Gas generating agent and airbag

Abstract

A gas generating agent and an airbag. The gas generating agent comprises a combustible agent, an oxidant and a skeleton composition. The skeleton composition comprises a carbide, and a combination of a metal nitrate and / or a metal oxide.

Description

Gas generating agent and safety airbag

[0001] This application claims priority to the Chinese patent application No. 202410973975.6 filed on July 19, 2024 with the China Patent Office, the whole content of the above application is incorporated herein by reference. TECHNICAL FIELD

[0002] The present application relates to the technical field of automobile safety equipment, in particular to a gas generating agent and a safety airbag. BACKGROUND

[0003] With the improvement of people's living quality, the popularization of automobiles is more and more wide, and the safety problem of automobiles is increasingly concerned by consumers. As the core component of the automobile safety airbag, the type and performance requirements of the gas generating agent are also increasingly perfect. However, no matter what type of gas generating agent, it needs to meet the following requirements: safe and reliable, timely action; under high and low temperature environment, the related functions should meet the requirements of automobile safety airbag gas generator industry; the generated gas is basically non-toxic and non-corrosive, and harmless to passengers; the gas temperature is as low as possible to prevent fire or burn the personnel; meet the equipment and storage requirements; low residue rate, high gas production rate, etc. TECHNICAL PROBLEM

[0004] Because most of the gas generators will generate a large amount of residue after use, the residue is small in volume and difficult to filter, which will enter the airbag body through the filter screen, thereby causing harm to the human body. TECHNICAL SOLUTION

[0005] The present application provides a gas generating agent, which comprises a combustible agent, an oxidizing agent and a skeleton composition; the skeleton composition comprises a carbide, and a combination of a metal nitrate and / or a metal oxide.

[0006] The present application also provides a safety airbag, which comprises an airbag body and the aforementioned gas generating agent, and the gas generating agent is arranged in the airbag body. ADVANTAGEOUS EFFECTS

[0007] The gas generating agent provided by the present application utilizes the rapid combustion of the combustible agent and the oxidizing agent to emit a large amount of gas, thereby rapidly inflating the airbag. The skeleton composition in the gas generating agent can quickly form a whole block-shaped pyrotechnic skeleton after combustion. On the one hand, the whole block-shaped structure of the pyrotechnic skeleton can reduce the weight of the filter screen, or no filter screen is used, thereby replacing the filter screen in the related art, so as to reduce the manufacturing cost of the airbag. On the other hand, the pyrotechnic skeleton can also adsorb smaller combustion residues, so that the gas discharged into the airbag bag is cleaner. BRIEF DESCRIPTION OF DRAWINGS

[0008] Fig. 1 is an appearance view of the gas generating agent of the embodiment and the comparative example;

[0009] Figure 2 is a picture of the appearance of the gas generating agent after combustion of the embodiment and the comparative example. Embodiment of the present application

[0010] The present application provides a gas generating agent applied in a safety airbag. The gas generating agent comprises a combustible agent, an oxidizing agent, and a skeleton composition. The skeleton composition comprises a carbide and a combination of a metal nitrate and / or a metal oxide. The present application uses the rapid combustion of the combustible agent and the oxidizing agent to release a large amount of gas, so that the airbag is rapidly inflated. The skeleton composition in the gas generating agent rapidly forms a whole block-shaped pyrotechnic skeleton after combustion. On the one hand, the whole block-shaped structure of the pyrotechnic skeleton can reduce the weight of the filter screen, or the filter screen is not used, thereby reducing the manufacturing cost of the airbag. On the other hand, the pyrotechnic skeleton can also adsorb smaller combustion residues, so that the gas discharged into the airbag bag is cleaner.

[0011] In an embodiment, the carbide comprises boron carbide and / or silicon carbide; the metal nitrate comprises at least one of potassium nitrate, sodium nitrate, and strontium nitrate; and the metal oxide comprises at least one of magnesium oxide, aluminum oxide, calcium oxide, cobalt oxide, and zirconium oxide.

[0012] In a specific embodiment, the skeleton composition can comprise a carbide and a metal nitrate. The carbide can react with the metal nitrate to form a metal borate or a metal silicate. The metal borate or the metal silicate can form a molten glass body. The tiny particles generated by the combustion of the system are easily adsorbed by the molten glass body to form a network structure. After cooling after combustion, a whole glass pyrotechnic skeleton is formed.

[0013] In a specific embodiment, the skeleton composition can comprise a carbide and a metal oxide. The carbide can react with the metal oxide to form a glass body with a higher melting point. For example, the metal oxide is an alkaline earth metal oxide. The alkaline earth metal oxide can form a glass body with a higher melting point. The alkaline earth metal oxide can be a pure substance or a mixture. The high-melting-point oxide can keep the shape of the gas generating agent after combustion and maximize the adsorption of tiny particles.

[0014] In specific embodiments, the skeleton composition can include carbide, metal nitrate and metal oxide. In an oxygen atmosphere, the carbide can react with the metal nitrate and the metal oxide to obtain a glass body. The advantage of using the metal nitrate and the metal oxide to react with the carbide is that the product of the reaction between the carbide and the metal nitrate is also acidic, which can on the one hand dissolve part of the metal oxide to intensify the reaction process, and on the other hand catalyze the overall combustion efficiency of the gas generating agent, so that the gas generating agent reacts rapidly after starting to burn to form a stable pyrotechnic skeleton and generate a large amount of gas.

[0015] In other embodiments, hydroxides can also be used to replace the oxides in the gas generating agent, such as aluminum hydroxide, bismuth hydroxide, etc. The purpose of using hydroxides to compose the gas generating agent is the same as that of using metal oxides, and the stability of hydroxides is better than that of metal oxides because hydroxides are not easy to absorb water and deteriorate.

[0016] 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.

[0017] In specific embodiments, the carbide is boron carbide, and the metal nitrate is sodium nitrate. The reaction equation of boron carbide and sodium nitrate is as follows:

[0018] 2B4C + 4NaNO3 + 3O2 = 2Na2B4O7 + 2CO2 + 2N2

[0019] Among them, O2 is derived from the oxygen provided after the combustion of the gas generating agent system, B4C generates B2O3 after combustion in the system, and the acidic B2O3 and the oxide generated after the decomposition of alkali metals such as sodium nitrate form a tetraborate glass body (sodium tetraborate), and can generate a large amount of gas, and also serve to inflate the airbag. Thus, in the above chemical reaction equation system, the stoichiometric ratio of the carbide and the metal nitrate is 2:4.

[0020] In related technologies, tetraborate glass bodies are usually directly added to the gas generating agent to absorb residues, but the strong hygroscopicity of tetraborate glass bodies is not considered, which is difficult to implement, and in addition, part of the metal salt is also a harmful substance, which is a prohibited substance in the gas generating agent.

[0021] The application uses the raw materials of tetraborate glass bodies to generate glass bodies in situ under the high-temperature conditions of the combustion of gunpowder, and the hygroscopic substance is not generated before the combustion is completed, and the other substances (such as oxidants and combustibles) of the gas generating agent do not exist strong hygroscopic substances before ignition, avoiding the breakage of the tablet due to moisture, thereby avoiding the situation of rapid increase of the burning surface and the explosion of the chamber.

[0022] In specific embodiments, the carbide is boron carbide, and the metal oxide can include magnesium oxide, calcium oxide, aluminum oxide, cobalt oxide, zirconium oxide. Boron oxide is generated after the boron carbide burns in the system. The reaction equation of boron oxide and metal oxide is as follows:

[0023] B2O3+MgO=MgB2O4, 2B2O3+CaO=CaB4O7, B2O3+Al2O3=2AlBO3, B2O3+Co2O3=Co2B2O6

[0024] Alternatively, a mixture can also exist in a metering ratio, and the reaction equation is as follows:

[0025] 4B2O3+CaO+MgO+Al2O3=MgB2O4+CaB4O7+2AlBO3

[0026] The mass ratio is B2O3:CaO:MgO:Al2O3=59:12:8:21. Among them, different alkali metal nitrate or alkaline earth metal oxide plays different roles in the combustion reaction of the gas generating agent, for example, when the content of B2O3 is relatively high, the slag forming property is better, the overall smoke fire skeleton is more complete, and the adsorption performance is better, if MgO is added, not only the profile can be maintained, but also the burning rate of the combustion system can be improved, especially after the addition of BaO, ZrO2, etc., the catalytic effect on the combustion system is obviously promoted.

[0027] In one embodiment, the combustible agent includes one or more combinations of nitroguanidine, guanidine nitrate, pentaamino tetrazole, amidine urea, copper nitrate, and melamine. The above materials are all explosive materials, and through the reaction of the combustible agent with the oxidizing agent and the skeleton composition, a large amount of gas can be generated instantaneously, so that the airbag is inflated.

[0028] In one embodiment, the oxidizing agent includes a main oxidizing agent, and the main oxidizing agent includes one or more combinations of basic copper nitrate, copper oxide, iron oxide, and ammonium nitrate.

[0029] In one embodiment, the oxidizing agent further includes an auxiliary oxidizing agent, and the combustion speed of the auxiliary oxidizing agent is greater than that of the main oxidizing agent. The addition of the auxiliary oxidizing agent with improved burning rate can improve the burning rate of the system.

[0030] It should be explained that the burning speed reflects the amount (mass or volume) of the auxiliary oxidizer and the primary oxidizer burned per unit time. In specific embodiments, the method for testing the burning speed of the auxiliary oxidizer and the primary oxidizer can be that, under the same environmental conditions, a gas generating agent with only the primary oxidizer and a gas generating agent with only the auxiliary oxidizer are taken as test objects, and both of the gas generating agents are in the shape of a circular disc. The two pieces of the gas generating agent are ignited at the same time, and the diameter D1 of the gas generating agent before ignition and the diameter D2 of the gas generating agent after ignition and complete combustion are recorded, the burning time is T, and the burning speed is V=(D1-D2) / T.

[0031] In an embodiment, the auxiliary oxidizer comprises one or a combination of potassium perchlorate and ammonium perchlorate.

[0032] In specific embodiments, the gas generating agent can comprise boron carbide, basic copper nitrate, nitroguanidine and potassium nitrate, and the reaction equation is as follows:

[0033] 0.6B4C+46.3Cu4N2H6O 12 +50.9CH6N4O3+2.2KNO3→2.5K2B4O7+24.6Cu+26.6N2+18.7CO2+27.6H2O

[0034] The potassium tetraborate glass body formed in the reaction equation adsorbs the generated Cu particles, thereby achieving the effect of filtration and adsorption. If BaO and ZrO2 are further added, a solid glass and copper residue is formed, and the residue is in the form of an integral block.

[0035] In an embodiment, the primary oxidizer and the auxiliary oxidizer in the gas generating agent account for 20% to 50% and 1% to 10% by mass percentage. Optionally, the primary oxidizer in the gas generating agent can account for 20%, 25%, 30%, 35%, 40%, 45% or 50%. Optionally, the auxiliary oxidizer in the gas generating agent can account for 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%.

[0036] The primary oxidizer and the auxiliary oxidizer are within the above range, so as to ensure that the primary oxidizer and the auxiliary oxidizer can play a synergistic role, so as to increase the burning speed of the gas generating agent, and to avoid flash explosion caused by too fast burning. When the primary oxidizer and the auxiliary oxidizer are less than the above range, the content of the oxidizer mainly used for initiation in the gas generating agent is reduced, the burning speed of the gas generating agent is reduced, and the gas generating agent cannot quickly generate gas when the safety airbag is in action. When the primary oxidizer and the auxiliary oxidizer are greater than the above range, the proportion of the gas substance in the gas generating agent is reduced, and the skeleton composition is difficult to be formed, and too fast burning can cause safety hazards.

[0037] In one embodiment, the proportions of the components in the gas generating agent, by mass percentage, are: combustible agent 30% to 60%, oxidizing agent 21% to 60%, and framework composition 0.1% to 10%. Optionally, the proportion of the combustible agent in the gas generating agent can be 30%, 35%, 40%, 45%, 50%, 55%, or 60%. Optionally, the proportion of the oxidizing agent in the gas generating agent can be 21%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, or 60%. Optionally, the proportion of the framework composition in the gas generating agent can be 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10%.

[0038] Satisfying the mass proportions of the combustible agent, the oxidizing agent, and the framework composition within the above ranges can ensure that the gas generating agent burns rapidly to generate gas and forms an overall block-shaped pyrotechnic framework, and can also ensure safety during combustion. When the proportion of the framework composition is less than the above range, it is difficult to form an overall block-shaped pyrotechnic framework, and the proportions of the combustible agent and the oxidizing agent are too large, and too rapid combustion can cause safety hazards. When the proportion of the framework composition is greater than the above range, the combustion speed of the gas generating agent decreases, and gas cannot be generated rapidly when the safety airbag is in action.

[0039] In one embodiment, the application also provides a method for manufacturing a gas generating agent, comprising:

[0040] In step S10, the combustible agent, the oxidizing agent, and the framework composition are mixed to obtain a mixture.

[0041] In step S20, the mixture is made into mixed particles, and the gas generating agent is obtained after drying and pressing.

[0042] The framework composition includes a carbide, and a combination of a metal nitrate and / or a metal oxide.

[0043] Optionally, in step S10, the mixture is obtained by mixing the combustible agent, the oxidizing agent, and the framework composition, including: 1) dissolving the metal nitrate in a solvent and fully dissolving; 2) adding the carbide to the above solvent and stirring uniformly; and 3) adding the combustible agent, the oxidizing agent, and the optional metal oxide to the above solvent to obtain the mixture.

[0044] Optionally, in step S20, the mixture is made into mixed particles, and the gas generating agent is obtained after drying and pressing, including: 4) adding alcohol to the mixture, mixing uniformly, and granulating; 5) drying the obtained particles in a vacuum at 70°C to 80°C; and 6) adding a release agent to the dried particles and tabletting to form the gas generating agent.

[0045] Optionally, the proportions of the components in the gas generating agent can refer to the above embodiments, combustible agent 30% to 60%, oxidizing agent 21% to 60%, and skeleton composition 0.1% to 10%.

[0046] Optionally, the granulation can be performed by a granulator, and after the granulation, the particles are filtered through a 20-mesh screen, the undersize is collected and placed in a vacuum oven to dry until the volatile matter is less than 0.4%.

[0047] Optionally, the gas generating agent obtained by tabletting by a tablet machine is a tablet with a diameter of 6 mm and a thickness of 1.8 mm.

[0048] In one embodiment, the application further provides a safety air bag, which comprises an air bag body and the gas generating agent provided by the above embodiments.

[0049] The technical solutions of the application are described in detail below through specific embodiments.

[0050] Example 1

[0051] The embodiment provides a gas generating agent, which comprises a combustible agent (guanidine nitrate-26.9% and CuGUN (cupric ammidinate nitrate)-25.0%), a main oxidizing agent (basic copper nitrate-45.2%), and a skeleton composition (MgO-2%, B4C-0.2%, KNO3-0.7%).

[0052] The manufacturing method of the gas generating agent in the embodiment comprises:

[0053] 1) A certain amount of water is taken, and an easily soluble nitrate salt such as potassium nitrate is dissolved;

[0054] 2) Boron carbide is poured into the above solution and stirred uniformly;

[0055] 3) The remaining other substances in the gas generating agent are added to the obtained mixture, and a certain amount of alcohol is added to mix uniformly and granulate;

[0056] 4) The obtained particles are vacuum dried at 75°C;

[0057] 5) The particles are tabletted after adding a release agent to obtain the gas generating agent.

[0058] Example 2

[0059] The embodiment provides a gas generating agent, which comprises a combustible agent (guanidine nitrate-26.9% and CuGUN (cupric ammidinate nitrate)-25.0%), a main oxidizing agent (basic copper nitrate-45.2%), and a skeleton composition (MgO-2%, B4C-0.2%, KNO3-0.7%).

[0060] The difference between Example 2 and Example 1 is that the proportions of the combustible agent and the oxidizing agent are different, and the production method of the gas generating agent of Example 2 is the same as that of Example 1.

[0061] Example 3

[0062] The present example provides a gas generating agent, which comprises a combustible agent (guanidine nitrate-26.9% and CuGUN (Cu (guanylurea nitrate))-25.0%), a main oxidizing agent (basic copper nitrate-43.3%), and a skeleton composition (MgO-2%, B4C-0.6%, KNO3-2.2%).

[0063] The difference between Example 3 and Example 1 is that the proportions of the skeleton composition and the oxidizing agent are different, and the production method of the gas generating agent of Example 3 is the same as that of Example 1.

[0064] Example 4

[0065] The present example provides a gas generating agent, which comprises a combustible agent (guanidine nitrate-30.1% and CuGUN (Cu (guanylurea nitrate))-20.0%), a main oxidizing agent (basic copper nitrate-45.1%), and a skeleton composition (MgO-2%, B4C-0.6%, KNO3-2.2%).

[0066] The difference between Example 4 and Example 1 is that the proportions of the combustible agent, the oxidizing agent, and the skeleton composition are different, and the production method of the gas generating agent of Example 4 is the same as that of Example 1.

[0067] Example 5

[0068] The present example provides a gas generating agent, which comprises a combustible agent (guanidine nitrate-26.9% and CuGUN (Cu (guanylurea nitrate))-25.0%), a main oxidizing agent (basic copper nitrate-42.2%), an auxiliary oxidizing agent (potassium perchlorate-3%), and a skeleton composition (MgO-2%, B4C-0.2%, KNO3-0.7%).

[0069] The difference between Example 5 and Example 1 is that an auxiliary oxidizing agent is added, and the production method of the gas generating agent of Example 5 is the same as that of Example 1.

[0070] Example 6

[0071] The present example provides a gas generating agent, which comprises a combustible agent (guanidine nitrate-26.9% and CuGUN (Cu (guanylurea nitrate))-25.0%), a main oxidizing agent (basic copper nitrate-42.2%), an auxiliary oxidizing agent (potassium perchlorate-3%), and a skeleton composition (MgO-2%, B4C-0.2%, KNO3-0.7%).

[0072] The difference between Example 6 and Example 1 is that the type of the combustible agent is different, and the production method of the gas generating agent of Example 6 is the same as that of Example 1.

[0073] Comparative Example 1

[0074] The present example provides a gas generating agent comprising 54% guanidine nitrate, 34% basic copper nitrate, 5% potassium nitrate, 3% ammonium perchlorate, 3% aluminum oxide, and 1% zinc stearate.

[0075] The gas generating agents obtained in the above Examples 1-6 and Comparative Example 1 were compressed into tablets having a diameter of 20 mm and a thickness of 6-10 mm, dried to a moisture content of <0.4%, and tablets were obtained as shown in Figure 1 (Examples 1-4 and Comparative Example 1). The tablets were subjected to combustion tests, and the results are shown in Figure 2.

[0076] In Figure 2, the combustion test results show that Examples 1-4 are consistent with the expected combustion, maintaining the overall bulk structure and a relatively strong skeleton. In contrast, the residue structure of Comparative Example 1 is fluffy after combustion, and many of the burned copper particles are not adsorbed.

Claims

1. A gas generating agent, comprising a combustible agent, an oxidizing agent, a skeleton composition; the skeleton composition comprises a carbide, and a combination of a metal nitrate and / or a metal oxide.

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

3. The gas generating agent according to claim 1 or 2, wherein 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 generant of any one of claims 1 to 3, wherein, The combustible agent comprises a combination of one or more of nitroguanidine, guanidine nitrate, pentaamino tetrazole, amidino urea, copper nitrate, and melamine.

5. The gas generant of any one of claims 1 to 4, wherein, The oxidizing agent comprises a main oxidizing agent, the main oxidizing agent comprises 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, wherein The oxidizing agent further comprises an auxiliary oxidizing agent, the combustion speed of the auxiliary oxidizing agent is greater than that of the main oxidizing agent.

7. The gas generating agent according to claim 6, wherein The auxiliary oxidizing agent comprises a combination of one or both of potassium perchlorate and ammonium perchlorate.

8. The gas generating agent according to claim 6 or 7, wherein In the gas generating agent, the proportion of the main oxidizing agent and the auxiliary oxidizing agent is 20%-50% for the main oxidizing agent and 1%-10% for the auxiliary oxidizing agent, in terms of mass percentage.

9. The gas generant of any one of claims 1 to 8 wherein, In the gas generating agent, the proportion of each component is 30%-60% for the combustible agent, 21%-60% for the oxidizing agent, and 0.1%-10% for the skeleton composition, in terms of mass percentage. 10.A safety airbag, comprising an airbag body and the gas generating agent according to any one of claims 1 to 9.

Images