Fire extinguishing agent and preparation method thereof

Abstract

The invention relates to the technical field of fire extinguishing materials, in particular to a fire extinguishing agent and a preparation method thereof.The fire extinguishing agent is prepared from, by weight, 18-20 parts of composite solution, 1.5-2.2 parts of modified silicon dioxide, 0.3-0.4 part of calcium carbonate and 0.08-0.1 part of preservation.The shell material silicon dioxide of the fire extinguishing agent is modified, a composite cross-linking agent is added into a core material composite solution of the fire extinguishing agent, and the fire extinguishing agent is prepared. The problem that an existing dry water fire extinguishing agent shell material is unstable in structure is solved, and meanwhile the fire extinguishing effect is greatly improved.

Description

Technical Field

[0001] The invention relates to the technical field of fire extinguishing materials, and in particular to a fire extinguishing agent and a preparation method thereof. Background Art

[0002] With the development of new energy vehicles, its battery energy storage industry has developed rapidly. Among them, lithium-ion batteries, as one of the main electrochemical energy storage carriers, are widely used due to their advantages such as high energy density, environmental friendliness, and long cycle life. However, lithium battery fire and explosion accidents still occur frequently, posing a serious threat to people's lives and property safety. Due to the inherent characteristics of lithium-ion batteries, when they catch fire, they involve three types of fire, A, B, and C, and it is difficult to extinguish the fire. Dry water fire extinguishing agent, as a special fire extinguishing agent, can have a certain fire extinguishing effect in lithium-ion battery fires. However, due to its own defects, that is, the unstable shell-core structure, it is very easy to break and lose its effectiveness during storage and transportation. At the same time, its own fire extinguishing effect cannot meet the fire extinguishing needs of lithium-ion batteries. Summary of the invention

[0003] The purpose of the present invention is to provide a fire extinguishing agent and a preparation method thereof. By modifying the silica shell material of the fire extinguishing agent and adding a composite cross-linking agent to its core material composite solution, the problem of unstable shell material structure of the existing dry water fire extinguishing agent is solved, and at the same time, its fire extinguishing effect is greatly improved.

[0004] The purpose of the present invention can be achieved by the following technical scheme: A method for preparing a fire extinguishing agent comprises the following steps: weighing the following raw materials in parts by weight: 18-20 parts of a composite solution, 1.5-2.2 parts of modified silicon dioxide, 0.3-0.4 parts of calcium carbonate and 0.08-0.1 parts of a preservative, mixing the composite solution, modified silicon dioxide, calcium carbonate and preservative, stirring for 45 seconds at a temperature of 35° C. and a stirring rate of 10000 rpm, and standing to obtain a fire extinguishing agent; The composite solution is prepared by the following steps: Step A1: phosphorus trichloride and dichloromethane are mixed, and under nitrogen protection, the stirring rate is 300-360rpm, the temperature is -10°C, 1,1'-ferrocenedimethanol is added with stirring, and the reaction is carried out for 1-1.5h, and then the temperature is raised to 5°C, and the reaction is continued for 4-6h, and intermediate 1, 3-hydroxypyridine and dichloromethane are mixed, and under the stirring rate is 200-240rpm, the temperature is 5°C, triethylamine is added with stirring, and the reaction is carried out for 4-6h to obtain intermediate 2; The ratio of phosphorus trichloride to 1,1'-ferrocenedimethanol is 0.1-0.11 mol: 0.03-0.04 mol; the ratio of intermediate 1,3-hydroxypyridine to triethylamine is 0.01-0.012 mol: 0.05-0.06 mol: 0.06 mol; During the reaction, the hydroxyl group in 1,1'-ferrocenedimethanol undergoes a substitution reaction with phosphorus trichloride to obtain intermediate 1, and the chlorine in intermediate 1 then undergoes a substitution reaction with the hydroxyl group in 3-hydroxypyridine to obtain intermediate 2; Step A2: Mix the intermediate 2, 4-(2-bromoethoxy)benzaldehyde and acetonitrile, and react for 24 hours under nitrogen protection, at a stirring rate of 80-120 rpm and a temperature of 70° C. to obtain a composite cross-linking agent; The ratio of the composite cross-linking agent, 4-(2-bromoethoxy)benzaldehyde and acetonitrile is 0.06-0.08 mol: 0.28-0.3 mol: 80-90 mL; During the reaction, bromine in 4-(2-bromoethoxy)benzaldehyde reacts with the pyridine group in intermediate 2 to form a quaternary ammonium structure to obtain a composite cross-linking agent; Step A3: Sodium alginate and deionized water are mixed, stirred at a stirring rate of 300-400 rpm and room temperature for 10-15 minutes, chitosan solution and composite cross-linking agent are added, ultrasonically dispersed for 40 minutes, and stirred for 30-40 minutes to obtain a composite solution; The mass fraction of chitosan solution is 1%, and the dosage ratio of sodium alginate, deionized water, chitosan solution and composite cross-linking agent is 1.2-1.4 g: 15-20 mL: 100-110 mL: 0.08-0.1 g; The modified silicon dioxide is prepared by the following steps: Step B1: Mix nano-silica and ethanol, stir at a rate of 120-140 rpm, and add ammonia water and 3-(isobutyleneoxy)propyltrimethylsilane, and react for 12 hours to obtain precursor 1. Mix precursor 1, 4-aminosalicylic acid and N,N-dimethylformamide, stir at a rate of 180-240 rpm, and add triethylamine, and react for 4-6 hours to obtain precursor 2. The mass fraction of ammonia water is 25%, the dosage ratio of nano-silica, ethanol, ammonia water and 3-(isobutylene acyloxy)propyltrimethylsilane is 0.3-0.35g: 26-28mL: 0.05-0.08mL: 0.4-0.5mL; the dosage ratio of precursor 1, 4-aminosalicylic acid, N,N-dimethylformamide and triethylamine is 0.5-0.52g: 0.001-0.0012mol: 40-42mL: 0.8-0.9g; During the reaction, the siloxy groups in 3-(isobutyleneoxy)propyltrimethylsilane are hydrolyzed and react with the hydroxyl groups on the surface of nano-silica, and are grafted onto the nano-silica to obtain precursor 1. Then, under the condition of triethylamine as an acid-binding agent, the double bond in precursor 1 undergoes Michael addition with the amino group in 4-aminosalicylic acid to obtain precursor 2. Step B2: 1-vinylimidazole and tetrahydrofuran are mixed, stirred at a stirring rate of 120-140 rpm and room temperature, 1,3-propane sultone is added, and the reaction is carried out for 24 hours to obtain intermediate a; intermediate a is mixed with deionized water, stirred at a stirring rate of 180-200 rpm and a temperature of 80°C, sulfuric acid solution is added, and the reaction is carried out for 3-4 hours to obtain intermediate b; 1-vinylimidazole, tetrahydrofuran and 1,3-propane sultone 0.04-0.05mol:80-100mL:0.04-0.05mol; the molar concentration of sulfuric acid solution is 0.1mol / L, and the amount ratio of intermediate a, deionized water and sulfuric acid solution is 0.01-0.012mol:10-15mL:80-90mL; During the reaction, 1,3-propane sultone is ring-opened and reacts with 1-vinyl imidazole to form an imidazolium structure and introduce a sulfonic acid group to obtain an intermediate a. The sulfonic acid group in the intermediate a is then converted into a sulfonic acid group in a sulfuric acid solution to obtain an intermediate b. Step B3: Precursor 2, boric acid and acetonitrile are mixed, lithium carbonate is added at a stirring rate of 180-200 rpm and a temperature of 40°C, and the reaction is carried out for 3-4 hours, and salicylic acid is added, and the reaction is continued for 6-8 hours to obtain precursor 3, and precursor 3, intermediate b, deionized water and ethanol are mixed, and the reaction is carried out for 2 hours at a stirring rate of 120-140 rpm and a temperature of 60°C to obtain modified silica; The ratio of precursor 2, boric acid, lithium carbonate and salicylic acid is 0.4-0.45g: 0.001-0.0011mol: 0.08-0.1g: 0.001mol; the ratio of precursor 3 and intermediate b is 0.35-0.38g: 0.0008-0.001mol; During the reaction, under the action of lithium carbonate, the salicylic acid group in precursor 2 and salicylic acid combine with boric acid to form an anionic structure to obtain precursor 3. Since intermediate b contains a cationic imidazolium structure, it undergoes an ion exchange reaction with precursor 3 to obtain modified silica. Beneficial effects of the invention: The invention discloses a fire extinguishing agent and a preparation method thereof. The fire extinguishing agent shell material silica is modified and a composite cross-linking agent is added to the core material composite solution, thereby solving the problem of unstable shell material structure of the existing dry water fire extinguishing agent and greatly improving the fire extinguishing effect. In the preparation process of the fire extinguishing agent, since the surface of the modified silica is grafted with an ionic structure containing a sulfonic acid group, it gradually dissociates during the stirring process and reacts with calcium carbonate, thereby replacing calcium ions. The presence of calcium ions causes the composite solution containing chitosan and sodium alginate to gradually form a gel structure. At the same time, since the composite solution contains a composite cross-linking agent, its aldehyde group reacts with chitosan and sodium alginate to form a cross-linked structure. Due to the hydrogen bonds and ionic bonds between the modified silica itself and the gel structure after dissociation, the stability of its shell structure is improved. Since the composite cross-linking agent itself contains ferrocene and phosphate structures, it can produce a chemical fire extinguishing effect during fire extinguishing, effectively terminating the chain reaction when the lithium ion battery catches fire. The characteristics of the modified silica itself and the boron element it contains enable it to effectively isolate oxygen during fire extinguishing to achieve a fire extinguishing effect. DETAILED DESCRIPTION

[0005] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0006] Example 1 A method for preparing a fire extinguishing agent comprises the following steps: weighing the following raw materials in parts by weight: 18 parts of a composite solution, 1.5 parts of modified silicon dioxide, 0.3 parts of commercially available Yufeng 037 calcium carbonate, and 0.08 parts of commercially available Tianshi Landun 722 preservative, mixing the composite solution, modified silicon dioxide, calcium carbonate, and preservative, stirring for 45 seconds at a temperature of 35° C. and a stirring rate of 10,000 rpm, and standing to prepare a fire extinguishing agent; The composite solution is prepared by the following steps: Step A1: phosphorus trichloride and dichloromethane were mixed, and 1,1'-ferrocenedimethanol was added under nitrogen protection, stirring at a rate of 300 rpm and a temperature of -10°C, and the mixture was reacted for 1 hour, and then the temperature was raised to 5°C and the reaction was continued for 4 hours. Intermediate 1, 3-hydroxypyridine and dichloromethane were mixed, and triethylamine was added under stirring at a rate of 200 rpm and a temperature of 5°C and the reaction was continued for 4 hours to obtain intermediate 2; The ratio of phosphorus trichloride and 1,1'-ferrocenedimethanol is 0.1mol:0.03mol; the ratio of intermediate 1,3-hydroxypyridine and triethylamine is 0.01mol:0.05mol:0.06mol; Step A2: The intermediate 2, 4-(2-bromoethoxy)benzaldehyde and acetonitrile were mixed, and the mixture was reacted for 24 hours under nitrogen protection, a stirring rate of 80 rpm, and a temperature of 70° C. to obtain a composite cross-linking agent; The ratio of the composite cross-linking agent, 4-(2-bromoethoxy)benzaldehyde and acetonitrile is 0.06 mol: 0.28 mol: 800 mL; Step A3: Mix commercially available Liqia sodium alginate and deionized water, stir for 10 min at a stirring rate of 300 rpm and room temperature, then add commercially available Liqia chitosan solution and composite crosslinking agent and ultrasonically disperse for 40 min, and continue stirring for 30 min to obtain a composite solution; The mass fraction of chitosan solution is 1%, and the dosage ratio of sodium alginate, deionized water, chitosan solution and composite cross-linking agent is 1.2g:15mL:100mL:0.08g; The modified silicon dioxide is prepared by the following steps: Step B1: Mix nano-silica and ethanol, stir at a stirring rate of 120 rpm and a temperature of 60°C, add ammonia water and 3-(isobutyleneoxy)propyltrimethylsilane, and react for 12 hours to obtain precursor 1; mix precursor 1, 4-aminosalicylic acid and N,N-dimethylformamide, stir at a stirring rate of 180 rpm and a temperature of 50°C, add triethylamine, and react for 4 hours to obtain precursor 2; The mass fraction of ammonia water is 25%, the dosage ratio of nano-silica, ethanol, ammonia water and 3-(isobutylene acyloxy)propyltrimethylsilane is 0.3g:26mL:0.05mL:0.4mL; the dosage ratio of precursor 1, 4-aminosalicylic acid, N,N-dimethylformamide and triethylamine is 0.5g:0.001mol:40mL:0.8g; Step B2: 1-vinylimidazole and tetrahydrofuran were mixed, and 1,3-propane sultone was added under stirring at a rate of 120 rpm and room temperature, and the mixture was reacted for 24 hours to obtain intermediate a; intermediate a was mixed with deionized water, and sulfuric acid solution was added under stirring at a rate of 180 rpm and a temperature of 80°C, and the mixture was reacted for 3-4 hours to obtain intermediate b; 1-vinylimidazole, tetrahydrofuran and 1,3-propane sultone 0.04mol:80mL:0.04mol; the molar concentration of sulfuric acid solution is 0.1mol / L, and the amount ratio of intermediate a, deionized water and sulfuric acid solution is 0.01mol:10mL:80mL; Step B3: Precursor 2, boric acid and acetonitrile were mixed, lithium carbonate was added at a stirring rate of 180 rpm and a temperature of 40°C, and the reaction was continued for 3 hours, and salicylic acid was added, and the reaction was continued for 6 hours to obtain precursor 3. Precursor 3, intermediate b, deionized water and ethanol were mixed, and the reaction was continued for 2 hours at a stirring rate of 120 rpm and a temperature of 60°C to obtain modified silica; The usage ratio of precursor 2, boric acid, lithium carbonate and salicylic acid is 0.4g:0.001mol:0.08g:0.001mol; the usage ratio of precursor 3 and intermediate b is 0.35g:0.0008mol.

[0007] Example 2 A method for preparing a fire extinguishing agent comprises the following steps: weighing the following raw materials in parts by weight: 20 parts of a composite solution, 1.5 parts of modified silicon dioxide, 0.4 parts of commercially available Yufeng 037 calcium carbonate and 0.08 parts of commercially available Tianshi Landun 722 preservative, mixing the composite solution, modified silicon dioxide, calcium carbonate and preservative, stirring for 45 seconds at a temperature of 35° C. and a stirring rate of 10,000 rpm, and standing to obtain a fire extinguishing agent; The composite solution is prepared by the following steps: Step A1: phosphorus trichloride and dichloromethane were mixed, and 1,1'-ferrocenedimethanol was added under nitrogen protection, stirring at a rate of 360 rpm and a temperature of -10°C, and the mixture was reacted for 1.5 hours, and then the temperature was raised to 5°C and the reaction was continued for 4 hours. Intermediate 1, 3-hydroxypyridine and dichloromethane were mixed, and triethylamine was added under stirring at a rate of 240 rpm and a temperature of 5°C, and the reaction was continued for 4 hours to obtain intermediate 2; The ratio of phosphorus trichloride to 1,1'-ferrocenedimethanol was 0.11 mol:0.03 mol; the ratio of intermediate 1,3-hydroxypyridine to triethylamine was 0.01 mol:0.06 mol:0.06 mol; Step A2: Mix the intermediate 2, 4-(2-bromoethoxy)benzaldehyde and acetonitrile, and react for 24 hours under nitrogen protection, at a stirring rate of 120 rpm and a temperature of 70° C. to obtain a composite cross-linking agent; The ratio of composite cross-linking agent, 4-(2-bromoethoxy)benzaldehyde and acetonitrile is 0.06 mol: 0.3 mol: 80 mL; Step A3: Mix commercially available Licha sodium alginate and deionized water, stir for 15 min at a stirring rate of 300 rpm and room temperature, then add commercially available Licha chitosan solution and composite crosslinking agent and ultrasonically disperse for 40 min, and continue stirring for 40 min to obtain a composite solution; The mass fraction of chitosan solution is 1%, and the dosage ratio of sodium alginate, deionized water, chitosan solution and composite cross-linking agent is 1.4g:15mL:110mL:0.08g; The modified silicon dioxide is prepared by the following steps: Step B1: Mix nano-silica and ethanol, stir at a rate of 140 rpm, and add ammonia water and 3-(isobutyleneoxy)propyltrimethylsilane, and react for 12 hours to obtain precursor 1. Mix precursor 1, 4-aminosalicylic acid and N,N-dimethylformamide, stir at a rate of 180 rpm, and add triethylamine, and react for 6 hours to obtain precursor 2. The mass fraction of ammonia water is 25%, the dosage ratio of nano-silica, ethanol, ammonia water and 3-(isobutylene acyloxy)propyltrimethylsilane is 0.3g:28mL:0.05mL:0.5mL; the dosage ratio of precursor 1, 4-aminosalicylic acid, N,N-dimethylformamide and triethylamine is 0.5g:0.0012mol:40mL:0.9g; Step B2: 1-vinylimidazole and tetrahydrofuran were mixed, stirred at a stirring rate of 120 rpm and room temperature, 1,3-propane sultone was added, and the mixture was reacted for 24 hours to obtain intermediate a; intermediate a was mixed with deionized water, stirred at a stirring rate of 200 rpm and a temperature of 80° C., sulfuric acid solution was added, and the mixture was reacted for 3 hours to obtain intermediate b; 1-vinylimidazole, tetrahydrofuran and 1,3-propane sultone 0.05mol:100mL:0.04mol; the molar concentration of sulfuric acid solution is 0.1mol / L, and the amount ratio of intermediate a, deionized water and sulfuric acid solution is 0.01mol:10mL:90mL; Step B3: Precursor 2, boric acid and acetonitrile were mixed, lithium carbonate was added at a stirring rate of 180 rpm and a temperature of 40°C, and the reaction was continued for 4 hours, and salicylic acid was added, and the reaction was continued for 8 hours to obtain precursor 3. Precursor 3, intermediate b, deionized water and ethanol were mixed, and the reaction was continued for 2 hours at a stirring rate of 120 rpm and a temperature of 60°C to obtain modified silica; The usage ratio of precursor 2, boric acid, lithium carbonate and salicylic acid is 0.45g:0.0011mol:0.08g:0.001mol; the usage ratio of precursor 3 and intermediate b is 0.35g:0.001mol.

[0008] Example 3 A method for preparing a fire extinguishing agent comprises the following steps: weighing the following raw materials in parts by weight: 20 parts of a composite solution, 2.2 parts of modified silicon dioxide, 0.4 parts of commercially available Yufeng 037 calcium carbonate, and 0.1 parts of commercially available Tianshi Landun 722 preservative, mixing the composite solution, modified silicon dioxide, calcium carbonate, and preservative, stirring for 45 seconds at a temperature of 35° C. and a stirring rate of 10,000 rpm, and standing to obtain a fire extinguishing agent; The composite solution is prepared by the following steps: Step A1: phosphorus trichloride and dichloromethane were mixed, and under nitrogen protection, the stirring rate was 360 rpm, the temperature was -10°C, 1,1'-ferrocenedimethanol was added with stirring, and the reaction was continued for 1.5 hours, and then the temperature was raised to 5°C, and the reaction was continued for 4-6 hours. Intermediate 1, 3-hydroxypyridine and dichloromethane were mixed, and under the stirring rate of 240 rpm, the temperature was 5°C, triethylamine was added with stirring, and the reaction was continued for 6 hours to obtain intermediate 2; The ratio of phosphorus trichloride to 1,1'-ferrocenedimethanol was 0.11 mol:0.04 mol; the ratio of intermediate 1,3-hydroxypyridine to triethylamine was 0.012 mol:0.06 mol:0.06 mol; Step A2: Mix the intermediate 2, 4-(2-bromoethoxy)benzaldehyde and acetonitrile, and react for 24 hours under nitrogen protection, at a stirring rate of 120 rpm and a temperature of 70° C. to obtain a composite cross-linking agent; The ratio of composite cross-linking agent, 4-(2-bromoethoxy)benzaldehyde and acetonitrile is 0.08 mol: 0.3 mol: 90 mL; Step A3: Mix commercially available Licha sodium alginate and deionized water, stir for 15 min at a stirring rate of 400 rpm and room temperature, then add commercially available Licha chitosan solution and composite crosslinking agent and ultrasonically disperse for 40 min, and continue stirring for 40 min to obtain a composite solution; The mass fraction of chitosan solution is 1%, and the dosage ratio of sodium alginate, deionized water, chitosan solution and composite cross-linking agent is 1.4g:20mL:110mL:0.1g; The modified silicon dioxide is prepared by the following steps: Step B1: Mix nano-silica and ethanol, stir at a rate of 140 rpm, and add ammonia water and 3-(isobutyleneoxy)propyltrimethylsilane, and react for 12 hours to obtain precursor 1. Mix precursor 1, 4-aminosalicylic acid and N,N-dimethylformamide, stir at a rate of 240 rpm, and add triethylamine, and react for 6 hours to obtain precursor 2. The mass fraction of ammonia water is 25%, the dosage ratio of nano-silica, ethanol, ammonia water and 3-(isobutylene acyloxy)propyltrimethylsilane is 0.35g:28mL:0.08mL:0.5mL; the dosage ratio of precursor 1, 4-aminosalicylic acid, N,N-dimethylformamide and triethylamine is 0.52g:0.0012mol:42mL:0.9g; Step B2: 1-vinylimidazole and tetrahydrofuran were mixed, and 1,3-propane sultone was added under stirring at a rate of 140 rpm and room temperature, and the mixture was reacted for 24 hours to obtain intermediate a; intermediate a was mixed with deionized water, and sulfuric acid solution was added under stirring at a rate of 200 rpm and a temperature of 80° C., and the mixture was reacted for 4 hours to obtain intermediate b; 1-vinylimidazole, tetrahydrofuran and 1,3-propane sultone 0.05mol:100mL:0.05mol; the molar concentration of sulfuric acid solution is 0.1mol / L, and the amount ratio of intermediate a, deionized water and sulfuric acid solution is 0.012mol:15mL:90mL; Step B3: Precursor 2, boric acid and acetonitrile were mixed, lithium carbonate was added at a stirring rate of 200 rpm and a temperature of 40°C, and the reaction was continued for 4 hours, and salicylic acid was added, and the reaction was continued for 8 hours to obtain precursor 3. Precursor 3, intermediate b, deionized water and ethanol were mixed, and the reaction was continued for 2 hours at a stirring rate of 140 rpm and a temperature of 60°C to obtain modified silica; The usage ratio of precursor 2, boric acid, lithium carbonate and salicylic acid is 0.45g:0.0011mol:0.1g:0.001mol; the usage ratio of precursor 3 and intermediate b is 0.38g:0.001mol.

[0009] Comparative Example 1 Compared with Example 3, this comparative example is different in that 1,1'-ferrocenedimethanol in the preparation process of the composite solution in Example 3 is replaced by p-phenylenedimethanol, and the other steps are the same.

[0010] Comparative Example 2 Compared with Example 3, this comparative example is different in that the modified silica in the fire extinguishing agent preparation process of Example 3 is replaced by commercially available Jingshengyuan JQ001 nano-silica, and the other steps are the same.

[0011] Take a fire extinguishing agent prepared in Example 1, Example 2, Example 3, Comparative Example 1 and Comparative Example 2, spread the fire extinguishing agent in a glass dish, and place a weight of 500g on it for 10min, remove the weight, centrifuge, record the exudate to evaluate its pressure resistance, place the fire extinguishing agent in a drying oven at a temperature of 50°C for 7d, calculate its mass loss rate to evaluate its water retention performance, take a 3.7V ternary polymer soft-pack lithium battery as a battery sample, place it in a combustion chamber, fill 100g of fire extinguishing agent in a portable powder sprayer, heat the lithium battery, spray the fire extinguishing agent after it burns, record the amount of fire extinguishing agent used during the fire extinguishing, and record the time it takes for the temperature to drop to 100°C to evaluate its fire extinguishing performance. The test results are as follows: Test items Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Exudate volume (mL) 0.8 0.9 0.8 0.9 2.6 Mass loss rate (%) 12.83 12.67 12.41 13.10 21.83 Amount of fire extinguishing agent (g) 77.41 75.93 75.27 84.36 98.15 Cooling time (s) 245.1 241.6 239.7 321.2 295.1 It can be seen from the test results in the table shown that when Example 1, Example 2 and Example 3 are compared with Comparative Example 1 and Comparative Example 2, Comparative Example 1 replaces 1,1'-ferrocenedimethanol in the preparation process of the composite solution of Example 3 with p-terephthalenedimethanol. Due to the lack of ferrocenyl groups, its fire extinguishing effect is reduced. Comparative Example 2 replaces the modified silica in the preparation process of the fire extinguishing agent of Example 3 with commercially available nano-silica. Due to the lack of modification, its stability performance is reduced.

[0012] In the description of the specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0013] The above contents are merely examples and explanations of the concept of the present invention. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the concept of the invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. A method for preparing a fire extinguishing agent, characterized in that: The method comprises the following steps: weighing the following raw materials in parts by weight: 18-20 parts of a composite solution, 1.5-2.2 parts of modified silicon dioxide, 0.3-0.4 parts of calcium carbonate and 0.08-0.1 parts of a preservative, mixing the composite solution, the modified silicon dioxide, the calcium carbonate and the preservative, stirring for 45 seconds at a temperature of 35° C. and a stirring rate of 10000 rpm, and standing to obtain a fire extinguishing agent.

2. The method for preparing a fire extinguishing agent according to claim 1, characterized in that: The composite solution is prepared by the following steps: Step A1: phosphorus trichloride and dichloromethane are mixed, and under nitrogen protection, the stirring rate is 300-360rpm, the temperature is -10°C, 1,1'-ferrocenedimethanol is added with stirring, and the reaction is carried out for 1-1.5h, and then the temperature is raised to 5°C, and the reaction is continued for 4-6h, and intermediate 1, 3-hydroxypyridine and dichloromethane are mixed, and under the stirring rate is 200-240rpm, the temperature is 5°C, triethylamine is added with stirring, and the reaction is carried out for 4-6h to obtain intermediate 2; Step A2: Mix the intermediate 2, 4-(2-bromoethoxy)benzaldehyde and acetonitrile, and react for 24 hours under nitrogen protection, stirring at a rate of 80-120 rpm, and a temperature of 70° C. to obtain a composite cross-linking agent; Step A3: Sodium alginate and deionized water are mixed, stirred at a stirring rate of 300-400 rpm at room temperature for 10-15 minutes, chitosan solution and composite crosslinking agent are added and ultrasonically dispersed for 40 minutes, and stirring is continued for 30-40 minutes to obtain a composite solution.

3. The method for preparing a fire extinguishing agent according to claim 2, characterized in that: In step A1: the ratio of phosphorus trichloride to 1,1'-ferrocenedimethanol is 0.1-0.11 mol: 0.03-0.04 mol; the ratio of intermediate 1, 3-hydroxypyridine to triethylamine is 0.01-0.012 mol: 0.05-0.06 mol: 0.06 mol.

4. The method for preparing a fire extinguishing agent according to claim 2, characterized in that: In step A2, the ratio of the composite cross-linking agent, 4-(2-bromoethoxy)benzaldehyde and acetonitrile is 0.06-0.08 mol: 0.28-0.3 mol: 80-90 mL.

5. The method for preparing a fire extinguishing agent according to claim 2, characterized in that: In step A3: the mass fraction of the chitosan solution is 1%, and the amount ratio of sodium alginate, deionized water, chitosan solution and composite cross-linking agent is 1.2-1.4 g: 15-20 mL: 100-110 mL: 0.08-0.1 g.

6. The method for preparing a fire extinguishing agent according to claim 1, characterized in that: The modified silicon dioxide is prepared by the following steps: Step B1: Mix nano-silica and ethanol, stir at a rate of 120-140 rpm, and add ammonia water and 3-(isobutyleneoxy)propyltrimethylsilane, and react for 12 hours to obtain precursor 1. Mix precursor 1, 4-aminosalicylic acid and N,N-dimethylformamide, stir at a rate of 180-240 rpm, and add triethylamine, and react for 4-6 hours to obtain precursor 2. Step B2: 1-vinylimidazole and tetrahydrofuran are mixed, stirred at a stirring rate of 120-140 rpm and room temperature, 1,3-propane sultone is added, and the reaction is carried out for 24 hours to obtain intermediate a; intermediate a is mixed with deionized water, stirred at a stirring rate of 180-200 rpm and a temperature of 80°C, sulfuric acid solution is added, and the reaction is carried out for 3-4 hours to obtain intermediate b; Step B3: Mix precursor 2, boric acid and acetonitrile, add lithium carbonate at a stirring rate of 180-200 rpm and a temperature of 40°C, react for 3-4 hours, then add salicylic acid and continue to react for 6-8 hours to obtain precursor 3, mix precursor 3, intermediate b, deionized water and ethanol, and react for 2 hours at a stirring rate of 120-140 rpm and a temperature of 60°C to obtain modified silica.

7. The method for preparing a fire extinguishing agent according to claim 6, characterized in that: In step B1: the mass fraction of ammonia water is 25%, the amount ratio of nano-silica, ethanol, ammonia water and 3-(isobutylene acyloxy)propyltrimethylsilane is 0.3-0.35g:26-28mL:0.05-0.08mL:0.4-0.5mL; the amount ratio of precursor 1, 4-aminosalicylic acid, N,N-dimethylformamide and triethylamine is 0.5-0.52g:0.001-0.0012mol:40-42mL:0.8-0.9g.

8. The method for preparing a fire extinguishing agent according to claim 6, characterized in that: In step B2: 1-vinylimidazole, tetrahydrofuran and 1,3-propane sultone 0.04-0.05 mol: 80-100 mL: 0.04-0.05 mol; the molar concentration of the sulfuric acid solution is 0.1 mol / L, and the amount ratio of the intermediate a, deionized water and sulfuric acid solution is 0.01-0.012 mol: 10-15 mL: 80-90 mL.

9. The method for preparing a fire extinguishing agent according to claim 6, characterized in that: In step B3: the amount ratio of precursor 2, boric acid, lithium carbonate and salicylic acid is 0.4-0.45g: 0.001-0.0011mol: 0.08-0.1g: 0.001mol; the amount ratio of precursor 3 and intermediate b is 0.35-0.38g: 0.0008-0.001mol.

10. A fire extinguishing agent, characterized in that: Prepared according to any one of claims 1 to 9.