Aerogel water-based fire extinguishing agent and its preparation method and application

Abstract

The present application belongs to the technical field of fire extinguishing materials, and particularly relates to an aerogel water-based fire extinguishing agent, a preparation method and application thereof. The aerogel water-based fire extinguishing agent comprises the following components by weight percentage: aerogel flame retardant 5-40 wt%; dispersant 0.1-1 wt%; thixotropic agent 0-0.5 wt%; stabilizer 0-1 wt%; emulsifier 0.5-5 wt%; and water 52.5-94.4 wt%. The gel flame retardant is used in the present application, and in the fire extinguishing process, the aerogel particles can form an aerogel heat preservation layer after the fire extinguishing agent is completely volatilized, which prevents the too fast volatilization of the central part of the fire extinguishing agent, so that it can pass through the flame and reach the center of the fire source. The aerogel particles are adsorbed on the surface of the burning material, and the central part of the fire extinguishing agent continues to volatilize and cool down, directly reducing the temperature of the center of the fire source, effectively overcoming the defect that the traditional pure liquid fire extinguishing agent often volatilizes completely when reaching the center of the fire source, and it is often difficult to spray into the center of the fire source when the fire is very large.

Description

Technical Field

[0001] This invention belongs to the field of fire extinguishing materials technology, specifically relating to an aerogel water-based fire extinguishing agent, its preparation method, and its application. Background Technology

[0002] Fire extinguishers are essential fire-fighting equipment in our daily lives. Common extinguishing agents include foam extinguishing agents, water-based extinguishing agents, dry powder extinguishing agents, and gaseous extinguishing agents. Compared to other extinguishing agents, water-based extinguishing agents offer high cost-effectiveness and excellent fire-extinguishing performance, effectively improving the actual fire-fighting efficiency of frontline firefighters and minimizing damage to the surrounding ecological environment of burning buildings. Therefore, they have a significant development advantage in the fire extinguishing agent market. Despite the many advantages of water-based extinguishing agents, it is still necessary to further enhance their fire-extinguishing efficiency by incorporating additives into the water. These additives improve the agent's adhesion, heat insulation, flame retardancy, and oxygen barrier properties. By effectively extending the contact time between water and the burning material and minimizing the flow resistance of the extinguishing agent itself, the fire-extinguishing efficiency can be significantly improved. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides an aerogel-based water-based fire extinguishing agent, its preparation method, and its application.

[0004] The technical solution provided by this invention is as follows:

[0005] A method for preparing an aerogel flame retardant includes the following steps:

[0006] 1) Prepare an aqueous dispersion of the flame retardant, adjust the pH to neutral, and ensure the solid content in the aqueous dispersion is 2-10%;

[0007] 2) Water glass is used as raw material. After desalination, an aqueous silica sol is obtained as an aerogel precursor. The pH value can be adjusted to make it stable for storage. The solid content of silica is 10-20%.

[0008] 3) Mix the aqueous dispersion of the flame retardant obtained in step 1) and the aqueous silica sol obtained in step 2) at a weight ratio of (0.5-1):1, stir evenly, maintain the temperature at 15-25℃, and stir and disperse for 30-60 minutes to obtain a uniformly mixed silica aerogel precursor containing flame retardant.

[0009] 4) Adjust the pH of the silica aerogel precursor containing flame retardant obtained in step 3) to between 4 and 6, and place it in a water bath environment at 50 to 60°C for gelation and aging for 1 to 3 hours.

[0010] 5) Activate the gel obtained in step 4) in a hydrochloric acid or sulfuric acid solution with a mass concentration of more than 15%, and make the mass concentration of acid in the gel greater than 10%.

[0011] 6) Take out the activated gel from step 5), immerse the gel in a liquid of hexamethyldisiloxane, seal and heat to 55-65°C for modification treatment. To improve the modification efficiency, a small amount of trimethylchlorosilane can be added.

[0012] 7) After modification, the material is dried. The drying temperature is set at 65-75℃ for 1.5-2.5 hours, at 90-100℃ for 2.5-3.5 hours, and at 105-115℃ for 3.5-5.5 hours to obtain the aerogel flame retardant. Preferably, the drying temperature is set at 70℃ for 2 hours, 95℃ for 3 hours, and 110℃ for 4 hours.

[0013] The above technical solution utilizes the high specific area of ​​aerogels in aerogel flame retardants by adsorbing, modifying, or grafting commercially available high-efficiency flame retardants onto the surface of the aerogel, resulting in a novel aerogel-structured high-efficiency flame retardant. This type of flame retardant can maintain its size within the nanoscale range, maximizing its flame-retardant properties, while also possessing the highly efficient fire-resistant and heat-insulating properties of aerogels. By dispersing the aerogel flame retardant in water and adding other relevant additives for water-based fire extinguishers, an extinguishing liquid is formed and filled into a high-pressure fire extinguisher, thereby achieving highly efficient fire suppression.

[0014] Specifically, in step 1), the flame retardant is a phosphorus-nitrogen flame retardant, a nitrogen-based flame retardant, or a red phosphorus flame retardant.

[0015] The present invention also provides an aerogel flame retardant prepared by the above preparation method.

[0016] The present invention also provides an aerogel water-based fire extinguishing agent, comprising the following components in weight percentages: 5-40 wt% aerogel flame retardant; 0.1-1 wt% dispersant; 0-0.5 wt% thixotropic agent; 0-1 wt% stabilizer; 0.5-5 wt% emulsifier; and 52.5-94.4 wt% water.

[0017] Specifically, the dispersant is selected from Dow ACUMER 445N, ACUMER 9300, 2500, DISPARON AQ-320, DISPARON AQ-330, or King's dispersant K-SPERSE A503.

[0018] Specifically, the thixotropic agent is selected from methylcellulose, hydroxypropyl methylcellulose, hydroxyethylcellulose, or carboxymethylcellulose.

[0019] Specifically, the stabilizer is selected from carbomer, sodium alginate, or sodium polyacrylate.

[0020] Specifically, the emulsifier is selected from bentonite, kaolin, montmorillonite, or diatomaceous earth.

[0021] The present invention also provides a method for preparing an aerogel water-based fire extinguishing agent, comprising the following steps: mixing the components according to the amount of the formula to obtain the aerogel water-based fire extinguishing agent.

[0022] This invention also provides the application of aerogel water-based fire extinguishing agents for the manufacture of water-based fire extinguishers.

[0023] The beneficial effects of this invention are as follows:

[0024] 1. The formulation uses aerogel-modified non-halogenated flame retardant. By grafting aerogel onto the surface of a flame retardant containing N and P, the process of preparing fire-retardant liquid using this aerogel-modified flame retardant is simple and can be directly added to water. Moreover, the prepared fire-retardant liquid has good flame retardant and heat insulation properties, which solves the problem that aerogel is difficult to add to aqueous systems and has poor stability.

[0025] 2. During the fire extinguishing process, after the extinguishing agent has evaporated, the aerogel particles can form an aerogel insulation layer, which prevents the extinguishing agent in the center from evaporating too quickly. This allows the aerogel particles to penetrate the flames and reach the center of the fire source. The aerogel particles adhere to the surface of the burning material, while the extinguishing agent in the center continues to evaporate and cool down, directly reducing the temperature at the center of the fire source. This effectively overcomes the shortcomings of traditional pure liquid extinguishing agents, which often evaporate completely by the time they reach the center of the fire source, and are often difficult to spray into the center of the fire source when the fire is very large.

[0026] 3. By modifying and coating the surface of the aerogel, the difficulty of adding the aerogel to the water-based fire extinguishing agent is reduced, the preparation process is simplified, and the prepared aerogel fire extinguishing liquid has better performance and is more stable. Detailed Implementation

[0027] The principles and features of the present invention are described below. The embodiments given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0028] Prepare aerogel nitrogen-based flame retardants according to the following specific steps:

[0029] 1) Prepare an aqueous dispersion of nitrogen-based flame retardant (urea, U111897, Shanghai Aladdin Biochemical Technology Co., Ltd.), adjust the pH value to neutral, and the solid content in the aqueous dispersion is 6%;

[0030] 2) Water glass is used as raw material. After desalination, an aqueous silica sol is obtained as an aerogel precursor. The pH value can be adjusted to make it stable for storage. The solid content of silica is 15%.

[0031] 3) Mix the aqueous dispersion of the flame retardant obtained in step 1) and the aqueous silica sol obtained in step 2) at a weight ratio of 0.5:1, stir evenly, maintain the temperature at 20°C, and stir and disperse for 45 minutes to obtain a uniformly mixed silica aerogel precursor containing flame retardant.

[0032] 4) Adjust the pH of the silica aerogel precursor containing flame retardant obtained in step 3) to between 4 and 6, and place it in a water bath at 55°C for gelation and aging for 2 hours.

[0033] 5) Activate the gel obtained in step 4) in a hydrochloric acid or sulfuric acid solution with a mass concentration of more than 15%, and make the mass concentration of acid in the gel greater than 10%.

[0034] 6) Take out the activated gel from step 5), immerse the gel in a liquid of hexamethyldisiloxane, seal and heat to 60°C for modification treatment. To improve the modification efficiency, a small amount of trimethylchlorosilane can be added.

[0035] 7) After modification, the product is dried at the following temperatures: 70°C for 2 hours, 95°C for 3 hours, 110°C for 4 hours, to obtain the aerogel flame retardant.

[0036] Using the above preparation method, and by selecting phosphorus-based flame retardants (pentaerythritol phosphate, H138950, Shanghai Aladdin Biochemical Technology Co., Ltd.), nitrogen-phosphorus composite flame retardants (Dingxin Polymer FRG-1530), and no flame retardant, respectively, aerogel phosphorus-based flame retardants, aerogel nitrogen-phosphorus composite flame retardants, and aerogels were prepared.

[0037] Then, using nitrogen-based flame retardants, phosphorus-based flame retardants, aerogels, aerogel nitrogen-based flame retardants, aerogel phosphorus-based flame retardants, and aerogel nitrogen-phosphorus composite flame retardants as flame retardant components, aerogel water-based fire extinguishing agents according to the examples in the table below were prepared, and the following properties were measured respectively:

[0038] Methods for determining extinguishing time and whether reignition has occurred:

[0039] 600 mL of gasoline was poured into a 300*300*100 mm ignition pan. Above the pan were neatly stacked wooden strips on a metal support. The wooden strips had a square cross-section with sides of 39 mm ± 1 mm and a length of 400 mm, arranged in nine layers of five strips each. After igniting and burning the gasoline completely, the ignition pan was removed from under the stack of wood. The stack was allowed to burn freely for two minutes. Then, the extinguishing agents prepared in the following examples were used to conduct spray extinguishing experiments, and the extinguishing time and whether reignition occurred were recorded. The results are shown in Table 1.

[0040] Table 1

[0041]

[0042] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing an aerogel flame retardant, characterized in that, The specific steps are as follows: 1) Prepare an aqueous dispersion of the flame retardant, adjust the pH to neutral, and ensure the solid content in the aqueous dispersion is 2-10%; 2) Water glass is used as raw material, and after desalination, an aqueous silica sol is obtained as an aerogel precursor, wherein the solid content of silica is 10-20%; 3) Mix the aqueous dispersion of the flame retardant obtained in step 1) and the aqueous silica sol obtained in step 2) at a weight ratio of (0.5-1):1, stir evenly, maintain the temperature at 15-25℃, and stir and disperse for 30-60 minutes to obtain a uniformly mixed silica aerogel precursor containing flame retardant. 4) Adjust the pH of the silica aerogel precursor containing flame retardant obtained in step 3) to between 4 and 6, and place it in a water bath environment at 50 to 60°C for gelation and aging for 1 to 3 hours. 5) Activate the gel obtained in step 4) in a hydrochloric acid or sulfuric acid solution with a mass concentration of more than 15%, and make the mass concentration of acid in the gel greater than 10%. 6) Take out the activated gel from step 5), immerse the gel in a liquid hexamethyldisiloxane, seal and heat to 55-65°C for modification treatment; 7) After modification, the aerogel flame retardant is dried at 65-75°C for 1.5-2.5 hours, at 90-100°C for 2.5-3.5 hours, and at 105-115°C for 3.5-5.5 hours to obtain the aerogel flame retardant. The flame retardant is urea, pentaerythritol phosphate, and Dingxin Polymer FRG-1530.

2. An aerogel flame retardant prepared by the preparation method according to claim 1.

3. An aerogel-based water-based fire extinguishing agent, characterized in that, The product comprises the following components in weight percentages: 5-40 wt% of the aerogel flame retardant as described in claim 2; 0.1-1 wt% of the dispersant; 0-0.5 wt% of the thixotropic agent; 0-1 wt% of the stabilizer; 0.5-5 wt% of the emulsifier; and 52.5-94.4 wt% of water.

4. The aerogel-based water-based fire extinguishing agent according to claim 3, characterized in that: The dispersant is selected from Dow ACUMER 445N, ACUMER 9300, 2500, DISPARON AQ-320, DISPARON AQ-330, or K-SPERSE A503.

5. The aerogel-based water-based fire extinguishing agent according to claim 3, characterized in that: The thixotropic agent is selected from methylcellulose, hydroxypropyl methylcellulose, hydroxyethylcellulose, or carboxymethylcellulose.

6. The aerogel-based water-based fire extinguishing agent according to claim 3, characterized in that: The stabilizer is selected from carbomer, sodium alginate, or sodium polyacrylate.

7. The aerogel-based water-based fire extinguishing agent according to any one of claims 3 to 6, characterized in that: The emulsifier is selected from bentonite, kaolin, montmorillonite or diatomaceous earth.

8. A method for preparing an aerogel-based water-based fire extinguishing agent according to any one of claims 3 to 7, characterized in that, Includes the following steps: The components are mixed according to the formula to obtain the aerogel water-based fire extinguishing agent.

9. The application of an aerogel-based water-based fire extinguishing agent according to any one of claims 3 to 7, characterized in that: Used to manufacture water-based fire extinguishers.

Images