Skin cleansing composition

Abstract

The present invention relates to skin cleansing compositions, in particular skin cleansing compositions that provide improved antimicrobial benefits. The skin cleansing composition comprises a surfactant, preferably soap, and an adduct of an amine or diamine with an acid; and a pH in the range of from 4.0 to 10.5, wherein the acid is a monocarboxylic acid or a dicarboxylic acid.

Description

Technical Field

[0001] The present invention relates to skin cleansing compositions. In particular, the present invention relates to skin cleansing compositions that provide improved antimicrobial benefits. Background Art

[0002] Microorganisms, such as bacteria, tend to colonize surfaces, such as human skin. If some of these microorganisms enter the human system, such as through cuts in the skin and through the act of ingestion, they may trigger harmful effects. Therefore, it is generally desirable to maintain hygiene by excluding such damage-causing microorganisms. For example, people tend to wash their hands from time to time using skin cleansing compositions to help maintain hygiene.

[0003] Several skin cleansing compositions providing antimicrobial benefits are known in the art, such as hand washing or bathing compositions. Such skin cleansing compositions are available in solid form, such as bars such as soap bars; and in liquid form, such as liquid hand / body wash compositions. Typically, the antimicrobial benefit provided by such skin cleansing compositions is delivered by one or more active substances that may be present in such skin cleansing compositions. For example, skin cleansing compositions comprising antimicrobial active substances (e.g., triclosan) are known in the art.

[0004] Although antimicrobial skin cleansing compositions already exist, people tend to seek newer technologies that provide improved benefits, such as improved antimicrobial benefits, such as the benefits being exerted in a very short period of time of less than 5 minutes, preferably less than 3 minutes, more preferably less than 1 minute, and ideally within 10 to 30 seconds. Another improved benefit is killing of Gram-negative bacteria (such as E. coli) and Gram-positive bacteria (such as Staphylococcus aureus). Therefore, skin cleansing compositions that provide improved antimicrobial benefits remain a subject of interest.

[0005] It has now been discovered that skin cleansing compositions comprising a surfactant, preferably a soap, and an adduct of a selected amine or diamine with an acid having a pH within a selected range provide improved antimicrobial benefits.

[0006] It is an object of the present invention to provide a skin cleansing composition which achieves antimicrobial kill in a very short period of time.

[0007] It is yet another object of the present invention to provide a skin cleansing composition that kills both Gram-negative and Gram-positive bacteria. Summary of the invention

[0008] In a first aspect, the present invention relates to a skin cleansing composition comprising:

[0009] i. 1-85 wt% of a surfactant; and

[0010] ii. 0.1-15% by weight of an adduct of an amine or diamine with an acid,

[0011] iii. pH adjuster;

[0012] wherein the pH of the composition is 4.0-10.5;

[0013] The acid is a monocarboxylic acid or a dicarboxylic acid.

[0014] In a second aspect, the present invention relates to a method for providing an antimicrobial effect comprising the steps of:

[0015] a. applying the composition of the first aspect to a surface; and

[0016] b. Clean the surface within 5 minutes of performing step a.

[0017] In a third aspect, the present invention relates to the use of an adduct of an amine or diamine with an acid, wherein the acid is a monocarboxylic acid or a dicarboxylic acid, for providing an antimicrobial effect in a composition comprising a surfactant at a pH of 4.0 to 10.5. DETAILED DESCRIPTION

[0018] Any feature of one aspect of the present invention can be used for any other aspect of the present invention. The word "comprising" is intended to mean "including", but not necessarily "consisting of" or "consisting of". In other words, the steps or options listed do not need to be exhaustive. Except in the operating examples and comparative examples, or where otherwise explicitly indicated, all numbers in this specification indicating the amount of material or reaction conditions, the physical properties of the material and / or the use thereof should be understood to be modified by the word "about". Numerical ranges expressed in the form of "x to y" should be understood to include x and y. When multiple preferred ranges are described in the form of "x to y" for a particular feature, it should be understood that all ranges combining different endpoints are also covered. Unless otherwise indicated, the amount used herein is expressed in weight percentage based on the total weight of the composition and can be abbreviated as "weight %". The use of any and all examples or exemplary language such as "such as" provided herein is intended only to better illustrate the present invention, and does not limit the scope of the present invention otherwise claimed in any way.

[0019] For the purposes of the present invention, the terms "antimicrobial benefit" or "antimicrobial effect" or "antimicrobial efficacy" can be used interchangeably and they mean the same. Preferably, "antimicrobial benefit" or "antimicrobial effect" or "antimicrobial efficacy" means reducing the number of microorganisms (e.g., bacteria, fungi and viruses). Such an antimicrobial effect is obtained when the composition of the present invention is preferably applied to a surface, which may be an inanimate or animate surface; and the step of washing the surface is performed within 5 minutes of the step of applying the composition. More preferably, the composition is applied to an animate substrate, such as human skin. As used herein, "skin" is preferably meant to include skin on any part of the body, such as the face, neck, chest, back, arms, underarms, hands, legs, buttocks and scalp.

[0020] In a first aspect, the present invention relates to a skin cleansing composition according to the present invention (the composition) comprising:

[0021] i. 1-85 wt% of a surfactant; and

[0022] ii. 0.1-15% by weight of an adduct of an amine or diamine with an acid, and

[0023] iii. pH adjuster,

[0024] The pH of the composition is 4.0-10.5,

[0025] The acid is a monocarboxylic acid or a dicarboxylic acid.

[0026] When used on a surface (animate or inanimate surface, preferably an animate surface), the composition provides an antimicrobial effect. Preferably, the antimicrobial effect is obtained in a time period as short as less than 5 minutes, such as 1 minute, 30 seconds and 15 seconds.

[0027] Adducts of amines or diamines with acids

[0028] The composition comprises an adduct of an amine or a diamine with an acid, i.e. it comprises an adduct formed of an amine with an acid; or an adduct formed of a diamine with an acid. An adduct of an amine with an acid is a preferred adduct.

[0029] Preferably, the amine is selected from alkyl-substituted primary or secondary or tertiary amines, wherein the alkyl group is a linear or branched group formed by 2 to 8 carbon atoms and contains hydroxyl (-OH) substitutions. Examples of alkyl-substituted primary or secondary or tertiary amines (wherein the alkyl group is a linear or branched group formed by 2 to 8 carbon atoms and contains hydroxyl (-OH) substitutions) that can be used as amines include monoethanolamine (MEA), diethanolamine (DEA), triethanolamine (TEA), monoisopropanolamine (MIPA), diisopropanolamine (DIPA), triisopropanolamine (TIPA) and mixtures thereof. Preferably, MEA, DEA and mixtures thereof are used as amines.

[0030] Preferably, the diamine is selected from:

[0031] - acyl (RC=O) substituted diamines, wherein R is an alkyl group having 1 to 8, preferably 1 to 4, linear or branched carbon atoms,

[0032] - alkylenediamines, wherein the alkylene group is formed from 2 to 8, preferably 2 to 4, linear or branched carbon atoms; and mixtures thereof.

[0033] Examples of acyl substituted diamines include tetraacetylethylenediamine, diacetylethylenediamine, and mixtures thereof. Examples of alkylenediamines (wherein the alkylene group is formed from 2 to 8 carbon atoms) that can be used as amines include ethylenediamine, propylenediamine, butylenediamine, and mixtures thereof.

[0034] Preferably, the amine or diamine so selected is a non-volatile amine.

[0035] Preferably, the acid is selected from carboxylic acids with a pKa in the range of 2.5 to 5.5. The acid is preferably a monocarboxylic acid or a dicarboxylic acid. Further more preferably, the acid is selected from acetic acid (AA), glycolic acid, tartaric acid, salicylic acid, benzoic acid and mixtures thereof; still more preferably, the acid is selected from acetic acid, glycolic acid and mixtures thereof.

[0036] Examples of adducts so formed include adducts formed from an amine (e.g., monoethanolamine) and an acid (e.g., acetic acid), MEA-AA. Likewise, another example of such adducts is the diethanolamine salt of acetic acid (DEA-AA) and the triethanolamine salt of acetic acid (TEA-AA). The adducts so formed have been found to provide an antimicrobial effect.

[0037] The composition comprises 0.1 to 15 wt %, preferably 0.5 to 13 wt %, more preferably 1 to 11 wt %, even more preferably 2 to 10 wt %, further more preferably 3 to 7 wt %, still more preferably 4 to 6 wt % of the adduct of the amine or diamine with the acid.

[0038] pH Adjuster:

[0039] The composition of the present invention comprises a pH adjusting agent, which is a water-soluble compound that adjusts the pH of the composition to the desired range. The pH adjusting agent that can be used is selected from one or more of sodium bicarbonate, potassium bicarbonate, sodium bisulfate, potassium bisulfate, lactic acid, tartaric acid, citric acid or a dilute solution of an inorganic acid such as hydrochloric acid or sulfuric acid. The pH adjusting agent is usually added to the composition to bring it to a pH below 10.5, preferably below 10.3. In the case of a soap bar, the pH adjusting agent is added to the soap composition before the adduct is added.

[0040] Surfactants

[0041] The composition comprises a surfactant. Preferably, the surfactant is selected from anionic surfactants, nonionic surfactants, cationic surfactants, amphoteric surfactants and mixtures thereof. More preferably, the surfactant is selected from anionic surfactants, amphoteric surfactants and mixtures thereof.

[0042] Anionic surfactants

[0043] Preferably, the anionic surfactant is selected from the group consisting of synthetic anionic surfactants, soaps and mixtures thereof. More preferably, the anionic surfactant is soap.

[0044] Preferably, the synthetic anionic surfactant is selected from alkyl sulfates (AS), alkyl ether sulfates (AES), α-olefin sulfonates (AOS) and mixtures thereof. Examples of AS that can be used as anionic surfactants in the composition include sodium lauryl sulfate (SLS), sodium myristyl sulfate, sodium palmityl sulfate and mixtures thereof. Examples of AES that can be used as anionic surfactants include anionic surfactants of the following general formula:

[0045] R 1 -(OR') n -O-SO 3 - M + ,in:

[0046] R 1 Is saturated or unsaturated C 8 -C 16 , preferably C 12 -C 14 Alkyl chain; preferably, R 1 It is saturated C 8 -C 16 , more preferably saturated C 12 -C 14 Alkyl chain;

[0047] R' is ethylene; n is 1 to 18; preferably 1 to 15, more preferably 1 to 10, even more preferably 1 to 5, and further more preferably 1 to 3,

[0048] M + is a suitable cation providing electroneutrality, preferably sodium, calcium, potassium or magnesium, more preferably a sodium cation.

[0049] Examples of AES that can be used as anionic surfactants in the composition include sodium lauryl ether sulfate (SLES), sodium myristyl ether sulfate and sodium palmityl ether sulfate and mixtures thereof. Preferred AES are SLES having 1 to 3 ethylene oxide units per molecule. SLES having 1 to 2 ethylene oxide units per molecule are more preferred.

[0050] More preferably, soap is used as anionic surfactant in the composition. Preferably, the soap used in this way is formed by fatty acids with a carbon chain length of 8 to 18, more preferably 12 to 16. Preferably, sodium or potassium salts of fatty acids with a carbon chain length of 8-18 (e.g. lauric acid, myristic acid, palmitic acid and oleic acid), alone or as a mixture, can be used as anionic surfactants. For example, sodium laurate, sodium myristate, sodium palmitate, sodium oleate, potassium laurate, potassium myristate, potassium palmitate, potassium oleate and mixtures thereof can be used as anionic surfactants.

[0051] Nonionic surfactants

[0052] Preferably, the nonionic surfactant can be selected from:

[0053] - fatty alcohol ethoxylates with a saturated carbon chain and having an HLB higher than 15.5, for example 35 (also known as L23),

[0054] - fatty alcohol ethoxylates with an unsaturated carbon chain and an HLB value higher than 12, for example 97 and 99,

[0055] -Alkylphenol ethoxylates with HLB above 15; e.g. Triton TM X 405,

[0056] - polyoxyethylene sorbitan alkyl esters having a saturated C12 to C16 carbon chain and having an HLB higher than 12; for example, 20,

[0057] - polyoxyethylene sorbitan alkyl esters having an unsaturated C18 carbon chain and having an HLB higher than 9; for example, 80. 81; and 85; and mixtures thereof.

[0058] Amphoteric surfactant

[0059] When added to the composition, the amphoteric surfactant provides improved foam.Preferably, the amphoteric surfactant is selected from cocamidopropyl betaine (CAPB), cocamide monoethanolamide (CMEA), cocoamphoacetate and mixtures thereof.

[0060] Cationic surfactants

[0061] Preferably, the cationic surfactant can be selected from cetyl trimethyl ammonium chloride, behenyl trimethyl ammonium chloride, cetyl pyridinium chloride, tetramethyl ammonium chloride, tetraethyl ammonium chloride, octyl trimethyl ammonium chloride, dodecyl trimethyl ammonium chloride, cetyl trimethyl ammonium chloride, octyl dimethyl benzyl ammonium chloride, decyl dimethyl benzyl ammonium chloride, stearyl dimethyl benzyl ammonium chloride, didodecyl dimethyl ammonium chloride, dioctadecyl dimethyl ammonium chloride, tallow trimethyl ammonium chloride, dihydrogenated tallow dimethyl ammonium chloride (e.g. Arquad 2HT / 75 from Akzo Nobel), coconut oil trimethyl ammonium chloride, PEG-2-oleammonium chloride and its corresponding hydroxide. Other suitable cationic surfactants include those materials with the CTFA designations quaternary ammonium salt-5, quaternary ammonium salt-31 and quaternary ammonium salt-18. Mixtures of any of the foregoing materials may also be suitable. A particularly useful cationic surfactant is cetyl trimethyl ammonium chloride, for example with Another particularly useful cationic surfactant is behenyltrimethylammonium chloride, available for example as KDMP is commercially available. Yet another preferred cationic surfactant is stearamidopropyl dimethylamine.

[0062] The composition comprises 1 to 85 wt % of a surfactant, preferably 5 to 80 wt %, more preferably 10 to 75 wt %, even more preferably 15 to 70 wt %, still more preferably 25 to 66 wt %, still more preferably 35 to 60 wt %, still further more preferably 40 to 55 wt % of a surfactant.

[0063] pH

[0064] The pH range of the composition is 4.0-10.5, preferably 4.5-10.3, even more preferably 5.0-10.1, further more preferably 5.5-10.0, still more preferably 6.5-10.0, and yet more preferably 8.0-10.0. For example, the pH of the composition is most preferably 7.0 or 7.5. Alternatively, the pH of the composition can be 9.5. The pH of the composition can be adjusted using a suitable pH adjusting agent (e.g., sodium hydroxide and sodium bicarbonate).

[0065] If the composition is in liquid form, preferably the pH of the composition is in the range of 4.0 to 10.5 when measured at 25°C to 35°C before dilution or preferably after diluting the composition to 50% concentration.

[0066] If the composition is in solid form, preferably the pH of the composition is in the range of 4.0 to 10.5 when measured using a 1 to 8% (eg 8%) aqueous solution of the composition in demineralised water at a temperature of 25°C to 35°C.

[0067] Form of composition

[0068] Preferably, the composition is in liquid form or in solid form. More preferably, the composition is in solid form, such as a bar. Even more preferably, the composition is in the form of a soap bar.

[0069] Thus, the composition is preferably a liquid skin cleansing composition comprising:

[0070] i. 1 to 85 wt % of a surfactant; and

[0071] ii. 0.1 to 15% by weight of an adduct of an amine or diamine with an acid,

[0072] wherein the pH of the composition is 4.0 to 10.5, preferably 4.0 to 7.5;

[0073] The acid is a monocarboxylic acid or a dicarboxylic acid.

[0074] Alternatively but preferably, the composition is a solid skin cleansing composition comprising:

[0075] i. 1 to 85 wt % of a surfactant; and

[0076] ii. 0.1 to 15% by weight of an adduct of an amine or diamine with an acid,

[0077] wherein the pH of the composition is 4.0 to 10.5, preferably 8.0 to 10.1;

[0078] The acid is a monocarboxylic acid or a dicarboxylic acid.

[0079] More preferably, the composition is a soap bar composition comprising:

[0080] i. 40 to 85% by weight of soap,

[0081] ii. 0.1 to 15% by weight of an adduct of an amine or diamine with an acid,

[0082] wherein the pH of the composition is from 4.0 to 10.5, preferably from 8.5 to 10.1;

[0083] The acid is a monocarboxylic acid or a dicarboxylic acid.

[0084] Structuring agent

[0085] Preferably, the composition comprises a structuring agent. Preferably, the structuring agent is selected from the group consisting of silica, talc, calcite, pumice, tricalcium phosphate, chalk, Fuller's earth, kaolin, starch, gums, silica gel, sodium polyacrylate, tetraalkyl and / or trialkylaryl ammonium smectite, chemically modified magnesium aluminum silicate, organically modified montmorillonite clay, hydrated aluminum silicate, fumed silica, carboxyvinyl polymers, sodium carboxymethylcellulose, ethylene glycol monostearate, and mixtures thereof.

[0086] Talc is a magnesium silicate mineral material with a sheet silicate structure and Mg 3 Si 4 (OH) 22 It has a plate-like morphology and is essentially oleophilic / hydrophobic, i.e. it is wetted by oil but not by water.

[0087] The starch may be used directly or modified during the preparation of the bar composition such that the starch becomes gelatinized, either partially or completely. Another suitable starch is pregelatinized, which is a starch that is gelatinized prior to addition as an ingredient to the bar composition of the present invention. Various forms are available that gel at different temperatures, such as cold water dispersible starches. Examples of commercially available pregelatinized starches are CS 3400.

[0088] Preferably, the composition comprises a structurant in an amount ranging from 1 to 50 wt%, more preferably from 3 to 45 wt%, even more preferably from 10 to 30 wt%, and further more preferably from 15 to 25 wt%.

[0089] polymer

[0090] Preferably, the composition further comprises a water-soluble polymer. Preferably, such polymer is selected from polyvinyl alcohol, polyvinyl pyrrolidone, sodium carboxymethylcellulose, polyethylene glycol, methylcellulose, hydroxypropyl methylcellulose and mixtures thereof.

[0091] Preferably, the composition comprises 1 to 20 wt%, more preferably 3 to 17 wt%, even more preferably 5 to 15 wt%, further more preferably 7 to 13 wt%, and still more preferably 9 to 12 wt% of the water-soluble polymer.

[0092] Such polymers may be added to the composition mixture or may be used to coat the composition. For example, if the composition is in the form of a bar or tablet, such polymers may form an outer water-soluble coating on such bar or tablet.

[0093] If the composition is formulated in the form of a bar, it preferably comprises a polyhydric alcohol (also referred to as a polyol) or a mixture of polyols. Polyol is a term used herein to represent a compound having multiple hydroxyl groups (at least two, preferably at least three), which is highly water-soluble, preferably readily soluble, in water. Many types of polyols are available, including relatively low molecular weight short-chain polyols such as glycerol and propylene glycol; sugars such as sorbitol, mannitol, sucrose and glucose; modified carbohydrates such as hydrolyzed starch, dextrin and maltodextrin, and polymerized synthetic polyols such as polyalkylene glycols, e.g., polyoxyethylene glycol (PEG) and polyoxypropylene glycol (PPG). Particularly preferred polyols are glycerol, sorbitol and mixtures thereof. The most preferred polyol is glycerol. If the composition is formulated into a bar, it preferably comprises 0 to 8% by weight, more preferably 1 to 7.5% by weight, even more preferably 2 to 5% by weight of a polyol.

[0094] Preferably, the composition also comprises a sunscreen. Examples of sunscreens include titanium dioxide, zinc oxide, etc. An alternative sunscreen is zinc stearate.

[0095] Preferred bars may additionally include up to 30% by weight of benefit agents. Preferred benefit agents include moisturizers, emollients, sunscreens and anti-aging compounds. These benefit agents may be added at an appropriate step in the process of preparing the composition.

[0096] The composition may further comprise one or more of the following ingredients:

[0097] The composition may preferably further comprise a skin lightening agent selected from ammonium lactate, arbutin, azelaic acid, kojic acid, butylated hydroxyanisole, butylated hydroxytoluene, citrate esters, 3-diphenylpropane derivatives, ellagic acid, glucopyranosyl-1-ascorbate, gluconic acid, glycolic acid, hydroquinone, 4-hydroxyanisole, linoleic acid, magnesium ascorbyl phosphate, 2,4-resorcinol derivatives, 3,5-resorcinol derivatives, vitamins such as vitamin B6, vitamin B12, vitamin C, vitamin A, resorcinol derivatives and mixtures thereof.

[0098] If the composition is formulated in solid form, e.g. a bar such as a soap bar, it preferably comprises water in an amount of 10-20 wt%, more preferably 14-18 wt%. Alternatively, if the composition is formulated in liquid form, the composition preferably comprises 40-90 wt% water, more preferably 60-85 wt% water.

[0099] The composition may preferably further comprise a preservative to protect the composition against the growth of potentially harmful microorganisms. Particularly preferred preservatives include hydantoin derivatives, propionates, various quaternary ammonium compounds, phenoxyethanol, imidazolidinyl urea, sodium dehydroacetate and benzyl alcohol. The preservative is preferably used in an amount ranging from 0.01% to 2% by weight.

[0100] Diluents other than water may include liquid or solid emollients, solvents, humectants, thickeners, and powders. Examples of each of these types of vehicles that may be used alone or as a mixture of one or more vehicles are as follows:

[0101] Emollients such as stearyl alcohol, glyceryl monoricinoleate, mink oil, cetyl alcohol, isopropyl isostearate, stearic acid, isobutyl palmitate, isocetyl stearate, oleyl alcohol, isopropyl laurate, hexyl laurate, decyl oleate, octadecane-2-ol, isocetyl alcohol, eicosanol, behenyl alcohol, cetyl palmitate, silicone oils such as dimethicone, di-n-butyl sebacate, isopropyl myristate, isopropyl palmitate, isopropyl stearate, stearic acid Butyl acetate, polyethylene glycol, triethylene glycol, lanolin, cocoa butter, corn oil, cottonseed oil, olive oil, palm kernel oil, rapeseed oil, safflower seed oil, evening primrose oil, soybean oil, sunflower seed oil, avocado oil, sesame oil, coconut oil, peanut oil, castor oil, acetylated lanolin alcohol, petrolatum, mineral oil, butyl myristate, isostearic acid, palmitic acid, isopropyl linoleate, lauryl lactate, myristyl lactate, decyl oleate, myristyl myristate.

[0102] In addition, the composition preferably comprises other optional ingredients, such as antioxidants, spices, polymers, chelating agents, colorants, deodorants, dyes, emollients, humectants, enzymes, foam boosters, foaming agents, skin conditioners, pH regulators and stabilizers, which can be added in suitable amounts. Preferably, these ingredients are added after the saponification step. Preferably, sodium metabisulfite, ethylenediaminetetraacetic acid (EDTA), borax or ethylene hydroxy diphosphonic acid (EHDP) are added to the formulation. These ingredients can be present in the composition in an amount of 0 to 7 % by weight, more preferably 1 to 5 % by weight, and even more preferably 2 to 4 % by weight.

[0103] In a second aspect, the invention relates to a method of providing an antimicrobial benefit comprising the steps of:

[0104] a. applying to a surface the composition according to the first aspect; and

[0105] b. Clean the surface within 5 minutes of performing step a.

[0106] A step a involving applying the composition of the first aspect to a surface. The surface is preferably an inanimate or animate surface. More preferably, the surface is an animate surface, such as human skin. As used herein, "skin" preferably refers to skin on any part of the body, such as the face, neck, chest, back, arms, underarms, hands, legs, buttocks and scalp. Step a is preferably carried out when the user applies the composition of the first aspect to the surface together with water in an amount sufficient to produce foam.

[0107] The method comprises an additional step, step b, wherein the surface to which the composition is applied is cleaned with water to remove the composition from the surface. Preferably, step (b) is carried out in less than 5 minutes, more preferably in less than 3 minutes, even more preferably in less than 1 minute, and further preferably in less than 35 seconds, for example in 10 to 30 seconds after step a. When the method is carried out as described in the second aspect, an antimicrobial benefit is obtained, i.e., microorganisms (e.g., bacteria) are reduced from the surface to which the composition is so applied. Preferably, the method is non-therapeutic and / or cosmetic in nature.

[0108] In a third aspect, the present invention relates to the use of an adduct of an amine or a diamine with an acid in a composition comprising a surfactant and having a pH in the range of 4.0 to 10.5 for providing an antimicrobial effect.

[0109] For example, in this third aspect, the invention relates to the use of MEA-AA or DEA-AA or TEA-AA in a composition comprising a surfactant and having a pH in the range of 4.0 to 10.5 for providing an antimicrobial effect. Preferably, the use is non-therapeutic and / or cosmetic in nature.

[0110] In another aspect, the present invention relates to a method for preparing a skin cleansing composition according to the present invention. Preferably, a composition in solid form (e.g., a soap bar) can be prepared using the following method:

[0111] Adduct formation:

[0112] Adducts are products of addition reactions. The adducts of the present invention are preferably prepared by the following method. The amine is placed in a flask equipped with magnetic beads, a reflux condenser and a dropping funnel. The acid is then added dropwise to the amine solution under vigorous mixing conditions over a period of about 1 hour. It is then mixed continuously for about 8 more hours to complete the reaction. Alternatively, 50% of the amine solution is added to the water in the flask, and 50% of the acid solution is added in batches over about 1 hour, followed by mixing for about 8 more hours. The reaction mixture is then used as is or after extraction with an organic solvent to prepare the composition according to the present invention.

[0113] Soap Formation:

[0114] Preferably, soap bars are prepared using oils such as palm oil (PO) and palm kernel oil in desired ratios (e.g. 80:20 (PO:PKO) by saponification reaction with water, glycerol, electrolytes (e.g. sodium chloride, sodium sulfate, sodium citrate, sodium silicate), preservatives such as EDTA, EHDP and / or fillers. Alternatively, soap bars can be prepared using oils in ratios such as 70:30, 85:15, 90:10 (PO:PKO). Saponification can be carried out by a screw mixer or a continuous saponification tank or a plow shear mixer route, followed by cooling the final mass at a temperature in the range of 30-45°C and extruding into soap bars. Preferably, the soap bars so prepared have PKO values ​​such as 10, 20, 25, 30 and 40; IV (iodine value) in the range of 30-45. Thereafter, the soap bars are extruded in a bow blender for up to 5 minutes. After completion of extrusion of the bars, solid ingredients such as soda are added. Ash and talc and mix for up to 5 minutes. Then add the required amount of pH adjuster such as sodium bicarbonate as needed, mix for up to 3 minutes, then add polymer and colorant (if necessary), and mix for up to 3 minutes. Alternatively, the colorant can be added during the extrusion of the thin strips. Preferably, the adduct of the present invention, that is, the adduct formed by amine and acid or the adduct formed by diamine and acid (as described in the first aspect above) is prepared separately. After the colorant is mixed, the preformed adduct of the present invention, such as MEA-AA, DEA-AA, TEA-AA, is added and mixed for up to 3 minutes. The fragrance is added as the last step and then mixed for up to 3 minutes. After this mixing, the material is processed by a suitable device such as a three-roll mill, and the strips are pressed by a stripping machine to obtain the final soap bar, and stamped as needed. Preferably, the pH of the material before adding the adduct is maintained in the range of 9.5-10.6.

[0115] The present invention will now be further described with reference to the following non-limiting examples:

[0116] Example:

[0117] A skin cleansing composition in the form of a soap bar (shown in Table 2) was prepared as follows:

[0118] Soap bars are prepared by saponification using oils such as palm oil (PO) and palm kernel oil (PKO) in a ratio of 80:20 (PO:PKO) and processed into bars with water, glycerol, electrolytes such as sodium chloride, preservatives such as EDTA, EHDP and / or fillers. The saponification is carried out by a plow shear mixer route. The final mass is cooled to about 40°C and extruded into soap bars. Thereafter, the soap bars are extruded in a bow blender for up to 5 minutes. After the bar extrusion is completed, solid ingredients such as soda ash and talc are added and mixed. The required amount of pH adjuster such as sodium bicarbonate is added as required and mixed for up to 3 minutes, followed by the addition of polymers and colorants (if required) and mixed for up to 3 minutes. After mixing the colorant, a preformed adduct of monoethanolamine and acetic acid (MEA-AA), i.e., monoethanolamine acetate, is added and further mixed for up to 3 minutes. The pH of the mass is maintained in the range of 9.5-10.8 before the addition of the preformed adduct. Finally, the fragrance is added and mixed for up to 3 minutes. After this mixing, the material is processed through a three-roll mill and ploddered to obtain the final strips and stamped as required.

[0119] Antimicrobial Effect:

[0120] The compositions summarized in Table 2 below were evaluated for antimicrobial effects using ASTM 2783 (Standard Test Method for Evaluating the Antimicrobial Activity of Water-Miscible Compounds Using a Time-Kill Procedure). Escherichia coli (ATCC 10536) and Staphylococcus aureus (ATCC 6538) were used as test organisms.

[0121] Preparation of working cultures of test organisms: Approximately 48 hours prior to testing, inoculate a sterile Tryptic Soy Broth (TSB) tube from a glycerol stock containing the challenge (test) microorganism. Incubate the broth culture at 35 ± 2°C for 24 hours. Approximately 24 hours prior to testing, inoculate the broth culture onto the surface of sterile Tryptic Soy Agar (TSA) and incubate at 35 ± 2°C for approximately 24 hours.

[0122] Bacterial challenge test suspension and confirmation test suspension (prepared immediately before use): Prepare a suspension of the challenge microorganism in sterile 0.9% saline and adjust the optical density at 620 nm to obtain approximately 7 × 10 8 cfu / mL to 9×10 8 cfu / mL of challenge suspension concentration. Challenge suspensions were prepared for each replicate tested. Each challenge suspension was used within 2 hours of preparation and maintained at 25 ± 1°C. A neutralization challenge test suspension containing approximately 3000-10000 cfu / mL was prepared in sterile saline by diluting the challenge microorganism.

[0123] Preparation of 8% soap slurry:

[0124] The soap bar sample was finely ground and 8 g was weighed into a sterile bottle. 92 mL of sterile distilled water (DW) was preheated at 50 ± 1 °C and 8 g of the above soap sample was added and mixed using an immersion magnetic stirrer and kept for 25 to 30 minutes to prepare an 8% soap slurry. After 25 to 30 minutes, a 10 mL sample aliquot was transferred to a vial placed at 40 ± 1 °C and kept for 3 to 5 minutes to equilibrate and mix using an immersion magnetic stirrer.

[0125] Evaluation of Bacteria Reduction Efficacy:

[0126] 10mL of the test solution is placed in a vial and kept in a water bath maintained at the test temperature for 3 to 5 minutes to equilibrate. A 0.1 ml aliquot of the challenge suspension is transferred to the vial containing the test solution and mixed thoroughly using an immersion magnetic stirrer. Using a calibrated split-second timer, the challenge suspension is exposed to the test solution for the desired contact time, e.g., less than 5 minutes, e.g., 30 seconds. After the contact time, a 1 mL aliquot is transferred from the vial containing the test solution / challenge suspension to a test tube containing 9.0 mL of a pre-validated neutralizer and mixed thoroughly using a vortex mixer. Prepare an additional 10-fold dilution (10 -2 , 10 -3 , 10 -4 and 10 -5 ). Using the pour plate technique, 1.0 mL aliquots of 10 -1 Up to 10 -5 Each dilution of was plated in duplicate using TSA. Plates were incubated according to the given culture conditions.

[0127] The log reduction of each challenge suspension attributable to the test solution at each timed exposure was calculated for each replicate as follows:

[0128] Log 10 Reduction = Log 10 Average (NC)-Log 10 Average(Pex),

[0129] Where NC = number control cfu / mL population, and Pex = post-exposure population cfu / mL

[0130] Table 1: Noodle composition

[0131] Element weight% Toilet soap without lauric acid 62.2 Lauric acid 10.1 Caustic soda (47.5% solution) 23.2 Refined glycerin 2 PVD salt (NaCl) 0.7 water Up to 100 TFM (calculated) 74.2 Anhydrous soap (surfactant) 80.2

[0132] Using the method as described above, the soap strips shown in Table 1 above were used to make final soap bars (as shown in Table 2 below).

[0133] Table 2: Soap bar composition

[0134]

[0135]

[0136] *Polymers, colorants and fragrances

[0137] The data in Table 2 show that the compositions according to the present invention (Examples 1-4) exert better antimicrobial efficacy than compositions outside the present invention (Examples BF). Example A includes acetic acid and exerts good antimicrobial efficacy, but is found to lack a pleasant odor that is desirable in consumer products such as soap bars. Acetic acid and strong mineral acids present this organoleptic problem. Therefore, this problem is overcome (in addition to the enhanced antimicrobial efficacy) by using the adducts described in the present invention.

Claims

1. A skin cleaning composition comprising: i. 1-85 wt% of a surfactant; and ii. 0.1-15% by weight of an adduct of an amine or diamine with an acid, and iii. pH adjuster; The pH of the composition is 4.0-10.5, The acid is a monocarboxylic acid or a dicarboxylic acid.

2. The composition of claim 1, wherein the adduct is an adduct of an amine and an acid.

3. The composition of claim 1 or 2, wherein the amine is selected from alkyl-substituted primary, secondary or tertiary amines, wherein the alkyl group is a straight or branched chain group formed from 2 to 8 carbon atoms and contains a hydroxyl (-OH) substitution.

4. The composition of claim 3, wherein the amine is selected from the group consisting of monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, triisopropanolamine, and mixtures thereof.

5. The composition of claim 4, wherein the amine is selected from the group consisting of monoethanolamine, diethanolamine, and mixtures thereof.

6. The composition of claim 1, wherein the diamine is selected from: i. acyl (RC=O) substituted diamines, wherein R is an alkyl group of 1 to 8 straight or branched carbon atoms; and ii. Alkylenediamines, wherein the alkylene group is formed by 2 to 8 straight-chain or branched carbon atoms; and mixtures thereof.

7. The composition of any one of claims 1-6, wherein the acid is selected from carboxylic acids having a pKa in the range of 2.5-5.

5.

8. The composition of claim 7, wherein the acid is selected from the group consisting of acetic acid, glycolic acid, tartaric acid, salicylic acid, benzoic acid, and mixtures thereof.

9. The composition of claim 8, wherein the acid is selected from the group consisting of acetic acid, glycolic acid, and mixtures thereof.

10. A composition as claimed in any one of the preceding claims, wherein the pH adjusting agent is selected from sodium bicarbonate, potassium bicarbonate, lactic acid, tartaric acid or citric acid.

11. A composition according to any one of claims 1 to 10, wherein the surfactant is a soap formed from fatty acids having a carbon chain length of 8 to 18, preferably 12 to 16.

12. The composition of any one of claims 1-11, wherein the pH range of the composition is 8.0-10.

1.

13. The composition of any one of claims 1-12, wherein the composition is in solid form.

14. A method for providing an antimicrobial effect, comprising the steps of: i. applying the composition as described in any one of claims 1-13 to a surface; and ii. Cleaning the surface within 5 minutes of performing step a.

15. Use of an adduct of an amine or diamine with an acid, wherein the acid is a monocarboxylic acid or a dicarboxylic acid, in a skin cleansing composition at pH 4.0 to 10.5 comprising a surfactant for providing an antimicrobial effect.

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