Crosslinked xanthan for isopropanol stability performance

Abstract

An aqueous fire-fighting foam concentrate includes xanthan gum crosslinked by a metal salt, a surfactant component, and water.

Description

CROSSLINKED XANTHAN FOR ISOPROPANOL STABILITY PERFORMANCECROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 580,919 filed September 6, 2023, which is hereby incorporated by reference, in its entirety for any and all purposes.BACKGROUND

[0002] Firefighting foams are often able to fight Class A and Class B fires. Class A fires are those involving combustible material such as paper, wood, etc. and may be fought by quenching and cooling with large quantities of water or solutions containing water. Class B fires are those involving flammable liquid fuels, gasoline, and other hydrocarbons and are difficult to extinguish. Most flammable liquids exhibit high vapor pressure along with low fire and flash points. This typically results in a wide flammability range. In this type of fire, the use of water as the sole firefighting agent is generally ineffective because the only means of fighting fire with water is through cooling.

[0003] Conventional foam-forming firefighting compositions commonly include fluorinated surfactants. There is a strong desire in the marketplace to replace these fluorinated firefighting products with non-fluorinated products. There is, therefore, a continuing need to produce non-fluorinated firefighting compositions, also known as synthetic fluorine-free foams (“SFFFs”) that may be deployed to fight Class A and Class B fires.SUMMARY

[0004] In one aspect, aqueous fire-fighting foam concentrates are provided that may be diluted with an aqueous diluent to provide a foam precursor composition, which may in turn be aerated to form a firefighting foam. The present aqueous fire-fighting foam concentrates include a xanthan gum crosslinked by a metal salt, a surfactant component, andwater. The aqueous fire-fighting foam concentrates may further include a sugar component, an organic solvent, or a combination thereof.

[0005] In some embodiments, the xanthan gum is deacylated or partially deacylated. In some embodiments, the metal salt includes a divalent ion. In some embodiments, the divalent ion is selected from Ca2+, Ba2+, Sr2*, Zn2+, or a mixture of any two or more thereof. In some embodiments, the metal salt is selected from calcium chloride, calcium acetate, strontium chloride, strontium acetate, barium chloride, barium acetate, zinc chloride, or a mixture of any two or more thereof.

[0006] In some embodiments, the surfactant component includes a non-ionic surfactant, an anionic surfactant, an amphoteric surfactant, or a mixture of any two or more thereof. In some embodiments, the non-ionic surfactant includes an alkyl polyglycoside, an aliphatic alcohol-based non-ionic surfactant, or a mixture of any two or more thereof. In some embodiments, the non-ionic surfactant includes an alkyl polyglucoside, an aliphatic alcohol, an aliphatic alcohol ethoxylate, or a mixture of any two or more thereof. In some embodiments, the anionic surfactant includes an alkyl sulfate salt, an alkyl sulfonate salt, an alkyl ether sulfate surfactant, an alkyl ether sulfonate surfactant, or a mixture of any two or more thereof. In some embodiments, the amphoteric surfactant is selected from an alkylamidoalkyl hydroxysultaine, an alkylamidoalkyl betaine, an alkyl sulfobetaine surfactant, an alkyl betaine surfactant, or a mixture of any two or more thereof.

[0007] In some embodiments, the aqueous fire-fighting foam concentrate further includes a sugar component, an organic solvent, or a combination thereof. In some embodiments, the sugar component includes a monosaccharide sugar, a disaccharide sugar, a sugar alcohol, or a mixture of any two or more thereof. In some embodiments, the sugar component includes glucose, fructose, mannose, sucrose, maltose, lactose, lactulose, trehalose, cellobiose, chitobiose, xylose, sorbitol, mannitol, or a combination of any two or more thereof. In some embodiments, the organic solvent includes an alkylene glycol, a glycerol, a water-soluble polyethylene glycol, a glycol ether, or a mixture of any two or more thereof.

[0008] In another aspect, provided is an aqueous fire-fighting foam concentrate including a xanthan gum crosslinked by a metal salt; a surfactant component including a nonionic surfactant, an anionic surfactant, an amphoteric surfactant, or a mixture of any two or more thereof; an organic solvent; a sugar component; and water.

[0009] In another aspect, provided is an aqueous fire-fighting foam concentrate including: about 0.5 to 5 wt% of xanthan gum crosslinked by a metal salt; about 0.1 to 15 wt% of the metal salt; about 1 to 30 wt% of a non-ionic surfactant; and at least about 30 wt% water. In some embodiments, the aqueous fire-fighting concentrate further includes about 2 to 20 wt% of an anionic surfactant; about 1 to 10 wt% of an amphoteric surfactant; about 0.5 to 20 wt% of an organic solvent; and about 5 to 25 wt% of a sugar component.

[0010] In yet another aspect, provided is a method of forming a firefighting foam, the method includes mixing any one of the aqueous fire-fighting concentrates described herein with an aqueous diluent to form a foam precursor solution and aerating the foam precursor solution to form the firefighting foam. In some embodiments, the aqueous diluent is selected from the group consisting of fresh water, brackish water, sea water, or a mixture of two or more thereof. In some embodiments, a method of extinguishing a fire is provided, the method including: administering a firefighting foam as described herein to the fire. In some embodiments, the fire is an isopropyl alcohol fire.DETAILED DESCRIPTION

[0011] Various embodiments are described hereinafter. It should be noted that the specific embodiments are not intended as an exhaustive description or as a limitation to the broader aspects discussed herein. One aspect described in conjunction with a particular embodiment is not necessarily limited to that embodiment and may be practiced with any other embodiment s).

[0012] As used herein, “about” will be understood by persons of ordinary skill in the art and will vary to some extent depending upon the context in which it is used. If there are uses of the term which are not clear to persons of ordinary skill in the art, given the context in which it is used, “about” will mean up to plus or minus 10% of the particular term.

[0013] The use of the terms “a” and “an” and “the” and similar referents in the context of describing the elements (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein may be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the embodiments and does not pose a limitation on the scope of the claims unless otherwise stated. No language in the specification should be construed as indicating any non-claimed element as essential.

[0014] In one aspect, the aqueous fire-fighting foam concentrates of the present disclosure include xanthan gum crosslinked by a metal salt; a surfactant component; and water.

[0015] Typically, nonfluorinated foams use two or more different polysaccharides to achieve good fire performance; however, the present aqueous fire-fighting concentrates include only one polysaccharide. In some embodiments, the xanthan gum includes deacylated or partially deacylated xanthan gum. The aqueous fire-fighting foam concentrates may include about 0.5 to 5 wt% of xanthan gum. In some embodiments, the aqueous firefighting foam concentrates may include about 0.5 wt%, about 1 wt%, about 2 wt%, about 3 wt%, about 4 wt%, or about 5 wt% of the xanthan gum.

[0016] In some embodiments, the metal salts used in the present aqueous fire-fighting concentrates may include a divalent ion. Examples of divalent ions for use in the present aqueous fire-fighting concentrates include, but are not limited to, Ca2+, Ba2+, Sr2+, Zn2+, or a mixture of any two or more thereof. Examples of metal salts for use in the present aqueous fire-fighting concentrates include, but are not limited to, calcium chloride, calcium acetate, strontium chloride, strontium acetate, barium chloride, barium acetate, zinc chloride, or a mixture of any two or more thereof. The aqueous fire-fighting foam concentrates may include about 0.1 to 15 wt%, about 0.5 to 15 wt%, about 1 to 15 wt%, about 5 to 15 wt%, about 10 to15 wt%, about 0.1 to 10 wt%, or about 0.1 to 5 wt% of the metal salt. In some embodiments, the aqueous fire-fighting foam concentrates include about 0.1 wt%, about 0.5 wt%, about 1 wt%, about 2 wt%, about 3 wt%, about 4 wt%, about 5 wt%, about 6 wt%, about 7 wt%, about 8 wt%, about 9 wt%, about 10 wt%, about 11 wt%, about 12 wt%, about 13 wt%, about 14 wt%, or about 15 wt% of the metal salt.

[0017] In some embodiments, the surfactant component may include a non-ionic surfactant, an anionic surfactant, an amphoteric surfactant, or a mixture of two or more thereof.

[0018] In some embodiments, the nonionic surfactant may include an alkyl polyglycoside, an aliphatic alcohol-based nonionic surfactant, or a mixture thereof. In some embodiments, the non-ionic surfactant may include alkyl glycoside, an alkyl polyglucoside, an aliphatic alcohol, an aliphatic alcohol ethoxylate, or a mixture of two or more thereof.

[0019] In some embodiments, the alkyl glycoside or alkyl polyglycoside (APG) each may include a Cs-Ci6 alkyl group. In some embodiments, the sugar-based surfactant may include octyl glucoside, decyl glucoside, lauryl glucoside, decyl maltoside, dodecyl maltoside, or an alkyl polyglucoside. In some embodiments, the alkyl polyglucoside is a Cs- alkyl polyglucoside.

[0020] In some embodiments, the fire-fighting concentrate may include an aliphatic alcohol -based nonionic surfactant including an aliphatic alcohol having 8 to 14 carbon atoms and / or an aliphatic alcohol ethoxylate having 10 to 16 carbon atoms in its alcohol portion. The aliphatic alcohol ethoxylate may have an average degree of polymerization (i.e., the average number of ethylene oxide units) of about 0.7-2.0. In some embodiments, the aliphatic alcohol ethoxylate has an average degree of polymerization of no more than about 1.5, no more than about 1.2, or no more than about 1.0. Aliphatic alcohols, which include a linear Cs-u-aliphatic alcohol, such as a Cs-u-fatty alcohol, may be used as a nonionic surfactant in the present firefighting compositions. Non-limiting examples of such alcohols include one or more of octyl alcohol, decyl alcohol, lauryl alcohol, and myristyl alcohol. The firefighting composition may include an aliphatic alcohol ethoxylate having an average of no more than about 2 ethylene oxide units. In some embodiments, the aliphatic alcohol portionof such ethoxylates may include about 10 to 16 carbon atoms. Non-limiting examples include decyl alcohol ethoxylates, lauryl alcohol ethoxylates and / or myristyl alcohol ethoxylates. In some embodiments, the alcohol ethoxylates have an average of no more than about 2 ethylene oxide units, no more than about 1.5 ethylene oxide units, no more than about 1.2 ethylene oxide units, or no more than about 1 ethylene oxide units. In some embodiments, the aliphatic alcohol ethoxylate may include an ethoxylate of a linear Cs-i4- aliphatic alcohol having no more than about 1.2 ethylene oxide units.

[0021] The aqueous fire-fighting foam concentrates may may include about 1 to 30 wt%, about 1 to 20 wt%, about 1 to 10 wt%, about 10 to 20 wt%, about 10 to 30 wt% of the non-ionic surfactant. In some embodiments, the aqueous fire-fighting foam concentrates may include about 1 wt%, about 2 wt%, about 3 wt%, about 4 wt%, about 5 wt%, about 6 wt%, about 7 wt%, about 8 wt%, about 9 wt%, about 10 wt%, about 11 wt%, about 12 wt%, about 13 wt%, about 14 wt%, about 15 wt%, about 16 wt%, about 17 wt%, about 18 wt%, about 19 wt%, about 20 wt%, about 21 wt%, about 22 wt%, about 23 wt%, about 24 wt%, about 25 wt%, about 26 wt%, about 27 wt%, about 28 wt%, about 29 wt%, or about 30 wt% of the non-ionic surfactant.

[0022] In some embodiments, the present aqueous fire-fighting foam concentrates may include an anionic surfactant. When present in the aqueous fire-fighting concentrate, the anionic surfactants may include an alkyl sulfate surfactant, an alkyl sulfonate surfactant, alkyl ether sulfate surfactant, an alkyl ether sulfonate surfactant, or a mixture of any two or more thereof. In some embodiments, the anionic surfactant may include an alkyl sulfate surfactant and / or an alkyl sulfonate surfactant. In some embodiments, the alkyl sulfate salt surfactant may include a Cs-i2-alkyl sulfate salt. Non-limiting examples of the Cs-i2-alkyl sulfate salt include a dodecyl sulfate salt, a decyl sulfate salt, an octyl sulfate salt, or a mixture of any two or more thereof. In some embodiments, the alkyl sulfate salt may include an alkyl sulfate sodium salt, such as a sodium decyl sulfate, sodium octyl sulfate, or a mixture of any two or more thereof. In some embodiments, the alkyl sulfate salt may include an alkyl sulfate ammonium salt, such as an ammonium decyl sulfate, ammonium octyl sulfate, ammonium lauryl sulfate, or a mixture of any two or more thereof. In some embodiments, the anionic surfactant may include a Cs- -alkyl sulfate salt and / or a Cs-i4-alkyl sulfonate salt. In someembodiments, the firefighting composition may further include an anionic surfactant, which may include one or more surfactants selected from Cs-n-alkyl sulfate salts and / or a Cs-i2- alkyl sulfonate salts. As a non-limiting example, one or more of octyl sulfate salts, decyl sulfate salts, dodecyl sulfate salts and tetradecyl sulfate salts may be used as anionic surfactants in the present aqueous firefighting concentrates. The anionic surfactant may be a sodium, potassium and / or ammonium salt.

[0023] In embodiments that include the anionic surfactant, the aqueous firefighting foam concentrate may include about 2 to 20 wt.% of the anionic surfactant. In some embodiments, the aqueous firefighting foam concentrate may include about 2 to 15 wt.%, about 2 to 10 wt.% and, in some instances, about 3 to 10 wt.% of the anionic surfactant. In some embodiments, the aqueous firefighting foam concentrate may include about 2 wt%, about 3 wt%, about 4 wt%, about 5 wt%, about 6 wt%, about 7 wt%, about 8 wt%, about 9 wt%, about 10 wt%, about 11 wt%, about 12 wt%, about 13 wt%, about 14 wt%, about 15 wt%, about 16 wt%, about 17 wt%, about 18 wt%, about 19 wt%, or about 20 wt% of the anionic surfactant.

[0024] In some embodiments, the present aqueous fire-fighting foam concentrates may include an amphoteric surfactant. Examples of the amphoteric surfactants include, but are not limited to, an alkylamidoalkyl betaine surfactant, an alkyl betaine surfactant, an alkyl sulfobetaine surfactant, an alkylamidoalkylene hydroxysultaine surfactant, such as an alkylamidopropyl hydroxysultaine surfactant, or a mixture of two or more thereof. As a nonlimiting example, the firefighting composition may further include an amphoteric surfactant, which may include one or more of a Cs-is-alkylamidopropyl hydroxysultaine surfactant, a Cs- is-alkylamidopropyl betaine surfactant, a Cx-ix-alkyl sulfobetaine surfactant, a Cx-ix-alkyl betaine surfactant, or a mixture of two or more thereof. Non-limiting examples of the alkylamidoalkylene hydroxysultaine surfactant include a Cs-is-alkylamidopropyl hydroxysultaine surfactant, such as a cocamidopropyl hydroxysultaine surfactant, which may include a lauryl amidopropyl hydroxysultaine and a myristylamidopropyl hydroxysultaine. Non-limiting examples of the alkylamidoalkyl betaine surfactant include a Cs-is- alkylamidoalkyl betaine surfactant, such as a cocamidopropyl betaine, a tallowamidopropyl betaine, a lauryl amidopropyl betaine or a myristyl amidopropyl betaine. In someembodiments, the amphoteric surfactant may include a Cs- -alkylamidopropyl hydroxysultaine, such as a cocamidopropyl hydroxysultaine. In some embodiments, the amphoteric surfactant includes lauryl amidopropyl hydroxysultaine and / or my ri sty 1 ami dopropy 1 hydroxy sultaine .

[0025] In embodiments that include the amphoteric surfactant, the aqueous firefighting foam concentrate may include about 1 to 10 wt.% of the amphoteric surfactant. In certain embodiments, the aqueous firefighting foam concentrate may include about 2 to 10 wt.% or about 5 to 10 wt.% of the amphoteric surfactant. In some embodiments, the aqueous firefighting foam concentrate may include about 1 wt%, about 2 wt%, about 3 wt%, about 4 wt%, about 5 wt%, about 6 wt%, about 7 wt%, about 8 wt%, about 9 wt%, or about 10 wt% of the amphoteric surfactant.

[0026] In some embodiments, the aqueous fire-fighting foam concentrates may further include a sugar component, an organic solvent, or a combination thereof.

[0027] Saccharides for use in the present aqueous fire-fighting concentrates are generally simple monosaccharide sugars and may include other carbohydrates, such as common sugar (sucrose / dextrose) derived from sugar cane or sugar beets. Sucrose is a disaccharide composed from the basic, simple sugar molecules glucose and fructose. Mixtures where the majority of the sucrose has been broken down into its monosaccharide components, glucose, and fructose (e.g., invert sugar), are quite suitable for use in the present concentrates. Sucrose is readily available in view of its world production from cane and sugar beet on the order of millions of tons per annum. Those skilled in the art will also be aware that other commercially available simple monosaccharides and related sugar alcohols may be utilized in the present concentrates. Examples of monosaccharides for use in the present concentrates include one or more of glucose, fructose, mannose, xylose, ribose, and galactose. Examples of suitable disaccharides for use in the present foam concentrates include one or more of sucrose, lactose, maltose, trehalose, lactulose, cellobiose, and chitobiose. Examples of suitable sugar alcohols for use in the present concentrates include one or more of a four carbon sugar alcohol, such as erythritol, a five carbon alditol, such as xylitol, a six carbon alditol, such as mannitol and / or sorbitol, and other sugar alcohols, such as isomalt. In some embodiments, the sugar alcohol is one derived from a monosaccharide.

[0028] In some embodiments, the present aqueous fire-fighting foam concentrates may further include a sugar component that may include a monosaccharide sugar, a disaccharide sugar, and / or a sugar alcohol. Examples include, but are not limited to, a sugar component containing one or more of glucose, fructose, mannose, sucrose, lactose, maltose, trehalose, lactulose, cellobiose, chitobiose, xylose, sorbitol, xylitol, and mannitol. In some embodiments, the aqueous fire-fighting foam concentrate may include about 5 to 25 wt.% of the sugar component. In some embodiments, the aqueous fire-fighting foam concentrate may include about 10 to 20 wt.% of the sugar component. In some embodiments, the aqueous fire-fighting foam concentrate may include about 5 wt%, about 6 wt%, about 7 wt%, about 8 wt%, about 9 wt%, about 10 wt%, about 11 wt%, about 12 wt%, about 13 wt%, about 14 wt%, about 15 wt%, about 16 wt%, about 17 wt%, about 18 wt%, about 19 wt%, about 20 wt%, about 21 wt%, about 22 wt%, about 23 wt%, about 24 wt%, or about 25 wt% of the sugar component.

[0029] The present aqueous fire-fighting foam concentrates may further include an organic solvent, which may include one or more of a glycol, a glycol ether, glycerol and a water-soluble polyethylene glycol. Examples of organic solvents include, but are not limited to, diethylene glycol n-butyl ether, dipropylene glycol n-propyl ether, hexylene glycol, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, tripropylene glycol, dipropylene glycol monobutyl ether, dipropylene glycol monomethyl ether, diethylene glycol monobutyl ether, ethylene glycol monobutyl ether, tripropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, glycerol, and mixtures of two or more thereof. In some embodiments, the organic solvent may include a mixture of an alkylene glycol and a glycol ether, such as a glycol butyl ether. In some embodiments, the organic solvent includes an alkylene glycol ether, such as ethylene glycol monoalkyl ether, propylene glycol monoalkyl ether, dipropylene glycol monoalkyl ether, and / or diethylene glycol monoalkyl ether. In some embodiments, the organic solvent includes an alkylene glycol, such as ethylene glycol, propylene glycol, dipropylene glycol and / or diethylene glycol. In some embodiments, the organic solvent may include a mixture of a glycol ether, such as diethylene glycol monobutyl ether, and a glycol, such as ethylene glycol and / or propylene glycol. For example, the organic solvent may include ethylene glycol and diethylene glycol monobutyl ether. Inanother example, the organic solvent includes propylene glycol and diethylene glycol monobutyl ether.

[0030] The aqueous firefighting foam concentrate may include about 0.5 to about 20 wt.%, about 1 to about 20 wt.%, about 1 to about 15 wt.%, or about 2 to about 10 wt.% of the organic solvent. In some embodiments, the aqueous firefighting foam concentrate includes about 1 wt%, about 2 wt%, about 3 wt%, about 4 wt%, about 5 wt%, about 6 wt%, about 7 wt%, about 8 wt%, about 9 wt%, about 10 wt%, about 11 wt%, about 12 wt%, about 13 wt%, about 14 wt%, about 15 wt%, about 16 wt%, about 17 wt%, about 18 wt%, about 19 wt%, or about 20 wt% of the organic solvent.

[0031] In some embodiments, the aqueous firefighting foam concentrate includes an organic solvent including one or more of an alkylene glycol, glycerol, and a glycol ether. The alkylene glycol typically includes propylene glycol and / or ethylene glycol. The glycol ether typically includes ethylene glycol monoalkyl ether, diethylene glycol monoalkyl ether, dipropylene glycol monoalkyl ether, triethylene glycol monoalkyl ether, and 1-butoxyethoxy- 2-propanol. In some embodiments, the organic solvent may be a mixture of alkylene glycol and glycol ether. In some embodiments, the organic solvent may be a mixture of propylene glycol and a glycol ether. In such embodiments, the organic solvent includes the alkylene glycol and glycol ether in a weight ratio of about 0.1 : 1 to about 10: 1 or about 0.2: 1 to about 5: 1. In some embodiments, the organic solvent may be a mixture of propylene glycol and diethylene glycol monobutyl ether.

[0032] As discussed above, the aqueous firefighting foam concentrate includes water. In some embodiments, the water is water from a municipal water source (e.g., tap water). In some embodiments, the water is a purified water, such as purified water that meets the standards set forth in the United States Pharmacopeia, which is incorporated by reference herein in relevant part. In some embodiments, the aqueous firefighting foam composition includes at least about 30 wt.% water, at least about 40 wt.% water, or at least about 50 wt.% water. In some embodiments, the aqueous firefighting foam concentrate includes greater than about 60 wt.% water. In some embodiments, the aqueous firefighting foam composition may be produced using a source of water that has a total concentration of fluorine atoms on a weight percentage basis of no more than about 1 ppm F. In further embodiments, theaqueous firefighting foam composition may be produced using a source of water that has an amount of fluorine that is below detection limits.

[0033] The aqueous firefighting foam compositions of the present disclosure are substantially free of fluorine. In some embodiments, the composition has a total concentration of fluorine atoms of less than 0.01 wt.%. In some embodiments, the composition has a total concentration of fluorine atoms of less than 0.005 wt.%. In some embodiments, the composition has a total concentration of fluorine atoms on a weight percentage basis of no more than about 70 parts per trillion (ppt) F. The aqueous firefighting foam compositions of the present disclosure may include substantially less than 70 ppt F. In some embodiments, the total concentration of fluorine in the aqueous firefighting foam composition is below detection limits.

[0034] In some embodiments, the aqueous firefighting foam concentrate further includes one or more corrosion inhibitors. Illustrative and non-limiting corrosion inhibitors includes ortho- phenylphenol, tolyltriazole, and phosphate ester acids. In some embodiments, the corrosion inhibitor is tolyltriazole.

[0035] In some embodiments, the aqueous firefighting foam concentration further includes a reducing agent. When present, the reducing agent may be present in the foam concentration from about 0.01 wt% to about 5 wt%. This may include from about 0.01 wt% to about 3 wt%, from about 0.05 wt% to about 5 wt%, from about 1 wt% to about 5 wt%, or from about 1 wt% to about 3 wt%. The reducing agent may be selected such that it is more readily oxidized compared to other components of the foam. For example, the reducing agent may be oxidized more readily than the sugar component. Examples of reducing agents include, but are not limited to, sodium sulfite, sodium bisulfite, sodium metabisulfite, or a mixture of any two or more thereof.

[0036] In some embodiments, the aqueous firefighting foam concentrate may further include a preservative, such as one or more antimicrobial compounds and / or biocidal compounds. These components are included to prevent the biological decomposition of natural product based polymers that are incorporated as polymeric film formers (e.g., apolysaccharide gum). Examples include Kathon CG / ICP (Rohm & Haas Company), Givgard G-4 40 (Givaudan, Inc.), Dowicil 75, and Dowacide A (Dow Chemical Company).

[0037] Table 1 below provides an example of a formulation of the present firefighting foam compositions designed to be combined with a diluent, aerated, and administered to fight a fire as a firefighting foam.Table 1Method of Producing a Firefighting Foam

[0038] The firefighting foam concentrates described herein may be mixed with a diluent to form firefighting foam precursor solution, i.e., a use strength composition. The firefighting foam precursor solution may be aerated (e.g., using a nozzle) to produce a firefighting foam including the firefighting foam concentrate and the diluent. Illustrative diluents may include water, such as fresh water, brackish water, sea water, and combinations thereof. In some embodiments, the firefighting foam compositions described above may be 1 vol.%, 3 vol.%, or 6 vol.% concentrate solutions, meaning that the firefighting foam compositions are mixed with 99 vol.%, 97 vol. %, or 94 vol.% diluent, respectively, to form the firefighting foam precursor solution.

[0039] In some instances, it has been found that the order of addition of ingredients with appropriate agitation may impact the actual firefighting performance as seen in the UL and EN fire tests. It may be suitable to begin by mixing the sugar component and metal saltcomponent with a substantial amount of water until dissolved. The surfactants are then blended into the sugar and salt solution. Subsequently, a solution or slurry of the xanthan gum in the water-miscible solvents is prepared and then blended into the aqueous phase of the foam concentrate. It was found that first preparing a slurry of the xanthan gum in an organic solvent may facilitate later dissolution and / or dispersal of the xanthan gum in the water / surf actant / salt solution. This allows for the gums to properly hydrate without encapsulating (clumping) upon addition to the surfactant(s), other optional compounds, sugar, salt, and water.

[0040] Firefighting foams that were prepared not following this order of component addition may result in xanthan gum that is encapsulated, but not fully hydrated, which may result in the production of foams that are not satisfactory for fire testing. Thus, in some embodiments, the preparation of the xanthan gum slurry is important to the process of making the fire-fighting foam concentrate before adding the xanthan gum to the other components of the foam concentrate.Method of Fighting a Fire

[0041] The firefighting foam compositions described herein may be used to fight a fire and / or to suppress flammable vapors by mixing the firefighting foam compositions with a diluent, aerating the resulting firefighting foam precursor solution to form a firefighting foam, and administering the firefighting foam to a fire or applying the firefighting foam to the surface of a volatile flammable liquid (e.g., gasoline or other flammable hydrocarbon or a flammable polar solvent). In particular, the aqueous fire-fighting foam composition may be used to extinguish isopropyl alcohol (IP A) fires.

[0042] The xanthan gum crosslinked by a divalent metal salt allows the fire-fighting composition to be effective on IPA fires. Without wishing to limit the present disclosure by any theory or mechanism, the xanthan gum, strengthened by crosslinking with a divalent metal salt forms a blanket over the fuel and allows the foam to extinguish the fire rather than have the foam be degraded by the fuel. The xanthan blanket preserves the foam to also improve bum back performance.EXAMPLES

[0043] The following examples more specifically illustrate formulations for preparing aqueous firefighting compositions according to various embodiments described above. These examples should in no way be construed as limiting the scope of the present technology.Example 1. Exemplary Aqueous Fire-fighting Foam Concentrate Compositions

[0044] Tables 2 - 4 below show examples of formulations of the present aqueous firefighting foam composition. The amounts shown in these tables represent the weight percentage of the particular component based on the total weight of the composition. The formulations include a) xanthan gum crosslinked by a metal salt; b) a non-ionic surfactant; and c) water. The formulations may further include: d) an anionic surfactant; e) an amphoteric surfactant; f) a sugar component; and / or g) an organic solvent.Table 2Table 3Table 4Example 2, Effects of Metal Salts on Isopropyl Alcohol Performance

[0045] Tables 5 and 6 below show the effects of different metal salts on the performance of the fire-fighting compositions using a static lab-scale stability on isopropyl alcohol test and compared to a control having no metal salt. Table 5 demonstrates the differences between fire-fighting compositions having metal salts including divalent ions (DV1, DV2, DV4, Acl, Ac3, and Ac4) and monovalent ions (C12-C14). Divalent ions (excluding Mg2+) improve deacylated xanthan (Kelzan APAS) foam performance on isopropyl alcohol. Additionally, the larger the divalent ion, the better the IPA performance ofthe deacylated xanthan (Kelzan APAS) crosslinked by the divalent ion: strontium improved performance more than calcium. Table 6 demonstrates the performance of fire-fighting compositions including non-ionic surfactants and deacylated xanthan gum. Barium acetate improved the IPA foam stability the most, followed by calcium acetate, then strontium acetate, then magnesium acetate (which showed minimal improvement over the control).Table 5Table 6Example 3, Effects of Polysaccharides on Isopropyl Alcohol Performance

[0046] Tables 7-8 below show the effects of different polysaccharides on the performance of the fire-fighting compositions using the isopropyl alcohol static lab-scale stability test and compared to a control having no metal salt. Table 7 demonstrates the performance differences between different types of xanthan gum, and Table 8 demonstrates the performance differences of compositions having polysaccharides that are not xanthan gum. The presence of calcium chloride significantly improved the IPA performance of several deacylated xanthan gums (Kelzan APAS, Kelzan T+, Kelzan AP). The presence of calcium chloride slightly improved the IPA performance of Rhamsan gum. The presence of calcium chloride had no effect of the IPA performance of Kelzan BT (xanthan gum with no deacetylation), Rheozan, diutan, and welan gums.Table 7Table 8

[0047] While certain embodiments have been illustrated and described, it should be understood that changes and modifications may be made therein in accordance with ordinary skill in the art without departing from the technology in its broader aspects as defined in the following claims.

[0048] The embodiments, illustratively described herein may suitably be practiced in the absence of any element or elements, limitation or limitations, not specifically disclosed herein. Thus, for example, the terms “comprising,” “including,” “containing,” etc. shall be read expansively and without limitation. Additionally, the terms and expressions employed herein have been used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the claimed technology. Additionally, the phrase “consisting essentially of’ will be understood to include those elements specifically recited and those additionalelements that do not materially affect the basic and novel characteristics of the claimed technology. The phrase “consisting of’ excludes any element not specified.

[0049] The present disclosure is not to be limited in terms of the particular embodiments described in this application. Many modifications and variations may be made without departing from its spirit and scope, as will be apparent to those skilled in the art. Functionally equivalent methods and compositions within the scope of the disclosure, in addition to those enumerated herein, will be apparent to those skilled in the art from the foregoing descriptions. Such modifications and variations are intended to fall within the scope of the appended claims. The present disclosure is to be limited only by the terms of the appended claims, along with the full scope of equivalents to which such claims are entitled. It is to be understood that this disclosure is not limited to particular methods, reagents, compounds, compositions, or biological systems, which may of course vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting.

[0050] In addition, where features or aspects of the disclosure are described in terms of Markush groups, those skilled in the art will recognize that the disclosure is also thereby described in terms of any individual member or subgroup of members of the Markush group.

[0051] As will be understood by one skilled in the art, for any and all purposes, particularly in terms of providing a written description, all ranges disclosed herein also encompass any and all possible subranges and combinations of subranges thereof. Any listed range may be easily recognized as sufficiently describing and enabling the same range being broken down into at least equal halves, thirds, quarters, fifths, tenths, etc. As a non-limiting example, each range discussed herein may be readily broken down into a lower third, middle third and upper third, etc. As will also be understood by one skilled in the art all language such as “up to,” “at least,” “greater than,” “less than,” and the like, include the number recited and refer to ranges which may be subsequently broken down into subranges as discussed above. Finally, as will be understood by one skilled in the art, a range includes each individual member.

[0052] All publications, patent applications, issued patents, and other documents referred to in this specification are herein incorporated by reference as if each individual publication, patent application, issued patent, or other document was specifically and individually indicated to be incorporated by reference in its entirety. Definitions that are contained in text incorporated by reference are excluded to the extent that they contradict definitions in this disclosure.

[0053] Other embodiments are set forth in the following claims.

Claims

WHAT IS CLAIMED IS:

1. An aqueous fire-fighting foam concentrate comprising: a xanthan gum crosslinked by a metal salt; a surfactant component; and water.

2. The aqueous fire-fighting concentrate of claim 1, wherein the xanthan gum is deacylated or partially deacylated.

3. The aqueous fire-fighting concentrate of claim 1 or claim 2, wherein the metal salt comprises a divalent ion.

4. The aqueous fire-fighting concentrate of claim 3, wherein the divalent ion comprises Ca2+,Ba2+, Sr2^ Zn2+, or a mixture of any two or more thereof.

5. The aqueous fire-fighting concentrate of any one of claims 1-4, wherein the metal salt comprises calcium chloride, calcium acetate, strontium chloride, strontium acetate, barium chloride, barium acetate, zinc chloride, or a mixture of any two or more thereof.

6. The aqueous fire-fighting concentrate of any one of claims 1-5, wherein the surfactant component comprises a non-ionic surfactant, an anionic surfactant, an amphoteric surfactant, or a mixture of two or more thereof.

7. The aqueous fire-fighting concentrate of claim 6, wherein the non-ionic surfactant comprises an alkyl polyglycoside, an aliphatic alcohol-based nonionic surfactant, or a mixture of any two or more thereof.

8. The aqueous fire-fighting concentrate of claim 6 or 7, wherein the non-ionic surfactant comprises an alkyl polyglucoside, an aliphatic alcohol, an aliphatic alcohol ethoxylate, or a mixture of any two or more thereof.

9. The aqueous fire-fighting concentrate of any one of claims 6-8, wherein the anionic surfactant comprises an alkyl sulfate salt, an alkyl sulfonate salt, an alkyl ether sulfatesurfactant, an alkyl ether sulfonate surfactant, or a mixture of any two or more thereof.

10. The aqueous fire-fighting concentrate of any one of claims 6-9, wherein the amphoteric surfactant is selected from alkylamidoalkyl hydroxysultaine, an alkyl amidoalkyl betaine, an alkyl sulfobetaine surfactant, an alkyl betaine surfactant, or a mixture of any two or more thereof.

11. The aqueous fire-fighting concentrate of any one of claims 1-10 further comprising a sugar component, an organic solvent, or a mixture of any two or more thereof.

12. The aqueous fire-fighting concentrate of claim 11, wherein the sugar component comprises a monosaccharide sugar, a disaccharide sugar, a sugar alcohol, or a mixture of two or more thereof.

13. The aqueous fire-fighting concentrate of claim 11 or claim 12, wherein the sugar component comprises glucose, fructose, mannose, sucrose, maltose, lactose, lactulose, trehalose, cellobiose, chitobiose, xylose, sorbitol, mannitol, or a mixture of any two or more thereof.

14. The aqueous fire-fighting concentrate of any one of claims 11-13, wherein the organic solvent comprises an alkylene glycol, a glycerol, a water-soluble polyethylene glycol, a glycol ether, or a mixture of any two or more thereof.

15. An aqueous fire-fighting foam concentrate comprising: a xanthan gum crosslinked by a salt; a surfactant component comprising a non-ionic surfactant, an anionic surfactant, an amphoteric surfactant, or a mixture of two or more thereof; an organic solvent; a sugar component; and water.

16. An aqueous fire-fighting foam concentrate comprising: about 0.5 to 5 wt% of a xanthan gum crosslinked by a metal salt;about 0.1 to 15 wt% of the metal salt; about 1 to 30 wt% of a non-ionic surfactant; and at least about 30 wt% water.

17. The aqueous fire-fighting concentrate of claim 16 further comprising: about 2 to 20 wt% of an anionic surfactant; about 1 to 10 wt% of an amphoteric surfactant; about 0.5 to 20 wt% of an organic solvent; and about 5 to 25 wt% of a sugar component.

18. A method of forming a firefighting foam, the method comprising: mixing an aqueous fire-fighting concentrate with an aqueous diluent to form a foam precursor solution, the aqueous fire-fighting concentrate comprising: a xanthan gum crosslinked by a metal salt; a surfactant component; and water; and aerating the foam precursor solution to form the firefighting foam.

19. The method of claim 18, wherein the aqueous fire-fighting concentrate further comprises a sugar component and an organic solvent.

20. The method of claim 18 or 19, wherein the aqueous diluent comprises fresh water, brackish water, sea water, or a mixture of two or more thereof.

21. A method of extinguishing a fire, the method comprising: administering the firefighting foam of any one of claims 18-20 to the fire.

22. The method of claim 21, wherein the fire is an isopropyl alcohol fire.

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