A TNBA cast explosive and a preparation method thereof

Abstract

The application provides a TNBA cast explosive and a preparation method thereof, and belongs to the technical field of cast explosive preparation. The TNBA cast explosive is prepared according to the mass percentage of 50.6-55.2% of a liquid carrier, 4.4-4.8% of a fluxing agent and 40-45% of a solid filler. The TNBA cast explosive prepared by the application has the following advantages: the liquid carrier and the fluxing agent have high density, low volatility, low toxicity, low sensitivity and good formability, and no shrinkage hole and crack after pouring; the solid filler has the characteristics of high energy, low sensitivity, high density and high explosion heat; the raw material cost is low, the preparation process is simple, and the explosive can be produced on a large scale; compared with the existing explosives, the cast explosive has high oxygen balance, can generate more heat, has high density, detonation velocity, explosion heat and explosion pressure, and low impact sensitivity, and has higher performance than ordinary explosives.

Description

Technical Field

[0001] This invention relates to the field of molten cast explosives preparation technology, and in particular to a TNBA molten cast explosive and its preparation method. Background Technology

[0002] Existing cast explosives primarily use TNT as a carrier. However, cast explosives using TNT as a carrier are costly to prepare and suffer from problems such as low density, toxicity, high saturated vapor pressure, and high sensitivity during use, failing to meet the requirements of modern insensitive munitions (IM). Therefore, finding a liquid-phase cast carrier to replace TNT is an urgent problem to be solved.

[0003] 3-Bromo-2,4,6-trinitroanisole (TNBA) is a novel carrier explosive synthesized in recent years, with a density as high as 1.948 g / cm³. -3 TNBA has a detonation velocity close to that of TNT (6571 m / s), but a detonation pressure much higher, reaching 24 GPa. Its saturated vapor pressure in the liquid state is 1 / 30th that of TNT, and its toxicity is far less than that of TNT during production and application. Because TNBA is less sensitive than TNT and has a higher energy level than 2,4-dinitroanisole (DNAN), its production cost is relatively low, and it is environmentally friendly. It has been included in BAE Systems' GrIMEx and IRAD projects as one of the alternatives to TNT-based cast explosive carriers. In 2018, the U.S. Army Ammunition Plant Holston (HSAAP) reported the evaluation results of TNBA-based cast explosives, showing that they outperformed existing TNT-based IM explosives (IMX-104 / PAX-48), but their formulation remains a secret.

[0004] However, TNBA has a melting point of 103℃, making it impossible to melt and cast using existing processes. Therefore, adding a small amount of casting explosive with a lower melting point to TNBA is an effective way to solve this problem. 3-Bromo-5-fluoro-2,4,6-trinitroanisole is a high-performance energetic compound with a melting point of 90℃, good thermal stability, and a high density of 2.073 g / cm³. 3 Its detonation velocity is close to that of TNT (6554 m / s), its sensitivity is lower than that of TNT, and its saturated vapor pressure and toxicity are much lower than those of TNT. It also exhibits good compatibility with TNBA. Our research group has experimentally demonstrated that adding a small amount of 3-bromo-5-fluoro-2,4,6-trinitroanisole to TNBA (≤10 wt.%) lowers the melting point of TNBA to below 90°C, meeting the requirements of current casting explosive preparation processes. Furthermore, it does not reduce the density of the carrier explosive, nor does it increase the saturated vapor pressure or toxicity of TNBA. Therefore, 3-bromo-5-fluoro-2,4,6-trinitroanisole is a good high-density flux for TNBA.

[0005] In addition, the chemical formula of the molecular perovskite energetic material DAP-4 is (C6H 14 N2)[NH4(ClO4)3], with a molecular weight of 430.6 g / mol and a density of 1.87 g / cm³. 3 Oxygen balance is OB CO2 = -27.9%, enthalpy of formation is +278.6 kJ / mol. Its theoretical detonation velocity reaches 8597 m / s, similar to RDX. The theoretical detonation heat and pressure of DAP-4 are -6879 kJ / kg and 35.6 GPa, respectively, which are among the highest of the known elemental energetic materials. DAP-4 has low sensitivity, with an impact sensitivity of H. 50 =112.3cm (2kg drop weight), friction sensitivity P=45% (2kg pendulum, 90° pendulum angle, 3.50MPa pressure), electrostatic sensitivity 5.39J. DAP-4 is also an excellent heat-resistant energetic material, with a thermal decomposition initiation temperature of 374℃ and a decomposition peak temperature of 401℃ (10℃ / min), and it is non-hygroscopic. Furthermore, DAP-4 exhibits excellent chemical compatibility with TNBA and 3-bromo-5-fluoro-2,4,6-trinitroanisole. Reported research results indicate that DAP-4 is an excellent elemental explosive, a heat-resistant explosive with higher energy than TATB. Currently, no literature or patents have described the use of DAP-4 in cast explosives. This patent discloses several mixed explosives using TNBA / 3-bromo-5-fluoro-2,4,6-trinitroanisole as a molten carrier and DAP-4 as a solid filler, and demonstrates their energy performance. Summary of the Invention

[0006] The purpose of this invention is to provide a TNBA fused cast explosive and its preparation method to solve the problems of low density, high volatility, high toxicity, and high sensitivity of existing TNT-based fused cast explosives.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0008] This invention provides a TNBA castable explosive comprising the following raw materials by weight percentage:

[0009] Liquid carrier: 50.6–55.2%;

[0010] Flux: 4.4–4.8%;

[0011] Solid filler: 40-45%, the sum of the mass percentages of all components is 100%.

[0012] Furthermore, the liquid carrier is TNBA, the flux is 3-bromo-5-fluoro-2,4,6-trinitroanisole, and the solid filler is DAP-4.

[0013] The present invention also provides a method for preparing the above-mentioned cast explosive, comprising the following steps:

[0014] The liquid carrier and flux are mixed, heated and stirred until completely dissolved into a liquid state. Solid filler is added and stirred to obtain a paste-like explosive. The paste-like explosive is poured into a mold and cooled to obtain TNBA cast explosive.

[0015] Furthermore, the air humidity when the liquid carrier and flux are mixed is less than 20H2O / kg.

[0016] Furthermore, the temperature at which the liquid carrier and flux are mixed and heated is 94–97°C.

[0017] Furthermore, the solid filler is stirred for 8 to 15 minutes until a uniform, flowable paste is formed.

[0018] Furthermore, the mold needs to be preheated to 60-70°C.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] (1) The liquid carrier and flux used in this invention have high density, low volatility, low toxicity, low sensitivity, and good formability, and no shrinkage cavities or cracks after casting.

[0021] (2) The solid filler used in this invention has the characteristics of high energy, low sensitivity, high density, and especially high heat of explosion.

[0022] (3) The raw materials involved in this invention are low in cost, the preparation process is simple, and there is a basis for large-scale production.

[0023] (4) Compared with existing explosives, the TNBA / 3-bromo-5-fluoro-2,4,6-trinitroanisole / DAP-4 cast explosive provided by the present invention has a high oxygen balance and can generate more heat; it has high density, detonation velocity, detonation heat and detonation pressure, and low impact sensitivity, and has higher performance than ordinary explosives. Attached Figure Description

[0024] Figure 1 This is a molecular structure diagram of DAP-4, a perovskite energetic material from Example 1. Detailed Implementation

[0025] In this invention, TNBA is 3-bromo-2,4,6-trinitroanisole, with the structure shown in Formula 1:

[0026]

[0027] In this invention, the structure of 3-bromo-5-fluoro-2,4,6-trinitroanisole is shown in Formula 2:

[0028]

[0029] In this invention, the synthetic route of 3-bromo-5-fluoro-2,4,6-trinitroanisole is as follows:

[0030]

[0031] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0032] Example 1

[0033] Preparation of TNBA melt-cast explosive:

[0034] (1) Preparation of 3-bromo-5-fluoro-2,4,6-trinitroanisole:

[0035] Mixed acid: Place a 100ml beaker in ice water, add 6mL of 80% concentrated nitric acid to the beaker, and slowly add 6mL of 95% concentrated sulfuric acid while stirring with a glass rod. Continue stirring and add 8mL of 20% fuming sulfuric acid. After mixing well, seal the beaker with plastic wrap and cool it to 5℃ in ice water.

[0036] Nitration: 2 g of 3-bromo-5-fluoroanisole was added to a three-necked flask containing the above mixed acid, heated in a water bath at 60°C, and stirred at 500 rpm for 1 h. After the reaction was complete, the mixture was washed with water, filtered, and dried to obtain approximately 3.0 g of product.

[0037] (2) Accurately weigh each raw material according to the formula in Table 1. In dry air with a humidity of less than 20 H2O / kg, preheat the melting kettle to 97℃ and the oven to 65℃. Then, weigh 5.52 g of TNBA and 0.48 g of 3-bromo-5-fluoro-2,4,6-trinitroanisole and add them to the melting kettle preheated to 97℃. Stir with a wooden stick until TNBA and 3-bromo-5-fluoro-2,4,6-trinitroanisole are completely dissolved into a liquid state. Then, add 4 g of DAP-4 to the melting kettle. Use a wooden stick to evenly disperse DAP-4 in the liquid carrier to form a uniform, flowable paste. After applying a release agent to the mold, place it in an oven preheated to 65℃ and then pour the paste explosive into the mold. Allow it to cool and solidify naturally at room temperature to obtain TNBA cast explosive.

[0038] Table 1. Formulation of cast explosive in Example 1

[0039]

[0040] Example 2

[0041] Preparation of TNBA cast explosive: Accurately weigh TNBA, DAP-4, and 3-bromo-5-fluoro-2,4,6-trinitroanisole prepared in Example 1 according to the formula in Table 2. Preheat the melting vessel to 97°C and the oven to 65°C in dry air with a humidity of less than 20 H2O / kg. Then, weigh 5.06 g of TNBA and 0.44 g of 3-bromo-5-fluoro-2,4,6-trinitroanisole and add them to the preheated melting vessel at 97°C. Stir with a wooden stick until TNBA and 3-bromo-5-fluoro-2,4,6-trinitroanisole are completely dissolved into a liquid state. Then, add 4.5 g of DAP-4 to the melting vessel. Disperse DAP-4 evenly in the liquid carrier with a wooden stick to form a uniform, flowable paste. After applying a release agent to the mold, place it in an oven and preheat it to 65°C. Then, pour the paste-like explosive into the mold and allow it to cool and solidify naturally at room temperature to obtain TNBA cast explosive.

[0042] Table 2 Formulation of Cast Explosive in Example 2

[0043]

[0044]

[0045] Comparative Example 1

[0046] Preparation of Classic B Explosive: Accurately weigh each raw material according to the formula in Table 3. In dry air with humidity less than 20 H2O / kg, preheat the melting kettle to 97℃ and the oven to 65℃. Then, weigh 6 grams of TNT and add it to the preheated melting kettle at 97℃, stirring with a wooden stick until the TNT is completely dissolved into a liquid state. Next, add 4 grams of RDX to the melting kettle. Disperse the RDX evenly in the liquid carrier with a wooden stick to form a uniform, flowable paste. After applying a release agent to the mold, preheat it in an oven to 65℃, then remove it and pour the paste explosive into the mold. Allow it to cool and solidify naturally at room temperature to obtain the cast explosive product of Comparative Example 1.

[0047] Table 3 shows the formulation of cast explosive in Comparative Example 1.

[0048]

[0049] Comparative Example 2

[0050] Preparation of Classic B Explosive: Accurately weigh each raw material according to the formula in Table 4. In dry air with humidity less than 20 H2O / kg, preheat the melting kettle to 97℃ and the oven to 65℃. Then, weigh 5.5g of TNT and add it to the preheated melting kettle at 97℃, stirring with a wooden stick until the TNT is completely dissolved into a liquid state. Next, add 4.5g of RDX to the melting kettle. Disperse the RDX evenly in the liquid carrier with a wooden stick to form a uniform, flowable paste. After applying a release agent to the mold, preheat it in an oven to 65℃, then pour the paste explosive into the mold. Allow it to cool and solidify naturally at room temperature to obtain the cast explosive product of Comparative Example 2.

[0051] Table 4. Formulation of cast explosive in Comparative Example 2

[0052]

[0053] Example 3

[0054] The performance of the cast explosives prepared in Examples 1-2 and Comparative Examples 1-2 was measured, and the results are shown in Table 5.

[0055] Table 5 shows the performance of cast explosives in Examples 1-2 and Comparative Examples 1-2.

[0056]

[0057] As shown in Table 5, the oxygen balance of the cast explosive prepared in Example 1 was -36.1%, significantly higher than that of the cast explosive prepared in Comparative Example 1. This is beneficial for generating more heat during the detonation process. The density of Example 1 was significantly higher than that of Comparative Example 1; the detonation velocity, heat of explosion, and detonation pressure of Example 1 were all slightly higher than those of Comparative Example 1. Impact sensitivity H 50 The higher the value, the less sensitive the explosive is. The impact sensitivity of Example 1 is significantly lower than that of Comparative Example 1, while the friction sensitivity of Example 1 is slightly higher than that of Comparative Example 1. The data in Table 5 show that, except for friction sensitivity, the cast explosive prepared in Example 1 has higher performance than ordinary B explosive.

[0058] The oxygen balance of the cast explosive prepared in Example 2 was -35.5%, significantly higher than that of the cast explosive prepared in Comparative Example 2, which is beneficial for generating more heat during the detonation process. The density of Example 2 was significantly higher than that of Comparative Example 2. The detonation velocity, heat of explosion, and detonation pressure of Example 2 were all slightly higher than those of Comparative Example 2. Impact sensitivity H... 50 The higher the value, the less sensitive the explosive is. The impact sensitivity of Example 2 is significantly lower than that of Comparative Example 2, while the friction sensitivity of Example 2 is slightly higher than that of Comparative Example 2. The data in Table 5 indicate that, except for friction sensitivity, the cast explosive prepared in Example 2 has higher performance than ordinary B explosive.

[0059] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A TNBA cast explosive, characterized in that, Including the following percentages of raw materials by weight: Liquid carrier: 50.6–55.2%; Flux: 4.4–4.8%; Solid filler: 40-45%, the sum of the mass percentages of all raw materials is 100%; The liquid carrier is TNBA, the flux is 3-bromo-5-fluoro-2,4,6-trinitroanisole, and the solid filler is DAP-4.

2. A method for preparing the cast explosive according to claim 1, characterized in that, Includes the following steps: The liquid carrier and flux are mixed, heated and stirred until completely dissolved into a liquid state. Solid filler is added and stirred to obtain a paste-like explosive. The paste-like explosive is poured into a mold and cooled to obtain TNBA cast explosive.

3. The preparation method according to claim 2, characterized in that, The air humidity when the liquid carrier and flux are mixed is less than 20H2O / kg.

4. The preparation method according to claim 3, characterized in that, The temperature at which the liquid carrier and flux are mixed and heated is 94–97°C.

5. The preparation method according to claim 2, characterized in that, The solid filler is stirred for 8 to 15 minutes until a uniform, flowable paste is formed.

6. The preparation method according to claim 2, characterized in that, The mold also needs to be preheated to 60-70°C.

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