GB2498996A

GB2498996A - Lime scale removing composition

Info

Publication number: GB2498996A
Application number: GB1201810.7A
Authority: GB
Inventors: Matthew Stuart Clark; Tony Griffin; Matthew Stevenson; Amandine Sbardella; Dean HILL
Original assignee: Jeyes Group Ltd
Current assignee: Jeyes Group Ltd
Priority date: 2012-02-02
Filing date: 2012-02-02
Publication date: 2013-08-07
Anticipated expiration: 2032-02-02
Also published as: GB2498996B; GB201201810D0

Abstract

A composition, preferably for treating limescale, comprising: Water; Formic acid; Sulphamic acid and/or citric acid; a thickener; a surfactant and a surface-modifying polymer, wherein the composition has a viscosity of at least 4000 cps, preferably 4500-9000 cps. The tichener may be a polysaccharide, preferably xanthan gum. The surfactant may be a non-ionic surfactant including alkoxylated alcohol, and a cationic surfactant including a di or trialkyl amine ethoxylate salt. Methods of preparing and using such a composition are claimed.

Description

1

Lime scale Remover

INTRODUCTION

The present invention relates to a composition for treatment of lime scale, to a 5 method of making the composition and to methods of treating lime scale using the composition. The invention is also concerned with kits comprising the composition as well as a brush.

BACKGROUND

10 Lime scaling is the deposition of inorganic salts on a surface or object. The most common inorganic salt present in lime scale is CaC03. Soluble calcium bicarbonate (Ca(HC03)2) in mains water is converted to insoluble CaC03 when the water is heated. The CaC03 precipitates out of the water forming limescale. Once formed, the inorganic salt, i.e. the scale, tends not to redissolve.

15 Visible lime scale deposits are aesthetically displeasing and moreover can impact on the performance of devices. Lime scale deposited on a shower head, for example, can impact on its spray pattern. Similarly lime scale deposited on valves can prevent them from fully functioning.

Furthermore, the formation of lime scale frequently occurs in combination with 20 other types of soils, such as soap scum or grease, and can lead to the formation of limescale-soil mixture deposits (lime scale-containing soils). Such deposits are unsightly and may be considered unhygenic.

A number of lime scale removing compositions are of course already available on the market, e.g. Limelite, Cillit Bang and Viakal. Limelite and Cillit Bang each 25 comprise an acid system (Limelite comprises sulfamic acid, citric acid and formic acid and Cillit Bang comprises sulfamic acid and formic acid) in combination with a range of surfactants.

The lime scale removing compositions currently on sale are generally in the form of liquids. Thus the compositions are typically used by applying the lime scale 30 removing liquid to the surface or object to be treated by pouring or squeezing it from a bottle or via a spray system. After leaving the liquid to react with the lime scale for a period of time, the surface or object is then rinsed. This method works best for surfaces and objects that are generally planar since the liquid generally remains in contact with the surface, disperses across it and thereby reacts with its entirety.

2

When non-planar surfaces or objects are treated with lime scale removing liquids, however, the liquid tends to run off of the surface. Thus, for example, when lime scale removing liquid is applied to the top of a curved tap, the liquid tends to run round around its surface and then drip or run off. This means that the contact time 5 between the lime scale present on the tap and the lime scale removing liquid is limited. This problem is exacerbated when the lime scale is present in a hard to reach location, e.g. on the underside of a tap. It is usually impossible to spray lime scale removing liquid onto such a surface since spray bottles are not generally designed to work upside down. Similarly it is difficult to squeeze or pour liquid lime scale removing 10 composition onto such a surface. Users therefore tend to soak a cloth in the liquid and wrap this around the tap. As a result, however, a significant proportion of the lime scale removing liquid is simply soaked into the cloth, rather than reacted with the lime scale present on the tap.

A need therefore exists for improved lime scale removing compositions that can 15 be used to effectively remove lime scale, particularly from non-planar surfaces and/or difficult to reach surfaces. Such compositions should dissolve lime scale quickly and preferably leave the surface and/or object treated with an aesthetically pleasing appearance, e.g. with a shine. Obviously such compositions should not cause any damage to the surfaces and objects treated.

20

SUMMARY OF INVENTION

Viewed from a first aspect, the present invention provides a composition for treatment of lime scale comprising:

(i) water;

25 (ii) formic acid;

(iii) sulfamic acid and/or citric acid;

(iv) a thickener;

(v) a surfactant; and

(vi) a surface-modifying polymer,

30 wherein said composition has a viscosity of at least 4000 cps.

A preferred composition of the invention is in the form of a gel.

Viewed from a further aspect, the present invention provides a method of making a composition as hereinbefore defined comprising mixing (i) water; (ii) formic acid; (iii) sulfamic acid and/or citric acid; (iv) a thickener; (v) a surfactant; (vi) a polymer 35 and optionally (vii) Ci-8 alcohol.

3

Viewed from a further aspect, the present invention provides the use of a composition as hereinbefore defined for the treatment of lime scale.

Viewed from a further aspect, the present invention provides a method of treating lime scale on a surface comprising:

5 (a) applying a composition as hereinbefore defined to said surface or object;

(b) leaving said composition to react with said lime scale on said surface or object;

(c) optionally mechanically agitating said surface; and

(d) rinsing said surface or said object.

Viewed from a further aspect, the present invention provides a kit for the 10 treatment of limescale comprising:

a composition as hereinbefore defined; and a brush.

DETAILED DESCRIPTION OF INVENTION 15 As used herein the term lime scale is intended to encompass any precipitate which may be formed in a water system, especially a domestic water system. In domestic water systems, typical examples of lime scale include carbonate salts of group I and group II metals, e.g. CaC03 and MgC03. The composition of the present invention is particularly effective in treating lime scale comprising CaC03. 20 Lime scale may be categorised as "thin lime scale". By "thin lime scale" is meant lime scale that has been formed over a period of less than 8 weeks.

Lime scale may also be categorised as "hard lime scale". By "hard lime scale" is meant lime scale that has been formed over a period of more than 8 weeks.

As used herein the term %wt refers to the percentage by weight of the entire 25 composition unless otherwise specified.

As used herein the term gel refers to a cross-linked system which exhibits no flow when in the steady state.

As used herein the term thickener refers to a compound that increases the viscosity of the composition.

30 As used herein the term viscosity refers to the resistance of a fluid to deformation by shear stress. The viscosities of the compositions described herein are measured using a Viscometer according to the method described in detail in the examples.

The compositions of the present invention have a viscosity of at least 4000 cps. 35 At this viscosity, the compositions of the invention are non-drip, i.e. the composition

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can be applied to a surface and it will stick to the surface rather than run or drip off it. Thus an advantage of the composition of the present invention is that it can be applied to a non-planar surface and it will remain thereon. When it is applied to a planar surface it can be spread across the surface using an applicator, e.g. a brush. It has 5 been advantageously found that this enables the composition to contact lime scale present along the edges and at corners of surfaces and thus to effectively remove lime scale from the entire surface. This contrasts with the performance of liquid lime scale removing compositions.

Preferred compositions of the invention have a viscosity of 4500-9000 cps, still 10 more preferably 5000 to 7500 cps and still more preferably 5500 to 6500 cps. Whilst the composition should have a sufficiently high viscosity to render it non-drip, it should not be too high otherwise it may difficult to spread over a surface. The compositions of the invention exhibit an ideal balance of properties in this respect.

Preferred compositions of the invention are in the form of a gel. Preferred gels 15 of the present invention are hydrogels.

Preferred compositions of the present invention comprise 70-85 %wt, more preferably 75 to 82 %wt and still more preferably 76 to 79 %wt water. The water may be tap water, distilled water or deionised water. Tap water is preferred, particularly soft tap water. Soft tap water is generally substantially free of any undesirable impurities 20 such as organics or inorganics, especially mineral salts, which are present in hard water and which may undesirably interfere with the operation of the compositions of the invention.

The compositions of the present invention comprise a thickener in order to provide it with a desired viscosity. Preferably the thickener is a polysaccharide. 25 Suitable polysaccharides for use in the compositions include substituted cellulose materials such as carboxymethylcellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxymethyl cellulose, succinoglycan gum, xanthan gum, gellan gum, guar gum, locust bean gum and tragacanth gum. Derivatives of any of the afore-going and/or mixtures of the afore-going may also be used. 30 Preferred compositions of the invention comprise a polysaccharide selected from the group consisting of succinoglycan gum, xanthan gum, gellan gum, guar gum, locust bean gum, tragacanth gum and derivatives thereof. More preferably the compositions of the present invention comprise a polysaccharide selected from the group consisting of xanthan gum, gellan gum, guar gum and derivatives thereof. Most 35 preferably, the compositions comprise xanthan gum or derivatives thereof.

Polysaccharides for use in the present invention are commercially available. Suitable xanthan gum and derivatives thereof are, for example, commercially available from Rhodia under the trade name Rhodopol extra2 clear.

Typically, the compositions of the present invention may comprise 0.1 % wt to 5 5 % wt by weight of the total composition of a thickener (e.g. polysaccharide), more preferably 0.75 % wt to 2.2 % wt and most preferably 1.0 % wt to 2.0 %wt.

An important feature of the compositions of the present invention is the acids present therein. Preferred compositions of the present invention have a pH of 0.75 to 3.0, still more preferably 0.9 to 2.0 and still more preferably 1.0 to 1.3. The acidic pH of 10 the composition of the invention ensures that it treats lime scale. The acids present in the composition react with the lime scale. Generally the CaC03 reacts with the acid to produce a soluble calcium salt, carbon dioxide and water. The successful treatment of lime scale with the composition of the invention can often be determined by the observation of bubbles at the treatment site. This is due to the release of C02 in the 15 reaction. The compositions of the invention preferably treat lime scale, e.g. as evidenced by the release of C02, within 10 minutes, more preferably within 5 minutes and yet more preferably within 2 minutes of its application to the lime scale.

The compositions of the present invention comprise formic acid, i.e. methanoic acid. Preferably the formic acid incorporated into the compositions of the invention has 20 a concentration of 80 to 95 % wt and still more preferably about 90 % wt. Formic acid, e.g. 90 %wt formic acid for use in the compositions of the invention is commercially available from a range of suppliers, e.g. Univar.

Preferred compositions of the invention comprise 2 to 20 %wt formic acid, still more preferably 3 to 15 %wt formic acid and yet more preferably 4 to 14 %wt formic 25 acid. Thus when formic acid is used in the form of a 90 % wt aqueous solution, the amount of formic acid added to the composition is preferably in the range 3 to 20 %wt and still more preferably 4 to 15 %wt.

The compositions of the invention additionally comprise at least one further acid selected from sulfamic acid and citric acid. The compositions may comprise all three 30 acids, i.e. formic acid, sulfamic acid and citric acid. Preferably, however, the composition comprises formic acid and a second acid selected from sulfamic acid and citric acid. It has been surprisingly found that these combinations of acids are particularly effective in combination. Particularly preferred compositions of the invention display a synergistic effect in the performance of its acids. Thus in preferred 35 compositions, the effect of the combination of acids on lime scale exceeds the additive

6

effect of the use of each of the acids individually. This is highly advantageous since it means that the overall amount of acid, which is corrosive, present in the compositions of the invention can be reduced.

Preferred compositions of the invention comprise 5 to 15 %wt sulfamic acid, still 5 more preferably 8 to 12 %wt sulfamic acid and yet more preferably 9 to 10 % wt sulfamic acid. Sulfamic acid is commercially available for a range of suppliers, e.g. Univar.

More preferred compositions of the invention comprise citric acid. Preferred compositions of the invention comprise 2.5 to 15 %wt citric acid, still more preferably 3 10 to 12 %wt citric acid and yet more preferably about 5 or 9.75 % wt citric acid. Citric acid is commercially available for a range of suppliers, e.g. Univar. Preferably the citric acid is anhydrous.

Some particularly preferred combinations of acids are listed below. These combinations of acids have been found to provide the greatest level of synergy in lime 15 scale removal.

5 to 15% wt sulfamic acid and 3.5 to 7.5 % wt formic acid, still more preferably 8 to 12% wt sulfamic acid and 4 to 7 % wt formic acid

2.5 to 7.5 % wt citric acid and 10 to 20 % wt formic acid, still more preferably 3 to 6.5 % wt citric acid and 11 to 15 % wt formic acid 20 The compositions of the present invention comprise at least one surfactant.

The surfactant may be anionic, cationic or non-ionic. Preferred compositions of the invention comprise at least two surfactants, e.g. two surfactants. Particularly preferred compositions of the present invention comprise a non-ionic surfactant and a cationic surfactant.

25 The presence of a non-ionic surfactant in the compositions of the present invention has been found to enhance their cleaning performance, e.g. in soap scum removal. As a result, when compositions comprising a non-ionic surfactant are used to clean a surface they tend to leave a shine that is aesthetically pleasing. Such compositions tend to be highly rated in consumer tests.

30 A particularly preferred class of non-ionic surfactant for use in the compositions of the present invention are alkoxylated alcohols. Such surfactants can be readily made by condensation reactions that are well known in the art. Additionally a huge range of alkoxylated alcohol surfactants, and especially ethoxylated alcohol surfactants, are commercially available.

7

Preferred alkoxylated alcohols for use in the compositions of the invention are of formula (I):

R0(CH2CH20)e(CH2CH2CH20)pH (I)

5

where R is a C2.24 alkyl or alkylene, preferably alkyl, chain; and e and p represent the average degree of ethoxylation and propoxylation respectively and are each, independently from 0 to 24, wherein the sum of e and p is at least 2.

In preferred compounds of formula (I) R is C4.18, more preferably C6-i2. 10 Preferably R is straight chain alkyl.

In further preferred compounds of formula (I) p is 0.

In yet further preferred compounds of formula (I) e is 1 to 20, preferably 5 to 15, e.g. 6 to 12.

A particularly preferred class of cationic surfactants for use in the compositions 15 of the present invention are quaternary ammonium surfactants, particularly di or trialkyl amine ethoxylate salts. Preferably the alkyl groups present in these surfactants contain between 1 and 22 carbon atoms. The alkyl groups may be saturated or unsaturated but are preferably saturated. The average degree of ethoxylation is preferably 2 to 20. The degree of propoxylation is preferably 0 to 20. Such cationic surfactants are 20 commercially available.

Preferred quaternary ammonium surfactants for use in the compositions of the invention are of formula (II):

R1R2R3N+(CH2CH20)nH X" II

25

wherein each of R1 and R2 is independently a Ci_24 alkyl or alkylene, preferably alkyl, chain;

R3 is (CH2CH20)mH or a Ci_24 alkyl or alkylene, preferably alkyl, chain;

n is between 2 and 24, preferably 3 to 16, still more preferably 3 to 12; 30 m is between 2 and 24, preferably 3 to 16, still more preferably 3 to 12; and X is a counter ion.

In preferred compounds of formula (II) R1 is C4-i8 alkyl, more preferably C6-16 alkyl, still more preferably C12_i8 alkyl. Preferably R1 is straight chained alkyl.

In further preferred compounds of formula (II) R2 is Ci-6 alkyl, more preferably 35 Ci-3 alkyl, e.g. methyl, ethyl or propyl. Particularly preferably R2 is methyl.

8

In further preferred compounds of formula (II) R3 is (CH2CH20)mH. When R3 is C-,-24 alkyl, however, it is preferably alkyl, more preferably C^ alkyl, e.g. methyl, ethyl or propyl, especially methyl.

In compounds of formula (II) X may be any counter ion, e.g. a halide such as CI"

5 or Br".

A preferred surfactant blend comprising a non-ionic surfactant and a cationic surfactant is commercially available from Chemlink under the name Link 706. It is indicated by its supplier to be an aqueous surfactant blend comprising 60-70 % wt of ethoxylated C7.21 alcohol and 20-30 %wt of a chloride salt of a quaternary coco alkyl 10 methyl amine ethoxylate. Compositions of the invention comprising Link 706 are observed to have excellent cleaning characteristics giving surfaces a shiny appearance.

The compositions of the present invention preferably comprise 0.10 to 1.00 %wt total surfactant, more preferably 0.15 to 0.75 %wt total surfactant and still more 15 preferably 0.20 to 0.50 %wt total surfactant. Particularly preferred compositions comprise 0.06 to 0.7 %wt of non-ionic surfactant, more preferably 0.09 %wt to 0.50 %wt and still more preferably 0.12 to 0.5 %wt. Further particularly preferred compositions comprise 0.02 to 0.3 %wt of cationic surfactant, more preferably 0.03 %wt to 0.2 %wt and still more preferably 0.04 to 0.15 %wt.

20 While not wishing to be bound by the following theory it is believed that the combined cationic and non-ionic surfactants present in Link 706 provide excellent penetration of lime scale, especially hard lime scale present on surfaces exposed to elevated temperatures, e.g. hot water taps. It is hypothesised that the combination of the non-ionic surfactant and the cationic surfactant present in the composition is 25 especially effective in removing soap scum present in lime scale. More specifically rapid penetration and removal behaviour is observed.

The compositions of the present invention comprise a surface-modifying polymer. Preferred surface-modifying polymers impart a shine on the surface or object treated. Preferred polymers comprise charged side chains, still more preferably 30 positively charged side chains. Particularly preferred surface-modifying polymers comprise side chains comprising an ammonium salt. Whilst not wishing to be bound by theory it is hypothesised that such polymers impart hydrophilic and easy cleaning properties to the surface to which they are applied.

The compositions of the present invention preferably comprise a surface-35 modifying polymer formed from a trimethyl-[2-(2-methyl-1-oxoprop-2-

9

enoxy)ethyl]ammonium salt, e.g. trimethyl-[2-(2-methyl-1-oxoprop-2-enoxy)ethyl]ammonium chloride. Although homopolymers formed from trimethyl-[2-(2-methyl-1-oxoprop-2-enoxy)ethyl]ammonium salt could be used, copolymers of trimethyl-[2-(2-methyl-1-oxoprop-2-enoxy)ethyl]ammonium salt are preferred. 5 Particularly preferred surface-modifying polymers for use in the compositions of the present invention are also formed from a C3.6 alkenoic acid, e.g. of formula CH2=CH(CH2)aCOOH where a is an integer between 0 and 3. Especially preferred surface-modifying polymers are formed from 2-propenoic acid.

Further preferred surface-modifying polymers for use in the compositions of the 10 present invention are also formed from a C3_6 alkenamide, e.g. of formula CH2=CH(CH2)bCONH2 where b is an integer between 0 and 3. Especially preferred surface-modifying polymers are formed from 2-propenamide.

A preferred surface-modifying polymer for use in the compositions of the invention is commercially available under the tradename Flexipel SR-80 from 15 Chemlink. It is supplied as a 10-30% wt dispersion in water. Its suppliers indicate that it is a polymer formed from trimethyl-[2-(2-methyl-1-oxoprop-2-enoxy)ethyl]ammonium chloride, 2-propenoic acid and 2-propenamide.

The compositions of the present invention preferably comprise 0.001 to 0.15 %wt of surface-modifying polymer, more preferably 0.005 to 0.10 %wt and still more 20 preferably 0.01 to 0.03 %wt.

The compositions of the present invention may comprise a variety of optional ingredients depending on, e.g. the surface or object to be treated. Preferred compositions often further a comprise a Ci.8 alcohol, especially a diol. Representative examples of suitable Ci.8 alcohols that may be present in the compositions of the 25 invention include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol and tripropylene glycol. Propylene glycol is particularly preferred.

The compositions of the present invention preferably comprise 0.5 to 5 %wt Ci_8 alcohol, more preferably 1 to 4 %wt Ci_8 alcohol and still more preferably 2 to 3.5 % wt Ci-8 alcohol.

30 One particularly preferred composition of the invention comprises:

(i) 70 to 85 % wt water;

(ii) 3 to 7.5 %wt formic acid;

(iii) 5 to 15 %wt sulfamic acid;

(iv) 0.75 to 2.2 %wt thickener, preferably xanthan gum or a derivative thereof;

35 (v) 0.10 to 1.00 %wt surfactant, preferably a blend of non-ionic and cationic surfactant;

10

(vi) 0.005 to 0.15 %wt surface-modifying polymer, preferably surface-modifying polymer which comprises side chains comprising an ammonium salt; and

(vii) 1.0 to 4.0 %wt C-i-8 alcohol, preferably propylene glycol.

Other particularly preferred compositions of the invention comprise: 5 (i) 70 to 85 % wt water;

(ii) 10 to 20 % wt formic acid;

(iii) 2.5 to 7.5% wt citric acid;

(iv) 0.75 to 2.2 %wt thickener, preferably xanthan gum or a derivative thereof;

(v) 0.10 to 1.00 %wt surfactant, preferably a blend of non-ionic and cationic surfactant; 10 (vi) 0.005 to 0.15 %wt surface-modifying polymer, preferably surface-modifying polymer which comprises side chains comprising an ammonium salt; and (vii) 1.0 to 4.0 %wt Ci-s alcohol, preferably propylene glycol.

A still further preferred composition of the invention comprises:

(i) 75 to 80 % wt water;

15 (ii) 12 to 15 % wt formic acid;

(iii) 3 to 7 % wt citric acid;

(iv) 1.0 to 2.2 %wt thickener, preferably xanthan gum or a derivative thereof;

(v) 0.15 to 0.5 %wt surfactant, preferably a blend of non-ionic and cationic surfactant;

(vi) 0.01 to 0.03 %wt surface-modifying polymer, preferably surface-modifying polymer 20 which comprises side chains comprising ammonium salt; and

(vii) 2.0 to 3.5 %wt alcohol, preferably propylene glycol.

Other optional ingredients that may be present in the compositions of the invention include perfume, dye, pigments, organic solvents, chelating agents, radical scavengers, buffers, bactericides, hydrotropes, colorants, stabilizers, enzymes, soil 25 suspenders, brighteners, anti dusting agents and dispersants. The skilled man will readily be able to determine the necessary amount of each of these ingredients. Generally compositions of the present invention will comprise 0-5 wt% of such ingredients, preferably less than 3 %wt of such ingredients and still more preferably less than 2 %wt.

30 The compositions of the invention may be prepared using methods conventional in the art. Typically the composition is prepared by mixing (i) water; (ii) formic acid; (iii) sulfamic acid and/or citric acid; (iv) thickener; (v) surfactant; (vi) surface-modifying polymer and optionally (vii) Ci-8 alcohol using a stirrer. The composition may be prepared by mixing the ingredients in any order and the skilled 35 man will be able to determine suitable procedures. One preferred method, however,

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comprises: mixing (i) water; (iv) thickener and if present (vii) Ci-8 alcohol to form a first mixture; mixing (ii) formic acid, (iii) sulfamic acid and/or citric acid and (v) surfactant to form a second mixture; mixing said first and second mixtures and adding thereto (vi) surface-modifying polymer.

5 The compositions of the present invention are preferably provided as a ready to use composition. It can then be directly applied to the surface or object to be treated, e.g. sinks, taps, shower heads, shower screens or trays, drains etc. The compositions may be packaged in any suitable container particularly bottles or pots. Bottles or pots having relatively wide necks are particularly preferred to enable a brush to be inserted 10 into the container.

Preferably the composition of the present invention is supplied along with a brush. Thus kits comprising a composition of the present invention and a brush form another aspect of the present invention. A preferred kit further comprises instructions for use of the composition and brush.

15 The present invention further encompasses a method of treating lime scale on a surface or object, preferably removing lime scale from said surface or said object. The process of the invention comprises the steps of: applying a composition as hereinbefore defined to the surface or object; leaving said composition to react with the lime scale on the surface or object; optionally mechanically agitating said surface, and 20 then rinsing said surface or said object.

The surface or object treated using the compositions of the invention encompasses any surface prone to lime scale formation. They include surfaces typically found in and around houses such as bathrooms and kitchens, e.g., floors, walls, tiles, windows, sinks, showers, shower doors, trays and curtains, wash basins, 25 toilets, dishes, fixtures and fittings etc. The surfaces may be made of different materials, e.g. bricks, vinyl, no-wax vinyl, linoleum, melamine, Formica, glass, plastic, metals and chrome.

Objects treated using the compositions of the invention include water-taps or parts thereof, water-valves, shower heads and shower fittings and parts thereof. 30 Preferred surfaces and objects treated with the compositions of the present invention have a non-planar surface and/or are hard to reach. The compositions of the present invention are particularly advantageous for the treatment of non-planar surfaces because its gel form enables the composition to remain in place once applied. Additionally the relatively high viscosity of the composition facilitates its application 35 using a brush that can reach into small spaces and cavities prone to lime scale build

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up. Since the composition is in gel form it remains in place at the site of its delivery. This beneficially means that entire surfaces including its edges and corners can be effectively treated. It also means that small areas of lime scale can effectively be spot treated without application of the composition to the remainder of the surface. 5 A preferred method of treating lime scale comprises the step of applying a composition of the present invention onto the surface or object. Preferably the application is carried out with a brush.

Further preferred methods of the invention comprise leaving the composition on the surface or object to react with the lime scale, preferably for 1 to 45 minutes, more 10 preferably 5 to 30 minutes, still more preferably 10 to 25 minutes, e.g. 15 to 20 minutes.

Optionally the surface or object may be mechanically agitated during the leaving step or after it is completed. For instance, the surface or object may be wiped with an appropriate instrument, e.g. a sponge, cloth or brush. In preferred processes, 15 the surface or object is wiped after the leaving step is complete. Preferably the surface or object is then rinsed.

Preferably rinsing is with water. Preferably the resulting surface has a shiny appearance.

The invention will now be described in the following non-limiting examples and 20 Figures wherein:

Figures 1 and 2 show the performance of a composition of the invention, Viakal and Limelite against thin lime scale;

Figures 3 and 4 show the performance of a composition of the invention, Viakal and Limelite against hard lime scale;

25 Figure 5 shows the results of the performance of a composition of the invention and Viakal in a drop test;

Figure 6 shows the results of the performance of a composition of the invention and Limelite in a drop test; and

Figure 7 shows the performance of a composition of the invention, Viakal and Limelite 30 in a tap test.

EXAMPLES

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Determination methods

The viscosities of the compositions described herein were measured using a Brookfield viscometer, with spindle 5 at 20 rpm.

pH was determined using a Mettler Toledo pH probe which was inserted into the sample composition. The composition was stirred until the pH reading was constant.

Compositions tested

A) Preferred composition of the invention, referred to as T2

B) Viakal

C) Limelite

These are described in the tables below. All % are by weight of composition. Viakal and Limelite are commercially available products.

A

Role

% w/w added

% w/w final composition

Water

75.90%

77.48

Rhodopol extra2 clear

Thickener

1.25%

1.25

Propylene glycol

0,-8 alcohol

2.50%

2.50

Citric acid

Acid

5.00%

5.00

Formic acid, 90%

Acid

15.00%

13.5

Link 706

Surfactant

0.25%

0.25

Flexipel SR-80 (10-30% polymer in water)

Surface-modifying polymer

0.10%

0.01-0.03, -0.02

Viscosity (cps)

5775

PH

1.25

• Rhodopol extra2 clear is a polysaccharide, specifically a modified xanthan gum.

• Link 706 is an aqueous surfactant blend comprising 60-70 % wt of ethoxylated C7-21 alcohol and 20-30 %wt of a chloride salt of a quaternary coco alkyl methyl amine ethoxylate

• Flexipel SR-80 is a 10-30% wt dispersion in water of a polymer formed from trimethyl-[2-(2-methyl-1 -oxoprop-2-enoxy)ethyl]ammonium chloride, 2-propenoic acid and 2-propenamide.

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B

C

Water Perfume

Butylphenyl methylpropional Benzyl salicylate Hexyl cinnamal <5 % non ionic surfactants

Water, Sulfamic acid, Urea Citric acid, Sodium cumene sulfonate C9-11 alcohol ethoxylate, Alcohol denat, Formic acid, Xanthan gum Styrene/acrylates copolymer,

Perfume

Methyl alcohol, Glyoxal, lodopropynyl Butylcarbamate, CI 61585

Viscosity (cps)

110

470

PH

1.37

0.67

The composition of the invention was prepared as follows:

1) mixing water, Rhodopol extra2 clear and propylene glycol to form a first mixture; 5 2) mixing formic acid, citric acid and Link 706 to form a second mixture;

3) mixing said first and second mixtures and adding Flexipel SR-80 thereto.

Tile test

Two types of lime scale were grown on enamelled ceramic tiles: thin & hard lime scale. 10 The tiles were immersed in an open top water bath for 4-16 weeks (<8 weeks for thin lime scale and > 8 weeks for hard lime scale) which was heated to -70 °C. Fresh hard water was added to the bath regularly to maintain water level and keep up a high concentration of hardness minerals. A few drops of washing up liquid was added to form soap scum. The tiles were then dried.

15

A thin lime scale and a hard lime scale tile were each used in the experiment described below.

1. Each tile was separated into sixteen 3cm2 squares with red electrical tape. Blu tack was placed around those squares enclosing Limelite and Viakal compositions to

20 prevent them leaking into adjacent squares. This was not necessary with the composition of the invention as it is sufficiently viscous not to flow.

2. Each 3x3 cm square was used as shown below.

15

Control

No treatment

T2 Formula

No treatment

Limelite

No treatment

Viakal

No treatment

Control

5 min.

T2 Formula

5 min.

Limelite

5 min.

Viakal

5 min.

Control

10 min.

T2 Formula

10 min.

Limelite

10 min.

Viakal

10 min.

Control

20 min.

T2 Formula

20 min.

Limelite

20 min.

Viakal

20 in.

3. A picture was taken before the experiment started (Fig. 1)

4. 0.3 g of each composition was applied to the relevant square of the tile using a 5 pipette and then spread to cover the whole square with an applicator brush. The timer was started when the composition touched the tile

5. After the time interval elapsed the composition was removed by dabbing with dry kitchen roll 10 times and then by dabbing with damp kitchen roll 10 times

6. The tiles were then left in the drying cupboard to dry and a picture was taken 10 afterwards (Fig. 2).

The results from testing on thin lime scale are shown in Figures 1 and 2. Figure 1 shows the tile before testing started and Figure 2 shows the tile after the completion of testing and drying. The results show the following:

15 After 5 minutes - the composition of the invention shows significantly better lime scale removal than both Limelite and Viakal

After 10 minutes - the composition of the invention shows significantly better lime scale removal than Viakal and more even removal of lime scale across the entire surface of the square than Limelite 20 After 15 minutes - the composition of the invention shows better lime scale removal across the entire surface of the square than both of Viakal and Limelite. The composition of the invention works all the way to the edges and corners of the square whereas the activity of Viakal and Limelite is focussed on the centre of the squares.

25 The results from testing on hard lime scale are shown in Figures 3 and 4. Figure 3

16

shows the tile before testing started and Figure 4 shows the tile after the completion of testing and drying. The results show the following:

After 5 minutes - the composition of the invention shows comparable performance to Limelite and significantly better performance than Viakal 5 After each of 10 and 20 minutes - the composition of the invention shows significantly better lime scale removal than both Limelite and Viakal. The composition of the invention removes the lime scale much more evenly across the entire surface of the square than either of Limelite or Viakal.

10 Overall the composition of the invention performs better than both of Limelite and Viakal on "light" & "hard" limescale. The composition of the invention starts to react with lime scale within 5 minutes of its application.

Drop test

15 This test shows how effective the composition of the invention per se is compared to those commercially available. In other words this test does not take into account manual removal of lime scale (e.g. via scrubbing).

1 tile was used in this test as described below:

20 1. A lime scale covered tile was separated into 4 quarters with red electrical tape with each being designated a specific time as shown below.

5 min.

10 min.

15 min.

20 min.

2. A picture was taken before the experiment was started (see Fig 5) 25 3. 1 drop of Viakal was added to the tile and it was then spread to cover a ~1.5 cm diameter. A timer was started

4. 1 drop of the composition of the invention was added adjacent to the Viakal drop. It was spread to a diameter of -1.5 cm diameter and another timer was started. A circle was drawn around the drops with a permanent marker.

17

5. After the allotted time period, the compositions were removed by dabbing 10 times with a dry piece of kitchen roll followed by dabbing 10 times with a damp piece

6. The sample areas were then treated with slowly running water from a tap to remove any other traces of composition

5 7. The tile was placed in the drying cupboard until dry, then another picture was taken (see Fig 5).

The results are shown in Figure 5 wherein Col is composition of the invention. The results show the following:

10 After 5 minutes - the composition of the invention is significantly better than Viakal at lime scale removal. The composition of the invention shows a fairly even spread of action from the centre to the edge of the circle. Viakal's removal capability seems to be more towards the centre.

After 10 minutes - the composition of the invention still shows much more significant 15 lime scale removal than Viakal.

After 15 minutes - the composition of the invention is significantly better than Viakal. The composition of the invention shows excellent lime scale removal from the centre to the edge of the spot whilst Viakal only seems to remove some lime scale from the centre of the spot

20 After 20 minutes - again the composition of the invention shows significantly more lime scale removal than Viakal. The latter only removed lime scale close to the centre of the spot.

The test above was repeated, with the exception that Limelite rather than Viakal was 25 used. Moreover the drops of compositions were placed in adjacent squares rather than in the same square and the samples were tested for 5 and 10 minutes only.

The results are shown in Figure 6 wherein Col is composition of the invention. They show the following:

30 After both 5 and 10 minutes - With Limelite, no limescale has been removed and the marker pen is the only way to see that it had been treated at all. Limelite dried very quickly. In contrast with the composition of the invention, limescale was effectively removed.

18

Compared to Viakal, the composition of the invention is significantly better at removing lime scale over a similar flat area. Viakal showed significantly less lime scale removal when compared to the composition of the invention, the area of removal being focussed solely on the area near the centre. The composition of the invention on the 5 other hand showed good lime scale removal across the whole area of the spot.

Compared to Limelite, the composition of the invention is significantly better at removing lime scale after 5 & 10 minutes. The composition of the invention also provided a visible shine to the surface of the tile.

10

Tap test

1. A bird's eye view picture was taken of 3 'spokes' of a tap handle made of chrome along with side-on views. Each spoke was assigned a 'time zone': control, 5 min., 10 min. & 15 min.

15 2. ~2.5g of composition was applied to each spoke and a timer started

3. After the respective time period (e.g. 5 minutes) the composition was removed by very light dabbing with a dry piece of kitchen roll and then by dabbing with a damp piece

4. A second picture is then taken

20

The results are shown in Figure 7 as follows:

Fig 7a (after 5 minutes): the composition of the invention removes significantly more lime scale compared to both Viakal and Limelite.

Fig 7b (after 10 minutes): although the composition of the invention has a few spots of 25 hard lime scale remaining after 10 minutes, the taps treated with Viakal and Limelite both have much more remaining. The composition of the invention also provides a better shine than Limelite and a comparable shine to Viakal.

Fig 7c (after 15 minutes): the composition of the invention shows significantly better removal of lime scale and improved shine than either Viakal or Limelite. Although the 30 tap treated with the composition of the invention still has a few small areas of tough lime scale remaining, it is believed that these could be removed by rubbing with a cloth.

Overall the composition of the invention is significantly better at removing lime scale from taps than both of Limelite and Viakal over 5, 10 & 15 minutes. Viakal could not 35 remove the majority of the lime scale after 5 minutes and at 10 and 15 minutes large

19

patches of lime scale are still visible. Limelite performed the most poorly of all of the compositions and significant areas of lime scale were still visible at the end of the test.

Other preferred compositions of the invention are described in the table below.

20

Ingredients

% wt

%wt composition

Time

Viscosity (cps)

PH

water

83.90%

84.455

initial (RT)

5550 (sp5; 20rpm)

1.41

Rhodopol extra 2 (RX2)

1.25%

1.25

Sulfamic acid

9.75%

9.75

formic acid 90%

4.75%

4.275

Link 706

0.25%

0.25

Flexipel SR-80 (FSR80)

0.10%

~0.02

water

83.87%

84.428

initial (RT)

5250 (sp5; 20rpm)

1.23

Rhodopol extra 2 (RX2)

1.25%

1.25

Sulfamic acid

9.75%

9.75

formic acid 90%

4.78%

4.302

Link 706

0.25%

0.25

Flexipel SR-80 (FSR80)

0.10%

~0.02

water

81.37

81.928

initial (RT)

5775(sp5; 20rpm)

1.04

Rhodopol extra2 clear,

1.25%

1.25

Propylene Glycol

2.50%

2.50

Sulfamic acid

9.75%

9.75

formic acid 90%

4.78%

4.302

Link 706

0.25%

0.25

Flexipel SR-80 (FSR80)

0.10%

-0.02

water

81.37%

81.928

initial (RT)

5800 (sp5; 20rpm)

1.51

Rhodopol extra 2 clear

1.25%

1.25

Propylene Glycol

2.50%

2.50

Citric acid (anhydrous)

9.75%

9.75

90% Formic acid

4.78%

4.302

Link 706

0.25%

0.25

Flexipel SR-80

0.10%

-0.02

21

Claims

CLAIMS:

1. A composition for treatment of lime scale comprising:

(i) water;

5 (ii) formic acid;

(iii) sulfamic acid and/or citric acid;

(iv) a thickener;

(v) a surfactant; and

(vi) a surface-modifying polymer,

10 wherein said composition has a viscosity of at least 4000 cps.

2. A composition as claimed in claim 1 having a viscosity of 4500-9000 cps.

3. A composition as claimed in claim 1 or 2 in the form of a gel.

15

4. A composition as claimed in any one of claims 1 to 3 having a pH of 0.75 to 3.0.

5. A composition as claimed in any preceding claim, further comprising a Ci-8 alcohol.

20

6. A composition as claimed in any preceding claim, wherein said composition comprises sulfamic acid.

7. A composition as claimed in any one of claims 1 to 6, wherein said composition 25 comprises citric acid.

8. A composition as claimed in any one of claims 1 to 6, wherein said composition comprises 5 to 15 %wt sulfamic acid and 3 to 7.5 %wt formic acid.

30

9. A composition as claimed in any one of claims 1 to 5 and 7, wherein said composition comprises 2.5 to 7.5 %wt citric acid and 10 to 20 %wt formic acid.

35

10. A composition as claimed in any preceding claim, wherein said thickener is a polysaccharide.

22

11. A composition as claimed in claim 10, wherein said thickener is xanthan gum or a derivative thereof.

12. A composition as claimed in any preceding claim, wherein said surfactant is a 5 non-ionic surfactant and a cationic surfactant.

13. A composition as claimed in claim 12, wherein said non-ionic surfactant is an alkoxylated alcohol.

10

14. A composition as claimed in claim 12 or 13, wherein said cationic surfactant is a di or trialkyl amine ethoxylate salt.

15. A composition as claimed in any preceding claim, wherein said surface-modifying polymer is formed from a trimethyl-[2-(2-methyl-1-oxoprop-2-

15 enoxy)ethyl]ammonium salt.

16. A compositon as claimed in any preceding claim, wherein said surface-modifying polymer is formed from trimethyl-[2-(2-methyl-1-oxoprop-2-enoxy)ethyl]ammonium chloride, 2-propenoic acid and 2-propenamide

20

17. A composition as claimed in any one of claims 5 to 16, wherein said Ci.8 alcohol is a diol.

18. A composition as claimed in claim 17, wherein said Ci_8 alcohol is propylene 25 glycol.

19. A composition as claimed in claim 1 comprising:

(i) 70 to 85 % wt water;

(ii) 3 to 7.5 %wt formic acid;

30 (iii) 5 to 15 %wt sulfamic acid;

(iv) 0.75 to 2.2 %wt thickener, preferably xanthan gum or a derivative thereof;

(v) 0.10 to 1.00 %wt surfactant, preferably a blend of non-ionic and cationic surfactant;

35 (vii) 1.0 to 4.0 %wt Ci_8 alcohol, preferably propylene glycol.

23

20. A composition as claimed in claim 1 comprising:

(i) 70 to 85 % wt water;

(ii) 10 to 20 % wt formic acid;

(iii) 2.5 to 7.5% wt citric acid;

5 (iv) 0.75 to 2.2 %wt thickener, preferably xanthan gum or a derivative thereof;

(vii) 1.0 to 4.0 %wt C-i-8 alcohol, preferably propylene glycol.

10

21. A composition as claimed in claim 1 comprising:

(i) 75 to 80 % wt water;

(ii) 12 to 15 % wt formic acid;

(iii) 3 to 7 % wt citric acid;

15 (iv) 1.0 to 2.0 %wt thickener, preferably xanthan gum or a derivative thereof;

(vi) 0.01 to 0.03 %wt surface-modifying polymer, preferably surface-modifying polymer which comprises side chains comprising an ammonium salt; and

(vii) 2.0 to 3.5 %wt Ci-8 alcohol, preferably propylene glycol.

20

22. A method of making a composition as claimed in any one of claims 1 to 21 comprising mixing (i) water; (ii) formic acid; (iii) sulfamic acid and/or citric acid; (iv) a thickener; (v) a surfactant; (vi) a surface-modifying polymer and optionally (vii) Ci.8 alcohol.

25

23. Use of a composition as claimed in any one of claims 1 to 21 for the treatment of lime scale.

24. A method of treating lime scale on a surface or object comprising:

30 (a) applying a composition as claimed in any one of claims 1 to 21 to said surface or object;

(c) optionally mechanically agitating said surface; and

(d) rinsing said surface or said object.

35

24

25. A method as claimed in claim 24, wherein said application is with a brush.

26. A method as claimed in claim 24 or 25, wherein said surface or object is non-planar.

5

27. A kit for the treatment of limescale comprising:

a composition as claimed in any one of claims 1 to 21; and a brush.

10

28. A kit as claimed in claim 27, further comprising instructions for use of the composition and brush.