A forest flame-retardant suspension, its preparation method and application

Abstract

This invention provides a forest flame-retardant suspension, its preparation method, and its application, comprising the following raw materials by weight percentage: 7-16% flame retardant, 0.7-1.6% char-forming thickener, 1.5-6% film-forming anchoring agent, 0.8-1.4% performance enhancer, 0.1-0.3% chelating dispersant, and the balance being water; wherein the flame retardant is type II ammonium polyphosphate with a degree of polymerization >1000, the char-forming thickener is sodium alginate and xanthan gum, and the film-forming anchoring agent is VAE emulsion. This invention utilizes the hydrophobicity of APPII to solve the problem of easy erosion by dew or rainwater. At the same time, it utilizes the polyphosphoric acid and ammonia produced by the thermal decomposition of APPII. The polyphosphoric acid catalyzes the formation of char from sodium alginate and vegetation cellulose, forming a dense protective layer. This protective layer isolates the transfer of heat and oxygen, cutting off the combustion chain at the source and achieving high flame retardant efficiency. The ammonia can dilute the oxygen concentration in the flame area, playing a gas-phase flame retardant role. The ammonia can also be absorbed or degraded by plants as nitrogen fertilizer, realizing the synergy between forest fire prevention and ecological restoration.

Description

Technical Field

[0001] This invention relates to the field of forest fire prevention materials technology, specifically to a forest fire retardant suspension, its preparation method, and its application. Background Technology

[0002] Forest fires are a major disaster that severely damages the ecological environment and threatens the safety of power transmission lines. Chemical flame retardants are one of the main means of forest fire prevention and control. Currently, most widely used water-based flame retardants are made with low-polymerization degree ammonium polyphosphate (APPI) as the core component. Although they have a certain flame retardant effect, they still have significant defects in practical applications: First, they have poor weather resistance. Due to the extremely high water solubility of APPI, it is easily washed away by dew or rainwater after spraying, which not only leads to the rapid failure of flame retardant performance, but also the loss of phosphorus and nitrogen elements may cause eutrophication of water bodies. Second, they are difficult to process and disperse. Traditional preparation processes often use the method of dissolving the colloid first and then adding the powder. In high-viscosity systems, inorganic powders are difficult to disperse evenly, easily forming "dead lumps" or agglomeration, which can clog the nozzles of precision spraying equipment such as drones. Third, they have poor ecological compatibility. Some synthetic polymer thickeners added to improve the performance of the system are difficult to degrade naturally, and long-term use may cause potential damage to the micro-ecological environment of forest soil. Therefore, developing new high-performance, environmentally friendly flame-retardant systems has become an important research direction in the field of forest fire prevention and control. Summary of the Invention

[0003] The technical problem to be solved by this invention is how to improve the flame retardant properties of flame retardant liquids.

[0004] The present invention solves the above-mentioned technical problems through the following technical means:

[0005] The first aspect of this invention provides a forest flame-retardant suspension, comprising the following raw materials in weight percentages: 7-16% flame retardant, 0.7-1.6% char-forming thickener, 1.5-6% film-forming anchoring agent, 0.8-1.4% performance enhancer, 0.1-0.3% chelating dispersant, and the balance being water; wherein the flame retardant is type II ammonium polyphosphate with a degree of polymerization >1000, the char-forming thickener is sodium alginate and xanthan gum, and the film-forming anchoring agent is VAE emulsion.

[0006] Beneficial effects: This invention utilizes the hydrophobicity of APPII to solve the problem of easy erosion by dew or rainwater. At the same time, it utilizes the polyphosphoric acid and ammonia produced by the thermal decomposition of APPII. The polyphosphoric acid catalyzes the formation of char from sodium alginate and vegetation cellulose, forming a dense protective layer. This protective layer isolates the transfer of heat and oxygen, cutting off the combustion chain at the source and achieving high flame retardant efficiency. The ammonia can dilute the oxygen concentration in the flame area, playing a gas-phase flame retardant role. The ammonia can also be absorbed or degraded by plants as nitrogen fertilizer, realizing the synergy between forest fire prevention and ecological restoration.

[0007] Preferably, the mass ratio of sodium alginate to xanthan gum is 8~12:1~3.

[0008] Preferably, the performance enhancer is hydrophilic nano-silica.

[0009] Preferably, the chelating dispersant is disodium ethylenediaminetetraacetate.

[0010] A second aspect of this invention provides a method for preparing the above-mentioned forest flame-retardant suspension, comprising the following steps: The chelating dispersant is dissolved in water and then flame retardant and performance enhancer are added to obtain a dispersion. A char-forming thickener is added to the dispersion and stirred. Then, a film-forming anchoring agent is added, mixed, allowed to stand to defoam, sieved, and the filtrate is collected to obtain the forest flame retardant suspension.

[0011] Preferably, the flame retardant and performance enhancer are added under high-speed shearing conditions of 1000-1200 rpm, followed by shearing dispersion for 20-30 min.

[0012] Preferably, the sieve mesh size is 200 mesh.

[0013] Beneficial effects: This invention effectively solves the problems of agglomeration and nozzle clogging in high-solids systems by first dispersing flame retardants and performance enhancers at high speed in an aqueous phase, then adding char-forming thickeners to construct a gel network, and finally filtering through a 200-mesh fine filter.

[0014] The third aspect of this invention provides the application of the above-mentioned forest flame retardant suspension or the method for preparing the forest flame retardant suspension in forest fires along power transmission lines.

[0015] Preferably, the forest is a pine forest.

[0016] More preferably, the pine forest is a Masson pine forest.

[0017] Preferably, the forest is a Chinese fir forest.

[0018] Beneficial effects: The forest fire retardant suspension of the present invention can form a dense microcapsule film on the surface of high-oil vegetation such as pine branches or needles, which has excellent resistance to rainwater leaching and flame retardancy, thus realizing the synergy between forest fire prevention and ecological restoration. Attached Figure Description

[0019] Figure 1 These are DTG diagrams of the forest flame-retardant suspensions prepared in Embodiment 2, Comparative Example 1, and Comparative Example 8 of the present invention, used to treat Masson pine branches. Figure 2 These are TG images of pine branches treated with forest flame-retardant suspensions prepared in Embodiment 2, Comparative Example 1, and Comparative Example 8 of the present invention. Figure 3These are TG images of pine needles treated with forest flame-retardant suspensions prepared in Embodiment 2, Comparative Example 1, and Comparative Example 8 of the present invention. Figure 4 This is a DTG diagram of the forest flame retardant suspension prepared in Example 2, Comparative Example 1 and Comparative Example 8 of the present invention for treating Masson pine needles. Figure 5 This is a comparison chart of the cone-shaped calorific mass loss curves of the forest flame-retardant suspensions prepared in Example 2, Comparative Example 1 and Comparative Example 8 of the present invention for treating Masson pine branches. Figure 6 This is a comparison chart of the conical calorific mass loss curves of pine needles treated with forest flame-retardant suspensions prepared in Example 2, Comparative Example 1, and Comparative Example 8 of the present invention. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Unless otherwise specified, all test materials and reagents used in the following examples are commercially available.

[0022] Unless otherwise specified in the embodiments, the techniques or conditions described in the literature in this field or in accordance with the product manual may be followed.

[0023] The flame retardant used in this invention is ammonium polyphosphate with a high degree of polymerization. With a degree of polymerization n>1000, its long-chain structure endows it with excellent thermal stability and extremely low water solubility.

[0024] The key chemical reactions involved in its flame retardant process are as follows:

[0025] When the temperature rises above 275℃, APPII begins to thermally decompose, releasing ammonia and generating polyphosphoric acid. The released ammonia dilutes the oxygen concentration in the flame area, thus playing a role in gas-phase flame retardancy.

[0026]

[0027] polyphosphoric acid generated by decomposition As a strong dehydrating agent, it works with sodium alginate and vegetation cellulose. An esterification reaction occurs, catalytically dehydrating the carbon to form a dense protective layer. This protective layer isolates the transfer of heat and oxygen, thus cutting off the combustion chain at its source.

[0028] The specific steps of the preparation method of the forest flame-retardant suspension in this embodiment of the invention are as follows: S1. First, the highly polymerized ammonium polyphosphate (APPII) and hydrophilic nano-silica are pre-dispersed.

[0029] Place 800-1000g of deionized water in a dispersion vessel, add 2g of disodium ethylenediaminetetraacetate as a dispersing agent, and stir until completely dissolved. Then, turn on a high-speed disperser and set its speed to 1000-1200 rpm. Under high-speed shearing action, first slowly and uniformly add 80-160g of highly polymerized ammonium polyphosphate powder, then add 10-12g of hydrophilic nano-silica in the same manner. Continue shearing and dispersing at this speed for 20-30 minutes to obtain a dispersion. This fully utilizes the extremely low initial viscosity of the system, allowing the hydrophilic nano-silica to fully deagglomerate, achieving a uniform dispersion at the nano- to micron level, laying the foundation for subsequent steps.

[0030] S2. Add xanthan gum and sodium alginate to thicken the dispersion and construct a gel network.

[0031] Adjust the speed of the high-speed disperser to 300-500 rpm to create a gentle but sufficient vortex to maintain uniform mixing. Then, slowly and evenly add 8-12g of pre-mixed sodium alginate and 1-3g of xanthan gum powder to the dispersion. Continue stirring at this speed for 30-40 minutes to ensure that the sodium alginate and xanthan gum are fully wetted, hydrated, and completely dissolved, thus constructing a continuous and stable three-dimensional gel network in situ within the dispersion. This network effectively suspends and fixes the previously dispersed inorganic particles, preventing sedimentation, while also imparting suitable thixotropy and spray viscosity to the system.

[0032] S3. Modify the base liquid by utilizing the film-forming properties of VAE emulsion.

[0033] The stirring speed was further adjusted to 200-300 rpm to reduce shear strength and avoid damaging the formed gel structure. Then, 20-50 g of VAE emulsion was slowly added to the S2 system, and the mixture was continued to mix for 10-20 min under gentle stirring conditions to ensure that the VAE emulsion droplets were evenly dispersed throughout the gel network system, thus ensuring the uniformity of subsequent film formation.

[0034] S4. Refining filtration and finished product collection.

[0035] The modified suspension is allowed to stand to eliminate air bubbles introduced by stirring. It is then pumped into a filtration unit equipped with a 200-mesh (approximately 74 μm) stainless steel filter for further filtration. This step aims to remove trace amounts of large particle agglomerates or incompletely dispersed particles that may have formed during formulation, ensuring the final product's particle size distribution meets the stringent requirements of aerial spraying equipment. The filtrate collected after passing through the filter is the forest fire retardant suspension.

[0036] This invention uses longitudinal comparison of different addition amounts to pinpoint the optimal scope of implementation and cost-effectiveness range of the invention. Furthermore, through horizontal testing of different application objects, it demonstrates the broad applicability of the formulation and its ability to specifically address technical pain points. This logically forms a rigorous chain of evidence, maximizing the support for the scope of protection of the claims and strongly supporting the inventiveness and practicality of the invention.

[0037] Example 1 This embodiment provides a method for preparing a forest flame-retardant suspension, specifically including the following steps: 1000g of deionized water was placed in a dispersion vessel, and 2g of disodium ethylenediaminetetraacetate was added and stirred to dissolve. The high-speed disperser was turned on to 1200rpm, and 80g of highly polymerizable ammonium polyphosphate (APPII) powder and 10g of hydrophilic nano-silica were slowly added. The dispersion was continuously sheared and dispersed for 20min to achieve micron-level agglomeration of inorganic powders to obtain a dispersion. Then the speed was reduced to 300rpm, and 8g of premixed sodium alginate and 1g of xanthan gum powder were slowly sprinkled into the dispersion. The mixture was stirred for 30min to completely dissolve the sodium alginate and xanthan gum and form a gel network. The speed was then further reduced to 200rpm, and 20g of VAE emulsion was slowly added. The mixture was gently mixed for 10min to complete the film-forming modification and obtain a suspension. Finally, the suspension was allowed to stand to defoam, and then pumped into a device equipped with a 200-mesh stainless steel filter for precision filtration. The filtrate was collected to obtain the forest flame retardant suspension.

[0038] Example 2 This embodiment provides a method for preparing a forest flame-retardant suspension, specifically including the following steps: Dissolve 2g of disodium ethylenediaminetetraacetate in 900g of deionized water. Under high-speed shear at 1200rpm, add 120g of APPII and 11g of hydrophilic nano-silica sequentially and disperse for 20min to obtain a dispersion. Then, adjust the speed to 350rpm and evenly sprinkle in a mixture of 10g of sodium alginate and 2g of xanthan gum powder. Stir for 35min until the viscosity of the system increases significantly. Next, reduce the speed to 200rpm, add 35g of VAE emulsion and gently stir for 15min to ensure that the emulsion particles are evenly distributed in the gel network. Finally, allow to stand to defoam and filter through a 200-mesh sieve to collect the filtrate to obtain a forest flame retardant suspension.

[0039] Example 3 This embodiment provides a method for preparing a forest flame-retardant suspension, specifically including the following steps: Dissolve 2g of disodium EDTA in 800g of deionized water, turn on the high-speed shear at 1200rpm, slowly add 160g of APPII and 12g of hydrophilic nano-silica, and disperse for 20min. Then adjust the speed to 400rpm, add 12g of sodium alginate and 3g of xanthan gum, and stir for 40min to construct a high-strength three-dimensional gel network to suspend the high-concentration powder. Next, adjust the speed to 200rpm, add 50g of VAE emulsion and mix for 20min for toughening modification. Finally, after the resulting suspension is allowed to stand to defoam, filter it through a 200-mesh filter to remove impurities, and collect the filtrate to obtain the forest flame retardant suspension.

[0040] Example 4 This embodiment provides a method for preparing a forest flame-retardant suspension, specifically including the following steps: Dissolve 2g of disodium ethylenediaminetetraacetate in 850g of deionized water. Shear and disperse 140g of APPII and 12g of hydrophilic nano-silica at 1200rpm for 20min. Then, adjust the speed to 350rpm, add 10g of sodium alginate and 2.5g of xanthan gum, and stir for 35min to thicken. Next, reduce the speed to 200rpm, add 45g of VAE emulsion, and gently stir for 15min to enhance the binding properties of the system. Finally, allow to stand to defoam and filter through a 200-mesh fine filter. Collect the filtrate to obtain the forest flame retardant suspension.

[0041] Comparative Example 1 This comparative example provides a method for preparing a forest flame retardant suspension. The difference between this comparative example and Example 1 is that high-polymerization degree ammonium polyphosphate is replaced with low-polymerization degree ammonium polyphosphate, while all other aspects are the same as in Example 1.

[0042] Comparative Example 2 This comparative example provides a method for preparing a forest flame retardant suspension. The difference between this comparative example and Example 1 is that sodium alginate is replaced with sodium carboxymethyl cellulose, while all other aspects are the same as in Example 1.

[0043] Comparative Example 3 This comparative example provides a method for preparing a forest flame retardant suspension. The difference between this comparative example and Example 1 is that xanthan gum is replaced with guar gum, while all other aspects are the same as in Example 1.

[0044] Comparative Example 4 This comparative example provides a method for preparing a forest flame retardant suspension. The difference between this comparative example and Example 1 is that the VAE emulsion is replaced with pure acrylic emulsion, while all other aspects are the same as in Example 1.

[0045] Comparative Example 5 This comparative example provides a method for preparing a forest flame retardant suspension. The difference between this comparative example and Example 1 is that the hydrophilic nano-silica is replaced with hydrophilic silica powder, and the average particle size of the hydrophilic silica powder is 1-5 μm. All other aspects are the same as in Example 1.

[0046] Comparative Example 6 This comparative example provides a method for preparing a forest flame retardant suspension. The difference between this comparative example and Example 1 is that the hydrophilic nano-silica is replaced with nano-calcium carbonate, while all other aspects are the same as in Example 1.

[0047] Comparative Example 7 This comparative example provides a method for preparing a forest flame retardant suspension. The difference between this comparative example and Example 1 is that 8g of sodium alginate is replaced with 20g, while all other aspects are the same as in Example 1.

[0048] Comparative Example 8 This comparative example provides a method for preparing a forest flame retardant suspension. The difference between this comparative example and Example 1 is that hydrophilic nano-silica was not added, and deionized water was used to make up the difference. All other aspects are the same as in Example 1.

[0049] Example 1. The forest flame-retardant suspensions prepared in Examples 1-4 and Comparative Examples 1-8 were subjected to performance tests. The specific treatments and groupings are as follows: Blank control group: The needles or branches of Masson pine in an absolute dry state (moisture content <5%) were completely immersed in deionized water for 10 seconds, then removed and air-dried at room temperature for 24 hours before testing. The data obtained were used as a baseline reference.

[0050] The examples and comparative examples are the experimental group: Specific tests are as follows: (1) Thermogravimetric analysis (TA Instruments Q500) was used for testing. Masson pine branches and leaves were pulverized and passed through a 100-mesh sieve. After being thoroughly mixed with the forest fire-retardant suspensions prepared in Examples 1-4 and Comparative Examples 1-8, the mixture was dried at 80℃ for 24 hours to obtain test powder. The powder was then heated from room temperature to 950℃ at a rate of 20K / min under a nitrogen atmosphere. Mass loss data were recorded, and a rate curve was obtained based on the data. The results are as follows: Figure 1-4 As shown.

[0051] (2) Cone Calorimeter Test: The test was conducted according to the international standard ISO 5660-1. The test samples were prepared by thoroughly mixing the pine needle or branch samples with the forest fire-retardant suspensions prepared in Examples 1-4 and Comparative Examples 1-8, and then air-drying them at room temperature for 24 hours. 16g of the test sample (±0.5g) was then laid flat in a standard stainless steel test box measuring 100mm × 100mm. The external heat radiation flux was set to 50kW / m² to simulate the heat radiation environment of a real medium-intensity fire, and the samples were forcibly ignited by an electric spark igniter. Key fire safety parameters such as the ignition time (TTI) and mass loss rate (MLR) were recorded in real time. The results are as follows: Figures 5 to 6 As shown.

[0052] To maintain the clarity of the image, Figures 1 to 4 Only the most representative Example 2 and the typical Comparative Examples 1 and 8 curves are shown. The trends of the remaining unshown examples and comparative examples are basically similar to the curves shown.

[0053] according to Figure 1 It can be seen that the residual char rate of the Masson pine branches in the blank group was extremely low at 800℃. Example 2 had the highest residual char rate, which directly proves that the forest flame retardant suspension prepared in the example formed a stable ceramicized char layer on the wood surface; Comparative Example 1 lost its char due to the use of low-polymerization degree ammonium polyphosphate, and Comparative Example 8 degraded its char shell due to the lack of addition of hydrophilic nano silica. Therefore, the residual char rates of Comparative Example 1 and Comparative Example 8 were significantly lower.

[0054] according to Figure 2 It can be seen that the blank group of Masson pine branches has an extremely high weight loss peak. The maximum weight loss rate peak of Example 2 was significantly reduced to the lowest in the whole group, and the peak position was significantly shifted to the left, indicating that the Masson pine branches were catalyzed to carbonize in advance; the peak attenuation of Comparative Examples 1 and 8 was not as great as that of Example 2.

[0055] according to Figure 3 It can be seen that the needles of the blank group of Masson pine are highly degraded due to their rich oil content. The significant increase in the char residue rate at 800℃ in Example 2 proves that the expanded char layer effectively locks in the boiling oil volatiles; the char residue rates of Comparative Example 1 and Comparative Example 8 are significantly lower because the protective film of low-polymerization degree ammonium polyphosphate is lost, and the char layer of Comparative Example 8 is not stable due to the lack of addition of hydrophilic nano silica.

[0056] according to Figure 4 It can be seen that the blank group of pine needles exhibited a sharp and extremely high weight loss peak. Example 2 significantly flattened this peak, successfully suppressing the instantaneous deflagration of the oil; while the weight loss peak of Comparative Example 8 was still high and sharp, proving that hydrophilic nano-silica plays a core role in constructing the carbon shell.

[0057] according to Figure 5 It can be seen that under strong thermal radiation, the heat release of the pine branches in the blank group increased rapidly. The peak value of the heat release curve of Example 2 dropped to an extremely low level and the shape was broad and gentle; Comparative Examples 1 and 8 both showed obvious secondary heat release peaks caused by char layer cracking in the middle and late stages of combustion.

[0058] according to Figure 6 It can be seen that the needles of the blank group of Masson pine exhibit an extremely narrow and extremely high lethal deflagration peak. Example 2 successfully suppressed this peak, significantly extending the combustion delay and duration; the flame retardant layers of Comparative Examples 1 and 8 failed rapidly under strong radiation, still releasing a large amount of heat, and could not meet the requirements for anti-deflagration.

[0059] 2. The flame retardant suspensions prepared in Examples 1-4 and Comparative Examples 1-8 were subjected to flame retardant performance tests. The test methods and standards are as follows: (1) Limiting Oxygen Index (LOI) Test: The test was conducted in accordance with the national standard GB / T2406.2-2009. A 120mm×10mm×4mm piece of treated, oven-dried pine wood was fixed in the oxygen index measuring instrument, and the minimum oxygen concentration (%) required to maintain stable combustion of the sample was recorded. The results are shown in Table 1.

[0060] (2) Vertical flammability rating (UL-94) test: Evaluation was conducted according to national standard GB / T2408-2021 (V method). A treated, oven-dried pine strip measuring 125mm × 13mm × 4mm was fixed in the vertical flammability apparatus, and a 20mm blue flame was applied to the bottom for 10 seconds. The afterflame times for the first and second tests were recorded. , The flame retardant performance was determined by whether or not molten droplets ignited the absorbent cotton, and the results were shown in Table 1.

[0061] (3) Adsorption dry weight test: The test was conducted in accordance with the national standard XF159-2011. 5g of fresh Masson pine branches and leaves were used as samples. After flame retardant treatment, they were dried to constant weight under standard environmental conditions of (23±2)℃ and relative humidity of 45%~55%. The mass of the samples before and after treatment was weighed, and the adsorption dry weight was calculated according to the standard method. The results are expressed in g / kg. The constant weight determination condition was that the change rate of mass between two weighings 48h apart was not greater than ±0.1%. The results are shown in Table 1.

[0062] Table 1 Performance Test Results

[0063] As shown in Table 1, Examples 1-4 all successfully passed the V-0 rating, achieving self-extinguishing within seconds and without dripping after the fire source was removed. Using low-polymerization-degree APPI (Comparative Example 1) caused APPI to melt and drip upon heating, resulting in a rating of V-2; the absence of nano-silicon or its replacement with large-particle-size powder (Comparative Examples 5, 6, and 8) caused the expanded char layer to brittle and collapse, resulting in a rating of V-1. This demonstrates that the forest fire-retardant suspension of the present invention successfully constructed a high-mechanical-strength, impact-resistant ceramicized char layer.

[0064] Meanwhile, the LOI peak value of Example 2 reached as high as 36.5%, far exceeding the 19.3% of the blank group, achieving a leap from flammable to flame-retardant. The extremely high oxygen demand threshold directly proves that the dense carbon layer catalyzed by the forest flame-retardant suspension prepared in this invention at high temperature has extremely excellent performance in blocking heat and oxygen transfer and isolating volatile combustible gases.

[0065] Example 2 showed an adsorption dry weight of 213.5 g / kg, significantly better than traditional low-viscosity aqueous agents (Comparative Example 1: 77.3 g / kg). High film-forming capacity is a physical prerequisite for flame retardant effect. This data verifies that the gel network constructed by cross-linking VAE emulsion with sodium alginate / xanthan gum can achieve a high liquid retention rate on the wood surface, solving the engineering pain point of easy loss of forestry flame retardants.

[0066] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A forest flame-retardant suspension, characterized in that, The product comprises the following raw materials by weight percentage: 7-16% flame retardant, 0.7-1.6% char-forming thickener, 1.5-6% film-forming anchoring agent, 0.8-1.4% performance enhancer, 0.1-0.3% chelating dispersant, and the balance being water; wherein the flame retardant is type II ammonium polyphosphate with a degree of polymerization >1000, the char-forming thickener is sodium alginate and xanthan gum, and the film-forming anchoring agent is VAE emulsion.

2. The forest flame-retardant suspension according to claim 1, characterized in that, The mass ratio of sodium alginate to xanthan gum is 8~12:1~3.

3. The forest flame-retardant suspension according to claim 1, characterized in that, The performance enhancer is hydrophilic nano-silica.

4. The forest flame-retardant suspension according to claim 1, characterized in that, The chelating dispersant is disodium ethylenediaminetetraacetate.

5. A method for preparing a forest flame-retardant suspension as described in any one of claims 1-4, characterized in that, Includes the following steps: The chelating dispersant is dissolved in water and then flame retardant and performance enhancer are added to obtain a dispersion. A char-forming thickener is added to the dispersion and stirred. Then, a film-forming anchoring agent is added, mixed, allowed to stand to defoam, sieved, and the filtrate is collected to obtain the forest flame retardant suspension.

6. The method for preparing the forest flame-retardant suspension according to claim 5, characterized in that, Flame retardants and performance enhancers are added under high-speed shearing conditions of 1000-1200 rpm, followed by shear dispersion for 20-30 min.

7. The method for preparing the forest flame-retardant suspension according to claim 5, characterized in that, The sieve mesh size is 200 mesh.

8. The application of a forest flame retardant suspension prepared by any one of claims 1-4 or any one of claims 5-7 in forest fires along power transmission lines.

9. The application of the forest flame-retardant suspension according to claim 8 in forest fires along power transmission lines, characterized in that, The forest is a pine forest.

10. The application of the forest flame-retardant suspension according to claim 8 in forest fires along power transmission lines, characterized in that, The forest is a fir forest.

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