Fire extinguishing foam composition

Abstract

A fire extinguishing foam concentrate that is free or substantially free of fluorine-containing surfactants is disclosed. A fire extinguishing foam concentrate includes water and from 25% to 38% by weight of a surfactant blend including at least one selected cationic quaternary ammonium compound, at least one selected alkyl amine oxide nonionic surfactant, and at least one selected alkyl sulfate anionic surfactant. Each selected surfactant has an average alkyl or alkylene carbon chain length of from 8 to 10 carbon atoms. The fire extinguishing foam concentrate may be combined with other fire extinguishing foam components to form a fire extinguishing foam composition. Also disclosed is a fire extinguishing method comprising inflating a fire extinguishing foam composition comprising a surfactant blend to form a fire extinguishing foam that is applied to a surface of a fire or a volatile flammable liquid.

Description

TECHNICAL FIELD

[0001] The present technology relates to surfactant blends for fire-fighting foam concentrates and compositions, and in particular to surfactant blends that are free or substantially free of fluorocarbons. BACKGROUND

[0002] Class B fires are fires involving flammable liquids, such as gasoline, kerosene, and other fuels and hydrocarbons. Water-based, film-forming foams for Class B fire-fighting applications must be able to extinguish fires, form a strong foam in the presence of hydrocarbons, and be a barrier to hydrocarbon vapors. Traditional AFFFs for Class B fires typically include a proprietary mixture of fluorinated surfactants and other materials and rely on the unique properties of the fluorosurfactants to create a foam that can spread to the surface of the hydrocarbon liquid and seal in any flammable volatile components, thereby extinguishing the fire and preventing the hot hydrocarbon liquid from reigniting. However, fluorosurfactants have come under scrutiny as more and more evidence has shown that they bioaccumulate and can be carcinogenic. As a result, there is an increasing push in the market to eliminate or substantially reduce the use of fluorosurfactants in fire-fighting foams. One difficulty is that many non-fluorinated surfactants do not have comparable performance to fluorosurfactants, resulting in AFFFs with poor fire-fighting performance. There is an ongoing need for non-fluorinated surfactants that are safer from a health and environmental perspective, but that can meet the demanding requirements of AFFFs for Class B fire-fighting applications.

[0003] Applicants have determined that surfactant blends comprising specific cationic, anionic, and nonionic surfactants having specific carbon chain lengths can provide fire-fighting foam concentrates and compositions with properties suitable for Class B fire-fighting applications, while also advancing the United Nations Sustainable Development Goals (“SDGs”). The surfactants can be derived from renewable fatty acid feedstocks and can be effective replacements for fluorosurfactants that have negative impacts on health and the environment. These benefits advance SDG #3 (Good Health and Well-Being) and SDG #12 (Responsible Consumption and Production). SUMMARY

[0004] The present technology generally relates to aqueous fire-fighting foam concentrates comprising a surfactant blend comprising at least one quaternary ammonium cationic surfactant having one or two carbon chains with an average carbon chain length of 8 to 10 carbon atoms, at least one amine oxide nonionic surfactant having a carbon chain with an average carbon chain length of 8 to 10 carbon atoms, and at least one alkyl sulfate anionic surfactant having an average carbon chain length of 8 to 10 carbon atoms. Surprisingly, it has been found that the combination of cationic, nonionic, and anionic surfactants having specific carbon chain lengths provides a synergistic surfactant blend with properties suitable for AFFF Class B fire-fighting foam applications.

[0005] One aspect of the present technology is an aqueous fire-fighting foam concentrate comprising a surfactant blend in an amount of about 25 wt% to about 38 wt% of the concentrate, the surfactant blend comprising (i) a cationic surfactant having the general formula:

[0006]

[0007] wherein R1is a linear or branched, saturated or unsaturated alkyl or olefin chain having an average chain length of 8 to 10 carbon atoms; R2is H or a linear or branched, saturated or unsaturated alkyl or olefin chain having 1 to 10 carbon atoms; R3is H, methyl or ethyl; R4is H, methyl or ethyl; and X"is a monovalent anion, preferably a halide; (ii) an alkyl amine oxide non-ionic surfactant having an alkyl moiety with an average carbon chain length of 8 to 10 carbon atoms; and (iii) an anionic surfactant having the general formula:

[0008] R'-X2 - Y +

[0009] wherein R' is a linear or branched, saturated or unsaturated alkyl or olefin chain having an average chain length of 8 to 10 carbon atoms, X2 - is a sulfate radical, and Y + is a cationic counterion, preferably selected from sodium, potassium and ammonium; wherein the cationic surfactant, the non-ionic surfactant and the anionic surfactant are present in the surfactant blend in a molar ratio of about 0.25-1.0 : 0.25-1.0 : 0.25-1.0; and water to a total of 100 wt% of the concentrate.

[0010] Another aspect of the present technology is a fire-fighting foam composition comprising (a) about 0.5% to about 12% by weight of the composition of a surfactant blend, the surfactant blend comprising (i) a cationic surfactant having the general formula:

[0011]

[0012] wherein R1is a linear or branched, saturated or unsaturated alkyl or olefin chain having an average chain length of 8 to 10 carbon atoms; R2is H or a linear or branched, saturated or unsaturated alkyl or olefin chain having 1 to 10 carbon atoms; R3is H, methyl or ethyl; R4is H, methyl or ethyl; and X"is a monovalent anion counterion, preferably a halide, most preferably Cl - or Br - ; (ii) an alkyl amine oxide non-ionic surfactant having an alkyl moiety with an average carbon chain length of 8 to 10 carbon atoms; and (iii) an anionic surfactant having the general formula:

[0013] R'-X2 - Y +

[0014] Where R' is a straight or branched, saturated or unsaturated alkyl or olefin chain with an average chain length of 8 to 10 carbon atoms, X2 - It is a sulfate group, and Y + The surfactant is a cationic balanced ion, preferably selected from sodium, potassium, ammonium and substituted ammonium; wherein the cationic surfactant, the nonionic surfactant and the anionic surfactant are present in the surfactant blend in a molar ratio of about 0.25-1.0:0.25-1.0:0.25-1.0; (b) at least one additive selected from thickeners, foam stabilizers and polymers; and (c) water to a total of 100% by weight of the composition.

[0015] Another aspect of the present invention is a method for extinguishing a fire, comprising (a) inflating a fire extinguishing foam composition to form inflated fire extinguishing foam; and (b) applying the inflated fire extinguishing foam to a fire, wherein the fire extinguishing foam composition comprises water and a surfactant blend of about 0.5% to about 12% by weight of the composition, the surfactant blend comprising (i) a cationic surfactant having the following general formula:

[0016]

[0017] Wherein R1 is a straight-chain or branched, saturated or unsaturated alkyl or olefin chain with an average chain length of 8 to 10 carbon atoms; R2 is H or a straight-chain or branched, saturated or unsaturated alkyl or olefin chain having 1 to 10 carbon atoms; R3 is H, methyl or ethyl; R4 is H, methyl or ethyl; and X- is a monovalent anion, preferably a halide ion; (ii) an alkyl amine oxide nonionic surfactant having an alkyl moiety having an average carbon chain length of 8 to 10 carbon atoms; and (iii) an anionic surfactant having the following general formula:

[0018] R'-X2 - Y +

[0019] Where R' is a straight or branched, saturated or unsaturated alkyl or olefin chain with an average chain length of 8 to 10 carbon atoms, X2 - It is a sulfate group, and Y + It is a cationic balanced ion, preferably selected from sodium, potassium, ammonium and substituted ammonium; wherein the cationic surfactant, the nonionic surfactant and the anionic surfactant are present in the surfactant blend in a molar ratio of about 0.25-1.0:0.25-1.0:0.25-1.0. Attached Figure Description

[0020] Figure 1 This is a graph showing the surface tension vs. concentration distribution of the surfactant blends of this technology. Detailed Implementation

[0021] While the technology described herein will be described in conjunction with one or more preferred embodiments, those skilled in the art will understand that the technology is not limited to those specific embodiments. Rather, the technology described herein includes all alternatives, modifications, and equivalents that may be included within the spirit and scope of the appended claims.

[0022] As used herein, the term “substantially free of fluorocarbons” means that the concentrate or composition contains no more than 0.01 wt% of fluorocarbons.

[0023] As used herein, “fire extinguishing foam concentrate” refers to a blend of aqueous surfactants with a surfactant concentration of approximately 25% to approximately 38% by weight of the concentrate.

[0024] As used herein, "fire extinguishing foam composition" refers to an aqueous composition comprising a blend of surfactants and additional components typically used in fire extinguishing applications. The fire extinguishing foam composition is intended to be mixed with a diluent such as water to a strength suitable for fire extinguishing applications.

[0025] As used herein, "diluent" or "carrier" means a liquid substance or mixture of substances that can be used as a delivery medium or carrier to prepare or dilute the fire extinguishing foam concentrate or composition of the present invention. A diluent may be, for example, water.

[0026] "About" means + / - 10% of the reference value. In some implementations, "about" means + / - 5% of the reference value, or + / - 4% of the reference value, or + / - 3% of the reference value, or + / - 3% of the reference value, or + / - 2% of the reference value, or + / - 1% of the reference value.

[0027] This invention generally relates to surfactant blends for use in aqueous fire extinguishing foam concentrates and compositions, particularly Class B fire extinguishing foam compositions. The surfactant blends comprise a specific molar ratio of a specific quaternary ammonium cationic surfactant, a specific alkyl amine oxide nonionic surfactant, and a specific alkyl sulfate anionic surfactant. An important aspect of this technology is that the surfactants in the surfactant blend have an average hydrophobic alkyl or alkylene carbon chain length of 8 to 10 carbon atoms. In other words, the average value of all hydrophobic alkyl or alkylene chains of all surfactants in the surfactant blend is 8 to 10 carbon atoms. In some embodiments, each of the quaternary ammonium cationic surfactant, amine oxide nonionic surfactant, and alkyl sulfate anionic surfactant components in the surfactant blend has a carbon chain length in the range of 8 to 10 carbon atoms. In other embodiments, the quaternary ammonium cationic surfactant, amine oxide nonionic surfactant, and alkyl sulfate anionic surfactant may have a hydrophobic alkyl or alkylene portion with a carbon chain length greater than 10 or less than 8 carbon atoms, provided that the average value of the hydrophobic alkyl or alkylene chains of all surfactants in the surfactant blend is in the range of 8 to 10 carbon atoms.

[0028] Preferably, the surfactants particularly selected in the blend are at least one quaternary ammonium cationic surfactant having one or two carbon chains with an average carbon chain length of 8 to 10 carbon atoms, at least one amine oxide nonionic surfactant having an alkyl moiety with a carbon chain length of 8 to 10 carbon atoms, and at least one alkyl sulfate anionic surfactant with a carbon chain length of 8 to 10 carbon atoms. The selected surfactants with these specific carbon chain lengths work synergistically to provide a balance of physical properties, making the surfactant blends particularly suitable for Class B fire extinguishing foams. Specifically, the aqueous solution containing the surfactant blend has a relatively low surface tension (less than 25.5 mN / m), a moderate interfacial tension between the aqueous and oil phases (between 0.2 and 3.5 mN / m), and a relatively fast dynamic surface tension that can reach mesoscopic equilibrium surface tension within about 100 ms. The low surface tension of the composition facilitates the spreading of the foam on hydrocarbon surfaces. Moderate or moderate interfacial tension between the aqueous and hydrocarbon phases is desirable to prevent hydrocarbon injection into the foam and impart flammability. Rapid dynamic surface tension is a measure of how quickly a surfactant reduces surface tension and is considered an indicator of how quickly a foam can coat a surface.

[0029] Unbound by any particular theory, it is believed that a specific combination of specific surfactants in specific amounts provides the desired combination of relatively low surface tension, moderate interfacial tension between the aqueous and oil phases, and rapid dynamic surface tension. If the average hydrophobic carbon chain length of one or more surfactants in the surfactant blend is not in the range of 8 to 10 carbon atoms, such that the total average length of all hydrophobic alkyl or alkylene chains in the surfactant blend is not in the range of 8 to 10 carbon atoms, the resulting concentrate or composition may not provide the desired combination of properties. Similarly, compositions using different surfactant components or omitting one of the surfactant components may not provide the desired combination of properties.

[0030] Quaternary ammonium cationic surfactants

[0031] The quaternary ammonium compounds applicable to this article have the following general formula:

[0032]

[0033] R1 is a straight or branched, saturated or unsaturated alkyl or olefin chain with an average carbon chain length of 8 to 10 carbon atoms.

[0034] R2 is H or a straight or branched, saturated or unsaturated alkyl or olefin chain having 1 to 10 carbon atoms, preferably 1 carbon atom.

[0035] R3 is H, methyl, or ethyl;

[0036] R4 is H, methyl, or ethyl; and

[0037] X – It is a monovalent anion equilibrium ion, preferably a halide ion, and most preferably Cl. - or Br - .

[0038] Exemplary quaternary ammonium compounds within the general formula include alkyl (C8-C10)trimethylammonium halides and dialkyl (C8-C10)dimethylammonium halides. Quaternary ammonium compounds may have some R1 carbon chain lengths of more than 10 carbons or less than 8 carbons, provided that the average chain length of the hydrophobic alkyl or alkylene chains in the surfactant blend is 8 to 10 carbon atoms. Specific quaternary ammonium salts include decyltrimethylammonium chloride, decyltrimethylammonium bromide, octyltrimethylammonium chloride, octyltrimethylammonium bromide, and disedecyldimethylammonium chloride. Quaternary ammonium compounds need not be a single entity, but may be a blend of two or more quaternary ammonium compounds.

[0039] Amine oxide nonionic surfactant

[0040] The fire-extinguishing foam concentrate of this technology also includes at least one amine oxide nonionic surfactant having a hydrophobic alkyl moiety having an average of 8 to 10 carbon atoms and two moieties having 1 to 3 carbon atoms, preferably 1 carbon atom. The C8-C10 alkyl moieties can be straight-chain or branched. The amine oxide can be a mixture of alkyl amine oxides with different chain lengths, provided that the average chain length of the longer alkyl moieties is 8 to 10 carbon atoms. Alternatively, the longer alkyl or alkylene moieties can have a carbon chain length greater than 10 or less than 8, provided that the average chain length of all hydrophobic alkyl or alkylene chains present in the surfactant blend is 8 to 10 carbon atoms. Suitable amine oxides for this technology include octyl dimethyl amine oxide and decyl dimethyl amine oxide. Combinations of amine oxides can also be used.

[0041] Alkyl sulfate anionic surfactants

[0042] In addition to cationic quaternary ammonium compounds and amine oxide nonionic surfactants, the fire extinguishing foam concentrate of the present invention also includes at least one alkyl sulfate anionic surfactant having the following general formula:

[0043] R'-X2 - Y +

[0044] Where R' is a straight-chain or branched, saturated or unsaturated alkyl or alkylene group with an average carbon chain length of 8 to 10 carbon atoms; X2 - It is sulfate; and Y + It is a monovalent or divalent cation balance ion. Preferably, the balance ion is selected from sodium, potassium, ammonium, and substituted ammonium, such as monoethanolamine, diethanolamine, and triethanolamine. The alkyl sulfate may have a carbon chain length of more than 10 carbons or less than 8 carbons, provided that the average chain length of all hydrophobic alkyl or alkylene chains present is 8 to 10 carbon atoms. Alkyl sulfates suitable for this technology include octyl sulfate, decyl sulfate, or combinations thereof, such as POLYSTEP® B25 (sodium decyl sulfate) and POLYSTEP® B29 (sodium octyl sulfate), available from Stepan Company, Northbrook, Illinois.

[0045] Cationic surfactants, nonionic surfactants, and anionic surfactants are present in the surfactant blend in a molar ratio of 0.25-1.0:0.25-1.0:0.25-1.0. In some embodiments, the molar ratio is 1:1:1. The surfactant blend may comprise 25% to 38% by weight of the fire extinguishing foam concentrate, with the remainder comprising a liquid carrier, preferably water. Alternatively, the surfactant blend may comprise about 30% to about 35% by weight of the fire extinguishing foam concentrate. The surfactant blend is prepared by mixing the surfactants together in a liquid carrier such that the nonionic surfactant is always present. Standard mixing equipment is acceptable for preparing the fire extinguishing foam concentrate.

[0046] liquid carrier

[0047] The fire-extinguishing foam concentrate of this technology is in liquid form and includes a carrier in addition to cationic quaternary ammonium compounds, amine oxide nonionic surfactants, and alkyl sulfate anionic surfactants. Water is a typical carrier and can be tap water, deionized water, purified water, or a combination thereof. Optionally, a water-miscible solvent, such as an alcohol or glycol ether, may be included in the liquid carrier, although water is preferably the only liquid carrier of the fire-extinguishing foam concentrate.

[0048] Fire extinguishing foam composition

[0049] Fire extinguishing foam concentrates can be combined with additional liquid carriers (such as water) and other components known in the art (such as thickeners, foam stabilizers, polymers, or other functional ingredients) to form fire extinguishing foam compositions. Thickeners that can be used include polysaccharides, such as cellulose and cellulose materials, and gums, such as guar gum, xanthan gum, gum arabic, and gellan gum. Polymers that can be used are water-soluble or water-dispersible polymers. Examples of such polymers include polyacrylamide, polyacrylic acids, vinyl acrylates, vinyl acetate, and polyurethanes. Water can be used alone as a carrier or in combination with other suitable carriers, such as water-miscible solvents, such as alcohols or glycol ethers. By weight of the total fire extinguishing foam composition, the liquid carrier typically comprises about 50% to about 80% by weight, or about 60% to about 75% by weight, and surfactants and additional components comprise about 20% to about 50% by weight, or about 25% to about 40% by weight. By weight of the fire extinguishing foam composition, the surfactant blend may comprise about 0.5% to about 12% by weight.

[0050] How to use

[0051] Fire extinguishing foam compositions incorporating surfactant blends of this technology are designed to be mixed with a diluent and foamed to provide a fire extinguishing composition that can be applied directly to a fire. The diluent is typically water and can be fresh water, municipal water, brine, seawater, or a combination thereof. During dilution, the fire extinguishing foam composition can be mixed into a pressurized or flowing stream of water, such as through an in-line injector. The fire extinguishing foam composition can be aerated, for example, through a nozzle to form foam applied to the surface of a fire or flammable hydrocarbon liquid. Typically, fire extinguishing foam compositions are defined as 3% or 6% concentrates, meaning they are intended to be diluted to 3% or 6% by volume in a diluent via an injector. For example, 3% of the composition is mixed with 97% by volume of the diluent, and 6% of the composition is mixed with 94% by volume of the diluent to obtain a composition for use with dilution. It should be understood that other dilution amounts can be used with the fire extinguishing foam composition, and the concentration of the solid components in the fire extinguishing foam composition can be adjusted accordingly to provide an effective amount of solids when using the dilution.

[0052] The fire extinguishing foam concentrate and composition of this invention can be used to extinguish Class B fires. For example, the fire extinguishing foam concentrate and composition can be used to extinguish hydrocarbon fires, wherein the hydrocarbon is oil, fuel oil, diesel, kerosene, hexane, or cyclohexane. It is contemplated that the fire extinguishing foam concentrate of this invention can be used in any of the six types of concentrates defined by UL 162 as low-expansion foam concentrates.

[0053] The presently described technology and its advantages will be better understood by referring to the following embodiments. These embodiments are provided to describe specific implementations of the technology. The provision of these specific embodiments is not intended to limit the scope and spirit of the technology. Those skilled in the art will understand that the full scope of the presently described technology includes the subject matter defined by the appended claims, as well as any alterations, modifications, or equivalents of those claims.

[0054] Example

[0055] Example 1: Surfactant blend

[0056] Concentrated aqueous compositions comprising different surfactant blends of the present technology and comparative surfactant blends are prepared by combining cationic, anionic, and nonionic (or amphoteric) surfactants in water, such that the nonionic (or amphoteric) surfactant is always present in the composition. The surfactant concentration in each composition is about 35% by weight, and the molar ratio of the surfactants in each composition is about 1:1:1. Table 1 shows the surfactant components in compositions 1 and 2 of the present technology, and the surfactant components in comparative compositions 1-5. For the comparative compositions, the anionic surfactant or nonionic component is not according to the present technology.

[0057] Table 1

[0058]

[0059] Table 1 shows that replacing the quaternary ammonium compound and amine oxide of the present technology with a quaternary ammonium compound having an alkyl chain length of 16 carbon atoms and an amine oxide having an alkyl chain length of 14 carbon atoms respectively (Comparative Example 4), or replacing the alkyl amine oxide of the present technology with betaine (Comparative Example 5), produces compositions that do not have acceptable physical or chemical stability.

[0060] Example 2: Tension Measurement Test

[0061] The surface tension (ST) of each composition in Example 1, as a clarified liquid, was evaluated in deionized (DI) water and simulated seawater (prepared according to ASTM D1141). The interfacial tension (IFT) of each composition against kerosene and cyclohexane was also evaluated. Compositions were diluted to 0.1% by weight solutions for testing. ST was determined using a Kibron microtrough. IFT measurements were determined using a Kruss Drop Shape Analysis System DSA10 via the pendant drop method. In this method, a denser droplet is formed at the end of a capillary tip, pointing downwards within a less dense phase. The droplet typically forms at approximately 90% of its detachment volume (from the capillary). The droplet is then digitally imaged. The droplet image is fitted using robust mathematical methods to determine the average curvature of the droplet along its surface at over 300 points.

[0062] The spreading factor Cs for each composition is determined according to the following equation:

[0063] Cs=ST HC -(T HC-AQ +IFT HC-AQ )

[0064] Among them ST HC It is the surface tension of hydrocarbons, T HC-AQ It is the surface tension of the aqueous phase, and IFT HC-AQ This refers to the interfacial tension between the hydrocarbon and aqueous phases. The surface tension should be low (less than 25.5 mN / m) to facilitate foam spreading on the hydrocarbon surface. Spontaneous spreading occurs when the surface energy of the hydrocarbon-air interface is greater than the sum of the surface energy of the water-air interface and the hydrocarbon-water interface. In other words, spontaneous spreading will occur when Cs > 0. Lower IFTs will favor spontaneous spreading. However, if the interfacial tension is too low, the two liquids will tend to emulsify. This can negatively impact AFFF performance because emulsified hydrocarbons are more likely to permeate the aqueous film, resulting in a flammable mixture.

[0065] The following STs are for hydrocarbons: kerosene = 27.0 mN / m, cyclohexane = 25.5 mN / m. Figure 1The surface tension versus concentration curves of compositions 1 and 2 from Example 1 in DI water are shown. Table 2 below shows the results of surface tension, interfacial tension, and spreading coefficient from the tests of the clarified liquid compositions from Example 1.

[0066] Table 2

[0067]

[0068] The results in Table 2 show that only the compositions of this technique possess interfacial tension and spreading coefficients favorable for spontaneous spreading on hydrocarbons. Replacing amine oxide surfactants with alkyl betaine surfactants, or alkyl sulfate anionic surfactants with alkyl sulfonate surfactants, yields compositions with surface tensions higher than 25 mN / m and Cs less than zero. These results indicate that surfactant blends containing surfactants other than those selected in this technique have insufficient surface properties for spontaneous spreading on hydrocarbon surfaces.

[0069] Example 3: Foam Spreading on Kerosene

[0070] The foam spreading of compositions 1 and 2 from Example 1 on kerosene was evaluated. For the test, each composition (300 μL) was diluted in 8-dram vials with DI water or simulated seawater (4700 μL). The vials were vigorously shaken to generate foam, which was then applied to the kerosene surface within 30 seconds of generation. The foam was transferred to the surface in 2 × 8.5 mL portions using a large disposable pipette with the tip cut off. The kerosene surface was 10 mL of kerosene in a 60 mm diameter aluminum weighing pan. The foam was observed, and qualities such as ease of spreading, foam quality, robustness to physical damage, and lifespan were recorded.

[0071] The foams from both Composition 1 and Composition 2 spread readily on the kerosene surface and persisted for up to 30 minutes. When the foam was agitated with a disposable pipette, it readily sealed around the agitation, indicating resistance to physical damage. The foams also did not emulsify the kerosene. After the foam was drained into the kerosene pan, both the kerosene and aqueous phases were clear, indicating no emulsification.

[0072] Example 4: Vapor Permeation

[0073] Vapor permeation tests were performed on compositions 1 and 2 of Example 1 to determine the sealing performance of the foam in flammable hydrocarbon vapors. For the test, each composition (300 μL) was diluted in 8-dry-pan vials with DI water or simulated seawater (4700 μL). The vials were shaken vigorously to generate foam, which was then applied to a cyclohexane surface within 30 seconds of generation. The foam was transferred to the surface in 2 × 8.5 mL portions using a large disposable pipette with the tip cut off. The hydrocarbon surface was 2 mL of cyclohexane in a 60 mm diameter aluminum weighing pan. A flame from a cigarette lighter was held approximately 2 cm above the surface, and the result was observed. If no ignition occurred within 30 seconds, the flame was removed, the surface was disturbed with a disposable pipette, and the flame was reapplied.

[0074] Both Composition 1 and Composition 2 produce foams that readily spread on a cyclohexane surface and are initially sealed in vapor. The foam only breaks and ignites after numerous mechanical disturbances.

[0075] Example 5: Foam Lifespan

[0076] Compositions 1 and 2 from Example 1 were evaluated to determine their foam lifetime and robustness on kerosene compared to sodium lauryl sulfate (SLS) and alkyl ether ammonium sulfate (CEDEPAL FA-406) surfactants known to have foaming capabilities. For the tests, compositions at concentrations of 0.5 wt%, 3 wt%, and 6 wt% in DI water were foamed using an air spray foam pump matrix (43 mm neck, L11 engine, 0.75 output) to produce foam. The foam pump had an air:liquid ratio of 11:1, with a liquid dosage of 0.75 ml. The generated foam was uniformly dispersed into a 60 mm diameter aluminum weighing pan containing 4 mL of Aldrich grade kerosene and immediately covered with a crystallizing glass pan to prevent foam evaporation or breakage. The test was timed and completed when a breakout occurred. Breakout was defined as the time taken for the foam to open or unblock, allowing hydrocarbons to become visible. The results are shown in Table 3.

[0077] Table 3

[0078]

[0079] Compared to sodium lauryl sulfate and alkyl ether ammonium sulfate surfactants, the foams of compositions 1 and 2 exhibit significantly longer foaming time and demonstrate robustness with surfactant loadings as low as 0.5% by weight.

[0080] Example 6: Dynamic Surface Tension

[0081] The dynamic surface tension (DST) of a 0.1 wt% surfactant solution relative to DI water at 25 °C was determined using a Krüss BP100 bubble pressure tensiometer. The surfactant solutions tested were surfactant blends consisting of compositions of decyltrimethylammonium chloride cationic surfactant, sodium decyl sulfate anionic surfactant, and octyl dimethylamine oxide nonionic surfactant in different molar ratios within the range of 0.25–1:0.25–1:0.25–1, as well as individual cationic, anionic, and nonionic surfactants, each used as a single surfactant. Surfactant blend samples were prepared according to this technique, while single surfactant samples were comparative examples. Bubble pressure measurement parameters were: capillary diameter 0.356 mm, detection speed 20 mm / min, and detection sensitivity 50 Pa. The DST results are shown in Table 4.

[0082] Table 4

[0083]

[0084] The results show that, compared with samples containing a single surfactant, samples containing surfactant blends of this technology rapidly approach lower surface tension.

[0085] This technology will now be described in complete, clear, and concise terminology to enable those skilled in the art to practice it. It should be understood that the foregoing describes preferred embodiments of the technology and modifications may be made thereto without departing from the spirit or scope of the technology as set forth in the appended claims. Furthermore, the examples provided are not exhaustive but rather illustrative of several embodiments falling within the scope of the claims.

Claims

1. Fire extinguishing foam concentrate, which includes: (a) a surfactant blend comprising approximately 25% to approximately 38% by weight of the concentrate, the surfactant blend comprising: (i) Cationic surfactants having the following general formula: R1 is a straight or branched, saturated or unsaturated alkyl or olefin chain with an average chain length of 8 to 10 carbon atoms. R2 is H or a straight or branched, saturated or unsaturated alkyl or olefin chain having 1 to 10 carbon atoms; R3 is H, methyl, or ethyl; R4 is H, methyl, or ethyl; and X – It is a monovalent anion equilibrium ion, preferably a halide ion, with Cl being the most preferred. - or Br - ; (ii) Alkyl oxide amine nonionic surfactants having an alkyl moiety having an average carbon chain length of 8 to 10 carbon atoms; (iii) Anionic surfactants having the following general formula: R’-X2 - Y + Where R' is a straight or branched, saturated or unsaturated alkyl or olefin chain with an average chain length of 8 to 10 carbon atoms, X2 - It is a sulfate group, and Y + It is a cation balance ion, preferably selected from sodium, potassium, ammonium and substituted ammonium; The cationic surfactant, the nonionic surfactant, and the anionic surfactant are present in the surfactant blend in a molar ratio of approximately 0.25-1.0 : 0.25-1.0 : 0.25-1.0; and (b) Total weight of water to concentrate 100%.

2. The fire extinguishing foam concentrate according to claim 1, wherein the cationic surfactant is selected from: octyltrimethylammonium chloride, octyltrimethylammonium bromide, decyltrimethylammonium chloride, decyltrimethylammonium bromide, and combinations thereof.

3. The fire extinguishing foam concentrate according to claim 1 or 2, wherein the nonionic surfactant is selected from: octyl dimethylamine oxide, decyl dimethylamine oxide, and combinations thereof.

4. The fire extinguishing foam concentrate according to any one of claims 1 to 3, wherein the anionic surfactant is selected from: octyl sulfate, decyl sulfate, and combinations thereof.

5. The fire extinguishing foam concentrate according to any one of claims 1 to 4, wherein the fire extinguishing foam concentrate is substantially free of or does not contain fluorinated compounds.

6. The fire extinguishing foam concentrate according to any one of claims 1 to 5, wherein the amount of the surfactant blend is from 30% by weight to about 35% by weight of the concentrate.

7. The fire extinguishing foam concentrate according to any one of claims 1 to 6, wherein the molar ratio of the surfactants in the surfactant blend is about 1:1:

1.

8. The fire extinguishing foam concentrate according to any one of claims 1 to 7, wherein the fire extinguishing foam concentrate reduces the surface tension of the aqueous solution to 25.5 mN / m or less.

9. The fire extinguishing foam concentrate according to any one of claims 1 to 8, wherein the fire extinguishing foam concentrate or its aqueous dilution can reach mesoscopic equilibrium surface tension within about 100 ms.

10. A fire extinguishing foam composition comprising the fire extinguishing foam concentrate according to any one of claims 1 to 9.

11. The fire extinguishing foam composition of claim 10, wherein the surfactant blend of the fire extinguishing foam concentrate is present in the fire extinguishing foam composition in an amount of 0.5% to 12% by weight.

12. A fire extinguishing foam composition comprising: (a) a surfactant blend comprising about 0.5% to about 12% by weight of the composition, said surfactant blend containing (i) Cationic surfactants having the following general formula: R1 is a straight or branched, saturated or unsaturated alkyl or olefin chain with an average chain length of 8 to 10 carbon atoms. R2 is H or a straight or branched, saturated or unsaturated alkyl or olefin chain having 1 to 10 carbon atoms; R3 is H, methyl, or ethyl; R4 is H, methyl, or ethyl; and X – It is a monovalent anion equilibrium ion, preferably a halide ion, with Cl being the most preferred. - or Br - ; (ii) Alkyl oxide amine nonionic surfactants having an alkyl moiety having an average carbon chain length of 8 to 10 carbon atoms; (iii) Anionic surfactants having the following general formula: R’-X2 - Y + Where R' is a straight or branched, saturated or unsaturated alkyl or olefin chain with an average chain length of 8 to 10 carbon atoms, X2 - It is a sulfate group, and Y + It is a cation balance ion, preferably selected from sodium, potassium, ammonium and substituted ammonium; The cationic surfactant, the nonionic surfactant, and the anionic surfactant are present in the surfactant blend in a molar ratio of about 0.25-1.0 : 0.25-1.0 : 0.25-1.

0. b) at least one additive selected from thickeners, stabilizers and polymers; and c) water to a total of 100% by weight of the composition.

13. The fire extinguishing foam composition according to claim 12, wherein the cationic surfactant is selected from: octyltrimethylammonium chloride, octyltrimethylammonium bromide, decyltrimethylammonium chloride, decyltrimethylammonium bromide, and combinations thereof.

14. The fire extinguishing foam composition according to claim 12 or 13, wherein the nonionic surfactant is selected from: octyl dimethylamine oxide, decyl dimethylamine oxide, and combinations thereof.

15. The fire extinguishing foam composition according to any one of claims 12-14, wherein the anionic surfactant is selected from octyl sulfate, decyl sulfate, and combinations thereof.

16. The fire extinguishing foam composition according to any one of claims 12-15, wherein the fire extinguishing foam composition is substantially free of or does not contain fluorinated compounds.

17. The fire extinguishing foam composition according to any one of claims 12-16, wherein the molar ratio of the surfactants in the surfactant blend is about 1:1:

1.

18. Methods for extinguishing fires, including: (a) Inflate the fire extinguishing foam composition to form aerated fire extinguishing foam; and (b) Applying the inflatable fire extinguishing foam to the surface of a fire or a volatile flammable liquid, wherein the fire extinguishing foam composition comprises water and a surfactant blend of about 0.5% to about 12% by weight of the composition, the surfactant blend comprising: (i) Cationic surfactants having the following general formula: R1 is a straight or branched, saturated or unsaturated alkyl or olefin chain with an average chain length of 8 to 10 carbon atoms. R2 is H or a straight or branched, saturated or unsaturated alkyl or olefin chain having 1 to 10 carbon atoms; R3 is H, methyl, or ethyl; R4 is H, methyl, or ethyl; and X – It is a monovalent anion equilibrium ion, preferably a halide ion, with Cl being the most preferred. - or Br - ; (ii) alkyl amine oxide nonionic surfactants having an alkyl moiety having an average carbon chain length of 8 to 10 carbon atoms; and (iii) Anionic surfactants having the following general formula: R’-X2 - Y + Where R' is a straight or branched, saturated or unsaturated alkyl or olefin chain with an average chain length of 8 to 10 carbon atoms, X2 - It is a sulfate group, and Y + It is a cation balance ion, preferably selected from sodium, potassium, ammonium and substituted ammonium; The cationic surfactant, the nonionic surfactant, and the anionic surfactant are present in the surfactant blend in a molar ratio of about 0.25-1.0 : 0.25-1.0 : 0.25-1.

0.

19. The method of claim 18, further comprising, prior to inflation, mixing the fire extinguishing foam composition with a diluent to dilute the fire extinguishing foam composition.

20. The method of claim 19, wherein the diluent comprises municipal water, brine, brine, or a mixture thereof.

21. The method according to any one of claims 18-20, wherein the cationic surfactant is selected from octyltrimethylammonium chloride, octyltrimethylammonium bromide, decyltrimethylammonium chloride, decyltrimethylammonium bromide, and combinations thereof.

22. The method according to any one of claims 18-21, wherein the nonionic surfactant is selected from octyl dimethylamine oxide, decyl dimethylamine oxide, and combinations thereof.

23. The method according to any one of claims 18 to 22, wherein the anionic surfactant is selected from octyl sulfate, decyl sulfate, and combinations thereof.

24. The method according to any one of claims 18 to 23, wherein the fire extinguishing foam composition does not contain fluorinated compounds.

25. The method according to any one of claims 18-24, wherein the molar ratio of the surfactants in the surfactant blend is about 1:1:1.

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