Ignition head for smoke agent and preparation process of ignition head

Abstract

The invention relates to the technical field of ignition head preparation, in particular to an ignition head for a smoke agent and a preparation process of the ignition head. The invention discloses a preparation process of an ignition head for a smoke agent. The preparation process comprises the following steps: preparing aluminum chloride intercalated expanded graphite, preparing an antistatic hydrophobic coating, preparing a modified starch adhesive and preparing the ignition head for the smoke agent. The preparation method comprises the following steps: firstly, heating microcrystalline cellulose in dilute sulphuric acid for hydrolysis, then carrying out ultrasonication to prepare a nanocellulose suspension, then adding the nanocellulose suspension into a zein solution, fully and uniformly mixing, and forming a primary composite network through hydrogen bond and hydrophobic interaction; the preparation method comprises the following steps: firstly, adding octadecyl methacrylate and azodiisobutyronitrile to carry out a copolymerization reaction, then adding citric acid to carry out a reaction to form a three-dimensional cross-linked network, mixing the three-dimensional cross-linked network with aluminum chloride intercalated expanded graphite and carbon nanotubes to prepare a coating, and uniformly coating the surface of the ignition head to form a coating, so that the moisture resistance of the ignition head can be effectively improved.

Description

Technical Field

[0001] The invention relates to the technical field of ignition head preparation, and in particular to an ignition head for a smoke agent and a preparation process thereof. Background Art

[0002] Smoke sprays, a widely used pesticide formulation, play a key role in pest control. They work by igniting internal chemicals to produce smoke. In practical applications, such as greenhouse vegetable cultivation, traditional spray pesticides tend to increase humidity due to the relatively enclosed space and high humidity. Smoke sprays effectively avoid this problem. Furthermore, smoke sprays are widely used in warehouse pest control and forest pest management due to their ease of use, time-saving labor, and low dosage.

[0003] The ignition of smoke agents relies on the ignition head, and the performance of the ignition head directly affects the proper functioning of the smoke agent. The ignition head is typically formed by mixing and pressing granular components such as oxidizer, combustible material, and regulator. The binder encapsulates and fills the gaps between the particles. Relying on its own viscosity and the cohesive force after cross-linking and curing, it bonds the discrete particles into a single entity with a specific strength and shape, preventing component dispersion or delamination, and ensuring the structural integrity of the ignition head during transportation and storage.

[0004] At present, commonly used ignition head adhesives are mainly divided into natural adhesives and synthetic adhesives. Natural adhesives mainly include gum arabic, starch, gelatin, etc., which are environmentally friendly and easy to degrade, avoiding the release of harmful substances such as formaldehyde in traditional synthetic resins. However, natural adhesives are highly hydrophilic, which causes the ignition head to fail in a humid environment due to moisture absorption, making it difficult to successfully ignite the smoke agent, resulting in the inability to exert its efficacy. In addition, the cohesion is weak and the cross-linking density is low, resulting in insufficient strength of the ignition head. During transportation or extrusion, it is easy to crack or break, reducing the integrity of the ignition head.

[0005] In addition, during the production, transportation and use of the ignition head, when its components rub against equipment, packaging materials or other media, static electricity is easily accumulated due to charge transfer. When the static electricity accumulates to a certain level, it will trigger electrostatic discharge. Although the energy of the instantaneous electric spark is small, it is enough to ignite the flammable components in the ignition head or the surrounding combustible gas / dust, creating a risk of accidental ignition.

[0006] Therefore, it is necessary to provide an ignition head for smoke agent with high strength, moisture resistance and antistatic properties and a preparation process thereof. Summary of the Invention

[0007] In view of the shortcomings of the prior art, the present invention aims to provide an ignition head for smoke agent and a preparation process thereof.

[0008] The present invention provides a process for preparing an ignition head for a smoke agent, comprising the following steps:

[0009] S1: Preparation of aluminum chloride intercalated expanded graphite

[0010] The flake graphite powder and aluminum chloride are mixed and heated to react, and then subjected to high-temperature heat treatment to obtain aluminum chloride intercalated expanded graphite;

[0011] S2: Preparation of antistatic hydrophobic coating

[0012] After preparing microcrystalline cellulose into a nanocellulose suspension, the suspension was mixed with a zein solution, followed by the addition of octadecyl methacrylate and citric acid for reaction, followed by the addition of aluminum chloride to intercalate expanded graphite and carbon nanotubes to obtain an antistatic hydrophobic coating.

[0013] S3: Preparation of modified starch adhesive

[0014] S3.1: Add corn starch to deionized water at a ratio of 1 g to (1.5-2.5) mL. Stir to form a suspension. Heat at 80-90°C under nitrogen for 25-30 min. When the temperature drops to 40-50°C, add 0.1 mol / L hydrochloric acid solution to adjust the pH to 2.5-3 to obtain a gelatinized starch solution.

[0015] S3.2: Dissolve ceric ammonium nitrate in deionized water at a ratio of 1 g to (20-30) mL. Add the solution to the gelatinized starch solution at 40-50°C under nitrogen and stir for 10-20 min. Add ethyl acetoacetate methacrylate and react at 60-70°C with stirring for 2-3 h. After cooling, adjust the pH to 6.5-7 with 0.1 mol / L sodium hydroxide solution to obtain a grafted starch solution.

[0016] S3.3: Dissolve adipic acid dihydrazide in deionized water at a ratio of 1 g to (20-30) mL, add to the grafted starch solution, stir for 1-2 hours, and then mature for 12-24 hours to obtain a modified starch adhesive.

[0017] S4: Preparation of ignition head for smoke agent

[0018] Wood powder and white sugar are crushed and passed through a 100-mesh sieve, then added to alcohol and stirred to mix evenly. Potassium chlorate, potassium nitrate, vaseline and the above-mentioned modified starch adhesive are then added and stirred to mix evenly. The mixture is then pressed into shape and dried to make an ignition head. The above-mentioned antistatic hydrophobic coating is then evenly coated on the surface of the ignition head. After drying and curing, an ignition head for a smoke agent is obtained.

[0019] As a preferred aspect, S1 specifically includes the following steps:

[0020] S1.1: Mix flake graphite powder and aluminum chloride in a drying oven, dry in a vacuum drying oven at 50-60°C for 2-3 hours, then transfer to a reactor and react at 150-180°C with stirring under nitrogen for 2-4 hours to obtain an intermediate.

[0021] S1.2: Wash the intermediate until neutral, then add 1 g of the product to (8-10) mL of 0.1 mol / L dilute hydrochloric acid, stirring for 10-20 min. Vacuum filter and dry to obtain the precursor.

[0022] S1.3: Place the above precursor in a tube furnace, heat it to 800-900°C at a rate of 10-20°C / min, and keep it at this temperature for 20-30 seconds to obtain aluminum chloride intercalated expanded graphite.

[0023] As a preferred aspect, S2 specifically includes the following steps:

[0024] S2.1: Add 1g of microcrystalline cellulose to 3-5wt% sulfuric acid solution in 15-25mL. Heat and hydrolyze at 70-80°C for 2-3h. After cooling, filter and wash until neutral. Disperse in deionized water and ultrasonicate for 30-40min to obtain a nanocellulose suspension with a solid content of 6-8%.

[0025] S2.2: Dissolve zein in 70% ethanol at a ratio of 1 g to (10-20) mL. Stir thoroughly to dissolve. Add the nanocellulose suspension and stir for 30-40 minutes. Then, add glycerol and continue stirring to mix thoroughly to obtain a premix.

[0026] S2.3: Add octadecyl methacrylate and azobisisobutyronitrile to the above premixed solution, heat and stir at 70-80°C under nitrogen protection for 2-3 hours, then add citric acid, and adjust the pH to 3.5-4 with 0.1 mol / L hydrochloric acid solution, continue to keep warm and stir for 1.5-2.5 hours, after cooling, add aluminum chloride intercalated expanded graphite and carbon nanotubes obtained in step S1.3, and ultrasonically disperse for 10-20 minutes to obtain an antistatic hydrophobic coating.

[0027] As a preferred aspect, the mass ratio of flake graphite powder to aluminum chloride is (1.3-1.5):1.

[0028] As a preferred aspect, the mass ratio of cellulose to zein in the nanocellulose suspension is 1:(6-8), and the amount of glycerol added is 3-4% of the mass of zein.

[0029] As a preferred aspect, the mass ratio of octadecyl methacrylate to zein is 1:(2-3), the mass ratio of azobisisobutyronitrile to octadecyl methacrylate is 1:(38-42), and the mass ratio of citric acid to octadecyl methacrylate is 1:(6-8).

[0030] As a preferred aspect, the amounts of aluminum chloride intercalated expanded graphite and carbon nanotubes added to the antistatic hydrophobic coating are 6-8 wt % and 1-2 wt %, respectively.

[0031] As a preferred aspect, the addition amount of ammonium cerium nitrate is 0.5-1.5% of the mass of corn starch, the addition amount of ethyl acetoacetate methacrylate is 15-20% of the mass of corn starch, and the molar ratio of adipic acid dihydrazide to ethyl acetoacetate methacrylate is 1:(1-2).

[0032] As a preferred aspect, the raw material composition of the ignition head is, by mass, 15-25 parts of wood flour, 10-20 parts of white sugar, 15-25 parts of potassium chlorate, 30-40 parts of potassium nitrate, 1-3 parts of vaseline, 5-10 parts of modified starch adhesive and 25-35 parts of alcohol.

[0033] A smoke agent ignition head is prepared by any of the above-mentioned processes for preparing a smoke agent ignition head.

[0034] The present invention has the following advantages:

[0035] 1. In the present invention, microcrystalline cellulose is first heated and hydrolyzed in dilute sulfuric acid, and then ultrasonically crushed to form a nanocellulose suspension, which is then added to a zein solution and thoroughly mixed to form a preliminary composite network through hydrogen bonding and hydrophobic interaction. Octadecyl methacrylate and azobisisobutyronitrile are then added for copolymerization, and then citric acid is added for reaction to form a three-dimensional cross-linked network. The coating is mixed with aluminum chloride intercalated expanded graphite and carbon nanotubes to form a coating, and the coating is evenly applied to the surface of the ignition head to form a coating. On the one hand, the introduction of the hydrophobic alkyl chain of octadecyl methacrylate can form a dense low surface energy barrier, increase the water contact angle of the coating, and significantly hinder the penetration of water molecules. On the other hand, the nanocellulose, aluminum chloride intercalated expanded graphite, and carbon nanotubes form a multi-level rough structure in the coating, which traps air to form an air cushion layer, makes water droplets spherical, reduces the solid-liquid contact area, and further repels liquid water. After the citric acid cross-linking forms a three-dimensional network, the coating density can be increased, the water molecule diffusion path is blocked, and the coating swelling rate is significantly reduced, thereby effectively improving the moisture resistance of the ignition head.

[0036] 2. In the present invention, after flake graphite powder and aluminum chloride are dried, they are reacted under nitrogen protection to sublime anhydrous aluminum chloride, and gaseous aluminum chloride molecules are embedded in the graphite layers. The temperature is then rapidly increased, so that the gas generated between the layers expands the graphite sheets and expands the volume, thereby obtaining fluffy and porous aluminum chloride intercalated expanded graphite. After adding the fluffy and porous aluminum chloride intercalated expanded graphite together with carbon nanotubes to the coating, the porous structures formed by the aluminum chloride intercalated expanded graphite overlap with each other to form a long-range conductive path. At the same time, the decomposition products of aluminum chloride cover the graphite surface, providing ionic conductivity, thereby giving the coating conductivity. In addition, the aluminum chloride intercalated expanded graphite forms a micron-sized conductive framework in the coating, and the carbon nanotubes are interspersed between the pores of the aluminum chloride intercalated expanded graphite, enhancing the interface contact points, thereby achieving the effect of synergistically improving the conductivity of the coating, thereby enabling the smoke agent ignition head to have better antistatic properties and eliminating the risk of accidental ignition caused by static electricity during the production or storage and transportation of the smoke agent.

[0037] 3. In the present invention, after corn starch is gelatinized, it is grafted with ethyl acetoacetate methacrylate under the initiation of ammonium cerium nitrate to generate a graft copolymer with ketone carbonyl groups in the side chain. Adipic acid dihydrazide is then added for cross-linking to obtain a modified starch adhesive. When the modified starch adhesive is used as an adhesive component to prepare a smoke agent ignition head, the ethyl acetoacetate methacrylate side chain can form a nano-scale hard phase. At the same time, the covalent bond network formed by ketone hydrazide cross-linking is stronger than the physically entangled ordinary starch glue, so that the ignition head can resist external extrusion without cracking or breaking. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a flow chart of the process for preparing the ignition head for smoke agent used in an embodiment of the present invention. DETAILED DESCRIPTION

[0039] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0040] Example 1, a process for preparing a smoke ignition head, such as Figure 1 As shown, the following steps are included:

[0041] S1: Preparation of aluminum chloride intercalated expanded graphite

[0042] S1.1: Flake graphite powder and aluminum chloride were mixed in a drying oven, dried in a vacuum drying oven at 50°C for 2 h, and then transferred to a reactor. Under nitrogen protection, the mixture was stirred at 150°C for 2 h to obtain an intermediate, wherein the mass ratio of flake graphite powder to aluminum chloride was 1.3:1.

[0043] S1.2: Wash the intermediate until neutral, then add 1 g to 8 mL of 0.1 mol / L dilute hydrochloric acid and stir for 10 min. Vacuum filter and dry to obtain the precursor.

[0044] S1.3: Place the above precursor in a tube furnace, raise the temperature to 800°C at a rate of 10°C / min, and hold the temperature for 20 seconds to obtain aluminum chloride intercalated expanded graphite;

[0045] S2: Preparation of antistatic hydrophobic coating

[0046] S2.1: Add 1 g of microcrystalline cellulose to 3 wt% sulfuric acid solution at a ratio of 15 mL and heat to hydrolyze at 70°C for 2 h. After cooling, filter and wash until neutral, disperse in deionized water, and ultrasonicate for 30 min to obtain a nanocellulose suspension with a solid content of 6%.

[0047] S2.2: Dissolve zein in 70% ethanol at a ratio of 1 g:10 mL. Stir thoroughly to dissolve. Add the nanocellulose suspension and stir for 30 minutes. Then, add glycerol and continue stirring to mix thoroughly to obtain a premix. The mass ratio of cellulose to zein in the nanocellulose suspension is 1:6, and the amount of glycerol added is 3% of the mass of zein.

[0048] S2.3: Add octadecyl methacrylate and azobisisobutyronitrile to the above premixed solution, heat and stir at 70°C for 2 hours under nitrogen protection, then add citric acid, and adjust the pH to 3.5 with 0.1 mol / L hydrochloric acid solution. Continue to keep warm and stir for 1.5 hours. After cooling, add the aluminum chloride intercalated expanded graphite and carbon nanotubes prepared in step S1.3, and ultrasonically disperse for 10 minutes to obtain an antistatic hydrophobic coating, wherein the mass ratio of octadecyl methacrylate to zein is 1:2, the mass ratio of azobisisobutyronitrile to octadecyl methacrylate is 1:38, and the mass ratio of citric acid to octadecyl methacrylate is 1:6. The amounts of aluminum chloride intercalated expanded graphite and carbon nanotubes added to the antistatic hydrophobic coating are 6 wt% and 1 wt%, respectively.

[0049] S3: Preparation of modified starch adhesive

[0050] S3.1: Add corn starch to deionized water at a ratio of 1 g:1.5 mL, stir to form a suspension, and heat at 80°C under nitrogen for 25 min. When the temperature drops to 40°C, add 0.1 mol / L hydrochloric acid solution to adjust the pH to 2.5 to obtain a gelatinized starch solution.

[0051] S3.2: Dissolve ammonium cerium nitrate in deionized water at a ratio of 1 g:20 mL. Add the solution to the gelatinized starch solution at 40°C under nitrogen and stir for 10 min. Then, add ethyl acetoacetate methacrylate and react at 60°C with stirring for 2 h. After cooling, adjust the pH to 6.5 with 0.1 mol / L sodium hydroxide solution to obtain a grafted starch solution. The amount of ammonium cerium nitrate added is 0.5% by weight of the corn starch, and the amount of ethyl acetoacetate methacrylate added is 15% by weight of the corn starch.

[0052] S3.3: Dissolve adipic acid dihydrazide in deionized water at a ratio of 1 g:20 mL, add the mixture to the grafted starch solution, stir for 1 h, and ripen for 12 h to obtain a modified starch adhesive, wherein the molar ratio of adipic acid dihydrazide to ethyl methyl acetoacetate is 1:1.

[0053] S4: Preparation of ignition head for smoke agent

[0054] Wood flour and white sugar are crushed and passed through a 100-mesh sieve, then added to alcohol and stirred to mix evenly. Potassium chlorate, potassium nitrate, vaseline and the above-mentioned modified starch adhesive are then added and stirred to mix evenly. The mixture is pressed into shape and dried to make an ignition head. The above-mentioned antistatic hydrophobic coating is then evenly coated on the surface of the ignition head. After drying and curing, an ignition head for a smoke agent is obtained. The raw material composition of the ignition head is, by mass, 15 parts of wood flour, 10 parts of white sugar, 15 parts of potassium chlorate, 30 parts of potassium nitrate, 1 part of vaseline, 5 parts of modified starch adhesive and 25 parts of alcohol.

[0055] Example 2, a process for preparing a smoke ignition head, such as Figure 1 As shown, the following steps are included:

[0056] S1: Preparation of aluminum chloride intercalated expanded graphite

[0057] S1.1: Flake graphite powder and aluminum chloride were mixed in a drying oven, dried in a vacuum drying oven at 55°C for 2.5 hours, and then transferred to a reactor. Under nitrogen protection, the mixture was stirred at 165°C for 3 hours to obtain an intermediate, wherein the mass ratio of flake graphite powder to aluminum chloride was 1.4:1.

[0058] S1.2: Wash the intermediate until neutral, then add 1 g to 9 mL of 0.1 mol / L dilute hydrochloric acid and stir for 15 min. Vacuum filter and dry to obtain the precursor.

[0059] S1.3: Place the above precursor in a tube furnace, increase the temperature to 850°C at a rate of 15°C / min, and hold the temperature for 25 seconds to obtain aluminum chloride intercalated expanded graphite;

[0060] S2: Preparation of antistatic hydrophobic coating

[0061] S2.1: Add 1 g of microcrystalline cellulose to 4 wt% sulfuric acid solution in a 20 mL volumetric ratio. Heat and hydrolyze at 75°C for 2.5 h. After cooling, filter and wash until neutral, disperse in deionized water, and ultrasonicate for 35 min to obtain a nanocellulose suspension with a solids content of 7%.

[0062] S2.2: Dissolve zein in 70% ethanol at a ratio of 1 g:15 mL. Stir thoroughly to dissolve. Add the nanocellulose suspension and stir for 35 minutes. Then, add glycerol and continue stirring to mix thoroughly to obtain a premix. The mass ratio of cellulose to zein in the nanocellulose suspension is 1:7, and the amount of glycerol added is 3.5% of the mass of zein.

[0063] S2.3: Add octadecyl methacrylate and azobisisobutyronitrile to the above premixed solution, heat and stir the mixture at 75°C for 2.5 hours under nitrogen protection, then add citric acid, and adjust the pH to 3.8 with 0.1 mol / L hydrochloric acid solution. Continue to stir and stir the mixture for 2 hours. After cooling, add the aluminum chloride intercalated expanded graphite and carbon nanotubes prepared in step S1.3, and ultrasonically disperse them for 15 minutes to obtain an antistatic hydrophobic coating, wherein the mass ratio of octadecyl methacrylate to zein is 1:2.5, the mass ratio of azobisisobutyronitrile to octadecyl methacrylate is 1:40, and the mass ratio of citric acid to octadecyl methacrylate is 1:7. The amounts of aluminum chloride intercalated expanded graphite and carbon nanotubes added to the antistatic hydrophobic coating are 7 wt% and 1.5 wt%, respectively.

[0064] S3: Preparation of modified starch adhesive

[0065] S3.1: Add corn starch to deionized water at a ratio of 1 g:2 mL, stir to form a suspension, and then heat at 85°C under nitrogen for 28 min. When the temperature drops to 45°C, add 0.1 mol / L hydrochloric acid solution to adjust the pH to 2.8 to obtain a gelatinized starch solution.

[0066] S3.2: Dissolve ammonium cerium nitrate in deionized water at a ratio of 1 g:25 mL. Add the solution to the gelatinized starch solution at 45°C under nitrogen and stir for 15 min. Then, add ethyl acetoacetate methacrylate and react at 65°C with stirring for 2.5 h. After cooling, adjust the pH to 6.8 with 0.1 mol / L sodium hydroxide solution to obtain a grafted starch solution. The amount of ammonium cerium nitrate added is 1% by weight of the corn starch, and the amount of ethyl acetoacetate methacrylate is 18% by weight of the corn starch.

[0067] S3.3: Dissolve adipic acid dihydrazide in deionized water at a ratio of 1 g:25 mL, add the mixture to the grafted starch solution, stir for 1.5 h, and ripen for 18 h to obtain a modified starch adhesive, wherein the molar ratio of adipic acid dihydrazide to ethyl methacrylate is 1:1.5.

[0068] S4: Preparation of ignition head for smoke agent

[0069] Wood flour and white sugar are crushed and passed through a 100-mesh sieve, and then added to alcohol and stirred to mix evenly. Potassium chlorate, potassium nitrate, vaseline and the above-mentioned modified starch adhesive are then added and stirred to mix evenly. The mixture is pressed into shape and dried to make an ignition head. The above-mentioned antistatic hydrophobic coating is then evenly coated on the surface of the ignition head. After drying and curing, an ignition head for a smoke agent is obtained. The raw material composition of the ignition head is, by mass, 20 parts of wood flour, 15 parts of white sugar, 20 parts of potassium chlorate, 35 parts of potassium nitrate, 2 parts of vaseline, 7.5 parts of modified starch adhesive and 30 parts of alcohol.

[0070] Example 3, a process for preparing a smoke ignition head, such as Figure 1 As shown, the following steps are included:

[0071] S1: Preparation of aluminum chloride intercalated expanded graphite

[0072] S1.1: Flake graphite powder and aluminum chloride were mixed in a drying oven, dried in a vacuum drying oven at 60°C for 3 h, and then transferred to a reactor. Under nitrogen protection, the mixture was stirred at 180°C for 4 h to obtain an intermediate, wherein the mass ratio of flake graphite powder to aluminum chloride was 1.5:1.

[0073] S1.2: Wash the intermediate until neutral, then add 1 g to 10 mL of 0.1 mol / L dilute hydrochloric acid and stir for 20 min. Vacuum filter and dry to obtain the precursor.

[0074] S1.3: Place the above precursor in a tube furnace, raise the temperature to 900°C at 20°C / min, and hold the temperature for 30 seconds to obtain aluminum chloride intercalated expanded graphite;

[0075] S2: Preparation of antistatic hydrophobic coating

[0076] S2.1: Add 1 g of microcrystalline cellulose to 5 wt% sulfuric acid solution in 25 mL of water, heat and hydrolyze at 80°C for 3 h, cool, filter, wash until neutral, disperse in deionized water, and ultrasonicate for 40 min to obtain a nanocellulose suspension with a solid content of 8%.

[0077] S2.2: Dissolve zein in 70% ethanol at a ratio of 1 g:20 mL. Stir thoroughly to dissolve. Add the nanocellulose suspension and stir for 40 minutes. Then, add glycerol and continue stirring to mix thoroughly to obtain a premix. The mass ratio of cellulose to zein in the nanocellulose suspension is 1:8, and the amount of glycerol added is 4% of the mass of zein.

[0078] S2.3: Add octadecyl methacrylate and azobisisobutyronitrile to the above premixed solution, heat and stir the mixture at 80°C for 3 hours under nitrogen protection, then add citric acid, and adjust the pH to 4 with 0.1 mol / L hydrochloric acid solution. Continue to keep warm and stir the mixture for 1.5-2.5 hours. After cooling, add the aluminum chloride intercalated expanded graphite and carbon nanotubes prepared in step S1.3, and ultrasonically disperse for 20 minutes to obtain an antistatic hydrophobic coating, wherein the mass ratio of octadecyl methacrylate to zein is 1:3, the mass ratio of azobisisobutyronitrile to octadecyl methacrylate is 1:42, and the mass ratio of citric acid to octadecyl methacrylate is 1:8. The amounts of aluminum chloride intercalated expanded graphite and carbon nanotubes added to the antistatic hydrophobic coating are 8 wt% and 2 wt%, respectively.

[0079] S3: Preparation of modified starch adhesive

[0080] S3.1: Add corn starch to deionized water at a ratio of 1 g:2.5 mL, stir to form a suspension, and heat at 90°C under nitrogen for 30 min. When the temperature drops to 50°C, add 0.1 mol / L hydrochloric acid solution to adjust the pH to 3 to obtain a gelatinized starch solution.

[0081] S3.2: Dissolve ammonium cerium nitrate in deionized water at a ratio of 1 g:30 mL. Add the solution to the gelatinized starch solution at 50°C under nitrogen and stir for 20 min. Then, add ethyl acetoacetate methacrylate and react at 70°C with stirring for 3 h. After cooling, adjust the pH to 7 with 0.1 mol / L sodium hydroxide solution to obtain a grafted starch solution. The amount of ammonium cerium nitrate added is 1.5% by weight of the corn starch, and the amount of ethyl acetoacetate methacrylate added is 20% by weight of the corn starch.

[0082] S3.3: Dissolve adipic acid dihydrazide in deionized water at a ratio of 1 g:30 mL, add the mixture to the grafted starch solution, stir for 2 h, and ripen for 24 h to obtain a modified starch adhesive, wherein the molar ratio of adipic acid dihydrazide to ethyl methyl acetoacetate is 1:2.

[0083] S4: Preparation of ignition head for smoke agent

[0084] Wood flour and white sugar are crushed and passed through a 100-mesh sieve, and then added to alcohol and stirred to mix evenly. Potassium chlorate, potassium nitrate, vaseline and the above-mentioned modified starch adhesive are then added and stirred to mix evenly. The mixture is pressed into shape and dried to make an ignition head. The above-mentioned antistatic hydrophobic coating is then evenly coated on the surface of the ignition head. After drying and curing, an ignition head for a smoke agent is obtained. The raw material composition of the ignition head is, by mass, 25 parts of wood flour, 20 parts of white sugar, 25 parts of potassium chlorate, 40 parts of potassium nitrate, 3 parts of vaseline, 10 parts of modified starch adhesive and 35 parts of alcohol.

[0085] Comparative Example 1: The difference between Comparative Example 1 and Example 1 is that the step of coating the antistatic hydrophobic coating on the surface of the ignition head in step S4 is removed, that is, the ignition head is not coated with a protective coating.

[0086] Comparative Example 2: The difference between Comparative Example 2 and Example 1 is that the carbon nanotubes in step S2.3 are replaced by an equal amount of aluminum chloride intercalated expanded graphite.

[0087] Comparative Example 3: The difference between Comparative Example 3 and Example 1 is that the aluminum chloride intercalated expanded graphite in step S2.3 is replaced by an equal amount of carbon nanotubes.

[0088] Comparative Example 4: The difference between Comparative Example 4 and Example 1 is that the modified starch adhesive in step S4 is replaced by an equal amount of corn starch.

[0089] Test example:

[0090] Test 1: 100 smoke igniters prepared in Examples 1-3 and Comparative Example 1 were placed in a sealed container with a humidity of 80%. After standing at room temperature for 30 days, 30 of each were randomly selected for ignition testing. The results are shown in Table 1.

[0091] Table 1: Test results of moisture resistance of smoke ignition head

[0092] Ignition rate (%) Example 1 100 Example 2 100 Example 3 100 Comparative Example 1 53.3

[0093] As can be seen from Table 1 above, in Comparative Example 1, after the antistatic hydrophobic coating is not used to coat the surface of the ignition head, the ignition rate of the smoke agent ignition head obtained is much lower than that of Example 1. It can be seen that by first heating and hydrolyzing microcrystalline cellulose in dilute sulfuric acid, and then ultrasonically crushing it to form a nanocellulose suspension, adding it to the zein solution, mixing it thoroughly, forming a preliminary composite network through hydrogen bonding and hydrophobic interactions, and then adding octadecyl methacrylate and azobisisobutyronitrile to carry out copolymerization, and then adding citric acid to react to form a three-dimensional cross-linked network, which is mixed with aluminum chloride intercalated expanded graphite and carbon nanotubes to form a coating, and evenly coated on the surface of the ignition head to form a coating, the moisture-proof performance of the ignition head can be effectively improved.

[0094] Test 2: The antistatic hydrophobic coatings prepared in Examples 1-3, Comparative Example 2 and Comparative Example 3 were coated in a drying dish. After drying and curing, sample films were obtained. The surface resistance of the sample films was then tested. The results are shown in Table 2.

[0095] Table 2: Surface resistance test results of antistatic hydrophobic coating

[0096] Surface resistance (Ω) Example 1 <![CDATA[2.85×10 5 ]]> Example 2 <![CDATA[2.36×10 5 ]]> Example 3 <![CDATA[2.14×10 5 ]]> Comparative Example 2 <![CDATA[6.48×10 7 ]]> Comparative Example 3 <![CDATA[2.26×10 6 ]]>

[0097] As can be seen from Table 2 above, when only single aluminum chloride intercalation expanded graphite or single carbon nanotube is used in Comparative Example 2 and Comparative Example 3, the surface resistance of the obtained antistatic hydrophobic coating is higher than that in Example 1. It can be seen that after the flake graphite powder and aluminum chloride are dried, they are reacted under nitrogen protection, anhydrous aluminum chloride is sublimed, and gaseous aluminum chloride molecules are embedded in the graphite interlayer, and then rapidly heated, so that the gas generated between the layers is propped open the graphite sheet, and the volume is expanded to obtain fluffy and porous aluminum chloride intercalation expanded graphite. After adding it to the coating together with the carbon nanotubes, the two can achieve the effect of synergistically improving the conductivity of the coating, so that the smoke agent ignition head can have better antistatic performance, eliminating the risk of accidental ignition caused by static electricity during smoke agent production or storage and transportation.

[0098] Test 3: The compressive strength of the ignition heads prepared in Examples 1-3 and Comparative Example 4 was tested. The results are shown in Table 3.

[0099] Table 3: Ignition head compressive strength test results

[0100] Compressive strength (MPa) Example 1 2.1 Example 2 2.1 Example 3 2.2 Comparative Example 4 0.8

[0101] As can be seen from Table 3 above, when the modified starch binder is replaced with ordinary corn starch as the binder in Comparative Example 4, the compressive strength of the resulting ignition head is much lower than that in Example 1. This shows that after the corn starch is gelatinized, it is grafted with ethyl acetoacetate methacrylate under the initiation of ammonium ceric nitrate to form a graft copolymer containing ketone carbonyl groups in the side chain, and then adipic acid dihydrazide is added for cross-linking to obtain a modified starch binder. When this binder is used as a binder component to prepare an ignition head for a smoke agent, the ignition head can resist external extrusion without cracking or breaking.

[0102] It should be understood that those skilled in the art may make improvements or modifications based on the above description, and all such improvements and modifications shall fall within the scope of protection of the appended claims. Any portion of this specification not described in detail is prior art known to those skilled in the art.

Claims

1. A process for preparing an ignition head for a smoke agent, characterized in that: The steps include: S1: Preparation of aluminum chloride intercalated expanded graphite The flake graphite powder and aluminum chloride are mixed and heated to react, and then subjected to high-temperature heat treatment to obtain aluminum chloride intercalated expanded graphite; S2: Preparation of antistatic hydrophobic coating After preparing microcrystalline cellulose into a nanocellulose suspension, the suspension was mixed with a zein solution, followed by the addition of octadecyl methacrylate and citric acid for reaction, followed by the addition of aluminum chloride to intercalate expanded graphite and carbon nanotubes to obtain an antistatic hydrophobic coating. S3: Preparation of modified starch adhesive S3.1: Add corn starch to deionized water at a ratio of 1 g to (1.5-2.5) mL. Stir to form a suspension. Heat at 80-90°C under nitrogen for 25-30 min. When the temperature drops to 40-50°C, add 0.1 mol / L hydrochloric acid solution to adjust the pH to 2.5-3 to obtain a gelatinized starch solution. S3.2: Dissolve ceric ammonium nitrate in deionized water at a ratio of 1 g to (20-30) mL. Add the solution to the gelatinized starch solution at 40-50°C under nitrogen and stir for 10-20 min. Add ethyl acetoacetate methacrylate and react at 60-70°C with stirring for 2-3 h. After cooling, adjust the pH to 6.5-7 with 0.1 mol / L sodium hydroxide solution to obtain a grafted starch solution. S3.3: Dissolve adipic acid dihydrazide in deionized water at a ratio of 1 g to (20-30) mL, add to the grafted starch solution, stir for 1-2 hours, and then mature for 12-24 hours to obtain a modified starch adhesive. S4: Preparation of ignition head for smoke agent Wood powder and white sugar are crushed and passed through a 100-mesh sieve, then added to alcohol and stirred to mix evenly. Potassium chlorate, potassium nitrate, vaseline and the above-mentioned modified starch adhesive are then added and stirred to mix evenly. The mixture is then pressed into shape and dried to make an ignition head. The above-mentioned antistatic hydrophobic coating is then evenly coated on the surface of the ignition head. After drying and curing, an ignition head for a smoke agent is obtained.

2. The process for preparing a smoke generator ignition head according to claim 1, characterized in that: S1 specifically includes the following steps: S1.1: Mix flake graphite powder and aluminum chloride in a drying oven, dry in a vacuum drying oven at 50-60°C for 2-3 hours, then transfer to a reactor and react at 150-180°C with stirring under nitrogen for 2-4 hours to obtain an intermediate. S1.2: Wash the intermediate until neutral, then add 1 g of the product to (8-10) mL of 0.1 mol / L dilute hydrochloric acid, stirring for 10-20 min. Vacuum filter and dry to obtain the precursor. S1.3: Place the above precursor in a tube furnace, heat it to 800-900°C at a rate of 10-20°C / min, and keep it at this temperature for 20-30 seconds to obtain aluminum chloride intercalated expanded graphite.

3. The process for preparing a smoke agent ignition head according to claim 2, characterized in that: S2 specifically includes the following steps: S2.1: Add 1g of microcrystalline cellulose to 3-5wt% sulfuric acid solution in 15-25mL. Heat and hydrolyze at 70-80°C for 2-3h. After cooling, filter and wash until neutral. Disperse in deionized water and ultrasonicate for 30-40min to obtain a nanocellulose suspension with a solid content of 6-8%. S2.2: Dissolve zein in 70% ethanol at a ratio of 1 g to (10-20) mL. Stir thoroughly to dissolve. Add the nanocellulose suspension and stir for 30-40 minutes. Then, add glycerol and continue stirring to mix thoroughly to obtain a premix. S2.3: Add octadecyl methacrylate and azobisisobutyronitrile to the above premixed solution, heat and stir at 70-80°C under nitrogen protection for 2-3 hours, then add citric acid, and adjust the pH to 3.5-4 with 0.1 mol / L hydrochloric acid solution, continue to keep warm and stir for 1.5-2.5 hours, after cooling, add aluminum chloride intercalated expanded graphite and carbon nanotubes obtained in step S1.3, and ultrasonically disperse for 10-20 minutes to obtain an antistatic hydrophobic coating.

4. The process for preparing a smoke agent ignition head according to claim 2, characterized in that: The mass ratio of flake graphite powder to aluminum chloride is (1.3-1.5):

1.

5. The process for preparing a smoke generator ignition head according to claim 3, characterized in that: The mass ratio of cellulose to zein in the nanocellulose suspension is 1:(6-8), and the amount of glycerol added is 3-4% of the mass of zein.

6. The process for preparing a smoke agent ignition head according to claim 3, characterized in that: The mass ratio of octadecyl methacrylate to zein is 1:(2-3), the mass ratio of azobisisobutyronitrile to octadecyl methacrylate is 1:(38-42), and the mass ratio of citric acid to octadecyl methacrylate is 1:(6-8).

7. The process for preparing a smoke generator ignition head according to claim 3, characterized in that: The addition amounts of aluminum chloride intercalated expanded graphite and carbon nanotubes in the antistatic hydrophobic coating are 6-8wt% and 1-2wt% respectively.

8. The process for preparing a smoke generator ignition head according to claim 1, characterized in that: The amount of ammonium cerium nitrate added is 0.5-1.5% of the mass of corn starch, the amount of ethyl acetoacetate added is 15-20% of the mass of corn starch, and the molar ratio of adipic acid dihydrazide to ethyl acetoacetate is 1:(1-2).

9. The process for preparing a smoke generator ignition head according to claim 1, characterized in that: The raw material composition of the ignition head is as follows: 15-25 parts of wood flour, 10-20 parts of white sugar, 15-25 parts of potassium chlorate, 30-40 parts of potassium nitrate, 1-3 parts of vaseline, 5-10 parts of modified starch adhesive and 25-35 parts of alcohol.

10. A smoke agent ignition head, characterized in that: The smoke ignition head is prepared by the preparation process of the smoke agent ignition head according to any one of claims 1 to 9.

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