A bleach composition

Abstract

The present invention relates to improving the stability of a peroxide containing bleach composition which may be used for cleaning hard surfaces like those in toilets and for cleaning fabrics. The composition also delivers antimicrobial action. It comprises a peroxide bleaching agent, a cationic surfactant and an organic acid is made more stable by inclusion of specific types of amino acids.

Description

[0001] A BLEACH COMPOSITION

[0002] Field of the Invention

[0003] The present invention relates to improving the stability of a peroxide containing bleach composition. It particularly relates to such a composition for hard surface cleaning applications including toilet cleaning as well as for fabric cleaning.

[0004] Background of the Invention

[0005] Disinfecting cleaning compositions are of great benefit to individuals, since proper use generally may reduce the number of germs and pathogens the individual is exposed to. Such compositions may for instance play an important role in reducing the occurrence and spread of infectious diseases. Disinfecting compositions containing chlorine-based bleaches are known. Such compositions are sometimes considered to be rather harsh as it may exhibit undesirable side effects, such as corrosion, malodour (like a chlorine smell) and skin irritation or skin-sensitising effects when it comes in contact with a person’s skin or mucous membrane. Therefore, many consumers prefer using compositions containing milder bleaches e.g. peroxide compounds.

[0006] Such bleach compositions are used for cleaning hard surfaces e.g. cleaning of floors, table tops, kitchen surfaces and utensils. They are also used for cleaning bathrooms and toilets. These compositions may also include certain antimicrobial agents. An antimicrobial agent like a cationic surfactant is preferred as it not only delivers the desired antimicrobial efficacy especially against gram positive bacteria but also has surfactant action which helps in cleaning the surfaces to be free of dirt and oils. Such compositions also include certain organic acids which are known to boost antimicrobial efficacy together with a peroxide compound especially against gram negative bacteria. The present applicants have filed patents published as EP2780438B1 and EP2773739B1 where such a combination along with certain other ingredients deliver improved antimicrobial efficacy.

[0007] Washing fabrics, also known as laundering or simply as laundry, makes up one of the main chores that people undertake routinely. For this, people have been relying on detergent compositions that are widely available. During day-to-day usage of fabrics, particles that may be present in the air e.g. pollen grains, dust and dirt tend to settle on a fabric. In addition, germs or microbes e.g. bacteria, fungi, spores and viruses, that are present in the air, also tend to settle on a fabric just like they tend to settle on other surfaces e.g. floors. These microbes tend to thrive when they come in to contact with substances e.g. sweat and sebum. As a result, microbial growth and / or microbial secretions, lead to problems e.g. leaving behind stains or spots which tend to affect appearance of a fabric, creation of unhygienic conditions due to thriving germs; and at times, generation of malodour. It is for reasons like these that washing of fabric becomes necessary to maintain the fabric in good condition so that it can be re-worn. Surfactants contained in a detergent composition, are primarily used for the cleaning function. To an extent, surfactants alone or along with other ingredients that may be present in a detergent composition, are able to remove germs that may be adhering to a fabric. To provide further removal of germs, antimicrobials agents like hydrogen peroxide and / or cationic surfactants may be added to these compositions.

[0008] One of the problems which the present inventors have noticed when peroxide bleaching agents are included in a composition comprising a cationic surfactant and an organic acid is that the composition is unstable on storage. Certain gases like oxygen are evolved when such liquid compositions are packed e.g. in a plastic container such that the container starts to bloat after some time. The problem can be solved by providing certain vents in the container but such a solution makes the packaging complex and expensive to manufacture.

[0009] Other solutions for stabilizing peroxide containing compositions have been proposed. LIS2019 / 0045789 (Microbio Solutions) discloses an antimicrobial composition comprising lauric arginate ethyl ester (LAE) and hydrogen peroxide and the use of this composition for disinfecting and sanitizing different types of surfaces such as food products, human skin and hard surface as well as method of stabilizing the composition by including a sequestering agent (citric salt and / or phosphate salt). The above publication does not provide for a specific solution to the bloating problem.

[0010] It is an object of the present invention to provide for an antimicrobial composition comprising a peroxide bleaching agent which in the presence of a cationic surfactant and an organic acid is more stable than has been heretofore known.

[0011] The present inventors with their deep understanding of the chemistry of such multi-ingredient compositions surprisingly found that inclusion of certain types of amino acids improve the stability of such compositions thereby mitigating the problem of bloating of the packages. Summary of the Invention

[0012] The first aspect of the present invention relates to a bleach composition comprising

[0013] (i) 0.1 to 4 wt% of a peroxide compound;

[0014] (ii) 0.1 to 3 wt% of one or more cationic surfactant;

[0015] (iii) 0.1 to 5 wt% of an organic acid or salt thereof; and

[0016] (iv) 0.05 to 2 wt% of an amino acid which has a non-polar alkyl group selected from one or more of proline, phenyl alanine, and tryptophan.

[0017] Another aspect of the present invention relates to a method of stabilizing hydrogen peroxide in a composition comprising

[0018] (i) 0.1 to 4 wt% peroxide;

[0019] (ii) 0.1 to 3 wt% of one or more cationic surfactant; and

[0020] (iii) 0.1 to 5 wt% of an organic acid, comprising the step of including therein 0.05 to 2 wt% of an amino acid which has a non-polar alkyl group selected from one or more of proline, phenyl alanine, and tryptophan.

[0021] Detailed Description of the Invention

[0022] 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%”.

[0023] Throughout this description, the term disinfection refers to reduction of the number of viable microorganisms in a given medium or on a given surface by physical or chemical means. Typically, disinfection involves the destruction or inactivation of said microorganisms. Both animate and inanimate media and surfaces are contemplated.

[0024] The term "antimicrobial" refers to a compound capable of killing, inhibiting the growth of or controlling the growth of microorganisms at a locus; antimicrobials include bactericides, fungicides and algaecides. The term "microorganism" includes, for example, fungi (such as yeast and mould), bacteria and algae.

[0025] The compositions of the present invention are preferred for non-therapeutic use, and more particularly preferred for use in cleaning surfaces, preferably wherein the surface is a hard surface and more preferably for use in cleaning applications such as cleaning kitchen, bathroom, toilet and floor surfaces. They may also be used for cleaning fabrics.

[0026] The composition comprises a peroxide compound. Preferably, the peroxide compound is one or more selected from the group consisting of hydrogen peroxide (H2O2), peracetic acid, barium peroxide (BaCh), sodium peroxide (Na2O2), tert-butylhydroperoxide, and potassium peroxydisulfate. More preferably, the peroxide selected is hydrogen peroxide. Alternatively, one or more sources of hydrogen peroxide are selected from sodium percarbonate, sodium perborate, sodium persilicate, and sodium persulphate; which release hydrogen peroxide when contacted with water, may also be used preferably in combination with an activator e.g. tetraacetylethylenediamine (TAED).

[0027] The composition preferably comprises from 0.2 to 4 wt%, more preferably from 0.5 to 4 wt%, further more preferably from 0.5 to 3 wt%, even more preferably from 0.6 to 2.5 wt% of the peroxide compound.

[0028] The composition comprises a cationic surfactant. Preferably, the cationic surfactant is a quaternary ammonium surfactant, preferably the quaternary ammonium 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.

[0029] The quaternary ammonium surfactants mentioned above, 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

[0030] The composition preferably comprises 0.1 to 3 wt%, more preferably 0.3 to 2 wt% cationic surfactant.

[0031] The composition of the invention includes an organic acid or salt thereof. The organic acid is preferably a carboxylic acid. Any carboxylic acid may be used but it is preferred that the carboxylic acid has a pKa value in the range of 1 to 5.5.

[0032] Examples of one or more carboxylic acid that may be used in the present invention include citric acid (pKa = 3.1), lactic acid (pka = 3.86), acetic acid (pKa = 4.76), malonic acid (pKa = 2.85), adipic acid (pKa = 4.43), glutaric acid (pKa = 3.76), glycolic acid (pKa = 3.83) and maleic acid (pKa = 1.9), succinic acid (pKa = 4.2), malic acid (pKa = 3.4), tartaric acid (for L+ pKa = 2.89; and for meso pKa = 3.22), hexanoic acid (pKa = 4.88), cyclohexanoic acid (pKa = 4.82), heptanoic acid (pKa = 4.8), octanoic acid (pKa = 4.89), 4-methyl octanoic acid (pKa = 5.23), nonanoic acid (pKa = 4.95), decanoic acid (pKa = 4.9), benzoic acid (pKa = 4.2) and 4-methoxy benzoic acid (pKa = 4.37).

[0033] Preferred organic acid for use in the present invention are one or more of lactic, glycolic, tartatic, malic, citric acid and benzoic acid. The most preferred acid is citric acid. The organic acid may also be present in the salt form. Alkali metal or alkaline earth metal salts are preferred, more preferably alkali metal salts of which sodium salt is most preferred. The composition comprises 0.1 to 5 %, preferably 0.5 to 3 wt% of organic acid or salt thereof.

[0034] The stabilizer in the present invention is an amino acid which has a non-polar alkyl group. It is preferred that the amino acid with a non-polar alkyl group comprises a cyclic group. Preferred amino acids which have a non-polar alkyl group which may be used are selected from one or more of proline, phenylalanine, and tryptophan, more preferably proline or phenylalanine. The amino acid is included in 0.05 to 2 wt%, preferably 0.5 to 1 .5 wt% of the composition.

[0035] The composition as per the invention preferably comprises an additional surfactant which is an amphoteric surfactant. Amphoteric surfactants which may be used include alkyl amine oxides, alkyl betaines, alkyl amidopropyl betaines, alkyl sulfobetaines (sultaines), alkyl glycinates, alkyl carboxyglycinates, alkyl amphoacetates, alkyl amphopropionates, alkylamphoglycinates, alkyl amidopropyl hydroxysultaines, acyl taurates and acyl glutamates, having alkyl radicals containing from about 8 to about 22 carbon atoms preferably selected from C12, C14, C16 ,C18 and C18: 1 , the term “alkyl” being used to include the alkyl portion of higher acyl radicals. Preferred amphoteric surfactant, when included, is selected from a C8 - C18 alkyl amine n-oxide (which is broadly referred to an amine oxide) or a betaine of which the betaine is more preferred. When an amine oxide is included it is preferably lauramine oxide. When a betaine is included it is preferably amidopropyl betaine of which cocoamidopropyl betaine is most preferred. When included the amphoteric surfactant is present in an amount ranging from 0.5 to 2%, preferably 0.5 to 1% by weight of the composition.

[0036] When the composition is formulated for use in laundry applications, it preferably comprises a nonionic surfactant. A preferred class of nonionic surfactant for use in the invention includes aliphatic C8 to C18, more preferably C12 to C15 primary linear alcohol ethoxylates with an average of from 3 to 20, more preferably from 5 to 10 moles of ethylene oxide per mole of alcohol. A preferred non-ionic surfactant is the C16 / 18 alcohol ethoxylate. When included non-ionic surfactant is present in 0.1 to 20% by weight of the composition.

[0037] The composition is generally in liquid form. It contains high amount of water. Water is generally present in 84 to 98.5%, preferably 90 to 95 % by weight of the composition.

[0038] Preferably, the composition further comprises one or more sequestrants. A preferred sequestrant is a phosphonic acid or a salt thereof. The phosphonic acid (or salt thereof) sequestrant is preferably selected from the group consisting of 1 -Hydroxyethylidene-1 ,1-diphosphonic acid (HEDP; commercially available as Dequest® 2010), Diethylenetriaminepenta(methylenephosphonic acid) (DTPMP; commercially available as Dequest® 2066), Hexamethylenediaminetetra(methylenephosphonic acid) (HDTMP), Aminotris(methylenephosphonic acid) (ATMP), Ethylenediaminetetra(methylenephosphonic acid) (EDTMP), Tetramethylenediaminetetra(methylenephosphonic acid) (TDTMP); and Phosphonobutanetricarboxylic acid (PBTC). Preferably, the sequestrant selected is HEDP.

[0039] Preferably, the composition comprises sequestrant that may be present in an amount from 0.01 to 5 wt%, more preferably from 0.05 to 4 wt%, even more preferably from 0.1 to 2.5 wt%.

[0040] The composition may optionally comprise other ingredients, such as fragrance and / or colour.

[0041] The composition preferably has a pH in the range of 2 to 5 preferably in the range of 2.5 to 4. The pH of the liquid compositions was measured using Orion Versa star (Thermo scientific) pH meter. The pH of liquid compositions as per the invention is measured using a sample of the composition (without any dilution with water) at 25 °C, using the above pH meter.

[0042] More preferably, the composition has a viscosity in the range from 1 to a maximum of 10 mPa.s at 20 S’1. Viscosity of the composition is measured using an AR 1000 Rheometer (TA instruments) using a 4 cm, 2° cone-plate geometry at 25°C. Preferably, the composition has viscosity less than 10 mPa.s @ 20 s'1.

[0043] The composition of the invention is preferably used for home care applications. A "home care product" is a product for the treatment, cleaning, caring or conditioning of the home or any of its contents. The foregoing includes, but is not limited to, compositions, products, or combinations thereof relating to or having use or application in the treatment, cleaning, cleansing, caring or conditioning of surfaces, furniture and atmosphere of the home and household contents, such as clothes, fabrics and / or cloth fibres and the manufacture of all of the foregoing products.

[0044] Preferably, the composition used in the present invention is used to clean a hard surface, more preferably wherein the hard surface is a kitchen, bathroom or floor surface. Typically, such hard surfaces are surfaces that require frequent cleaning and preferably also sanitisation and / or disinfection. Such surfaces may be found in many household or industrial environments, and may include kitchen and bathroom surfaces, tabletops, floors, walls, windows, utensils, cutlery, and crockery. Such surfaces may be made from many different materials, including for instance plastics, wood, metal, ceramics, glass, concrete, marble, and painted surfaces. The composition may be applied to the surface by any suitable means known to the skilled person. For instance, a suitable means may be pouring, dropping, spraying or wiping in case of liquid compositions.

[0045] The composition may be used as is, i.e. neat, preferably the composition is diluted with water before use. More preferably, the composition is diluted before use. For example, if applied in a diluted form, the composition is diluted with water preferably in a ratio 1 :1000, more preferably 1 :500, even more preferably 1 :200 and further more preferably 1 :100 which is substantially more diluted than a typical household cleaning composition e.g. a toilet cleaning composition, which tend to have dilutions e.g. 1 :40 when used.

[0046] Another aspect of the present invention relates to a method of cleaning and disinfecting a hard surface comprising contacting the surface with the composition of the invention preferably diluted with water in a weight ratio in the range of 1 :10 to 1 :1000, preferably 1 :30 to 1 :500 and most preferably from 1 :30 to 1 :100.

[0047] In most hard surface cleaning application, the diluted solution is applied on to the desired surface by using a brush or a mop and allowing it to dry. In certain vertical surfaces, it may be sprayed on using a hand held spray pump. In certain cases, the compositions after it is applied on to the desired surface, may be wiped off to a substantially dry condition using a dry cloth or wipe. In toilet cleaning applications, the composition is generally applied on to the toilet bowl, allowed to stay thereon for a few minutes, and then the toilet is flushed.

[0048] Another preferred embodiment of the invention relates to compositions according to the invention for use as or incorporation in industrial and / or institutional products. More preferably, this embodiment of the invention relates to a composition according to the invention which is an industrial and / or an institutional product. Industrial and institutional products are for example products being marketed under professional brands, with non-limiting examples being products for industrial, institutional, janitorial, and medical cleaning, cleaning-in-place, food services, veterinary, and agricultural products.

[0049] In another aspect, the present invention relates to a method of cleaning and disinfecting a fabric by (a) contacting the fabric with the composition of the first aspect for 5 to 60 minutes, (b) rinsing it with water; and (c) drying the fabric. Typically, a fabric is washed by contacting it with a detergent composition either in neat or diluted form, rinsing the fabric one or more times e.g. two or three times with water; and finally, drying it. In the washing step, a fabric is cleaned by mechanically agitating it using hands and / or by using suitable cleaning means e.g. a brush, in so-called hand-wash method. Alternatively, in so-called machine-wash method, a fabric is cleaned by mechanically agitations carried out by a machine. In either case, a step of soaking a fabric, in a neat or diluted detergent composition, may be carried out for a desired duration e.g. 30 to 60 minutes. The step of drying may also be carried out by using machines; or simply by exposing the fabric to air.

[0050] Yet another aspect of the present invention relates to a method of stabilizing hydrogen peroxide in a composition comprising (i) 0.1 to 4 wt% peroxide; (ii) 0.1 to 3 wt% of one or more cationic surfactant; and (iii) 0.1 to 5 wt% of an organic acid, comprising the step of including therein 0.05 to 2 wt% of an amino acid which has either a non-polar alkyl group or a positively charged alkyl group.

[0051] The invention shall now be exemplified by the following non-limiting examples.

[0052] Examples

[0053] Examples A-F, 1-2: Stability of composition as per the invention as compared to those outside the invention

[0054] The compositions as shown in Table -1 were prepared. The pH of the compositions was 2.5.

[0055] Table - 1 : Table - 2

[0056] The instability of the above compositions was measured using the following volume dispersion method:

[0057] The compositions as shown in Table-1 and Table -2 were prepared. They were placed in 125 ml sample bottles at 50°C in a hot air oven. The oxygen gas generated in the bottles as a consequence of hydrogen peroxide decomposing into water and oxygen was collected in another liquid displacement bottle through a tube. The displaced liquid was collected and measured after 2, 7, and 14 days. The amount of liquid collected represents the amount of gas formed. The cumulative amount of liquid collected was plotted against time (in days). The trend was seen to be nearly linear and the slope of the curve was calculated using linear regression and the slope is summarized in Table - 3. The higher the slope the faster is the decomposition of the hydrogen peroxide.

[0058] The bloating on storage of the various containers was measured (in number of days) using the procedure given below:

[0059] The various compositions as shown in Table-1 and -2 were prepared. The compositions were stored in a 250 ml airtight sample bottle (Domex) and kept at 50 °C in a hot air oven. As hydrogen peroxide decomposed into water and oxygen, the airtight nature of the sample bottle prevented the gas from escaping, causing the sample bottles to bloat. The bloating of the sample bottles was visually monitored every day for up to 14 days. The day on which a significant amount of bloating was observed was noted down and this is summarized in Table - 3 below. Table - 3

[0060] The data in Table - 3 above indicates that composition as per Examples 1 and 2 (as per the invention) tended to be more stable (as measured using two different methods - Quantitative as well as Qualitative) as compared to compositions outside the invention (Examples A to F).

Claims

Claims1. A bleach composition comprising(i) 0.1 to 4 wt% of a peroxide compound;(ii) 0.1 to 3 wt% of one or more cationic surfactant;(iii) 0.1 to 5 wt% of an organic acid or salt thereof; and(iv) 0.05 to 2 wt% of an amino acid which has a non-polar alkyl group selected from one or more of proline, phenyl alanine, and tryptophan.

2. A composition as claimed in claim 1 wherein the peroxide compound is hydrogen peroxide.

3. A composition as claimed in claim 1 or 2 wherein the cationic surfactant is selected from one or more of alkyl dimethyl benzylammonium chloride (ADBAC), alkyl diethyl benzylammonium chloride (ADEBAC). 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.

4. A composition as claimed in any one of the preceding claims wherein the organic acid is selected from one or more of lactic acid, glycolic acid, malic acid, tartaric acid, citric acid, and benzoic acid.

5. A composition as claimed in any one of the preceding claims comprising an amphoteric surfactant.

6. A composition as claimed in claim 5 wherein the amphoteric surfactant is selected from C8 - C18 alkyl amine n-oxide preferably lauramine oxide or a betaine preferably cocoaminopropyl betaine.

7. A method of stabilizing hydrogen peroxide in a composition comprising(i) 0.1 to 4 wt% peroxide;(ii) 0.1 to 3 wt% of one or more cationic surfactant; and(iii) 0.1 to 5 wt% of an organic acid, comprising the step of including therein 0.05 to 2 wt% of an amino acid which has a nonpolar alkyl group selected from one or more of proline, phenyl alanine, and tryptophan.

8. A method of cleaning and disinfecting a hard surface comprising a step of contacting the surface with a composition as claimed in any one of the preceding claims 1 to 7 preferably diluted with water in a weight ratio in the range of 1 :10 to 1 :1000.

9. A method of cleaning and disinfecting a fabric by (a) contacting the fabric with the composition as claimed in any one of claims 1 to 7 for 5 to 60 minutes, (b) rinsing it with water; and (c) drying the fabric.

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