WO2014138568A1

WO2014138568A1 - Activated peroxide compositions for anti-microbial applications

Info

Publication number: WO2014138568A1
Application number: PCT/US2014/021694
Authority: WO
Inventors: Deqing Lei; George Polson; Qi ZHENG; Nicole WISE
Original assignee: Arch Chemicals, Inc.
Priority date: 2013-03-07
Filing date: 2014-03-07
Publication date: 2014-09-12

Abstract

An antimicrobial composition contains hydrogen peroxide and/or an organic peroxyacid in combination with peroxytungstic acid. In one embodiment, the composition further contains an organic acid and tungstic acid. The antimicrobial composition is very effective at sanitizing surfaces in all different types of fields, such as in the food service industry and in the healthcare industry. The antimicrobial composition is also well suited for controlling algae.

Description

ACTIVATED PEROXIDE COMPOSITIONS FOR

ANTI-MICROBIAL APPLICATIONS

BACKGROUND

[001] Antimicrobial compositions are used in numerous and diverse applications. In general, antimicrobial compositions are used to destroy

microorganisms and/or prevent the growth of microorganisms. Antimicrobial compositions are used, for instance, to disinfect or sanitize surfaces and objects in the food service industry, in the healthcare industry, in industrial settings, and for consumer household use. In one embodiment, antimicrobial compositions are used to sanitize or disinfect surfaces, such as hard, non-porous surfaces.

Antimicrobial compositions are also used for algae control in recreational and pond waters.

[002] Some antimicrobial compositions are known to contain hydrogen peroxide. Hydrogen peroxide has advantages and benefits to being used as a disinfectant and biocide because it decomposes to oxygen and water and therefore is very safe to use. Another advantage to hydrogen peroxide is that it has a broad spectrum of biocidal activities against many different types of organisms. Unfortunately, however, hydrogen peroxide, when used alone, can have a relatively low rate of activity.

[003] For example, a 6% aqueous hydrogen peroxide solution only provides about a 3 log reduction against Staphloccus aureus, and less than a 2 log reduction against Pseudomonas aeruginosa after 5 minutes of contact time. A 6000 ppm hydrogen peroxide solution can only achieve about a 1 log reduction and less than a 1 log reduction against staphylococcus and pseudomonas after 5 minutes of contact time, respectively. The killing efficiency of hydrogen peroxide can be improved by using a higher concentration of hydrogen peroxide or a longer contact time. Compositions containing concentrated amounts of hydrogen peroxide, however, can be corrosive and unstable. In addition, contact times of longer than 5 minutes are not practical or acceptable for many applications.

[004] In view of the above, those skilled in the art have attempted to produce antimicrobial solutions containing hydrogen peroxide that have enhanced biocide properties. In particular, those skilled in the art have attempted to produce hydrogen peroxide solutions with improved efficacy and killing rate against a variety of microorganisms. In this regard, in the past, hydrogen peroxide has been reacted with acids to produce peroxyacids for use as microbiocidal agents. The peroxyacids, for instance, can generate hydroperoxyl radicals that provide the antimicrobial properties.

[005] Peracetic acid (PAA), as an activated hydrogen peroxide, is one of the most widely used peroxyacids for disinfecting and inhibiting rapid bacterial growth. PAA is commonly used to kill bacteria in the dairy industry, to control microbial growth in process waters in the pulp and paper industry and for bleaching paper pulps. PAA is also used to control algae growth in ponds and other water bodies. However, PAA compositions generally contain acetic acid causing the compositions to possess a very strong odor, especially when concentrated.

[006] To minimize odor and improve antimicrobial activity, many other peroxyacid compositions for controlling microbial populations have been

developed. For example, U.S. Pat. Nos. 4,501 ,058; 5,200,189; 5,314,687;

5,409,713; 5,437,868; 5,489,434; 5,718,910; 6,010,729; 6,514,556; 6,627,657; 7,816,555; and 8,263,151 , which are all incorporated herein by reference, disclose a variety of peroxyacid compositions including short, medium chain and hydroxyl- peroxycarboxylic acids.

[007] Some commercially available peroxyacid compositions are equilibrium mixtures comprising hydrogen peroxide, peroxyacid and an organic acid together with a small amount of stabilizers and acid catalysts, such as sulfuric acid or sodium hydrogen sulfate. The peroxyacid compositions are generally used and formulated as sanitizing compositions to combat microbial growth according to a specific application.

[008] The effectiveness of biocidal disinfectant compositions in the United

States is determined by the OECD Quantitative Test Method for Evaluating Microbiocides on Surfaces. To claim an efficacious biocidal composition, a 4 log to a 5 log reduction after 10 minutes contact kill time is needed against a number of specific target organisms such as Pseudomonas aeruginosa (Pseudomonas), Staphylococcus aureus (Staphylococcus), Salmonella enterica (Salmonella), etc. Similarly, European Standard Test EN 13697, which is a quantitative non-porous surface standard method, requires a composition to demonstrate a minimum of a 4 log reduction after 10 minutes contact time against a number of target organisms found in various industries for the composition to be considered efficacious.

[009] Unfortunately, many antimicrobial compositions, including

compositions containing peroxyacids, only pass the above test when the

compositions are in a concentrated form.

[0010] In view of the above, a need remains for an antimicrobial composition that is efficacious in diluted form while also being safe to use. More particularly, a need exists for an antimicrobial composition that is well suited to activating and stabilizing a peroxide, such as hydrogen peroxide. A need also exists for an antimicrobial composition that may be used in a highly diluted state that is effective against a broad range of microorganisms and can serve as a biocide even when contact times are very short.

SUMMARY

[0011] The present disclosure is generally directed to an antimicrobial composition that is effective against a broad range of microorganisms. In addition, the antimicrobial composition can display excellent kill rates even during short contact times, such as less than 5 minutes. Not only is the antimicrobial composition of the present disclosure safe and non-hazardous, but the

composition is also efficacious against a broad range of microorganisms even when diluted to very low concentrations. For example, as will be described in greater detail below, the compositions of the present disclosure are well suited to activating and stabilizing a peroxide, such as hydrogen peroxide.

[0012] In general, the antimicrobial composition of the present disclosure contains a peroxide, such as hydrogen peroxide or a hydrogen peroxide producing compound, and/or an organic peroxyacid in combination with a peroxytungstic acid. The peroxytungstic acid can be a monoperoxytungstic acid, a

diperoxytungstic acid, or mixtures thereof. It was discovered that the addition of a peroxytungstic acid dramatically improves the efficacy of a peroxide to act as a biocide, to destroy microorganisms, and/or to prevent the growth of

microorganisms, such as bacteria and algae.

[0013] The antimicrobial composition generally comprises a liquid medium having a pH of less than about 8. The composition can contain a liquid carrier, which can also act as a solubilizer for at least one component contained in the composition. The liquid carrier can comprise, for instance, water, an alcohol, or a mixture of both. In one embodiment, the liquid carrier can contain a surfactant and other liquid components.

[0014] The antimicrobial composition, in one embodiment, can be

formulated as a concentrate and then later diluted and applied to a surface or object for serving as a biocide, a disinfectant, and/or a sanitizing agent. For instance, in one embodiment, during use, the antimicrobial composition may have a total peroxide concentration of generally less than about 2000 ppm, such as less than about 1500 ppm, such as less than about 1000 ppm, such as less than about 800 ppm, such as less than about 500 ppm, such as even less than about 200 ppm. In general, the total peroxide concentration during use is greater than about 50 ppm, such as greater than about 100 ppm. Even at these diluted levels, the antimicrobial composition is efficacious against numerous microorganisms. For instance, when the antimicrobial composition contains water in a sufficient amount such that the total peroxide concentration is 500 ppm, the composition can achieve greater than a 5 log reduction against various microorganisms, such as

Staphylococcus aureus and Pseudomonas aeruginosa after a contact time of 5 minutes (when tested at room temperature, i.e. 23°C). When the total peroxide is contained in the solution in an amount of 1000 ppm, dramatic biocide activity can be observed. For instance, at a total peroxide concentration of 1000 ppm, the composition is capable of achieving a 5 log reduction against Staphylococcus aureus and Pseudomonas aeruginosa even at contact times of one minute or less.

[0015] As used herein, the total peroxide concentration refers to the total concentration of hydrogen peroxide and all peroxyacids (including organic peroxyacids and peroxytungstic acids) present in the composition. As used herein, an "activated peroxide" concentration refers to the total concentration of

peroxyacids present in the composition. In accordance with the present

disclosure, tungstic acid is incorporated into the composition for activating the hydrogen peroxide. Tungstic acid causes the formation of peroxytungstic acid. It is believed that the presence of the peroxytungstic acid then activates the formation of other peroxyacids, thus enhancing the generation of peroxyacids and the efficacy of the composition. [0016] In one embodiment, the composition can contain one or more peroxyacids and/or the organic acid precursor to the peroxyacid in addition to hydrogen peroxide. In one embodiment, for instance, the composition may comprise: from about 0.2% to about 20% by weight, such as about 1 % to about 15% by weight of hydrogen peroxide; from about 0.01 % to about 3% by weight, such as from about 0.1 % to about 2% by weight of a peroxytungstic acid; from about 0.01 % to about 50% by weight, such as from about 5% to about 30% by weight of a peroxyacid; from about 0.01 % to about 2% by weight of a stabilizer; and from about 0.1 % to about 80% by weight of a liquid carrier, which can be a solubilizer and/or a solvent.

[0017] In one particular embodiment, the antimicrobial composition contains octanoic acid, peroxyoctanoic acid, tungstic acid, peroxytungstic acid, and hydrogen peroxide.

[0018] Other features and aspects of the present disclosure are discussed in greater detail below.

DETAILED DESCRIPTION

[0019] It is to be understood by one of ordinary skill in the art that the present discussion is a description of exemplary embodiments only, and is not intended as limiting the broader aspects of the present disclosure.

[0020] In general, the present disclosure is directed to an antimicrobial composition that contains a hydrogen peroxide source and/or an organic peroxyacid in combination with a peroxytungstic acid. The presence of the peroxytungstic acid dramatically improves the antimicrobial properties of the composition, especially when compared to a composition only containing hydrogen peroxide or a composition containing hydrogen peroxide and other peroxyacids. It is believed that peroxytungstic acid, even when present in very small quantities, can oxidize many organic molecules more efficiently than many peroxides or other peroxyacids. It was discovered that the combination of a hydrogen peroxide source with a peroxytungstic acid significantly enhances antimicrobial activity against a broad range of microorganisms. It was also discovered that the composition is capable of destroying microorganisms even when contact times are relatively short, such as less than three minutes, or even less than one minute. [0021] It is believed that tungstic acid activates hydrogen peroxide to form peroxytungstic acid. Peroxytungstic acid is not only well suited for providing antimicrobial properties, but is also believed to enhance the generation of other peroxyacids, especially when the composition contains organic acids.

[0022] The antimicrobial composition of the present disclosure can be used in numerous and diverse applications. In one embodiment, for instance, the antimicrobial composition may be used to sanitize or disinfect hard, non-porous surfaces. For example, the antimicrobial composition is well suited for disinfecting or sanitizing flooring materials, countertops, ceramic surfaces, metal surfaces, glass surfaces, stone surfaces, and the like. The antimicrobial composition can be used to clean the surfaces, destroy microorganisms on the surface and/or prevent growth of microorganisms on the surface. The antimicrobial composition can be used in numerous different fields. For instance, the antimicrobial composition can be used in the food service industry to disinfect and sanitize food processing equipment and other food processing surfaces or to wash produce, such as vegetables. The antimicrobial composition can also be used in the healthcare industry to disinfect surfaces and/or disinfect utensils. The antimicrobial composition can also be sold for consumer household use. The composition can be used in a concentrated or diluted form depending upon the application. When used as a disinfectant, the composition can generally have a pH of less than about 8, such as in the range of from about 2 to about 7, such as from about 2.5 to about 6, such as from about 3 to about 6. The pH may be higher when diluted.

[0023] In another embodiment, the antimicrobial composition of the present disclosure may be used for algae control in small or large bodies of water. For instance, the composition can be used to control algae in ponds, pools, public fountains, and on marine vessels and marine equipment.

[0024] As described above, the antimicrobial composition of the present disclosure is efficacious against a wide variety of microorganisms, including bacteria and algae. For example, when diluted with water to produce a total peroxide concentration of only 500 ppm, the composition can produce a greater than 5 log reduction within 5 minutes of contact time against both Pseudomonas aeruginosa and Staphylococcus aureus. Unexpectedly and dramatically, a diluted level of 1000 ppm of hydrogen peroxide can achieve greater than a 5 Log reduction within less than one minute of contact time against a number of target organisms such as Pseudomonas aeruginosa and Staphylococcus aureus.

[0025] The antimicrobial composition generally contains a peroxide source and a peroxytungstic acid. The peroxide source may comprise hydrogen peroxide. In other embodiments, however, the peroxide source may comprise a compound that produces hydrogen peroxide. Hydrogen peroxide sources can include, for instance, solutions of alkali-metal hydrogen peroxides, alkali salts of percarbonate and persulfate, and organic peroxides. Organic peroxides can include dicumyl peroxide, dialkyi peroxides, urea peroxides, and the like. Hydrogen peroxide itself can provide numerous advantages and benefits. Hydrogen peroxide not only has activity against a broad range of microorganisms but is also relatively safe to use. Hydrogen peroxide can oxidize and/or bleach a surface, while degrading into very safe byproducts, namely oxygen and water.

[0026] The amount of hydrogen peroxide contained in the composition can depend on numerous factors including the ultimate end use application. Hydrogen peroxide can be added to the composition in order to generate one or more peroxyacids. In general, hydrogen peroxide can be added in excess such that it remains in the composition after a reaction equilibrium has been reached with respect to the other components. In one particular embodiment, when producing a concentrate of the antimicrobial composition, hydrogen peroxide can be present in an amount from about 0.2% to about 20% by weight, such as from about 0.5% to about 15% by weight, such as from about 1 % to about 10% by weight.

[0027] In accordance with the present disclosure, the antimicrobial composition also contains peroxytungstic acid. The peroxytungstic acid has been found to dramatically improve and enhance the antimicrobial activity of the peroxide solution. As used herein, peroxytungstic acid and tungstic acid also include their hydrated forms. Peroxytungstic acid can be produced via the dissolution of tungsten and hydrogen peroxide. Tungsten can be provided in different forms. In one embodiment, peroxytungstic acid can be synthesized by reacting tungstic acid with hydrogen peroxide. The tungstic acid, in one

embodiment, may comprise a hydrate, such as a monohydrate or a dihydrate of tungstic acid. When reacted with hydrogen peroxide, a peroxytungstic acid forms that can comprise a monoperoxytungstic acid, a diperoxytungstic acid, mixtures thereof, and the like.

[0028] In one embodiment, salts of a peroxytungstic acid may be added to the composition alone or in combination with a peroxytungstic acid. For instance, one or more metal salts of a peroxytungstic acid may be included in the

composition. In general, salts of peroxytungstic acids may be included in the composition as long as the pH remains relatively low, such as less than 8, such as less than 7.

[0029] Only relatively minor amounts of peroxytungstic acid present in the antimicrobial composition can unexpectedly and dramatically increase the effectiveness of the composition at destroying microorganisms. In general, the weight ratio of hydrogen peroxide to peroxytungstic acid in the composition can be from about 1 : 15 to about 2,000:1 , such as from about 1 : 10 to about 1 ,000:1 , such as from about 1 :5 to about 500:1 , such as from about 1 :2 to about 150:1 . When producing a concentrated antimicrobial composition, in one embodiment, the peroxytungstic acid may be present in the composition in an amount from about 0.01 % to about 3% by weight, such as from about 0.1 % to about 2% by weight, such as from about 0.2% to about 1 .5% by weight.

[0030] In one embodiment, tungstic acid may be combined with hydrogen peroxide to produce the peroxytungstic acid. Depending upon the amount of tungstic acid added, in one embodiment, tungstic acid may be present in the final composition.

[0031] The antimicrobial composition may also contain a liquid carrier. The liquid carrier can be a solubilizer for one of the components in the composition. The liquid carrier may comprise water, an alcohol, or mixtures thereof. Alcoholic solvents that may be used include ethanol, propanol, isopropanol, n-butanol, benzyl alcohol, ethylene glycol, propylene glycol, butylene glycol, or mixtures thereof and the like. The amount of liquid carrier present in the composition can be adjusted in order to adjust the hydrogen peroxide levels in the composition. When producing a concentrated form of the composition, the liquid carrier may be present in an amount from about 0.1 % to about 80% by weight, such as from about 5% to about 50% by weight. [0032] In one embodiment, the antimicrobial composition can further contain one or more peroxyacids in addition to the peroxytungstic acid. For instance, the composition may contain a Ci to Ci₈ peroxyacid that may be linear, branched, cyclic, or aromatic. The peroxyacid may be derived from mono- and dicarboxylic acids and hydroxyacids, alkylbenzoic and phthalic acids, terephthalic acid, isophthalic acid, or mixtures thereof.

[0033] The one or more peroxyacids contained in the composition can be produced from an organic acid, such as by reacting an organic acid with hydrogen peroxide. The organic peroxyacid can be produced in situ within the composition or can be added to the composition as a peroxyacid. When formed in situ, the composition may also contain the organic acid precursor.

[0034] Various different organic acids may be used to produce peroxyacids. In one embodiment, suitable Ci to Cis carboxylic fatty acids can be reacted with hydrogen peroxide to form peroxyfatty acids including formic, acetic, propionic, butyric, pentanonic, hexanoic, enanthic, caprylic, perlargonic, capric, undecanoic, lauric, tridecanoic, myristic, palmitic, and stearic acid. These acids can be derived from both natural and synthetic sources including fully hydrogenated animal and vegetable fats or oils, or from the oxidation of petroleum wax. The above carboxylic fatty acids, for instance, can be used to produce the following

corresponding peroxyacids for use in the composition: peroxyformic acid, peroxyacetic acid, peroxypropionic acid, peroxybutyric acid, peroxypentanonic acid, peroxyhexanoic acid, peroxyenanthic acid, peroxycaprylic acid,

peroxyperlargonic acid, peroxycapric acid, peroxyundecanoic acid, peroxylauric acid, peroxytridecanoic acid, peroxymyristic acid, peroxypalmitic acid, and peroxystearic acid.

[0035] Some preferred peroxyacids are Ci to Cs peroxyacids, saturated, linear, branched, mono-, di-peroxyacids and peroxyhydroxyacids, or mixtures thereof.

[0036] Particularly preferred organic acids for use in the composition are saturated, linear aliphatic fatty acids with low to medium molecular weight. The more preferred organic acid moieties for use in the present disclosure are monocarboxylic acids and dicarboxylic, hydroxyl- hydrocarbon aliphatic and aromatic moieties having 4 to 12 carbon atoms in a molecule selected from group of butyric acid, caprylic acid, capryic acid, lauric acid, hexanoic acid, octanoic acid, oxalic acid, glutaric acid, malonic acid, malic acid, tartaric acid, succinic acid, lactic acid, glycolic acid, phthalic acid, benzoic acid, hydroxybenzoic acid, paraphthalic acid, metaphthalic acid, adipic acid, sebacic acid, and mixtures thereof. The above organic acids can serve as precursors for forming peroxyacids such as peroxybutyric acid, peroxycaprylic acid, peroxycapryic acid, peroxylauric acid, peroxyhexanoic acid, peroxyoctanoic acid, peroxyoxalic acid, peroxyglutaric acid, peroxymalonic acid, peroxymalic acid, peroxytartaric acid, peroxysuccinic acid, peroxylactic acid, peroxyglycolic acid, peroxyphthalic acid, peroxybenzoic acid, peroxyhydroxybenzoic acid, peroxyparaphthalic acid, peroxymetaphthalic acid, peroxyadipic acid and peroxysebacic acid.

[0037] These acids can react with hydrogen peroxide to form the peroxyacid form suitable for use in the composition of the invention. The peroxyacid in the concentrate are monoperoxyacid, di-peroxyacid, and aromatic peroxyacids, or mixtures thereof.

[0038] In one embodiment, the antimicrobial composition is produced by combining a peroxide source, such as hydrogen peroxide, with one or more organic acids and tungstic acid. The mixture can produce peroxytungstic acid and at least one peroxyorganic acid. The peroxyorganic acid and the peroxytungstic acid are the activated hydrogen peroxide and increase its efficacy.

[0039] When the peroxyacids are formed in the composition, the

composition may further contain water soluble organic acids. The organic acid can comprise any of the organic acids described above. For instance, the organic acids can be selected from a group of Ci to C₆ carboxylic acids including formic acid, acetic acid, propionic acid, oxalic acid, lactic acid, glycolic acid, and succinic acid, and mixtures thereof.

[0040] When contained in the antimicrobial composition, one or more peroxyacids can be present at various ratios in relation to a peroxide source. For instance, the ratio of hydrogen peroxide to one or more peroxyacids can be from about 1 :250 to about 2,000:1 , such as from about 1 :150 to about 1 ,000:1 , such as from about 1 :100 to about 50:1 , such as from about 1 :40 to about 7.5:1 . The total amount of peroxyacids (excluding peroxytungstic acid) contained in the

antimicrobial composition can vary. When producing a concentrated composition, for instance, in one embodiment, the peroxyacid can be present in an amount from about 0.01 % to about 50% by weight, such as from about 2% to about 40% by weight, such as from about 5% to about 30% by weight.

[0041] The ratio of one or more organic peroxyacids to one or more peroxytungstic acids present in the composition can be from about 10:1 to about 250:1 , such as from about 5:1 to about 200:1 , such as from about 5:1 to about 150:1 by weight.

[0042] As described above, the antimicrobial composition can be solvent based by containing water or an alcohol. The solubility and compatibility of the water based concentrate can be further improved by adding suitable amounts of other solubilizers, such as a hydrotrope, surfactants, or mixtures thereof, to improve the solubility and physical properties of the solution.

[0043] The solubilizer can be added to the concentrate to solubilize Ce to Ci8 organic acids and their corresponding peroxyacids. The solubilizer in the concentrate can be any suitable peroxyacid compatible solvent, surfactant, hydrotrope coupling agent, or mixtures thereof.

[0044] Examples of hydrotrope agents include n-octanesulfonate, a xylene sulfonate, a naphthalene sulfonate, or mixtures thereof. Suitable surfactants may be selected from the group of ionic, nonionic and amphoteric surfactants, and preferably nonionic and/or ionic surfactants or mixtures thereof. Compatible nonionic surfactants include alkoxylated alcohols such as ethoxylated alcohols, alkoxylated glycols such as alkoxylated ethylene glycol or propylene glycol with a C6 to Ci 8 alkyl group, alkylated glycols, or mixtures thereof. Ionic surfactants that may be used include alkyl sulfate, alkylethersulfate, and their alkylsulfonic acid, alkylether sulfonic acid, alkylbenzenesulfate, and their corresponding sulfonic acid. Other surfactants that may be used include a quaternary ammonium salt, or a tertiary amine N-oxide. Each of the above mentioned surfactants may be used alone or in combination with other surfactants.

[0045] When present, one or more hydrotropes may be included in the antimicrobial composition in an amount from about 0.1 % to about 20% by weight, such as from about 0.2% to about 10% by weight, when producing a concentrated composition. One or more surfactants may be present in the composition in an amount from about 0.005% to about 20% by weight, such as from about 0.2% to about 10% by weight.

[0046] In one embodiment, the antimicrobial composition of the present disclosure may further comprise a stabilizer. The stabilizer may be added to prevent the components from decomposing prematurely during storage of the concentrate and/or prior to contact with a surface or microorganism. The stabilizer may be for stabilizing the hydrogen peroxide, the peroxyacid, the peroxytungstic acid, or for stabilizing all three components. Examples of suitable stabilizers include acids containing phosphorus, polycarboxylic acids, and phosphates. In one embodiment, the stabilizer may comprise phosphoric acid, or a derivative of phosphoric acid. The stabilizer may also comprise a metal chelator. Examples of stabilizers include phosphoric acid, 1 -hydroxyethylidenediphosphonic acid

(HEDP), phytic acid, aminophosphate, phosphonate and sodium glutamate, NaH₂PO₄, Na tripolyphosphate, organophosphonic acid, amino-phosphonate, silver dihydrogen citrate, diphosphonic acid, ethylenediaminetetraacetic acid (EDTA), N-(hydroxyethyl)-ethylenediaminetriacetic acid (HEDTA), tri(methylene phosphoric acid), diethylenetriamine-penta(methylene phosphoric acid), 2-hydroxy ethylimino bis(ethylene phosphoric acid), citric acid, nitriotriacetic acid (NTA), 2- hydroxyethylimino-diacetic acid (HEIDA), and salts thereof, cyclohexane-1 ,2- diaminotetrakismethylene phosphonic acid or water-sol, diethylenetriamine penta(methylene phosphonic acid), colloidal stannate, diethylenetriamine pentaacetic acid(DTPA), citrate, gallate, malate, malonate, oxaloacetate, oxalate, pyruvate, and succinate or mixtures thereof.

[0047] The stabilizer can be a single component or a mixture of the derivatives of phosphoric acid and chelators described above. The amount of the stabilizer in the concentrate can be from about 0.01 % to about 10%, preferably from about 0.05% to about 5%, and more preferably from about 0.1 % to about 1 .0% by weight.

[0048] Other additives may be also added to the antimicrobial composition of the present disclosure to provide the composition with suitable properties for end use applications. Typical examples include corrosion inhibitors, emulsifiers, fragrances, dyes, preservatives, antifoam agents and mixtures thereof. [0049] In one embodiment, for instance, the antimicrobial composition may contain a corrosion inhibitor. Corrosion inhibitors that may be used include borates, phosphates, polyphosphates, sodium benzoate, sodium gluconate, sodium silicate, sodium molybdate, sodium bisulfate, benzotriazole or mixtures thereof. When present, the corrosion inhibitor can be contained in the composition in an amount from about 0.001 % to about 10% by weight, such as from about 0.01 % to about 1 % by weight.

[0050] In order to produce an antimicrobial composition in accordance with the present disclosure, the different ingredients can be added together to form an aqueous medium. As described above, in one embodiment, the peroxytungstic acid and, if present, one or more peroxyacids can be produced in situ by

combining tungstic acid and the appropriate organic acid with an aqueous hydrogen peroxide solution. A stabilizer can be added into the mixture or added after the concentrate is made.

[0051] A liquid carrier, solvent and/or solubilizer can be added to the antimicrobial composition in order to arrive at the desired concentration and/or to dissolve some of the components. When adding organic acids that are not water soluble to the composition, a non-aqueous solvent or solubilizer may be needed. For instance, higher molecular weight fatty acids are somewhat water insoluble but are soluble in alcohols. When a solvent or solubilizer is needed, it can be added in an amount from about 0.01 % to about 40% by weight.

[0052] In one embodiment, a relatively concentrated antimicrobial composition is produced and sold or otherwise distributed to end users. An end user can then dilute the concentrated solution during or prior to use. Of particular advantage, the antimicrobial composition can be diluted with water, such as tap water.

[0053] In one embodiment, a relatively concentrated antimicrobial composition is produced that contains hydrogen peroxide in an amount from about 0.2% to about 20% by weight, such as from about 1 % to about 15% by weight, one or more peroxyacids in an amount from about 0.01 % to about 50% by weight, such as from about 5% to about 30% by weight, a peroxytungstic acid present in an amount from about 0.01 % to about 3% by weight, such as from about 0.1 % to about 2% by weight, and a stabilizer in an amount from about 0.01 % to about 2% by weight. One or more liquid carriers (which may also serve as a solubilizer) may generally be present in an amount from about 0.1 % to about 80% by weight.

[0054] In general, the antimicrobial composition has a neutral to acidic pH. The pH of the composition, for instance, can be from about 2 to about 7, such as from about 2.5 to about 6, such as from about 3 to about 6.

[0055] If desired, various other antimicrobial agents can be added to the composition to further increase the scope of activity. In one embodiment, for instance, one or more quaternary ammonium salts may be added to the

composition. When present, the quaternary ammonium salts can be present in an amount from about 0.1 % to about 30% by weight, such as from about 1 % to about 20% by weight.

[0056] When used to sanitize or disinfect a surface or object or when used to bleach an article, the concentration of the various components can be varied in order to achieve a desired result. In one embodiment, when used as a

disinfectant, the antimicrobial composition may be diluted such that the hydrogen peroxide concentration can be from about 1 ppm to about 5,000 ppm, such as from about 10 ppm to about 1 ,000 ppm, such as from about 50 ppm to about 500 ppm. Total peroxide concentration in the solution during use can generally be from about 1 ppm to about 10,000 ppm, such as from about 10 ppm to about 5,000 ppm, such as from about 10 ppm to about 2000 ppm, such as from about 10 ppm to about 500 ppm.

[0057] The total activated peroxide composition can be from about 1 ppm to about 5,000 ppm, such as from about 10 ppm to about 1 ,000 ppm, such as from about 10 ppm to about 500 ppm, such as from about 10 ppm to about 200 ppm, such as from about 10 ppm to about 100 ppm.

[0058] The antimicrobial composition may be used in any suitable

application where disinfecting, sanitizing, cleaning and/or bleaching are desired. The antimicrobial composition can be used for consumer household use, for use in the healthcare field, for use in the food processing field or food service field, for use in sterilizing surfaces in dairies and breweries, for use in the veterinarian field, and/or for use in clean rooms. The antimicrobial composition is also well suited for disinfecting bodies of water by controlling algae growth and/or other microbes in the bodies of water, such as ponds, pools, fountains, toilet bowls and aquariums. The present disclosure may be better understood with reference to the following examples.

Example No. 1

[0059] The following examples demonstrate some of the advantages and benefits of the present disclosure.

[0060] Table 1 below lists four precursor compositions made in accordance with the present disclosure. After the components were mixed, the tungstic acid reacted with the hydrogen peroxide to form peroxytungstic acid. The organic acids also reacted with peroxytungstic acid and hydrogen peroxide to form peroxyacids. After the compositions were formulated and mixed, the resulting compositions contained unreacted hydrogen peroxide, activated peroxyacid, peroxytungstic acid, unreacted organic acid, unreacted tungstic acid, and the other listed components.

[0061] Experiments were conducted to determine the antimicrobial efficacy of the compositions produced from each example shown in Table I according to the OECD quantitative method for evaluating bacterial activity of biocides used on hard, nonporous surface. The results are tabulated in Table 2.

[0062] The method utilized brushed stainless steel coupons as carriers. Log reduction was the main test variable and the quantitative measure of efficacy. The mean control carrier counts specified in the method fall between 4.5 and 5.5 logs CFU/carrier, assuming a 4 log performance standard. In conjunction with the control count range, default test parameters of 375 ppm hard water as the test substance diluent, a 3-part soil load, and a 5 minute contact time were applied. The test focused on activity against Pseudomonas aeruginosa and

Staphylococcus aureus.

[0063] Peroxyacids, mono-and diperoxytungstic acids contained in the compositions were identified by LC-MS. Use level of total peroxide in the test dilution samples was calculated based on the amount of hydrogen peroxide used to produce the concentrate compositions.

[0064] The results shown in Table 2 demonstrate the antimicrobial efficacy of the compositions at very low levels when exposed to Staphylococcus aureus and Pseudomonas aeruginosa. The compositions listed in Table 2 were tested by diluting the samples with 375 ppm hard water to test the level of total peroxide calculated based on the amount of hydrogen peroxide used to produce the compositions.

[0065] It is believed that the test level of activated hydrogen peroxide shown in Table 2 is equivalent to the total peroxide level of combined peroxyacid and peroxytungstic acid present in the composition. Thus, the actual level of peroxyacid in the test dilution sample should be much lower than the test level of hydrogen peroxide shown in the table.

Table 1 Test samples

¹ wt% of the unreacted hydrogen peroxide leftover in the concentrate; ² wt% of the hydrogen peroxide used to produce peroxyacid(s) in the concentrate.

Table 2 OECD quantitative test results

(All OECD tests were done by diluting the concentrate with 375 ppm hard water)

¹ pH of the diluted use solution was between 3 and 4; total activated hydrogen peroxide including peroxyacids and peroxytungstic acid; ³ The test was conducted with one minute contact time.

[0066] The results demonstrate that both hydrogen peroxide and octanoic acid are ineffective alone as an antimicrobial agent to achieve >5 Log reduction of microorganisms tested. For example, a solution containing 3,000 ppm of hydrogen peroxide achieved only 1 .0 and 0.5 log reduction with 5 minutes of contact time against Staphylococcus aureus and Pseudomonas aeruginosa. A 2000 ppm octanoic acid solution has no appreciable antimicrobial activity.

[0067] In sharp contrast, the solutions of the present disclosure having a total peroxide concentration between 250 to 500 ppm based on the amount of hydrogen peroxide used for producing the concentrate composition (Sample Nos. 1 , 2, 3, 4 and 5), or >100 ppm activated hydrogen peroxide in the use solution (Sample No. 4), and having a pH in the range of about 3 to 4 achieved a greater than 5 log reduction within 5 minutes of contact time against a number of specific target Pseudomonas aeruginosa (Pseudomonas) and Staphylococcus aureus (Staphylococcus).

[0068] The result shown in Sample No. 5 demonstrates that a diluted level of about 1000 ppm of hydrogen peroxide or less than 200 ppm activated hydrogen peroxide can achieve greater than 5 Log reduction in hard water within less than one minute of contact time against a number of target organisms such as

Pseudomonas aeruginosa and Staphylococcus aureus.

[0069] Additionally, the above diluted compositions are also very effective against three fresh water algae, Chlorella pyrenoidosa, Raphidocelis subcapitata and Microcystis aeruqinosa. As shown in Table 3, the compositions showed good efficacies with respect to the conventional Minimum Inhibitory Concentration (MIC) values. The compositions displayed less than 7.8 ppm against Chlorella pyrenoidosa and Raphidocelis subcapitata and 1 .0 - 2.0 ppm against Microcystis aeruginosa. The MIC values are based on the amount of hydrogen peroxide used for producing the initial compositions.

Table 3 MIC values of the compositions against algae (ppm based on hydrogen peroxide used for making the concentrate)

*Sample No. 6: The initial composition: Sample No. 5: 9.66% octanoic acid, 10.9% hydrogen peroxide, 0.58% tungstic acid, 0.25% phosphoric acid, 10.98% water and 67.6% propanol.

Example No. 2

[0070] The procedures described in Example No. 1 were repeated for the following compositions, which produced the following results when tested according to the OECD Quantitative Method. Table 4 AHP compositions and OECD test results

[0071] The result shown in Sample No. 7 demonstrates that a diluted level of about 470 ppm activated hydrogen peroxide can achieve greater than 5 Log reduction in hard water within about 30 seconds of contact time against a number of target organisms such as Pseudomonas aeruginosa and Staphylococcus aureus.

[0072] These and other modifications and variations to the present invention may be practiced by those of ordinary skill in the art, without departing from the spirit and scope of the present invention, which is more particularly set forth in the appended claims. In addition, it should be understood that aspects of the various embodiments may be interchanged both in whole or in part. Furthermore, those of ordinary skill in the art will appreciate that the foregoing description is by way of example only, and is not intended to limit the invention so further described in such appended claims.

Claims

What Is Claimed:

1 . An antimicrobial composition comprising a hydrogen peroxide source, an organic peroxyacid or mixtures thereof in combination with a

peroxytungstic acid, and wherein the composition comprises a liquid medium having a pH of less than about 8.

2. An antimicrobial composition as defined in claim 1 , wherein the composition contains the organic peroxyacid, the organic peroxyacid comprising a Ci to Ci8 peroxyacid.

3. An antimicrobial composition as defined in claim 2, wherein the peroxide is present in combination with the peroxyacid in a weight ratio of from about 1 :250 to about 2,000:1 , such as from about 1 :150 to about 1 ,000:1 , such as from about 1 :100 to about 50:1 , such as from about 1 :40 to about 7.5:1 .

4. An antimicrobial composition according to any of the preceding claims, wherein the peroxide is present in combination with the peroxytungstic acid in a weight ratio of from about 1 : 15 to about 2,000:1 , such as from about 1 : 10 to about 1 ,000:1 , such as from about 1 :5 to about 500:1 , such as from about 1 :2 to about 150:1 .

5. An antimicrobial composition as defined in any of the preceding claims, further comprising an organic acid.

6. An antimicrobial composition as defined in any of the preceding claims, wherein the hydrogen peroxide source comprises hydrogen peroxide, sodium percarbonate, carbamide peroxide, and mixtures thereof.

7. An antimicrobial composition as defined in claim 2, wherein the peroxyacid and the peroxytungstic acid are present in the composition at a weight ratio of from about 10:1 to about 250:1 .

8. An antimicrobial composition as defined in claim 2, wherein the Ci to Ci8 peroxyacid comprises a peroxycarboxylic acid.

9. An antimicrobial composition as defined in claim 5, wherein the organic acid comprises formic acid, acetic acid, citric acid, propionic acid, butyric acid, pentanoic acid, hexanoic acid, octanoic acid, decanoic acid, lauric acid, adipic acid, lactic acid, glycolic acid, oxalic acid, sebacic acid, glutaric acid, malic acid, malonic acid, succinic acid, tartaric acid, or mixtures thereof.

10. An antimicrobial composition as defined in any of the preceding claims, further containing a peroxide stabilizer.

1 1 . An antimicrobial composition as defined in claim 10, wherein the peroxide stabilizer comprises a phosphoric acid, etidronic acid, a phytic acid, a derivative of a phosphoric acid and a metal chelator, or mixtures thereof.

12. An antimicrobial composition as defined in any of the preceding claims, wherein the liquid medium has a pH of from about 2 to about 7, such as from about 3 to about 6.

13. An antimicrobial composition as defined in claim 1 , further containing a liquid carrier, the liquid carrier comprising water, an alcohol, or mixtures thereof.

14. An antimicrobial composition as defined in any of the preceding claims, further comprising a surfactant.

15. An antimicrobial composition as defined in any of the preceding claims, further comprising a hydrotrope.

16. An antimicrobial composition as defined in claim 14, wherein the surfactant comprises an alkylated glycol, a quaternary ammonium salt, a tertiary amine N-oxide, or mixtures thereof.

17. An antimicrobial composition as defined in claim 15, wherein the hydrotrope comprises n-octanesulfonate, a xylene sulfonate, a naphthalene sulfonate, or mixtures thereof.

18. An antimicrobial composition as defined in any of the preceding claims, further comprising a corrosion inhibitor.

19. An antimicrobial composition as defined in claim 18, wherein the corrosion inhibitor comprises a borate, a phosphate, a polyphosphate, sodium benzoate, sodium gluconate, sodium silicate, sodium molybdate, sodium bisulfate, a benzotriate, or mixtures thereof.

20. An antimicrobial composition as defined in claim 1 , wherein the peroxide comprises hydrogen peroxide, and wherein the composition further contains octanoic acid, peroxyoctanoic acid, and tungstic acid.

21 . An antimicrobial composition as defined in any of the preceding claims, wherein the peroxide comprises hydrogen peroxide and wherein, when the composition contains water such that the total peroxide concentration in the composition is less than 500 ppm, the composition causes greater than a 5 log reduction against Staphylococcus aureus and Pseudomonas aeruginosa after a contact time of 5 minutes.

22. An antimicrobial composition as defined in any of the preceding claims, wherein the peroxide comprises hydrogen peroxide and wherein when the composition contains water such that the total peroxide concentration in the composition is less than1000 ppm, the composition causes greater than a 5 log reduction against Staphylococcus Aureus and Pseudomonas Aeruginosa after a contact time of 1 minute.

23. The use of an antimicrobial composition as defined in any of the preceding claims for disinfecting hard surfaces.

24. The use of an antimicrobial composition as defined in any of the preceding claims for controlling algae growth.

25. The use of an antimicrobial composition as defined in any of the preceding claims for cleaning vegetables.

26. An antimicrobial composition as defined in any of the preceding claims, wherein the peroxide comprises hydrogen peroxide and is present in the composition in an amount from about 0.2% to about 20% by weight, such as from about 1 % to about 15% by weight, the composition containing a peroxyacid in an amount from about 0.01 % to about 50% by weight, such as from about 5% to about 30% by weight, the peroxytungstic acid being present in an amount from about 0.01 % to about 3% by weight, such as from about 0.1 % to about 2% by weight, such as from about 0.2% to about 1 .5% by weight, the composition further comprising a stabilizer in an amount from about 0.01 % to about 2% by weight and a liquid carrier, the liquid carrier being present in an amount from about 0.1 % to about 80% by weight.

27. An antimicrobial composition as defined in any one of claims 1 -25, wherein the composition has a total peroxide concentration of less than about 1000 ppm, such as less than about 500 ppm and has a total peroxide

concentration of greater than about 1 ppm, such as greater than about 10 ppm.

28. An antimicrobial composition as defined in any of the preceding claims, wherein the peroxytungstic acid comprises a monoperoxytungstic acid.

29. An antimicrobial composition as defined in any of the preceding claims, wherein the peroxytungstic acid comprises a diperoxytungstic acid.

30. A method for disinfecting a hard surface comprising:

contacting a surface with an antimicrobial composition as defined in any of the preceding claims.

31 . A method as defined in claim 30, wherein the hard surface comprises food processing equipment or a food preparation surface.

32. A method as defined in claim 30, wherein the hard surface comprises a surface used in the healthcare industry or in the veterinarian industry.

33. A method for disinfecting a body of water comprising

adding the antimicrobial composition as defined in any one of the preceding claims to the body of water.