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(11) EP 1 458 449 B1

(12) EUROPEAN PATENT SPECIFICATION

(45) Date of publication and mention (51) Int Cl.: of the grant of the patent: A62D 1/00 (2006.01) C05G 3/00 (2006.01) 09.01.2008 Bulletin 2008/02 C05B 13/00 (2006.01)

(21) Application number: 02721583.9 (86) International application number: PCT/US2002/009244 (22) Date of filing: 25.03.2002 (87) International publication number: WO 2003/057317 (17.07.2003 Gazette 2003/29)

(54) AMMONIUM POLYPHOSPHATE SOLUTIONS CONTAINING MULTI-FUNCTIONAL PHOSPHONATE CORROSION INHIBITORS AMMONIUMPOLYPHOSPHATLÖSUNGEN ENTHALTEND MULTIFUNKTIONELLE PHOSPHONAT- KORROSIONSINHIBITOREN SOLUTIONS DE POLYPHOSPHATE D’AMMONIUM CONTENANT DES INHIBITEURS DE CORROSION PHOSPHONATES MULTIFONCTIONNELS

(84) Designated Contracting States: (74) Representative: Albrecht, Thomas ES FR Kraus & Weisert Patent- und Rechtsanwälte (30) Priority: 26.12.2001 US 33601 Thomas-Wimmer-Ring 15 80539 München (DE) (43) Date of publication of application: 22.09.2004 Bulletin 2004/39 (56) References cited: EP-A- 0 911 067 GB-A- 2 234 501 (73) Proprietor: ICL Performance Products LP US-A- 3 960 735 US-A- 4 822 524 St. Louis MO 63141 (US) • DATABASE WPI Section Ch, Week 197949 (72) Inventors: Derwent Publications Ltd., London, GB; Class • VANDERSALL, Howard, L. E37, AN 1979-88266B XP002212823 & JP 54 Upland, CA 91784 (US) 138060 A (NIPPON KODOSHI KOGYO KK) , 26 • KEGELER, Gary, H. October 1979 (1979-10-26) Diamond Bar, CA 91765 (US)

Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention). EP 1 458 449 B1

Printed by Jouve, 75001 PARIS (FR) EP 1 458 449 B1

Description

FIELD OF THE INVENTION

5 [0001] The present invention relates to ammonium polyphosphate solutions. More specifically, the present invention relates to ammonium polyphosphate solutions containing iron additives and water-soluble phosphonates for reduced aluminum corrosion.

BACKGROUND OF THE INVENTION 10 [0002] Aerial application of fire-retardant compositions to combat the spread of wildland fires is common. The composition of fire retardant concentrates designed for managing and controlling wildland fires are of two general types: those that when mixed or diluted with water to end-use concentration, result in a gum- thickened solution, and those that do not contain a gum thickener and, consequently, result in water-like solutions, which are not rheologically modified 15 and exhibit inferior drop characteristics. The former may be supplied as dry powders or as suspensions or slurries, which are generally referred to as fluids. Those concentrates that result in water-like solutions when diluted with water may contain suspended components, as well, but are generally referred to as liquid concentrates. Fire retardant concentrates that are supplied as fluids or liquids are preferred by some because they can be simply and easily diluted to end-use strength with little mixing hardware and manpower. 20 [0003] Fertilizer grade ammonium polyphosphate liquids have been used as aerially applied fire-retardants. These liquids have certain advantages in comparison to other fire-suppressing compositions since they can be transported and stored prior to use in the liquid form rather than being mixed from dry ingredients. However, concentrated liquid fire retardants and solutions prepared therefrom are extremely corrosive to aluminum and brass and mildly corrosive to other materials of construction used in handling, storage and application equipment. As used herein, all metals include 25 alloys thereof. Accordingly, aluminum includes aluminum 2024T3, 6061 and 7074, steel includes 1010 and 4130 steel and brass includes yellow and naval brass. Since wildland fire retardants are most frequently transported to the fire and applied aerially, it is imperative that corrosive damage to the materials of construction of fixed- wing aircraft and helicopters be minimized. [0004] Accordingly, the United States Department of Agriculture ("USDA") Forest Service has established, in "Spec- 30 ification 5100-304b (January 2000) Superseding Specification 5100-00304a (February 1986)," entitled "Specification for Long Term Retardant, Wildland Fire, Aircraft or Ground Application" (hereinafter, "Forest Service Specifications") [0005] maximum allowable corrosion rates for 2024T3 aluminum, 4130 steel, yellow brass and Az-31-B magnesium, and weight loss procedures for determining such corrosion rates. For example, the corrosivity of forest fire retardants, in concentrate, to aluminum, steel and yellow brass must not exceed 0.13 mm (5.0 milli-inches ("mils")) pear year as 35 determined by the "Uniform Corrosion" test set forth in Section 4.3.5.1 of the aforementioned USDA, Forest Service Specifications. If the product is applied from fixed-tank equipped helicopters, the corrosivity of the fire retardants to magnesium must not exceed 0.13 mm (5.0 mils) per year. The Forest Service Specifications identify the maximum amount of corrosion acceptable when both the retardant concentrate and its diluted solutions are exposed to each metal indicated above at temperatures of 21°C (70° Fahrenheit ("F")) and 49°C (120°F) in both totally and partially immersed 40 configurations. The maximum allowable corrosivity of aerially applied fire retardant diluted solutions to aluminum is 0.05 mm (2.0 mils) per year ("mpy"), and the maximum corrosivity to brass and steel is 0.13 mmpy (5.0 mpy) when partially immersed, and 0.05 mmpy (20 mpy) when tested in the partially immersed condition. In the partially immersed configuration, one-half of the coupon is within the solution and one-half is exposed to the vapors in the air space over the solution. [0006] In an effort to address the corrosivity problems encountered with the use of fertilizer grade ammonium polyphos- 45 phates, sodium ferrocyanide was incorporated into the corrosive compositions. Sodium ferrocyanide has proved to be an effective corrosion inhibitor in fire retardant compositions containing ammonium polyphosphate fertilizer solutions. While sodium ferrocyanide is effective as a corrosion inhibitor, several disadvantages of its use make its incorporation into wildland fire retardant compositions undesirable. Specifically, the environmental and toxicological safety of ferro(i) cyanides is, at best, questionable. When exposed to acidic conditions and/or ultraviolet radiation from natural sunlight, 50 the ferro(i)cyanide radical readily degrades releasing free iron and cyanide and/or hydrogen cyanide, which are toxic to humans, animals and aquatic life. Further, free iron emanating either from decomposition of a portion of the ferro(i) cyanide radical, or introduced from other components or impurities within the composition, will subsequently react with remaining non-decomposed ferro(i)cyanide to form ferrous ferricyanide ("Turnbull’s Blue") or ferric ferrocyanide ("Prus- sian Blue"), which emit a persistent blue-black or indigo-blue coloration, staining all that they contact. Consequently, 55 neither ferricyanide nor ferrocyanide can be used in fire-retardants that are expected to fade and to become non- visible over time, for example, in fugitive retardant compositions. [0007] The magnitude of the above concerns is increased since wildland fire retardants are generally applied aerially in a less than completely controlled manner. Due to the presence of variables such as vegetative cover, smoke, or wind

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drift that affect the trajectory of the free-falling solution, aerially applied wildland fire retardant solutions may land on or near people, animals and in bodies of water, or on soil where it could enter the water supply. [0008] Accordingly, there is a need to provide safe and acceptable wildland fire retardants for the suppression or management of wildland fires that are not corrosive to the equipment associated with the transportation, handling and 5 application of the retardant, have favorable rheological and aerial application characteristics and are environmentally and toxicologically friendly, thereby avoiding the above disadvantages.

SUMMARY OF THE INVENTION

10 [0009] In accordance with the objects of the invention, novel compositions and methods are provided. In a first aspect of the invention, a corrosion-inhibited fire retardant composition comprises at least one fire retardant composition comprising at least one ammonium polyphosphate, at least one suspending agent, at least one phosphonate selected from a group consisting of aminotri(methylenephosphonic acid), 1-hydroxyethylidene- 1,1-diphosphonic acid, hexamethylenediaminetetra(methylenephosphonic acid), diethylenetriaminepenta(methylenephosphonic acid), salts thereof, and mix- 15 tures thereof, and a corrosion inhibiting system comprising at least one corrosion inhibiting compound selected from a group consisting of azoles, water-insoluble ferric pyrophosphate, water-soluble ferric pyrophosphate, ferrous oxalate, ferric citrate, ferrous sulfate, ferric ammonium citrate, water-insoluble ferric orthophosphate, water-soluble ferric orthophosphate, ferric ammonium oxalate, ferric ammonium sulfate, ferric bromide, ferric sodium oxalate, ferric stearate, ferric sulfate, ferrous acetate, ferrous ammonium sulfate, ferrous bromide, ferrous gluconate, ferrous iodide, ferric acetate, 20 ferric fluoroborate, ferric hydroxide, ferric oleate, ferrous fumarate, ferrous oxalate, ferrous oxide, ferric lactate, ferric resinate, and any combination thereof. The corrosion inhibiting system is present in an amount effective to substantially reduce the corrosiveness of the fire retardant composition over that which it would exhibit without the corrosion inhibiting system. [0010] In a second aspect ofthe invention, a method of preparing adiluted corrosion- inhibitedfire retardant composition, 25 adapted for application to wildland fires, is provided that comprises forming an intermediate concentrate composition comprising the above- described corrosion-inhibited fire retardant composition, and diluting the intermediate concentrate with water to form the diluted corrosion-inhibited fire retardant composition of the invention. [0011] In a third aspect of the invention, a method of suppressing wildland fires is provided that comprises applying to wildland vegetation a fire suppressing composition comprising the above-described diluted corrosion-inhibited fire 30 retardant composition. [0012] In a fourth aspect of the invention, a method of inhibiting corrosion is provided that comprises contacting a corrodible material with the above-described corrosion-inhibited composition. [0013] In a fifth aspect of the invention, a corrosion-inhibited agricultural plant nutrient is provided that comprises at least one agricultural plant nutrient, at least one suspending agent, at least one phosphonate selected from a group 35 consisting of aminotri(methylenephosphonic acid), 1-hydroxyethylidene-1,1-diphosphonic acid, hexamethylenediaminetetra(methylenephosphonic acid), diethylenetriaminepenta(methylenephosphonic acid), salts thereof, and mixtures thereof, and a corrosion inhibiting system comprising at least one corrosion inhibiting compound selected from a group of corrosion inhibiting compounds consisting of azoles, insoluble ferric pyrophosphate, soluble ferric pyrophosphate, ferrous oxalate, ferric citrate, ferrous sulfate, ferric ammonium citrate, insoluble ferric orthophosphate, soluble ferric 40 orthophosphate, ferric ammonium oxalate, ferric ammonium sulfate, ferric bromide, ferric sodium oxalate, ferric stearate, ferric sulfate, ferrous acetate, ferrous ammonium sulfate, ferrous bromide, ferrous gluconate, ferrous iodide, ferric acetate, ferric fluoroborate, ferric hydroxide, ferric oleate, ferrous fumarate, ferrous oxalate, ferrous oxide, ferric lactate, ferric resinate, and any combination thereof.

45 DESCRIPTION OF THE PREFERRED EMBODIMENT

[0014] In accordance with the present invention, it has been discovered that a fire-retardant composition can be prepared that has a reduced tendency to corrode various metals, including aluminum, that is superior to known fire retardants in rheological aerial application characteristics and is toxicologically and environmentally safe. The corrosion- 50 inhibited fire retardant compositions of the invention include at least one fire retardant composition comprising at least one ammonium polyphosphate, at least one novel phosphonate, or salt thereof, at least one suspending agent, and a corrosion inhibiting system comprised of at least one corrosion inhibiting compound selected from a group of corrosion inhibiting compounds consisting of azoles, water-insoluble ferric pyrophosphate, water-soluble ferric pyrophosphate, ferrous oxalate, ferric citrate, ferrous sulfate, ferric ammonium citrate, water-insoluble ferric orthophosphate, water- 55 soluble ferric orthophosphate, ferric ammonium oxalate, ferric ammonium sulfate, ferric bromide, ferric sodium oxalate, ferric stearate, ferric sulfate, ferrous acetate, ferrous ammonium sulfate, ferrous bromide, ferrous gluconate, ferrous iodide, ferric acetate, ferric fluoroborate, ferric hydroxide, insoluble ferric oleate, ferrous fumarate, ferrous oxide, ferric lactate, ferric resinate, and any combination thereof. Generally, the corrosion inhibiting system is present in an amount

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effective to substantially reduce the corrosiveness of the fire retardant composition over that which the fire retardant of the invention would exhibit in the absence of the corrosion inhibiting system. [0015] In accordance with the present invention, the corrosion-inhibited fire retardant composition of the invention includes a fire retardant comprising at least one ammonium polyphosphate. Ammonium polyphosphate is also referred 5 to as polyammonium phosphate and may include both ortho- and polyphosphate, other ammonium phosphates such as pyro- and metaphosphates, the alkali metal equivalents thereof, as well as a blend of phosphate polymers. [0016] The ammonium polyphosphate solutions that are used as agricultural fertilizer and wildland (vegetative) fire retardants are manufactured by neutralizing aqueous solutions of wet-process phosphoric acid, generally containing about 68% to about 74% phosphorus pentoxide, with anhydrous ammonia in such a manner that both high temperature 10 and pressure are experienced. When prepared in this manner, a portion of the impure orthophosphoric acid polymerizes or condenses, resulting in the formation of pyrophosphate, short chain polyphosphates and, in most instances, small amounts of cyclic or metaphosphates. That portion of the acid which does not polymerize, of course, remains as orthophosphoric acid. Ammoniation of this mixture of phosphate species occurs within the reactor, as well, resulting in an aqueous solution containing ammonium ortho, pyro, tripoly, tetrapoly and some higher chain and cyclic phosphate 15 species. These condensed phosphates generally exhibit increased water solubility as compared to orthophosphates and, consequently, more highly concentrated solutions can be prepared when such condensed phosphates are present. The relative concentrations of the various species depends primarily on the temperature and pressure achieved within the reactor. Commercial solutions generally contain from about 34% to about 37% phosphorus pentoxide. Phosphorus pentoxide concentrations above about 37% approach water solubility limits resulting in solutions that are not stable, 20 from which solids may precipitate during ambient temperature storage. Solutions of this type are generally referred to as either 10-34-0 or 11-37-0 liquid concentrates; the numerical designation refers to the percentage of their plant nutrient composition, i.e., ammoniacal nitrogen, phosphorus pentoxide and potassium oxide, respectively. [0017] It should be noted that the condensed phosphates that are present in liquid concentrate solutions are subject to hydrolyses which results in depolymerization. The rate of hydrolytic degradation increases with time, temperature and 25 the relative acidity of the solution. Therefore, ammonium polyphosphate concentrates and their solutions may vary in species composition as received and as time progresses during their subsequent storage. [0018] These liquid concentrates may additionally contain small amounts of diammonium sulfate and a host of metal and alkali-metal impurities. The quantity and quality of these impurities vary with the composition of the phosphate ore from which they are derived, the utilized process and the extent of purification that is conducted during manufacture of 30 the wet-process phosphoric acid. Since these solutions are manufactured primarily as nutrients, the quality control parameters of greatest interest are the percentages of their contained nutrients - nitrogen and phosphorus - and the clarity, stability and color of the solution rather than purity per se. [0019] The corrosion inhibiting system of the invention comprises at least one corrosion inhibiting compound selected from a group consisting of azoles, water-insoluble ferric pyrophosphate, water-soluble ferric pyrophosphate, ferrous 35 oxalate, ferric citrate, ferrous sulfate, ferric ammonium citrate, water-insoluble ferric orthophosphate, water- soluble ferric orthophosphate, ferric ammonium oxalate, ferric ammonium sulfate, ferric bromide, ferric sodium oxalate, ferric stearate, ferric sulfate, ferrous acetate, ferrous ammonium sulfate, ferrous bromide, ferrous gluconate, ferrous iodide, ferric acetate, ferric fluoroborate, ferric hydroxide, ferric oleate, ferrous fumarate, ferrous oxalate, ferrous oxide, ferric lactate, ferric resinate, and any combination thereof. In one preferred embodiment, the corrosion inhibiting system comprises at least 40 one water-soluble corrosion inhibiting compound and at least one water-insoluble corrosion inhibiting compound. The combination of such water- soluble and water- insoluble corrosion inhibiting iron containing compounds appears to provide the optimum combination of corrosion inhibition. [0020] An amount of the corrosion inhibiting system of the invention effective to reduce the corrosiveness of the fire retardant composition is included in the corrosion-inhibited fire retardant compositions of the invention. An effective 45 amount of the corrosion inhibiting system is that amount that substantially reduces the corrosivity of the fire retardant over that which it would exhibit in the absence of the corrosion inhibiting system. As is understood by those of ordinary skill in the art, what constitutes a substantial reduction in corrosivity is largely dependent on the specific fire retardant used in the fire retardant composition of the invention, as well as the specific composition of the corrosion inhibiting system and can be readily determined without undue experimentation. 50 [0021] In one embodiment, the corrosion inhibiting system of the invention is present in an amount effective in the corrosion-inhibited fire retardant composition, in concentrate, to impart to the corrosion-inhibited fire retardant concentrate at least one of a maximum corrosivity of aluminum to 0.13 mmpy (5.0 mpy), yellow brass to 0.13 mmpy (5.0 mpy) and steel to 0.13 mmpy (5.0 mpy) as determined by the Forest Service

55 Specifications.

[0022] In a specific embodiment, the corrosion inhibiting system of the invention comprises from 0.01% to 10.0% by weight of the total corrosion- inhibited fire retardant composition. In another specific embodiment, the corrosion inhibiting

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system of the invention comprises from 0.3% to 6.0% by weight of the total corrosion- inhibited fire retardant composition. In yet another specific embodiment, the corrosion inhibiting system of the invention comprises from 0.6% to 5.0% by weight of the total corrosion-inhibited fire retardant composition. [0023] It has been discovered that when low concentrations of novel water- soluble phosphonates are mixed with neat, 5 ammonium polyphosphate type fire retardants, both in concentrate and its diluted solution, corrosion rates are reduced significantly. Phosphonates, also referred to as phosphonic acids, are multi-functional metal ion control agents. By definition, they contain at least one functional group, PO3H2, bonded to a carbon atom. Phosphonates are generally strongly negatively charged, stable in aqueous systems, high temperature, pressure and Ph extremes, highly soluble in aqueous systems, and compatible with other compounds. Although phosphonates do not readily biodegrade in con- 10 tinuous activated sludge tests, they disappear rapidly in the environment by a combination of photolytic and biological degradation steps. Further, phosphonates appear to possess no acute toxicological properties, which would require special handling that would differ from any strong industrial acid. The novel water- soluble phosphonates suitable for use in the present invention include aminotri(methylenephosphonic acid), 1-hydroxyethylidene-1,1-diphosphonic acid, hexamethylenediaminetetra(methylenephosphonic acid), diethylenetriaminepenta(methylenephosphonic acid), and salts 15 thereof. As one skilled in the art should readily recognize, mixtures of these novel phosphonates, and their salts, are suitable for use in the present invention. The phosphonates of the present invention are readily commercially available from Solutia Inc. in St. Louis, MO, and may also be manufactured by one skilled in the art using known methods. [0024] In a specific embodiment of the invention, aminotri (methylenephosphonic acid), also known as ATMP or AMP, is employed in the present invention. ATMP is represented by the following structure: 20

25

30

The pentasodium salt of ATMP, also referred to as Na5ATMP, is also suitable for use in the present invention. 35 [0025] In yet another embodiment, 1-hydroxyethyldiene- 1,1-diphosphonic acid, also referred to as HEDP, is employed. The tetrasodium salt of HEDP, also referred to as Na4HEDP, is also suitable for use in the present invention. HEDP is represented by the following structure:

40

45

[0026] In a further embodiment of the invention, hexamethylenediaminetetra(methylenephosphonic acid), also referred to as HDTMP, is employed. The hexapotassium salt of HDTMP, also referred to as K6HDTMP, is also suitable for use 50 in the present invention. HDTMP is represented by the following chemical structure:

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5

10

[0027] In still a further embodiment of the invention, diethylenetriaminepenta (methylenephosphonic acid), also referred to as DTPMP, is employed. The hexasodium salt thereof, also known as Na6DTPMP is also suitable for use in the present invention. DTPMP is represented by the following chemical structure: 15

20

25

[0028] The concentrated fire retardant compositions of the invention generally comprise less than 10% by weight of 30 at least one of the above-described phosphonates, based on the total weight of the ammonium polyphosphate composition. This is equivalent to 2.3% by weight active content in the concentrated fire retardant compositions. In one embodiment, the concentrated fire retardant compositions of the invention comprise from 1.0% to 10% (0.23% - 2.3% active), by weight, of at least one of the above-described phosphonates. In a specific embodiment, the concentrated compositions of the invention comprised 4.35% (1.0% active content), by weight, of at least one of the above- described 35 phosphonates. [0029] The fire retardant compositions of the invention also contain at least one suspending agent. Suspending agents reduce the rate of separation and settling during long term storage. Thus, as one skilled in the art would appreciate, the amount of suspending agent utilized depends upon its relative effectiveness per unit applied, the desired length of storage, and the additional additives incorporated into the compositions of the invention. Suspending agents useful in 40 the compositions of the invention include colloidal clays, for example, Attapulgus, Fuller’s earth, Sepiolite, Montmorillonite, Kaolin clays, and mixtures thereof. As used herein, Attapulgus clay includes, but is not limited to attapulgite and poly- gorskite. As used herein, Kaolin clay includes, but is not limited to Kaolinite, [Al 2Si2O7-2(H2O)] and [Al 2O3-2SiO2-2(H2O)]. [0030] As will be apparent to those skilled in the art, the fire retardant compositions of the invention may contain or be mixed with other functional components or additives such as coloring agents, surfactants, stabilizers, opacifying 45 agents, rheological modifying agents, any combination thereof. Suitable coloring agents include, but are not limited to both fugitive and non-fugitive coloring agents and pigments, extenders, opacifying pigments, and other highly colored coloring agents. Rheological modifying agents suitable for use include, but are not limited to guar gum, derivatized guar gum and xanthan gum. [0031] For example, and in one embodiment of the invention, the corrosion- inhibited fire retardant composition of the 50 invention includes at least one highly colored pigment. The highly colored pigment is incorporated to assist in the visual identification of treated and untreated vegetation. Suitable highly colored pigments include iron oxide, which produces many colors like brown and red, titanium dioxide pigments, which produce a white color, or an ultraviolet sensitive dye dispersed in biodegradable plastic. However, for certain uses, like along roadsides or in parks, it may be desirable to exclude colorant from the mixture. Accordingly, as one skilled in the art would appreciate, the amount of colorant or 55 pigment incorporated into the compositions of the invention depends on the degree of dilution and visibility contemplated by the user. Visibility is usually obtained with red iron oxide when it is present in the diluted solution in the range of 0.15% to 0.4% by weight, depending on the colorant characteristics and on the vegetative and topographical characteristics of that on which it will be applied. The amount incorporated in the concentrate will, of course, vary with the dilution rate

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required to provide adequate fire retarding effectiveness. [0032] In another embodiment, the present invention includes at least one of red iron oxide or brown iron oxide, or a combination thereof. In yet another embodiment, the present invention includes a fugitive coloring agent, whose color fades upon exposure to the elements. In a further embodiment, the present invention includes opacifying pigments, 5 which are generally not highly colored, but have the ability to cover and hide that on which they are deposited so that the highly colored pigment becomes more visible. [0033] Surfactants may also be added to increase visibility, through the generation of a foam; and to improve penetration of the retardant solution into porous fuels. Accordingly, as one skilled in the art would appreciate, the amount and type of surfactant incorporated into the compositions of the invention depends on the degree of the dilution and visibility 10 contemplated by the user. [0034] It has been discovered that azoles are effective corrosion inhibitors for brass. In one embodiment of the invention, the compositions of the invention comprise at least one azole. As used herein, an azole is any of a group of chemical compounds with a five-membered ring containing one or more nitrogen atoms. Azoles suitable for use in the corrosion- inhibited fire retardants of the invention include, but are not limited to tolytriazole, benzotriazole, mercaptobenzothiazole, 15 dimercaptothiadiazole, 1,2 benzisothiazoline-3-1,2-benzimidazolone, 4,5,6,7-tetrahydrobenzotriazole, tolylimidazole, 2-(5-ethyl-2-pyridyl) benzimidazole, phthalimide, any alkali metal salts thereof and combinations thereof. The amount of azole or other corrosion inhibitor is dependent upon the corrodible metal for which corrosion resistance is desired, the level of resistance desired, and the specific concentration of the fire retardant composition employed, including corrosion inhibiting compounds contained therein. 20 [0035] The diluted corrosion-inhibited fire retardant compositions of the invention, adapted for application to wildland fires, are prepared in accordance with the present invention by forming an intermediate concentrate composition comprising the above-described corrosion-inhibited fire retardant compositions of the invention, and diluting the intermediate concentrate with water to form the diluted compositions of the invention, adapted for application to wildland fires. The intermediate concentrate is formed by methods well known in the art, for example, by admixing the above-described 25 elements comprising the fire retardant compositions of the invention using manual or mechanical mixing techniques. [0036] To suppress wildland fires, the corrosion-inhibited fire retardant compositions of the invention are diluted with water and applied on threatened vegetation, ahead of approaching wildland fire. Ammonia from both the ammonium phosphate and the ammonium sulfate are liberated at temperatures below the ignition temperature of the fuel. The phosphoric and sulfuric acids are both initially effective fire retarding acids. The phosphoric acid will remain present and 30 effective with the vegetative fuel until temperatures exceed 600°C. However, the boiling point of sulfuric acid is much lower and the amount present will decrease as fuel temperature increases. Thus, at least a portion of the sulfuric acid is still present at the ignition temperature of the fuel. The resultant mineral acids subsequently react with the cellulosic components of vegetative fuels on which they are applied. Their thermal decomposition is thereby altered in such a manner that they will no longer serve as fuel. These reactions are described in U.S. Pat. No. 4,839,065 to Vandersall. 35 [0037] Prior to use, and in one embodiment of the invention, the compositions of the invention are blended with water to form dilute solutions containing the amount of phosphorus pentoxide required to achieve the maximum amount of vegetation coverage at an application rate sufficient to reduce the flammability of the vegetative fuels to the desired level. The water used in the composition of the invention may be tap water or water from other convenient water sources. [0038] In a specific embodiment, the compositions of the invention are blended with water to form dilute solutions 40 containing the amount of phosphorus pentoxide required to meet USDA, Forest Service Specification fire-retardant effectiveness requirements. This concentration, which is determined via combustion- retarding effectiveness testing described in USDA, Forest Service Specification 5100-304b, "4.5.2. Combustion Retarding Effectiveness Test," will generally depend on the percentage of phosphorus pentoxide present in the concentrated composition and the extent of its availability for retarding reactions. The minimum corrosivity rate specified in the Forest Service Specifications is generally 45 obtained when the fire retardant concentrate of the invention is diluted with about 1 to about 8 volumes of water. [0039] In yet another specific embodiment, the diluted corrosion-inhibited fire retardant composition has a maximum corrosivity of aluminum to 0.05 mm (2.0 mils) per year, of brass to 0.05 mm (2.0 mils) per year, and of steel to 0.05 mm (2.0 mils) per year when tested in the above-described partially immersed condition, described by the Forest Service Specifications. 50 [0040] In one embodiment, the above described fire retardant compositions are used as agricultural plant nutrients. The corrosion inhibiting system is present in an amount effective to substantially reduce corrosiveness of the agricultural plant nutrient over that which it would exhibit in the absence of the corrosion inhibiting system. As one skilled in the art can appreciate, the effective amount varies depending on the specific plant nutrient formulated. However, one skilled in the art can readily determine the amount without undue experimentation. 55 [0041] A method of inhibiting corrosion using the fire retardant composition of the invention is also provided. According to the method of the invention, an effective amount of the corrosion inhibiting system is incorporated into the concentrated fire retardant composition of the invention. A corrodible material is then brought into contact with the corrosion- inhibited fire retardant concentrate and/or its diluted solution. An effective amount of the corrosion inhibiting system of the invention

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ispresent in the corrosion inhibited fire retardant composition to substantially reduce the corrosiveness of the fire retardant, in concentrate and dilute solution, to the corrodible material, over that which it would exhibit without the corrosion inhibiti ng system is present in the corrosion inhibited fire retardant composition. Any corrodible material may be used according to the method of inhibiting corrosion of the invention. In one embodiment, the corrodible material is one selected from 5 a group consisting of steel, brass, aluminum and any alloy thereof. Prior to use, and in one embodiment of the invention, the fire retardant compositions of the invention are blended with water prior to or during contact with the corrodible material The water used may be tap water or water from other convenient water sources. [0042] In one embodiment, the corrosion inhibiting system includes at least one additive selected from a group of additives including coloring agents, surfactants, opacifying pigments, stabilizers, rheological modifying agents, and any 10 combination thereof. Suitable coloring agents include, but are not limited to both fugitive and non-fugitive coloring agents and pigments, extenders, opacifying pigments, and other highly colored coloring agents. Rheological modifying agents suitable for use include, but are not limited to guar gum, derivatized guar gum and xanthan gum. [0043] The following examples illustrate specific embodiments of the invention without limitirig the scope of the invention in any way. Examples 1-7 are not embodiments of the invention. In each example, samples of ammonium polyphosphate 15 fire retardant concentrates were mechanically admixed with iron containing compounds and the phosphonates described, and in some cases, with an azole. Any mechanical mixing technique that is well known in the art may be used in the present invention. The diluted fire retardant solutions are diluted with water, as indicated. The "Requirements" row illustrates the level of aluminum 2024-T3 corrosion allowed by the Forest Service Specifications, i.e., the maximum allowable corrosivity for product acceptance for use in wildland fire retardant compositions. The resulting samples were 20 tested for corrosivity in accordance with USDA, Forest Service Specifications 5100-304b.

EXAMPLE 1-THE ALUMINUM CORROSIVITY OF NEAT AMMONIUM POLYPHOSPHATE SOLUTION

[0044] Table 1 illustrates the corrosion characteristics of neat, unadulterated fertilizer grade 10-34-0 and 11-37-0 25 ammonium polyphosphate liquid concentrates obtained from three different sources. All of the samples are either 10-34-0 or 11-37-0, as received, with no additions. The corrosivity of the samples were expressed in mm per year ("mmpy") (milli-inches per year ("mpy")) of metal loss on exposed metal surface based on the conventional Forest Service Spec- ifications for determining corrosivity. Both the concentrated retardant and its diluted solutions were tested at each temperature and condition indicated. 30 [0045] The diluted solutions were prepared by admixing four to five volumes of water with one volume of the concentrated solution. Thus, the concentration of concentrate in diluted solutions in each case was in the range of between about 15% to about 20% by volume. [0046] In accordance with the Forest Service Specifications for corrosion testing of fire retardants, a 2.54 cm (one- hich) wide, 10.16 cm (four- inch) long 032 cm (one-eigth inch) thick coupon of the aluminum was obtained from a standard 35 source. The coupon is cleaned, dried and weighed according to standard Forest Service Specifications and suspended in a 0.941 (one-quart) straight sided jar filled either 50% (partially) or 100% (totally) using a piece of nylon string. When suspended in a partially full jar, the coupon was 50% (5.08cm (two-inches)) immersed in the test solution with the other 50% extending up from the solution into the air space above it. When the jar was full with approximately 800 ml of the solution, the metal coupon was totally immersed in the solution. The jars were then closed with a screw cap and two or 40 three identical corrosion jars (cells) of each partially and totally immersed coupons were stored at 21°C (70°F) and 49°C (120°F) for ninety days. At the end of the ninety- day storage period, the jars were opened and the coupons were removed and cleaned according to the Forest Service Specifications. After each coupon dried it was re-weighed and its weight loss was determined by comparing its initial and final weights. The calculated weight loss and density of the metal coupon were used to extrapolate to mm (mils (0.001 inches)) of aluminum that would be lost during a one-year period at the test 45 condition, assuming that the weight loss was experienced uniformly across the coupon surface. The corrosion rates of both the partially and totally immersed coupons were calculated using the total surface area of the coupon. The samples at each condition were then averaged and reported as the corrosion rate. The results are shown in Table 1.

50

55

8 EP 1 458 449 B1

5 2.0) ≤ (7.8) 0.05 ( 0.05 ≤ partial

10 2.0) ≤ (11.4) 0.20 0.05 ( 0.90 (35.8) 0.90 (12.4) 0.31 0.88 (35.1) 0.88 0.19 (7.4) 0.19 0.15 (5.8) 0.15 0.16(6.4) 0.27 (10.8) 0.53 (21.1) 0.28 (11.0) 0.57 (22.8) 0.84 (33.7) 0.33 (13.3) 0.73 (29.2) ≤

15 2.0) ≤ 0.05 ( 0.05 ≤ partial total Diluted Solution Diluted

20 2.0) ≤ (15.2) 0.21 (8.4) 2.55 (10.1) 0.14(5.6) 0.05 ( 0.05 0.28(11.0) 0.32 (12.7) 0.32 (13.8) 0.35 0.32 (12.7) 0.32 ≤ 25 5.0) ≤ (77.8) 0.21 (8.4) 0.16 (6.5) 0.62 (24.9) 0.14(5.7) 0.13 ( 0.13 ≤ 30 partial total Table 1 Table 5.0) ≤

35 0.13 ( 2.74 (109.4) 2.74 3.89 (155.6) 3.89 (115.8) 2.90 4.42 (176.9) 4.42 4.21 (168.5) 4.21 3.65 (146.0) 3.65 3.25 (130.0) 4.25 (170.0) 3.16 (126.2) 3.74 (149.4) 3.24 (129.4) 3.41 (136.3) 3.79 (151.5) ≤ 5.0) ≤

40 0.13 ( 0.13 ≤ partial total 5.0) ≤

45 °C (70°F) (70°F) 21°C (120°F) 49°C (120°F) 49°C (70°F) 21°C (70°F) 21°C 49°C (120°F) (120°F) 49°C 0.13 ( 0.26 (10.2) 0.26 (10.9) 0.27 (5.3) 0.13 (5.5) 0.14 (165.0) 4.13 (161.4) 4.04 (88.b) 2.22 (85.3) 2.13 (12.3) 0.31 (12.0) 0.30 (6.4) 0.16 (7.0) 0.18 (21.8) 0.55 (39.0) 0.98 (13.3) 0.33 (14.8) 0.37 0.11 (4.3) 0.11 (9.5) 0.24 (9.9) 0.25 0.32 (12.7) 0.32 (13.1) 0.33 (6.0) 0.15 (7.1) 0.18 (201.0) 5.03 (159.0) 3.98 (96.5) 2.41 (86.7) 2.17 (12.8) 0.32 (11.2) 0.28 (7.5) 0.19 (6.5) 0.16 (35.8) 0.90 (42.7) 1.07 (19.3) 0.48 (21.8) 0.55 0.20(8.1) 0.10(4.1)(140.7) 3.52 (67.4) 1.69 (5.8) 0.15 0.16(6.3) 0.29 0.30 (12.0) 0.30 (6.3) 0.16 (144.8) 3.62 (94.5) 2.36 (17.7) 0.44 (10.4) 0.26 (10.5) 0.26 (7.0) 0.18 0.38 (15.2) 0.38 0.31 (12.4) 0.31 (6.6) 0.17 (106.6) 2.67 1.96(78.5) 0.38 0.22 (8.7) 0.22 (4.3) 0.11 (134.3) 3.36 1.95 ≤ Aluminum Corrosivity when tested in the indicated configuration (mmpy (mpy)) (mmpy configuration indicated the in tested when Corrosivity Aluminum Concentrate Neat total

50

55 Sample 9 Sample Sample 10 Sample 8 Sample Sample 6 7 Sample Sample 11 Sample 13 Sample 5 Sample 12 Sample 14 Sample Sample 18 20 Sample Sample 15 Sample 16 Sample Sample 17 Sample 19 Sample Sample 21 Sample Sample 4 Sample Sample 3 Sample Sample 2 Sample Sample 1 Sample Ammonium Polyphosphate Ammonium 21 Samples Requirements

9 EP 1 458 449 B1

5 (12.6)

10 (22.0) 0.32

15

20

25 (83.3) (12.2) 0.31 (7.4) 0.19 0.55

30 (continued)

35

40

45 (10.6)(5.6) 0.14 (147.7) 3.69 2.08 °C (70°F) (70°F) 21°C (120°F) 49°C (120°F) 49°C (70°F) 21°C (70°F) 21°C 49°C (120°F) (120°F) 49°C 0.11-0.38 0.10-0.18 2.67-5.03 1.69-2.36 0.15-0.44 0.16-0.26 0.15-1.07 0.14-0.55 (4.3-15.2) (4.1-7.1) 106.6-201.0 (67.4-94.5) (5.8-17.7) (6.3-10.4) (5.8-42.9) (5.6-21.8)+- 0.27 0.27 (10.9) 0.27 (5.5) 0.14 (172.6) 4.32 (74.8) 1.87 (13.1) 0.32 (7.2) 0.18 (42.9) 1.07 (18.3) 0.46

50

55 Range (Lo-Hi) Range Ammonium Polyphosphate Ammonium 21 Samples22 Sample Average total partial total partial total partial total partial

10 EP 1 458 449 B1

[0047] The corrosivity of the ammonium polyphosphate solutions to aluminum 2024T-3 was relatively low when the temperature was maintained at about 21°C (70°F) However, none of the samples of the neat ammonium polyphosphate solutions met the Forest Service Specifications for corrosivity of fire retardants. In addition, the results show that increasi ng the solution temperature to 49°C (120°F) dramatically increases the corrosion of the aluminum coupon by the neat 5 ammonium polyphosphate samples, i.e., in excess of an order of magnitude.

EXAMPLE 2-THE ALUMINUM CORROSIVITY OF AMMONIUM POLYPHOSPHATE SOLUTION CONTAINING IRON OXIDE & ATTAPULGUS CLAY

10 [0048] The corrosion characteristics of neat fertilizer grade ammonium polyphosphate solutions containing additional amounts (<3%) of a mixture of an iron oxide colorant and Attapulgus clay is illustrated in Table 2. Each sample was prepared by admixing neat concentrated ammonium polyphosphate obtained from several sources with Attapulgus clay, and either 1.2% red iron oxide or 1.2% brown iron oxide, as indicated. In addition, 0.3% tolytriazole was also admixed into samples 11, 15, 16, 18 and 19 and 0.5% tolytriazole was admixed into sample 20. Aliquots from these concentrate 15 samples were then diluted by admixing 1.0 volume of concentrate with 4.25 volumes of tap water. The concentrates and their solutions were then tested for corrosivity and diluted in accordance with Forest Service Specifications. The results are shown in Table 2.

20

25

30

35

40

45

50

55

11 EP 1 458 449 B1 2.0) ≤

5 0.05 ( ≤ total 2.0) ≤ 10 0.05 ( 0.05 ≤ 0.09 (3.7) 0.09 (2.3) 0.06 (10.1) 0.25 (4.5) 0.11 (3.1) 0.08 (3.8) 0.10 (0.8) 0.02 (5.3) 0.13 (4.2) 0.11 0.29 (11.7) 0.29 (7.1) 0.18 (3.9) 0.10 (3.8) 0.10 0.05 (2.0) 0.05 2.0) ≤ 15 0.05 ( 0.05 ≤ total total 2.0) 20 ≤ 0.05 ( 0.05 ≤ total Diluted Solution Diluted 0.07 (2.7) 0.07

25 5.0) ≤ 0.13 ( 0.13 total ≤

30 5.0) Table 2 Table ≤ (1.4) (4.4) 0.11 0.13 ( ≤ 0.04 (0.7) 0.02 (1.4) 0.04 (6.4) 0.16 (2.3) 0.06 (3.0) 0.08 (15.3) 0.38 (32.1) 0.80 (8.3) 0.21 (26.3) 0.66 (19.7) 0.49 (4.3) 0.11 (6.7) 0.17 (2.3) 0.06 0.20 (8.0) 0.20

35 5.0) ≤ (5.6)(147.7) 3.69 (83.3) 2.08 (12.2) 0.31 (7.4) 0.19 (22.0) 0.55 (12.6) 0.32 (1.9) (6.7) 0.17 (3.8)(9.0) 0.23 (1.7) 0.04 (4.3) 0.11 (1.6) 0.04 (3.9) 0.10 (2.8) 0.07 (2.5) 0.06 (4.3) 0.11 (3.3) 0.08 (3.5) 0.09 (3.6) 0.09 0.13 ( 0.13 ≤

40 5.0) ≤ °C (70°F) (70°F) 21°C 49°C (120°F) (120°F) 49°C (70°F) 21°C (70°F) 21°C (120°F) 49°C 49°C (120°F) 0.13 ( 0.13 0.27 (10.6) 0.14 Neat Concentrate Neat 21 total total≤ total 0.12 (4.6)0.12 (3.5) 0.09 (3.6) 0.09 0.05 (7.3) 0.18 (3.5) 0.09 0.10 (5.0) 0.13 (6.7) 0.17 (4.4) 0.11 (4.0) 0.10 (3.6) 0.09 (1.4) 0.04 (5.0) 0.13 (3.5) 0.09 (8.5) 0.21 (13.7) 0.34 (5.7) 0.14 (4.2) 0.11 (5.4) 0.14 (4.1) 0.10 45 (2) (2) (2) (2) (2) (2) (2) (2) (2) (2) (2) (2) (2) (2) (2) (1) (1) (1) (1)

50 none Type of Iron OxideIron of Type Corrosion Rate (mmpy (mpy))

55 Sample 1 Bn Iron oxide Corrosion of neat neat of Corrosion Average 10-34-0 1 Table from Requirements Ammonium Ammonium Polyphosphate Samples Sample 2 Bn Iron oxide Sample 3Sample 4Sample 5 Bn Iron oxide Bn Iron oxide Rd Iron oxide Sample 8Sample 10 Rd Iron oxide Sample 11Sample 12 Rd Iron oxide Sample 13 Rd Iron oxide Sample 14 Rd Iron oxide Sample 15 Rd Iron oxide Sample 16 Rd Iron oxide Sample 17 Rd Iron oxide Sample 18 Rd Iron oxide Rd Iron oxide Rd Iron oxide Sample 19 Rd Iron oxide Sample 6 Rd Iron oxide Sample 7Sample 9 Rd Iron oxide Rd Iron oxide

12 EP 1 458 449 B1

5 total

10 0.05 (1.9) 0.05 (11.1) 0.28

15 total total

20 total Diluted Solution Diluted

25 total

30 (continued) 0.05 (2.0) 0.05 (7.8) 0.20

35

40 °C (70°F) (70°F) 21°C 49°C (120°F) (120°F) 49°C (70°F) 21°C (70°F) 21°C (120°F) 49°C 49°C (120°F) 0.09 (3.7)0.09 (3.0) 0.08 (8.3) 0.21 0.16(6.4) (4.4) 0.11 (4.2) 0.11 (4.6) 0.12 (3.5) 0.09 Neat Concentrate Neat 21 total total total 0.04-0.13 0.05-0.10 0.02-0.80 0.04-0.34 0.07-0.14 0.10-0.11 0.06-0.29 0.07-0.10 (1.4-5.0) (1.9-3.8) (0.7-32.1) (1.6-13.7) (2.7-5.7) (3.9-4.3) (2.5-11.7) (2.8-4.1) 0.11 (4.4) 0.11 (2.4) 0.06 (11.2) 0.28 (2.8) 0.07 (4.1) 0.10 (4.0) 0.10 (2.3) 0.06 (2.8) 0.07 45 (2) (2) (2)

50 Type of Iron OxideIron of Type Corrosion Rate (mmpy (mpy))

55 Ammonium Ammonium Polyphosphate Samples Sample 20 Rd Iron oxide Sample 22Average Range Rd Iron oxide (1) Brown iron oxide, Lot number 5594050A, Elementis Pigments No. 8690. No. Pigments Elementis 5594050A, number Lot oxide, iron Brown (1) pigment red Kroma precipitated R03097 Pigments Elementis 5891719A, number Lot oxide, iron Red (2) Sample 21 Rd Iron oxide

13 EP 1 458 449 B1

[0049] The results indicate that the addition of small amounts of iron oxide and clay reduce the corrosion of totally immersed aluminum in a 21°C (70°F) solution by 50% to 65%. In addition, the impact of the mixture on high temperature corrosion is even more dramatic than at low temperatures. When the corrosion cell was stored at 49°C (120°F), the rate of aluminum corrosion decreased by about 75% to 90%. At both temperatures the corrosion rate on partially immersed 5 coupons was greater than 50% of the totally immersed values, which indicated that significant interface or vapor/air phase corrosion occurs when the mixture is present in the solution. This differs from the corrosivity of the neat ammonium polyphosphate solutions of Table 1. However, the addition of 1.2% insoluble iron oxide and a clay to the ammonium polyphosphate samples did not reduce the aluminum 2024- T3 corrosion rate of the concentrates or its solutions to within the limits required by the Forest Service Specifications. 10 EXAMPLE 3-THE ALUMINUM CORROSIVITY OF AMMONIUM POLYPHOSPHATE SOLUTIONS CONTAINING A MIXTURE OF SOLUBLE AND INSOLUBLE IRON COMPOUNDS

[0050] The data in Tables 3a and 3b illustrate the relative effectiveness of a number of corrosion inhibitor systems 15 containing water-soluble and water-insoluble sources of iron, and mixtures thereof, in several sources and types of ammonium polyphosphate concentrates and their diluted solutions. The samples were prepared by admixing either 10-34-0 or11-37-0 type ammonium polyphosphatesolutions from various sourceswith varying concentrations of insoluble red iron oxide or brown iron oxide additives and Attapulgus clay additives and varying the concentrations of other iron containing additives, as indicated. Samples 1, 2, 3 and 4 are 10-34-0 ammonium polyphosphate concentrates from 20 different sources. The solutions were subjected to high shear mixing in order to activate or hydrate the clay. [0051] Each concentrate and its diluted solution was tested for aluminum corrosivity in accordance with the Forest Service Specifications. The results are shown in Tables 3a and 3b.

25

30

35

40

45

50

55

14 EP 1 458 449 B1 49°C 49°C (120°F) 0.24 0.24 (9.4) 0.09 0.09 (3.5)

5 0.06 (2.5) 0.03 0.03 (1.3) 0.03 0.03 (1.0) 0.03 0.03 (1.0) 49°C 49°C (120°F) 0.02 0.02 (0.6) 0.01 0.01 (0.5) 0.40 0.40 (16.0) 0.12 0.12 (4.6)

10 21°C 21°C (70°F) 0.17 (6.9) 0.11 (4.2) Diluted Solution Diluted 21°C 21°C (70°F) 0.27 (10.8) 0.11 0.11 (4.4) 15 49°C 49°C (120°F) 1.99 1.99 (79.5) 0.16 0.16 (6.4)

20 (10.9) 0.27 (5.7) 0.14 (2.2) 0.06 49°C 49°C (120°F) (2.2) 0.06 (9.0) 3.52 (140.6) 0.23 (7.4) 0.21 (8.3) 0.19 21°C 21°C (70°F) 0.13 0.13 (5.2) 25 0.08 (3.0) °C Neat Concentrate Neat (70°F) total partial total(9.1) partial total partial total partial (3.7)

30 % sol. Table 3a Table 0.00 0.00 0.09 0.00 0.00 0.23 0.84 0.35 0.84 0.35 Fe. Content 21 0.84 0.35 0.84 0.35 insol. 0.42 0.58 0.42 0.35 % %

35

40 pyrophosphate pyrophosphate pyrophosphate pyrophosphate pyrophosphate pyrophosphate 3.0 Ferric Sol. Other Iron Containing Additive Containing Iron Other 3.0 Ferric Sol. 3.0 Ferric Sol. (%) Additive 3.0 Ferric Sol. 5.0 Ferric Sol. 0.0 None 3.0 Ferric Sol. 45

d d e e R Iron Iron oxide R Iron Iron oxide Iron Iron oxide Iron Iron oxide Iron Iron oxide oxide Iron Iron oxide 2 2 . . InsolubleIron Oxide Added %Type 1.2 Br. 0.0 None 0.0 None 1.2 Br. 0.6 Br. 1.2 Iron 50 0.6 Br.

55 Ammonium Ammonium Polyphosphate Sample (See Table 1) Table (See 81 71 Corrosion (mmpy (mpy)) (mmpy Corrosion 6 5 1 1 SAMPLE 4 2 3

15 EP 1 458 449 B1 49°C 49°C (120°F) 0.09 0.09 (3.4)

5 49°C 49°C (120°F) 0.04 (1.6) 0.04 (1.5) 0.04 (1.6) 0.02 0.02 (0.6) 0.01 (0.5) 0.04 (1.4) 0.02 (0.6) 0.04 0.04 (1.6)

10 21°C 21°C (70°F) 0.09 (3.6) Diluted Solution Diluted 21°C 21°C (70°F) 0.11 (4.4) 15 49°C 49°C (120°F) 0.07 0.07 (2.9)

20 49°C 49°C (120°F) (10.8) (10.3) (18.1) 0.27 0.26 0.45 0.15 (6.1) (6.7) (0.9) (5.5) (118.7) 0.02 0.14 0.17 3.00 21°C 21°C (70°F) 25 0.08 (3.1) °C Neat Concentrate Neat (70°F) total partial total partial total partial total partial (3.1)

30 % sol. (continued) Fe. Content 21 insol. 0.84 0.35 0.84 0.35 0.84 0.35 0.08 0.84 0.35 0.84 0.40 0.42 0.66 0.42 0.66 0.42 0.13 % %

35

40 pyrophosphate pyrophosphate* pyrophosphate* pyrophospbate citrate* citrate citrate* citrate* Other Iron Containing Additive Containing Iron Other (%) Additive 3.0 Ferric Sol. 3.0 Ferric Sol. 3.0 Ferric Sol. 3.0 Ferric Sol. 1.8 Ferric Sol. 3.0 Ferric Sol. 3.0 Ferric Sol. 0.6 Ferric Sol. 45

d e Iron Iron oxide Iron oxide Iron oxide Iron Iron oxide R Iron Iron oxide Iron Iron oxide Iron oxide Iron Iron oxide 2 . %Type InsolubleIron Oxide Added 1.2 Red 1.2 Red 1.2 Red 1.2 Br. 0.6 Br. 0.6 Br. 50 0.6 Br.

55 Ammonium Ammonium Polyphosphate Sample Corrosion (mmpy (mpy)) (mmpy Corrosion 1 0 1 1 1 2 91 1 6 1 4 1 5 1 3

16 EP 1 458 449 B1 49°C 49°C (120°F)

5 49°C 49°C (120°F) 0.02 0.02 (0.7) 0.02 (0.8) 0.09 (3.4) 0.08 0.08 (3.3) 0.06 (2.2) 0.02 (0.7) 0.02 (0.7) 0.02 (0.6)

10 21°C 21°C (70°F) Diluted Solution Diluted 21°C 21°C (70°F) 15 49°C 49°C (120°F)

20 49°C 49°C (120°F) (1.0) (7.9) (53.9) (15.3) (46.5) (1.0) (4.5) (3.9) 0.20 1.35 0.38 0.16 0.03 0.11 0.10 0.03

25 21°C (70°F) °C Neat Concentrate Neat (70°F) total partial total partial total partial total partial

30 % sol. (continued) Fe. Content 21 insol. 0.42 0.88 0.84 0.32 0.84 0.40 0.84 0.40 0.84 0.66 0.84 0.66 0.84 0.66 0.84 0.66 % %

35

40 citrate citrate citrate* citrate* citrate* citrate citrate citrate Other Iron Containing Additive Containing Iron Other (%) Additive 5.0 Sol. FerricNH4 1.8 Sol. FerricNH4 1.8 Ferric Sol. 1.8 Ferric Sol. 3.0 Ferric Sol. 3.0 Ferric Sol. 3.0 Ferric Sol. 3.0 Ferric Sol. 45 Iron Iron oxide Iron oxide Iron Iron oxide Iron oxide Iron oxide Iron oxide Iron oxide Iron oxide %Type InsolubleIron Oxide Added 0.6 Br. 1.2 Red 50 1.2 Br. 1.2 Red 1.2 Br. 1.2 Br. 1.2 Br. 1.2 Br.

55 Ammonium Ammonium Polyphosphate Sample Corrosion (mmpy (mpy)) (mmpy Corrosion 2 3 2 4 1 7 1 8 1 9 2 0 2 1 2 2

17 EP 1 458 449 B1 49°C 49°C (120°F)

5 0.03 0.03 (1.2) 0.03 0.03 (1.0) 0.02 0.02 (0.7) 0.03 0.03 (1.2) 49°C 49°C (120°F) 0.09 0.09 (3.4) 0.03 (1.3)

10 21°C 21°C (70°F) Diluted Solution Diluted 21°C 21°C (70°F) 15 49°C 49°C (120°F)

20 (2.1) 0.05 (5.8) 0.15 (2.3) 49°C 49°C (120°F) 0.06 (2.0) 0.05 (1.0) (7.5) 0.03 0.19

25 21°C (70°F) °C Neat Concentrate Neat (70°F) total partial total partial total partial total partial

30 % sol. (continued) 0.29 0.66 0.72 0.35 Fe. Content 21 0.29 0.35 insol. 0.29 0.35 0.84 0.60 1.13 0.35 % %

35

40 pyro/sol. Fe pyro/sol. citrate pyrophosphate pyrophosphate pyrophosphate sulfate•7H20 pyrophosphate 1.2/3.0 Ferric Insol. Other Iron Containing Additive Containing Iron Other 3.0/3.0 Insol./sol.Ferric 1.2/3.0 Ferric Insol./sol. (%) Additive 1.213.0 Ferric Insol./sol. 3.0 Ferrous Sol. 1.2/3.0 Ferric Insol./sol. 45 Iron Iron oxide Iron oxide %Type InsolubleIron Oxide Added 50 1.2 Red 1.2 Red

55 Ammonium Ammonium Polyphosphate Sample * These compositions contain 0.3-0.5% tolytriazole for brass corrosion inhibition corrosion brass for tolytriazole 0.3-0.5% contain compositions These * 3 0 2 9 Corrosion (mmpy (mpy)) (mmpy Corrosion 2 8 2 5 2 6 2 7

18 EP 1 458 449 B1 49°C 49°C (120°F)

5 0.04 0.04 (1.5) 0.06 0.06 (2.2) 0.03 0.03 (1.0) 0.15 (5.8) 0.04 0.04 (1.5) 0.04 0.04 (1.4) 0.03 (1.2) 0.05 (1.9) 49°C 49°C (120°F)

10 21°C 21°C (70°F) 21°C 21°C (70°F) Diluted Solution Diluted 15 49°C 49°C (120°F)

20 (1.9) 0.05 (1.9) 0.05 (2.2) 0.06 (37.4) 0.94 (3.1) 49°C 49°C (120°F) 0.08 (2.3) (1.8) (17.0) 0.06 0.05

25 21°C (70°F) °C (70°F) total partial total partial total partial total partial Neat Concentrate Neat

30 % sol. Table 3b Table 0.37 0.41 0.37 0.41 0.37 0.35 Fe. Content 21 0.37 0.60 insol. 0.37 0.35 0.37 0.70 0.37 0.70 0.37 0.35 0.43 % %

35 citrate citrate 4 4 (III) (III) (III) (III)

40 O/sol. Ferric Ferric O/sol. 2 (III) NH (III) (III) NH (III) orthophosphate/sol orthophosphate/sol Fe ortho ortho ortho/sol. Ferric Ferric ortho/sol. pyro orthophosphate/sol orthophosphate/sol Fe 2H Fe oxalate/sol. sulfate ortho/sol. Ferric Ferric ortho/sol. pyro pyrophosphate 1.2/3.0 Ferric Insol. 1.2/4.0 Insol. Fe 1.2/3.0 Ferric Insol./sol. 1.2/3.0 Ferric Insol./sol. 1.2/3.0 Insol. Ferric Other Iron Containing Additive Containing Iron Other 1.2/4.0 Insol. Fe 1.2/3.0 oxalate Fe Insol. 1.2/3.0 Insol. Fe 45 (%) Additive

50 Insoluble Oxide Iron Added %Type

55 Ammonium Polyphosphat e Sample SAMPLE 1 SAMPLE 3 5 3 4 3 3 3 2 Corrosion (mmpy (mpy)) (mmpy Corrosion 3 6 3 7 3 8 3 1

19 EP 1 458 449 B1 49°C 49°C (120°F) 0.04 0.04 (1.7) 0.09 0.09 (3.5)

5 0.01 0.01 (0.5) 49°C 49°C (120°F) 0.03 (1.1) 0.05 (1.8) 0.04 0.04 (1.4) 0.01 (0.4) 0.02 (0.8) 0.19 0.19 (7.6) 0.19 0.19 (7.6)

10 21°C 21°C (70°F) 0.09 (3.7) 0.17 (6.7) 21°C 21°C (70°F) 0.09 0.09 (3.7) 0.07 (2.8) 0.07 (2.6) 0.28 0.28 (11.0) 0.16 0.16 (6.4) Diluted Solution Diluted 15 49°C 49°C (120°F) 0.13 0.13 (5.2) 1.76 1.76 (70.2)

20 49°C 49°C (120°F) (6.2) 0.25 (10.1) 0.07 (2.8) 0.07 (2.8) (0.2) 2.75 (110.1) 1.91 (76.5) (33.2) 0.83 0.16 0.16 0.01 0.01 21°C 21°C (70°F) 0.02 0.02 (0.9) 25 0.07 (2.7) °C (70°F) total partial total partial total partial total partial (1.2) (2.8) (2.3) (1.8) (3.7) Neat Concentrate Neat

30 % sol. (continued) Fe. Content 21 insol. 0.84 0.35 0.03 0.84 0.45 0.07 0.84 0.35 0.06 0.84 0.46 0.05 0.84 0.35 0.09 0.84 0.35 % %

35

40 pyrophosphate pyrophosphate pyrophosphate pyrophosphate pyrophosphate pyrophosphate Other Iron Containing Additive Containing Iron Other 3.0 Ferric Sol. (%) Additive 3.0 Ferric Sol. 5.0 citrate Ferric Sol. 0.42 1.10 4.0 Ferric Sol. 3.0 Ferric Sol. 3.0 citrate Ferric Sol. 0.84 0.66 3.0 Ferric Sol. 45 3.0 Ferric Sol. Iron Iron oxide Iron Iron oxide Iron Iron oxide Iron Iron oxide Iron Iron oxide Iron Iron oxide Iron Iron oxide Iron Iron oxide

50 Insoluble Oxide Iron Added %Type 1.2 Br. 1.2 Red 1.2 Red 1.2 Br. 1.2 Red (2)

55 Sample Ammonium Polyphosphat e SAMPLE 2SAMPLE 1.2 Red SAMPLE 3SAMPLE 0.6 Br. 5 SAMPLE SAMPLE 4SAMPLE 1.2 Red Corrosion (mmpy (mpy)) (mmpy Corrosion 4 2 3 9 4 6 4 0 4 1 4 5 4 3 4 4

20 EP 1 458 449 B1 49°C 49°C (120°F) 0.05 0.05 (2.0) 0.11 0.11 (4.5)

5 0.03 0.03 (1.2) 0.05 (2.1) 49°C 49°C (120°F) 0.03 (1.1) 0.03 0.03 (1.1) 0.02 0.02 (0.9) 0.20 0.20 (8.1) 0.14 0.14 (5.6)

10 21°C 21°C (70°F) 0.08 (3.2) 0.16 (6.2) 21°C 21°C (70°F) 0.07 0.07 (2.7) 0.10 0.10 (3.8) 0.05 0.05 (2.0) 0.30 (11.8) 0.04 0.04 (1.6) Diluted Solution Diluted 15 49°C 49°C (120°F) 0.04 0.04 (1.7) 1.32 1.32 (52.7)

20 49°C 49°C (120°F) 0.05 (2.1) (4.0) 2.08 (83.0) 0.10 0.06 (2.4) 2.83 (113.0) 0.14 (5.4) (21.0) 0.53 21°C 21°C (70°F) 0.03 0.03 (1.0) 25 0.04 (1.7) °C (70°F) total partial total partial total partial total partial (1.4) (1.6) (2.1) (4.2) (0.6) Neat Concentrate Neat

30 % sol. (continued) Fe. Content 21 insol. 1.68 0.35 0.04 0.84 0.35 0.84 0.35 0.04 0.84 0.35 0.05 0.84 0.35 0.12 1.56 0.56 0.02 0.84 0.35 % %

35

40 pyrophosphate pyrophosphate pyrophosphate pyrophosphate pyrophosphate pyrophosphate pyrophosphate Other Iron Containing Additive Containing Iron Other (%) Additive 3.0 Ferric Sol. 3.0 Ferric Sol. 3.0 Ferric Sol. 3.0 Ferric Sol. 3.0 Ferric Sol. 3.0/3.0 Ferric Insol./sol. 45 3.0 Ferric Sol. Iron Iron oxide iron oxide Iron oxide Iron Iron oxide Iron oxide Iron Iron oxide Iron Iron oxide

50 Insoluble Oxide Iron Added %Type 2.4 Red 1.2 Red 1.2 Red 1.2 Br. 1.2 Red 1.2 Red 1.2 Red (2) (2)

55 Sample Ammonium Polyphosphat e SAMPLE 6 SAMPLE SAMPLE 7 SAMPLE Corrosion (mmpy (mpy)) (mmpy Corrosion 4 8 4 9 5 0 (1) These compositions contain 0.3-0.5% tolytriazole for brass corrosion inhibition corrosion brass for tolytriazole 0.3-0.5% contain compositions These (1) sample polyphosphate Ammonium (2) 5 1 5 2 5 3 5 4

21 EP 1 458 449 B1

[0052] For comparative purposes, line 1 illustrates the average corrosion characteristics of neat concentrate and dilute solutions from Sample 1, taken from Table 1. Line 2 illustrates the average aluminum corrosion rate of the concentrate and diluted ammonium polyphosphate (as illustrated in Table 2) when the neat material was admixed with small amounts of iron oxide pigment and Attapulgus clay. Samples 1-4 were 10-34-0 type ammonium polyphosphate samples obtained 5 from various sources. Samples 5-7 were 11-37-0 type ammonium polyphosphate samples obtained from various sources. [0053] The data in Tables 1 and 2 illustrate that corrosive attack of aluminum was most severe when exposed to the fire retardant concentrate and its solutions at elevated (120°F/49°C) temperature in the totally immersed configuration. Consequently, the evaluation of corrosion inhibiting systems stressed testing under these conditions. Periodic testing at other conditions was conducted. Lines 3 through 6 illustrate the corrosion inhibiting effectiveness of various combi- 10 nations of insoluble brown iron oxide and soluble ferric pyrophosphate. The results indicate that the Forest Service Specifications for corrosivity of fire retardants are met when 1.2% brown iron oxide is used in conjunction with 3.0% soluble ferric pyrophosphate. In addition, the results indicate that lower amounts of insoluble iron oxide result in unac- ceptable corrosion rates in the concentrated retardant solution. [0054] Lines 7 through 12 illustrate the effectiveness of corrosion inhibiting systems similar to those described in the 15 preceding paragraph, except red iron oxide is substituted for brown iron oxide. The results indicate that the red iron oxide is effective in reducing the aluminum corrosion of the concentrated and diluted ammonium polyphosphate although perhaps not quite as effective as the brown iron oxide. [0055] Lines 13-22 illustrate the corrosion inhibiting effectiveness of mixtures of water-insoluble iron oxide and water- soluble ferric citrate. The results indicate that ferric citrate is an equally effective substitute for soluble ferric pyrophosphate. 20 In addition, the results indicate that a mixture of brown iron oxide and 3.0% soluble ferric citrate is capable of reducing the corrosivity of the ammonium polyphosphate samples to within acceptable levels for compliance with Forest Service Specifications for corrosivity of fire retardants. [0056] Lines 23 and 24 illustrate the use of ferric ammonium citrate as a substitute for ferric citrate. The results indicate that the soluble ferric compounds are as effective as ammonium citrate in reducing corrosion of aluminum by ammonium 25 polyphosphate solutions. [0057] Lines 27 through 38 illustrate the effectiveness of systems in which only uncolored water-soluble and water- insoluble iron containing compounds are used rather than the relatively highly colored persistent iron oxides. This is important where true fugitive retardants are desired, whereby the color gradually fades when exposed to natural sunlight and disappears so as not to permanently stain that on which it is applied. 30 [0058] Lines 26 through 38 illustrate the effectiveness of mixtures of soluble and insoluble ferric pyrophosphate. Acceptable aluminum corrosion properties are obtained when 3.0% of the former and 1.2% of the latter are used as the corrosion inhibiting system in an ammonium polyphosphate solution. The results also indicate that an increased level of insoluble ferric pyrophosphate does not further reduce the corrosivity of the concentrate. [0059] Lines 27 though 38 illustrate the aluminum corrosion inhibiting effectiveness of mixtures of the various soluble 35 and insoluble iron compounds. Lines 37 and 38 revealed that, although effective, the tested ferrous salts were less effective at equivalent iron addition rates as compared to the ferric compounds. [0060] Lines 39 through 44 illustrate the aluminum corrosion inhibiting effectiveness of various soluble and insoluble iron compounds when used in conjunction with 10-34-0 ammonium polyphosphate concentrates obtained from alternative sources. These data indicate that the amount and ratio of corrosion inhibitor necessary to reduce corrosivity to an 40 acceptable level will need to be optimized dependent on the source and characteristics thereof. [0061] Lines 45 through 54 illustrate the aluminum corrosion inhibiting effectiveness of the subject compounds when used in various sources of 11-37-0 type ammonium polyphosphate concentrate and their diluted solutions.

EXAMPLE 4-CORROSION CHARACTERISTICS OF AMMONIUM POLYPHOSPHATE SOLUTIONS CONTAINING 45 WATER-SOLUBLE IRON COMPOUNDS

[0062] Example 4 illustrates the effectiveness of water-soluble ferric pyrophosphate, ferric citrate and ferrous sulfate as aluminum corrosion inhibitors in ammonium polyphosphate solutions. In each sample, the indicated soluble iron compounds and 1.4% Attapulgus clay were admixed with neat ammonium polyphosphate. Aliquots were subsequently 50 drawn from the concentrate and diluted with the prescribed amount of water. The aluminum corrosivity of both the concentrated fire retardants and their diluted solutions was determined in accordance with Forest Service Specifications. The results of this testing is shown in Table 4.

55

22 EP 1 458 449 B1

Table 4 Ammonium Soluble Iron Added Aluminum Corrosion(1) Polyphosphate % Additive Total Fe (%) Concentrate Dilute Solution Samples 5 Average Sample 2.67-4.25 from Table 1 0 None 0 (106.6-170.0) 0.15-0.98 (5.8-39.0) 1 0.6 Soluble ferric 0.07 3.77 (150.6) 0.04 (1.5) pyrophosphate 10 2 3.0 Soluble ferric 0.35 1.06 (42.5) 0.04 (1.6) pyrophosphate 3 3.0 Soluble ferric 0.35 1.89 (75.4) 0.03 (1.2) pyrophosphate 15 4 3.0 Soluble ferric 0.35 1.73 (69.3) 0.03 (1.3) pyrophosphate 5 2.4 Soluble ferric citrate 0.53 2.83 (113.1) 0.06 (2.5)

20 6 3.0 Soluble ferric citrate 0.66 3.10 (124.1) 0.06 (2.4) 7 3.0 Soluble ferric citrate 0.66 0.43 (17.0) 0.03 (1.1) 8 3.0 Ferrous 0.66 0.70 (27.9) 0.08 (3.1) sulfateo•7H2O 25 (1) Aluminum 2024T3 coupons tested in the manner described in USDA, Forest Service specification 5100-304b. Values obtained when the corrosion cell was maintained at 120°F (49°C) for 90 days with the coupon totally immersed therein. The data is expressed in mmpy (mpy).

[0063] The results indicate that both soluble ferric and ferrous iron containing salts show utility as aluminum corrosion 30 inhibitors in ammonium polyphosphate solutions. Relatively small concentrations (0.35%) of soluble iron derived from a soluble ferric pyrophosphate decreased the corrosion rate of totally immersed aluminum exposed to 49°C (120°F) solutions of the diluted fire retardant to within the Forest Service Specifications. The data illustrate that water-soluble iron containing compounds are most effective in controlling the corrosivity of diluted solutions. Since the corrosivity of both the concentrate and its diluted solutions is of importance, mixtures of water-soluble and water- insoluble iron com- 35 pounds generally provide superior performance.

EXAMPLE 5-CORROSION CHARACTERISTICS OF AMMONIUM POLYPHOSPHATE SOLUTIONS CONTAINING OTHER WATER-INSOLUBLE IRON COMPOUNDS

40 [0064] Table 5 illustrates the effectiveness of water-insoluble ferric orthophosphate, water-insoluble ferric pyrophosphate and ferrous oxalate as aluminum corrosion inhibitors in ammonium polyphosphate concentrates and their dilute solutions. 1.4% Attapulgus clay was mixed with the concentrated ammonium polyphosphate, with the exception of samples 6 and 7 which contained 0.7% and 2.8% Attapulgus clay, respectively. Samples 13, 18 and 24 contained, also, a water-insoluble iron oxide as a solution colorant. The resultant fire retardant concentrates and their dilute solutions 45 were evaluated in terms of aluminum corrosivity in accordance with the Forest Service Specifications. The results of the testing are shown in Table 5 below.

50

55

23 EP 1 458 449 B1 49°C 49°C (120°F) 0.24 (9.4)

5 49°C 49°C (120°F) 0.40 (16.0) 0.04 0.04 (1.7) 0.09 (3.7) 0.03 0.03 (1.1) 0.06 (2.2) 0.04 (1.4) 0.05 0.05 (2.1) 0.04 (1.7) 0.03 0.03 (1.3) 0.03 0.03 (1.1) 0.03 0.03 (1.0) 0.16 (6.3)

10 21°C 21°C (70°F) 0.17 (6.9) 21°C 21°C (70°F) 0.27 (10.8) 15 0.08 (3.1) 49°C 49°C (120°F) 1.99 (79.5)

20 0.07 0.07 0.24 0.24 0.09 0.16 0.16 0.05 0.09 49°C 49°C (120°F) 3.52 (140.6) (2.9) (9.4) 0.03 0.27 0.09 0.09 (3.5) (6.5) (2.1) 0.14 (3.6) (1.0) (3.4) (10.7) (5.5) 0.16 (6.2)

25 21°C 21°C (70°F) 0.13 (5.2) °C Neat Concentrate Diluted Solution Diluted Concentrate Neat (70°F) (9.1) Corrosion Rate (mmpy (mpy)) (mmpy Rate Corrosion (2.4)

30 Table 5 Table Fe. Content 21 0.29 0.58 0.72 0.72 0.72 0.72 0.72 0.58 0.72 0.72 0.72 0.06 0.00 0.23

35 pyrophosphate pyrophosphate pyrophosphate pyrophosphate pyrophosphate pyrophosphate pyrophosphate pyrophosphate pyrophosphate pyrophosphate pyrophosphate 40 Other Insol. Fe AdditiveFe Insol. Other Total

45 Addition 0.0 None 0.0 None % Type (%) Additive (%) total partial total partial total partial total partial

50 (1)

55 Polyphosphate Sample Ammonium Iron Oxide 110.34-0 Neat 21 Sample 0.0 None 1.2 Ferric 342 Sample 3 Sample 0.0 None 0.0 2.4 None Ferric 3.0 Ferric 564 Sample 75 Sample 0.06 Sample None 0.0 3.0 None 0.0 Ferric 3.0 None Ferric 3.0 Ferric 897 Sample 8 Sample 0.0 None 0.0 3.0 None Ferric 2.4 Ferric 1211 Sample 0.0 None 3.0 Ferric 109 Sample 1110 Sample 0.0 0.0 None 3.0 None Ferric 3.0 Ferric

24 EP 1 458 449 B1 49°C 49°C (120°F) 0.09 0.09 (3.5) 0.05 0.05 (2.0)

5 0.06 0.06 (2.2) 49°C 49°C (120°F) 0.12 0.12 (4.6) 0.02 0.02 (0.8) 0.03 (1.0) 0.02 (0.6) 0.02 0.02 (0.8) 0.02 (0.8) 0.04 (1.7) 0.10 0.10 (3.8) 0.10 (4.1)

10 21°C 21°C (70°F) 0.11 0.11 (4.2) 0.08 0.08 (3.1) 0.06 0.06 (2.4) 21°C 21°C (70°F) 0.11 0.11 (4.4) 0.04 0.04 (1.5) 0.04 (1.6) 0.06 (2.5) 15 0.03 (1.1) 0.03 (1.1) 49°C 49°C (120°F) 0.16 (6.4) 0.08 (3.0) 0.01 (0.2)

20 0.08 0.08 (3.2) 49°C 49°C (120°F) 0.21 0.21 (8.3) 0.12 0.12 (4.8) 0.16 (6.2) 0.02 (0.7) 2.63 2.63 2.70 0.23 0.23 (105.3) 0.01 0.01 (0.5) 0.07 (2.7) (108.6) (9.3)

25 21°C 21°C (70°F) 0.08 0.08 (3.0) 0.03 0.03 (1.3) 0.03 0.03 (1.2) °C Neat Concentrate Diluted Solution Diluted Concentrate Neat (70°F) (3.7) Corrosion Rate (mmpy (mpy)) (mmpy Rate Corrosion (2.0) (1.6) (2.5) (1.9) (2.1)

30 (continued) Fe. Content 21 0.72 1.56 0.05 1.56 0.04 1.56 0.06 1.56 0.05 0.16 0.55 1.56 0.05 0.73

35 pyrophosphate pyrophosphate pyrophosphate pyrophosphate pyrophosphate orthophosphate orthophosphate pyrophosphate orthophosphate 40 Other Insol. Fe AdditiveFe Insol. Other Total 0.0 None 0.84 0.09 3.0 Ferric 3.0 Ferric 3.0 Ferric 3.0 Ferric 3.0 Ferric

45 Iron Iron oxide Iron Iron oxide Iron Iron oxide Iron oxide Iron oxide Iron Iron oxide Addition 1.2 Red % Type (%) Additive (%) total partial total partial total partial total partial

50 (2)

55 Polyphosphate Sample Ammonium Iron Oxide 14 Sample 13 1312 Sample 0.0 None 3.0 Ferric 1514 Sample 1.2 Red 1615 Sample 17 1.216 Sample 18 Red 1.217 Sample Red 1.2 Red 1918 Sample 20 1.219 Sample 21 Red 20 Sample 0.0 None 0.0 1.2 None Ferric 1.8 Ferric 2221 Sample 0.0 None 2.4 Ferric

25 EP 1 458 449 B1 49°C 49°C (120°F)

5 0.11 0.11 (4.2) 49°C 49°C (120°F) 0.03 0.03 (1.0) 0.07 (2.7)

10 21°C 21°C (70°F)

15 21°C (70°F) 49°C 49°C (120°F)

20 0.04 0.04 0.06 0.06 (2.3) 49°C 49°C (120°F) (1.5) (90.0) 2.25

25 21°C 21°C (70°F) °C Neat Concentrate Diluted Solution Diluted Concentrate Neat (70°F) Corrosion Rate (mmpy (mpy)) (mmpy Rate Corrosion

30 (continued) Fe. Content 21 1.25 0.92

35 orthophosphate orthophosphate 40 Other Insol. Fe AdditiveFe Insol. Other Total 3.0 Ferric

45 Iron Iron oxide Addition % Type (%) Additive (%) total partial total partial total partial total partial

50

55 Polyphosphate Sample Ammonium Iron Oxide 24 23 Sample 1.2 Brown 2322 Sample 0.0 None 3.0 Ferric 2524 Sample 0.0 None 1.2oxalate Ferrous 0.37 (1) Average values from Table 1. Table from values Average (1) 2. Table See (2)

26 EP 1 458 449 B1

[0065] The corrosion inhibiting effectiveness of insoluble ferric pyrophosphate was shown by a comparison of the compositions containing only this component, lines 2-13, with line 1. The effectiveness was also shown by comparison with 1.2% red iron oxide, line 14. These comparisons illustrate the effectiveness of insoluble ferric pyrophosphate as an aluminum corrosion inhibitor for concentrated ammonium polyphosphate and its solutions. It was shown to be superior 5 to red iron oxide when compared on an equal ferric iron level. Accordingly, the insoluble ferric pyrophosphate would be preferred in many applications since it is not highly colored like the conventional iron oxides, which result in highly visible and persistent discoloration of that on which it is applied. Consequently, inhibitor systems containing these components would be suitable for use in fugitive colored fire retardant formulations. [0066] The data contained in lines 15-19 illustrate the further reduction in aluminum corrosion, which was obtained 10 by combining iron oxide and ferric pyrophosphate in the same corrosion inhibiting system. The results indicate that several of these formulations met the Forest Service Specifications for corrosivity of aluminum in both the concentrate and dilute forms. [0067] The data contained in lines 20 and 23 illustrate the effectiveness of insoluble ferric orthophosphate in inhibiting the corrosion of aluminum by ammonium polyphosphate solutions. The results indicate that the pyrophosphate moiety 15 may be somewhat superior to orthophosphate for inhibiting the corrosion of aluminum. [0068] The data contained in line 24 illustrate that increasing the ferric iron content of the corrosion inhibiting system by using mixtures of ferric orthophosphate and iron oxide is also an effective way of meeting the Forest Service Spec- ifications for corrosivity of aluminum. [0069] The data contained in line 25 illustrate the aluminum corrosion inhibiting effectiveness of small amounts of 20 ferrous (FeII) iron when incorporated in ammonium polyphosphate concentrates and their dilute solutions.

EXAMPLE 6-EFFECTIVENESS OF AZOLES AS CORROSION INHIBITORS IN AMMONIUM POLYPHOSPHATE FIRE RETARDANT COMPOSITIONS

25 [0070] Example 6 illustrates the effectiveness of azoles as yellow brass corrosion inhibitors in concentrated ammonium polyphosphate based fire retardant formulations and in their dilute solutions. Each sample was prepared by admixing 1.4% Attapulgus clay, 1.2% red iron oxide and the indicated azole corrosion inhibitor in the neat, concentrated ammonium polyphosphate. Subsequently, the concentrates were diluted with water in the manner described herein. The samples were then tested in accordance with Forest Service Specifications. 30 Table 6 THE IMPACT OF AZOLES ON THE CORROSION OF YELLOW BRASS EXPOSED TO CONCENTRATED AMMONIUM POLYPHOSPHATE AND ITS DILUTED SOLUTIONS.*

35 Corrosion of exposed yellow brass (mmpy (mpy)) Corrosion Concentrated Retardant Diluted Solution Inhibitor System 21 (70) 21 (70) P 49 (120) 49 (120) P 21 (70) T 21 (70) P 49 (120) 49 (120) T** T T P 40 None 0.013 0.015 0.415 0.050 0.038 (1.5) 0.143 (5.7) 0.508 0.373 (0.5) (0.6) (0.6). (2.0) (20.3) (14.9) 0.3% 0.005 0.008 tolytriazole (0.2) (0.3)

45 0.5% 0.000 0.003 0.003 0.003 0.000 (0.0) 0.000 (0.0) 0.003 0.000 tolytriazole (0.0) (0.1) (0.1) (0.1) (0.1) (0.0) 0.25% 0.005 0.003 sodium (0.2) (0.1) tolyl- 50 triazole*** 0.255% 0.005 0.003 sodium (0.2) (0.1) tolyl- 55 triazole +

27 EP 1 458 449 B1

(continued) THE IMPACT OF AZOLES ON THE CORROSION OF YELLOW BRASS EXPOSED TO CONCENTRATED AMMONIUM POLYPHOSPHATE AND ITS DILUTED SOLUTIONS.*

5 Corrosion of exposed yellow brass (mmpy (mpy)) Corrosion Concentrated Retardant Diluted Solution Inhibitor System 21 (70) 21 (70) P 49 (120) 49 (120) P 21 (70) T 21 (70) P 49 (120) 49 (120) T** T T P 10 0.425% 0.005 0.003 sodium (0.2) (0.1) tolyltriazole +

15 0.5% 0.003 0.005 sodium (0.1) (0.2) tolyltriazole*** 0.5% 0.003 0.003 0.003 0.003 0.003 (0.1) 0.008 (0.3) 0.008 20 sodium (0.1) (0.1) (0.1) (0.1) (0.3) triazole ++ 1.0% 0.003 0.003 0.003 0.003 0.003 (0.1) 0.003 (0.1) 0.003 sodium (0.1) (0.1) (0.1) (0.1) (0.1)

25 triazole ++ * 10-34-0 containing 1.4% Attapulgus clay and 1.2% red iron oxide in addition to the described inhibitor additive. ** 21 (70) and 49 (120) refer to the solution storage temperature in °C (°F), T and P refer to total or partial immersion of the metal coupon in the retardant solution during storage. *** from a 50% aqueous solution of sodium tolytriazole. 30 + from an 85% aqueous solution of sodium tolytriazole. ++ from 100% sodium triazole.

[0071] The results indicate that azoles, including both tolytriazoles and salts thereof are effective corrosion inhibitors for yellow brass in ammonium polyphosphate concentrates and solutions. These data and others included in previous 35 Examples illustrate the advantages of using azoles in conjunction with the iron containing inhibitors of this invention to reduce both aluminum and brass corrosivity of the fire retardant compositions to within desirable limits.

EXAMPLE 7 - THE IMPACT OF PHOSPHONATES ON AMMONIUM POLYPHOSPHATE TYPE FIRE RETARDANTS

40 [0072] Samples of selected commercially-available phosphonates were obtained and utilized in two studies designed to determine their impact on aluminum corrosion when blended with ammonium polyphosphate type fire retardants. In the first test series (TABLE 7A), each phosphonate was introduced at 1% based on the total ammonium polyphosphate solution. In the second test series (TABLE 7B), each phosphonate was introduced at 1% based on active phosphonic acid content. The samples were blended for 15 minutes with a laboratory stirrer fitted with a 5.08 cm (2-inch) propeller 45 blade/shaft assembly rotating at 1500-800 rpm. Each resultant solution was divided into two 0.941 (one- quart) jars filled to 800 ml ("milliliters"). The remaining solution was diluted with 4.25 parts water per part solution by volume and divided equally into two 0.941 (one- quart) jars. The first pair represented the test concentrate, while the second pair represented the test dilute solution. Two 0.94 1 (one- quart) jars were filled to 800ml with uninhibited ammonium polyphosphate type fire retardant and two one-quart jars were filled to 800 ml with ammonium polyphosphate fire retardant solution, and 50 diluted with 4.25 parts water per part fire retardant solution by volume. These uninhibited ammonium polyphosphate solutions were the standards for corrosion rate comparison. [0073] Each of the phosphonates were utilized in a second study. 1% of the phosphonic acid, based on total solution weight, was added to each ammonium polyphosphate fire retardant samples. It should be noted that "1% Tot" means 1% phosphonate, by weight; "1% Act" means 1% phosphonic acid component, by weight. All of the samples were tested 55 in accordance the above-described U.S. Forest Service corrosion testing procedures. "Change" is determined by comparing the range obtained from the uninhibited average plus or minus twice the standard deviation (2σ) of the solution average of interest. The results are shown in Tables 7C and 7D below.

28 EP 1 458 449 B1

TABLE 7A - SAMPLES CONTAINING 1% PHOSPHONATE BASED ON TOTAL AMMONIUM POLYPHOSPHATE FIRE RETARDANT Component A B C D E F G H 5 Ammonium 100.0 99.0 99.0 99.0 99.0 99.0 99.0 99.0 Polyphosphate ATMP01.0000000

10 ATMP, in conc.001.000000

Na5ATMP0001.00000 HEDP00001.0000

Na4HEDP 0 0 0 0 0 1.0 0 0 15 K6HDTMP0000001.00

Na6DTPMP00000001.0 TOTAL 100% 100% 100% 100% 100% 100% 100% 100%

20

TABLE 7B - SAMPLES CONTAINING 1% PHOSPHONATE BASED ON PHOSPHONIC ACID CONTENT Component ABCDEFGH

25 Ammonium Polyphosphate 100.0 98.0 98.0 96.55 98.33 95.24 95.65 96.0 ATMP02.0000000 ATMP, in conc. 0 0 2.0 0 0 0 0 0

Na5ATMP 0 0 0 3.45 0 0 0 0 30 HEDP 0 0 0 0 1.67 0 0 0

Na4HEDP 0 0 0 0 0 4.76 0 0

K6HDTMP0000004.350

35 Na6DTPMP00000004.0 TOTAL 100% 100% 100% 100% 100% 100% 100% 100%

40

45

50

55

29 EP 1 458 449 B1

5 Change 10 σ

15 Average 2 nd 2

20 st

25 Change 1 σ

30 Average 2 Concentrate Dilute nd

35 2 st AMMONIUM POLYPHOSPHATE AMMONIUMFIRE RETARDANT

40 TABLE 7C - THE IMPACT OF 1% PHOSPHONATE BASED PHOSPHONATE ON TOTAL OF IMPACT 1% 7C - THE TABLE 1% Tot 1% 80.6 93.4 87.0 18.1 None 3.0 4.4 3.7 1.9 Decrease 1% Tot 1% 108.3 64.4 86.3 62.1 None 3.5 4.1 3.8 0.9 Decrease 1% Tot 1% 86.7 78.1 82.4 12.2 None 2.9 3.1 3.0 0.3 Decrease 1% Tot 1% 34.8 32.0 33.4 3.9 Decrease 2.2 2.7 2.4 0.6 Decrease 1% Tot 1% 82.9 87.6 85.2 6.6 None 3.2 2.8 3.0 0.6 Decrease

45 Description 1

50 MP AT DP HE DT PMP DT Tot 1% 94.0 101.6 97.8 10.8 None 3.3 3.2 3.3 0.2 Decrease 5 4 HDT MP HDT ATMP HEDP 6 6 Na Na K Na ATMP, in conc.in ATMP, Tot 1% 104.1 78.6 91.4 36.1 None 3.8 3.6 3.7 0.2 Decrease Uninhibited Ammonium Polyphosphate Ammonium Uninhibited 74.1 89.7 81.9 22.0 None 5.0 5.1 5.0 0.1 None

55

30 EP 1 458 449 B1

TABLE 7D - THE IMPACT OF 1% PHOSPHONATE BASED ON ACTIVE PHOSPHONIC ACID CONTENT Uninhibited Ammonium 135.2 90.8 113.0 62.7 None 4.0 3.8 3.9 0.3 None Polyphosphate 5 ATMP 1% Act 151.5 125.5 138.5 36.7 None 4.3 3.3 3.8 1.4 None ATMP, in 1% Act 91.5 96.7 94.1 7.3 None 3.7 3.4 3.6 0.3 Decrease conc.

10 Na5AT MP 1% Act 125.4 131.3 128.3 8.4 None 3.6 3.9 3.7 0.3 None HEDP 1% Act 98.9 85.6 92.3 18.7 None 3.1 3.4 3.3 0.5 Decrease

Na4HE DP 1% Act 113.2 73.4 93.2 56.3 None 6.5 6.2 6.4 0.5 Increase

K6HDT 1% Act 32.5 40.1 36.3 10.8 Decrease 2.7 2.5 2.6 0.4 Decrease 15 MP

Na6DT 1% Act 122.6 127.1 124.9 6.5 None 9.8 9.0 9.4 1.2 Increase PMP

20 [0074] The results indicate that the addition of 1% K6HDTMP to ammonium polyphosphate concentrates reduced aluminum corrosion by about 60% to about 70%, dependent on use level. Accordingly, the addition of K6HDTMP significantly impacts the corrosivity of the ammonium polyphosphate concentrates. The addition of 1%6 HDTMPK also reduces the aluminum corrosivity of the dilute ammonium polyphosphate solutions by about 50%. The results indicate, however, that increasing the concentration of K6HDTMP does not improve corrosion inhibition performance in these 25 retardants.

EXAMPLE 8- AMMONIUM POLYPHOSPHATE FIRE RETARDANTS COMPRISING TOLYTRIAZOLE, ITS DERIVA- TIVES AND PHOSPHONATE

30 [0075] Samples were prepared using ammonium polyphosphate solution, attapulgus clay, red iron oxide, and K6HDTMP, tolytriazole, or Petrolite X-8089, in the amounts indicated in Table 8 below. The dry powder additives were combined and mixed prior to addition to the ammonium polyphosphate solution. The liquid additives were added sepa- rately after the powders. After all of the ingredients were added, the mixing speed was increased from 2.5 to 6, and the samples were then allowed to mix at that speed for one hour each, with the exception of the ammonium polyphosphate 35 solution only sample. The sample that comprised only the ammonium polyphosphate solution was stirred with a propeller blade attached to a hand drill After mixing for one hour, the solution viscosity was determined. When the viscosity was at least 50 centipoise ("cps"), the solution was deemed ready to use, and if not, allowed to mix an additional 15 minutes and continued in this manner until acceptable viscosity was achieved. Dilute solutions were then prepared by admixing 4.25 parts tap water with 1 part concentrate, volume to volume. The results are shown in Table 8 below. It should be 40 noted that the corrosion data presented in Table 8 are averages of duplicate samples. In addition, "21" (’’70’’) and "49" ("120") refer to the storage temperature; while "T" and "P" refer to coupon immersion, i.e., either total or partial. Solutions that did not have coupons in them were stored at room temperature.

TABLE 8 45 AMMONIUM POLYPHOSPHATE FIRE RETARDANTS COMPRISING TOLYTRIAZOLE, ITS DERIVATIVES AND PHOSPHONATATE Samples A B C* D* E* F G Components Percent in Formulation 50 Ammonium 100 97.4 96.4 93.05 88.7 95.9 95.9 Polyphosphate Clay 1.4 1.4 1.4 1.4 1.4 1.4 Red Iron Oxide 1.2 1.2 1.2 1.2 1.2 1.2 55

K6HPTMP 1.0 4.35 8.7 1.0 1.0 Tolyltriazole 0.5

31 EP 1 458 449 B1

(continued) AMMONIUM POLYPHOSPHATE FIRE RETARDANTS COMPRISING TOLYTRIAZOLE, ITS DERIVATIVES AND PHOSPHONATATE

5 Samples A B C* D* E* F G Components Percent in Formulation Petrolite X-8089 0.5 Concentrate 10 Characteristics Viscosity (CPS) 40 60 70 58 50 67 59 Corrosion

15 Aluminum 21 (70) T 12.4 4.6 2.4 4.7 5.5 4.5 5.1 21 (70) P 6.6 3.6 2.1 2.9 4.7 2.9 3.2 49 (120)T 106.6 7.3 4.7 4.6 4.3 7.7 8.5 20 49 (120) P 78.5 5.0 26.16 6.6 4.6 5.1 6.3 Yellow Brass 21 (70) T 0.8 1.1 0.4 0.5 0.7 0.0 0.1

25 21 (70) P 1.0 1.1 0.4 0.5 0.6 0.1 0.2 49 (120)T 1.1 1.0 0.4 0.4 0.6 0.1 0.1 49 (120) P 2.9 1.2 1.2 1.0 1.2 0.1 0.1 Steel 30 21 (70) T 2.4 4.6 1.2 1.3 2.3 1.3 1.4 21 (70) P 1.6 3.6 0.9 1.1 1.8 0.9 0.9 49 (120) T 2.1 7.3 0.9 1.0 1.2 1.1 1.1

35 49(120)P 1.8 5.0 1.2 1.0 1.3 1.0 1.0 Diluted Solution Characteristics

40 Viscosity (CPS) 5 8 8 8 5 8 7 Corrosion Aluminum 21 (70) T 15.2 6.7 5.1 4.2 5.0 4.9 5.6 45 21 (70) P 8.4 4.4 4.2 4.4 4.5 4.2 4.2 49 (120) T 10.1 4.0 1.8 2.4 2.4 3.1 3.1 49 (120)P 5.6 3.6 3.1 2.6 2.7 2.2 2.7

50

55

32 EP 1 458 449 B1

(continued)

Yellow Brass 21 (70) T 1.1 1.1 0.8 0.8 1.0 0.0 0.4 5 21 (70) P 4.4 4.8 4.1 3.9 4.0 0.0 0.0 49 (120)T 2.8 1.3 1.2 2.4 1.9 0.0 0.1 49 (120) P 13.5 13.9 13.7 13.0 13.6 0.0 0.1 10 Steel 21 (70) T 2.3 1.8 2.1 2.7 1.8 3.4 3.9 21 (70) P 4.1 2.1 23 2.4 2.1 2.7 2.4 49 (120) T 1.4 0.6 0.6 0.6 0.5 1.0 1.1 15 49 (120) P 2.6 1.5 13 1.1 1.2 1.4 1.5 * Formulations C, D & E with phosphonate percent in formulation of active content; @ 1% = 0.23% act., @4.35%= 1.0% act., and @ 8.7% = 2.0% act.

20 [0076] The results indicate that the addition of clay and red iron oxide dramatically reduce the aluminum corrosion of ammonium polyphosphate concentrates, but appeared to increase the corrosion of steel in ammonium polyphosphate concentrates. K6HDTMP appeared to have only a slightly positive effect on aluminum corrosion, although no difference was seen between 1.0 and 8.7%. The addition of half of a percentage of tolytriazole had a dramatic effect on yellow

25 brass corrosion, and reduced the corrosion to zero in the dilute solution. Petrolite® X-8089, at the same addition level, also had a significant positive impact on brass corrosion in both concentrate and dilute ammonium polyphosphate solutions.

30 Claims

1. A corrosion-inhibited fire retardant composition comprising:

at least one fire retardant composition comprising of at least one ammonium polyphosphate;

35 at least one suspending agent; at least one phosphonate selected from a group consisting of aminotri(methylenephosphonic acid), 1-hydroxyethylidene-1, 1-diphosphonic acid, hexamethylenediaminetetra(methylenephosphonic acid), diethylenetri- amiuepenta(methylenephosphonic acid), and salts thereof; and a corrosion inhibiting system comprising at least one corrosion inhibiting compound selected from a group of

40 corrosion inhibiting compounds consisting of azoles, insoluble ferric pyrophosphate, soluble ferric pyrophosphate, ferrous oxalate, ferric citrate, ferrous sulfate, ferric ammonium citrate, insoluble ferric orthophosphate, soluble ferric orthophosphate, ferric ammonium oxalate, ferric ammonium sulfate, ferric bromide, ferric sodium oxalate, ferric stearate, ferric sulfate, ferrous acetate, ferrous ammonium sulfate, ferrous bromide, ferrous gluconate, ferrous iodide, ferric acetate, ferric fluoroborate, ferric hydroxide, ferric oleate, ferrous fumarate, ferrous

45 oxalate, ferrous oxide, ferric lactate, and ferric resinate;

wherein said corrosion inhibiting system is present in an amount effective to reduce corrosiveness of said fire retardant composition.

50 2. The composition of claim 1 wherein said azoles are selected from a group consisting of tolytriazole, benzotriazole, mercaptobenzothiazole, dimercaptomthiadiazole, 1,2 benzisothiazoline-3-1, 2-benzimidazolone, 4,5,6,7-tetrahydrobenzotriazole, tolylimidazole, 2-(5-ethyl-2-pyridyl) benzimidazole, phthalimide, any alkali metal salts thereof and combinations thereof.

55 3. The composition of claim 1 further comprising at least one additive selected from a group consisting of coloring agents, surfactants, stabilizers, rheological modifiers, opacifying pigments and any combination thereof.

4. The composition of claim 1 wherein said corrosion inhibiting compound is at least one azole and said at least one

33 EP 1 458 449 B1

azole is present in said corrosion-inhibited fire retardant composition, in concentrate, in an amount sufficient to impart to the fire retardant composition a maximum corrosivity to yellow brass of 0.13 mm (5.0 mils) per year, as determined by the weight loss procedures specified in the Forest Service Specifications.

5 5. The composition of claim 3 wherein said coloring agent is at least one selected from a group consisting of fugitive coloring agents, non- fugitive coloring agents and pigments, extenders, opacifying pigments, and other highly colored coloring agents.

6. The composition of claim 1 wherein said at least one suspending agent is selected from a group consisting of 10 Attapulgus, Sepiolite, Fuller’s earth, Montmorillonite, Kaolin clays, and mixtures thereof.

7. The composition of claim 1 wherein said corrosion inhibiting system comprises at least one water- soluble corrosion inhibiting compound and at least one water-insoluble corrosion inhibiting compound.

15 8. The composition of claim 1 wherein said corrosion inhibiting system is present in an amount sufficient in said corrosion-inhibited fire retardant composition, in concentrate, to impart to the fire retardant composition at least one of a maximum corrosivity of aluminum to 0.13 mm (5.0 mils) per year, yellow brass to 0.13 mm (5.0 mils) per year, and steel to 0.13 mm (5.0 mils) per year, as determined by the weight loss procedures specified in the Forest Service Specifications. 20 9. The composition of claim 1, further comprising water.

10. The composition of claim 1 comprising from 0.01% to 10% by weight said corrosion inhibiting system.

25 11. The composition of claim 1 comprising from 0.30% to 6.0% by weight said corrosion inhibiting system.

12. The composition of claim 1 comprising from 0.6% to 5.0% by weight said corrosion inhibiting system.

13. The composition of claim 1 wherein said at least one phosphonate is aminotri(methylenephosphonic acid), or a salt 30 thereof.

14. The composition of claim 1 wherein said at least one phosphonate is pentasodium aminotri(methylenephosphonic acid).

35 15. The composition of claim 1 wherein said at least one phosphonate is 1-hydroxyethylidene-1, 1-diphosphonic acid, or a salt thereof.

16. The composition of claim 1 wherein said at least one phosphonate is tetrasodium 1-hydroxyethylidene- 1, 1-diphosphonic acid. 40 17. The composition of claim 1 wherein said at least one phosphonate is hexamethylenediaminetetra(methylenephosphonic acid), or a salt thereof.

18. The composition of claim 1 wherein said at least one phosphonate is hexapotassium hexamethylenediaminetetra 45 (methylenephosphonic acid).

19. The composition of claim 1 wherein said at least one phosphonate is diethylenetriazninepenta(methylenephosphonic acid), or a salt thereof.

50 20. The composition of claim 1 wherein said at least one phosphonate is hexasodium diethylenetriaminepenta (methylenephosphonic acid).

21. The composition of claim 1 wherein said composition comprises less than 10%, by weight, the at least one phosphonate, based on total ammonium polyphosphate composition. 55 22. The composition of claim 1 wherein said composition comprises from 1% to 10%, by weight, the at least one phosphonate, based on total ammonium polyphosphate composition.

34 EP 1 458 449 B1

23. The composition of claim 1 wherein said composition comprises 4.35%, by weight, the at least one phosphonate, based on total ammonium polyphosphate composition.

24. The composition of claim 3 wherein said rheological modifiers are selected from a group consisting of guar gum, 5 derivatized guar gum and xanthan gum.

25. A method of preparing a diluted corrosion-inhibited fire retardant composition adapted for application to wildland fires, the method comprising the steps of:

10 (a) forming an intermediate concentrate composition comprising the corrosion-inhibited fire retardant composition of claim 1; and (b) diluting said intermediate concentrate with water to form said diluted corrosion-inhibited fire retardant composition.

15 26. The method of claim 25 wherein said azoles are selected from a group consisting of tolytriazole, benzotriazole, mercaptobenzothiazole, dimercaptomthiadiazole, 1,2 benzisothiazoline-3-1, 2-benzimidazolone, 4,5,6,7-tetrahydrobenzotriazole, tolylimidazole, 2-(5-ethyl-2-pyridyl) benzimidazole, phthalimide, any alkali metal salts thereof and combinations thereof.

20 27. The method of claim 25 wherein said corrosion inhibiting system comprises at least one water-soluble corrosion inhibiting compound and at least one water-insoluble corrosion inhibiting compound.

28. The method of claim 25 wherein said intermediate concentrate composition further comprises at least one additive selected from a group of additives consisting of coloring agents, surfactants, stabilizers, rheological modifiers, 25 opacifying pigments and any combination thereof.

29. The method of claim 25 wherein said corrosion inhibiting system comprises at least one azole and said azole is present in said corrosion- inhibited fire retardant composition, in concentrate, in an amount sufficient to impart to the corrosion-inhibited fire retardant composition a maximum corrosivity of yellow brass to 0.13 mm (5.0 mils) per year, 30 as determined by the weight loss procedures specified in the Forest Service Specifications.

30. The method of claim 25 wherein said corrosion inhibiting system is present in an amount sufficient to impart to the corrosion-inhibited fire retardant composition, in concentrate, a maximum corrosivity of aluminum to 0.13 mm (5.0 mils) per year, brass to 0.13 mm (5.0 mils) per year, and steel to 0.13 mm (5.0 mils) per year, as determined by the 35 weight loss procedures specified in the Forest Service Specifications.

31. The method of claim 25 wherein said diluted corrosion- inhibited fire retardant composition has a maximum corrosivity of aluminum to 0.05 mm (2.0 mils) per year, of brass to 0.05 mm (2.0 mils) per year, and of steel to 0.05 mm (2.0 mils) per year when tested in the totally immersed condition and to 0.13 mm (5.0 mils) per year when tested in the 40 partially immersed condition, as determined by the weight loss procedures specified in the Forest Service Specifi- cations.

32. The method of claim 28 wherein said coloring agent is selected from a group of coloring agents consisting of fugitive coloring agents, non- fugitive coloring agents and pigments, extenders, opacifying pigments, and other highly colored 45 coloring agents.

33. The method of claim 25 wherein said suspending agent is selected from a group of suspending agents consisting of Attapulgus clay, Sepiolite, Fuller’s earth, Montmorillonite, Kaolin clays, and mixtures thereof.

50 34. The method of claim 25 wherein said at least one phosphonate is aminotri(methylenephosphonic acid), or a salt thereof.

35. The method of claim 25 wherein said at least one phosphonate is pentasodium aminotri(methylenephosphonic acid).

55 36. The method of claim 25 wherein said at least one phosphonate is 1-hydroxyethylidene- 1,1-diphosphonic acid, or a salt thereof.

37. The method of claim 25 wherein said at least one phosphonate is tetrasodium 1-hydroxyethylidene- 1,1-diphosphonic

35 EP 1 458 449 B1

acid.

38. The method of claim 25 wherein said at least one phosphonate is hexamethylenediaminetetra(methylenephosphonic acid), or a salt thereof. 5 39. The method of claim 25 wherein said at least one phosphonate is hexapotassium hexamethylenediaminetetra (methylenephosphonic acid).

40. The method of claim 25 wherein said at least one phosphonate is diethylenetriaminepenta(methylenephosphonic 10 acid), or a salt thereof.

41. The method of claim 25 wherein said at least one phosphonate is hexasodium diethylenetriaminepenta(methylenephosphonic acid).

15 42. The method of claim 25 wherein said corrosion-inhibited fire retardant composition comprises less than 10%, by weight, said at least one phosphonate, based on total intermediate concentrate composition.

43. The method of claim 25 wherein said corrosion-inhibited fire retardant composition comprises from 1.0% to 10%, by weight, said at least one phosphonate, based on total intermediate concentrate composition. 20 44. The method of claim 25 wherein said corrosion-inhibited fire retardant composition comprises 4.35%, by weight, said at least one phosphonate, based on total intermediate concentrate composition.

45. The method of claim 28 wherein said rheological modifying agent is at least one selected from a group consisting 25 of guar gum, derivatized guar gum and xanthan gum.

46. A method of suppressing wildland fires comprising aerially applying to wildland vegetation a fire suppressing composition comprising:

30 water; and the corrosion-inhibited fire retardant composition of claim 1.

47. The method of claim 46 wherein said azoles are selected from a group consisting of tolytriazole, benzotriazole, mercaptobenzothiazole, dimercaptomthiadiazole, 1,2 benzisothiazoline-3-1, 2-benzimidazolone, 4,5,6,7-tetrahyd- 35 robenzotriazole, tolylimidazole, 2-(5-ethyl-2-pyridyl) benzimidazole, phthalimide, any alkali metal salts thereof and combinations thereof.

48. The method of claim 46 further comprising at least one additive selected from a group consisting of coloring agents, surfactants, stabilizers, rheological modifiers, opacifying pigments, and any combination thereof. 40 49. The method of claim 46 wherein said corrosion inhibitor is an azole and said azole is present in said corrosion- inhibited fire retardant composition, in concentrate, in an amount sufficient to impart to the corrosion-inhibited fire retardant composition a corrosivity of yellow brass to a maximum of 0.13 mm (5.0 mils) per year, as determined by the weight loss procedures specified by the Forest Service Specifications. 45 50. The method of claim 48 wherein said coloring agent is at least one selected from a group consisting of fugitive coloring agents, non- fugitive coloring agents and pigments, extenders, opacifying pigments, and other highly colored coloring agents.

50 51. The method of claim 46 wherein said at least one suspending agent is selected from a group of suspending agents consisting of Attapulgus clay, Sepiolite, Fuller’s earth, Montmorillonite, Kaolin clays, and mixtures thereof.

52. The method of claim 46 wherein said corrosion inhibiting system is comprised of at least one water- soluble corrosion inhibiting compound and at least one water-insoluble corrosion inhibiting compound. 55 53. The method of claim 46 wherein said corrosion inhibiting system is present in an amount sufficient to impart to the corrosion-inhibited fire retardant composition, in concentrate, a maximum corrosivity of aluminum to 0.13 mm (5.0 mils) per year, brass to 0.13 mm (5.0 mils) per year, and steel to 0.13 (5.0 mils) per year, as determined by the

36 EP 1 458 449 B1

weight loss procedures specified by the Forest Service Specifications.

54. The method of claim 46 wherein said corrosion- inhibited fire retardant composition comprises from 0.01% to 10.0% said corrosion inhibiting system. 5 55. The method of claim 46 wherein said corrosion-inhibited fire retardant composition comprises from 0.30% to 6.0% said corrosion inhibiting system.

56. The method of claim 46 wherein said corrosion-inhibited fire retardant composition comprises from 0.60% to 5.0% 10 said corrosion inhibiting system.

57. The method of claim 48 wherein said rheological modifier is at least one selected from a group consisting of guar gum, derivatized guar gum and xanthan gum.

15 58. A method of inhibiting corrosion comprising contacting a corrodible material with the corrosion inhibited composition of claim 1.

59. The method of claim 58 wherein said azoles are selected from a group consisting of tolytriazole, benzotriazole, mercaptobenzothiazole, dimercaptomthiadiazole, 1,2 benzisothiazoline-3-1, 2-benzimidazolone, 4,5,6,7-tetrahyd- 20 robenzotriazole, tolylimidazole, 2-(5-ethyl-2-pyridyl) benzimidazole, phthalimide, any alkali metal salts thereof and combinations thereof.

60. The method of claim 58 wherein said corrosion inhibited composition comprises at least one water-soluble corrosion inhibiting compound and at least one water-insoluble corrosion inhibiting compound. 25 61. The method of claim 58 wherein said corrosion inhibited composition further comprises at least one additive selected from a group consisting of coloring agents, opacifying pigments, surfactants, stabilizers, rheological modifiers, and any combination thereof.

30 62. The method of claim 58 wherein said corrodible material is at least one material selected from a group consisting of steel, brass and aluminum.

63. The method of claim 58 wherein said at least one corrosion inhibited fire retardant further comprises water.

35 64. The method of claim 58 wherein said suspending agent is at least one suspending agent selected from a group consisting of Attapulgus clay, Fuller’s earth, Montmorillonite, Sepiolite Kaolin clays, and mixtures thereof.

65. The method of claim 58 wherein said at least one phosphonate is aminotri(methylenephosphonic acid), or a salt thereof. 40 66. The method of claim 58 wherein said at least one phosphonate is pentasodium aminotri(methylenephosphonic acid).

67. The method of claim 58 wherein said at least one phosphonate is 1-hydroxyethylidene- 1,1-diphosphonic acid, or a salt thereof. 45 68. The method of claim 58 wherein said at least one phosphonate is tetrasodium 1-hydroxyethylidene- 1,1-diphosphonic acid.

69. The method of claim 58 wherein said at least one phosphonate is hexamethylenediaminetetra(methylenephosphonic 50 acid), or a salt thereof.

70. The method of claim 58 wherein said at least one phosphonate is hexapotassium hexamethylenediaminetetra (methylenephosphonic acid).

55 71. The method of claim 58 wherein said at least one phosphonate is diethylenetriaminepenta(methylenephosphonic acid), or a salt thereof.

72. The method of claim 58 wherein said at least one phosphonate is hexasodium diethylenetriaminepenta(methyl-

37 EP 1 458 449 B1

enephosphonic acid).

73. The method of claim 58 wherein said corrosion inhibited composition comprises less than 10%, by weight, said at least one phosphonate, based on total corrosion-inhibited composition. 5 74. The method of claim 58 wherein said corrosion inhibited composition comprises from 1% to 10%, by weight, said at least one phosphonate, based on total corrosion-inhibited composition.

75. The method of claim 58 wherein said corrosion inhibited composition comprises 4.35%, by weight, said at least one 10 phosphonate, based on total corrosion-inhibited composition.

76. The method of claim 61 wherein said rheological modifier is at least one selected from a group consisting of guar gum, derivatized guar gum and xanthan gum.

15 77. The method of claim 61 wherein said coloring agent is at least one selected from a group consisting of fugitive coloring agents, non- fugitive coloring agents and pigments, extenders, opacifying pigments, and other highly colored coloring agents.

78. A corrosion-inhibited agricultural plant nutrient comprising: 20 at least one agricultural plant nutrient; at least one suspending agent; at least one phosphonate selected from a group consisting of aminotri(methylenephosphonic acid), 1-hydroxyethylidene-1,1-diphosphonic acid, hexamethylenediaminetetra(methylenephosphonic acid), diethylenetri- 25 aminepenta(methylenephosphonic acid), salts thereof, and mixtures thereof; and a corrosion inhibiting system comprised of at least one corrosion inhibiting compound selected from a group of corrosion inhibiting compounds consisting of azoles, insoluble ferric pyrophosphate, soluble ferric pyrophosphate, ferrous oxalate, ferric citrate, ferrous sulfate, ferric ammonium citrate, insoluble ferric orthophosphate, soluble ferric orthophosphate, ferric ammonium oxalate, ferric ammonium sulfate, ferric bromide, ferric sodium 30 oxalate, ferric stearate, ferric sulfate, ferrous acetate, ferrous ammonium sulfate, ferrous bromide, ferrous gluconate, ferrous iodide, ferric acetate, ferric fluoroborate, ferric hydroxide, ferric oleate, ferrous fumarate, ferrous oxalate, ferrous oxide, ferric lactate, ferric resinate and any combination thereof;

wherein said corrosion inhibiting system is present in an amount effective to reduce corrosiveness of said agricultural 35 plant nutrient over that which said agricultural plant nutrient would exhibit in the absence of said corrosion inhibiting system.

Patentansprüche 40 1. Korrosionsinhibierte flammhemmende Zusammensetzung, umfassend:

mindestens eine flammhemmende Zusammensetzung, umfassend mindestens ein Ammoniumpolyphosphat; mindestens ein Suspendierungsmittel; 45 mindestens ein Phosphonat, ausgewählt aus der Gruppe, bestehend aus Aminotri(methylenphosphonsäure), 1-Hydroxyethyliden-1,1-diphosphonsäure, Hexamethylendiamintetra(methylenphosphonsäure), Diethylentria- minpenta(methylenphosphonsäure) und Salzen davon, und ein korrosionsinhibierendes System, umfassend mindestens eine korrosionsinhibierende Verbindung, ausge- wählt aus der Gruppe von korrosionsinhibierenden Verbindungen, bestehend aus Azolen, unlöslichem Eisen 50 (III)-pyrophosphat, löslichem Eisen(III)-pyrophosphat, Eisen(II)-oxalat, Eisen(III)-citrat, Eisen(II)-sulfat, Eisen (III)-ammoniumcitrat, unlöslichem Eisen(III)-orthophosphat, löslichem Eisen(III)-orthophosphat, Eisen(III)-ammoniumoxalat, Eisen(III)-ammoniumsulfat, Eisen(III)-bromid, Eisen(III)-natriumoxalat, Eisen(III)-stearat, Eisen (III)-sulfat, Eisen(II)-acetat, Eisen(II)-ammoniumsulfat, Eisen(II)-bromid, Eisen(II)-gluconat, Eisen(II)-iodid, Ei- sen(III)-acetat, Eisen(III)-fluorborat, Eisen(III)-hydroxid, Eisen(III)-oleat, Eisen(II)-fumarat, Eisen(II)-oxalat, Ei- 55 sen(II)-oxid, Eisen(III)-lactat und Eisen(III)-resinat;

worin das korrosionsinhibierende System in einer Menge vorliegt, die zur Verringerung der Korrosivität der flammhemmenden Zusammensetzung wirksam ist.

38 EP 1 458 449 B1

2. Zusammensetzung nach Anspruch 1, worin die Azole ausgewählt sind aus der Gruppe, bestehend aus Tolytriazol, Benzotriazol, Mercaptobenzothiazol, Dimercaptomthiadiazol, 1,2- Benzisothiazolin-3-1,2-benzimidazolon, 4, 5, 6, 7- Tetrahydrobenzotriazol, Tolylimidazol, 2-(5-Ethyl-2-pyridyl)benzimidazol, Phthalimid, Alkalimetallsalzen davon und Kombinationen davon. 5 3. Zusammensetzung nach Anspruch 1, weiterhin umfassend mindestens ein Additiv, ausgewählt aus der Gruppe, bestehend aus Färbehilfsmitteln, Tensiden, Stabilisatoren, rheologischen Modifiziermitteln, deckenden Pigmenten und Kombinationen davon.

10 4. Zusammensetzung nach Anspruch 1, worin die korrosionsinhibierende Verbindung mindestens ein Azol ist und das mindestens eine Azol in der korrosionsinhibierten flammhemmenden Zusammensetzung im Konzentrat in einer Menge vorliegt, die ausreichend ist, um der flammhemmenden Zusammensetzung eine maximale Korrosivität ge- genüber Messingguss von 0,13 mm (5,0 mils) pro Jahr zu verleihen, wie sie durch die Gewichtsverlustverfahren bestimmt wird, die in den Forest Service Specifications spezifiziert sind. 15 5. Zusammensetzung nach Anspruch 3, worin das Färbehilfsmittel mindestens eines ist, das aus der Gruppe, bestehend aus flüchtigen Färbehilfsmitteln, nicht-flüchtigen Färbehilfsmitteln und Pigmenten, Streckmitteln, deckenden Pigmenten und anderen hochgefärbten Färbehilfsmitteln, ausgewählt ist.

20 6. Zusammensetzung nach Anspruch 1, worin das mindestens eine Suspendierungsmittel ausgewählt ist aus der Gruppe, bestehend aus Attapulgit, Sepiolit, Fuller-Erde, Montmorillonit, Kaolintonen und Gemischen davon.

7. Zusammensetzung nach Anspruch 1, worin das korrosionsinhibierende System mindestens eine wasserlösliche korrosionsinhibierende Verbindung und mindestens eine wasserunlösliche korrosionsinhibierende Verbindung um- 25 fasst.

8. Zusammensetzung nach Anspruch 1, worin das korrosionsinhibierende System in einer Menge in der korrosionsinhibierten flammhemmenden Zusammensetzung im Konzentrat vorliegt, die ausreichend ist, um der flammhemmenden Zusammensetzung mindestens eine einer Maximalkorrosivität gegenüber Aluminium von 0,13 mm (5,0 30 mils) pro Jahr, gegenüber Messingguss von 0,13 mm (5,0 mils) pro Jahr und gegenüber Stahl von 0,13 mm (5,0 mils) pro Jahr zu verleihen, wie sie durch die Gewichtsverlustverfahren bestimmt wird, die in den Forest Service Specifications spezifiziert sind.

9. Zusammensetzung nach Anspruch 1, weiterhin umfassend Wasser. 35 10. Zusammensetzung nach Anspruch 1, umfassend 0,01 bis 10 Gew.-% des korrosionsinhibierenden Systems.

11. Zusammensetzung nach Anspruch 1, umfassend 0,30 bis 6,0 Gew.-% des korrosionsinhibierenden Systems.

40 12. Zusammensetzung nach Anspruch 1, umfassend 0,6 bis 5,0 Gew.-% des korrosionsinhibierenden Systems.

13. Zusammensetzung nach Anspruch 1, worin das mindestens eine Phosphonat Aminotri(methylenphosphonsäure) oder ein Salz davon ist.

45 14. Zusammensetzung nach Anspruch 1, worin das mindestens eine Phosphonat Pentanatriumaminotri(methylenphos- phonsäure) ist.

15. Zusammensetzung nach Anspruch 1, worin das mindestens eine Phosphonat 1-Hydroxyethyliden- 1,1-diphosphon- säure oder ein Salz davon ist. 50 16. Zusammensetzung nach Anspruch 1, worin das mindestens eine Phosphonat Tetranatrium-1-hydroxyethyliden- 1,1-diphosphonsäure ist.

17. Zusammensetzung nach Anspruch 1, worin das mindestens eine Phosphonat Hexamethylendiamintetra (methylen- 55 phosphonsäure) oder ein Salz davon ist.

18. Zusammensetzung nach Anspruch 1, worin das mindestens eine Phosphonat Hexakaliumhexamethylendiamintetra (methylenphosphonsäure) ist.

39 EP 1 458 449 B1

19. Zusammensetzung nach Anspruch 1, worin das mindestens eine Phosphonat Diethylentriaminpenta (methylenphos- phonsäure) oder ein Salz davon ist.

20. Zusammensetzung nach Anspruch 1, worin das mindestens eine Phosphonat Hexanatriumdiethylentriaminpenta 5 (methylenphosphonsäure) ist.

21. Zusammensetzung nach Anspruch 1, worin die Zusammensetzung weniger als 10 Gew.-% des mindestens einen Phosphonats, bezogen auf die gesamte Ammoniumpolyphosphatzusammensetzung, umfasst.

10 22. Zusammensetzung nach Anspruch 1, worin die Zusammensetzung von 1 bis 10 Gew.-% des mindestens einen Phosphonats, bezogen auf die gesamte Ammoniumpolyphosphatzusammensetzung, umfasst.

23. Zusammensetzung nach Anspruch 1, worin die Zusammensetzung 4,35 Gew.-% des mindestens einen Phospho- nats, bezogen auf die gesamte Ammoniumpolyphosphatzusammensetzung, umfasst. 15 24. Zusammensetzung nach Anspruch 3, worin die rheologischen Modifiziermittel ausgewählt sind aus der Gruppe, bestehend aus Guar-Gum, derivatisiertem Guar-Gum und Xanthanlösung.

25. Verfahren zur Herstellung einer verdünnten korrosionsinhibierten flammhemmenden Zusammensetzung, eingestellt 20 zur Anwendung bei Freilandbränden, umfassend die Stufen:

(a) des Herstellens einer Zwischenkonzentratzusammensetzung, umfassend die korrosionsinhibierte flammhemmende Zusammensetzung nach Anspruch 1 und (b) des Verdünnens des Zwischenkonzentrats mit Wasser zur Herstellung der verdünnten korrosionsinhibierten 25 flammhemmenden Zusammensetzung.

26. Verfahren nach Anspruch 25, worin die Azole ausgewählt sind aus der Gruppe, bestehend aus Tolytriazol, Ben- zotriazol, Mercaptobenzothiazol, Dimercaptomthiadiazol, 1,2-Benzisothiazolin-3-1,2-benzimidazolon, 4,5,6,7-Te- trahydrobenzotriazol, Tolylimidazol, 2-(5-Ethyl-2-pyridyl)benzimidazol, Phthalimid, Alkalimetallsalzen davon und 30 Kombinationen davon.

27. Verfahren nach Anspruch 25, worin das korrosionsinhibierende System mindestens eine wasserlösliche korrosionsinhibierende Verbindung und mindestens eine wasserunlösliche korrosionsinhibierende Verbindung umfasst.

35 28. Verfahren nach Anspruch 25, worin die Zwischenkonzentratzusammensetzung weiterhin mindestens ein Additiv, ausgewählt aus der Gruppe, bestehend aus Färbehilfsmitteln, Tensiden, Stabilisatoren, rheologischen Modifizier- mitteln, deckenden Pigmenten und Kombinationen davon, umfasst.

29. Verfahren nach Anspruch 25, worin das korrosionsinhibierende System mindestens ein Azol umfasst und das Azol 40 in der korrosionsinhibierten flammhemmenden Zusammensetzung im Konzentrat in einer Menge vorliegt, die ausreichend ist, um der korrosionsinhibierten flammhemmenden Zusammensetzung eine maximale Korrosivität ge- genüber Messingguss von 0,13 mm (5,0 mils) pro Jahr zu verleihen, wie sie durch die Gewichtsverlustverfahren bestimmt wird, die in den Forest Service Specifications spezifiziert sind.

45 30. Verfahren nach Anspruch 25, worin das korrosionsinhibierende System in einer Menge vorliegt, die ausreichend ist, um der korrosionsinhibierten flammhemmenden Zusammensetzung im Konzentrat mindestens eine einer Ma- ximalkorrosivität gegenüber Aluminium von 0,13 mm (5,0 mils) pro Jahr, gegenüber Messingguss von 0,13 mm (5,0 mils) pro Jahr und gegenüber Stahl von 0,13 mm (5,0 mils) pro Jahr zu verleihen, wie sie durch die Gewichtsver- lustverfahren bestimmt wird, die in den Forest Service Specifications spezifiziert sind. 50 31. Verfahren nach Anspruch 25, worin die verdünnte korrosionsinhibierte flammhemmende Zusammensetzung eine Maximalkorrosivität gegenüber Aluminium von 0,05 mm (2,0 mils) pro Jahr, gegenüber Messingguss von 0,05 mm (2,0 mils) pro Jahr und gegenüber Stahl von 0,13 mm (5,0 mils) pro Jahr hat, wenn diese im teilweise eingetauchten Zustand untersucht werden, wie sie durch die Gewichtsverlustverfahren bestimmt wird, die in den Forest Service 55 Specifications spezifiziert sind.

32. Verfahren nach Anspruch 28, worin das Färbehilfsmittel aus der Gruppe, bestehend aus flüchtigen Färbehilfsmitteln, nicht-flüchtigen Färbehilfsmitteln und Pigmenten, Streckmitteln, deckenden Pigmenten und anderen hochgefärbten

40 EP 1 458 449 B1

Färbehilfsmitteln, ausgewählt ist.

33. Verfahren nach Anspruch 25, worin das Suspendierungsmittel ausgewählt ist aus der Gruppe, bestehend aus Attapulgit-Ton, Sepiolit, Fuller-Erde, Montmorillonit, Kaolintonen und Gemischen davon. 5 34. Verfahren nach Anspruch 25, worin das mindestens eine Phosphonat Aminotri(methylenphosphonsäure) oder ein Salz davon ist.

35. Verfahren nach Anspruch 25, worin das mindestens eine Phosphonat Pentanatriumaminotri(methylenphosphon- 10 säure) ist.

36. Verfahren nach Anspruch 25, worin das mindestens eine Phosphonat 1-Hydroxyethyliden-1,1-diphosphonsäure oder ein Salz davon ist.

15 37. Verfahren nach Anspruch 25, worin das mindestens eine Phosphonat Tetranatrium- 1-hydroxyethyliden-1,1-diphos- phonsäure ist.

38. Verfahren nach Anspruch 25, worin das mindestens eine Phosphonat Hexamethylendiamintetra(methylenphos- phonsäure) oder ein Salz davon ist. 20 39. Verfahren nach Anspruch 25, worin das mindestens eine Phosphonat Hexakaliumhexamethylendiamintetra(methy- lenphosphonsäure) ist.

40. Verfahren nach Anspruch 25, worin das mindestens eine Phosphonat Diethylentriaminpenta(methylenphosphon- 25 säure) oder ein Salz davon ist.

41. Verfahren nach Anspruch 25, worin das mindestens eine Phosphonat Hexanatriumdiethylentriaminpenta(methy- lenphosphonsäure) ist.

30 42. Verfahren nach Anspruch 25, worin die korrosionsinhibierte flammhemmende Zusammensetzung weniger als 10 Gew.-% des mindestens einen Phosphonats, bezogen auf die gesamte Zwischenkonzentratzusammensetzung, umfasst.

43. Verfahren nach Anspruch 25, worin die korrosionsinhibierte flammhemmende Zusammensetzung von 1 bis 10 35 Gew.-% des mindestens einen Phosphonats, bezogen auf die gesamte Zwischenkonzentratzusammensetzung, umfasst.

44. Verfahren nach Anspruch 25, worin die korrosionsinhibierte flammhemmende Zusammensetzung 4,35 Gew.-% des mindestens einen Phosphonats, bezogen auf die gesamte Zwischenkonzentratzusammensetzung, umfasst. 40 45. Verfahren nach Anspruch 25, worin das rheologische Modifiziermittel mindestens eines ist, ausgewählt aus der Gruppe, bestehend aus Guar-Gum, derivatisiertem Guar-Gum und Xanthanlösung.

46. Verfahren zur Bekämpfung von Freilandbränden, umfassend das Ausbringen einer feuerbekämpfenden Zusam- 45 mensetzung aus der Luft auf die Freilandvegetation, die umfasst:

Wasser und die korrosionsinhibierte flammhemmende Zusammensetzung nach Anspruch 1.

50 47. Verfahren nach Anspruch 46, worin die Azole ausgewählt sind aus der Gruppe, bestehend aus Tolytriazol, Ben- zotriazol, Mercaptobenzothiazol, Dimercaptomthiadiazol, 1,2-Benzisothiazolin-3-1,2-benzimidazolon, 4,5,6,7-Te- trahydrobenzotriazol, Tolylimidazol, 2-(5-Ethyl-2-pyridyl)benzimidazol, Phthalimid, Alkalimetallsalzen davon und Kombinationen davon.

55 48. Verfahren nach Anspruch 46, weiterhin umfassend mindestens ein Additiv, ausgewählt aus der Gruppe, bestehend aus Färbehilfsmitteln, Tensiden, Stabilisatoren, rheologischen Modifiziermitteln, deckenden Pigmenten und Kom- binationen davon.

41 EP 1 458 449 B1

49. Verfahren nach Anspruch 46, worin die korrosionsinhibierende Verbindung mindestens ein Azol ist und das Azol in der korrosionsinhibierten flammhemmenden Zusammensetzung im Konzentrat in einer Menge vorliegt, die ausreichend ist, um der korrosionsinhibierten flammhemmenden Zusammensetzung eine Korrosivität gegenüber Mes- singguss von 0,13 mm (5,0 mils) maximal pro Jahr zu verleihen, wie sie durch die Gewichtsverlustverfahren bestimmt 5 wird, die in den Forest Service Specifications spezifiziert sind.

50. Verfahren nach Anspruch 48, worin das Färbehilfsmittel mindestens eines ist, das aus der Gruppe, bestehend aus flüchtigen Färbehilfsmitteln, nicht-flüchtigen Färbehilfsmitteln und Pigmenten, Streckmitteln, deckenden Pigmenten und anderen hochgefärbten Färbehilfsmitteln, ausgewählt ist. 10 51. Verfahren nach Anspruch 46, worin das mindestens eine Suspendierungsmittel ausgewählt ist aus einer Gruppe von Suspendierungsmitteln, bestehend aus Attapulgit-Ton, Sepiolit, Fuller-Erde, Montmorillonit, Kaolintonen und Gemischen davon.

15 52. Verfahren nach Anspruch 46, worin das korrosionsinhibierende System aus mindestens einer wasserlöslichen korrosionsinhibierenden Verbindung und mindestens einer wasserunlöslichen korrosionsinhibierenden Verbindung besteht.

53. Verfahren nach Anspruch 46, worin das korrosionsinhibierende System in einer Menge vorliegt, die ausreichend 20 ist, um der korrosionsinhibierten flammhemmenden Zusammensetzung im Konzentrat mindestens eine einer Ma- ximalkorrosivität gegenüber Aluminium von 0,13 mm (5,0 mils) pro Jahr, gegenüber Messingguss von 0,13 mm (5,0 mils) pro Jahr und gegenüber Stahl von 0,13 mm (5,0 mils) pro Jahr zu verleihen, wie sie durch die Gewichtsver- lustverfahren bestimmt wird, die in den Forest Service Specifications spezifiziert sind.

25 54. Verfahren nach Anspruch 46, worin die korrosionsinhibierte flammhemmende Zusammensetzung 0,01 bis 10% des korrosionsinhibierenden Systems umfasst.

55. Verfahren nach Anspruch 46, worin die korrosionsinhibierte flammhemmende Zusammensetzung 0,30 bis 6,0% des korrosionsinhibierenden Systems umfasst. 30 56. Verfahren nach Anspruch 46, worin die korrosionsinhibierte flammhemmende Zusammensetzung 0,60 bis 5,0% des korrosionsinhibierenden Systems umfasst.

57. Verfahren nach Anspruch 48, worin das rheologische Modifiziermittel mindestens eines ist, ausgewählt aus der 35 Gruppe, bestehend aus Guar-Gum, derivatisiertem Guar-Gum und Xanthanlösung.

58. Verfahren zur Inhibierung von Korrosion, umfassend das Inkontaktbringen eines korrodierbaren Materials mit der korrosionsinhibierten Zusammensetzung nach Anspruch 1.

40 59. Verfahren nach Anspruch 58, worin die Azole ausgewählt sind aus der Gruppe, bestehend aus Tolytriazol, Ben- zotriazol, Mercaptobenzothiazol, Dimercaptomthiadiazol, 1,2-Benzisothiazolin-3-1,2-benzimidazolon, 4,5,6,7-Te- trahydrobenzotriazol, Tolylimidazol, 2-(5-Ethyl-2-pyridyl)benzimidazol, Phthalimid, Alkalimetallsalzen davon und Kombinationen davon.

45 60. Verfahren nach Anspruch 58, worin die korrosionsinhibierte Zusammensetzung mindestens eine wasserlösliche korrosionsinhibierende Verbindung und mindestens eine wasserunlösliche korrosionsinhibierende Verbindung umfasst.

61. Verfahren nach Anspruch 58, worin die korrosionsinhibierte Zusammensetzung weiterhin mindestens ein Additiv, 50 ausgewählt aus der Gruppe, bestehend aus Färbehilfsmitteln, Tensiden, Stabilisatoren, rheologischen Modifizier- mitteln, deckenden Pigmenten und Kombinationen davon, umfasst.

62. Verfahren nach Anspruch 58, worin das korrodierbare Material mindestens ein Material, ausgewählt aus der Gruppe, bestehend aus Stahl, Messing und Aluminium, ist. 55 63. Verfahren nach Anspruch 58, worin das mindestens eine korrosionsinhibierte flammhemmende Mittel weiterhin Wasser umfasst.

42 EP 1 458 449 B1

64. Verfahren nach Anspruch 58, worin das Suspendierungsmittel mindestens ein Suspendierungsmittel, ausgewählt aus der Gruppe, bestehend aus Attapulgit-Ton, Sepiolit, Fuller-Erde, Montmorillonit, Kaolintonen und Gemischen davon, ist.

5 65. Verfahren nach Anspruch 58, worin das mindestens eine Phosphonat Aminotri(methylenphosphonsäure) oder ein Salz davon ist.

66. Verfahren nach Anspruch 58, worin das mindestens eine Phosphonat Pentanatriumaminotri(methylenphosphon- säure) ist. 10 67. Verfahren nach Anspruch 58, worin das mindestens eine Phosphonat 1-Hydroxyethyliden-1,1-diphosphonsäure oder ein Salz davon ist.

68. Verfahren nach Anspruch 58, worin das mindestens eine Phosphonat Tetranatrium- 1-hydroxyethyliden-1,1-diphos- 15 phonsäure ist.

69. Verfahren nach Anspruch 58, worin das mindestens eine Phosphonat Hexamethylendiamintetra(methylenphos- phonsäure) oder ein Salz davon ist.

20 70. Verfahren nach Anspruch 58, worin das mindestens eine Phosphonat Hexakaliumhexamethylendiamintetra(methy- lenphosphonsäure) ist.

71. Verfahren nach Anspruch 58, worin das mindestens eine Phosphonat Diethylentriaminpenta(methylenphosphon- säure) oder ein Salz davon ist. 25 72. Verfahren nach Anspruch 58, worin das mindestens eine Phosphonat Hexanatriumdiethylentriaminpenta(methy- lenphosphonsäure) ist.

73. Verfahren nach Anspruch 58, worin die korrosionsinhibierte Zusammensetzung weniger als 10 Gew.-% des min- 30 destens einen Phosphonats, bezogen auf die gesamte korrosionsinhibierte Zusammensetzung, umfasst.

74. Verfahren nach Anspruch 58, worin die korrosionsinhibierte Zusammensetzung von 1 bis 10 Gew.- % des mindestens einen Phosphonats, bezogen auf die gesamte korrosionsinhibierte Zusammensetzung, umfasst.

35 75. Verfahren nach Anspruch 58, worin die korrosionsinhibierte Zusammensetzung 4,35 Gew.-% des mindestens einen Phosphonats, bezogen auf die gesamte korrosionsinhibierte Zusammensetzung, umfasst.

76. Verfahren nach Anspruch 61, worin das rheologische Modifiziermittel mindestens eines ist, ausgewählt aus der Gruppe, bestehend aus Guar-Gum, derivatisiertem Guar-Gum und Xanthanlösung. 40 77. Verfahren nach Anspruch 61, worin das Färbehilfsmittel mindestens eines ist, das aus der Gruppe, bestehend aus flüchtigen Färbehilfsmitteln, nicht-flüchtigen Färbehilfsmitteln und Pigmenten, Streckmitteln, deckenden Pigmenten und anderen hochgefärbten Färbehilfsmitteln, ausgewählt ist.

45 78. Korrosionsinhibierter landwirtschaftlicher Pflanzennährstoff, umfassend:

mindestens einen landwirtschaftlichen Pflanzennährstoff, mindestens ein Suspendierungsmittel, mindestens ein Phosphonat, ausgewählt aus der Gruppe, bestehend aus Aminotri(methylenphosphonsäure), 50 1-Hydroxyethyliden-1,1-diphosphonsäure, Hexamethylendiamintetra(methylenphosphonsäure), Diethylentria- minpenta(methylenphosphonsäure), Salzen davon und Gemischen davon und ein korrosionsinhibierendes System, bestehend aus mindestens einer korrosionsinhibierenden Verbindung, ausgewählt aus der Gruppe von korrosionsinhibierenden Verbindungen, bestehend aus Azolen, unlöslichem Eisen(III)-pyrophosphat, löslichem Eisen(III)-pyrophosphat, Eisen (II)-oxalat, Eisen(III)-citrat, Eisen(II)-sulfat, Ei- 55 sen(III)-ammoniumcitrat, unlöslichem Eisen(III)-orthophosphat, löslichem Eisen(III)-orthophosphat, Eisen (III)-ammoniumoxalat, Eisen(III)-ammoniumsulfat, Eisen(III)-bromid, Eisen(III)-natriumoxalat, Eisen(III)-stearat, Eisen(III)-sulfat, Eisen(II)-acetat, Eisen(II)-ammoniumsulfat, Eisen(II)-bromid, Eisen(II)-gluconat, Eisen (II)-iodid, Eisen(III)-acetat, Eisen(III)-fluorborat, Eisen(III)-hydroxid, Eisen(III)-oleat, Eisen(II)-fumarat, Eisen

43 EP 1 458 449 B1

(II)-oxalat, Eisen(II)-oxid, Eisen(III)-lactat und Eisen(III)-resinat und Kombinationen davon;

worin das korrosionsinhibierende System in einer Menge vorliegt, die wirksam ist, um die Korrosivität des landwirtschaftlichen Pflanzennährstoffs gegenüber derjenigen zu verringern, die der landwirtschaftliche Pflanzennährstoff 5 in Abwesenheit des korrosionsinhibierenden Systems zeigen würde.

Revendications

10 1. Composition ignifuge, inhibée en corrosion, comprenant :

au moins une composition ignifuge comprenant au moins un polyphosphate d’ammonium ; au moins un agent de mise en suspension ; au moins un phosphonate sélectionné parmi un groupe constitué de l’aminotri (acide méthylènephosphonique), 15 de l’acide 1-hydroxyéthylidène-1,1-diphosphonique, de l’hexaméthylènediaminetétra(acide méthylènephos- phonique), du diéthylènetriaminepenta(acide méthylènephosphonique), et de sels de ces derniers ; et un système inhibant la corrosion, comprenant au moins un composé inhibant la corrosion, sélectionné parmi un groupe constitué des azoles, du pyrophosphate ferrique insoluble, du pyrophosphate ferrique soluble, de l’oxalate ferreux, du citrate ferrique, du sulfate ferreux, du citrate d’ammonium ferrique, de l’orthophosphate 20 ferrique insoluble, de l’orthophosphate ferrique soluble, de l’oxalate d’ammonium ferrique, du sulfate d’ammonium ferrique, du bromure ferrique, de l’oxalate de sodium ferrique, du stéarate ferrique, du sulfate ferrique, de l’acétate ferreux, du sulfate d’ammonium ferreux, du bromure ferreux, du gluconate ferreux, de l’iodure ferreux, de l’acétate ferrique, du fluoroborate ferrique, de l’hydroxyde ferrique, de l’oléate ferrique, du fumarate ferreux, de l’oxalate ferreux, de l’oxyde ferreux, du lactate ferrique et du résinate ferrique ; 25 dans laquelle ledit système inhibant la corrosion est présent dans une quantité efficace pour réduire la corrosivité de ladite composition ignifuge.

2. Composition selon la revendication 1, dans laquelle lesdits azoles sont sélectionnés parmi un groupe constitué du 30 tolytriazole, du benzotriazole, du mercaptobenzothiazole, du dimercaptothiadiazole, du 1,2 benzisothiazoline- 3-1,2- benzimidazolone, du 4,5,6,7-tétrahydrobenzotriazole, du tolylimidazole, du 2-(5-éthyl- 2-pyridinyl)benzimidazole, du phtalimide, de l’un quelconque des sels de métaux alcalins de ces derniers et de combinaisons de ces derniers.

3. Composition selon la revendication 1, comprenant en outre au moins un additif sélectionné parmi un groupe constitué 35 d’agents colorants, d’agents tensioactifs, d’agents stabilisants, d’agents modificateurs de la rhéologie, de pigments opacifiants et d’une combinaison quelconque de ces derniers.

4. Composition selon la revendication 1, dans laquelle ledit composé inhibant la corrosion est au moins un azole et ledit au moins un azole est présent dans ladite composition ignifuge, inhibée en corrosion, sous forme concentrée, 40 dans une quantité suffisante pour conférer à la composition ignifuge une corrosivité maximale vis-à-vis du laiton jaune de 0,13 mm (5,0 millièmes de pouce) par an, comme déterminé par les procédures de perte de poids spécifiées dans les spécifications du Service des Forêts.

5. Composition selon la revendication 3, dans laquelle ledit agent colorant est au moins un agent sélectionné parmi 45 ungroupe constitué d’agents colorants fugitifs, d’agents colorants non fugitifs et de pigments, de diluants, de pigments opacifiants et d’autres agents colorants fortement colorés.

6. Composition selon la revendication 1, dans laquelle ledit au moins un agent de mise en suspension est sélectionné parmi un groupe constitué de l’attapulgite, de la sépiolite, de la terre à foulon, de la montmorillonite, d’argiles de 50 kaolin et de mélanges de ces derniers.

7. Composition selon la revendication 1, dans laquelle ledit système inhibant la corrosion comprend au moins un composé inhibant la corrosion hydrosoluble et au moins un composé inhibant la corrosion non hydrosoluble.

55 8. Composition selon la revendication 1, dans laquelle ledit système inhibant la corrosion est présent dans une quantité suffisante dans ladite composition ignifuge, inhibée en corrosion, sous forme concentrée, pour conférer à la composition ignifuge au moins l’une des corrosivités maximales vis-à-vis de l’aluminium de 0,13 mm (5,0 millièmes de pouce) par année, vis-à-vis du laiton jaune de 0,13 mm (5,0 millièmes de pouce) par année, et vis-à-vis de l’acier

44 EP 1 458 449 B1

de 0,13 mm (5,0 millièmes de pouce) par année, comme déterminé par les procédures de perte de poids spécifiés dans les spécifications du Service des Forêts.

9. Composition selon la revendication 1, comprenant en outre l’eau. 5 10. Composition selon la revendication 1, comprenant de 0,01 % à 10 % en poids dudit système inhibant la corrosion.

11. Composition selon la revendication 1, comprenant de 0,30 % à 6,0 % en poids dudit système inhibant la corrosion.

10 12. Composition selon la revendication 1, comprenant de 0,6 % à 5,0 % en poids dudit système inhibant la corrosion.

13. Composition selon la revendication 1, dans laquelle ledit au moins un phosphonate est l’aminotri(acide méthylène- phosphonique) ou un sel de ce dernier.

15 14. Composition selon la revendication 1, dans laquelle ledit au moins un phosphonate est le sel pentasodique de l’aminotri(acide méthylènephosphonique).

15. Composition selon la revendication 1, dans laquelle ledit au moins un phosphonate est l’acide 1-hydroxyéthylidène- 1,1-diphosphonique ou un sel de ce dernier. 20 16. Composition selon la revendication 1, dans laquelle ledit au moins un phosphonate est le sel tétrasodique de l’acide 1-hydroxyéthylidène-1,1-diphosphonique.

17. Composition selon la revendication 1, dans laquelle ledit au moins un phosphonate est l’hexaméthylènediaminetétra 25 (acide méthylènephosphonique), ou un sel de ce dernier.

18. Composition selon la revendication 1, dans laquelle ledit au moins un phosphonate est le sel hexapotassique de l’hexaméthylènediaminetétra(acide méthylènephosphonique).

30 19. Composition selon la revendication 1, dans laquelle ledit au moins un phosphonate est le diéthylènetriaminepenta (acide méthylènephosphonique), ou un sel de ce dernier.

20. Composition selon la revendication 1, dans laquelle ledit au moins un phosphonate est le sel hexasodique du diéthylènetriaminepenta(acide méthylènephosphonique). 35 21. Composition selon la revendication 1, dans laquelle ladite composition comprend moins de 10 % en poids du au moins un phosphonate, sur la base de la composition totale de polyphosphate d’ammonium.

22. Composition selon la revendication 1, dans laquelle ladite composition comprend de 1 à 10 % en poids du au moins 40 un phosphonate, sur la base de la composition totale de polyphosphate d’ammonium.

23. Composition selon la revendication 1, dans laquelle ladite composition comprend 4,35 % en poids du au moins un phosphonate, sur la base de la composition totale de polyphosphate d’ammonium.

45 24. Composition selon la revendication 3, dans laquelle lesdits agents modificateurs de la rhéologie sont sélectionnés parmi un groupe constitué de la gomme de guar, de la gomme de guar dérivée et de la gomme de xanthane.

25. Procédé de préparation d’une composition ignifuge, inhibée en corrosion, diluée, adaptée à l’application contre les feux de végétation, le procédé comprenant les étapes : 50 (a) de formation d’une composition de concentré intermédiaire comprenant la composition ignifuge, inhibée en corrosion, selon la revendication 1 ; et (b) de dilution dudit concentré intermédiaire à l’aide d’eau pour former ladite composition ignifuge, inhibée en corrosion. 55 26. Procédé selon la revendication 25, dans lequel lesdits azoles sont sélectionnés parmi un groupe constitué du tolytriazole, du benzotriazole, du mercaptobenzothiazole, du dimercaptothiadiazole, du 1,2 benzisothiazoline- 3-1,2- benzimidazolone, du 4,5,6,7-tétrahydrobenzotriazole, du tolylimidazole, du 2-(5-éthyl-2-pyridyl)benzimidazole, du

45 EP 1 458 449 B1

phtalimide, de l’un quelconque des sels de métaux alcalins de ces derniers et de combinaisons de ces derniers.

27. Procédé selon la revendication 25, dans lequel ledit système inhibant la corrosion comprend au moins un composé inhibant la corrosion hydrosoluble et au moins un composé inhibant la corrosion non hydrosoluble. 5 28. Composition selon la revendication 25, dans laquelle ladite composition de concentré intermédiaire comprend en outre au moins un additif sélectionné parmi un groupe d’additifs constitué d’agents colorants, d’agents tensioactifs, d’agents stabilisants, d’agents modificateurs de la rhéologie, de pigments opacifiants et d’une combinaison quelconque de ces derniers. 10 29. Procédé selon la revendication 25, dans lequel ledit système inhibant la corrosion comprend au moins un azole et dans lequel ledit azole est présent dans ladite composition ignifuge, inhibée en corrosion, sous forme concentrée, dans une quantité suffisante pour conférer à la composition ignifuge, inhibée en corrosion, une corrosivité maximale vis-à-vis du laiton jaune de 0,13 mm (5,0 millièmes de pouce) par an, comme déterminé par les procédures de perte 15 de poids spécifiées dans les spécifications du Service des Forêts.

30. Procédé selon la revendication 25, dans laquelle ledit système inhibant la corrosion est présent dans une quantité suffisante pour conférer à la composition ignifuge, inhibée en corrosion, sous forme concentrée, une corrosivité maximale vis-à-vis de l’aluminium de 0,13 mm (5,0 millièmes de pouce) par année, vis- à-vis du laiton de 0,13 mm 20 (5,0 millièmes de pouce) par année, et vis-à- vis de l’acier de 0,13 mm (5,0 millièmes de pouce) par année, comme déterminé par les procédures de perte de poids spécifiées dans les spécifications du Service des Forêts.

31. Procédé selon la revendication 25, dans lequel ladite composition ignifuge, inhibée en corrosion, diluée, a une corrosivité maximale vis-à-vis de l’aluminium de 0,05 mm (2,0 millièmes de pouce) par année, vis-à-vis du laiton 25 de 0,05 mm (2,0 millièmes de pouce) par année, et vis-à-vis de l’acier de 0,05 mm (2,0 millièmes de pouce) par année, en cas de mise à l’essai dans des conditions totalement immergées et de 0,13 mm (5,0 millièmes de pouce) par année en cas de mise à l’essai dans des conditions partiellement immergées, comme déterminé par les pro- cédures de perte de poids spécifiées dans les spécifications du Service des Forêts.

30 32. Procédéselon la revendication 28, dans lequel ledit agent colorant est sélectionné parmi un groupe d’agents colorants constitué d’agents colorants fugitifs, d’agents colorants non fugitifs et de pigments, de diluants, de pigments opacifiants et d’autres agents colorants fortement colorés.

33. Procédé selon la revendication 25, dans lequel ledit agent de mise en suspension est sélectionné parmi un groupe 35 d’agents de mise en suspension constitué de l’attapulgite, de la sépiolite, de la terre à foulon, de la montmorillonite, d’argiles de kaolin et de mélanges de ces derniers.

34. Procédé selon la revendication 25, dans lequel ledit au moins un phosphonate est l’aminotri(acide méthylènephos- phonique), ou un sel de ce dernier. 40 35. Procédé selon la revendication 25, dans lequel ledit au moins un phosphonate est le sel pentasodique de l’aminotri (acide méthylènephosphonique).

36. Procédé selon la revendication 25, dans lequel ledit au moins un phosphonate est l’acide 1-hydroxyéthylidène- 1,1- 45 diphosphonique, ou un sel de ce dernier.

37. Procédé selon la revendication 25, dans lequel ledit au moins un phosphonate est le sel tétrasodique de l’acide 1- hydroxyéthylidène-1,1-diphosphonique.

50 38. Procédé selon la revendication 25, dans lequel ledit au moins un phosphonate est l’hexaméthylènediaminetétra (acide méthylènephosphonique), ou un sel de ce dernier.

39. Procédé selon la revendication 25, dans lequel ledit au moins un phosphonate est le sel hexapotassique de l’hexa- méthylènediaminetétra(acide méthylènephosphonique). 55 40. Procédé selon la revendication 25, dans lequel ledit au moins un phosphonate est le diéthylènetriaminepenta (acide méthylènephosphonique), ou un sel de ce dernier.

46 EP 1 458 449 B1

41. Procédé selon la revendication 25, dans lequel ledit au moins un phosphonate est le sel hexasodique du diéthylè- netriaminepenta(acide méthylènephosphonique).

42. Procédé selon la revendication 25, dans lequel ladite composition ignifuge, inhibée en corrosion, comprend moins 5 de 10 % en poids dudit au moins un phosphonate, sur la base de la composition de concentré intermédiaire totale.

43. Procédé selon la revendication 25, dans lequel ladite composition ignifuge, inhibée en corrosion, comprend de 0,1 à de 10 % en poids dudit au moins un phosphonate, sur la base de la composition de concentré intermédiaire totale.

10 44. Procédé selon la revendication 25, dans lequel ladite composition ignifuge, inhibée en corrosion, comprend 4,35 % en poids dudit au moins un phosphonate, sur la base de la composition de concentré intermédiaire totale.

45. Procédé selon la revendication 28, dans lequel ledit agent modificateur de la rhéologie est au moins un agent modificateur sélectionné parmi un groupe constitué de la gomme de guar, de la gomme de guar dérivée et de la 15 gomme de xanthane.

46. Procédé de suppression des feux de végétation comprenant l’application par voie aérienne à des feux de végétation d’une composition ignifuge comprenant :

20 de l’eau ; et la composition ignifuge, inhibée en corrosion, selon la revendication 1.

47. Procédé selon la revendication 46, dans laquelle lesdits azoles sont sélectionnés parmi un groupe constitué du tolytriazole, du benzotriazole, du mercaptobenzothiazole, du dimercaptothiadiazole, du 1,2 benzisothiazoline- 3-1,2- 25 benzimidazolone, du 4,5,6,7-tétrahydrobenzotriazole, du tolylimidazole, du 2-(5-éthyl-2-pyridyl)benzimidazole, du phthalimide, de l’un quelconque des sels de métaux alcalins de ces derniers et de combinaisons de ces derniers.

48. Procédé selon la revendication 46, comprenant en outre au moins un additif sélectionné parmi un groupe constitué d’agents colorants, d’agents tensioactifs, d’agents stabilisants, d’agents modificateurs de la rhéologie, de pigments 30 opacifiants et d’une combinaison quelconque de ces derniers.

49. Procédé selon la revendication 46, dans lequel ledit agent inhibiteur de la corrosion est un azole et dans lequel ledit azole est présent dans ladite composition ignifuge, inhibée en corrosion, sous forme concentrée, dans une quantité suffisante pour conférer à la composition ignifuge, inhibée en corrosion, une corrosivité maximale vis-à- vis du laiton 35 jaune de 0,13 mm (5,0 millièmes de pouce) par an, comme déterminé par les procédures de perte de poids spécifiées dans les spécifications du Service des Forêts.

50. Procédé selon la revendication 48, dans lequel ledit agent colorant est au moins un agent sélectionné parmi un groupe constitué d’agents colorants fugitifs, d’agents colorants non fugitifs et de pigments, de diluants, de pigments 40 opacifiants et d’autres agents colorants fortement colorés.

51. Procédé selon la revendication 46, dans lequel ledit agent de mise en suspension est sélectionné parmi un groupe d’agents de mise en suspension constitué de l’attapulgite, de la sépiolite, de la terre à foulon, de la montmorillonite, d’argiles de kaolin et de mélanges de ces derniers. 45 52. Procédé selon la revendication 46, dans lequel ledit système inhibant la corrosion comprend au moins un composé inhibant la corrosion hydrosoluble et au moins un composé inhibant la corrosion non hydrosoluble.

53. Procédé selon la revendication 46, dans lequel ledit système inhibant la corrosion est présent dans une quantité 50 suffisante pour conférer à la composition ignifuge, inhibée en corrosion, sous forme concentrée, une corrosivité maximale vis-à-vis de l’aluminium de 0,13 mm (5,0 millièmes de pouce) par année, vis- à-vis du laiton de 0,13 mm (5,0 millièmes de pouce) par année, et vis-à- vis de l’acier de 0,13 mm (5,0 millièmes de pouce) par année, comme déterminé par les procédures de perte de poids spécifiées dans les spécifications du Service des Forêts.

55 54. Procédé selon la revendication 46, dans lequel ladite composition ignifuge, inhibée en corrosion, comprend de 0,01 % à 10,0 % dudit système inhibant la -corrosion.

55. Procédé selon la revendication 46, dans lequel ladite composition ignifuge, inhibée en corrosion, comprend de 0,30

47 EP 1 458 449 B1

% à 6,0 % dudit système inhibant la corrosion.

56. Procédé selon la revendication 46, dans lequel ladite composition ignifuge, inhibée en corrosion, comprend de 0,60 % à 5,0 % dudit système inhibant la corrosion. 5 57. Procédé selon la revendication 48, dans lequel ledit agent modificateur de la rhéologie est au moins un agent modificateur sélectionné parmi un groupe constitué de la gomme de guar, de la gomme de guar dérivée et de la gomme de xanthane.

10 58. Procédé d’inhibition de la corrosion comprenant la mise en contact d’un matériau capable d’être corrodé avec la composition inhibée en corrosion, selon la revendication 1.

59. Procédé selon la revendication 58, dans lequel lesdits azoles sont sélectionnés parmi un groupe constitué du tolytriazole, du benzotriazole, du mercaptobenzothiazole, de la dimercaptothiadiazole, de la 1,2 benzisothiazoline- 15 3-1,2-benzimidazolone, du 4,5,6,7-tétrahydrobenzotriazole, du tolylimidazole, du 2-(5-éthyl- 2-pyridyl)benzimidazole, du phthalimide, de l’un quelconque des sels de métaux alcalins de ces dernierset de combinaisonsde ces derniers.

60. Procédé selon la revendication 58, dans lequel ladite composition inhibée en corrosion comprend au moins un composé inhibant la corrosion hydrosoluble et au moins un composé inhibant la corrosion non hydrosoluble. 20 61. Procédé selon la revendication 58, dans lequel ladite composition inhibée en corrosion, comprend en outre au moins un additif sélectionné parmi un groupe constitué d’agents colorants, de pigments opacifiants, d’agents tensioactifs, d’agents stabilisants, d’agents modificateurs de la rhéologie, et d’une combinaison quelconque de ces derniers.

25 62. Procédé selon la revendication 58, dans lequel ledit matériau pouvant être corrodé est au moins un matériau sélectionné parmi un groupe constitué de l’acier, du laiton et de l’aluminium.

63. Procédé selon la revendication 58, dans lequel ladite au moins une composition ignifuge inhibée en corrosion comprend en outre de l’eau. 30 64. Procédé selon la revendication 58, dans lequel ledit agent de mise en suspension est au moins un agent de mise en suspension sélectionné parmi un groupe constitué de l’attapulgite, de la terre à foulon, de la montmorillonite, d’argiles de kaolin et de mélanges de ces derniers.

35 65. Procédé selon la revendication 58, dans lequel ledit au moins un phosphonate est l’aminotri(acide méthylènephos- phonique), ou un sel de ce dernier.

66. Procédé selon la revendication 58, dans lequel ledit au moins un phosphonate est le sel pentasodique de l’aminotri (acide méthylènephosphonique). 40 67. Procédé selon la revendication 58, dans lequel ledit au moins un phosphonate est l’acide 1-hydroxyéthylidène- 1,1- diphosphonique, ou un sel de ce dernier.

68. Procédé selon la revendication 58, dans lequel ledit au moins un phosphonate est le sel tétrasodique de l’acide 1- 45 hydroxyéthylidène-1,1-diphosphonique.

69. Procédé selon la revendication 58, dans lequel ledit au moins un phosphonate est l’hexaméthylènediaminetétra (acide méthylènephosphonique) ou un sel de ce dernier.

50 70. Procédé selon la revendication 58, dans lequel ledit au moins un phosphonate est le sel hexapotassique de l’hexa- méthylènediaminetétra(acide méthylènephosphonique).

71. Procédé selon la revendication 58, dans lequel ledit au moins un phosphonate est le diéthylènetriaminepenta (acide méthylènephosphonique) ou un sel de ce dernier. 55 72. Procédé selon la revendication 58, dans lequel ledit au moins un phosphonate est le sel hexasodique du diéthylè- netriaminepenta(acide méthylènephosphonique).

48 EP 1 458 449 B1

73. Procédé selon la revendication 58, dans lequel ladite composition inhibée en corrosion, comprend moins de 10 % en poids dudit au moins un phosphonate, sur la base de la composition inhibée en corrosion totale.

74. Procédé selon la revendication 58, dans lequel ladite composition inhibée en corrosion, comprend de 1 % à 10 % 5 en poids dudit au moins un phosphonate, sur la base de la composition inhibée en corrosion totale.

75. Procédé selon la revendication 58, dans lequel ladite composition inhibée en corrosion comprend 4,35 % en poids dudit au moins un phosphonate, sur la base de la composition inhibée en corrosion totale.

10 76. Procédé selon la revendication 61, dans lequel ledit agent modificateur de la rhéologie est au moins un agent modificateur sélectionné parmi un groupe constitué de la gomme de guar, de la gomme de guar dérivée et de la gomme de xanthane.

77. Procédé selon la revendication 61, dans lequel ledit agent colorant est au moins un agent sélectionné parmi un 15 groupe constitué d’agents colorants fugitifs, d’agents colorants non fugitifs et de pigments, de diluants, de pigments opacifiants et d’autres agents colorants fortement colorés.

78. Milieu nutritif d’usine agricole, inhibé en corrosion, comprenant :

20 au moins un milieu nutritif d’usine agricole ; au moins un agent de mise en suspension ; au moins un phosphonate sélectionné parmi un groupe constitué de l’aminotri (acide méthylènephosphonique), de l’acide 1-hydroxyéthylidène-1,1-diphosphonique, de l’hexaméthylènediaminetétra(acide méthylènephos- phonique), du diéthylènetriaminepenta (acide méthylènephosphonique), de sels de ces derniers; et de mélanges 25 de ces derniers ; et d’un système inhibant la corrosion comprenant au moins un composé inhibant la corrosion sélectionné parmi le groupe constitué des azoles, du pyrophosphate ferrique insoluble, du pyrophosphate ferrique soluble, de l’oxalate ferreux, du citrate ferrique, du sulfate ferreux, du citrate d’ammonium ferrique, de l’orthophosphate ferrique insoluble, de l’orthophosphate ferrique soluble, de l’oxalate d’ammonium ferrique, du sulfate d’ammo- 30 nium ferrique, du bromure ferrique, de l’oxalate de sodium ferrique, du stéarate ferrique, du sulfate ferrique, de l’acétate ferreux, du sulfate d’ammonium ferreux, du bromure ferreux, du gluconate ferreux, de l’iodure ferreux, de l’acétate ferrique, du fluoroborate ferrique, de l’hydroxyde ferrique, de l’oléate ferrique, du fumarate ferreux, de l’oxalate ferreux, de l’oxyde ferreux, du lactate ferrique, du résinate ferrique et de combinaisons quelconques de ces derniers ; 35 dans lequel ledit système inhibant la corrosion est présent dans une quantité efficace pour réduire la corrosivité dudit milieu nutritif d’usine agricole au-delà de ce que ledit milieu nutritif d’usine agricole manifesterait en l’absence dudit système inhibant la corrosion.

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49 EP 1 458 449 B1

REFERENCES CITED IN THE DESCRIPTION

This list of references cited by the applicant is for the reader’s convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

Patent documents cited in the description

• US 4839065 A, Vandersall [0036]

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