ALKALINE BUILDER

Field of the invention

The invention relates to a composition for cleaning hard surfaces, more particularly for rendering toilet bowls more hygienic by controlling bacterial growth.

Background of the invention

A wide range of compositions is available for cleaning inanimate hard surfaces. Such surfaces would include bathrooms, toilet bowls and kitchens, which are made of a variety of hard materials such as enamel, ceramic, and porcelain. The types of stains usually encountered in lavatories, toilets and bathrooms include lime scale deposits, soap scum and organic soil. In addition to this, there is significant growth of bacteria in and around toilet bowls.

Compositions that are commercially available for cleaning toilets include acidic cleaners, phenyl and bleach-based cleaners. Some high-end toilet cleaning compositions include gels and pastes.

Acidic compositions are particularly effective against lime scale. Bleach-based compositions are effective against stains. However, these compositions are harsh.

WO09085049 A1 (Colgate-Palmolive) discloses a cleaning composition containing an organic acid, an ethoxylated alcohol and a hydrophilic polymer that adsorbs onto hard surfaces. US2009197786 A (Reckitt Benckiser) discloses hard surface cleaning compositions particularly adapted to clean toilets. The compositions are aqueous, thickened, acidic compositions having acid, a thickening constituent, a detersive surfactant and at least one super-wetter surfactant based on a narrow range ethoxylated alcohol nonionic surfactant having two cloud points.

WO12049202A1 (Corbellini) discloses a powdery cleaning agent containing at least one acid, at least one water-soluble carbonate and at least one biocide for cleaning flush toilets and washing machines.

US6387868B (Uno Shoyu Co. Ltd, 2002) discloses clear aqueous liquid detergents containing an alkyl benzene sulfonate surfactant, liquid sodium silicate, a polyoxyethylene alkyl or aryl ether nonionic surfactant and an alkyl ether sulfate surfactant. The silicate boosts detergency. This composition is a fabric washing composition, which is dilutable and dissolves in water without becoming cloudy over long period. The presence of nonionic and anionic surfactants provide stability. The pH of these compositions is about 7 to 8.

EP0379093A1 (Sterling Drug Inc, 1990) discloses highly alkaline, yet non-corrosive, aqueous hard surface cleaning compositions for cleaning industrial and kitchen surfaces soiled with burnt-on grease and other organic soils. Combination of alkanolamine to metasilicate in critical ratios along with certain other essential ingredients provide the desired technical effect.

In some parts of the world, people use proxy products to clean their toilets. Such proxy products include low-priced detergent powders. Alternatively, some do use bleaching powders, acids, phenyls or even leftover detergent wash-liquor. While such products do provide some degree of cleaning, they are not prepared to cater to such secondary uses. Therefore, users of such products get sub-optimal cleaning in spite of significant efforts and inconvenience. Further, the users are at risk of exposing themselves to, or coming in contact with human waste, and variety of pathogenic microbes, mainly Gram Positive and Gram Negative bacteria that thrive under unhygienic conditions.

In the absence of proper communication and knowledge of appropriate consumer products, such consumers may remain under the misbelief of clean, hygienic and germ-free toilets. Therefore, there is need for compositions, which are capable of acting against Gram Positive as well as Gram Negative bacteria within a reasonable time e.g., 10 to 30 minutes of application, without the need to alter the habits of such consumers. The compositions should be bleach-free so that consumer-awareness and product literacy need not become a concern for new users. Further, such products need to be sustainable, utilising less of non-renewable resources like synthetic surfactants.

Romanian patent R01 16484 discloses a cleaning powder comprising 70 to 90 % by weight ground dolomite, 1 to 5 % by weight soda ash, 1 to 5% sodium

tripolyphosphate, and 1 to 5% straight chain sodium salt of alkyl benzene sulfonic acid. The cleaning powder provides stain-free cleaning and is not harsh to human skin.

An abrasive cleaning formulation disclosed in Modern Chemical Specialties (Mac Nair- Dorland Company, 1950) contains 5 % by weight coconut oil soap, 2.5 % by weight sodium silicate, 3.5 % by weight soda ash and 85 % by weight abrasives.

However, these formulations are effective against either Gram Positive bacteria or Gram Negative bacteria but not necessarily both. Hard surface cleaning compositions, and especially toilet cleaning compositions, should be effective against either form of bacteria and at the same time adequately remove soil.

Summary of the invention

We have determined that a solution lies in compositions in accordance with this invention. The compositions in accordance with this invention are significantly more effective against Gram Positive as well as Gram Negative bacterium and removal of soil.

In accordance with a first aspect is disclosed a bleach-free powder composition for cleaning hard surfaces, said composition comprising:

(i) 1 to 5 % by weight non-soap anionic surfactant; and,

(ii) a non-phosphate builder having Reserve Alkalinity less than 40 ml of 0.1 N HCI in 1 % aqueous solution; and, (iii) a first abrasive having Mohs Index of 3 to 5 and a second abrasive having Mohs Index of 5.5 to 7, collectively amounting to 15 to 70 % by weight of said composition, wherein ratio between amount of said surfactant to that of said builder is 1 :0.5 to 1 :25.

The invention and all other aspects thereof will be explained in details.

Detailed description of the invention In the description, the term % by weight denotes the percentage by weight of the composition. For example, the total surfactant content of compositions in accordance with this invention is 1 to 5 % by weight, which means that 100 g of a composition contain 1 to 5 g surfactant. The term inanimate hard surfaces includes surfaces which are particularly prone to bacterial growth such as floors, walls, tiles, sinks, shower plastified curtains, wash basins, bidets and toilet bowls of Western or Indian-style toilets. On the other hand animate hard surfaces include teeth. Although the compositions in accordance with this invention are useful for toilet cleaning, the compositions could be used to clean any other inanimate hard surface.

Many people around the world face the problem of unhygienic toilets. It mostly applies to the developing and the least developed countries. Toilet bowls and the adjacent area is prone to bacterial growth. Proxy cleaning products are unable to control their growth. Therefore, the bacteria multiply quickly. Most bacteria that thrive under such conditions are pathogenic.

High-priced products may provide up to 5-log reduction in the viable bacterial count when tested according to European Suspension Test BS EN 1276. However, it is an arduous task to provide such a high level of hygiene, unless the compositions contain significant amount of acid, bleach, antibacterial agents and other active ingredients. Research indicates that at least 2-log reduction, i.e., 99 % reduction in viable count of bacteria, especially the pathogenic ones, is necessary for minimal hygiene. Gram-positive and Gram-negative bacteria thrive under unhygienic conditions. S.aureus and E.hirae are the most common Gram Positive bacteria whereas P. aeruginosa and E.coli are the most common Gram Negative type. A product of this nature is considered efficacious if it brings about at least 2-log reduction in the viable count of at least one Gram Positive bacteria and at least one Gram Negative bacteria within reasonable time e.g., 10 to 30 minutes. This is broad-spectrum antibacterial activity. Accordingly, the compositions in accordance with this invention, on contact with an inanimate hard surface comprising thereon at least one Gram positive bacteria selected from S.aureus and E.hirae and at least one Gram Negative bacteria selected from

P.aeruginosa and E.coli; provide, in accordance with BS EN 1276 protocol, at least 2-log reduction in viable count of at least one of the Gram positive bacteria and at least one of the Gram negative bacteria.

Compositions in accordance with preferred aspect of this invention provide at least 5-log reduction in the viable count of at least one of each kind when tested according to European Suspension Test BS EN 1276. The EN 1276 Standard describes a quantitative suspension test for the assessment of the bactericidal activity of chemical antiseptics and disinfectants. This test method evaluates how effectively a product causes reduction in number of viable bacterial cells of the relevant test microorganisms.

Consumers prefer hard surface cleaning powders, which are easy to handle and apply. However, some of the expensive detergent compositions contain significant amount of surfactants and it would make little sense to use such expensive products to clean toilets. However, formulating a non-bleach, non-acidic hard surface cleaning composition is a technical problem, especially if the products need to be sustainable and provide at least 2- log reduction in viable bacterial count of at least one Gram Positive bacteria and at least one Gram Negative bacteria.

The compositions in accordance with the invention are bleach-free. By bleach-free is meant that the compositions comprise (cumulatively) less than 1 % by weight conventional bleaching ingredients. Such ingredients include hypochlorites, sulphites, bisulphites, metabisulphites, isocyanurates, persulphates, percarbonates, peroxides, perborates and other bleach ingredients.

Further, it is preferred that the compositions in accordance with this invention comprise not more than 3 % by weight moisture, as moisture may affect stability.

Non-soap Anionic Surfactant

The compositions in accordance with this invention comprise 1 to 5 % by weight non- soap anionic surfactant. The total amount is significantly less than that of conventional products, therefore the composition contributes to sustainability by being lesser reliant on non-renewable resources.

The term non-soap anionic surfactant is well-known in the field of detergents and cleaning products. This term is used to distinguish non-soap anionic surfactants from their counterpart surfactants based on soaps, i.e., alkali metal salts of fatty carboxylic acids. The non-soap anionic surfactant provides basic cleaning action. It is preferred that the non-soap anionic surfactant is at least one of linear alkyi benzene sulphonate, an alkoxylated primary alcohol sulphate, a non-alkoxylated primary alcohol sulphate, an olefin sulphonate, an ester sulphonate or a secondary alcohol sulphate. It is particularly preferred that the non-soap anionic surfactant is non-alkoxylated surfactant, preferably a linear alkyi benzene sulphonate, preferably having carbon chain length of Cs-2o. Generally the counter ion for anionic surfactants is an alkali metal, typically sodium, although instead of alkali metals, other amine based counter ions can also be present. Preferred linear alkyi benzene sulphonate surfactants include sodium salt of linear alkyi benzene sulphonates with an alkyi chain length of from 8 to 15, more preferably 12 to 14. Alternatively, but less preferably, the anionic surfactant is an alkoxylated primary alcohol sulphate, generally represented by the formula RO(C2H40) _x SO3 ^" M ⁺ where R is an alkyl chain having from 10 to 22 carbon atoms, saturated or unsaturated, M is a cation which makes the compound water-soluble, especially an alkali metal, ammonium or substituted ammonium cation, and x averages from 1 to 15. Preferably R is an alkyl chain having from 12 to 16 carbon atoms, M is sodium and x averages from 1 to 9, preferably x is 1 to 7. It is particularly preferred that the alkoxylated anionic surfactant is sodium lauryl ether sulphate (SLES). It is the sodium salt of lauryl ether sulphonic acid in which the predominantly C12 lauryl group ethoxylated with an average of 1 to 5 moles of ethylene oxide units per mole. The non-alkoxylated primary alcohol sulphates are devoid of any alkoxylated groups. An example is sodium lauryl sulphate. It is particularly preferred that the non-soap anionic surfactant is linear alkyl benzene sulphonate. Alternatively, other suitable non-soap anionic surfactants, useful in the compositions in accordance with this invention are water-soluble alkali metal salts of organic sulphates having alkyl radicals containing from about 8 to about 22 carbon atoms, the term alkyl being used to include the alkyl portion of higher acyl radicals. Examples include sodium and potassium alkyl sulphates, especially those obtained by sulphating higher C8 to C18 alcohols, produced for example from tallow or coconut oil, sodium alkyl glyceryl ether sulphates, especially those ethers of the higher alcohols derived from tallow or coconut oil and synthetic alcohols derived from petroleum, ester sulphonates and the alpha-olefin sulphonates. Reference may be made to the surfactants described in "Surface Active Agents" Vol. 1 , by Schwartz & Perry, Interscience 1949, Vol. 2 by Schwartz, Perry & Berch, Interscience 1958, in the current edition of "McCutcheon's Emulsifiers and Detergents" published by Manufacturing Confectioners Company or in "Tenside-Taschenbuch", H. Stache, 2nd Edn., Carl Hauser Verlag, 1981.

It is particularly preferred that compositions in accordance with the invention comprises, cumulatively, less than 1 % by weight of surfactants, other than said non-soap anionic surfactant. Such surfactants include soap, non-ionic, cationic and zwitterionic surfactants. This is to prevent, or at least reduce to the extent possible, any unwanted interaction with other ingredients.

Non-phosphate builder

Compositions in accordance with this invention comprise a non-phosphate builder whose Reserve Alkalinity is less than 40 ml of 0.1 N HCI in 1 % aqueous solution. It is preferred that compositions in accordance with the invention comprise 1 to 15 % by weight of said builder. It is preferred that the non-phosphate builder is at least one of sodium hydroxide or sodium carbonate.

Persons skilled in the art of home care compositions, especially laundry and hard surface cleaning compositions are familiar with the meaning of the term Reserve Alkalinity. It is the amount of acid required to lower the pH to a chosen value, i.e. down to pH 8.

Without wishing to be bound by theory, it is believed that combination of the surfactant and the builder acts synergistically against Gram Positive and Gram Negative bacteria. Compositions comprising either one of them are not as effective.

The ratio between amount of the surfactant to that of the builder is 1 :0.5 to 1 :25.

Further, preferably it is in the range of 1 :1 to 1 :15. It is observed that beyond the range, the compositions are not as effective. Further, it is preferred that amount of non-phosphate builder having Reserve Alkalinity more than 40 ml of 0.1 N HCI is less than 1 % by weight. Such builders include sodium aluminate, sodium disilicate, sodium silicate and sodium metasilicate.

Abrasives

Mohs Index was developed for minerals to classify according to their hardness, from 1 (the softest) to 10 (the hardest) and has been used by mineralogists since its inception. It is preferred that the abrasive having Mohs Index of 3 or more is at least one of calcite, dolomite, sodium sulphate, feldspar, apatite, fluorite, hematite, kyanite, magnetite, orthoclase or pumice. It is particularly preferred that the abrasive is a combination of calcite and dolomite. The abrasive may form, and preferably does form, a large portion of the balance of the compositions in accordance with this invention.

The compositions in accordance with this invention comprise two different abrasives, differing in their abrasive index. The compositions comprise a first abrasive having Mohs Index of 3 to 5 and a second abrasive having Mohs Index of 5.5 to 7, collectively amounting to 15 to 70 % by weight of the composition. It is further preferred that the ratio of the amount of the first abrasive having Mohs Index of 3 to 5 to that of the a second abrasive having Mohs Index of 5.5 to 7 is in the range of 1 :0.3 to 1 :0.6. It is preferred that the first abrasive is dolomite (Mohs Index 3.5 to 4) and the second abrasive is feldspar (Mohs Index 6 to 6.5).

Further preferably, the amount of the first abrasive is 40 to 60 % by weight of the composition. Yet further preferably the amount of the second abrasive is 15 to 30 % by weight of the composition.

Salt

It is preferred that the compositions in accordance with this invention comprise an inorganic salt selected from sodium chloride, potassium chloride, sodium sulphate or potassium sulphate. It is more preferred that the salt is sodium chloride or sodium sulphate. When present, it is preferred that the amount of the salt is 5 to 15 % by weight of the composition.

Use and method in accordance with the invention In accordance with another aspect is disclosed use of a composition as claimed in claim 1 as an antibacterial toilet cleaner. It is preferred that the composition provides in accordance with BS EN 1276 protocol, at least 2-log reduction in viable count of at least one Gram positive bacteria selected from S.aureus and E.hirae and at least one Gram negative bacteria selected from P. aeruginosa and E.coli. It is further preferred that after application, said composition is allowed contact time of at least 10 to 30 minutes. In case of using the composition for cleaning toilet bowls, the said composition can be applied to the surface and spread effectively with the help of a scrubber, left for few minutes, e.g., 10 to 30 minutes, and then washed with water.

In case of using the composition for cleaning toilet bowls, the said composition can be applied to the surface and spread effectively with the help of a scrubber, left for few minutes, e.g., 10 to 30 minutes,, and then rinsed with water.

In accordance with yet another aspect is disclosed a composition of the first aspect wherein on contact with an inanimate hard surface comprising thereon at least one Gram positive bacteria selected from S.aureus and E.hirae and at least one Gram Negative bacteria selected from P. aeruginosa and E.coli, said composition provides, in accordance with BS EN 1276 protocol, at least 2-log reduction in viable count of at least one of said Gram positive bacteria and at least one of said Gram negative bacteria.

In another aspect the invention provides a method of cleaning an inanimate hard surface comprising thereon at least one Gram positive bacteria selected from S.aureus and E.hirae and at least one Gram Negative bacteria selected from P.aeruginosa and E.coli to bring about at least 2-log reduction in viable count of at least one of said Gram positive bacteria and at least one of said Gram negative bacteria in accordance with BS EN 1276 protocol, said method comprising:

(i) a step of contacting said surface with a composition in accordance with a first aspect of the invention for at least ten minutes; followed by,

(ii) washing said surface with water.

Preferably, the contact is for 15 to 30 minutes.

Compositions in accordance with the invention bring about at least 80 % reduction in toilet malodour when tested with a model malodour mix containing cresols, glycol, dimethyl disulfide and n-methyl morpholine in propylene glycol solvent. The test involves addition of the malodor mix in a container, contact with the composition for 30 minutes, followed by analysis using GCMS. The test method evaluates how effectively a product causes reduction in headspace malodor.

Optional ingredients:

The compositions of the invention may optionally comprise other ingredients, such as fragrance, colorant, foam boosting agents, odour absorbing materials, preservatives (e.g. bactericides), pH buffering agents, anti-oxidants and anti-corrosion agents.

Further, optionally, but preferably, the compositions in accordance with this invention comprise a colour-change system, which preferably comprises granular encapsulates comprising colouring agent such as a dye or pigment, which releases its colour on contact with water, which happens in-use.

Packaging The composition according to the invention could be packed in any suitable container. Preferably, the compositions are packaged in an air-tight plastic bottle with a detachable closure /pouring spout. The bottle may be rigid or deformable. Preferably, the container is clear enough so that visual cues, like the colour changing actives, if any, are visible from outside. The bottle may be provided with one or more labels, or with a shrink sleeve which is desirably at least partially transparent, for example 50 % of the area of the sleeve is transparent. The adhesive used for any transparent label should preferably not adversely affect transparency.

The invention will now be described with reference to the following non-limiting examples. Examples

Example 1 : Comparative Examples with Compositions outside the Invention

For the purpose of comparative analysis, some compositions outside the invention were prepared as tested. Details thereof are included in Table 1 . Table 1

Experiments were conducted in order to determine the efficacy of each composition of Table 1 against one Gram Positive bacteria (S.aureus) and one Gram Negative bacteria (P.aureginosa). The efficacy was determined in terms of reduction in the viable bacterial count brought about by the compositions after contact time of 15 minutes and 30 minutes.

Procedure:

The concerned test bacterium was grown overnight at 37 ^° C on a TSA (Tryptic Soya Agar) plate. The grown culture colonies were suspended again in tryptone diluent. Density of the culture was adjusted to get final count of 1.5-5.0 x 10 ⁸ cfu/ml based on McFarland standards (McFarland 1 .5 measured using bioMerieux Densomat®).

Thereafter 240 μΙ of the test solution was placed into test wells in a micro-titre plate. Equal volumes of test culture and bovine serum albumin (interfering substance) were combined for two minutes, before 60 μΙ of the mixture being added to the test solution. After a contact time of five minutes, 30 μΙ of the mixture was mixed with a neutralising solution. This solution was then serially diluted in tryptone soya broth and then spot- plated onto TSA plates. After absorption, the plates were incubated at 37 ^° C for 24 hours and the residual colonies were counted. All the experiments were done under aseptic conditions and all media were autoclaved at 15 psi pressure before use. The extent of reduction in bacterial count was calculated by taking into account the difference between initial and final cfu/ml values.

The observations are summarised in Table 2. Table 2

The data set out in Table 2 clearly indicates that none of the comparative compositions causes at least 2-log reduction in the viable count of the Gram Positive as well as the Gram Negative bacteria.

Example 2: Compositions in accordance with prior art

Comparative examples A and B (based on Romanian patent R01 16484) were tested for efficacy against S. aureus and P. aeruginosa.

Table 3

Table 4

Example 3: Compositions inside the invention Three compositions within the scope of the invention were tested as described earlier. The compositions are shown in Table 5 and the observations (recorded at the end of 30 minutes) are shown in Table 6.

Table 5

Table 6

The data in table 6 indicates that each composition led to significantly more than 2-log reduction in viable count of Gram Positive as well as Gram Negative bacteria

Example 4: Model bathroom soil removal

Comparative Examples A, B and C and Composition no. 8 were tested for efficacy of bathroom soil.

A model bathroom soil composition containing calcium stearate was sprayed on enamel tiles for uniform deposition and then baked at a certain temperature for a fixed amount of time.

5g of the composition was spread on the model bathroom soil uniformly. A pressure of 340 g/cm2 was applied on the soil through a head, covered with a cloth as an implement. The soiled plate was then scrubbed in a cleaning equipment for fixed rotations. After cleaning, the tile was rinsed under running water. The tile was weighed after drying and the % soil removal was calculated gravimetrically.

Table 7

Table 8

Model bathroom soil removal (%)

A 74

B 74

C 80

8 90