BOOSTERS FOR ANTIMICROBIAL, PRESERVATIVE AND BIOCIDAL APPLICATIONS

Abstract

Antimicrobial compounds for use in boosting the efficacy of known antimicrobial, preservative or biocidal compositions. Methods of boosting antimicrobial activity of known compositions, even at low use concentrations, is achieved through adding a booster compound to the known antimicrobial, preservative or biocidal compositions. Use of boosted antimicrobial compositions in end-use applications or products is also described.

Claims

1-23. (canceled)

24. An antimicrobial composition having enhanced or boosted antimicrobial activity against a wide range of microorganisms when used in an end use product, consisting of: a booster compound for enhancing antimicrobial activity of an organic acid or salt thereof or an alcohol or mixtures thereof, present in amounts of 0.005 wt. % to 5 wt. %, in combination with: a) an organic acid or salt thereof comprising benzoic acid, sorbic acid, citric acid, lactic acid, sodium citrate, propionic acid, sodium benzoate, potassium benzoate, potassium sorbate, sodium sorbate, or sodium lactate, or mixtures thereof, present in amounts of 0.005 wt. % to 10 wt. %; or b) an alcohol comprising benzyl alcohol, 2,4 dichlorobenzyl alcohol, or benzyl ethanol, or mixtures thereof, present in amounts of 0.005 wt. % to 10 wt. %; or c) a mixture of a and b, wherein the booster compound is benzylamine, ethylenediaminetetraacetic acid or sodium salt thereof (EDTA), sodium gluconate, glutamic acid N,N-diacetic acid tetrasodium salt (GLDA-Na.sub.4), or caprylyl glycol, or mixtures thereof, wherein the booster compound provides synergistic and improved antimicrobial effects or preservation as compared to that achieved with an organic salt or acid thereof or alcohol alone or in combination, wherein the antimicrobial compositions achieve a two-day or 14-day, two-log reduction of at least two organisms selected from the group consisting of Pseudomonas aeruginosa, Staphylococcus aureus, Aspergillus brasiliensis, Candida albicans, and Escherichia coli, and wherein the wt. % are based upon the total weight of components of an end use product in which it is used.

25. The antimicrobial composition according to claim 24, wherein the organic acid (or salt thereof) comprises sodium benzoate, wherein the alcohol comprises benzyl alcohol, and wherein the booster compound comprises sodium gluconate.

26. The antimicrobial composition according to claim 24, wherein the organic acid or salt thereof comprises sodium benzoate, wherein the alcohol comprises benzyl alcohol, and wherein the booster compound comprises caprylyl glycol.

27. The antimicrobial composition according to claim 24, wherein the organic acid or salt thereof comprises sodium benzoate, wherein the alcohol comprises benzyl alcohol, and wherein the booster compound comprises ethylenediaminetetraacetic acid or sodium salt thereof.

28. The enhanced antimicrobial composition according to claim 24, wherein the organic acid or salt thereof comprises sodium benzoate, wherein the alcohol comprises benzyl alcohol, and wherein the booster compound comprises glutamic acid N,N-diacetic acid tetrasodium salt (GLDA-Na.sub.4).

29. The antimicrobial composition according to claim 24, wherein the end use product comprises household products, laundry products, detergents, healthcare products, medical products, veterinary products, disinfectants, cosmetics, personal care products, skin lotions, industrial products, waterborne coatings, hair care products, paints, coatings, inks, lacquers, adhesives, sealants, caulks, plastisols, polymeric dispersions, polymeric emulsions, pharmaceutical compositions, or oil and gas recovery and drilling compositions.

30. The antimicrobial composition according to claim 24, wherein the booster compound is sodium gluconate, wherein the organic acid or salt thereof is sodium benzoate, wherein the alcohol is benzyl alcohol, and wherein the end-use product is a hair-conditioning shampoo.

31. The antimicrobial composition according to claim 24, wherein the booster compound is sodium gluconate, wherein the organic acid or salt thereof is sodium benzoate, wherein the alcohol is benzyl alcohol, and wherein the end-use product is a skin lotion.

32. The antimicrobial composition according to claim 24, wherein the booster compound is ethylenediaminetetraacetic acid or sodium salt thereof, wherein the organic acid or salt thereof is sodium benzoate, wherein the alcohol is benzyl alcohol, and wherein the end-use product is a skin lotion.

33. The antimicrobial composition according to claim 24, wherein the booster compound is caprylyl glycol, wherein the organic acid or salt thereof is sodium benzoate, wherein the alcohol is benzyl alcohol, and wherein the end-use product is a skin lotion.

34. A concentrated antimicrobial blend, consisting of: a. a booster compound present in amounts of 0.01 wt. % to 90 wt. %, based on the total weight of the concentrated antimicrobial blend; b. an organic acid or salt thereof comprising benzoic acid, citric acid, sorbic acid, lactic acid, sodium benzoate, potassium benzoate, potassium sorbate, sodium sorbate, or sodium lactate, or mixtures thereof; c. an alcohol comprising benzyl alcohol, 2,4 dichlorobenzyl alcohol, or benzyl ethanol, or mixtures thereof, wherein the organic acid or salt thereof and non-booster alcohol are added in amounts sufficient so that the amounts of all of the components total 100 wt. %, based on the total weight of the concentrated antimicrobial blend, and wherein the booster compound is benzylamine, ethylenediaminetetraacetic acid or sodium salt thereof (EDTA), sodium gluconate, glutamic acid N,N-diacetic acid tetrasodium salt (GLDA-Na.sub.4), or caprylyl glycol, or mixtures thereof.

35. The concentrated antimicrobial blend according to claim 34, further diluted with a solvent.

36. The concentrated antimicrobial blend of claim 35, wherein the solvent is water, isopropyl alcohol, propylene glycol, dipropylene glycol, diethylene glycol dibenzoate, dipropylene glycol dibenzoate, propylene glycol dibenzoate, 3-phenyl propyl benzoate, acetone, ethyl acetate, n-butyl acetate, propylene glycol n-butyl ether, dipropylene glycol n-butyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, dipropylene glycol dimethyl ether, xylene, toluene, tetrahydrofuran, chloroform, methyl ethyl ketone, cyclohexane or mixtures thereof.

37. A booster compound for improving the antimicrobial efficacy of preservatives in waterborne coatings or paints, consisting of benzylamine present in amounts ranging from 0.01 wt. % to 5 wt. %, based on the total weight of the waterborne coating or paint,

38. A method of boosting the antimicrobial efficacy of an antimicrobial or preservative composition comprising an organic acid or salt thereof or an alcohol, or mixtures thereof, comprising the step of: adding a boosting compound to the antimicrobial composition, wherein the booster compound comprises benzylamine, ethylenediaminetetraacetic acid or sodium salt thereof (EDTA), sodium gluconate, glutamic acid N,N-diacetic acid tetrasodium salt (GLDA-Na.sub.4), or caprylyl glycol, or mixtures thereof, wherein the organic acid or salt thereof comprises benzoic acid, sorbic acid, citric acid, lactic acid, sodium citrate, propionic acid, sodium benzoate, potassium benzoate, potassium sorbate, sodium sorbate, or sodium lactate, or mixtures thereof, and wherein the alcohol comprises benzyl alcohol, 2,4 dichlorobenzyl alcohol, or benzyl ethanol, or mixtures thereof.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0040] FIG. 1 reflects log reduction data for colony forming units (CFU) of microbe strains exposed to various concentrations of EDTA in tryptic soy broth growth media at pH 6.5 after 30 minutes, with each formulation having a fixed concentration of 0.25 wt. % sodium benzoate and 0.25 wt. % benzyl alcohol.

[0041] FIG. 2 reflects log reduction data of colony forming units (CFU) of microbe strains exposed to EDTA concentrations in tryptic soy broth growth media at pH 6.5 after two days. Each formulation had a fixed concentration of 0.25 wt. % of sodium benzoate and 0.25 wt. % of benzyl alcohol.

[0042] FIG. 3 reflects log reduction data of colony forming units (CFU) of microbe strains exposed to EDTA concentrations in tryptic soy broth growth media at pH 6.5 after fourteen days. Each formulation had a fixed concentration of 0.25 wt. % of sodium benzoate and 0.25 wt. % of benzyl alcohol.

[0043] FIG. 4 reflects log reduction data of colony forming units (CFU) of microbe strains exposed to EDTA concentrations in tryptic soy broth growth media at pH 6.5 after twenty-eight days. Each formulation had a fixed concentration of 0.25 wt. % of sodium benzoate and 0.25 wt. % of benzyl alcohol.

[0044] FIG. 5 reflects log reduction data of colony forming units (CFU) of microbe strains exposed to sodium gluconate concentrations in tryptic soy broth growth media at pH 6.5 after 30 minutes. Each formulation had a fixed concentration of 0.25 wt. % of sodium benzoate and 0.25 wt. % of benzyl alcohol.

[0045] FIG. 6 reflects log reduction data of colony forming units (CFU) of microbe strains exposed to sodium gluconate concentrations in tryptic soy broth growth media at pH 6.5 after two days. Each formulation had a fixed concentration of 0.25 wt. % of sodium benzoate and 0.25 wt % of benzyl alcohol.

[0046] FIG. 7 reflects log reduction data of colony forming units (CFU) of microbe strains exposed to sodium gluconate concentrations in tryptic soy broth growth media at pH 6.5 after fourteen days. Each formulation had a fixed concentration of 0.25 wt. % of sodium benzoate and 0.25 wt. % of benzyl alcohol.

[0047] FIG. 8 reflects log reduction data of colony forming units (CFU) of microbe strains exposed to sodium gluconate concentrations in tryptic soy broth growth media at pH 6.5 after twenty-eight days. Each formulation had a fixed concentration of 0.25 wt. % of sodium benzoate and 0.25 wt. % of benzyl alcohol.

[0048] FIG. 9 reflects log reduction data of colony forming units (CFU) of microbe strains exposed to caprylyl glycol concentrations in tryptic soy broth growth media at pH 6.5 after 30 minutes. Each formulation had a fixed concentration of 0.25 wt. % of sodium benzoate and 0.25 wt. % of benzyl alcohol.

[0049] FIG. 10 reflects log reduction data of colony forming units (CFU) of microbe strains exposed to caprylyl glycol concentrations in tryptic soy broth growth media at pH 6.5 after two days. Each formulation had a fixed concentration of 0.25 wt. % of sodium benzoate and 0.25 wt. % of benzyl alcohol.

[0050] FIG. 11 reflects log reduction data of colony forming units (CFU) of microbe strains exposed to EDTA concentrations in tryptic soy broth growth media at pH 8 after 30 minutes. Each formulation had a fixed concentration of 0.25 wt. % of sodium benzoate and 0.25 wt. % of benzyl alcohol.

[0051] FIG. 12 reflects log reduction data of colony forming units (CFU) of microbe strains exposed to EDTA concentrations in tryptic soy broth growth media at pH 8 after two days. Each formulation had a fixed concentration of 0.25 wt. % of sodium benzoate and 0.25 wt. % of benzyl alcohol.

[0052] FIG. 13 reflects log reduction data of colony forming units (CFU) of microbe strains exposed to EDTA concentrations in tryptic soy broth growth media at pH 8 after fourteen days. Each formulation had a fixed concentration of 0.25 wt. % of sodium benzoate and 0.25 wt. % of benzyl alcohol.

[0053] FIG. 14 reflects log reduction data of colony forming units (CFU) of microbe strains exposed to EDTA concentrations in tryptic soy broth growth media at pH 8 after twenty-eight days. Each formulation had a fixed concentration of 0.25 wt. % of sodium benzoate and 0.25 wt. % of benzyl alcohol.

[0054] FIG. 15 reflects log reduction data of colony forming units (CFU) of microbe strains exposed to sodium gluconate concentrations in tryptic soy broth growth media at pH 8 after 30 minutes. Each formulation had a fixed concentration of 0.25 wt. % of sodium benzoate and 0.25 wt. % of benzyl alcohol.

[0055] FIG. 16 reflects log reduction data of colony forming units (CFU) of microbe strains exposed to sodium gluconate concentrations in tryptic soy broth growth media at pH 8 after two days. Each formulation had a fixed concentration of 0.25 wt. % of sodium benzoate and 0.25 wt. % of benzyl alcohol.

[0056] FIG. 17 reflects log reduction data of colony forming units (CFU) of microbe strains exposed to sodium gluconate concentrations in tryptic soy broth growth media at pH 8 after fourteen days. Each formulation had a fixed concentration of 0.25 wt. % of sodium benzoate and 0.25 wt. % of benzyl alcohol.

[0057] FIG. 18 reflects log reduction data of colony forming units (CFU) of microbe strains exposed to sodium gluconate concentrations in tryptic soy broth growth media at pH 8 after twenty-eight days. Each formulation had a fixed concentration of 0.25 wt. % of sodium benzoate and 0.25 wt. % of benzyl alcohol.

[0058] FIG. 19 reflects log reduction data of colony forming units (CFU) of microbe strains exposed to caprylyl glycol concentrations in tryptic soy broth growth media at pH 8 after 30 minutes. Each formulation had a fixed concentration of 0.25 wt. % of sodium benzoate and 0.25 wt. % of benzyl alcohol.

[0059] FIG. 20 reflects log reduction data of colony forming units (CFU) of microbe strains exposed to caprylyl glycol concentrations in tryptic soy broth growth media at pH 8 after two days. Each formulation had a fixed concentration of 0.25 wt. % of sodium benzoate and 0.25 wt. % of benzyl alcohol.

[0060] FIG. 21 reflects log reduction data of colony forming units (CFU) of microbe strains exposed to 3-phenyl propanol concentrations in skin lotion media at pH 6.5 after two days. Each formulation had a fixed concentration of 0.25 wt. % of sodium benzoate and 0.25 wt. % of benzyl alcohol.

[0061] FIG. 22 reflects log reduction data of colony forming units (CFU) of microbe strains exposed to 3-phenyl propanol concentrations in skin lotion media at pH 6.5 after 14 days. Each formulation had a fixed concentration of 0.25 wt. % of sodium benzoate and 0.25 wt. % of benzyl alcohol.

[0062] FIG. 23 reflects log reduction data of colony forming units (CFU) of microbe strains exposed to sodium benzoate, benzyl alcohol, and EDTA concentrations in skin lotion media at pH 6.5 after two days. Each formulation had a fixed concentration of 0.5 wt. % of sodium benzoate and 0.25 wt. % of EDTA, with varying concentrations of benzyl alcohol. Control is comprised of 0.5 wt. % sodium benzoate and 1 wt. % benzyl alcohol without EDTA.

[0063] FIG. 24 reflects log reduction data of colony forming units (CFU) of microbe strains exposed to sodium benzoate, benzyl alcohol, and EDTA concentrations in skin lotion media at pH 6.5 after 14 days. Each formulation had a fixed concentration of 0.5 wt. % of sodium benzoate and 0.25 wt. % of EDTA with varying concentrations of benzyl alcohol. Control is comprised of 0.5 wt. % sodium benzoate and 1 wt. % benzyl alcohol without EDTA.

[0064] FIG. 25 reflects log reduction data of colony forming units (CFU) of microbe strains exposed to sodium benzoate, benzyl alcohol, and sodium gluconate concentrations in skin lotion media at pH 6.5 after two days. Each formulation had a fixed concentration 0.5 wt. % of sodium benzoate and 0.25 wt. % of sodium gluconate with varying concentrations of benzyl alcohol. Control is comprised of 0.5 wt. % sodium benzoate and 1 wt. % benzyl alcohol without sodium gluconate.

[0065] FIG. 26 reflects log reduction data of colony forming units (CFU) of microbe strains exposed to sodium benzoate, benzyl alcohol, and sodium gluconate concentrations in skin lotion media at pH 6.5 after 14 days. Each formulation had a fixed concentration 0.5 wt. % of sodium benzoate and 0.25 wt. % of sodium gluconate, with varying concentrations of benzyl alcohol. Control is comprised of 0.5 wt. % sodium benzoate and 1 wt. % benzyl alcohol without sodium gluconate.

[0066] FIG. 27 reflects log reduction data of colony forming units (CFU) of microbe strains exposed to sodium benzoate, benzyl alcohol, and caprylyl glycol concentrations in skin lotion media at pH 6.5 after two days. Each formulation had a fixed concentration 0.25 wt. % of sodium benzoate and 0.25 wt. % benzyl alcohol, with varying concentrations of caprylyl glycol. Control is comprised of 0.5 wt. % sodium benzoate and 1 wt. % benzyl alcohol without caprylyl glycol.

[0067] FIG. 28 reflects log reduction data of colony forming units (CFU) of microbe strains exposed to sodium benzoate, benzyl alcohol, and caprylyl glycol concentrations in skin lotion media at pH 6.5 after 14 days. Each formulation had a fixed concentration 0.25 wt. % of sodium benzoate and 0.25 wt % benzyl alcohol, with varying concentrations of caprylyl glycol. Control is comprised of 0.5 wt. % sodium benzoate and 1 wt. % benzyl alcohol without caprylyl glycol.

[0068] FIG. 29 reflects log reduction data for colony forming units (CFU) of microbe strains in tryptic soy broth growth media at pH 9.0 up to 28 days.

[0069] FIG. 30 reflects log reduction data for colony forming units (CFU) of microbe strains exposed to benzylamine at 2.5 wt. % in tryptic soy broth at pH 9.0 up to one week.

DETAILED DESCRIPTION OF THE INVENTION

[0070] The invention is directed to compositions having improved antimicrobial, biocidal or preservative efficacy against a wide range of microorganisms as described herein. In particular, the invention is directed to use of a booster compound in combination with known antimicrobial, preservative or biocidal compounds to achieve improved antimicrobial, preservative, or biocidal efficacy over that achieved without use of the booster compounds.

[0071] The invention is also directed to methods for enhancing the antimicrobial or preservative performance of known antimicrobial, preservative or biocidal compounds by adding a booster compound to the compounds. In particular, the invention is directed to methods for enhancing the antimicrobial or preservative efficacy of organic acids (or salts thereof) or alcohols, or mixtures thereof. In a preferred embodiment, the invention is directed to enhancing the antimicrobial activity of sodium benzoate- and benzyl alcohol-containing compositions to improve antimicrobial performance, although the invention is not limited to sodium benzoate and benzyl alcohol compositions. Antimicrobial activity of other organic acids (or salts thereof) and/or alcohols described herein may also be boosted by use of the compounds and methods of the invention.

[0072] Finally, the invention is directed to end use applications, products and compositions comprising the enhanced antimicrobial compositions of the invention.

[0073] For purposes of this invention, the terms microorganisms, microbiological organisms, and microbes shall mean and include bacteria, fungi, yeast, molds, protozoa, and viruses and are used interchangeably herein. The invention is directed to use of antimicrobial compositions against a wide variety of microorganisms including without limitation Gram positive bacteria, Gram negative bacteria, fungi, mold, yeast, protozoa and viruses.

[0074] Antimicrobial and biocidal shall mean and include the ability of the inventive antimicrobial compositions to prevent, reduce, deter, eliminate or render harmless, any harmful microorganism by chemical means and are used interchangeably herein. Preservative may also be used to describe the antimicrobial and biocidal effects of the inventive compositions, or an end use application for the antimicrobial compositions of the invention.

[0075] Activity, efficacy, effectiveness or performance, with respect to antimicrobials, refer to the antimicrobial functions of the inventive compositions that are improved through the use of booster compounds of the invention.

[0076] Concentrations of components are expressed in weight percent (wt. %), and the weight percent is based upon the total weight of an end use product unless otherwise stated.

[0077] The terms enhancer, booster, enhanced, boosted, enhancing or boosting, in context, are used interchangeably herein to refer to the synergistic and improved antimicrobial effects or preservation achieved through the use of compounds that, unexpectedly, increase or improve antimicrobial efficacy of known antimicrobial compounds in an end use composition.

[0078] The unexpected results of the invention are achieved by adding sufficient amounts of certain compounds that may themselves have some slight or low antimicrobial activity to boost the antimicrobial or preservative activity of organic acids (or salts thereof) and alcohols traditionally used as antimicrobials, biocides or preservatives, such as sodium benzoate and benzyl alcohol, to achieve improved antimicrobial or preservative activity not achieved with the use of organic acids (or salts thereof) or alcohols alone or in combination. The invention takes advantage of the unexpected synergism of booster compounds and known antimicrobial compounds, in combination, to achieve an antimicrobial composition that exhibits improved antimicrobial or preservative efficacy and is considered environmentally safe, free of adverse and toxic effects and effective at low use levels. The inventive compositions should also withstand scrutiny of regulatory and industry standard-setting agencies.

[0079] Suitable booster compounds for use in the invention include a chelating agent such as EDTA, sodium gluconate, glutamic acid, N,N-diacetic acid tetrasodium salt (GLDA-Na.sub.4), an alcohol such as 3-phenyl propanol, a glycol such as caprylyl glycol, or an amine such as benzylamine, or mixtures thereof.

[0080] The booster compounds of the invention are preferably used in combination with sodium benzoate and benzyl alcohol, although the invention is not limited as such, Other organic acids (and salts thereof), other alcohols or other preservatives traditionally used in certain end use applications, which are known to have antimicrobial activity, may also be useful in combination with the booster compounds of the invention.

[0081] Exemplary organic acids and salts thereof including without limitation: benzoic acid, sorbic acid, citric acid, propionic acid, lactic acid, fumaric acid, sodium benzoate, potassium benzoate, sodium citrate, potassium sorbate, sodium sorbate, or sodium lactate, or mixtures thereof. Exemplary non-booster alcohols include without limitation ethanol, propanol, benzyl alcohol, 2,4 dichlorobenzyl alcohol, benzyl ethanol, phenyl ethanol or phenoxyethanol, or mixtures thereof.

[0082] The booster compounds of the invention may also be used in combination with traditional preservatives specific to certain end use applications, which are not organic acids or salts thereof or alcohols, to improve antimicrobial efficacy of the traditional preservatives or reduce the amounts of traditional preservatives required.

[0083] Amounts of booster compounds useful in the inventive compositions vary according to the compound utilized. By way of non-limiting example, amounts of 3-phenyl propanol range from 0.005 wt. % to 1.99 wt. %. Amounts of EDTA range from 0.005 wt. % to 5 wt. %. Amounts of sodium gluconate range from 0.005 wt. % to 5 wt. %. Amounts of GLDA-Na.sub.4 range from 0.005 wt. % to 5 wt. %. Amounts of caprylyl glycol useful in the inventive compositions range from 0.005 wt. % to 5 wt. %. Amounts of benzylamine range from 0.005 wt. % to 5 wt. %. If mixtures of the booster compounds of the invention are utilized, the total amount utilized ranges from 0.005 wt. % to 5 wt. %. Depending on the particular use application, one skilled in the art would be able to determine suitable amounts of useful boosters.

[0084] Amounts of sodium benzoate suitable for use in the inventive compositions range from 0.005 wt. % to 10 wt. %, and amounts of benzyl alcohol range from 0.005 wt. % to 10 wt. %. Useful amounts of other organic acids (and salts thereof) and other alcohols also fall within these ranges.

[0085] Suitable amounts of each compound may vary within the stated range depending upon end use applications, concentration and type of other components, compatibilities, interactions, pH of the final product, and regulatory and industry standard considerations, as one skilled in the art would understand.

[0086] The antimicrobial compositions of the invention may also be provided in concentrated form for ease of handling and costs. Concentrated forms are particularly useful in the manufacturing process. Concentrated blends of the antimicrobial components are within the scope of the invention. Generally, a concentrated antimicrobial blend of the invention is prepared by adding the booster compound in amounts ranging from about 0.01 wt. % to 90 wt. %, to a combination of an organic acid or salt thereof and an alcohol, wherein the organic acid or salt thereof and alcohol are added in amounts sufficient so that the amounts of all of the components of the concentrated antimicrobial blend total 100 wt. %, as based on the total weight of the components of the concentrated antimicrobial blend.

[0087] One non-limiting example includes 3-phenyl propanol in amounts ranging from 30.2 wt. % to 99.5 wt. %, alone or in combination with an organic acid (or its salt) and an alcohol. A particularly preferred embodiment for 3-phenyl propanol is an antimicrobial blend comprising 41 wt. % of 3-phenyl propanol, 29.5 wt. % sodium benzoate, and 29.5 wt. % benzyl alcohol.

[0088] Non-limiting examples of solvents that may be used to dilute the concentrated antimicrobial compositions of the invention include without limitation water, ethanol, propanol, isopropyl alcohol, propylene glycol, dipropylene glycol, diethylene glycol dibenzoate, dipropylene glycol dibenzoate, propylene glycol dibenzoate, 3-phenyl propyl benzoate, acetone, ethyl acetate, n-butyl acetate, propylene glycol n-butyl ether, dipropylene glycol n-butyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, dipropylene glycol dimethyl ether, xylene, toluene, tetrahydrofuran, chloroform, methyl ethyl ketone, cyclohexane or mixtures thereof. Other solvents suitable for use with the inventive antimicrobial compositions or in the particular end use applications utilizing them will be known to one skilled in the art.

[0089] The inventive antimicrobial compositions are described with respect to efficacy in tryptic soy broth, which is an excellent surrogate for evaluating antimicrobial efficacy in water-based or aqueous applications. End use applications for the inventive antimicrobial compositions are described with respect to use in skin lotion formulations, waterborne coatings, and hair conditioning and shampoo applications; however, the end uses are not intended to be limited as such. Non-limiting end-use applications for the inventive antimicrobial compositions include household products, laundry products, detergents, cleaners, cosmetics, toiletries, personal care compositions, disinfectants, healthcare products, medical products, veterinary products, pharmaceuticals, and consumer products. Non-limiting examples of industrial end-use applications include paint, coatings, lacquers, inks, adhesives, caulks, sealants, plastisols and other polymeric dispersions and emulsions, and compositions for use in oil and gas recovery and drilling processes. The inventive compositions are especially useful for aqueous based formulations, both water soluble or using water as a carrier. Still other end-use applications will be evident to one skilled in the art.

[0090] While the boosted antimicrobial compositions of the invention are useful in a variety of end-use products and applications, end-use products and applications comprising the boosted compositions are within the scope of the invention.

[0091] The invention is illustrated by the examples set forth below, which are not intended to be limiting.

EXAMPLES

[0092] Methodology and Materials

[0093] Challenge Testing MethodologyExperimentalSeveral industry standard testing methodologies exist for evaluating antimicrobial efficacy. Two common examples of such standards include United States Pharmacopeia (USP 51) and European Pharmacopeia (EP) testing methodology. These methodologies are particularly useful in that they have criteria and methodologies distinguishing between oral products, topical products and pharmaceutical products, among others.

[0094] In conducting the testing, the compound or product to be evaluated is separated out into individual containers, each being challenged with one of the method-specified microorganisms (S. aureusATCC 6538 USP51/EP, E. coliATCC 8739 EP, P. aeruginosaATCC 9027 USP51/EP, C. albicansATCC 10231 USP51/EP, and A. brasiliensisATCC 16404 USP51/EP) at a concentration of >110.sup.5 CFU/g or ml. The initial concentration of each microorganism is determined by inoculating a control substance and using standard dilution and plating techniques. At the time of test initiation, a separate volume, typically 1 ml or 1 g, of the compound or product to be evaluated is diluted in a volume of chemical neutralizer broth, i.e., inoculated, to be used in the neutralization and recovery validation. The inoculated broth is held at room temperature and is evaluated at specific intervals. USP-51 evaluates at the 14-day and 28-day intervals. EP evaluates results at 2-day, 7-day, 14-day, and 28-day. At each contact time, the inoculated product is chemically neutralized and plated using standard dilution and plating techniques. After a period of incubation (48 hours for bacteria, up to 5 days for yeast and mold) surviving microorganisms are counted, and the log reduction of each microorganism at each interval is reported.

[0095] For the European Pharmacopeia, a pass test for efficacy is a two-log reduction for bacteria after two days, a three-log reduction in bacteria after three days, a two-log reduction in mold and yeast at 14 days and no increase at 28 days. For the USP-51, a two-log reduction in bacteria is required at 14 days and no increase at 28 days. For mold and yeast, USP-51 requires no increase at 14 days and 28 days. No increase is defined as a 0.5 log reduction.

[0096] Tryptic soy broth, commonly referred to as soybean-casein digest medium or tryptic soy broth, is used as a growth medium to cultivate a wide variety of microorganisms. Tryptic soy broth is an exceptionally difficult environment to preserve as it is an ideal growth medium for microbes with optimized levels of water and nutrients. As such, it is an exceptional test medium for evaluating antimicrobial efficacy and serves as a useful surrogate particularly for waterborne applications. The general tryptic soy broth formula (per liter) is listed in the table below.

TABLE-US-00001 Formula per Liter Casein Digest Peptone 17.0 g Papaic Digest of Soybean Meal 3.0 g Dipotassium Phosphate 2.5 g Sodium Chloride 5.0 g Dextrose 2.5 g

[0097] Skin Lotion Formulation ExperimentalAn exemplary, model skin lotion having a pH of 6.5 as set forth below in Table 1 was prepared for testing. The invention is not limited to use in this specific lotion but was used to illustrate the advantages of the invention.

TABLE-US-00002 TABLE 1 Skin Lotion Formulation INCI Name Wt. % Function Stage A Water Varies Carrier Glycerin 5.0% Humectant Xantham Gum 0.1% Rheology Modifier Chelators or Glycols Varies Stage B Cetearyl Alcohol 3.0% Rheology Modifier Steareth-21 2.0% Emulsifier Steareth-2 2.0% Emulsifier Mineral Oil 5.0% Emollient Petrolatum 2.0% Emollient Stage C Sodium Benzoate Varies Preservative Benzyl Alcohol Varies Preservative 3-Phenyl propanol Varies Antimicrobial

[0098] The challenge testing was conducted by a Food and Drug Administration (FDA) certified outside testing lab utilizing standard USP-51 and European Pharmacopeia methodologies as summarized in the Challenge Testing Methodology section above. Antimicrobial efficacy was determined in tryptic soy broth growth media, pH-balanced with sodium hydroxide or hydrochloric acid as required to achieve specific pH ranges. Use applications involve products having a variety of pH conditions. As such, efforts were made to assess efficacy over a typical range of pH conditions.

Example 1Tryptic Soy Broth Studies, pH 6.5, EDTA

[0099] The boosting efficacy of various concentrations of EDTA (0 to 0.5 wt. %, with 0 being a control without the EDTA booster) in tryptic soy broth growth media at pH 6.5 was evaluated against various microbes (A. brasiliensis, C. albicans, E. coli, P. aeruginosa, and S. aureus). Each soy broth formulation contained a fixed amount of 0.25 wt. % sodium benzoate and 0.25 wt. % benzyl alcohol.

[0100] The data reflected in FIGS. 1 through 4 shows the improved antimicrobial performance achieved by the addition of EDTA at 30 minutes, two days, fourteen days and twenty-eight days.

[0101] The data demonstrated antimicrobial boosting potential of EDTA in aqueous applications utilizing sodium benzoate and benzyl alcohol. The data also demonstrated that EDTA is effective at boosting antimicrobial activity of an organic acid salt (sodium benzoate) and an alcohol (benzyl alcohol) at low use concentrations, with particularly good activity against Pseudomonas aeruginosa at two-days.

Example 2Tryptic Soy Broth Studies, pH 6.5, Sodium Gluconate

[0102] Studies were conducted in the same manner and against the same microbes as Example 1 to evaluate the boosting efficacy of various concentrations of sodium gluconate (0 to 0.5 wt %, with 0 being a control without sodium gluconate) in tryptic soy broth comprising 0.25 wt. % sodium benzoate and 0.25 wt. % benzyl alcohol. Data was reported at 30 minutes, two days, fourteen days and twenty-eight days.

[0103] FIGS. 5 through 8 show the boosting performance of sodium gluconate at pH 6.5. Good activity was seen against the mold A. brasiliensis at 14 and 28 days.

[0104] The data demonstrated the antimicrobial boosting potential of sodium gluconate in combination with sodium benzoate and benzyl alcohol in aqueous applications, showing increased log reduction with increased concentration of sodium gluconate. While not as strong a booster as EDTA in this media and with the sodium benzoate/benzyl alcohol combination, the increase in log reduction was seen at 14 days and 28 days in the tryptic soy broth studies, which is a particularly appropriate surrogate for waterborne or aqueous applications.

Example 3Tryptic Soy Broth Studies, pH 6.5, Caprylyl Glycol

[0105] Studies were conducted in the same manner and against the same microbes as Example 1 to evaluate the boosting efficacy of various concentrations of caprylyl glycol (0 to 5 wt. %, with 0 being a control without caprylyl glycol) in tryptic soy broth comprising 0.25 wt. % sodium benzoate and 0.25 wt. % benzyl alcohol. Data was reported at 30 minutes and two days.

[0106] FIGS. 9 and 10 show the performance of caprylyl glycol and reflect a two-day, two-log reduction achieved against all microbes tested regardless of concentration of caprylyl glycol.

[0107] The data demonstrated outstanding antimicrobial boosting potential for caprylyl glycol at the lowest use concentration (1 wt. %). Caprylyl glycol has a known added advantage in certain applications of functioning as a skin conditioning agent, making it very useful for cosmetic and personal care product preservation.

Example 4Tryptic Soy Broth Studies, pH 8, EDTA

[0108] The boosting efficacy of various concentrations of EDTA (0 to 0.5 wt. % as in Example 1) in tryptic soy broth growth media at pH 8 was evaluated against the same microbes as utilized in Example 1. Each soy broth formulation contained a fixed amount of 0.25 wt. % sodium benzoate and 0.25 wt % benzyl alcohol.

[0109] The data reflected in FIGS. 11 through 14 shows the improved antimicrobial performance achieved by the combination of sodium benzoate, benzyl alcohol and EDTA at 30 minutes, two days, fourteen days and twenty-eight days, respectively. The data demonstrated antimicrobial boosting potential of EDTA in aqueous applications showing increased log reduction with increasing concentrations at pH 8.0.

Example 5Tryptic Soy Broth Studies, pH 8, Sodium Gluconate

[0110] The antimicrobial performance of various concentrations (0-0.5 wt. % as in Example 2) of sodium gluconate in tryptic soy broth growth media at pH 8 was evaluated in combination with sodium benzoate and benzyl alcohol present in the same concentrations as in Example 4. The data was collected at 30 minutes, two days, fourteen days and twenty-eight days.

[0111] FIGS. 15 through 18 show the improved antimicrobial performance achieved by sodium gluconate in combination with sodium benzoate and benzyl alcohol. Particularly good activity was demonstrated against the mold A. brasiliensis at 14 and 28 days.

Example 6Tryptic Soy Broth Studies, pH 8, Caprylyl Glycol

[0112] The performance of various concentrations (at the same concentrations as Example 3) of caprylyl glycol in tryptic soy broth growth media was evaluated in combination with sodium benzoate and benzyl alcohol present in the same concentrations as in Example 4. Data was collected at 30 minutes and two days.

[0113] FIGS. 19 and 20 show improved antimicrobial performance achieved by caprylyl glycol in combination with low concentrations of sodium benzoate and benzyl alcohol in tryptic soy broth at pH 8. The results reflect a two-day, two-log reduction achieved against all microbes tested regardless of concentration of caprylyl glycol. The data also demonstrated versatility of caprylyl glycol against a wider pH range.

Example 7Skin Lotion Studies, 3-Phenyl Propanol

[0114] In this example, 3-phenyl propanol was used to enhance the performance of low concentrations of sodium benzoate and benzyl alcohol. This example evaluated boosting performance of 3-phenyl propanol in a skin lotion formulation having a pH of 6.5, the ingredients of which are listed in Table 1. Each formulation contained 0.25 wt. % of sodium benzoate and 0.25 wt. % of benzyl alcohol.

[0115] The log reduction of the microbes reflected in FIGS. 21 and 22 show that without the addition of 3-phenyl propanol, the formulations were not suitable to meet the challenging two-day, two-log reduction of P. aeruginosa and S. aureus outlined in the European Pharmacopeia method. In this example, 0.35 wt. % addition of 3-phenyl propanol enhanced the antimicrobial nature of the skin lotion to an extent that antimicrobial performance met the two-day and 14-day criteria set forth in the European Pharmacopeia summarized in the Challenge Testing Methodology section above.

Example 8Skin Lotion Studies, EDTA

[0116] In this example, EDTA was used to enhance the performance of sodium benzoate and benzyl alcohol in a skin lotion formulation at pH, the ingredients of which are set forth in Table 1. Each formulation contained 0.5 wt. % of sodium benzoate and 0.25 wt. % of EDTA with benzyl alcohol varying up to 1 wt. %. The control was comprised of 0.5 wt. % sodium benzoate and 1 wt. % benzyl alcohol without EDTA.

[0117] The log reduction of the microbes in FIGS. 23 and 24 show that without the addition of 0.25 wt. % EDTA, the skin lotion formulations comprising only sodium benzoate and benzyl alcohol were not suitable to meet the challenging two-day, two-log reduction of P. aeruginosa and S. aureus outlined in the European Pharmacopeia method (as summarized in the Challenge Testing Methodology section above) even at the higher use amounts of sodium benzoate and benzyl alcohol (0.5 wt. % and 1 wt. %, respectively). In this example, 0.25 wt. % addition of EDTA enhanced the antimicrobial nature of the formulation to an extent that antimicrobial performance met the two-day criteria set forth in the European Pharmacopeia with 0.5 wt. % sodium benzoate and 1 wt % benzyl alcohol. In this example, FIG. 24 shows that 0.25 wt. % addition of EDTA enhanced the antimicrobial nature of the formulation to an extent that antimicrobial performance met the 14-day criteria set forth in the European Pharmacopeia with concentrations of 0.5 wt. % sodium benzoate and 0.66 wt. % benzyl alcohol.

Example 9Skin Lotion Studies, Sodium Gluconate

[0118] In this example, sodium gluconate was used to enhance the performance of sodium benzoate and benzyl alcohol in a skin lotion formulation at pH 6.5, the ingredients of which are set forth in Table 1. Each formulation contained 0.5 wt. % of sodium benzoate and 0.25 wt. % of sodium gluconate, with benzyl alcohol varying up to 1 wt. %. The control comprised 0.5 wt. % sodium benzoate and 1 wt. % benzyl alcohol without sodium gluconate.

[0119] The log reduction of the microbes in FIGS. 25 and 26 show that without the addition of sodium gluconate, the formulations were not suitable to meet the challenging two-day, two-log reduction of P. aeruginosa and S. aureus outlined in the European Pharmacopeia method (summarized in the Challenge Testing Methodology section above) even at higher use levels of sodium benzoate and benzyl alcohol. In this example, 0.25 wt. % addition of sodium gluconate enhanced the antimicrobial nature of the formulation to an extent that antimicrobial performance met the two-day criteria set forth in the European Pharmacopeia with 0.5 wt. % sodium benzoate and 1 wt. % benzyl alcohol. In this example, FIG. 26 shows that the 0.25 wt. % addition of sodium gluconate enhanced the antimicrobial nature of the formulation to an extent that antimicrobial performance met the 14-day criteria set forth in the European Pharmacopeia with 0.5 wt. % sodium benzoate and 0.66 wt. % benzyl alcohol.

Example 10Skin Lotion Studies, Caprylyl Glycol

[0120] In this example, caprylyl glycol was used to enhance the performance of sodium benzoate and benzyl alcohol in a skin lotion formulation at pH 6.5, the ingredients of which are set forth in Table 1. FIGS. 27 and 28 reflect log reduction data of colony forming units (CFU) of microbe strains exposed to sodium benzoate, benzyl alcohol, and caprylyl glycol concentrations in skin lotion media after two and fourteen days. Each formulation had a fixed concentration 0.25 wt. % of sodium benzoate and 0.25 wt. % benzyl alcohol. A control was utilized comprising 0.5 wt. % sodium benzoate and 1 wt. % benzyl alcohol without caprylyl glycol.

[0121] The log reduction of the microbes in FIGS. 27 and 28 show that without the addition of caprylyl glycol, the formulations were not suitable to meet the challenging two-day, two-log reduction of P. aeruginosa and S. aureus outlined in the European Pharmacopeia method (as summarized in the Challenge Testing Methodology section above) even at higher use levels of sodium benzoate and benzyl alcohol. In this example, 0.5 wt. % addition of caprylyl glycol enhanced the antimicrobial nature of the formulation to an extent that antimicrobial performance met the two-day and 14-day criteria set forth in the European Pharmacopeia.

Example 11 Tryptic Soy Broth Studies at pH 9.0

[0122] FIG. 30 shows antimicrobial effectiveness achieved by benzylamine alone at pH 9 in tryptic soy broth compared to a control (FIG. 29, no benzylamine). Strains of K. aerogenes (ATCC 13048) and P. aeruginosa (ATCC 9027) were utilized for testing as they are commonly found in many water-based products, including without limitation cosmetics and coatings. These organisms were challenged into the soy broth using the same methods as in the other examples. Time points were selected based on time points from ASTM 2574, which is a method for evaluating antimicrobial efficacy in waterborne emulsion based paints. Results for 2.5 wt. % benzyl alcohol (not shown) were exactly the same as for benzylamine.

[0123] The foregoing examples demonstrated boosted antimicrobial performance of sodium benzoate and benzyl alcohol when combined with a booster compound that is a chelating agent such as EDTA, sodium gluconate, an alcohol such as 3-phenyl propanol or a glycol such as caprylyl glycol. This enhanced performance was seen in tryptic soy broth studies, an excellent surrogate for evaluating performance in water-based or aqueous applications. The results demonstrated the capability for the inventive boosting technology in aqueous applications up to pH 8.0. Boosting capability was also demonstrated in a skin care formulation, achieving antimicrobial performance to meet stringent criteria with two-day, two-log reductions of bacteria at pH 6.5.

[0124] Additional non-limiting examples below describe use of the inventive boosters to improve antimicrobial efficacy of traditional preservatives used in specific end use applications and/or to reduce the amount of traditional preservatives required to achieve antimicrobial efficacy. Booster compounds of the invention achieve an improvement in antimicrobial efficacy of traditional preservatives against various microorganisms common to specific end use applications and at pH levels common to the applications, including without limitation in waterborne latex coatings at appropriate coatings pH levels and in a hair conditioner/shampoo. The booster compounds achieve improvement in antimicrobial efficacy even when used with traditional preservatives that are not organic acids or salts thereof or alcohols. Improved efficacy allows for a reduction in the amount of preservatives traditionally used or required to achieve antimicrobial effects.

Example 12Waterborne Coating/Paint

[0125] The following example is a waterborne coating with a polymer emulsion binder. The addition of benzylamine at levels ranging from 0.01 to 5 wt. %, along with traditional preservatives used in paint or coating formulations, produces improved antimicrobial efficacy and/or preservation as compared to that achieved with the use of the traditional preservatives alone, including without limitation benzoisothiazolinone, methylisothiazolinone, or methylchloroisothiazolinone. Improved efficacy may mean using less of the traditional preservatives. An exemplary waterborne coating formulation using benzylamine according to the invention is set forth below in Table 2.

TABLE-US-00003 TABLE 2 Waterborne Coating Formulation Component Weight (lb) Function Grind Water 107 Carrier Tamol 851 10 Dispersant Byk 28 2 Defoamer Kronos TiO.sub.2 487 Pigment Letdown Water 52 Carrier Raycryl 1207 330 Polymer Emulsion Binder Coalescent 10 Coalescent Benzylamine 10 Antimicrobial Preservative Q.S. Preservative Natrosol HBR 2 Rheology Modifier

Example 13Two-in-One Hair Conditioner/Shampoo

[0126] The following example is a two-in-one hair conditioner/shampoo, i.e., hair conditioning shampoo. The addition of sodium gluconate at the use level listed below, along with traditional preservatives sodium benzoate and benzyl alcohol, produces improved antimicrobial efficacy and/or preservation for the hair conditioner/shampoo formulation over that achieved with use of traditional preservatives alone. Improved efficacy may mean using less of the traditional preservatives.

TABLE-US-00004 TABLE 3 2 in 1 Hair Conditioner/Shampoo Formulation Component Wt. % Function Deionized Water Q.S. Carrier SLS 7.0 Surfactant SLES-2 6.0 Surfactant Cocoamidopropyl betaine 2 Cosurfactant Cocamide MEA 2 Cosurfactant Polyquaternium 10 0.1 Conditioning Polymer NaCl 1.5 Rheology Modifier Sodium Benzoate 0.5 Preservative Benzyl Alcohol 0.2 Preservative Sodium Gluconate 0.25 Antimicrobial

[0127] While in accordance with the patent statutes the best mode and preferred embodiment have been set forth, the scope of the invention is not limited thereto, but rather by the scope of the attached claims.