Background to the Invention Many formulations have been proposed in the literature for so-called'descaler'compositions. These generally comprise sufficient acid to give a low pH and may comprise a thickening agent so as to cause the composition to cling to and be retained on sloping surfaces, such as the inside of toilet bowls. As described in more detail below, known thickeners include both ethoxylated and unethoxylated tertiary amines, either alone or in combination with a hydrotrope. Known acids for use in such compositions include sulphamic and phosphoric acids.

It is advantageous that such compositions should be antimicrobial and that they should exhibit this antimicrobial effect against a broad range of micro- organisms. In order to achieve this various bactericides have been proposed as additives to these compositions.

GB 1443244 relates to acid cleaners and descalers which comprise as a thickening agent an ethoxylated tertiary amine of which ETHOMEEN S12 (N, N-dihydroxyethyl-oleylamine) is given as an example. The composition also comprises

acids which are selected from mineral acids and acid salts of strong inorganic acids such as sulphamic acid.

Bacteriocides are an additional, optional component.

FR 2459830 discloses compositions which comprise non- ethoxylated and ethoxylated amines together with sulphamic acid. The composition may also comprise disinfectants.

WO 95/27768 discloses cleaning compositions, particularly intended for painted and plastic surfaces comprising ethoxylated C10-C18 aliphatic amines containing 3-8 ethoxy units (preferably 4-6) and C6-C10 carboxylic acids and/or organic or inorganic chelating agents. The compositions are not disclosed to have disinfecting properties.

AU-A-57022/86 relates to cleaning systems which comprise a mixture of sulphamic and phosphoric acids and an acid stable surfactant. Bacteriocides are optional and formalin is disclosed as a bacteriocide which improves the antibacterial effect of the acids.

EP-B-0276501 discloses thickened aqueous cleaning compositions which comprise 0.1-50% wt of a weak acid having a pK >2 (of which sulphamic is given as an example), 0.1-20% wt of an amine which can include 2% of oleyl- bis- (2-hydroxyethyl)-amine and 0.01%-5% wt hydrotrope (sodium xylenesulphonate is given as an example).

Disinfecting agents are optional.

EP-A-0314232 relates to compositions which undergo a viscosity increase on dilution and discloses that thickened liquid detergent compositions can be prepared with an amine oxide, amine (such as ETHOMEEN S12), betaine or

quaternary ammonium compound and hydrotrope (sodium xylene- sulphonate). It is stated in the specification that amine oxides and quaternary ammonium compounds are known to have biocidal properties and that further microbiocides including organic peracids are optional. These compositions can be of acidic, neutral or alkaline pH.

From the above it can be seen that while certain thickening surfactants such as quaternary ammonium compounds and amine oxides are known to have antibacterial properties it has been commonplace to suggest the addition of further antimicrobial components to descaling compositions where antimicrobial effects are desired in addition to descaling.

Brief Description of the Invention We have determined that compositions which comprise both alkoxylated aliphatic amines and sulphamic acid show an improved antimicrobial effect. It is believed that this is due to a synergistic interaction of these components and that the effect is obtained irrespective of the presence (i. e. also in the absence) of other antimicrobial species.

We have also determined that excellent scale removal and disinfection is obtained with compositions which comprise: a) an alkoxylated aliphatic amine, b) sulphamic acid, and, c) a source of peroxygen species.

Detailed Description of the Invention According to a first aspect of the present invention there is provided the use of 0.01-15% wt of an alkoxylated aliphatic amine having an aliphatic hydrocarbon group of 8- 20 carbon atoms and 1-8 units of alkoxylation per mole of amine to improve the antimicrobial effectiveness of an acidic, antimicrobial composition comprising 0.01-15% wt of a sulphamic acid.

According to a second aspect of the present invention there is provided an acidic, antimicrobial composition comprising: a) 0.01-15% wt of an alkoxylated aliphatic amine with 8-20 carbon atoms and 1-8 units of alkoxylation; b) 0.01-15% wt of a sulphamic acid, and c) a source of peroxygen species.

According to a third aspect of the present invention there is provided a method of disinfecting surfaces which comprises the step of treating the surface with an acidic, antimicrobial composition comprising: a) 0.01-15% wt of an alkoxylated aliphatic amine with 8-20 carbon atoms and 1-8 units of alkoxylation and b) 0.01-15% wt of sulphamic acid.

Amines: Typically, the alkoxylated aliphatic amine is a tertiary amine of the general formula: H (A) X-N (R)- (A) yH

wherein R is an alkyl or alkenyl group comprising 8-20 carbon atoms, A is an ethoxy or propoxy group and x and y may be the same or different and are integers from 1-4.

Preferably R has 8-18, more preferably 10-18 carbon atoms; x and y are preferably 1-3, more preferably 1 or 2. The preferred materials are ethoxylated amines wherein A is -OCH2CH2-. In further preferred embodiments of the invention R is C14-C18 alkyl or alkenyl and is e. g. derived from oleic, palmitic or myristic acid.

Suitable ethoxylated aliphatic amines are e. g. : -N, N-di (hydroxyethyl)-oleylamine which is available from AKZO under the trademark ETHOMEEN S12; -C12-C18 aliphatic amine ethoxylates containing 2 or 3 ethoxy groups, wherein between 20 and 40% of the aliphatic groups are unsaturated (i. e. R = C12-C18 20- 40% unsaturated, x=1 and y = 1 or 2). An example of such material is ETHOMEEN BTB/12, which is also available from AKZO and is a mixture of N, N-di (hydroxyethyl) aliphatic amine derived from fully hardened tallow and the oleyl derivative in a 65/35 ratio. Such a mixed material can be prepared by synthesis using combined starting materials mixed in the appropriate ratio, or obtained by mixing commercially available materials such as ETHOMEEN HT12 and ETHOMEEN S12T in the desired ratio.

-C12-C16 alkyl amines containing 2 or (even more preferably) 3 ethoxy groups (i. e. R = C12-C16 alkyl, x=1 and y = 1 or preferably 2).

As can be seen from the above, particularly suitable ethoxylated amines or mixtures of such amines are those wherein the aliphatic group is predominantly (for more than

50%) derived from C16 and C18 fatty acids and wherein (average) x+y is 2-3 Preferred levels of the alkoxylated aliphatic amine are 1-10% wt on product with levels of 2-6% wt on product being particularly preferred.

Acids: Typical levels of sulphamic acid (i. e. amino-sulphonic acid) range from 1-10% wt on product with levels of 2-6% on product being particularly preferred.

Peroxygen Sources: Where present, typical sources of peroxygen species include one or more of hydrogen peroxide, peracetic acid and/or other organic or inorganic peroxygen sources. Hydrogen peroxide is a preferred source of peroxygen species.

Typical levels of hydrogen peroxide range from 1-10% wt on product with levels of 3-8% being particularly preferred.

Surfactants: Preferred compositions according to the invention additionally comprise nonionic surfactant and/or hydrotrope.

Suitable nonionic detergent active compounds (surfactants) can be broadly described as compounds produced by the

condensation of alkylene oxide groups, which are hydrophilic in nature, with an organic hydrophobic compound which may be aliphatic or alkyl aromatic in nature. The length of the hydrophilic polyoxyalkylene radical which is condensed with any particular hydrophobic group can be readily adjusted to yield a water-soluble compound having the desired degree of balance between hydrophilic and hydrophobic elements. Suitable nonionic surfactants include alkoxylated alcohols and alkyl phenols, preferably ethoxylated alcohols The preferred ethoxylated alcohols are of the general formula: Rl- (OCH2CH2) m-OH wherein R1 is straight or branched C8-C18 alkyl or hydroxyalkyl (preferably alkyl) and m is, on average, 1-14.

Ethoxylated alcohols suitable for use in the present invention include the LIAL series available in the marketplace from DAC, such as LIAL 111.10EO [TM]. Typical levels of nonionic surfactant in products according to the present invention range from 0-5%.

Suitable hydrotropes include lower aliphatic alcohols, especially ethanol, urea and/or alkylaryl-sulphonates such as salts of, particularly alkali metal salts of toluene-, cumene-or xylene-sulphonate.

The preferred hydrotropes are alkylaryl-sulphonates, most preferably sodium cumene-sulphonate. A suitable material is ELTESOL SC 40 (TM Albright and Wilson). Typical levels of hydrotrope range from 0.05-2% wt on product.

In particularly preferred embodiments of the invention the alkoxylated aliphatic amine is present together with an anionic surfactant at levels of these materials are such that they interact so as to thicken the composition Preferably, formulations comprising the alkylaryl sulphonates are formulated at a pH below 2, more preferably below 1.5, even more preferably below 1. Without wishing to limit the invention by reference to any theory of operation, it is believed that at such a low pH, the ethoxylated amine behaves as a cationic surfactant and interacts with the alkylaryl sulphonate to form a water- insoluble gel which deposits as a monolayer on surfaces.

It is believed that this monolayer lowers the surface energy of the surface and retards or prevents the deposition of further limescale.

The preferred mole ratio of the ethoxylated amine and the anionic surfactant is 3-3.5, more preferably 3.25-3.5.

The preferred viscosity of the cleaning compositions according to the present invention is between 50 mPas and 1000 mPas when measured at 11.7 sec-1 shear and at 25 Celcius using Haake RV2 rotoviscometer and an MV1 bob.

Particularly preferred compositions according to the present invention comprise: a) 1-10% wt, preferably 3-5% wt sulphamic acid, b) 1-10% wt, preferably 2-5% wt ethoxylated amine, c) 0-5% wt, preferably 0.05-1% wt, nonionic surfactant, d) 0.05-2% wt, preferably 0.4-l. 1% wt, anionic surfactant hydrotrope

e) 1-10% wt, preferably 4-6% wt, hydrogen peroxide Minors: While the combination of the surfactants in the compositions of the invention provide a thickening effect it is possible to add other thickeners. Gums, particularly xanthan gums are suitable thickeners. Preferred xanthan gums are the Kelzan (RTM) series (available from Kelco Corp). If present, typical levels of xanthan gum range from 0.05-lwt%. The resulting viscosity of the composition, as measured on a Haake RV2 rotoviscometer (RTM) is preferably in the range 10-200 mPas at 20 reciprocal seconds shear and 25°C, using an MV1 bob. More preferably the viscosity is 10-100 mPas under the conditions mentioned above.

Metal ion sequestrants such as ethylenediamine tetra- acetate, amino-poly-phosphonates (such as those in the DEQUESTTM range ex. Monsanto) and phosphates and a wide variety of other poly-functional organic acids and salts, can also optionally be employed. Preferred metal ion complexing agents are selected from dipicolinic acid, ethylenediamine tetra-acetic acid (EDTA) and its salts, hydroxyethylidene-diphosphonic acid (Dequest 2010), ethylenediamine-tetra (methylene-phosphonic acid) (Dequest 2040), diethylenetriamine-penta (methylene-phosphonic acid) (Dequest 2060).

Optional, minor components also include those typically found in cleaning compositions and are selected from opacifiers, colours perfumes and fluorescers.

Preferred levels of perfume range from 0.05-2% wt. Acid stable perfumes are available from a variety of sources.

A particularly preferred composition according to the present invention comprises: ETHOMEEN BTB/12 ex AKZO 2-5% Ethoxylated amine SULPHAMICACID 4% HYDROGEN 5% PEROXIDE LIAL 111.10EO ex DAC 0. 1% Nonionic surfactant ELTESOL SC40 ex Albright 0.4-1.1% * Sodium Cumene- Sulphonate BRILLIANT BLUE 9 ex WJE 0. 0021% CI 307047/colour PERFUME ex IFF 0. 12% Othello 39 DEQUEST 2066 ex Monsanto 0-0.3% WATER to 100%

*variable to adjust viscosity Typical products having the above formulation made with 3.0% wt of the amine and around 0.56% wt of the SCS are clear, have a specific gravity of 1.040 g/ml, an initial viscosity at 106 sec-1 (at 25°C) of 120mPas, an initial viscosity at 11.7 sec-1 (at 25°C) of 300mPas and pH 0.9 (at 25°C).

In order that the present invention may be further understood it will be illustrated hereafter with reference to the following non-limiting examples.

Examples: Example 1: Antibacterial Synergy Suspension tests were carried out with compositions of the invention and comparative compositions at typical in-use dilutions (2%) of a composition according to the invention.

The following bacterial strains were used in the suspension tests.

Pseudomonas aeruginosa ATCC 15442 Staphylococcus aureus ATCC 6538 Enterococcus faecium DVG 8582 Proteus mirablis ATCC 14153 Antibacterial activity was determined according to EST (DD177: 1988) and performed under soil conditions of 0.03% wt bovine serum albumen (BSA) at 19.5 Celcius. Total viable count was determined after a five minute and a 30 minute contact time using solutions as listed below and water of standard hardness for controls. Log reduction relative to water were determined. Viable organisms were determines by culturing on Nutrient or Tryptone-soya agar for 48 hours at 37°C. Log decimal reductions were determined from the viable counts. Table 1 below gives the results for 5 and 30 minutes contact time.

Concentrations in the assay, which were representative of those encountered in a toilet bowl after use of the product according to the invention, were as follows: Sulphamic acid: 0.08% wt Hydrogen peroxide: 0.10% wt Amine ethoxylate: 0.06% wt Ethomeen S/12 [TM] TABLE 1 (log kill).

Suspension test results showing mean log kill, cfu/ml.

CK = Complete Kill NSK = No Significant Kill Organism S. aureus E. faecium P. P. mirabilis aerugi- nosa Soil 0.03% BSA 0. 03% BSA 0.03% BSA 0. 03% BSA F w, =s _, »- i, 6 ; ContacftT ;05i3i0i50° 503D ;;50 30 ; l in min ; Sulphamic 0.00 0.05 1.95 0.96 2.45 0.00 acid NSK NSK NSK NSK NSK Sulphamic 1.62 2.15 0.00 0.14 1.74 0.93 2.36 1. 64 acid + NSK NSK NSK NSK NSK peroxide I543.991.015.014.3 4.856.954.36sulphamic 3. acid + NSK CK peroxide + amine ethoxylate sulphamic 3.29 3.91 1.56 5.01 2.69 4.85 6.95 4.36 acid + amine NSK CK ethoxylate

Initial Counts: Staphylococcus aureus ATCC 6538 6.99 Enterococcus faecium DVG 8582 6.99 Pseudomonas aeruginosa ATCC 15442 4.36 Proteus mirabilis ATCC 14153 4.95 A neutraliser of Tween (TM) Peptone, volume of 49ml was used. Therefore where counts are zero this is equivalent to <50cfu/ml or log 50 = 1.70 survivors. From this table it can be seen that the combination of sulphamic acid and amine ethoxylate has improved bacteriocidal properties over sulphamic acid per se, against this broad range of bacteria. In the table figures above 3, indicating disinfectant behaviour are printed in bold.

In particular, it can be seen that sulphamic acid alone (first example) has poor antimicrobial properties which are not significantly improved by the presence of hydrogen peroxide (compare first two examples), but that the compositions which comprise both sulphamic acid and the amine ethoxylate (compare bottom two examples) have antimicrobial properties which are almost as good as those of systems which further comprise hydrogen peroxide (bottom example).