Moistureproof smokeless firework propellant powder and preparation method thereof

Abstract

The invention discloses a moisture-proof smokeless firework propellant powder and a preparation method thereof. The moistureproof smokeless firework propellant comprises the following components in percentage by mass: 0.5-2% of a dispersing agent, 5-20% of an oxidizing agent ammonium perchlorate, 85-90% of an energetic high polymer material containing nitrocellulose, 1-3% of a centralite, 0.5-2% of liquid paraffin and 0.5-1% of an emulsifying agent, and is prepared by adopting a liquid paraffin emulsification coating method. The preparation method is simple, and the prepared damp-proof smokeless firework propellant powder has the advantages of high burning rate, good stability and excellent damp-proof performance, can be stored for a long time, and can be applied to producing opening powder and propellant powder of fireworks and crackers.

Description

Technical Field

[0001] The invention belongs to the technical field of fireworks propellant, and relates to moisture-proof smokeless fireworks propellant and a preparation method thereof. Background Art

[0002] The burning of fireworks and firecrackers will produce a lot of smoke, polluting the atmosphere and affecting visual perception. Therefore, only by achieving smoke-free fireworks and firecrackers can the development of the fireworks and firecrackers industry be fundamentally solved and meet the ever-increasing environmental protection requirements.

[0003] Although smokeless fireworks propellants can now be used to replace traditional pyrotechnics, they have the defect of being unable to be stored for a long time. Patent CN110845286A discloses a moisture-proof method in which a nitrocellulose solution is sprayed on the surface of the medicine particles, which is smokeless and environmentally friendly, but nitrocellulose will still absorb moisture in a humid environment for a long time, and the moisture-proof effect is greatly reduced. Patent CN115141068A discloses a moisture-proof method in which polyvinyl alcohol is coated with an oxidant ammonium perchlorate, which is environmentally friendly and safe, but the polyvinyl alcohol inside the medicine particles still has a certain hygroscopicity under long-term storage conditions. Patent CN104549078A discloses a process for preparing porous microspheres from nitrocellulose, which has good combustion performance, is smokeless and environmentally friendly, and has high safety performance, but the porous structure will store a small amount of moisture in a humid environment, and long-term storage and moisture absorption will prevent normal combustion. In summary, the current moisture-proof methods cannot maintain good combustion performance while ensuring long-term storage. Summary of the invention

[0004] The purpose of the present invention is to provide a moisture-proof smokeless firework propellant and a preparation method thereof. The firework propellant is smokeless and pollution-free and has normal performance, and at the same time has excellent moisture absorption performance and can have good moisture-proof performance during long-term storage.

[0005] The technical solution for achieving the purpose of the present invention is as follows:

[0006] A moisture-proof smokeless fireworks propellant consists of the following components by mass percentage: 0.5-2% of a dispersant, 5-20% of an oxidant ammonium perchlorate, 85-90% of an energetic polymer material containing nitrocellulose, 1-3% of a neutralizer, 0.5-2% of liquid paraffin, and 0.5-1% of an emulsifier.

[0007] The dispersant described in the present invention is a common dispersant in the field of propellants, which is gum arabic, methylcellulose, polyethylene glycol, gelatin, polyvinyl alcohol or bone glue. In the specific implementation of the present invention, gum arabic is used as a representative example.

[0008] The energetic polymer material containing nitrocellulose described in the present invention is a common energetic polymer material in the field of propellants, and is nitrocellulose, single-base propellant, double-base propellant or modified double-base propellant with a nitrogen content of ≥11.5%.

[0009] The intermediate fixer described in the present invention is a common intermediate fixer in the field of propellants, which is a No. 1 intermediate fixer or a No. 2 intermediate fixer.

[0010] The method for preparing the moisture-proof smokeless fireworks propellant comprises the following steps:

[0011] Step 1, dissolving part of the emulsifier, liquid paraffin and part of the dispersant in water to obtain a paraffin emulsion, wherein the mass concentration of the emulsifier is 0.1-0.5%, the mass concentration of the dispersant is 0.5-2%, the mass concentration of the liquid paraffin is 0.2-1%, and the emulsifier is 0.2-0.5 times the mass of the liquid paraffin; the amount of the paraffin emulsion is 10-30 times the mass of the energetic polymer material containing nitrocellulose; the emulsifier is a nonionic paraffin microemulsifier (NMP), a cationic paraffin microemulsifier (CMP), hexadecyltrimethylammonium bromide, hexadecylammonium chloride or sodium lauryl sulfate;

[0012] Step 2, dissolving the energetic polymer material containing nitrocellulose in ethyl acetate to obtain a polymer sol containing nitrocellulose, wherein the amount of ethyl acetate used is 5 to 30 times the mass of the energetic polymer material containing nitrocellulose;

[0013] Step 3, dissolving the neutralizing agent, the oxidizing agent ammonium perchlorate and the remaining emulsifier in water to obtain an emulsion, wherein the mass concentration of the oxidizing agent is 1-5%, the mass concentration of the emulsifier is 0.2-0.5%, the mass concentration of the neutralizing agent is 1-5%, and the amount of water is 0.1-10.0 times the mass of the ethyl acetate in step 2;

[0014] Step 4, dissolving the remaining dispersant in water to obtain a dispersion having a mass concentration of 0.1 to 2%, wherein the amount of water used is 1 to 3 times the mass of the ethyl acetate in step 2;

[0015] Step 5, adding the emulsion described in step 3 to the polymer sol described in step 2 under stirring conditions, and mixing thoroughly to obtain a polymer emulsion;

[0016] Step 6, dispersing the polymer emulsion described in step 5 into the dispersion described in step 4 under stirring to form spherical droplets;

[0017] Step 7, adding water to the system of step 6, the polymer emulsion forms droplets which gradually harden to form solid particles;

[0018] Step 8, performing solid-liquid separation on the solid particles described in step 7, and drying at room temperature to obtain energetic polymer microspheres;

[0019] Step 9, under stirring conditions, adding the energetic polymer microspheres described in step 8 to the paraffin emulsion described in step 1, wherein the mass of the paraffin emulsion is 20 to 40 times the mass of the energetic polymer microspheres in step 8;

[0020] Step 10, separating the material obtained in step 9 into solid and liquid, drying the separated solid particles, and obtaining moisture-proof smokeless fireworks propellant.

[0021] Preferably, in any one of steps 1 to 10, the material temperature is 10 to 50°C.

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] (1) The preparation method of the present invention is simple and safe and can be prepared at room temperature. Liquid paraffin is used as a moisture-proof agent in a small amount and has little effect on the combustion performance of the propellant;

[0024] (2) The smokeless fireworks propellant of the present invention has the advantages of high burning speed, good stability, and excellent moisture resistance, and can be stored for a long time. DETAILED DESCRIPTION

[0025] The present invention is further described in detail below with reference to specific embodiments.

[0026] Example 1

[0027] (1) A 2-liter three-necked flask was used as a reactor for emulsifying liquid paraffin. Sodium lauryl sulfate, gum arabic, and liquid paraffin were added to water and stirred at room temperature for 12 h to ensure that the liquid paraffin was completely emulsified to form a white emulsion. The concentration of sodium lauryl sulfate was 0.5%, the concentration of liquid paraffin was 1%, and the concentration of gum arabic was 0.5%.

[0028] (2) A 2-liter three-necked flask was used as the pelletizing process of the energetic polymer material. Under stirring, nitrocellulose with a nitrogen content of 11.5% was dissolved in ethyl acetate. In order to prevent the nitrocellulose from sticking to the wall, the nitrocellulose was first added to the reaction bottle, and then ethyl acetate was added to obtain a polymer sol containing nitrocellulose. The sol was stirred at room temperature for 2 hours. The amount of ethyl acetate used was 15 times the mass of the energetic polymer material.

[0029] (3) Under stirring, dissolve the No. 1 neutralizer, ammonium perchlorate and sodium dodecyl sulfate in water, stir at room temperature for 30 minutes to ensure that the No. 1 neutralizer, ammonium perchlorate and sodium dodecyl sulfate are completely dissolved, and slowly add water dropwise into the nitrocellulose polymer sol to form an emulsion, wherein the concentration of the No. 1 neutralizer is 1%, the concentration of ammonium perchlorate is 5%, and the concentration of sodium dodecyl sulfate is 0.5%.

[0030] (4) While stirring, dissolve gum arabic in water to obtain a dispersion. The concentration of gum arabic in water is 1%. Stir at room temperature for 30 minutes to ensure that the dispersant is completely dissolved. The amount of water used is 3 times the mass of ethyl acetate in (2).

[0031] (5) Under stirring conditions, the emulsion in (3) is added to the polymer sol in (2), and the mixture is thoroughly mixed to obtain a polymer emulsion.

[0032] (6) Add the dispersion in (4) to the polymer emulsion in (5), adjust the stirring speed to 500 r / min, and stir at room temperature for 2 h to form spherical droplets.

[0033] (7) Water is added to the system in (6), and the polymer emulsion forms droplets which gradually harden to form solid particles.

[0034] (8) The solid particles in (7) are subjected to solid-liquid separation, usually by filtering to separate the aqueous solution and the solid particles, and then dried at room temperature to obtain energetic polymer microspheres, ensuring that the water content of the polymer microspheres is 20%.

[0035] (9) Under stirring conditions, the air-dried energetic polymer microspheres are added to the paraffin emulsion in (1), wherein the mass of the paraffin emulsion is 20 times the mass of the energetic polymer microspheres. The stirring speed is controlled at 80 r / min and the mixture is stirred at room temperature for 12 h.

[0036] (10) The obtained material is subjected to solid-liquid separation, and the separated solid particles have a water content of 200%, and are dried to obtain moisture-proof smokeless fireworks propellant.

[0037] Example 2

[0038] Using process conditions similar to those in Example 1, the proportions of some materials are changed, wherein (1) the concentration of sodium dodecyl sulfate, the concentration of liquid paraffin, and the concentration of gum arabic are 0.2%, 1%, and 0.5%, respectively. (2) The amount of ethyl acetate used is 15 times the mass of the energetic polymer material. (3) The concentration of the No. 1 stabilizer is 1%, the concentration of ammonium perchlorate is 5%, and the concentration of sodium dodecyl sulfate is 0.5%. (4) The concentration of gum arabic in the aqueous solution is 1%, and the amount of the dispersant aqueous solution is 3 times that of ethyl acetate. (6) The stirring speed is adjusted to 500 r / min. (8) The water content of the energetic polymer microspheres before moisture-proof coating is ensured to be 20%. (9) The mass of the paraffin emulsion is 20 times the mass of the energetic polymer microspheres, and the water content of the separated solid particles is 200%.

[0039] Comparative Example 1

[0040] Using process conditions similar to those in Example 1, the proportions of some materials were changed, wherein (1) the concentration of sodium dodecyl sulfate, the concentration of liquid paraffin, and the concentration of gum arabic were 2%, 1%, and 0.5%, respectively. (2) The amount of ethyl acetate used was 15 times the mass of the energetic polymer material. (3) The concentration of the No. 1 fixative was 1%, and the concentration of ammonium perchlorate in water was 5%. (4) The concentration of gum arabic in the aqueous solution was 1%, and the amount of the dispersant aqueous solution was 3 times that of ethyl acetate. (6) The stirring speed was adjusted to 500 r / min. (8) The water content of the energetic polymer microspheres before moisture-proof coating was ensured to be 20%. (9) The mass of the paraffin emulsion was 20 times the mass of the energetic polymer microspheres, and the water content of the separated solid particles was 200%.

[0041] Comparative Example 2

[0042] Using process conditions similar to those in Example 1, the proportions of some materials are changed, wherein (1) the concentration of sodium dodecyl sulfate is 0.1%, the concentration of liquid paraffin is 1%, and the concentration of gum arabic is 0.5%. (2) The amount of ethyl acetate used is 15 times the mass of the energetic polymer material. (3) The concentration of the No. 1 fixative is 1%, and the concentration of ammonium perchlorate in water is 5%. (4) The concentration of gum arabic in the aqueous solution is 1%, and the amount of the dispersant aqueous solution is 3 times that of ethyl acetate. (6) The stirring speed is adjusted to 500 r / min. (8) The water content of the energetic polymer microspheres before moisture-proof coating is ensured to be 20%. (9) The mass of the paraffin emulsion is 20 times the mass of the energetic polymer microspheres, and the water content of the separated solid particles is 200%.

[0043] Comparative Example 3

[0044] Using process conditions similar to those in Example 1, the proportion of some materials was changed. In (2), the amount of ethyl acetate was 15 times the mass of the energetic polymer material. In (3), the concentration of the No. 1 fixative was 1%, and the concentration of ammonium perchlorate in water was 5%. In (4), the concentration of gum arabic in the aqueous solution was 1%, and the amount of the dispersant aqueous solution was 3 times that of ethyl acetate. In (6), the stirring speed was adjusted to 500 r / min. In (8), the energetic polymer microspheres prepared and formed were dried and not subjected to moisture-proof coating, which served as a blank group.

[0045] According to GB10631-2013 and GJB5384.6-2005 standards, the smokeless fireworks propellants prepared in the embodiments and comparative examples were tested. The results are shown in Table 1.

[0046] Table 1

[0047]

[0048]

[0049] As can be seen from Table 1, the mass ratio of emulsifier to liquid paraffin has a great influence on moisture resistance. When the mass ratio of emulsifier to liquid paraffin is 0.2-0.5, the moisture resistance is good. When the emulsifier content is low, the liquid paraffin cannot be evenly dispersed in water to form a relatively stable emulsion, and the coating performance is poor. When the emulsifier content is high, more emulsifier remains on the particles on the surface of the propellant, which has a certain hygroscopicity and affects the moisture resistance. Adding a small amount of paraffin emulsion on the surface has little effect on the combustion of smokeless fireworks propellants.

[0050] In summary, the present invention adopts the liquid paraffin emulsification coating method, which has uniform coating and good moisture-proof performance. The method of the present invention can uniformly coat the surface of energetic polymer particles with low concentration of moisture-proof agent at room temperature, and compared with the traditional process, it reduces the influence of moisture-proof agent on the burning rate of smokeless propellant.

Claims

1. A moisture-proof smokeless fireworks propellant, characterized in that: Calculated by mass percentage, it is composed of the following ingredients: 0.5~2% dispersant, 5~20% ammonium perchlorate oxidant, 85~90% energetic polymer material containing nitrocellulose, 1~3% neutralizer, 0.5~2% liquid paraffin, and 0.5~1% emulsifier.

2. The moisture-proof smokeless fireworks propellant according to claim 1, characterized in that: The dispersant is gum arabic, methyl cellulose, polyethylene glycol, gelatin, polyvinyl alcohol or bone glue.

3. The moisture-proof smokeless fireworks propellant according to claim 1, characterized in that: The energetic polymer material containing nitrocellulose is nitrocellulose, a single-base drug, a double-base drug or a modified double-base drug with a nitrogen content of ≥11.5%.

4. The moisture-proof smokeless fireworks propellant according to claim 1, characterized in that: The intermediate fixer is intermediate fixer No. 1 or intermediate fixer No.

2.

5. The method for preparing moisture-proof smokeless fireworks propellant according to any one of claims 1 to 4, characterized in that: The following steps are involved: Step 1, dissolving part of the emulsifier, liquid paraffin and part of the dispersant in water to obtain a paraffin emulsion, wherein the mass concentration of the emulsifier is 0.1-0.5%, the mass concentration of the dispersant is 0.5-2%, the mass concentration of the liquid paraffin is 0.2-1%, and the mass of the emulsifier is 0.2-0.5 times the mass of the liquid paraffin; the amount of the paraffin emulsion is 10-30 times the mass of the energetic polymer material containing nitrocellulose; the emulsifier is a nonionic paraffin microemulsifier (NMP), a cationic paraffin microemulsifier (CMP), hexadecyltrimethylammonium bromide, hexadecylammonium chloride or sodium dodecyl sulfate; Step 2, dissolving the energetic polymer material containing nitrocellulose in ethyl acetate to obtain a polymer sol containing nitrocellulose, wherein the amount of ethyl acetate used is 5 to 30 times the mass of the energetic polymer material containing nitrocellulose; Step 3, dissolving the neutralizing agent, the oxidant ammonium perchlorate and the remaining emulsifier in water to obtain an emulsion, wherein the mass concentration of the oxidant is 1-5%, the mass concentration of the emulsifier is 0.2-0.5%, the mass concentration of the neutralizing agent is 1-5%, and the amount of water is 0.1-10.0 times the mass of ethyl acetate in step 2; Step 4, dissolving the remaining dispersant in water to obtain a dispersion with a mass concentration of 0.1-2%, wherein the amount of water used is 1-3 times the mass of ethyl acetate in step 2; Step 5, adding the emulsion described in step 3 to the polymer sol described in step 2 under stirring conditions, and mixing thoroughly to obtain a polymer emulsion; Step 6, dispersing the polymer emulsion described in step 5 into the dispersion described in step 4 under stirring to form spherical droplets; Step 7, adding water to the system of step 6, the polymer emulsion forms droplets which gradually harden to form solid particles; Step 8, performing solid-liquid separation on the solid particles described in step 7, and drying at room temperature to obtain energetic polymer microspheres; Step 9, adding the energetic polymer microspheres described in step 8 to the paraffin emulsion described in step 1 under stirring, wherein the mass of the paraffin emulsion is 20 to 40 times the mass of the energetic polymer microspheres in step 8; Step 10, separating the material obtained in step 9 into solid and liquid, drying the separated solid particles, and obtaining moisture-proof smokeless fireworks propellant.

6. The preparation method according to claim 5, characterized in that: In any step of step 1 to step 10, the material temperature is 10 to 50°C.

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