Self-stabilized disinfectant composition

Abstract

An antimicrobial composition is disclosed containing relatively high amounts of a self-stabilized hydrogen peroxide. The hydrogen peroxide is combined with a stabilizer package including an organic sulfonic acid or salt thereof and relatively low amounts of a carboxylic acid. The composition is not only stable but also very effective against all different types of microorganisms.

Description

SELF-STABILIZED DISINFECTANT COMPOSITIONCROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to the benefit of U.S. Provisional Application No. 63 / 514,617, filed July 20, 2023, and to the benefit of U.S. Provisional Application No. 63 / 648,694, filed May 17, 2024 which are expressly incorporated herein by reference in their entireties.BACKGROUND

[0002] 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 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.

[0003] 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.

[0004] Unfortunately, hydrogen peroxide as an oxidizer is typically not stable in most formulations. For instance, many hydrogen peroxide-based disinfectant products have a shelf life of less than one year. Consequently, hydrogen peroxide is typically combined with one or more stabilizers and / or converted into peracetic acid in formulating disinfectant products. Examples of common stabilizers for hydrogen peroxide include phosphoric acid, 1-hydroxyethylidene- 1 ,1-diphosphonic acid (HEDP), picolinic acid, dipicolinic acid, ethylenediamine- N,N'-disuccinic acid, and the like. These stabilizers, however, can significantly increase the cost of the product. Various stabilizers, for instance, are disclosed in U.S. Patent No. 9,321 ,664, which is incorporated herein by reference.

[0005] In other embodiments, hydrogen peroxide has been combined with copious amounts of acetic acid in order to produce peracetic acid in situ. For instance, U.S. Patent Publication No. 2015 / 0291520, which is incorporated herein by reference, discloses a method for producing peracetic acid by reacting acetic acid with hydrogen peroxide. Acetic acid and peracetic acid, however, can produce an unpleasant odor. In addition, peracetic acid can cause skin irritation and is not as environmentally friendly as hydrogen peroxide.

[0006] In view of the above, a need currently exists for an antimicrobial composition that contains a stable hydrogen peroxide without having an unpleasant odor. A need also exists for a hydrogen peroxide-based antimicrobial composition that does not require the use of stabilizers and / or a composition where a substantial portion of the hydrogen peroxide is not converted to peracetic acid.SUMMARY

[0007] The present disclosure is generally directed to an antimicrobial composition that is effective against a broad range of microorganisms. For example, one particular microorganism that is difficult to control is Clostridium difficile. C. difficile is a pathogen that is capable of causing severe gastrointestinal disease in mammals, especially humans. In fact, C.difficile is the leading cause of hospital-acquired diarrhea and is the primary cause of pseudomembranous colitis. The number of cases of C.difficile associated diseases has continued to increase annually. For instance, patients that are on antibiotics or undergoing chemotherapy are particularly susceptible to acquiring a C.difficile associated disease. As the frequency of disease has increased, hospitals have become even more contaminated with spores of C.difficile making infection of susceptible patients more probable. The antimicrobial composition of the present disclosure, however, is well suited to destroying and inhibiting the growth of C.difficile.

[0008] In addition to being effective against C.difficile, the antimicrobial composition of the present disclosure is safe and non-hazardous. The antimicrobial composition can be formulated to be free of hydrogen peroxide stabilizers. In addition, the antimicrobial composition of the present disclosurecan contain very low amounts of acetic acid that reduces or eliminates the emission of odors.

[0009] In one embodiment, for instance, the present disclosure is directed to an antimicrobial composition comprising an aqueous solution. The aqueous solution contains hydrogen peroxide in relatively great amounts. For instance, hydrogen peroxide can be present in the aqueous solution in an amount greater than about 1 % by weight, such as in an amount greater than about 2% by weight, such as in an amount greater than about 3% by weight, such as in an amount greater than about 4% by weight. The composition also contains an organic sulfonic acid. The composition can also contain a C1-C14 carboxylic acid. The carboxylic acid may be present in the composition in an amount greater than about 0.1 % by weight, such as in an amount greater than about 0.5% by weight, such as in an amount greater than about 0.8% by weight, such as in an amount greater than about 1.2% by weight, such as in an amount greater than about 1 .5% by weight, such as in an amount greater than about 1 .8% by weight. The carboxylic acid may be present in an amount less than about 6% by weight, such as in an amount less than about 4% by weight, such as in an amount less than about 3% by weight. The carboxylic acid, for instance, can be acetic acid. The composition can have a pH of less than about 4 and can display a 6 log reduction or greater after a 10 minute contact time, such as after a 5 minute contact time, such as after a 2 minute contact time when tested against Clostridium difficile according to ASTM Test Method E2197-11.

[0010] As described above, the antimicrobial composition can contain an organic sulfonic acid or salt thereof. The organic sulfonic acid or salt thereof can comprise a C1-C5 alkylsulfonic acid, a sulfonated C1-C5 carboxylic acid, a substituted or unsubstituted aromatic sulfonic acid, a mono-alkylphenylsulfonic acid, a di-alkylphenylsulfonic acid, or salts thereof, or mixtures thereof. In one aspect, the organic sulfonic acid or sat thereof comprises a substituted aromatic or aliphatic sulfonic acid or salt thereof that is substituted with at least one C1-C3 alkyl group or phenyl group. Particular examples of organic sulfonic acids that may be used in accordance with the present disclosure include methane sulfonic acid, benzene sulfonic acid, toluene sulfonic acid, or saltsthereof, or mixtures thereof. The organic sulfonic acid or salt thereof can be present in the composition in an amount from about 0.1 % by weight to about 6% by weight, including all increments of 0.1 % therebetween. For instance, the organic sulfonic acid or salt thereof can be present in the composition in an amount from about 0.2% by weight to about 4% by weight. The hydrogen peroxide can be present in the composition in relation to the organic sulfonic acid or salt thereof at a weight ratio of from about 40: 1 to about 1 :2, such as from about 20: 1 to about 1 :2, such as from about 10:1 to about 1 :1.

[0011] As described above, the antimicrobial composition of the present disclosure can be formulated so as not to contain any hydrogen peroxide stabilizers. For instance, in one aspect, the composition does not contain 1- hydroxyethylidene-1 ,1-diphosphonic acid. In another aspect, the composition can be free of a pyridine carboxylic acid, such as picolinic acid and / or dipicolinic acid.

[0012] The composition can contain various other components. For instance, the composition can contain a nonionic surfactant. In one aspect, the composition can contain an anionic surfactant. For instance, anionic surfactants that may be incorporated into the composition include a linear alkylbenzene sulfonic acid or salt thereof, an alkylsulfate, an alkanolamide sulfate, an ethoxylated alkylphenol, or mixtures thereof. In one embodiment, the anionic surfactant comprises sodium dodecylbenzene sulfonate.

[0013] The composition can also contain a pH adjusting agent. The pH adjusting agent, for instance, may comprise a hydroxide, such as sodium hydroxide, potassium hydroxide, ammonium hydroxide, calcium hydroxide, magnesium hydroxide, or mixtures thereof.

[0014] It was surprisingly discovered that the composition of the present disclosure is self-stabilizing. For instance, in one aspect, after storage at 54°C for one week, the antimicrobial composition can display a hydrogen peroxide loss of less than 2% by weight. Hydrogen peroxide loss is determined according to the following equation:[Initial H2O2 % - H2O2 % (after storage at 54°C)] / lnitial H2O2 % x 100

[0015] In one embodiment, the antimicrobial composition can display a hydrogen peroxide loss of less than 5% by weight, such as less than 3% byweight, such as less than 2% by weight, such as less than about 1 % by weight after storage at 54°C for two weeks.

[0016] The present disclosure is also directed to a method for disinfecting a hard or soft surface. The method includes the step of contacting a surface with an antimicrobial composition as described above. The hard surface can be a surface used in the health care industry or in a veterinarian industry. Alternatively, the hard surface can comprise food processing equipment or a food preparation service.

[0017] The antimicrobial composition of the present disclosure can be applied to surfaces using various different techniques. For instance, the composition can be sprayed or otherwise applied to a surface directly. Alternatively, the antimicrobial composition can be applied to a wiping product which is then used to apply the composition to a surface. In this regard, the present disclosure is also directed to a premoistened wiping product containing the antimicrobial composition as described above.

[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 relatively high concentration of hydrogen peroxide. In one aspect, the composition is formulated so as not to contain any hydrogen peroxide stabilizers. Consequently, the composition can be considered selfstabilized containing relatively high amounts of hydrogen peroxide that has a shelf life of at least one year, such as at least two years. The antimicrobial composition contains a unique combination of hydrogen peroxide, an organic sulfonic acid or salt thereof, and a carboxylic acid, such as acetic acid. In the past, the above acids have been combined with hydrogen peroxide in order toconvert the hydrogen peroxide to peracetic acid. In the present disclosure, however, it was unexpectedly discovered that relatively low amounts of the carboxylic acid in combination with the organic sulfonic acid or salt thereof can produce a hydrogen peroxide composition in which the hydrogen peroxide remains relatively stable. In addition, the unique combination of the organic sulfonic acid or salt thereof in combination with relatively low amounts of the carboxylic acid were discovered to activate the efficacy of the hydrogen peroxide for making the antimicrobial composition very effective against a broad range of microorganisms.

[0021] More particularly, it was discovered that the antimicrobial composition of the present disclosure is particularly well suited to destroying and inhibiting the growth of Clostridium difficile even when contact times are relatively short. For example, the antimicrobial composition of the present disclosure is capable of achieving at least a 6 log reduction against C. difficile when tested according to ASTM Test Methods ASTM E2197-11 and E2839-11 after a 10 minute contact time, after a 5 minute contact time, or even after a 2 minute contact time.

[0022] Because the antimicrobial composition of the present disclosure contains relatively low amounts of a carboxylic acid and contains very low amounts of peracetic acid, the antimicrobial composition of the present disclosure has dramatically lower odor properties compared to many conventional products. For instance, the antimicrobial composition of the present disclosure can be formulated so as to be substantially free of peracetic acid, and / or free of chlorine bleach.

[0023] 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.

[0024] The antimicrobial composition is also well suited to sanitizing soft surfaces. Examples of soft surfaces include, but are not limited to, upholstery, fabric, upholstered couches, sofas, chairs, seat cushions, upholsteredcushions, pillows, upholstered furniture, fabric window treatments, curtains, draperies, shower curtains, fabric gym / laundry diaper bags, backpacks, fabric hampers, fabric dog / pet bedding, blankets, fabric upholstered car seats, fabric stuffed animals, toys, and the like.

[0025] The antimicrobial composition can be used to clean the surfaces, disinfect 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 is well suited for use in the healthcare industry to disinfect surfaces and / or disinfect utensils. The antimicrobial composition can be used in hospitals, for example, in order to prevent the spread of C.difficile. 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 sold for consumer household use. The composition can be used in a concentrated or diluted form depending upon the application.

[0026] The antimicrobial composition generally contains a hydrogen peroxide source in combination with an organic sulfonic acid or a salt thereof, and a carboxylic acid. The hydrogen peroxide source may comprise hydrogen peroxide. In other embodiments, however, the hydrogen 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, dialkyl 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.

[0027] As described above, the antimicrobial composition of the present disclosure not only contains a relatively high concentration of hydrogen peroxide, but also contains the hydrogen peroxide in a relatively stable state. The composition, for instance, can contain hydrogen peroxide in an amountgreater than about 1 % by weight, such as in an amount greater than about 2% by weight, such as in an amount greater than about 3% by weight, such as in an amount greater than about 4% by weight, such as in an amount greater than about 5% by weight, such as in an amount greater than about 6% by weight. The hydrogen peroxide can be present in the composition in an amount less than about 10% by weight, such as in an amount less than about 8% by weight, such as in an amount less than about 6.5% by weight in a ready-to-use composition.

[0028] In accordance with the present disclosure, the antimicrobial composition also contains an organic sulfonic acid or salt thereof in combination with relatively minor amounts of a carboxylic acid. The organic sulfonic acid or salt thereof can be a non-surfactant sulfonic acid. Examples of sulfonic acids or salts thereof that may be used include C1-C7 alkylsulfonic acid, a sulfonated C1- C7 carboxylic acid, a substituted or unsubstituted aromatic sulfonic acid, mixtures thereof and salts thereof. In another embodiment, the alkylsulfonic acid and sulfonated carboxylic acid have a C1-C5 chain. In the case of a substituted aromatic sulfonic acid, the aromatic ring can be substituted with at least one C1-C3 alkyl group. Stated otherwise, if the aromatic ring is substituted, the alkyl group can contain three (3) carbons or less. Salts of the nonsurfactant organic sulfonic acid are alkali metal and alkaline earth metals salts, such as sodium, potassium, calcium and magnesium. Salts may also include ammonium salts. Representative examples of the non-surfactant organic sulfonic acid are methane sulfonic acid, benzene sulfonic acid, toluene sulfonic acid, xylenesulfonic acid, ethylbenzene sulfonic acid, and mixtures thereof.

[0029] The organic sulfonic acid or salt thereof can generally be present in the antimicrobial composition in an amount of from about 0.1 % by weight to about 6% by weight including all increments of 0.1 % by weight therebetween. For example, the organic sulfonic acid or salt thereof can be present in the antimicrobial composition in an amount greater than about 0.5% by weight, such as in an amount greater than about 1 % by weight, such as in an amount greater than about 1 .5% by weight, and generally in an amount less than about 5% by weight, such as in an amount less than about 4% by weight, such as in an amount less than about 3% by weight. In one aspect, the organic sulfonicacid comprises methane sulfonic acid and is present in the composition in an amount from about 1 .5% by weight to about 2.5% by weight, such as in an amount from about 1 .8% by weight to about 2.2% by weight.

[0030] The hydrogen peroxide is combined with the organic sulfonic acid or salt thereof and relatively minor amounts of a carboxylic acid. The relative amounts of the organic sulfonic acid and the carboxylic acid in combination with relatively great amounts of hydrogen peroxide have been found to “selfstabilize” the hydrogen peroxide preventing the hydrogen peroxide from degrading or converting to peracetic acid. The organic sulfonic acid and the carboxylic acid also are believed to activate the efficacy of the hydrogen peroxide for making the antimicrobial composition highly effective against various microorganisms including C.difficile at very short contact times.

[0031] In one aspect, the carboxylic acid can comprise a Ci to C14 carboxylic acid. For instance, the carboxylic acid may comprise a Ci to C4, such as a Ci to C2 carboxylic acid. In one embodiment, the carboxylic acid may comprise formic acid, carbonic acid, and / or acetic acid. As used herein, a carboxylic acid includes carbonic acid in the context of this invention. More particularly, carbonic acid is considered as one of the possible Ci to C2 carboxylic acids.

[0032] The carboxylic acid may be present in the composition in a ready-to use state in an amount greater than about 0.1 % by weight, such as in an amount greater than about 0.5% by weight, such as in an amount greater than about 0.8% by weight, such as in an amount greater than about 1 .2% by weight, such as in an amount greater than about 1.5% by weight, such as in an amount greater than about 1 .8% by weight. The carboxylic acid may be present in the antimicrobial composition in a ready-to-use state in an amount of less than about 6% by weight, such as in an amount less than about 5% by weight, such as in an amount less than about 4% by weight, such as in an amount less than about 3% by weight, such as in an amount less than about 2.5% by weight, such as in an amount less than about 2.2% by weight. The carboxylic acid may be present in the antimicrobial composition in a ready-to-use state in an amount from about 0.5% by weight to about 6% by weight, such as from about 1 % by weight to about 5% by weight, such as from about 1 .5% by weight to 4% by weight, such as from about 2% by weight to 3 % by weight.

[0033] The weight ratio between hydrogen peroxide and the organic sulfonic acid or salt thereof and the weight ratio between hydrogen peroxide and the carboxylic acid can vary depending upon the particular application and the desired result. In one aspect, the weight ratio between hydrogen peroxide and the organic sulfonic acid can be from about 40:1 to about 1 :2, such as from about 12:1 to about 1 :1 , such as from about 10:1 to about 5: 1. The weight ratio between hydrogen peroxide and the carboxylic acid can be from 500:1 to about 2:1 , such as from about 100: 1 to about 2:1 , such as from about 40: 1 to about 2:1 , such as from about 20:1 to about 2:1 , such as from about 12:1 to about 4:1.

[0034] 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. The liquid carrier may be present in an amount from about 20% to about 95% by weight, such as from about 50% to about 80% by weight. For instance, one or more liquid carriers can be present in the antimicrobial composition in an amount greater than about 60% by weight, such as in an amount greater than about 70% by weight, such as in an amount greater than about 75% by weight.

[0035] The solubility and compatibility of the liquid antimicrobial composition 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.

[0036] Examples of hydrotrope agents include n-octanesulfonate, a xylene sulfonate, a naphthalene sulfonate, or mixtures thereof. One or more hydrotropes can be included in the antimicrobial composition generally in an amount less than about 5% by weight, such as in an amount less than about 2% by weight, such as in an amount less than about 1 % by weight. One or more hydrotropes can be present in the composition in an amount greater thanabout 0.01 % by weight, such as in an amount greater than about 0.1 % by weight, such as in an amount greater than about 0.5% by weight.

[0037] 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 Ce to Cis alkyl group, alkylated glycols, or mixtures thereof. When present, the antimicrobial composition may contain one or more nonionic surfactants in an amount greater than about 0.1 % by weight, such as in an amount greater than about 0.5% by weight, such as in an amount greater than about 1 .5% by weight, such as in an amount greater than about 2.5% by weight, such as in an amount greater than about 3% by weight, such as in an amount greater than about 5% by weight, such as in an amount greater than about 7% by weight, such as in an amount greater than about 8% by weight. One or more nonionic surfactants can be present in the composition in an amount less than about 25% by weight, such as in an amount less than about 15% by weight, such as in an amount less than about 10% by weight, such as in an amount less than about 5% by weight. In one aspect, relatively small amounts of nonionic surfactants can be incorporated into the composition such as in an amount less than about 2.5% by weight, such as in an amount less than about 1.5% by weight, such as in an amount less than about 1 % by weight.

[0038] Instead of or in addition to one or more nonionic surfactants, the antimicrobial composition may also contain one or more anionic surfactants. Suitable anionic surfactants include alkyl sulfate, alkylethersulfate, alkylether sulfonic acid and salts thereof, alkylbenzenesulfate, an alkanolamide sulfate, an ethoxylated alkylphenol, or mixtures thereof. Other surfactants that may be used include a quaternary ammonium salt, or a tertiary amine N-oxide. In one embodiment, the antimicrobial composition contains a salt of an alkylbenzene sulfonate, such as sodium dodecylbenzene sulfonate.

[0039] One or more anionic surfactants are generally contained in the antimicrobial composition at relatively minor amounts. For instance, one or more anionic surfactants can be present in the composition in an amount lessthan about 5% by weight, such as in an amount less than about 3% by weight, such as in an amount less than about 1 .5% by weight, such as in an amount less than about 1 % by weight, such as in an amount less than about 0.8% by weight. One or more anionic surfactants can be present in the composition in an amount greater than about 0.001 % by weight, such as in an amount greater than about 0.01 % by weight, such as in an amount greater than about 0.1 % by weight, such as in an amount greater than about 0.3% by weight.

[0040] In the past, antimicrobial compositions containing hydrogen peroxide typically required the use of a stabilizer for the hydrogen peroxide. The composition of the present disclosure, however, was unexpectedly found to self-stabilize the hydrogen peroxide without the need to add any hydrogen peroxide stabilizers. Thus, in one embodiment, the antimicrobial composition is free of hydrogen peroxide stabilizers. For instance, the antimicrobial composition can be free of one or more hydrogen peroxide stabilizers including phosphorus compounds, polycarboxylic acids, and phosphates. The composition, for instance, may be free of phosphoric acid or derivatives including salts of phosphoric acid. The composition can also be formulated to be free of metal chelators. More particularly, the antimicrobial composition can be formulated so as to not contain one or more of the following hydrogen peroxide stabilizers: phosphoric acid, 1-hydroxyethylidenediphosphonic acid (HEDP), phytic acid, aminophosphate, phosphonate and sodium glutamate, ethylenediamine-N,N’-disuccinic acid, NaF PC Na tripolyphosphate, organophosphonic acid, amino-phosphonate, silver dihydrogen citrate, diphosphonic acid, ethylenediaminetetraacetic acid (EDTA), N-(hydroxyethyl)- ethylenediaminetriacetic acid (HEDTA), ethylenediamine-N,N'-disuccinic acid, a pyridine carboxylic acid base stabilizer such as picolinic acid or dipicolinic acid, 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, succinate or mixtures thereof.

[0041] The antimicrobial composition of the present disclosure is also formulated to promote the stability of hydrogen peroxide and to inhibit hydrogen peroxide from converting into peracetic acid. In addition, the antimicrobial composition is formulated such that no peracetic acid is added to the composition as a component. In one aspect, the antimicrobial composition contains peracetic acid in an amount less than about 1 % by weight, such as in an amount less than about 0.75% by weight, such as in an amount less than about 0.50% by weight, such as in an amount less than about 0.25% by weight. In one particular embodiment, the composition is substantially free of peracetic acid.

[0042] 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, pH adjusting agents, emulsifiers, fragrances, dyes, preservatives, antifoam agents and mixtures thereof.

[0043] 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 2% by weight, such as from about 0.01 % to about 1 % by weight.

[0044] The antimicrobial composition can also contain one or more pH adjusting agents. For many applications, the composition has a pH of less than about 7, such as less than about 5, such as less than about 4, such as less than about 3, such as less than about 2, such as less than about 1. In one aspect, the pH adjusting agent can comprise a base that increases the pH. For instance, the base can comprise a hydroxide, such as sodium hydroxide, potassium hydroxide, ammonium hydroxide, calcium hydroxide, magnesium hydroxide, or mixtures thereof. The pH adjusting agent can be present in the antimicrobial composition generally in an amount from about 0.01 % by weight to about 4% by weight. For instance, the pH adjusting agent can be present in the composition in an amount greater than about 0.1% by weight, such as in anamount greater than about 0.3% by weight, and less than about 1 .5% by weight, such as less than about 1 .3% by weight.

[0045] 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.

[0046] In one embodiment, a relatively concentrated antimicrobial composition is produced that contains hydrogen peroxide in an amount from about 20% to about 70% by weight, such as from about 22% to about 65% by weight, one or more organic sulfonic acids or salts thereof in an amount of from about 5% to about 35% by weight, such as from about 15% to about 25% by weight, and one or more carboxylic acids in an amount of from about 5% to about 35% by weight. Other ingredients may be present, which may reduce the water content.

[0047] In another embodiment, the concentrated composition contains only inert components and / or all the components except the hydrogen peroxide. The hydrogen peroxide can be added to the concentrate at the time of use. For example, the concentrated composition can contain one or more organic sulfonic acids in an amount of from about 5% to about 35% by weight, such as from about 15% to about 25% by weight, and one or more carboxylic acids in an amount of from about 5% to about 35% by weight. An aqueous hydrogen peroxide solution can then be added to the concentrated composition at the time of use in a manner that produces desired concentrations of the components. The aqueous hydrogen peroxide solution can contain hydrogen peroxide in an amount of from about 5% by weight to about 80% by weight, including all increments of 0.5% by weight therebetween. In one aspect, the aqueous hydrogen peroxide solution can contain hydrogen peroxide in an amount less than about 24.5% by weight, such as in an amount of from about 18% by weight to about 24% by weight.

[0048] 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 inthe 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.

[0049] The antimicrobial composition can be applied to an opposing surface using various methods and techniques. For instance, the antimicrobial composition can be sprayed onto the opposing surface or an object can be dipped into the composition.

[0050] One particularly useful application method is to impregnate the antimicrobial composition into a wipe substrate. The wipe can be a single use wipe that is impregnated with the antimicrobial composition and is stored in a container that will dispense the wipe to a user. The container with the wipes may contain a single wipe, or several wipes. Suitable containers include a pouch containing a single wipe, such as a moist towelette which is torn open by the user, or may be a pouch or other container with a resealable opening containing several wipes in a stacked fashion, a rolled fashion or other suitable formation that would allow a single wipe to be removed from the opening at a time. Pouches are generally prepared form a fluid impervious material, such as a film, a coated paper or foil or other similar fluid impervious materials. In another way to dispense wipes of the present disclosure is to place the wipe into a fluid impervious container having an opening to access the wipes in the container. Containers may be molded plastic container with lids that are fluid impervious. Generally, the lid will have an opening to access the wipes in the container. The wipe in the container may be in an interleaved stack, such that as a wipe is removed from the container, the next wipe is positioned in the opening of the container ready for the user to remove the next wipe. Alternatively, the wipe may be a continuous material which is perforated between the individual wipes of the continuous material. The continuous wipe material with perforations may be in a folded form or may be in a rolled form. Usually, in the rolled form, the wipe material is fed from the center of the rolled material. As with the interleaved stack, as a wipe is removed from the container, the next wipe is positioned in the opening to facilitate removal of the next wipe, when needed.

[0051] The antimicrobial composition can be impregnated into the wipe such that the wipe is pre-moistened and will express or release the antimicrobial composition onto the surface as the wipe is run across the surface to be treated. Generally, the antimicrobial composition is saturated into the wipe such that the wipe will release the antimicrobial composition to the surface through the wiping action. Generally, the antimicrobial composition is present in an amount of from about 2 parts to 6 parts by weight per 1 part by weight of the wiper substrate, more preferably from about 3 to about 5 parts by weight per 1 part by weight of the wiper substrate. In these ranges, complete saturation of the substrates can be achieved. It is noted that the amount of the antimicrobial composition may go up or down to achieve complete saturation of the wipe substrate, depending on the particular wipe substrate.

[0052] Suitable wipe substrates include woven and nonwoven materials. Essentially any nonwoven web material may be used. Exemplary nonwoven materials may include, but are not limited to meltblown, coform, spunbond, airlaid, hydroentangled nonwovens, spunlace, bonded carded webs, and laminates thereof. Optionally, the nonwoven may be laminated with a film material as well. The fibers used to prepare the wipe substrate may be cellulosic fiber, thermoplastic fibers and mixtures thereof. The fibers may also be continuous fibers, discontinuous fibers, staple fibers and mixtures thereof. Basis weights of the nonwoven web may vary from about 12 grams per square meter to 200 grams per square meter or more.

[0053] Once applied to the surface, the antimicrobial composition is allowed to remain on the surface for a period of time. As mentioned, it has been unexpectedly found that the described antimicrobial composition has dramatically reduced contact times necessary for killing the targeted microorganisms.

[0054] The present disclosure may be better understood with reference to the following examples.ExamplesExample No. 1

[0055] The following examples demonstrate some of the advantages and benefits of the present disclosure.

[0056] Various different antimicrobial formulations were produced and tested against Clostridium difficile. The following test procedure was used:ASTM Standard E2197-11. Standard Quantitative Disk Carrier Test Method (QCT-2) for Determining Bactericidal, Virucidal, Fungicidal, Mycobactericidal and Sporicidal Activities of Chemicals.Table 1 below lists the formulations that were prepared and tested. The ingredients were mixed at room temperature. The order of addition was not critical for preparing the antimicrobial compositions of the present disclosure. It was noticed that the formulations containing lower amounts of acetic acid, particularly 2% acetic acid, have significantly lower odor than known commercial products that contain greater levels of acetic acid and peracetic acid.Table 1

[0057] The above liquid formulations were evaluated for efficacy against Clostridium difficile (C. difficile) spores at 2 minute, 3 minute, 4 minute, and 5 minute contact time using the ASTM Quantitative Carrier test Method (ASTM E2197-11). The following results were obtained.Table 2* Passing criteria: >6.0 logio reduction

[0058] As shown above, the antimicrobial composition of the present disclosure showed excellent efficacy against the microorganism even after short contact times.

[0059] The samples in Table 1 were also tested for stability. In particular, the formulations were stored in an oven at a temperature of 54°C. The percentage of the active hydrogen peroxide in the formulations was measured at the time when the formulation was prepared and then measured weekly during the stability storage period. The percentage of hydrogen peroxide loss was calculated by the following formula:[Initial H2O2 % - H2O2 % (after storage in oven)] / lnitial H2O2 % x 100

[0060] The stability test results are shown in Table 3 below.Table 3** Formulations were prepared at around 5.0-5.2% H2O2

[0061] As shown above, all of the formulations displayed less than 5% hydrogen peroxide loss at 54°C after two weeks, which is equivalent to one year shelf life at room temperature. The stability results are unexpected and dramatic, especially in view of the fact that no hydrogen peroxide stabilizers were present in the formulations. Reducing the amount of carboxylic acid in the formulation led to a more stable product.

[0062] As shown above, the antimicrobial composition of the present disclosure can display a hydrogen peroxide loss of less than about 2%, such as less than about 1 % after storage at 54°C for one week or for two weeks.

[0063] Wipe substrates were saturated with Sample Nos. 6 and 7 and also tested for stability. The wipe substrates were made from 100% polypropylene fibers. The wipe substrates were ERHT bonded and not pretreated with any surfactants. The loading ratio of liquid to wipe substrate was 4:1 on a weight basis. The wipes were stored in an oven at 54°C for four weeks. The initial hydrogen peroxide concentration was determined and then measured weekly during the stability study. The results are shown in Tables 4 and 5. Table 4 illustrates the results using Sample No. 6 while Table 5 illustrates the results using Sample No. 7.Table 4. Stability test results for Sample No. 6 WipesTable 5. Stability test results for Sample No. 7 Wipes

[0064] As shown above, the hydrogen peroxide concentration decreased by no more than 5%, even after four weeks. The hydrogen peroxide concentration decreased by no more than 2%, such as by no more than about 1 .5% after three weeks. These results are surprising and dramatic in that the composition does not contain a hydrogen peroxide stabilizer.Example No. 2

[0065] The following example demonstrates further advantages and benefits of the present disclosure.

[0066] Various different antimicrobial formulations were produced and tested as follows.

[0067] Table 6

[0068] The above samples were tested for stability as described in Example No. 1. The results are in Table 7 below. As shown in Table 7, it was noticed that organic sulfonic acids, namely, BSA (Sample No. 10), TSA (Sample No. 11 ) as well as dodecylbenzene sulfonic acid sodium salt (Sample No. 12) showed similar stability profiles in formulations comprising high hydrogen peroxide levels.

[0069] Table 7

[0070] The antimicrobial composition of Sample No. 10 and Sample No. 11 showed the lowest percent loss of hydrogen peroxide. For example, Sample No. 10 lost about 4.69% of hydrogen peroxide and Sample No. 11 lost about 4.38% of hydrogen peroxide. It was noticed, however, that Sample No. 9, which did not contain any organic sulfonic acid or salt thereof exhibited a higher hydrogen peroxide percent loss than the above noted Sample Nos. 10 and 11 , which included BSA and TSA, respectively.

[0071] It was surprisingly found that less hydrogen peroxide is lost when the composition contains at least one organic sulfonic acid or salt thereof, even if in small amounts, as compared to a similar or otherwise nearly identical composition which does not contain any organic sulfonic acid or salt thereof. These results are surprising and dramatic in that the composition does not contain a hydrogen peroxide stabilizer.Example No. 3

[0072] Various different antimicrobial formulations containing different carboxylic acids and salts thereof were produced and tested as follows.

[0073] Table 8

[0074] The above samples were evaluated for efficacy against Clostridium difficile (C.difficile) spores after a 3 minute contact time as described in Example No. 1 . As shown in Table 9 below, it was found that the antimicrobial compositions displayed good efficacy when the carboxylic acid utilized in the composition had a carbon chain length between C1 and C5 (e.g., formic acid, acetic acid, citric acid).

[0075] Table 9* Passing criteria: >6.0 logw reduction

[0076] Sample Nos. 13-15 which included formic acid, acetic acid, and glycolic acid, respectively, were effective against C. difficile when about 8% w / w of hydrogen peroxide along with about 1-4% w / w of MSA were present in the composition. Surprisingly, these example compositions displayed a 6 Iog10 reduction or greater after a 3 minute contact time or less when tested against Clostridium difficile according to ASTM Test Method E2197-11 .

[0077] 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 an aqueous solution, the aqueous solution comprising: hydrogen peroxide present in the composition in an amount of at least about 1 % by weight; an organic sulfonic acid or a salt thereof; a Ci to C14 carboxylic acid present in the composition in an amount greater than about 0.1 % by weight; and wherein the composition has a pH less than 4 and wherein the composition displays a 6 log reduction or greater after a 10 minute contact time or less when tested against Clostridium difficile according to ASTM Test Method E2197-1 1 .

2. An antimicrobial composition as defined in claim 1 , wherein the organic sulfonic acid or salt thereof comprises a C1-C5 alkylsulfonic acid, a sulfonated C1-C5 carboxylic acid, a substituted or unsubstituted aromatic sulfonic acid, mono-alkylphenylsulfonic acid, a di-alkylphenylsulfonic acid, or salts thereof or mixtures thereof, wherein the substituted aromatic sulfonic acid is substituted with at least one C1-C3 alkyl group.

3. An antimicrobial composition as defined in any of the preceding claims, wherein the organic sulfonic acid or salt thereof comprises methane sulfonic acid, benzene sulfonic acid, toluene sulfonic acid, or salts thereof, or mixtures thereof.

4. An antimicrobial composition as defined in any of the preceding claims, wherein the organic sulfonic acid or salt thereof is present in the composition in an amount from about 0.1 % by weight to about 6% by weight, such as in an amount from about 0.2% by weight to about 4% by weight.

5. An antimicrobial composition as defined in any of the preceding claims, wherein the hydrogen peroxide is present in the composition in relation to the organic sulfonic acid or salt thereof at a weight ratio of from about 40:1 to about 1 :2, such as from about 12:1 to about 5: 1 .

6. An antimicrobial composition as defined in any of the preceding claims, wherein the hydrogen peroxide is present in the composition in an amount from about 1 % to about 8% by weight, such as in an amount from about 3% to about 6.5% by weight.

7. An antimicrobial composition as defined in any of the preceding claims, wherein the composition is free of pyridine carboxylic acid based stabilizers, such as picolinic acid and / or dipicolinic acid.

8. An antimicrobial composition as defined in any of the preceding claims, wherein the composition is free of 1-hydroxyethylidene-1 ,1-diphosphinic acid.

9. An antimicrobial composition as defined in any of the preceding claims, wherein the composition displays a 6 logw reduction or greater after a 5 minute contact time when tested against Clostridium difficile according to ASTM Test Method E2197-11.

10. An antimicrobial composition as defined in any of the preceding claims, wherein the C1-C4 carboxylic acid comprises acetic acid.

11. An antimicrobial composition as defined in any of the preceding claims, wherein the C1-C14 carboxylic acid is present in the composition in an amount from about 0.5% by weight to about 6% by weight.

12. An antimicrobial composition as defined in any of the preceding claims, wherein the composition further comprises a nonionic surfactant.

13. An antimicrobial composition as defined in any of the preceding claims, wherein the composition further comprises an anionic surfactant.

14. An antimicrobial composition as defined in claim 13, wherein the anionic surfactant comprises a linear alkylbenzene sulfonic acid or salt thereof, an alkyl sulfate, an alkanolamide sulfate, an ethoxylated alkylphenol, or mixtures thereof.

15. An antimicrobial composition as defined in claim 13, wherein the anionic surfactant comprises sodium dodecylbenzene sulfonate.

16. An antimicrobial composition as defined in any of the preceding claims, wherein the composition further contains a pH adjusting agent.

17. An antimicrobial composition as defined in claim 16, wherein the pH adjusting agent comprises sodium hydroxide.

18. An antimicrobial composition as defined in any of the preceding claims, wherein after storage at 54°C for one week, the composition displays a hydrogen peroxide loss of less than about 2%.

19. An antimicrobial composition as defined in any of the preceding claims, wherein after storage at 54°C for two weeks, the composition displays a hydrogen peroxide loss of less than about 5% by weight, such as less than about 1 % by weight.

20. A premoistened wipe comprising: an absorbent substrate; and antimicrobial composition as defined in any of the preceding claims impregnated into the absorbent substrate.21 . A premoistened wipe as defined in claim 20, wherein the antimicrobial composition is impregnated into the absorbent substrate in an amount of from about 2 parts to 6 parts by weight antimicrobial composition per 1 part by weight of the absorbent substrate.

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