Highly stable environment-friendly fluorine-free foam extinguishing agent and preparation method thereof

Abstract

This invention relates to the field of fire extinguishing agent technology, and discloses a highly stable, environmentally friendly, fluorine-free foam fire extinguishing agent and its preparation method. The fire extinguishing agent comprises the following components by mass percentage: 12-15% foaming agent system, 0.6-1.0% foam stabilizer, 5-20% oil-blocking crosslinking agent, 0.5-2.0% spreading and reinforcing agent, 3-5% environmental adaptant, 3-5% solvent, 0.5-1.0% pH adjuster, and the balance being water. The oil-blocking crosslinking agent includes an oil-coating agent, a nano-dispersion, and an oleophobic crosslinking ester. The oil-coating agent is an aluminum fatty acid composite salt; the nano-dispersion is a long-chain fatty acid alkaline earth metal salt nano-dispersion; and the oleophobic crosslinking ester is a styrene-maleic anhydride copolymer long-chain alkyl ester. This invention achieves high-efficiency fire extinguishing and long-lasting anti-reignition performance by forming a three-dimensional network oil-gas barrier structure through a ternary complex system of oil-blocking crosslinking agents with coordination bridging, under completely fluorine-free conditions.

Description

Technical Field

[0001] This invention relates to the field of fire extinguishing agent technology, specifically to a highly stable, environmentally friendly, fluorine-free foam fire extinguishing agent and its preparation method. Background Technology

[0002] Flammable liquid (Class B) fires are characterized by rapid spread, high explosion risk, and susceptibility to reignition, making them a key target for fire prevention and control in industries such as petrochemicals, energy storage, and marine transportation. Foam extinguishing agents, with their dual extinguishing mechanism of oxygen isolation and cooling, are the mainstream core material for extinguishing these types of fires. Among them, aqueous fluorinated film-forming foam (AFFF) was once widely used due to its high extinguishing efficiency and good resistance to reignition; however, its core component, perfluorinated / polyfluoroalkyl substances (PFAS), has strong bioaccumulation and environmental persistence, and has been strictly restricted and banned by environmental regulations in many countries worldwide. my country has also tightened restrictions on the production and use of related products, making fluorine-free and environmentally friendly foam extinguishing agents an inevitable trend in industry research and development.

[0003] To achieve performance substitution for fluorine-free systems, existing technologies mainly employ four types of technical solutions: One approach is to replace silicone surfactants. To reduce surface tension and improve the spreading speed and film stability of the foamed oil, existing technologies use silicone surfactants to replace fluorocarbon surfactants. However, the flame root temperature of hydrocarbon combustion reaches 80-100℃. At this temperature, the activity of silicone surfactants decreases significantly and they are easily hydrolyzed, making them ineffective at blocking hydrocarbon vapors. While they show good results in small-scale laboratory experiments, they cannot replace fluorinated AFFFs in large-scale model experiments and real-world applications.

[0004] The second approach involves thickener and nanomaterial modification. To enhance foam stability, existing technologies add thickeners and nanomaterials to the synthetic foam system, achieving foam stability by increasing the system viscosity and supporting the liquid film structure. However, temperature changes can easily cause nanoparticles to aggregate, precipitate, and fail. High thickener dosages can also lead to excessively high system viscosity, resulting in insufficient siphoning of the original liquid and uneven mixing in pipelines, making it unsuitable for conventional fire-fighting equipment.

[0005] Thirdly, there is the thermally responsive weak gel solution. To achieve long-term sealing of hydrocarbon vapors and improve resistance to reignition, existing technologies have developed systems that can rapidly form gel foams from room-temperature liquids upon contact with high-temperature fuels. However, this solution requires extremely high surfactant levels, making it impossible to prepare industry-standard 3% or 6% products. Furthermore, the gelation process is easily affected by the environment, leading to premature deterioration during storage and the inability to gel promptly during firefighting, thus failing to meet practical application requirements.

[0006] Fourthly, there is the three-phase foam solution. To enhance the oxygen barrier and vapor barrier effects, existing technologies have developed a solid-liquid-gas three-phase solidified foam system, which requires two-component storage and dual-pump mixing for use. However, this solution cannot be adapted to existing conventional fire-fighting equipment and requires specialized devices, making it unsuitable for widespread application and only applicable to niche scenarios such as spontaneous combustion prevention in coal mines.

[0007] Therefore, there is an urgent need to develop a highly stable, environmentally friendly, fluorine-free foam extinguishing agent that has excellent fire performance and is compatible with existing conventional fire-fighting equipment. Summary of the Invention

[0008] The purpose of this invention is to provide a highly stable and environmentally friendly fluorine-free foam fire extinguishing agent that, while achieving fluorine-free environmental protection, also takes into account both high-efficiency fire extinguishing and long-term anti-reignition performance, in order to solve the technical problems of performance imbalance, poor storage stability and limited scene adaptability of existing fluorine-free foam fire extinguishing agents.

[0009] To achieve the above objectives, the present invention provides the following technical solution: A highly stable, environmentally friendly, fluorine-free foam fire extinguishing agent comprises the following components by weight percentage: 12-15% foaming agent system, 0.6-1.0% foam stabilizer, 5-20% oil-blocking crosslinking agent, 0.5-2.0% spreading and reinforcing agent, 3-5% environmental adaptant, 3-5% solvent, 0.5-1.0% pH adjuster, and the balance being water; The oil-blocking crosslinking agent includes an oil-coagulating agent, a nano-dispersion, and an oleophobic crosslinking ester; the oil-coagulating agent is an aluminum complex salt of fatty acids; the nano-dispersion is a long-chain fatty acid alkaline earth metal salt nano-dispersion; and the oleophobic crosslinking ester is a styrene-maleic anhydride copolymer long-chain alkyl ester.

[0010] Preferably, the oil-gelling agent is selected from one or more of potassium aluminum isooctanoate, sodium aluminum isooctanoate, potassium aluminum laurate, sodium aluminum laurate, potassium aluminum palmitate, sodium aluminum palmitate, potassium aluminum oleate, sodium aluminum oleate, potassium aluminum linoleate, and sodium aluminum linoleate; the nano-dispersion is selected from one or more of calcium stearate, magnesium stearate, calcium behenate, and magnesium behenate; and the oleophobic crosslinking ester is selected from one or more of poly(styrene-maleic anhydride) dodecyl, poly(styrene-maleic anhydride) tetradecyl, poly(styrene-maleic anhydride) hexadecyl, and poly(styrene-maleic anhydride) octadecyl.

[0011] To address the core shortcomings of existing fluorine-free foam fire extinguishing agents, such as weak oil vapor barrier capabilities, poor resistance to reignition, and easy structural failure at high temperatures, this invention designs an oil-blocking crosslinking system composed of an oil-coating agent, a nano-dispersion, and an oleophobic crosslinking ester. Combined with an environmental adaptant, a molecular-level three-dimensional network oil vapor barrier structure is constructed through coordination bridging. This achieves long-lasting hydrocarbon vapor barrier effects at high temperatures while completely avoiding the use of fluorine-containing components, balancing rapid fire extinguishing with long-lasting resistance to reignition, and simultaneously improving the system's salt resistance and storage stability.

[0012] Specifically, the oil-condensing agent can quickly capture hydrocarbon fuel molecules that come into contact with the condensation system, forming a dense oil-condensing isolation layer at the interface between the foam and the oil surface. This prevents hydrocarbon fuels from penetrating and diffusing into the foam layer, while simultaneously blocking the evaporation path of liquid hydrocarbons into the gas phase, thus suppressing the risk of reignition at the interface.

[0013] The polyvalent alkaline earth metal ions in the nano-dispersion can coordinate and bridge with polar groups such as ester groups, hydroxyl groups, and acid anhydrides in the molecular structure of environmental adaptants and oleophobic crosslinked esters, crosslinking the original linear molecules to form a three-dimensional network structure. This network structure can form a stable spatial support skeleton in the foam liquid film, greatly improving the high-temperature stability and mechanical strength of the foam liquid film, avoiding rapid rupture and failure of the liquid film at high temperatures. At the same time, it can form multi-level oil and gas barrier channels in the foam layer, greatly extending the permeation path of hydrocarbon vapors and achieving long-term oxygen and vapor barrier.

[0014] The long-chain alkyl side chains of oleophobic crosslinked esters can be oriented at the oil-gas interface to form a strong oleophobic and impermeable barrier, which greatly reduces the interfacial tension between the foam system and hydrocarbon fuels and prevents the foam from being defoamed and rendered ineffective by hydrocarbon fuels. At the same time, the main chain structure of the oleophobic crosslinked ester can participate in coordination bridging and become a core component of the three-dimensional network structure, further enhancing the compactness and stability of the network structure, filling the tiny gaps in the condensed oil layer, and improving the system's resistance to high temperatures and impermeability.

[0015] The synergistic effect of the interfacial oil-gathering isolation of the oil-gelling agent, the spatial framework support of the nano-dispersion, and the interfacial anti-seepage barrier of the oleophobic crosslinked ester, combined with the three-dimensional network structure formed by coordination bridging, constructs a triple oil and gas barrier system of interfacial oil-gathering, intra-membrane vapor barrier, and overall anti-seepage, achieving a long-lasting anti-reignition effect at high temperatures.

[0016] Preferably, the foaming agent system is a mixture of amphoteric surfactants and long-chain alkyl quaternary ammonium salt cationic surfactants in a mass ratio of 5 to 10:1.

[0017] More preferably, the amphoteric surfactant is selected from one or more of lauramide propylamine oxide, cocamidopropylamine oxide, dodecyl dimethylamine oxide, tetradecyl dimethylamine oxide, and hexadecyl dimethylamine oxide; the long-chain alkyl quaternary ammonium salt cationic surfactant is selected from one or more of hexadecyl trimethylammonium chloride, octadecyl trimethylammonium chloride, hexadecyl trimethyl ammonium sulfate, and octadecyl trimethyl ammonium sulfate.

[0018] Amphoteric surfactants and amine oxide surfactants, as the main foaming agents, can reduce the surface tension of the system, improve the foaming ratio and foam fineness. Long-chain alkyl quaternary ammonium salt cationic surfactants can form a directional adsorption layer on the surface of the foam liquid film, improve the salt resistance and stability of the liquid film, avoid the decay of the foaming performance of the system after seawater dilution, and at the same time help to enhance the antibacterial and antiseptic capabilities of the system and extend the product storage period.

[0019] Preferably, the spreading enhancer is a mixture of acetylenic diol nonionic surfactant and sulfonate anionic surfactant in a mass ratio of 1:0.8~1.2.

[0020] More preferably, the acetylenic diol nonionic surfactant is selected from one or more mixtures of dimethyloctylenic diol and tetramethyldecylenic diol; the sulfonate anionic surfactant is selected from one or more mixtures of sodium dodecyl diphenyl ether disulfonate and sodium lauryl imidazoline sulfonate.

[0021] The dihydroxyl groups on the alkynyldiol nonionic surfactant molecules can form a 1:1 strong intermolecular association structure with the disulfonic acid group on the sodium dodecyl diphenyl ether disulfonate molecule or the ammonium and sulfonic acid groups on the sodium lauryl imidazoline sulfonate molecule. At the same time, the triple alkynyl group in the alkynyldiol molecule structure can significantly improve the molecular rigidity of the system, greatly restrict the curling deformation of the surfactant molecule in aqueous solution, thereby ensuring the stability of the above association structure and providing a stable structural basis for the system performance.

[0022] Specifically, the spreading enhancer formed by this compound achieves synergistic effects through the complementary properties of the two types of surfactants, which can further reduce the oil-water interfacial tension of the system and significantly improve the spreading speed of foam on the surface of high-temperature hydrocarbon fuels: on the one hand, the acetylenic diol nonionic surfactant, with its compact molecular structure, can quickly migrate to the gas-liquid interface and has extremely low dynamic surface tension, achieving rapid wetting of the high-temperature oil surface. At the same time, its molecular structure can provide abundant hydrogen bonding, giving the foam liquid film excellent dynamic repair capabilities; on the other hand, the sulfonate anionic surfactant can form a strong double-layer repulsion force at the liquid film interface, significantly improving the viscoelasticity of the liquid film and effectively preventing the liquid film from rapidly shrinking and rupturing under high-temperature conditions.

[0023] Preferably, the environmental adaptant is a mixture of octadecyl acrylate-acrylic acid copolymer, glyceryl monooleate borate and aluminum polyacrylate in a mass ratio of 2.4~3.5:0.7~1.2:4.5~7.2.

[0024] Specifically, the octadecyl acrylate-acrylic acid copolymer is a polymer of octadecyl acrylate and acrylic acid in a molar ratio of 1:10~15, with a number average molecular weight of 100,000-300,000.

[0025] Preferably, the foam stabilizer is selected from one or more of the following: cocoyl monoethanolamine, cocoyl diethanolamine, sodium secondary alkyl sulfonate, pectin, sodium alginate, hydroxypropyl cellulose, carboxymethyl cellulose, modified cyclodextrin, polyoxypropylene-polyoxyethylene block polymer, and pyrrolidone copolymer.

[0026] Specifically, the modified cyclodextrin is hydroxypropyl-β-cyclodextrin; the polyoxypropylene-polyoxyethylene block polymer is an EO-PO-EO type triblock polymer, wherein the molar ratio of EO:PO:EO is 1:(0.5~4):(0.8~1.2), and the number average molecular weight is 6400-15000; the pyrrolidone copolymer is a vinylpyrrolidone and vinyl acetate copolymer, wherein the molar ratio of vinylpyrrolidone and vinyl acetate is 1:0.3~0.6, and the number average molecular weight is 30000-150000.

[0027] Preferably, the solvent is a short-chain alcohol ether and / or a short-chain low-carbon alcohol; more preferably, the short-chain alcohol ether is selected from one or more of diethylene glycol butyl ether, ethylene glycol butyl ether, and ethylene glycol tert-butyl ether; and the short-chain low-carbon alcohol is selected from one or more of ethylene glycol, propylene glycol, ethanol, and isopropanol.

[0028] Short-chain alcohol ethers can form hydrogen bonds with the nitrogen atoms on surfactant molecules through their hydroxyl and ether bonds. Furthermore, their smaller hydrophilic head groups allow them to uniformly embed into the gaps between other surfactant molecules at the gas-liquid interface, filling interfacial voids and optimizing the arrangement and adsorption strength of surfactant molecules on the foam film. This significantly enhances the density and structural strength of the hydrophobic layer at the liquid film interface. This unique arrangement optimization effect effectively reduces the overall addition amount of the main foaming agent and foam stabilizer without affecting the foaming and stabilizing performance of the system. Simultaneously, it significantly reduces the degree of emulsification of fuel oil by the extinguishing agent system, avoiding foam defoaming failure and reduced anti-reignition performance caused by fuel oil emulsification.

[0029] Short-chain low-carbon alcohols are mainly used as antifreeze agents in this system, which can effectively reduce the freezing point of the fire extinguishing agent system, ensure the storage stability and performance of the product in low-temperature environments, and at the same time help improve the dispersion and solubility of organic functional components in the aqueous phase.

[0030] Preferably, the pH adjuster includes an acidic pH adjuster and an alkaline pH adjuster; the acidic pH adjuster is selected from one or more of citric acid, tartaric acid, and salicylic acid; the alkaline pH adjuster is selected from one or more of bicarbonate, triethanolamine, diethanolamine, and triethylamine.

[0031] This invention uses a combination of weak acid and weak base as a pH adjuster, which can stabilize the pH value of the system between 7.2 and 7.8, providing a stable environment for each functional component to function.

[0032] This invention also provides a method for preparing the above-mentioned highly stable and environmentally friendly fluorine-free foam fire extinguishing agent, comprising the following steps: S1 Add environmental adaptant and oil-inhibiting crosslinking agent to water according to the formula ratio, disperse at high speed at 3000r / min for 25-35min, and let stand for crosslinking for 2-4h to obtain pre-crosslinked dispersion; S2. Heat the pre-crosslinked dispersion to 45-55℃, add the foaming agent system and foam stabilizer in sequence according to the formula, keep warm and stir until completely dissolved, add pH adjuster to adjust the pH value of the system to 7.2-7.8, cool down to below 40℃; then add spreading enhancer and solvent according to the formula, add the remaining water, stir evenly, and filter through a 200-mesh filter to obtain the high-stability environmentally friendly fluorine-free foam fire extinguishing agent.

[0033] Compared with the prior art, the present invention has the following advantages: 1. This invention constructs a triple protection system of interfacial oil-blocking crosslinking agent ternary compound system, combined with a three-dimensional network oil-gas barrier structure formed by coordination bridging, which can maintain stable oil-gas barrier capability at high temperature. At the same time, it achieves rapid oil surface spreading through spreading enhancer, taking into account both high efficiency fire extinguishing and long-term anti-reignition performance.

[0034] 2. This invention employs a fluorine-free design, completely eliminating PFAS (per- and polyfluoroalkyl substances), fully complying with the updated proposal issued by the European Chemicals Agency (ECHA) on August 20, 2025, regarding the restriction of PFAS under the EU Chemicals Regulation REACH. It avoids the accumulation of persistent organic pollutants, with a biodegradation rate >90% (28 days). Furthermore, in terms of ecological safety, all components of this fire extinguishing agent are low-toxicity substances: acute oral toxicity LD50. 50 >5000 mg / kg, with no significant toxicity to aquatic organisms. Attached Figure Description

[0035] Figure 1 The images show a comparison of scanning electron microscope (SEM) images of Embodiment 1 and Comparative Example 3 of the present invention. Figure 2 Comparative atomic force microscope (AFM) images of Example 1 and Comparative Example 3 of this invention; Figure 3 This is a comparison image of atomic force microscopy (AFM) used in Example 1 and Comparative Example 4 of the present invention. Detailed Implementation

[0036] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with applications. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims of the present invention.

[0037] Example 1 This embodiment provides a highly stable, environmentally friendly, fluorine-free foam fire extinguishing agent. The components, by mass percentage, are as follows: The foaming agent system (cocamidopropyl betaine + hexadecyltrimethylammonium chloride) 15%; foam stabilizer (pectin) 0.9%; oil-blocking crosslinking agent (potassium aluminum laurate + calcium stearate + poly(styrene-maleic anhydride) hexadecyl acetate) 20%; spreading and reinforcing agent (tetramethyldecynyl glycol + sodium dodecyl diphenyl ether disulfonate) 2.0%; environmental adaptant 4.0%; solvent 3.0%; pH adjuster 1.0%; water 54.1%. The environmental adaptant, solvent, and pH adjuster are used as auxiliary materials, and the following fixed compounding ratios and addition amounts are adopted: The environmental adaptant is composed of octadecyl acrylate-acrylic acid copolymer (commercially available octadecyl acrylate-acrylic acid linear copolymer, which can be prepared by conventional free radical polymerization or obtained commercially) obtained by polymerizing octadecyl acrylate and acrylic acid in a molar ratio of 1:10, glyceryl monooleate borate, and aluminum polyacrylate in a mass ratio of 3:1:6, and the addition amount is 4.0%; the solvent used is diethylene glycol butyl ether, and the addition amount is 3.0%; the pH adjuster is composed of 30% citric acid aqueous solution and 30% sodium bicarbonate aqueous solution in a mass ratio of 3:1, and the addition amount is 1.0%, and the pH buffer range of the system is 7.2-7.8.

[0038] The preparation method of a highly stable, environmentally friendly, fluorine-free foam fire extinguishing agent provided in this embodiment includes the following steps: S1: First, weigh 40g of environmental adaptant (12g of octadecyl acrylate-acrylic acid copolymer, 4g of glyceryl monooleate borate, and 24g of aluminum polyacrylate) and add them to a disperser in sequence. Disperse at 3000r / min for 30min. Then, add 200g of oil-inhibiting crosslinking agent (66.66g of potassium aluminum laurylate, 66.66g of calcium stearate, and 66.68g of poly(styrene-maleic anhydride) hexadecyl ester) in sequence and continue to disperse at 3000r / min for more than 3 hours. After that, add 30g of diethylene glycol butyl ether to dilute and stir evenly for later use.

[0039] S2: Add industrial soft water to the reactor, start stirring and heat to about 50°C; then weigh 9g of pectin and 150g of foaming agent system (75g of cocamidopropyl betaine and 75g of hexadecyltrimethylammonium chloride), add them to the reactor in sequence, stir at 30-45r / min until completely uniform and then stop heating; then add pH adjuster to adjust the pH to 7.2-7.8; The pre-dispersed liquid prepared in step S1 is then slowly added to the reactor, and the disperser is repeatedly rinsed with industrial soft water. All the rinsing liquid is then added to the reactor. After the temperature drops below 40°C, 20g of spreading and reinforcing agent (5g of tetramethyldecynyl diol and 5g of sodium dodecyl diphenyl ether disulfonate) is slowly added. After stirring evenly, the mixture is filtered and discharged to obtain a total of 1000g of fire extinguishing agent.

[0040] Example 2-16 Examples 2-16 provide a highly stable, environmentally friendly, fluorine-free foam fire extinguishing agent prepared based on the preparation method of Example 1. The difference between the two examples is that the types and / or amounts of raw materials for the foaming agent system, foam stabilizer, oil-blocking crosslinking agent, and spreading and reinforcing agent are different. To ensure that the total mass of the fire extinguishing agent is constant at 1000g, the amount of industrial soft water added is adjusted accordingly. The raw material composition, amount added, and all preparation steps of the other auxiliary components are the same as those in Example 1. The specific differences are shown in Table 1.

[0041] Table 1

[0042] Table 1 (continued)

[0043] Comparative Example 1 Comparative Example 1 provides a highly stable and environmentally friendly fluorine-free foam fire extinguishing agent prepared by the preparation method of Example 1. The difference between Comparative Example 1 and Example 2 is that no foaming agent system is added, while the other raw materials, dosages and preparation steps are the same as those in Example 1.

[0044] Comparative Example 2 Comparative Example 2 provides a highly stable, environmentally friendly, fluorine-free foam fire extinguishing agent prepared based on the preparation method of Example 1. The difference between Comparative Example 2 and Example 1 is that no foam stabilizer is added, while the other raw materials, dosages, and preparation steps are the same as in Example 1.

[0045] Comparative Example 3 Comparative Example 3 provides a highly stable, environmentally friendly, fluorine-free foam fire extinguishing agent prepared based on the preparation method of Example 1. The difference between it and Example 1 is that no oil-blocking crosslinking agent is added, while the other raw materials, dosages, and preparation steps are the same as in Example 1.

[0046] A comparison of scanning electron microscope (SEM) images of Example 1 and Comparative Example 3 is shown in the figure below. Figure 1 As shown, its magnification is 5000x and the scale bar is 20μm. A comparison of atomic force microscopy (AFM) images of Example 1 and Comparative Example 3 is shown below. Figure 2 As shown in the figure, both the horizontal and vertical scales are 10 μm, and the field of view is 10 μm × 10 μm. It can be seen that the solution of Comparative Example 3 exhibits a relatively loose structure with virtually no connection between the structures; while the solution of Example 1 exhibits obvious cross-linking and three-dimensional network structure.

[0047] Comparative Example 4 Comparative Example 4 provides a highly stable, environmentally friendly, fluorine-free foam fire extinguishing agent prepared based on the preparation method of Example 1. The difference between it and Example 1 is that no spreading and reinforcing agent is added, while the other raw materials, dosages, and preparation steps are the same as in Example 1.

[0048] Comparison of atomic force microscopy (AFM) images of Example 1 and Comparative Example 4 are shown below. Figure 3 As shown in the figure, both the horizontal and vertical scales are 10, and the field of view is 10μm×10μm. This indicates that in the solution of Comparative Example 4, there are some instances of uneven liquid film thickness between the structures. After adding the spreading enhancer, the liquid film thickness significantly increases, and the uniformity is improved.

[0049] Comparative Example 5 Comparative Example 5 provides a highly stable and environmentally friendly fluorine-free foam fire extinguishing agent prepared based on the preparation method of Example 1. The difference between it and Example 1 is that the foaming agent system of Example 1 is replaced with sodium dodecyl sulfate, a single anionic foaming agent commonly used in the prior art. The other raw materials, dosages and preparation steps are the same as those of Example 1.

[0050] Comparative Example 6 Comparative Example 6 provides a commercially available imported fluorine-free foam fire extinguishing agent, specifically the HP-3% fluorine-free foam fire extinguishing agent manufactured by INCENDIN.

[0051] Comparative Example 7 Comparative Example 7 provides a commonly used domestically produced fluorine-free foam fire extinguishing agent (based on 100% of the total mass of the fire extinguishing agent, the components and contents are as follows: sodium lauryl polyoxyethylene ether sulfate 10.0%, sodium dodecylbenzene sulfonate 3.0%, sodium α-alkenyl sulfonate 5.0%, carboxylated polyether modified organosilicon surfactant 1.5%, cocamidopropyl betaine 2.0%, xanthan gum 0.25%, sodium alginate 0.15%, urea 3.0%, ammonium polyphosphate (water-soluble) 1.5%, disodium ethylenediaminetetraacetate 0.1%, ethylene glycol 6.0%, sodium benzoate 0.1%, deionized water 67.4%).

[0052] Experimental Example 1 To evaluate the practical application performance of the highly stable, environmentally friendly, fluorine-free foam fire extinguishing agent prepared in this invention in fresh water, 3L of the concentrated solutions from Examples 1-16 and Comparative Examples 1-7 were mixed with 47L of tap water to prepare approximately 50L of foam fire extinguishing agent mixtures with a concentration of 6%. Subsequently, the foam physical properties of each mixture in fresh water, as well as its fire extinguishing and anti-burning properties using n-heptane as fuel, were measured according to the methods specified in the national standard GB / T15308-2025 Foam Fire Extinguishing Agents.

[0053] This experiment mainly involves the following key test indicators and equipment, the specific meanings of which are as follows: First, foam performance testing is primarily simulated using two different foaming devices. The "5L / min foam gun" simulates a low-expansion foam generator, used to test the foaming capacity of the extinguishing agent at low flow rates. The "standard foam gun" represents foam generating equipment specified by national standards, used to determine the foam state under normal operating conditions. The expansion ratio refers to the ratio of the volume of foam generated to the volume of foam solution required to generate that foam. For example, an expansion ratio of 8 means that 1 liter of solution can produce 8 liters of foam. This value reflects the foam's expansion capacity and coverage efficiency. The 25% outburst time refers to the time required for 25% of the liquid contained in the foam to seep out after generation. The longer the outburst time, the stronger the foam's water-locking ability, the more durable the coverage layer, and the less prone it is to breakage.

[0054] Secondly, the fire extinguishing and fire resistance tests were conducted on fire sources of varying sizes. (0.25m) 2 A small-scale oil pan fire test is used for preliminary screening and rapid evaluation of the extinguishing efficiency of fire extinguishing agents. A standard oil pan fire test, on the other hand, refers to a large-scale oil pan fire test that conforms to national standards, simulating more realistic fire scenarios and imposing more stringent requirements on the extinguishing agent. Extinguishing time refers to the time required from the start of foam spraying to the complete extinguishing of the flame; a shorter time indicates a faster extinguishing speed. Resistant burning time refers to the duration after the flame is extinguished, during which the foam covering layer can resist the re-ignition (pre-ignition) of fuel vapors; a longer time indicates better thermal and oxygen-barrier performance of the foam layer and a stronger ability to prevent reignition.

[0055] The specific data obtained from the experiment are shown in Table 2.

[0056] Table 2

[0057] As shown in Table 2, the foam extinguishing agents prepared in Examples 1-16 exhibited excellent comprehensive performance in terms of expansion ratio, 25% separation time, extinguishing time, and fire resistance time. Among them, Examples 1 and 3-5 showed the best extinguishing time and fire resistance time, meeting the technical requirements of Class 1A in the national standard GB / T15308-2025 Foam Extinguishing Agents. The fire resistance time of the remaining examples also reached more than 7 minutes, indicating that the formed foam covering layer has stable heat insulation and oxygen barrier properties.

[0058] Compared to Examples 1-11, Examples 12-16 showed a decrease in both the foaming ratio and the 25% separation time. Specifically, the foaming ratio under a standard foam gun decreased to 6.59-6.97, and the 25% separation time decreased to 6'13"-7'37". Correspondingly, the extinguishing time and fire-resistant time of Examples 12-16 were also extended and shortened, respectively, with the fire-resistant time ranging from 7'39" to 11'31". These data indicate that changes in the amount of foaming agent affected both the physical properties of the foam and its fire-extinguishing performance.

[0059] The expansion ratio of Comparative Example 1 was significantly lower than that of the Example 1, with an expansion ratio of only 5.41 under a 5L / min foam gun and only 4.03 under a standard foam gun. The fire extinguishing test results showed that Comparative Example 1, at a depth of 0.25m... 2 The flames could not be extinguished in either the oil pan or the standard oil pan test. This result indicates that foaming agent components are necessary for effective fire extinguishing, and insufficient foaming ratio makes it difficult to form an effective foam covering layer to isolate oxygen.

[0060] Comparative Example 2, without the addition of a foam stabilizer, had a foaming ratio similar to that of the Examples (8.06 at a 5L / min foam gun), but its 25% separation time was significantly shorter than that of the Examples, only 3'52" at a standard foam gun, while Examples 1-11 were 7'41"-9'33". Regarding extinguishing time, Comparative Example 2 showed little difference from the Examples, but its fire resistance time was significantly reduced, only 2'44" at a standard oil pan, while Examples 1-11 were 9'11"-11'42". These results indicate that the foam stabilizer primarily affects foam stability, has a relatively small impact on extinguishing time, but has a significant effect on the durability and reignition resistance of the foam coating.

[0061] In Comparative Example 3, no oil-blocking crosslinking agent was added. During fire extinguishing, the fire mainly relied on the strong coverage of the foam, resulting in a slightly slower extinguishing speed compared to the Example. However, during the anti-burning stage, due to the absence of the oil-blocking crosslinking agent, the foam layer was deficient in blocking fuel oil vapor, causing the flame to continue burning on the foam surface, resulting in a very short anti-burning time (only 2'41" for the standard oil pan). This result indicates that the oil-blocking crosslinking agent plays a role in maintaining the barrier performance of the foam covering layer. When absent, the foam layer is unable to effectively block fuel oil vapor, leading to a decrease in the anti-reignition performance.

[0062] In Comparative Example 4, which did not contain a spreading enhancer, the foam performance was excellent during the performance evaluation (both expansion ratio and liquid separation time were outstanding). However, during fire extinguishing, the foam spread very slowly on the fuel oil surface, and the foam at the edges defoamed quickly. Within the specified foam supply time, it was unable to completely cover the entire fuel oil surface, resulting in significant edge fire and ultimately preventing extinguishing the fire. This demonstrates that the spreading enhancer component in the extinguishing agent system can significantly accelerate the foam spreading speed on the fuel oil surface, ensuring rapid flame extinguishing within the effective foam supply time.

[0063] Comparative Example 5 uses a commonly used anionic foaming agent in the prior art, which at 0.25m 2 The flames could not be extinguished in both the oil pan and standard oil pan tests. During the testing process, it was found that the anionic foaming agent commonly used in this existing technology has a strong emulsifying effect on fuel oil. This easily leads to reignition of the flame on the surface of the foam layer during fire extinguishing, preventing the formation of a stable oxygen-barrier and heat-insulating covering layer, ultimately resulting in fire extinguishing failure. This is because the strong oil-phase emulsifying effect of sodium dodecyl sulfate emulsifies the fuel into suspended oil droplets, which are carried to the surface of the foam layer, triggering a fatal surface flashover and reignition; furthermore, as a strong anionic surfactant, sodium dodecyl sulfate reacts with the Ca released by the oil-inhibiting crosslinking agent in this formulation. 2+ Al 3+ The quantitative complexation of polyvalent metal ions forms insoluble precipitates, which irreversibly consume the foaming active components. At the same time, the foam liquid film formed has poor viscoelasticity and no hydrogen bond synergistic effect with the pectin foam stabilizer, making it impossible to construct a stable oxygen-barrier and heat-insulating covering layer. This result proves that only by screening a composite foaming agent system that is highly compatible with the ternary oil-resistant crosslinking system of this invention and has synergistic foam stabilization and oil-resistant solvent resistance can a highly efficient and stable fire extinguishing effect be achieved.

[0064] While Comparative Example 6 exhibits superior foaming and application performance, its sample viscosity is high. When preparing the working solution, the sample needs to be mixed with tap water and vigorously stirred for approximately 30 minutes to achieve uniform dispersion. However, in actual field applications, the product and tap water can only mix through flow within a limited length of pipe, making it difficult to achieve thorough mixing. This prevents the product from fully realizing its potential and significantly limits its practical engineering applications.

[0065] Comparative Example 7 has a slower fire extinguishing rate and poorer anti-burning performance. In the standard oil pan test, the anti-burning time is only 5 minutes and 32 seconds, which is far inferior to the technical effect of the embodiment of the present invention. This is because the product replaces the fluorocarbon surfactant with the wetting performance and surface tension reduction ability of the silicone surfactant. However, the silicone surfactant has the defect of performance decay at high temperature, which ultimately leads to its poor fire extinguishing and anti-burning performance.

[0066] In summary, the foam fire extinguishing agents prepared in Examples 1-16 of this invention exhibit excellent overall performance. Examples 1 and 3-5 meet the Class 1A technical requirements of GB / T15308-2025, and the amount of foaming agent significantly affects product performance. Comparative Examples 1-5 all resulted in a significant decrease in fire extinguishing or fire resistance performance, verifying the necessity of each component in the formulation of this invention. The commercially available products used in Comparative Examples 6-7 suffer from difficulties in on-site mixing and poor high-temperature performance, thus limiting their application.

[0067] Experiment Example 2 This experimental example aims to verify the physicochemical properties and practical application performance of the foam fire extinguishing agent of the present invention in seawater systems. The specific experimental methods and steps are as follows: Step 1: Prepare artificial seawater according to Clause 6.10.3 of the national standard GB / T15308-2025 "Foam Extinguishing Agents".

[0068] Step 2: Take 3L of each of the samples from Examples 1-16 and Comparative Examples 1-6, and mix them with 47L of the above-mentioned artificial seawater to prepare 50L of foam extinguishing agent working solution.

[0069] Step 3: According to the methods specified in Clauses 6.8 and 6.10 and Appendix A of GB / T15308-2025 "Foam Extinguishing Agents", the foam performance of each foam extinguishing agent working fluid in the seawater system, as well as the extinguishing performance and anti-burning performance with n-heptane as fuel, were determined. The experimental results are shown in Table 3.

[0070] Table 3

[0071] As shown in Table 3, the test data of Examples 1-16 of this invention exhibit excellent performance stability in the seawater system. Example 1 shows a slightly longer anti-burning time in the seawater system compared to the freshwater system, but all performance indicators meet the technical requirements of Class 1A in the national standard GB / T15308-2025 "Foam Extinguishing Agents," indicating that it can still maintain efficient fire extinguishing and anti-burning capabilities in a seawater environment. The key performance indicators of the other examples and comparative examples 1-6 in the seawater system, such as foaming ratio, 25% separation time, fire extinguishing time, and anti-burning time, are basically similar to the test results in the freshwater system, with no significant deterioration. The above experimental results fully demonstrate that the highly stable, environmentally friendly, fluorine-free foam extinguishing agent prepared by this invention possesses excellent seawater resistance. Its performance is not affected by the salt content in the seawater system, and it can stably exert its foam physical properties and fire extinguishing application performance in a seawater environment, making it suitable for fire extinguishing needs in seawater scenarios.

[0072] In contrast, the overall performance of Comparative Example 7 in the seawater system was significantly deteriorated compared to the freshwater system: the foaming ratio decreased slightly, the 25% separation time was significantly shortened, the extinguishing time was prolonged, and the anti-burning performance was greatly reduced. In particular, it could not achieve effective extinguishing in the standard oil pan extinguishing test, which is difficult to meet the actual extinguishing application requirements in seawater scenarios. This further highlights the superiority of the foam extinguishing agent of the present invention in seawater resistance.

Claims

1. A highly stable, environmentally friendly, fluorine-free foam fire extinguishing agent, characterized in that, It includes the following components by weight percentage: foaming agent system 12-15%, foam stabilizer 0.6-1.0%, oil-blocking crosslinking agent 5-20%, spreading and reinforcing agent 0.5-2.0%, environmental compatibility agent 3-5%, solvent 3-5%, pH adjuster 0.5-1.0%, and the balance is water; The oil-blocking crosslinking agent includes an oil-coagulating agent, a nano-dispersion, and an oleophobic crosslinking ester; the oil-coagulating agent is an aluminum complex salt of fatty acids; the nano-dispersion is a long-chain fatty acid alkaline earth metal salt nano-dispersion; and the oleophobic crosslinking ester is a styrene-maleic anhydride copolymer long-chain alkyl ester.

2. The highly stable, environmentally friendly, fluorine-free foam fire extinguishing agent according to claim 1, characterized in that, The oil-gelling agent is selected from one or more of the following: potassium aluminum isooctanoate, sodium aluminum isooctanoate, potassium aluminum laurate, sodium aluminum laurate, potassium aluminum palmitate, sodium aluminum palmitate, potassium aluminum oleate, sodium aluminum oleate, potassium aluminum linoleate, and sodium aluminum linoleate. The nano-dispersion is selected from one or more of calcium stearate, magnesium stearate, calcium behenate, and magnesium behenate. The oleophobic crosslinked ester is selected from one or more of poly(styrene-maleic anhydride) dodecyl ester, poly(styrene-maleic anhydride) tetradecyl ester, poly(styrene-maleic anhydride) hexadecyl ester, and poly(styrene-maleic anhydride) octadecyl ester.

3. The highly stable, environmentally friendly, fluorine-free foam fire extinguishing agent according to claim 1, characterized in that, The foaming agent system is a mixture of amphoteric surfactants and long-chain alkyl quaternary ammonium salt cationic surfactants in a mass ratio of 5~10:

1.

4. The highly stable, environmentally friendly, fluorine-free foam fire extinguishing agent according to claim 3, characterized in that, The amphoteric surfactant is selected from one or more of lauramide propylamine oxide, cocamidopropylamine oxide, dodecyl dimethylamine oxide, tetradecyl dimethylamine oxide, and hexadecyl dimethylamine oxide; The long-chain alkyl quaternary ammonium salt cationic surfactant is selected from one or more of hexadecyltrimethylammonium chloride, octadecyltrimethylammonium chloride, hexadecyltrimethylammonium sulfate, and octadecyltrimethylammonium sulfate.

5. The highly stable, environmentally friendly, fluorine-free foam fire extinguishing agent according to claim 1, characterized in that, The spreading enhancer is a mixture of acetylenic diol nonionic surfactant and sulfonate anionic surfactant in a mass ratio of 1:0.8~1.2; The acetylenic diol nonionic surfactant is selected from one or more of dimethyloctylenic diol and tetramethyldecylenic diol; The sulfonate anionic surfactant is selected from one or more of sodium dodecyl diphenyl ether disulfonate and sodium lauryl imidazoline sulfonate.

6. The highly stable, environmentally friendly, fluorine-free foam fire extinguishing agent according to claim 1, characterized in that, The environmental adaptant is a mixture of octadecyl acrylate-acrylic acid copolymer, glyceryl monooleate borate and aluminum polyacrylate in a mass ratio of 2.4~3.5:0.7~1.2:4.5~7.

2.

7. The highly stable, environmentally friendly, fluorine-free foam fire extinguishing agent according to claim 1, characterized in that, The solvent is a short-chain alcohol ether and / or a short-chain low-chain alcohol; The short-chain alcohol ether is selected from one or more of diethylene glycol butyl ether, ethylene glycol butyl ether, and ethylene glycol tert-butyl ether; The short-chain low-carbon alcohol is selected from one or more of ethylene glycol, propylene glycol, ethanol, and isopropanol.

8. The highly stable, environmentally friendly, fluorine-free foam fire extinguishing agent according to claim 1, characterized in that, The pH adjuster includes at least one of acidic pH adjusters and alkaline pH adjusters; The acidic pH adjuster is selected from one or more of citric acid, salicylic acid, and tartaric acid; The alkaline pH adjuster is selected from one or more of bicarbonate, triethanolamine, diethanolamine, and triethylamine.

9. The highly stable, environmentally friendly, fluorine-free foam fire extinguishing agent according to claim 1, characterized in that, The foam stabilizer is selected from one or more of the following: cocoyl monoethanolamine, cocoyl diethanolamine, sodium secondary alkyl sulfonate, pectin, sodium alginate, hydroxypropyl cellulose, carboxymethyl cellulose, modified cyclodextrin, polyoxypropylene-polyoxyethylene block polymer, and pyrrolidone copolymer.

10. A method for preparing a highly stable, environmentally friendly, fluorine-free foam fire extinguishing agent according to any one of claims 1 to 9, characterized in that, Includes the following steps: S1 Pre-crosslinking Dispersion: Add environmental adaptant and oil-inhibiting crosslinking agent to water according to the formula, stir and disperse, and then let stand for crosslinking to obtain a pre-crosslinking dispersion; S2 gradient compounding: The pre-crosslinked dispersion is heated, and foaming agent system and foam stabilizer are added in sequence according to the formula. The mixture is kept warm and stirred until completely dissolved. A pH adjuster is added to adjust the pH value of the system. After cooling, spreading and reinforcing agent and solvent are added in the formula. After stirring evenly, the mixture is filtered to obtain the fluorine-free foam fire extinguishing agent.

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