A fluorine-free anti-solvent foam fire extinguishing agent based on biological weak cross-linking and its preparation method

Abstract

The present invention discloses a fluorine-free anti-solvent foam fire extinguishing agent based on biological weak cross-linking and a preparation method thereof, and belongs to the technical field of fire extinguishing materials. The raw materials of the fluorine-free anti-solvent foam fire extinguishing agent based on biological weak cross-linking are measured by mass, including: 2-6 parts of bio-based anti-solvent base, 1-5 parts of silica aerogel, 8-15 parts of composite surfactant, 3-6 parts of cross-linking agent, 1-8 parts of cross-linking control auxiliary agent, 3-7 parts of multifunctional auxiliary agent, 5-15 parts of flame retardant, 2-5 parts of preservative and 2000 parts of water. The present invention is suitable for polar liquid fires, and the controllable weak cross-linking of the bio-based anti-solvent base and the cross-linking agent is achieved through balanced regulation, and a fluorine-free anti-solvent foam is obtained by combining aerogel powder and flame retardant components, which can quickly form a polymer gel protective film on the polar liquid, resist the destruction of the foam structure by polar fuel, make the foam have good anti-solubility and stability, and improve the fire extinguishing efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of fire extinguishing materials, and in particular to a fluorine-free and anti-soluble foam fire extinguishing agent based on biological weak cross-linking and a preparation method thereof. Background Art

[0002] Among the disasters faced by human beings, fire is one of the most frequent and harmful sudden disasters. Among them, large liquid fires are difficult to extinguish due to their long burning time, large area, high calorific value, strong thermal radiation and other reasons, which seriously threaten people's lives and property safety. Foam fire extinguishing agent is a foam solution prepared by mixing foam concentrate composed of foaming agent, foam stabilizer, organic solvent and water in a certain proportion. Fire foam is produced by foam generating device, which is mainly used to extinguish such fires caused by liquid fuel. Among them, water-forming foam fire extinguishing agent is recognized as the most effective fire extinguishing technology for extinguishing large liquid fires because it can quickly spread on the surface of liquid to form a layer of water film. However, for fires caused by polar solvents such as alcohols, aldehydes, ketones, esters and organic acids, due to their strong molecular polarity and strong hydrophilicity, they can absorb a large amount of water, causing the foam to break and disappear instantly, and then the water-forming foam fire extinguishing agent loses its effect. Therefore, in order to form a stable covering layer to achieve the fire extinguishing effect, a fire extinguishing agent with solvent resistance, that is, anti-solvent foam fire extinguishing agent, must be used.

[0003] Anti-solvent fire extinguishing agent belongs to gel-type synthetic foam, which has good thixotropic properties, and has the advantages of not being restricted by infusion pipelines, high supply intensity, rapid fire extinguishing, stable storage, and low corrosiveness. The main problem of this type of fire extinguishing agent at present is that its anti-solubility and stability on polar organic substances soluble in water such as alcohols, ethers, and ketones still need to be improved, the adhesion performance is poor, the foam is easy to dehydrate and dissipate, and a large amount of foam liquid needs to be sprayed when extinguishing the fire, and the fire extinguishing efficiency is low. Therefore, in the current research on anti-solubility foam fire extinguishing agents, most scholars add silica aerogel to the original ordinary foam fire extinguishing agent, and increase the viscosity and stability of the foam solution by forming an isolation film on the surface of the polar liquid, thereby improving the anti-solubility of the foam. However, this type of anti-solubility foam fire extinguishing agent still cannot avoid the problem of fluorocarbon surfactants, which causes serious harm to the environment. Therefore, it is urgent to study and improve fluorine-free, highly anti-solubility, and highly stable foam fire extinguishing agents, which are of great practical significance for effectively controlling fires caused by polar solvents and reducing environmental pollution. Summary of the invention

[0004] The purpose of the present invention is to provide a fluorine-free anti-solvent foam fire extinguishing agent based on biological weak cross-linking and a preparation method thereof. The present invention studies the components of the anti-solvent foam from the perspective of environmental protection and high efficiency, and finds that the core components of the anti-solvent foam fire extinguishing agent are film-forming substances and foaming agents with anti-solvent properties. The present invention is suitable for polar liquid fires. The anti-solvent gel foam produced has strong anti-solvent properties and good stability. It can quickly form a polymer gel protective film on the polar liquid to prevent water-soluble fuels from destroying the foam structure, so that the foam has excellent water retention and volume retention rate, and can quickly seal the combustion steam during fire extinguishing, and extinguish the fire efficiently.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] One of the technical solutions of the present invention is to provide a fluorine-free and anti-soluble foam fire extinguishing agent based on weak biological cross-linking, wherein the raw materials, calculated by weight, include:

[0007] 2-6 parts of bio-based anti-solvent base, 1-5 parts of silica aerogel, 8-15 parts of composite surfactant, 3-6 parts of cross-linking agent, 1-8 parts of cross-linking control auxiliary agent, 3-7 parts of multifunctional auxiliary agent, 5-15 parts of flame retardant, 2-5 parts of preservative and 2000 parts of water.

[0008] Preferably, the preparation method of the bio-based anti-solvent base comprises the following steps: crushing locust bean seeds, placing them in water for leaching, filtering, adding ethanol to the filtrate, and drying to obtain a crude extract 1; then adding ethanol to the crude extract 1 for alcohol precipitation, centrifuging, and the obtained supernatant is the crude extract 2;

[0009] The crude extract 2 is dissolved in an enzymatic hydrolysis buffer, an enzyme is added for enzymatic hydrolysis, and then the enzyme is inactivated to remove substances with a molecular weight <900D, and then separated by ultrafiltration tubes of 10KD and 300KD in sequence to obtain the bio-based anti-solvent base agent.

[0010] In the present invention, the substances with molecular weight <900D mainly refer to insoluble enzymatic residues, as well as proteins and amino groups in the bio-based anti-solvent base.

[0011] More preferably, the extraction time in water is 24 hours; the drying temperature is 80-100°C and the time is 30-50 minutes; the volume ratio of the crude extract to ethanol is 1:4, the alcohol precipitation temperature is 5°C and the time is 12 hours; the centrifugation is performed at a speed of 10,000 r / min for 15 minutes.

[0012] More preferably, the mass ratio of the crude extract 2 to the enzymatic hydrolysis buffer is 1:9; the amount of the enzyme added is 2-5wt% of the mass of the enzymatic hydrolysis buffer; the temperature of the enzymatic hydrolysis is 30-45°C, and the time is 12-24h; the enzymatic hydrolysis buffer is a boric acid-borax buffer with a pH of 7.4 and a concentration of 0.01M; and the enzyme includes one or more of amylase, glucanase, chitinase, cellulase and pectinase.

[0013] After the pretreatment method defined in the present invention, polysaccharide impurities such as glucan, chitin, cellulose, pectin, etc. mixed in locust bean seeds can be enzymatically removed, and other proteins can be removed, only the target substance is retained, and the purity of the bio-based anti-solvent base agent is ensured.

[0014] Bio-based anti-solvent base agents are non-toxic, harmless, easily degradable and environmentally friendly. In addition, each monosaccharide residue in the macromolecular chain of the bio-based anti-solvent base agent has two cis-hydroxyl groups, which can undergo cross-linking reactions with tetrahydroxyl groups and borate ions. When the gel solution is alkaline and there are enough dissociated borate ions, gelation occurs, which can form a protective film between the polar fuel and the foam, thereby improving the foam's ability to resist erosion by polar fuels.

[0015] Preferably, the composite surfactant comprises a hydrocarbon surfactant and an organosilicon surfactant; the mass ratio of the hydrocarbon surfactant to the organosilicon surfactant is 1-2:1; the hydrocarbon surfactant comprises one or more of sodium dodecyl sulfate (SDS), dodecyl betaine (BS-12) and alkyl polyglycoside (APG); the organosilicon surfactant is 8000, 8022, One or more of 8002, Dow Corning-0193 silicone surfactant and ionic 6950 silicone surfactant.

[0016] In the present invention, the surfactant is obtained by compounding a hydrocarbon surfactant and an organosilicon surfactant, which reduces the surface tension of the aqueous solution to the greatest extent without containing a fluorocarbon surfactant, and maintains good spreading performance, and produces excellent synergistic effects with anti-solvent film-forming substances (silicon dioxide aerogel and bio-based anti-solvent base).

[0017] Preferably, the cross-linking agent includes borax (sodium tetraborate) or boric acid; the cross-linking control auxiliary agent is calcium carbonate; the multifunctional auxiliary agent is sodium bicarbonate; the flame retardant includes diammonium hydrogen phosphate and / or ammonium polyphosphate; the preservative includes one or more of quaternary ammonium salt preservatives, parabens, gallic acid esters and propylparaben.

[0018] The multifunctional auxiliary agent (sodium bicarbonate) added in the present invention is easily decomposed into CO2 under heating conditions to expand the volume of the foam gel, thereby enhancing the covering performance of the material and improving the fire prevention and extinguishing ability.

[0019] In the solution system of the present invention, borate is hydrolyzed to produce borate and hydrogen ions, and then the borate ions react with the cis-dihydroxyl groups on the side chains of the bio-based anti-solvent base, and the boron atom shares an electron pair with the oxygen atom in the hydroxyl group to generate a coordination bond, which then cross-links to form a gel network. The cations in the cross-linking control agent released by the hydrogen ions, in turn, promote the hydrolysis of the borate. The cross-linking control agent controls the degree of hydrolysis, and then controls the degree of cross-linking and viscosity of the system.

[0020] Silica aerogel can be dispersed into the liquid film of the foam during the foaming process. In this case, the aerogel forms a single protective layer inside the foam. Unlike surfactants, aerogel forms a rigid film that can significantly improve the burning resistance of the foam.

[0021] The second technical solution of the present invention is to provide a method for preparing the above-mentioned fluorine-free and anti-solvent foam fire extinguishing agent based on weak biological cross-linking, comprising the following steps:

[0022] Dissolving the bio-based anti-solvent base in part of the water, then adding the flame retardant and the multifunctional additive to adjust the pH value to 8-9, swelling, and forming component A; mixing the remaining water with the composite surfactant, silica aerogel, crosslinking agent, crosslinking control agent and preservative to form component B;

[0023] Component A and component B are mixed and reacted to obtain the fluorine-free and anti-solvent foam fire extinguishing agent based on biological weak cross-linking.

[0024] In the process of preparing the fluorine-free anti-solvent foam fire extinguishing agent of the present invention, the raw material system is divided into component A and component B, mainly to prevent the effective components in A and B from reacting prematurely, which is not conducive to the generation of the required substances. Therefore, the raw materials are prepared in a dispersed manner and mixed after all the substances are dissolved.

[0025] Preferably, the reaction temperature is 50-60°C and the reaction time is 10-30 min.

[0026] The third technical solution of the present invention is to provide an application of the above-mentioned fluorine-free and anti-solvent foam fire extinguishing agent based on biological weak cross-linking in the field of polar liquid fire extinguishing agents.

[0027] The beneficial technical effects of the present invention are as follows:

[0028] The present invention designs a fluorine-free foam fire extinguishing agent based on biological weak cross-linking, using hydrocarbon surfactants and silicone surfactants as composite foaming agents, and forming a cross-linking network in the foam liquid film through controllable weak cross-linking between the bio-based anti-solvent base and the cross-linking agent, so as to resist the destruction of the foam structure by polar fuels, and make the foam have good anti-solubility and stability.

[0029] The silica aerogel used in the present invention can be dispersed on the liquid film of the foam during the foaming process. The silica aerogel forms a single protective layer inside the foam. Unlike surfactants, the aerogel forms a rigid film, which can significantly improve the burning resistance of the foam.

[0030] The fluorine-free anti-solvent foam fire extinguishing agent prepared by the present invention uses a bio-based anti-solvent base agent as the core for anti-solvent treatment, does not contain fluorocarbon surfactants, and the reagents used are clean and environmentally friendly, do not pollute the environment, have low operating costs, are easy to prepare, and are convenient for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 The following are SEM images of the products of Example 1 and Example 2. (a) is Example 1, and (b) is Example 2.

[0033] Figure 2 This is a physical picture of the product of Example 2.

[0034] Figure 3 This is the infrared spectrum of the product of Example 3.

[0035] Figure 4 This is a graph showing the change in foaming volume of the product of Example 2 as a function of the concentration of the bio-based anti-solvent base.

[0036] Figure 5 This is a graph showing the change in foam half-life of the product of Example 2 as a function of the concentration of the bio-based anti-solvent base. DETAILED DESCRIPTION

[0037] Now, various exemplary embodiments of the present invention are described in detail, and this detailed description should not be considered as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, characteristics and embodiments of the present invention. It should be understood that the terms described in the present invention are only for describing specific embodiments and are not used to limit the present invention.

[0038] In addition, for the numerical range in the present invention, it is understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0039] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the invention pertains. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention.

[0040] The words “include,” “including,” “have,” “contain,” etc. used in the present invention are open-ended terms, meaning including but not limited to.

[0041] The term "overnight" as used herein refers to 12 hours unless otherwise specified.

[0042] The "room temperature" described in the present invention is 20-30°C unless otherwise specified.

[0043] All raw materials used in the following examples and comparative examples of the present invention are commercially available products.

[0044] Example 1

[0045] The fluorine-free anti-solvent foam fire extinguishing agent is composed of the following raw materials in parts by mass:

[0046] 2 parts of bio-based anti-solvent base, 1 part of silica aerogel, composite surfactant (sodium dodecylbenzene sulfonate and 8000), 8 parts of calcium carbonate (BPA), 3 parts of borax (BPA), 1 part of calcium carbonate (Calcium carbonate), 3 parts of sodium bicarbonate (Sodium bicarbonate), 5 parts of flame retardant (diammonium hydrogen phosphate), 2 parts of preservative (Gallic acid ester) and 2000 parts of deionized water.

[0047] Preparation of bio-based anti-solvent base:

[0048] 4 g of locust bean seeds were crushed to a particle size of 3 mm, placed in 500 mL of deionized water for 24 h, filtered, 1500 mL of ethanol was added to the filtrate, and then dried at 85°C for 50 min, ground and passed through a 25-mesh sieve to obtain a crude extract 1, 4 times the volume of ethanol as that of the crude extract 1 was added, and the mixture was precipitated overnight in a refrigerator at 5°C, centrifuged at 10000 r / min for 15 min, and the obtained supernatant was washed three times with ethanol by centrifugation to obtain a crude extract 2;

[0049] The crude extract 2 was dissolved in a boric acid-borax buffer solution with a pH of 7.4 and a concentration of 0.01M (the mass ratio of the crude extract 2 to the enzymatic hydrolysis buffer was 1:9), and an amylase equivalent to 3wt% of the solution system was added, and enzymatic hydrolysis was carried out at 37°C overnight; using the sevage method, 100mL of n-butanol and 500mL of chloroform solution were added to the solution, shaken, and centrifuged at 5000rpm for 20min to remove the enzyme in the enzymatic hydrolysis product, and small molecules with a molecular weight of <900D were removed by dialysis, and then separated using 10KD and 300KD ultrafiltration tubes in turn to further eliminate residual small proteins and obtain a bio-based anti-solvent base agent.

[0050] Preparation of fluorine-free anti-solvent foam fire extinguishing agent:

[0051] The bio-based anti-solvent base is diluted in 1000 parts of deionized water at room temperature, and the dissolution process is continuously stirred at a speed of 600 r / min; after the bio-based anti-solvent base is completely dissolved, a flame retardant and a multifunctional additive are added to the solution to adjust the pH value to 8 to form component A.

[0052] Take the composite surfactant and dissolve it in 1000 parts of deionized water at room temperature; after the surfactant is completely dissolved, use a stirrer to continuously stir at a speed of 600r / min, add silica aerogel during the stirring process, and after 20 minutes, take the cross-linking agent, cross-linking control auxiliary agent and preservative and add them to the solution until the solution becomes clear and transparent after complete dissolution, thereby forming component B.

[0053] Add A to B and mix thoroughly. Adjust the stirring speed of the stirrer to 1200r / min. Stir at 50°C for 20min, then stop and remove the precipitate. The resulting suspension is the fluorine-free, anti-solvent foam fire extinguishing agent.

[0054] Example 2

[0055] The fluorine-free anti-solvent foam fire extinguishing agent is composed of the following raw materials in parts by mass:

[0056] 4 parts of bio-based anti-solvent base, 3 parts of silica aerogel, composite surfactant (sodium dodecyl sulfate, alkyl glycoside, 8022) 12 parts, cross-linking agent (boric acid) 6 parts, cross-linking control auxiliary agent (calcium carbonate) 3 parts, multifunctional auxiliary agent (sodium bicarbonate) 5 parts, flame retardant (ammonium polyphosphate) 10 parts, preservative (paraben) 4 parts and deionized water 2000 parts.

[0057] Preparation of bio-based anti-solvent base:

[0058] 4 g of locust bean seeds were crushed to a particle size of 3 mm, placed in 500 mL of deionized water for 24 h, filtered, 1500 mL of ethanol was added to the filtrate, and then dried at 85°C for 50 min, ground and passed through a 25-mesh sieve to obtain a crude extract 1, 4 times the volume of ethanol as that of the crude extract 1 was added, and the mixture was precipitated overnight in a refrigerator at 5°C, centrifuged at 10000 r / min for 15 min, and the obtained supernatant was washed three times with ethanol by centrifugation to obtain a crude extract 2;

[0059] The crude extract 2 was dissolved in a boric acid-borax buffer solution with a pH of 7.4 and a concentration of 0.01M (the mass ratio of the crude extract 2 to the enzymatic hydrolysis buffer was 1:9), and a glucose enzyme equivalent to 3wt% of the solution system was added, and enzymatic hydrolysis was carried out at 37°C overnight; using the sevage method, 100mL of n-butanol and 500mL of chloroform solution were added to the solution, and the solution was shaken and centrifuged at 5000rpm for 20min to remove the enzyme in the enzymatic hydrolysis product, and small molecules with a molecular weight of <900D were removed by dialysis, and then separated using 10KD and 300KD ultrafiltration tubes in turn to further eliminate residual small proteins and obtain a bio-based anti-solvent base agent.

[0060] Preparation of fluorine-free anti-solvent foam fire extinguishing agent:

[0061] The bio-based anti-solvent base is diluted in 1000 parts of deionized water at room temperature, and the dissolution process is continuously stirred at a speed of 600 r / min; after the bio-based anti-solvent base is completely dissolved, a flame retardant and a multifunctional additive are added to the solution to adjust the pH value to 8 to form component A.

[0062] Take the composite surfactant and dissolve it in 1000 parts of deionized water at room temperature; after the surfactant is completely dissolved, use a stirrer to continuously stir at a speed of 600r / min, add silica aerogel during the stirring process, and after 20 minutes, take the cross-linking agent, cross-linking control auxiliary agent and preservative and add them to the solution until the solution becomes clear and transparent after complete dissolution, thereby forming component B.

[0063] Add A to B and mix thoroughly. Adjust the stirring speed of the stirrer to 1200r / min. Stir at 55°C for 20min, then stop and remove the precipitate. The resulting suspension is the fluorine-free, anti-solvent foam fire extinguishing agent.

[0064] Figure 1 The SEM images of the products of Example 1 and Example 2 are shown in Figure 1. (a) is Example 1, and (b) is Example 2. Figure 1 It can be seen that the inner wall structure of the product of the present invention is very dense, which can improve the water retention of the gel.

[0065] Figure 2 This is a physical picture of the product of Example 2.

[0066] Example 3

[0067] The fluorine-free anti-solvent foam fire extinguishing agent is composed of the following raw materials in parts by mass:

[0068] 6 parts of bio-based anti-solvent base agent, 5 parts of silica aerogel, 15 parts of composite surfactant (dodecyl betaine, alkyl glycoside, 6950 silicone surfactant in a mass ratio of 1:1:1), 6 parts of cross-linking agent (borax), 8 parts of cross-linking control aid (calcium carbonate), 7 parts of multifunctional aid (sodium bicarbonate), 15 parts of flame retardant (ammonium dihydrogen phosphate, ammonium polyphosphate in a mass ratio of 2:1), 4 parts of preservative (propyl paraben) and 2000 parts of deionized water.

[0069] Preparation of bio-based anti-solvent base:

[0070] 4 g of locust bean seeds were crushed to a particle size of 3 mm, placed in 500 mL of deionized water for 24 h, filtered, 1500 mL of ethanol was added to the filtrate, and then dried at 85°C for 50 min, ground and passed through a 25-mesh sieve to obtain a crude extract 1, 4 times the volume of ethanol as that of the crude extract 1 was added, and the mixture was precipitated overnight in a refrigerator at 5°C, centrifuged at 10000 r / min for 15 min, and the obtained supernatant was washed three times with ethanol by centrifugation to obtain a crude extract 2;

[0071] The crude extract 2 was dissolved in a boric acid-borax buffer solution with a pH of 7.4 and a concentration of 0.01 M (the mass ratio of the crude extract 2 to the enzymatic hydrolysis buffer was 1:9), and cellulase equivalent to 3 wt% of the solution system was added, and enzymatic hydrolysis was carried out at 37°C overnight; using the sevage method, 100 mL of n-butanol and 500 mL of chloroform solution were added to the solution, shaken, and centrifuged at 5000 rpm for 20 min to remove the enzyme in the enzymatic hydrolysis product, and small molecules with a molecular weight of <900D were removed by dialysis, and then separated using 10KD and 300KD ultrafiltration tubes in turn to further eliminate residual small proteins to obtain a bio-based anti-solvent base agent.

[0072] Preparation of fluorine-free anti-solvent foam fire extinguishing agent:

[0073] The bio-based anti-solvent base is diluted in 1000 parts of deionized water at room temperature, and the dissolution process is continuously stirred at a speed of 600 r / min; after the bio-based anti-solvent base is completely dissolved, a flame retardant and a multifunctional additive are added to the solution to adjust the pH value to 8 to form component A.

[0074] Take the composite surfactant and dissolve it in 1000 parts of deionized water at room temperature; after the surfactant is completely dissolved, use a stirrer to continuously stir at a speed of 600r / min, add silica aerogel during the stirring process, and after 20 minutes, take the cross-linking agent, cross-linking control auxiliary agent and preservative and add them to the solution until the solution becomes clear and transparent after complete dissolution, thereby forming component B.

[0075] Add A to B and mix thoroughly. Adjust the stirring rate of the stirrer to 1200r / min. Stir at 60°C for 20min, then stop and remove the precipitate. The resulting suspension is the fluorine-free, anti-solvent foam fire extinguishing agent.

[0076] Figure 3 This is the infrared spectrum of the product of Example 3.

[0077] Comparative Example 1 (common fluorine-free foam fire extinguishing agent in the art)

[0078] Preparation of fluorine-free anti-solvent foam fire extinguishing agent:

[0079] Take 12g of composite surfactant (sodium dodecyl sulfate, alkyl glucoside, 8002) was dissolved in 1000 mL of deionized water at room temperature; after the surfactant was completely dissolved, the stirrer was continuously stirred at a speed of 600 r / min, 0.5 g of sodium carboxymethyl cellulose was added during the stirring process, and 8 g of ammonium polyphosphate, 5 g of paraben, 4 g of ethylene glycol and 4 g of urea were added to the solution after 20 min, and the stirring was stopped until the solution was completely dissolved to obtain a fluorine-free anti-solvent foam fire extinguishing agent.

[0080] Comparative Example 2 (Existing foam fire extinguishing agent with compound surfactant)

[0081] Preparation of fluorine-free anti-solvent foam fire extinguishing agent:

[0082] Start the mixer at a speed of 300 r / min, add 15g propylene glycol, 15g ethylene glycol, 22g isopropanol and 1000mL water into the container, and stir at room temperature for 10min; add 2g xanthan gum and 5g urea, stop stirring after all are dissolved, swell for 1h, continue stirring, add 3.5g sodium dodecyl sulfate, 2g dodecyl betaine, 10g sodium lauryl amphoteric acetate, 3g modified silicone surfactant, 15g alkyl polyglycoside, stir at a speed of 1200 r / min for 30min, then stop to obtain a fluorine-free anti-solvent foam fire extinguishing agent.

[0083] Comparative Example 3

[0084] The only difference from Example 2 is that the preparation method of the bio-based anti-solvent base is modified to only enzymatically hydrolyze the crude extract 2 without dialysis and ultrafiltration tube separation.

[0085] Comparative Example 4

[0086] The only difference from Example 2 is that the silica aerogel is replaced by an equal mass of a bio-based antisolvent agent.

[0087] Effect verification

[0088] 1. The fire extinguishing agents in Examples 1-3 and Comparative Examples 1-4 were subjected to fire extinguishing and anti-burning experiments, using a square steel oil pan with a size of 35*35*5 cm, an anti-burning tank with a diameter of 6 cm and a height of 5 cm; the fuel used was anhydrous ethanol.

[0089] The specific fire extinguishing steps are as follows:

[0090] (1) Pour 500 mL of anhydrous ethanol into the oil pan and ignite it;

[0091] (2) After 60 seconds of pre-combustion, extinguish the fire in the same way;

[0092] (3) Record the moment when the flame is completely extinguished, which is the fire extinguishing time;

[0093] (4) Continue to apply foam after the flame is extinguished, and stop applying foam when the total foam supply time reaches 3 minutes;

[0094] (5) Place an oil tank containing 100 mL of anhydrous ethanol in the center of the oil pan, with the upper edge of the anti-burn tank and the upper edge of the foam layer at the same level;

[0095] (6) Ignite the oil tank and record the time when flames appear on 100% of the oil pan area. This is the anti-burning time of the bubble.

[0096] The results are shown in Table 1.

[0097] Table 1

[0098] Fire extinguishing time / s Burning time / min Example 1 75 10 Example 2 56 15 Example 3 67 13 Comparative Example 1 126 8 Comparative Example 2 105 7 Comparative Example 3 81 11 Comparative Example 4 109 6

[0099] 2. Foam anti-solubility and stability test

[0100] The anti-solubility test was conducted on Examples 1-3 and Comparative Examples 1-4. The same mass of experimental foam was slowly injected onto the surface of the ethanol solution through a foam generator and a foam injector to make the foam evenly distributed. The foam volume, lifespan, and gel film formation of the test liquid on the ethanol liquid surface were observed and recorded. The results are shown in Table 2.

[0101] Table 2

[0102] Initial foam volume / mL Foam volume after 5 minutes / mL Whether a gel film is formed Example 1 377 343 yes Example 2 405 370 yes Example 3 326 168 yes Comparative Example 1 188 73 yes Comparative Example 2 351 142 no Comparative Example 3 270 65 yes Comparative Example 4 175 32 no

[0103] The experiment found that compared with Comparative Examples 1-4, the initial foam volume of Examples 1-3 tended to be stable, among which Example 1-2 remained basically unchanged, the foam broke more slowly on the ethanol solution, and the volume reduction rate was significantly slower than that of Comparative Example 1. Examples 1-3 had good film-forming effects, among which Example 1 had the best effect, and could form a continuous and stable gel film on the surface of the ethanol solution, while the gel film of Comparative Example 1 was unstable, and the anti-solubility of the foam liquid was poor, and Comparative Examples 2 and Comparative Examples 4 failed to form a gel film.

[0104] 3. Foaming volume and foam half-life test

[0105] The foaming volume and foam half-life test were performed by changing the mass fraction of the bio-based anti-solvent base added in Example 2 (the data when the mass fraction was 1, 2, 3, 4, 5, 6, 7, and 8 were tested respectively); the specific test method was: 100 mL of the foam liquid to be tested was stirred at a speed of 1200 r / min for 3 minutes for foaming, and the foam volume and the time required for 50 mL of liquid to precipitate were recorded. The results are shown in Figure 4-5 shown.

[0106] Figure 4 This is a graph showing the change in foaming volume of the product of Example 2 as a function of the concentration of the bio-based anti-solvent base.

[0107] Figure 5 This is a graph showing the change in foam half-life of the product of Example 2 as a function of the concentration of the bio-based anti-solvent base.

[0108] pass Figure 4-5 It can be clearly seen that as the content of the bio-based anti-solvent base increases, the volume of the foam gradually decreases. At the same time, the stability of the foam is significantly improved, and the half-life increases with each increase in the anti-solvent base. This phenomenon occurs because the viscosity of the system gradually increases with the increase in the concentration of the anti-solvent base. The increase in solution viscosity causes the liquid film that forms the foam to become thicker and more elastic, which can effectively resist the precipitation of the foam. Figure 5 The trend of is similar to the viscosity change, providing good validation for this observation.

[0109] The increase in viscosity promotes the growth of half-life, but also leads to the weakening of foaming performance. In fact, the greater the viscosity, the more difficult it becomes to form foam. Therefore, although the stability of the foam is improved, the foaming performance is reduced. In general, according to practical needs, we hope that the foaming volume of gel foam is as large as possible. However, when determining the amount of bio-based anti-solvent base added in the system, it is necessary to strike a balance between stability and foaming performance. Therefore, the inventors based on Figure 4-5 Considering the technical effect, the amount of bio-based anti-solvent base is preferably 2-6 parts, which ensures stability while maintaining higher foaming properties.

[0110] The embodiments described above are only descriptions of the preferred embodiments of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A fluorine-free, anti-solvent foam fire extinguishing agent based on weak biological cross-linking, characterized in that: Raw materials, calculated by mass, include: 2-6 parts of bio-based anti-solvent base, 1-5 parts of silica aerogel, 8-15 parts of composite surfactant, 3-6 parts of cross-linking agent, 1-8 parts of cross-linking control auxiliary agent, 3-7 parts of multifunctional auxiliary agent, 5-15 parts of flame retardant, 2-5 parts of preservative and 2000 parts of water; The preparation method of the bio-based anti-solvent base comprises the following steps: crushing locust bean seeds, placing them in water for leaching, filtering, adding ethanol to the filtrate, and drying to obtain a crude extract 1; then adding ethanol to the crude extract 1 for alcohol precipitation, centrifuging, and obtaining a supernatant as the crude extract 2; The crude extract 2 is dissolved in an enzymatic hydrolysis buffer, an enzyme is added for enzymatic hydrolysis, and then the enzyme is inactivated to remove substances with a molecular weight <900D, and then separated by ultrafiltration tubes of 10KD and 300KD in sequence to obtain the bio-based anti-solvent base agent; The composite surfactant comprises a hydrocarbon surfactant and an organosilicon surfactant; the mass ratio of the hydrocarbon surfactant to the organosilicon surfactant is 1-2:1; the hydrocarbon surfactant comprises one or more of sodium lauryl sulfate, lauryl betaine and alkyl glycoside; the organosilicon surfactant is One or more of Dow Corning-0193 silicone surfactant and ionic 6950 silicone surfactant; The cross-linking agent includes borax or boric acid; the cross-linking control auxiliary agent is calcium carbonate; the multifunctional auxiliary agent is sodium bicarbonate; the flame retardant includes diammonium hydrogen phosphate and / or ammonium polyphosphate; the preservative includes one or more of quaternary ammonium salt preservatives, parabens, gallic acid esters and propyl paraben; The mass ratio of the crude extract 2 to the enzymatic hydrolysis buffer is 1:9; the amount of the enzyme added is 2-5wt% of the mass of the enzymatic hydrolysis buffer; the temperature of the enzymatic hydrolysis is 30-45°C, and the time is 12-24h; the enzymatic hydrolysis buffer is a boric acid-borax buffer with a pH of 7.4 and a concentration of 0.01M; the enzyme includes one or more of amylase, glucanase, chitinase, cellulase and pectinase.

2. The fluorine-free, solvent-resistant foam fire extinguishing agent according to claim 1, characterized in that: The extraction time in water is 24 hours; the drying temperature is 80-100°C and the time is 30-50 minutes; the volume ratio of the crude extract to ethanol is 1:4, the temperature of the alcohol precipitation is 5°C and the time is 12 hours; the centrifugation is performed at a speed of 10,000 r / min for 15 minutes.

3. A method for preparing the fluorine-free and anti-solvent foam fire extinguishing agent based on biological weak cross-linking according to claim 1 or 2, characterized in that: The following steps are involved: Dissolving the bio-based anti-solvent base in part of the water, then adding the flame retardant and the multifunctional additive to adjust the pH value to 8-9 to form component A; mixing the remaining water with the composite surfactant, silica aerogel, crosslinking agent, crosslinking control agent and preservative to form component B; Component A and component B are mixed and reacted to obtain the fluorine-free and anti-solvent foam fire extinguishing agent based on biological weak cross-linking.

4. The preparation method according to claim 3, characterized in that: The reaction temperature is 50-60°C and the reaction time is 10-30 minutes.

5. Use of the biological weakly cross-linked fluorine-free and anti-solvent foam fire extinguishing agent according to claim 1 or 2 in the field of polar liquid fire extinguishing agents.

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