A solid disinfection composition

Abstract

The present invention relates to a solid cleaning composition in tablet form that delivers antimicrobial efficacy against both gram positive and gram negative bacteria. The composition is useful in disinfection of hard surfaces like those in toilets, kitchen sink, and dish wash machines; as well as in disinfecting fabrics. This is achieved at low concentration of cationic surfactant the efficacy of which is boosted with amino acid based surfactant in a tablet comprising an effervescent system.

Description

[0001] A SOLID DISINFECTION COMPOSITION

[0002] Field of the Invention

[0003] The present invention relates to a solid cleaning composition, more particularly a composition in tablet form that delivers antimicrobial efficacy against both gram positive and gram negative bacteria. The composition is especially useful in cleaning and disinfection of hard surfaces like those in toilets, kitchen sink, and dish wash machines. The composition may also be used to disinfect fabrics in washing machines.

[0004] Background of the Invention

[0005] Disinfecting and cleaning compositions are of great benefit to individuals, since proper use generally reduces the number of germs and pathogens the individual is exposed to. Such compositions are used for cleaning and disinfecting hard surfaces e.g. those in toilets, bathrooms, and floors at homes and public places; and in other surfaces like those in dishwash machines. Clothes and fabrics like bedsheets also require disinfection especially when used by babies and also clothes and fabrics used in hospitals. Disinfecting action can be achieved by including conventional bleaches like hypochlorite in such compositions but many consumers do not like the smell of chlorine that is generated during the use of such compositions. Compositions comprising cationic surfactants also provide efficient disinfection but they may have to be used at high concentrations. Reducing the disinfectant concentrations may be effective in killing gram negative bacteria like E. Coli but are found wanting in effectiveness against gram positive bacteria like E. hirae and S. aureus.

[0006] Solid disinfecting composition in the form of tablets is highly desirable as it is compact and can be diluted in water for a single use application by the consumer thereby providing sustainable solutions to cleaning and disinfection. The present inventors in seeking to reduce the concentration of cationic surfactant in such tablet compositions surprisingly found that with the inclusion of certain amino acid based surfactants, the efficacy of the composition in killing both gram negative as well as gram positive bacteria is boosted. They also found that quick disintegration and dissolution of the solid surfactants to disinfect the surfaces in the desired time was possible by including therein an effervescent system comprising an acidic component and a basic component. The antibacterial efficacy is also manifest by way of providing anti-malodour benefits by way of killing malodour causing bacteria. The invention is thus useful in disinfecting a surface whether it is a hard surface or a soft surface. The surface is preferably an inanimate surface. It is thus an object of the present invention to provide for a composition in tablet form that can disinfect surfaces with low amounts of the cationic surfactant active.

[0007] It is another object of the present invention to provide for such a composition that ensures desired kill of both gram negative as well as gram positive bacteria.

[0008] Summary of the Invention

[0009] The first aspect of the present invention relates to a solid disinfection composition comprising: a) 0.05 to 1 wt% a quaternary ammonium surfactant; b) 0.05 to 3 wt% an amino acid surfactant; and c) an effervescent system comprising an acidic component and a basic component; wherein the weight ratio of the quaternary ammonium surfactant to amino acid surfactant is in the range of 2:1 to 1 :20, preferably 1 :1 to 1 :10; wherein the quaternary ammonium surfactant is selected from one or more of alkyl dimethyl benzylammonium chloride (ADBAC), bis Cs-Cis alkyl di methyl quaternary ammonium chloride preferably didecyl dimethyl ammonium chloride (DDAC), cetyl trimethyl ammonium chloride (CTAC), cetyl pyridinium chloride (CPC), cetrimonium bromide, benzethonium chloride (BZE); and dimethyldioctadecylammonium chloride.

[0010] Another aspect of the present invention relates to a method of disinfecting a surface comprising the steps of

[0011] (i) adding the solid surface cleaning composition of the invention into water to form a wash liquor;

[0012] (ii) letting the surface be in contact the wash liquor for a desired period of time;

[0013] (iii) optionally rinsing the surface with water; and

[0014] (iv) optionally drying the surface.

[0015] Detailed Description of the Invention

[0016] For the avoidance of doubt, any feature of one aspect of the present invention may be utilised in any other aspect of the invention. The word "comprising" is intended to mean "including" but not necessarily "consisting of” or "composed of". Thus, the term "comprising" is meant not to be limiting to any subsequently stated elements, but rather to optionally also encompass nonspecified elements of major or minor functional importance. In other words, the listed steps or options need not be exhaustive. Whenever the words "including" or "having" are used, these terms are meant to be equivalent to "comprising" as defined above. It is noted that the examples given in the description below are intended to clarify the invention and are not intended to limit the invention to those examples per se. Except in the examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts of material or conditions of reaction, physical properties of materials and / or use are to be understood as modified by the word "about". Unless specified otherwise, numerical ranges expressed in the format "x to y" are understood to include x and y. When for a specific feature multiple preferred ranges are described in the format "x to y", it is understood that all ranges combining the different endpoints are also contemplated. Unless specified otherwise, amounts as used herein are expressed in percentage by weight based on total weight of the composition and is abbreviated as “wt%”.

[0017] The composition of the invention includes a quaternary ammonium surfactant. The surfactant is selected from one or more of alkyl dimethyl benzylammonium chloride (ADBAC) which is also known as benzalkonium chloride (BKC), bis (C8-C18) alkyl di methyl quaternary ammonium chloride preferably didecyl dimethyl ammonium chloride (DDAC), cetyl trimethyl ammonium chloride (CTAC), cetyl pyridinium chloride (CPC), cetrimonium bromide, benzethonium chloride (BZE); and dimethyldioctadecylammonium chloride. Preferred aspect of the invention provides for the cationic surfactant to be chosen from one or more of BKC or DDAC, preferably BKC. It is preferred that the quaternary ammonium surfactant is not a softener e.g. dioctadecyl dimethyl ammonium chloride.

[0018] They are available as a single quaternary ammonium compound, as well as mixtures of two or more different quaternary ammonium compounds e.g. under trademarks BARDAC™, BARQUAT® and HYAMINE® (all by Lonza); and BTC® (by Stepan). Quaternary ammonium compounds available as a single quaternary ammonium compound include didecyl dimethyl ammonium chloride (available as BARDAC™ 2250 R and BTC® 1010, both 50% active; and BARDAC™ 2280 R and BTC® 1010-80, both 80% active), alkyl dimethyl benzyl ammonium chloride (available as BARQUAT® MB-50, BARQUAT® MX-50, BARQUAT® QJ-50, HYAMINE® 3500, BTC® 50, BTC® 50E, BTC® 65, BTC® 776, BTC® 824, BTC® 835; each 50% active; and the same is available as BARQUAT® MB-80, BARQUAT® MX-80, HYAMINE® 3500-80, BTC® 8248, BTC® 8358; each 80% active

[0019] The quaternary ammonium surfactant is included in at least 0.05%, preferably at least 0.06%, more preferably at least 0.08% by weight of the composition. The quaternary ammonium surfactant is included in at most 1.0%, more preferably at most 0.9%, more preferably at most 0.8% by weight of the composition. Useful weight% ranges of the quaternary ammonium surfactant for inclusion in the composition of the invention are 0.05 to 0.9%, preferably 0.05 to 0.8% by weight of the composition.

[0020] Amino acid surfactants are surfactants that may be produced by biotechnological and chemical methods using amino acids and (vegetable) oils or fat. Because amino acids and vegetable oils or fats are renewable sources, the class of amino acid surfactants are a suitable material in detergent compositions that are made from renewable sources. The combination of a polar amino acid and non-polar oil or fat chain provides molecules with high surface activity. Due to the wide variety of amino acids (and peptide) structures and the variety in the chain length of the oily or fat group, the properties of amino acid surfactant also vary, allowing for specific amino acid surfactants for specific purposes.

[0021] The amino acid surfactant is preferably selected from one or more of glutamates, sarcosinates, glycinates and alaninates preferably one or both of glutamate and sarcosinate. The fatty chain is preferably a C6 - C16 fatty acid chain, more preferably C10 to C16, the most preferred fatty acid chains are lauroyl and cocoyl chains. The amino acid is preferably selected from one or both of disodium lauroyl glutamate and sodium lauroyl sarcosinate.

[0022] Since the oily or fatty chain is typically derived from natural sources, the fatty acids and alcohols they are made of are not always a pure single chain length ingredient. By Cx-Cy is generally meant that at least 50% of the alkyl chains comprise of between x and y carbon atoms, preferably at least 60%, more preferably at least 70%, still more preferably at least 80%, even more preferably at least 90%, yet more preferably at least 95%, or even at least 98%, or ideally at least 99% of the alkyl chains comprise of between x and y carbon atoms.

[0023] The amino acid surfactant is present in the composition in a concentration of 0.05 to 3% based on the total weight of the composition. Preferably the amino acid surfactant is present in a concentration of at least 0.1 wt%, more preferably at least 0.2 wt%, still more preferably at least 0.3 wt%, but preferably not more than 2.5 wt%, more preferably not more than 2.0 wt% and typically not more than 1.5% wt, based on the total weight of the composition. The weight ratio of the quaternary ammonium surfactant to amino acid surfactant in the composition of the invention is in the range of 2:1 to 1 :20, preferably 1 :1 to 1 :10, most preferably from 1 :1 to 1 :5.

[0024] It is preferred that the composition comprises minimal amount of anionic surfactants other than the amino acid surfactant claimed. By minimal amount is meant that anionic surfactant other than the amino acid surfactant claimed is present in less than 5wt%, preferably less than 2 wt%, further more preferably less than 1 wt% and ideally absent from the composition.

[0025] The composition comprises an effervescent system comprising an acidic component and a basic component. The acidic component is preferably selected from an organic acid, for example a carboxylic acid, organic acid salts, organic acid anhydrides, inorganic acids, inorganic acid salts, and mixtures thereof. Preferably, the organic acid, and related salts and anhydrides are selected from carboxylic acids having up to 8 carbon atoms. Preferably, the acid component is an organic acid, an acid anhydride, sodium dihydrogen phosphate, disodium dihydrogen pyrophosphate, acid citrate salts, sodium acid sulphite and mixtures thereof, preferably wherein the acid source is an organic acid selected from citric acid, malic acid, tartaric acid, fumaric acid, sulfamic acid, oxalic acid, maleic acid, gluconic acid, succinic acid, salicylic acid, adipic acid and mixtures thereof, more preferably wherein the acid is one or both of citric acid and sulfamic acid.

[0026] The basic component is preferably selected from carbonates, bicarbonates, sequicarbonates and mixtures thereof. More preferably, the carbonate component is preferably an alkali metal carbonate, preferably sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, sodium glycine carbonate and mixtures thereof.

[0027] The acidic component is present in the effervescent system in an amount preferably ranging from 20 to 80 wt%, more preferably from 30 to 80 wt% and even more preferably ranging from 40 to 70 wt%. The basic component is preferably included in 25 to 50%, preferably 30 to 40% by weight of the composition. The acidic and basic components are included in amounts to achieve rapid, complete solubility of the unit dose. Consequently, the molar ratio of acid component to basic component should be approximately within a range of from about 1 .0:2.0 to about 1 .0:4.0.

[0028] The composition of the invention is preferably in unit dose form. Preferably, the combination of acidic and basic components should comprise 50 wt% of the unit dose. More preferably, the acidic and basic components comprise at least 75 wt% of the unit dose and most preferably, at least 80 wt% of the unit dose.

[0029] The composition of the invention may further comprise a lubricant, which may act as a processing aid to make the composition less sticky and allow for improved manufacturing. Suitable lubricant includes stearates such as magnesium stearate and calcium stearate, sodium benzoate, mineral oil, silicates, algenic acid, polyethylene glycols, dipropylene glycol or mixtures thereof.

[0030] Preferably the composition comprises from 0.01 to 10% by weight of the lubricant, more preferably from 0.1 to 8%, even more preferably from 0.5 to 5%, based on total weight of the composition.

[0031] The composition of the present invention may comprise other ingredients which are common in the art to enhance physical properties and performance in addition to those materials described above. These ingredients include colorant, perfume, polymers, corrosion inhibitors, flush regulators, adhesion inhibitors, pH regulators, enzymes, preservatives, sequestrants, builders or mixtures thereof. Such ingredients typically and collectively make up less than 20% by weight of the composition, preferably from 0 to 15% by weight, most preferably from 0.01 to 10% by weight of the composition, including all ranges subsumed therein.

[0032] The composition may be colored using any conventional means of coloring in the area of surface cleaning especially toilet cleaning but preferably the colorant is a polymeric colorant, or pigment dispersion colorant. Preferably the composition comprises 0 to 3% by weight of the colorant, more preferably 0.01 to 2%.

[0033] Perfume or fragrance may be present in an amount of 0 to 7% by weight of the composition, preferably 0.05 to 6% and more preferably 0.1 to 5%.

[0034] Polymers, such as acrylic polymers, can suitably be incorporated in the composition to reduce formation of lime scale and soil re-deposition.

[0035] Enzymes that may be applied in the composition include proteases, lipases, amylases, hydrolases and / or cellulases. The unit dose form is a solid. Preferably, the unit-dose is a concentrate, capsule, tablet, lozenge or block. Preferably the unit dose is a tablet, lozenge or block. Most preferably it is in the form of a tablet. When in the form of a tablet it has a weight of from 1 to 200 grams, preferably from 5 to 100 grams.

[0036] It is not preferred that the unit dose composition is wrapped in a water soluble film. It was found that the presence of water soluble film can lead to residues during dissolution in water which is not preferred in some cases such as in a toilet bowl. The ball-shaped solid surface cleaning composition is preferably packaged in a blister pack or a multi-dose container which is preferably equipped with a child-safe locking mechanism.

[0037] Formation / shaping of the cleaning composition into various solid form may be achieved by using known methods and equipment, such as those in the field of detergent product manufacturing, machine dishwash tablet manufacturing, or toilet cleaning block manufacturing. If the ingredients of the composition are available in liquid form, they may be dehydrated by any means known to those skilled in the art for removing liquid from a composition. Preferably the amount of water in the composition is from 0 to 1 % by weight of the composition, more preferably from 0 to 0.5%.

[0038] Preferably, the solid composition of the present invention can be made by combining the ingredients together to provide a homogeneous mixture and compressing the mixture into a desired solid using electric or hydraulic tabletting machine. Compression pressure is typically from 50 MPa to 1000 MPa. The solid composition of the present invention may also be made by combining the ingredients together to provide a homogeneous mixture, extruding the mixture into an extruded strand, and cutting / shaping the extruded strand into a desired solid.

[0039] The composition of the invention may be used in cleaning and disinfection of any hard surface like those in homes and outside and also for disinfection of soft surfaces like those of fabrics. The solid unit dose composition of the invention is most preferred for use in surfaces generally submerged in water e.g. toilet bowls, kitchen sinks, dishwash machines, and laundry washing machine. The solid unit dose composition may be dropped into the toilet bowl such that the composition effervesces, and the foam substantially fills up the bowl providing for enhanced disinfection along most of the height of the walls of the bowl. The toilet may be flushed after a desired amount of time.

[0040] Similarly dishes and utensils left in the kitchen sink and filled up with water may be provided with the composition of the invention by dropping a tablet into the sink. The utensils may be left therein for a desired period of time to ensure disinfection before it is rinsed free of food residue and the disinfection actives. Dishes washed in a dishwash machine as well as the machines walls and internals along with the machine dishwash filter may similarly be disinfected.

[0041] Heavily soiled fabrics like baby wear, bedsheets and clothes used in hospitals, nursing homes and paediatric wards require extra disinfection. The present invention provides a mild (odour free and safe on skin) yet effective disinfection of such fabric. The tablet may be dropped into the washing machine after it is filled with the fabric and water and held for a desired amount of time for the disinfection to be complete. Thereafter the fabrics may be subjected to the standard washing machine routine. Clothes washed by hand may similarly be contacted with the composition in pre-wash bucket and given sufficient period of soak time before it is washed in the standard procedure.

[0042] Thus, as a general method, the invention provides for a method of disinfecting a surface comprising the steps of

[0043] (i) adding the composition of the invention into water to form a wash liquor;

[0044] (ii) letting the surface be in contact the wash liquor for a desired period of time;

[0045] (iii) optionally rinsing the surface with water; and

[0046] (iv) optionally drying the surface.

[0047] The invention will now be illustrated with the help of the following non-limiting examples.

[0048] Examples

[0049] Examples A-D, 1-6: Effect of concentration of various surfactant combinations on the antibacterial efficacy

[0050] Compositions in the form of tablets were prepared as shown in Table -1 below:

[0051] Table -1 :

[0052] In the table above

[0053] Lutensol: refers to Lutensol AT 25 which is Alcohol Ethoxylate Type A-25 EO

[0054] SLS: is sodium lauryl sulphate.

[0055] BKC: is benzalkonium chloride which is Alkyl(C12-C14) dimethyl benzyl ammonium chloride sold under the name Barquat MS-100.

[0056] Sarcosinate: is Sodium Lauroyl Sarcosinate

[0057] Glutamate: is Disodium Cocoyl I Lauroyl Glutamate

[0058] The above compositions were tested for antibacterial efficacy against one gram negative bacteria E.coli and one gram positive bacteria S. aureus using the following procedure.

[0059] The suspension test used for the evaluation is according to the common test protocol of EN1276. The bacterial cultures as used have a bacterial count of 108bacteria per ml. In this test 8ml of formulation was used together with 1 ml of bacterial culture and 1ml of BSA solution. The BSA solution is at a concentration of 0.3% to mimic a “dirty” surface condition. After mixing 1 ml of culture with 8 ml of formulation and 1 ml of BSA solution, the bacterial count is diluted 10 times, thus resulting in a bacterial count at the start of the experiment of 107bacteria per ml. The formulation and bacteria were kept in contact for 30 minutes and then neutralized (to quench the efficacy of the actives and stop its action against bacteria). With respect to a water control, the bacterial log reduction delivered by the composition is calculated and summarized in the table- 2 below. The examples are carried out at room temperature of 23 °C. Target organism:

[0060] Staphylococcus aureus ATCC 6538

[0061] Escherichia coli ATCC 10536

[0062] The data on log kill of the respective bacteria is given in table - 2. A log kill of more than 5.0 is considered sufficiently effective. Table - 2:

[0063] The data in the table -2 above indicates that using a concentration of 2.0% BKC (Example - A) it is possible to get desired antibacterial efficacy. However as the concentration of BKC is reduced to 1 % and 0.5% (Examples B, C) the desired antibacterial kill is not obtained when SLS is the cosurfactant. However when SLS is replaced with the amino acid surfactant as per the invention (Examples 1-6) antibacterial efficacy is boosted and this is seen for BKC concentrations as low as 0.1%. It is also clear from Example D where no BKC is used, the amino acid alone delivers low efficacy.

[0064] Examples E-H and 7,8: Effect of ratio of BKC to amino acid surfactant at different pH

[0065] Model experiments were carried out with just the two surfactants (BKC and sarcosinate) as shown in Table - 3 below at two different pH (7.0 and 10.0). The procedure used to measure the antibacterial efficacy against S. hominis is the same as used for the preceding set of examples. Target organism:

[0066] Staphylococcus hominis ATCC 27844. S. hominis is a gram positive organism.

[0067] Table -3:

[0068] NG in the above table refers to no visible growth of bacteria.

[0069] The data in the table above indicates that at high weight ratios (1 :25 and 1 :50) of BKC to amino acid surfactant (examples G and H) the efficacy drops as compared to examples within the invention (Example 7 and 8) where the desired weight ratio is maintained. This trend is observed for both pH 7.0 and 10.0.

[0070] Examples 3, J: Effect of inclusion of effervescent system

[0071] Compositions as shown in Table - 4 were tested for antibacterial efficacy. The compositions are Example - 3 and a similar example (Example - J) without the effervescent system. The experiment was done to measure efficacy at 10 minutes and 30 minutes. The procedure used was the same as in the preceding experiments except that the contact times was 10 minutes and 30 minutes as indicated in the Table 4 below.

[0072] The data is summarised in table -4

[0073] Table - 4 The data in Table - 4 above indicates that inclusion of the effervescence system ensures faster antibacterial kill.

Claims

Claims1. A solid disinfection composition comprising: a) 0.05 to 1 wt% a quaternary ammonium surfactant; b) 0.05 to 3 wt% an amino acid surfactant; and c) an effervescent system comprising an acidic component and a basic component;Wherein the weight ratio of the quaternary ammonium surfactant to amino acid surfactant is in the range of 2:1 to 1 :20, preferably 1 :1 to 1 :10; wherein the quaternary ammonium surfactant is selected from one or more of alkyl dimethyl benzylammonium chloride (ADBAC), bis Cs-Cis alkyl di methyl quaternary ammonium chloride preferably didecyl dimethyl ammonium chloride (DDAC), cetyl trimethyl ammonium chloride (CTAC), cetyl pyridinium chloride (CPC), cetrimonium bromide, benzethonium chloride (BZE); and dimethyldioctadecylammonium chloride.

2. A composition as claimed in claim 1 , wherein amino acid surfactant is selected from one or more of glutamates, sarcosinates, glycinates, and alaninates.

3. A composition as claimed in claim 2 wherein the amino acid surfactant is one or both of glutamate and sarcosinate.

4. A composition as claimed in any one of the preceding claims, wherein the acidic component is selected from one or more of an organic acid, an acid anhydride, sodium dihydrogen phosphate, disodium dihydrogen pyrophosphate, acid citrate salts, and sodium acid sulphite.

5. A composition as claimed in claim 4 wherein the acidic component is selected from one or more of citric acid, malic acid, tartaric acid, fumaric acid, sulfamic acid, oxalic acid, maleic acid, gluconic acid, succinic acid, salicylic acid, and adipic acid; preferably one or both of citric acid and sulphamic acid.

6. A composition as claimed in any one of the preceding claims wherein the acidic component is included in 20 to 80% by weight of the composition.

7. A composition as claimed in any one of the preceding claims wherein the basic component is a carbonate source selected from alkali metal carbonate, preferably one or more of sodiumcarbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, and sodium glycine carbonate.

8. A composition as claimed in any one of the preceding claims wherein the basic component is included in 25 to 50% by weight of the composition.

9. A composition as claimed in any one of the preceding claims in the form of a powder, a granulated particle or a shaped solid, preferably a shaped solid, more preferably in tablet form.

10. A composition as claimed in claim 9, wherein the tablet has a weight of from 1 to 200 grams, preferably from 5 to 100 grams.

11. A method of disinfecting a surface comprising the steps of(i) adding the composition of the invention into water to form a wash liquor;(ii) letting the surface be in contact the wash liquor for a desired period of time;(iii) optionally rinsing the surface with water; and(iv) optionally drying the surface.

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