement because the tetraborate glass has strong hygroscopicity. In addition, some metal salts are also harmful substances and are prohibited substances in gas generators.

[0034] The present invention adopts a scheme of in-situ generation of glass body by raw materials of tetraborate glass body under the high temperature condition of gunpowder combustion, and no vitrified hygroscopic substance will be produced before combustion is complete, and other substances of the gas generant (such as oxidant and combustible agent) will not contain strong hygroscopic substances before ignition, thereby avoiding the rupture of tablets due to moisture, thereby avoiding the situation of rapid increase of the combustion surface and explosion of the chamber.

[0035] In a specific embodiment, the carbide is boron carbide, and the metal oxide may include magnesium oxide, calcium oxide, aluminum oxide, cobalt oxide, and zirconium oxide. Boron carbide generates boron oxide after burning in the system, so the reaction equation of boron oxide and metal oxide is as follows:

[0036] B2O3+MgO=MgB2O4, 2B2O3+CaO=CaB4O7, B2O3+Al2O3=2AlBO3, B2O3+Co2O3=Co2B2O6

[0037] Alternatively, the mixture may exist in a stoichiometric ratio, and the reaction equation is as follows:

[0038] 4B2O3+CaO+MgO+Al2O3=MgB2O4+CaB4O7+2AlBO3

[0039] The mass ratio is B2O3:CaO:MgO:Al2O3=59:12:8:21. Different alkali metal nitrates or alkaline earth metal oxides play different roles in the combustion reaction of the gas generating agent. For example, when the B2O3 content is high, the slag has better formability, the overall pyrotechnic skeleton remains more complete, and the adsorption performance is better. If MgO is added at the same time, it can not only maintain the shape, but also increase the burning rate of the combustion system. Especially after adding BaO, ZrO2, etc., the catalytic effect of the combustion system is significantly promoted.

[0040] In one embodiment, the combustible includes a combination of one or more of nitroguanidine, guanidine nitrate, pentaaminotetrazole, guanyl urea copper nitrate and melamine. The above materials are all explosive materials. Through the reaction of the combustible with the oxidant and the skeleton composition, a large amount of gas can be generated instantly, thereby causing the airbag to expand.

[0041] In one embodiment, the oxidant includes a primary oxidant, and the primary oxidant includes a combination of one or more of basic copper nitrate, copper oxide, iron oxide, and ammonium nitrate.

[0042] In one embodiment, the oxidant further includes an auxiliary oxidant, and the combustion rate of the auxiliary oxidant is greater than the combustion rate of the main oxidant. Adding an auxiliary oxidant that increases the combustion rate can increase the combustion rate of the system.

[0043] It should be explained that the burning speed reflects the amount (mass or volume) of the auxiliary oxidant and the main oxidant burned per unit time. In a specific embodiment, the method for testing the burning speed of the auxiliary oxidant and the burning speed of the main oxidant can be, under the same environmental conditions, using a gas generator with only the main oxidant added and a gas generator with only the auxiliary oxidant added as test objects, and the gas generators are both in the shape of round cakes. Ignite two gas generators at the same time, record the diameter D1 of the gas generator before ignition, and the diameter D2 of the gas generator after ignition and complete combustion, the burning time is T, and the burning speed is V = (D1-D2) / T.

[0044] In one embodiment, the auxiliary oxidant includes potassium perchlorate, ammonium perchlorate, or a combination of the two.

[0045] In a specific embodiment, the gas generating agent may include boron carbide, basic copper nitrate, nitroguanidine and potassium nitrate, and the reaction equation is as follows:

[0046] 0.6B4C+46.3Cu4N2H6O 12 +50.9CH6N4O3+2.2KNO3→2.5K2B4O7+24.6Cu+26.6N2+18.7CO2+27.6H2O

[0047] The potassium tetraborate glass formed in the reaction equation adsorbs the produced Cu particles, thereby achieving the effect of filtering and adsorption. If BaO and ZrO2 are added, solid glass and copper residues will be formed in the form of a whole block.

[0048] In one embodiment, the proportion of the main oxidant and the auxiliary oxidant in the gas generating agent is: 20% to 50% of the main oxidant and 1% to 10% of the auxiliary oxidant by mass percentage. Optionally, the proportion of the main oxidant in the gas generating agent may be 20%, 25%, 30%, 35%, 40%, 45%, 50%. Optionally, the proportion of the auxiliary oxidant in the gas generating agent may be 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%.

[0049] The reason why the proportion of the main oxidant and the auxiliary oxidant is within the above range is to ensure that the main oxidant and the auxiliary oxidant can play a synergistic role to increase the combustion rate of the gas generator and avoid flash explosion caused by too fast combustion of the two. When the proportion of the main oxidant and the auxiliary oxidant is less than the above range, the content of the oxidant mainly used for initiation in the gas generator is reduced, the combustion rate of the gas generator is reduced, and the gas cannot be quickly generated when the airbag is activated. When the proportion of the main oxidant and the auxiliary oxidant is greater than the above range, the proportion of gas substances in the gas generator is reduced, the skeleton composition is difficult to form, and too fast combustion will cause safety hazards.

[0050] In one embodiment, the proportion of each component in the gas generant is calculated by mass percentage: 30% to 60% of the combustible agent, 21% to 60% of the oxidant, and 0.1% to 10% of the skeleton composition. Optionally, the proportion of the combustible agent in the gas generant can be 30%, 35%, 40%, 45%, 50%, 55%, 60%. Optionally, the proportion of the oxidant in the gas generant can be 21%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%. Optionally, the proportion of the skeleton composition in the gas generant can be 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%.

[0051] When the mass ratio of the combustible, oxidant and skeleton composition is within the above range, it can ensure that the gas generating agent burns quickly to generate gas and forms an overall blocky pyrotechnic skeleton, and can also ensure safety during combustion. When the proportion of the skeleton composition is less than the above range, it is difficult to form an overall blocky pyrotechnic skeleton, and the proportion of the combustible and oxidant is too high, and too fast combustion will cause safety hazards. When the proportion of the skeleton composition is greater than the above range, the combustion rate of the gas generating agent decreases, and gas cannot be generated quickly when the airbag is activated.

[0052] In one embodiment, the present invention further provides a method for preparing a gas generating agent, comprising:

[0053] Step S10, mixing a combustible agent, an oxidant, and a skeleton composition to obtain a mixture.

[0054] Step S20, preparing the mixture into mixed particles, and obtaining a gas generating agent after drying and pressing.

[0055] The framework composition includes a combination of carbide, metal nitrate and / or metal oxide.

[0056] Optionally, in step S10, the combustible, the oxidant, and the skeleton composition are mixed to obtain a mixture, including: 1) dissolving the metal nitrate in a solvent and fully dissolving it; 2) adding the carbide to the above solvent and stirring it evenly; 3) adding the combustible, the oxidant, and the optional metal oxide to the above solvent to obtain a mixture.

[0057] Optionally, in step S20, the mixture is made into mixed particles, and a gas generator is obtained after drying and pressing, including: 4) adding alcohol to the mixture, mixing evenly and granulating; 5) drying the obtained particles in a vacuum at 70°C to 80°C; 6) adding a release agent to the dried particles and pressing them into tablets to obtain a gas generator.

[0058] Optionally, the proportion of each component in the gas generating agent can refer to the above embodiment, with the combustible agent being 30% to 60%, the oxidant being 21% to 60%, and the skeleton composition being 0.1% to 10%.

[0059] Optionally, the granules can be made by a granulator, and after granulation, the granules are filtered through a 20-mesh sieve, and the sieve-down is collected and placed in a vacuum oven for drying until the volatile matter is less than 0.4%.

[0060] Optionally, the gas generating agent obtained by tabletting with a tablet press is a tablet of Φ6×1.8 mm.

[0061] In one embodiment, the present invention further provides an airbag, which includes an airbag body and the gas generating agent provided in the above embodiment.

[0062] The technical solution of the present invention is described in detail below through specific embodiments.

[0063] Example 1

[0064] This embodiment provides a gas generating agent, including a combustible (guanidine nitrate-26.9% and CuGUN (guanyl urea copper nitrate)-25.0%), a main oxidant (basic copper nitrate-45.2%), and a skeleton composition (MgO-2%, B4C-0.2%, KNO3-0.7%).

[0065] The method for making the gas generating agent of this embodiment includes:

[0066] 1) Take a certain amount of water and dissolve soluble nitrates such as potassium nitrate;

[0067] 2) Pour boron carbide into the above solution and stir evenly;

[0068] 3) adding other substances remaining in the gas generating agent to the above obtained mixed solution and adding a certain amount of alcohol to mix evenly and granulate;

[0069] 4) drying the obtained particles at 75°C in vacuum;

[0070] 5) Add a release agent to the particles and press them into tablets to obtain a gas generating agent.

[0071] Example 2

[0072] This embodiment provides a gas generating agent, including a combustible (guanidine nitrate-31.7% and CuGUN (guanyl urea copper nitrate)-20.0%), a main oxidant (basic copper nitrate-45.4%), and a skeleton composition (MgO-2%, B4C-0.2%, KNO3-0.7%).

[0073] The difference between Example 2 and Example 1 is that the proportions of the combustible agent and the oxidant are different. The preparation method of the gas generating agent in Example 2 is the same as that in Example 1.

[0074] Example 3

[0075] This embodiment provides a gas generating agent, including a combustible (guanidine nitrate-26.9% and CuGUN (guanyl urea copper nitrate)-25.0%), a main oxidant (basic copper nitrate-43.3%), and a skeleton composition (MgO-2%, B4C-0.6%, KNO3-2.2%).

[0076] The difference between Example 3 and Example 1 is that the proportions of the skeleton composition and the oxidant are different. The preparation method of the gas generating agent in Example 3 is the same as that in Example 1.

[0077] Example 4

[0078] This embodiment provides a gas generating agent, including a combustible (guanidine nitrate-30.1% and CuGUN (guanyl urea copper nitrate)-20.0%), a main oxidant (basic copper nitrate-45.1%), and a skeleton composition (MgO-2%, B4C-0.6%, KNO3-2.2%).

[0079] The difference between Example 4 and Example 1 is that the proportions of the combustible agent, the oxidant and the skeleton composition are different. The preparation method of the gas generating agent in Example 4 is the same as that in Example 1.

[0080] Example 5

[0081] The present embodiment provides a gas generating agent, including a combustible (guanidine nitrate-26.9% and CuGUN (guanyl urea copper nitrate)-25.0%), a main oxidant (basic copper nitrate-42.2%), an auxiliary oxidant (potassium perchlorate-3%), and a skeleton composition (MgO-2%, B4C-0.2%, KNO3-0.7%).

[0082] The difference between Example 5 and Example 1 is that an auxiliary oxidant is added, and the preparation method of the gas generating agent in Example 5 is the same as that in Example 1.

[0083] Example 6

[0084] This embodiment provides a gas generating agent, including a combustible (guanidine nitrate-26.9% and pentaaminotetrazole-25.0%), a main oxidant (basic copper nitrate-45.2%), and a skeleton composition (MgO-2%, B4C-0.2%, KNO3-0.7%).

[0085] The difference between Example 6 and Example 1 is that the type of combustible agent is different. The preparation method of the gas generating agent in Example 6 is the same as that in Example 1.

[0086] Comparative Example 1

[0087] This embodiment provides a gas generating agent, including 54% guanidine nitrate, 34% basic copper nitrate, 5% potassium nitrate, 3% ammonium perchlorate, and 3% aluminum oxide.

[0088] The gas generating agents obtained in the above Examples 1-6 and Comparative Example 1 were pressed into tablets with a diameter of 20 mm and a thickness of 6 to 10 mm, and dried to a moisture content of <0.4%, and the following were obtained: Figure 1 Tablets shown (Examples 1 to 4 and Comparative Example 1). Tablets were taken for combustion test and the results were as follows Figure 2 The combustion test results are shown.

[0089] in, Figure 2 The results of the combustion test show that Examples 1-4 are consistent with the combustion expectations, maintain a good overall block structure, and have a strong skeleton. However, after the combustion of Comparative Example 1, a fluffy residue structure can be seen, and many burned copper particles cannot be adsorbed.

[0090] In the description of the embodiments of the present invention, it should be noted that the orientation or positional relationship of terms such as "center", "up", "down", "left", "right", "vertical", "horizontal", "inside" and "outside" are based on the orientation or positional relationship described in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0091] What is disclosed above is only a preferred embodiment of the present invention, and it certainly cannot be used to limit the scope of rights of the present invention. Ordinary technicians in this field can understand that all or part of the processes of the above embodiment and equivalent changes made according to the claims of the present invention still fall within the scope covered by the present invention.

Claims

1. A gas generating agent, characterized in that: The invention comprises a combustible, an oxidant and a skeleton composition; the skeleton composition comprises a carbide and a combination of metal nitrates and / or metal oxides.

2. The gas generating agent according to claim 1, characterized in that: The carbide includes boron carbide and / or silicon carbide; the metal nitrate includes at least one of potassium nitrate, sodium nitrate and strontium nitrate; and the metal oxide includes at least one of magnesium oxide, aluminum oxide, calcium oxide, cobalt oxide and zirconium oxide.

3. The gas generating agent according to claim 1, characterized in that: The mass ratio of the carbide, the metal nitrate and the metal oxide satisfies the stoichiometric ratio of the chemical reaction equation of the three.

4. The gas generating agent according to claim 1, characterized in that: The combustible agent includes one or more combinations of nitroguanidine, guanidine nitrate, pentaaminotetrazole, guanyl urea copper nitrate and melamine.

5. The gas generating agent according to claim 1, characterized in that: The oxidant includes a main oxidant, and the main oxidant includes a combination of one or more of basic copper nitrate, copper oxide, iron oxide, and ammonium nitrate.

6. The gas generating agent according to claim 5, characterized in that The oxidant further comprises an auxiliary oxidant, the combustion speed of the auxiliary oxidant being greater than the combustion speed of the main oxidant.

7. The gas generating agent according to claim 6, characterized in that: The auxiliary oxidant includes potassium perchlorate, ammonium perchlorate or a combination of the two.

8. The gas generating agent according to claim 6 or 7, characterized in that: Calculated by mass percentage, the proportion of the main oxidant and the auxiliary oxidant in the gas generating agent is: 20% to 50% for the main oxidant and 1% to 10% for the auxiliary oxidant.

9. The gas generating agent according to claim 1, characterized in that: Calculated by mass percentage, the proportion of each component in the gas generating agent is: 30% to 60% of the combustible agent, 21% to 60% of the oxidant, and 0.1% to 10% of the skeleton composition.

10. A safety airbag, characterized in that: The safety airbag comprises an airbag body and a gas generating agent as described in any one of claims 1-9.

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