High-explosion-heat insensitive environment-friendly firework propellant powder and preparation method thereof

Abstract

The invention discloses a high-explosion-heat insensitive environment-friendly firework propellant and a preparation method thereof, and belongs to the technical field of fireworks and crackers. Based on a thermal radiation principle, superfine metal powder with a high combustion heat value is selected as a combustible agent, high-molecular fluoride is used as an oxidizing agent, and a high-energy insensitive energetic material 3-nitro-1, 2, 4-triazole-5-ketone (NTO) is introduced to obtain the firework propellant. Wherein the high-molecular fluoride and the superfine active metal powder have good reactivity, and flame generated by the high-molecular fluoride and the superfine active metal powder contains solid and liquid scorching particle emitters, so that the flame is brighter in the combustion process of the fireworks and crackers; and by adding the high-energy insensitive energetic material NTO, the explosion heat and the throwing height of the firework propellant powder are improved. Compared with a traditional firework propellant formula, the obtained product has the advantages of being non-toxic, harmless, safe and environmentally friendly, and has good application value in the field of fireworks and crackers.

Description

Technical Field

[0001] The invention relates to a high-explosive heat-insensitive environment-friendly firework propellant and a preparation method thereof, belonging to the technical field of fireworks and firecrackers. Background Art

[0002] The innovation and development of fireworks and firecrackers are mainly attributed to the invention of black powder. Black powder has high mechanical sensitivity, flame sensitivity and electrostatic spark sensitivity. It may explode when it is subjected to strong impact or friction, encounters open flames, or encounters electrostatic sparks caused by dry weather. Therefore, black powder is dangerous in the process of production, storage, transportation and use, which is easy to cause safety accidents and unexpected disasters.

[0003] Fluoropolymers, as one of the representative products of special polymers, are widely used due to their good physical and chemical stability, low surface energy and excellent mechanical properties. Metal-fluoropolymer active materials, as a typical metal-oxide system, can react and release a large amount of chemical energy under heating or high-speed impact conditions. Fluoropolymers will release fluorine elements with strong oxidizing properties under high temperature conditions, increase the reactivity of metal powders, and activate metal powders to deflagrate, thereby generating overpressure and thermal effects. However, the use of metal-fluoropolymer systems as fireworks propellants has the disadvantages of poor ignition performance, explosive heat and insufficient range extension, which seriously affects the viewing quality of fireworks. Introducing high-energy insensitive energetic materials into metal-oxide systems to obtain non-toxic, harmless and environmentally friendly fireworks propellant products through premixing and granulation is a technical problem that needs to be solved urgently by technicians in this field, and there is no public report yet. Summary of the invention

[0004] The invention relates to a high-explosion heat-insensitive environmentally friendly fireworks propellant and a preparation method thereof. Active metal powder is used as a combustible agent, polymer fluoride is used as an oxidant, a PVA-modified high-energy-insensitive NTO (3-nitro-1,2,4-triazole-5-one) composite energetic material is introduced, and a flammable polymer polyurethane slurry is synthesized as an adhesive. A fireworks propellant product is obtained by extrusion granulation, thereby improving the explosion heat, throwing height and ignition performance of the fireworks propellant.

[0005] The present invention is achieved through the following technical solutions.

[0006] A high-explosive heat-insensitive environmentally friendly fireworks propellant is composed of a basic formula of fluoropolymer-based safe and environmentally friendly fireworks propellant and a high-energy insensitive energetic material NTO.

[0007] The preparation method of the high-explosive heat-insensitive environmentally friendly fireworks propellant comprises the following steps:

[0008] (1) drying magnesium powder, aluminum powder and boron powder at 60-80° C. and transferring them into a V-type mixer, adding manganese dioxide, a fireworks range extender, and mixing for 1-2 hours to obtain an active metal powder mixture;

[0009] (2) adding silane coupling agent KH550 to polytetrafluoroethylene powder, mixing them evenly in a mixer, and drying them at 80-100° C. to obtain modified polytetrafluoroethylene;

[0010] (3) dispersing the active metal powder obtained in step (1), the modified polytetrafluoroethylene powder obtained in step (2), and the NTO energetic composite material in polyether polyol, and slowly adding diisocyanate to obtain a mixed slurry with polyurethane as an adhesive;

[0011] (4) The mixed slurry obtained in step (3) is extruded and granulated through a granulator with a 2 mm granular plate, and dried at 60 to 80° C. to obtain a high-explosive heat-insensitive environmentally friendly fireworks propellant.

[0012] Preferably, the formula of the fireworks propellant is as follows, in terms of mass parts: 5-10 parts of magnesium powder, 15-25 parts of aluminum powder, 2-5 parts of boron powder, 5-8 parts of manganese dioxide; 20-35 parts of polytetrafluoroethylene, 1-2 parts of silane coupling agent, 5-15 parts of NTO energetic composite material; and 5-15 parts of polyurethane adhesive.

[0013] Preferably, the functional group ratio of the polyether polyol to the diisocyanate is 1:1, and the diisocyanate is one or more combinations of toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate (HDI), and isophorone diisocyanate (IPDI).

[0014] The preparation process of the NTO energetic composite material comprises the following steps:

[0015] (1) dissolving the energetic material NTO in anhydrous ethanol at 60-80° C. to obtain a transparent solution;

[0016] (2) dissolving polyvinyl alcohol (PVA) in deionized water at 80-90° C. to obtain a transparent solution;

[0017] (3) The PVA aqueous solution obtained in step (2) is slowly added to the NTO solution obtained in step (1) under an ultrasonic environment, and mechanically stirred at 80 to 90° C. for 2 to 3 hours to make the mixture uniformly mixed, and then ultrasonicated at 100° C. and a solvent evaporation method is used to obtain a PVA-modified NTO composite energetic material.

[0018] Preferably, the mass ratio of NTO to PVA in the NTO energetic composite material is 10-15.

[0019] Compared with the basic formula of fluoropolymer-based propellant, the high-explosion heat-insensitive environment-friendly fireworks propellant obtained by the present invention has an explosion heat increased by more than 30% and a throwing height increased by more than 20%.

[0020] The invention has the following beneficial effects:

[0021] (1) The present invention uses a silane coupling agent to modify polytetrafluoroethylene, and synthesizes a polyurethane slurry as an adhesive for fireworks propellants to improve the interfacial adhesion and ignition performance of the propellant. There are a large number of stable CF bonds in fluoropolymers, and the F atom has a strong shielding effect on the CC main chain, which makes the fluoropolymer extremely chemically inert, resulting in poor ignition performance of the metal-fluoropolymer system. In addition, the fluoropolymer lacks groups with strong bonding properties, so the interfacial adhesion performance of the fluoropolymer is limited. The present invention synthesizes a flammable polymer polyurethane, which is used as an adhesive and a metal-fluoropolymer system through extrusion granulation to obtain a fireworks propellant product. The polyurethane is very easy to ignite, which promotes the reaction of the metal-fluoropolymer system. Then, the silane coupling agent KH550 is used to modify polytetrafluoroethylene, which improves the interfacial adhesion between polytetrafluoroethylene and active metal powder and accelerates the reaction rate of the propellant system.

[0022] (2) The present invention uses water-soluble polymer PVA to modify the energetic material NTO, which not only improves the acidity of NTO and reduces its sensitivity, but also improves the adhesion between NTO and the fireworks propellant system. The nitro and carbonyl groups in the molecular structure of NTO have a strong electron-withdrawing effect, which reduces the electron cloud density of its adjacent nitrogen atoms, making hydrogen easily ionized, so that NTO exhibits strong acidity, which is not conducive to the use and storage of fireworks propellants. As a water-soluble polymer, PVA has abundant hydroxyl groups between / in its molecules, which form hydrogen bonds with -NH- in NTO molecules, inhibit the ionization of hydrogen, and improve the acidity of NTO. PVA polymer has good adhesion. Introducing it into NTO can not only promote the adhesion between NTO molecules, but also improve the adhesion between NTO and the basic formula system of fireworks propellants, which is conducive to improving its processing technology. In addition, compounding the high molecular polymer PVA with NTO can reduce the sensitivity of NTO and further improve the safety of the use, storage and transportation of fireworks propellants.

[0023] (3) The present invention combines high-energy insensitive NTO energetic materials, range extender manganese dioxide and active metal-polytetrafluoroethylene. The resulting product has both the high energy and high explosion heat characteristics of NTO and the insensitivity and high safety characteristics of active metal-polytetrafluoroethylene. With the help of the range extender manganese dioxide, the explosion heat of the fireworks propellant is increased by more than 30% and the throw height is increased by more than 20%. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1This is a scanning electron microscope image of the PVA-modified NTO composite energetic material obtained in Example 1;

[0025] Figure 2 This is a digital photo of the burning flame of the high-explosive, heat-insensitive, environmentally friendly fireworks propellant obtained in Example 2 after ignition. DETAILED DESCRIPTION

[0026] In order to have a clearer understanding of the technical features of the present invention, the technical solution of the present invention is now described in detail below, but it should not be construed as limiting the applicable scope of the present invention.

[0027] Example 1

[0028] (1) 20 g of NTO was dissolved in anhydrous ethanol at 80 °C, 2 g of PVA was dissolved in deionized water at 90 °C, the PVA aqueous solution was slowly added to the NTO solution under ultrasonic environment, mechanically stirred at 90 °C for 3 h to mix evenly, and then ultrasonicated at 100 °C and solvent evaporation method was used to obtain the PVA-modified NTO composite energetic material;

[0029] (2) 10 parts of magnesium powder, 15 parts of aluminum powder, and 5 parts of boron powder were dried at 60°C and transferred into a V-type mixer, and 5 parts of manganese dioxide, a pyrotechnic range extender, were added and mixed for 1 hour to obtain an active metal powder mixture;

[0030] (3) adding 1 part of silane coupling agent KH550 to 35 parts of polytetrafluoroethylene powder, mixing them evenly in a mixer, and drying them at 80° C. to obtain modified polytetrafluoroethylene;

[0031] (4) dispersing the active metal powder obtained in step (2), the modified polytetrafluoroethylene powder obtained in step (3), and the NTO energetic composite material obtained in step (1) in polyether polyol, and slowly adding toluene diisocyanate with a functional group ratio of 1:1 to obtain a mixed slurry with polyurethane as an adhesive;

[0032] (5) The mixed slurry obtained in step (4) is extruded and granulated through a granulator with a 2 mm granular plate, and dried at 80° C. to obtain a high-explosive heat-insensitive fireworks propellant product.

[0033] Example 2

[0034] (1) 15 g of NTO was dissolved in anhydrous ethanol at 60 ° C, 1 g of PVA was dissolved in deionized water at 70 ° C, the PVA aqueous solution was slowly added to the NTO solution under ultrasonic environment, mechanically stirred at 85 ° C for 3 h to mix evenly, and then ultrasonicated at 100 ° C and the solvent evaporation method was used to obtain the PVA-modified NTO composite energetic material;

[0035] (2) 8 parts of magnesium powder, 30 parts of aluminum powder, and 3 parts of boron powder were dried at 60°C and transferred into a V-type mixer, and 8 parts of manganese dioxide, a pyrotechnic range extender, were added and mixed for 1 hour to obtain an active metal powder mixture;

[0036] (3) adding 2 parts of silane coupling agent KH550 to 20 parts of polytetrafluoroethylene powder, mixing them evenly in a mixer, and drying them at 80° C. to obtain modified polytetrafluoroethylene;

[0037] (4) dispersing the active metal powder obtained in step (2), the modified polytetrafluoroethylene powder obtained in step (3), and the NTO energetic composite material obtained in step (1) in polyether polyol, and slowly adding diphenylmethane diisocyanate with a functional group ratio of 1:1 to obtain a mixed slurry with polyurethane as an adhesive;

[0038] (5) The mixed slurry obtained in step (4) is extruded and granulated through a granulator with a 2 mm granular plate, and dried at 60° C. to obtain a high-explosive heat-insensitive fireworks propellant product.

[0039] Example 3

[0040] (1) 20 g of NTO was dissolved in anhydrous ethanol at 60 ° C, 2 g of PVA was dissolved in deionized water at 85 ° C, the PVA aqueous solution was slowly added to the NTO solution under ultrasonic environment, mechanically stirred at 85 ° C for 3 h to mix evenly, and then ultrasonicated at 100 ° C and solvent evaporation method was used to obtain PVA modified NTO composite energetic material;

[0041] (2) 5 parts of magnesium powder, 25 parts of aluminum powder, and 4 parts of boron powder were dried at 70°C and transferred into a V-type mixer, and 6 parts of manganese dioxide, a pyrotechnic range extender, were added and mixed for 1 hour to obtain an active metal powder mixture;

[0042] (3) adding 1.5 parts of silane coupling agent KH550 to 30 parts of polytetrafluoroethylene powder, mixing them evenly in a mixer, and drying them at 90° C. to obtain modified polytetrafluoroethylene;

[0043] (4) dispersing the active metal powder obtained in step (2), the modified polytetrafluoroethylene powder obtained in step (3), and the NTO energetic composite material obtained in step (1) in polyether polyol, and slowly adding a mixture of toluene diisocyanate and diphenylmethane diisocyanate with a functional group ratio of 1:1 to obtain a mixed slurry with polyurethane as an adhesive;

[0044] (5) The mixed slurry obtained in step (4) is extruded and granulated through a granulator with a 2 mm granular plate, and dried at 70° C. to obtain a high-explosive heat-insensitive fireworks propellant product.

[0045] Example 4

[0046] (1) 15 g of NTO was dissolved in anhydrous ethanol at 60 °C, and 1 g of PVA was dissolved in deionized water at 85 °C. The PVA aqueous solution was slowly added to the NTO solution under ultrasonic conditions, and mechanically stirred at 85 °C for 3 h to mix evenly. Then, the NTO composite energetic material modified by PVA was obtained by ultrasonication at 100 °C and solvent evaporation method.

[0047] (2) 8 parts of magnesium powder, 20 parts of aluminum powder, and 3 parts of boron powder were dried at 70°C and transferred into a V-type mixer, and 5 parts of manganese dioxide, a pyrotechnic range extender, were added and mixed for 1 hour to obtain an active metal powder mixture;

[0048] (3) adding 1.5 parts of silane coupling agent KH550 to 30 parts of polytetrafluoroethylene powder, mixing them evenly in a mixer, and drying them at 90° C. to obtain modified polytetrafluoroethylene;

[0049] (4) dispersing the active metal powder obtained in step (2), the modified polytetrafluoroethylene powder obtained in step (3), and the NTO energetic composite material obtained in step (1) in polyether polyol, and slowly adding diphenylmethane diisocyanate with a functional group ratio of 1:1 to obtain a mixed slurry with polyurethane as an adhesive;

[0050] (5) The mixed slurry obtained in step (4) is extruded and granulated through a granulator with a 2 mm granular plate, and dried at 70° C. to obtain a high-explosive heat-insensitive fireworks propellant product.

[0051] Example 5

[0052] (1) 15 g of NTO was dissolved in anhydrous ethanol at 60 °C, and 1 g of PVA was dissolved in deionized water at 85 °C. The PVA aqueous solution was slowly added to the NTO solution under ultrasonic conditions, and mechanically stirred at 85 °C for 3 h to mix evenly. Then, the NTO composite energetic material modified by PVA was obtained by ultrasonication at 100 °C and solvent evaporation method.

[0053] (2) 5 parts of magnesium powder, 25 parts of aluminum powder, and 5 parts of boron powder were dried at 70°C and transferred into a V-type mixer, and 8 parts of manganese dioxide, a pyrotechnic range extender, were added and mixed for 1 hour to obtain an active metal powder mixture;

[0054] (3) adding 1.5 parts of silane coupling agent KH550 to 30 parts of polytetrafluoroethylene powder, mixing them evenly in a mixer, and drying them at 90° C. to obtain modified polytetrafluoroethylene;

[0055] (4) dispersing the active metal powder obtained in step (2), the modified polytetrafluoroethylene powder obtained in step (3), and the NTO energetic composite material obtained in step (1) in polyether polyol, and slowly adding isophorone diisocyanate with a functional group ratio of 1:1 to obtain a mixed slurry with polyurethane as an adhesive;

[0056] (5) The mixed slurry obtained in step (4) is extruded and granulated through a granulator with a 2 mm granular plate, and dried at 70° C. to obtain a high-explosive heat-insensitive fireworks propellant product.

[0057] The scanning electron microscope image of the PVA modified NTO composite energetic material obtained in Example 1 is as follows Figure 1 As shown, it can be observed that the high molecular polymer PVA binds the NTO crystals into a spherical state with uniform particle size, which is beneficial to improving the adhesion between NTO and the fireworks propellant system; the digital photo of the burning flame of the fireworks propellant obtained in Example 2 after ignition is shown in Figure 2 As shown, the obtained fireworks propellant burns stably, and the burning flame ejects few particles into the surrounding environment and the flame height is high, indicating that the fireworks propellant burns fully and has stable combustion performance.

[0058] Table 1 Explosion heat and combustion heat parameters of fireworks propellants of Examples 1 to 5

[0059] Example Example 1 Example 2 Example 3 Example 4 Example 5 <![CDATA[Calorific value of detonation (J·g -1 )]]> 6782 6820 6920 7001 6928

[0060] The explosion heat parameters of the fireworks propellants obtained in Examples 1 to 5 are listed in Table 1. The explosion heat values ​​of the fireworks propellants obtained are all higher than 6700 J·g -1 , far exceeding the energy levels of black powder and traditional metal-fluorinated polymer systems, and has the characteristics of high energy and high explosion heat.

Claims

1. A method for preparing high-explosive heat-insensitive environmentally friendly fireworks propellant, characterized in that: The steps include: (1) drying magnesium powder, aluminum powder and boron powder at 60-80° C. and transferring them into a V-type mixer, adding manganese dioxide as a fireworks range extender and mixing for 1-2 hours to obtain an active metal powder mixture; (2) adding silane coupling agent KH550 to polytetrafluoroethylene powder, mixing them evenly in a mixer, and drying them at 80-100° C. to obtain modified polytetrafluoroethylene powder; (3) dispersing the active metal powder mixture obtained in step (1), the modified polytetrafluoroethylene powder obtained in step (2), and the NTO energetic composite material in polyether polyol, and slowly adding diisocyanate to obtain a mixed slurry with polyurethane as an adhesive; (4) The mixed slurry obtained in step (3) is extruded and granulated through a granulator with a 2 mm granular plate, and dried at 60 to 80° C. to obtain a high-explosive heat-insensitive environmentally friendly fireworks propellant.

2. The method for preparing a high-explosive heat-insensitive environmentally friendly fireworks propellant according to claim 1, characterized in that: The materials are configured in the following proportions: The materials in step (1) are as follows: 5-10 parts of magnesium powder, 15-25 parts of aluminum powder, 2-5 parts of boron powder, and 5-8 parts of manganese dioxide in terms of mass fractions; The materials in step (2) are 20 to 35 parts by weight of polytetrafluoroethylene and 1 to 2 parts of a silane coupling agent; The materials in step (3) are as follows: 5 to 15 parts of NTO energetic composite material; 5 to 15 parts of polyurethane adhesive.

3. The method for preparing a high-explosive heat-insensitive environmentally friendly fireworks propellant according to claim 1, characterized in that: The functional group ratio of the polyether polyol to the diisocyanate is 1:1; the diisocyanate is one or more combinations of toluene diisocyanate TDI, diphenylmethane diisocyanate MDI, hexamethylene diisocyanate HDI, and isophorone diisocyanate IPDI.

4. The method for preparing a high-explosive heat-insensitive environmentally friendly fireworks propellant according to claim 1, characterized in that: The preparation process of the NTO energetic composite material comprises the following steps: (1) dissolving the energetic material NTO in anhydrous ethanol at 60-80° C. to obtain an NTO solution; (2) dissolving polyvinyl alcohol (PVA) in deionized water at 80-90° C. to obtain a PVA aqueous solution; (3) The PVA aqueous solution obtained in step (2) is slowly added to the NTO solution obtained in step (1) under an ultrasonic environment, and mechanically stirred at 80 to 90° C. for 2 to 3 hours to mix them evenly, and then ultrasonicated at 100° C. and a solvent evaporation method is used to obtain a PVA-modified NTO energetic composite material.

5. The method for preparing a high-explosive heat-insensitive environmentally friendly fireworks propellant according to claim 4, characterized in that: The mass ratio of NTO to PVA in the NTO energetic composite material is 10-15.

6. A high-explosive, heat-insensitive, environmentally friendly fireworks propellant obtained according to the preparation method according to any one of claims 1 to 5.

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