TECHNICAL FIELD

This invention relates to a method and composition for treatment of a hard surface. It particularly relates to a method and composition for treatment of a surface for imparting repellence of aqueous soils.

BACKGROUND AND PRIOR ART

Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of the common general knowledge in the field.

Hard surfaces in the home or office are usually cleaned using liquid compositions which comprise one or more surfactants and possibly also pH adjusters like citric acid or sodium salts of citrate. The cleaning compositions can be applied in diluted (in water) or undiluted form, in a spray, or rubbed using a cloth and any other convenient way. Optionally the cleaning composition may be rinsed from the surface after the cleaning. It would be advantageous if the hard surface to be cleaned could be treated with a material which would assist in easier removal of soil and/or stains during subsequent cleaning. This is referred to as the next time cleaning benefit.

Soils on hard surfaces can become more difficult to remove when not cleaned soon after deposition. When not cleaned promptly, soils can become more adherent to surfaces, more viscous and generally tougher, and require more effort to clean. While not being bound by theory, this more difficult removal of soils can arise from the effects of drying out of soils, from chemical changes in soils, from reactions of soils with environmental agents such as oxygen, etc. Some soils are more susceptible than others to toughening reactions and processes. Soils comprising or containing chemically unsaturated oils and fats can become very tough and difficult to clean over time, especially when exposed to elevated temperatures. Even light can cause such fatty soils to toughen over time. As well as environmental factors, the processes of toughening of soils can be affected by the nature and composition of the surface on which the soil is located.

WO 02/18531 discloses a method for cleaning hard surfaces, wherein the surface is treated with an antioxidant, followed by allowing the surface to become dirty, and subsequently cleaning the surface. The treatment of the surface with the antioxidant prior to the soiling, leads to easier removal of the soil during the subsequent cleaning step. The antioxidant may be present in a cleaning composition, or in a rinse composition that is applied after the cleaning. In addition cleaning compositions comprising antioxidants, preferably at a concentration of 0.1 -10 % by weight, are disclosed. Tannic acid was exemplified to be notably efficient.

Similar methods are disclosed in WO 03/07289 A1 and WO 2006/108475 A1 discloses a method for removing fatty soil from a hard surface, the process comprising the sequential steps of (a) treating the hard surface with a liquid cleaning composition; (b) allowing the fatty soil to deposit; and (c) cleaning the surface to remove the fatty soil.

Self cleaning surfaces are disclosed in WO04037944 A1 , wherein a process and a composition are disclosed for producing surfaces that are self-cleaning by water, and in particular, there is disclosed an aqueous system for forming transparent self- cleaning surfaces. In the process of WO04037944 A1 , an aqueous mixture

comprising Nan particles having a particle size of less than 300 nanometers and a surface modifier selected from the group consisting of water-soluble hydrophobic surface modifiers and water-dispersible hydrophobic surface modifiers capable of forming a continuous film from an aqueous solution is provided. The aqueous mixture is applied to a surface, and a self-cleaning transparent coating is formed on the surface upon water evaporation. In one embodiment, the aqueous mixture is essentially free of organic solvents other than coalescing solvents.

In spite of the advantages, the antioxidants as disclosed by the prior art also may suffer from disadvantages. Consumers may regard residues of antioxidants and/or Nan particles acid on the hard surfaces in e.g. kitchen and bathroom to be harmful and undesired. It is an object to provide a hard surface cleaning composition providing soil repellence to a surface.

It is a further object of the invention that the composition can be applied reversibly. It is a further object of the invention that the surface treated with the composition is rendered water repellent.

It is yet another object of the invention to provide such a composition that composition further provides oily soil removal.

Surprisingly it has been found that applying a composition comprising a trivalent metal ion, a saturated fatty acid salt and a silicone oil to a hard surface, renders said surface water repellent. Summary of the invention

Accordingly, the present invention provides a hard surface treatment composition having a pH of not more than 8, comprising a base composition comprising: 20-75% by weight of a water soluble trivalent metal ion salt; 20-75% by weight of a saturated C ₈ -C ₂ 4 fatty acid soap, and 5-20% by weight of a silicone oil.

In another aspect the invention provides a method for treating a hard surface comprising the steps of: applying the composition according to anyone of claims 5 or 6 to a hard surface and leaving the surface to dry. In yet another aspect the invention provides the use of a composition according to anyone of the preceding claims for rendering a surface water repellent.

These and other aspects, features and advantages will become apparent to those of ordinary skill in the art from a reading of the following detailed description and the appended claims. 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." In other words, the listed steps or options need not be exhaustive. 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.

Similarly, all percentages are weight/weight percentages unless otherwise indicated. Except in the operating and comparative 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". Numerical ranges expressed in the format "from x to y" are understood to include x and y. When for a specific feature multiple preferred ranges are described in the format "from x to y", it is understood that all ranges combining the different endpoints are also contemplated.

Detailed description of the invention

A hard surface treatment composition comprising a base composition comprising a water soluble trivalent metal ion salt, a saturated C ₈ -C ₂ 4 fatty acid soap, and a silicone oil.

Base composition

The base composition comprises a water soluble trivalent metal ion salt, a saturated C ₈ -C ₂ 4 fatty acid soap, and a silicone oil, and provides the water and/or soil repellence benefit.

In solid hard surface treatment compositions, the base composition is preferably present in a concentration of between 10 and 100% by weight of a solid the hard surface treatment composition, more preferably more than 20%, still more preferably more than 30%, even more preferably more than 40%, or even more than 50% by weight, while the solid hard surface treatment composition preferably comprises less than 90% by weight of the base composition.

In concentrated liquid hard surface treatment compositions the base composition is preferably present in a concentration of between 10 and 1000 g/L, more preferably between 1 and 600 g/L, still more preferably between 10 and 500 g/L or even between 100 and 300 g/L. In ready to use liquid hard surface treatment compositions the base composition is preferably present in a concentration of between 0.5 and 100 g/L, preferably more than 1 g/L, still more preferably more than 2 g/L, or even more than 5 g/L, while the composition preferably comprises less than 75 g/L, more preferably less than 60 g/L, still more preferably less than 50 g/L, even more preferably less than 40 g/L or even less than 30 g/L

Trivalent metal ion salt

The water soluble trivalent metal ion salt has solubility of at least 0.05 g per 100 g water at 25 °C. The solubility of the trivalent metal ion salt is preferably greater than 0.1 , more preferably greater than 1 and most preferably greater than 5 g per 100 g of water at a temperature of 25 °C.

The trivalent metal ion is preferably selected from aluminium, iron, chromium, bismuth or titanium, more preferably the trivalent metal is chosen from aluminium or iron, most preferably, the trivalent metal is aluminium. Chromium III is not preferred for household use as it is toxic.

The anion of the water soluble trivalent metal ion salt is preferably selected from chloride, phosphate, nitrate, and sulphate.

An especially preferred trivalent metal ion salt is poly aluminium chloride.

The trivalent metal ion salt is present in the base composition in a concentration of between 20 and 75% by weight, preferably more than 25%, more preferably more than 30%, still more preferably more than 35%, but preferably not more than 70%, more preferably not more than 65%, still more preferably not more than 60%, or even less than 55% by weight of the base composition. Fatty acid soap

The saturated soap is a water soluble C ₈ -C ₂ 4 soap, preferably C ₈ -C ₂ o soap, more preferably C ₈ -Ci ₆ soap, and most preferably C ₈ -Ci ₄ soap. By saturated soap is meant in the context of the present invention that the iodine value of the soap, which is commonly known and used in the art to indicate the degree of unsaturation, is preferably less than 20, more preferably less than 10, and most preferably less than 5. Saturated soap having no carbon-carbon double bond or triple bond is particularly preferred.

The soap may be water-soluble or water insoluble. Non-limiting examples of water- soluble soaps that can be used according to the present invention include sodium or potassium laureate, sodium or potassium caprylate, and potassium myristate and mixtures thereof.

The fatty acid soap is present in the base composition in a concentration of between 20 and 75% by weight, preferably more than 25%, more preferably more than 30%, still more preferably more than 35%, but preferably not more than 70%, more preferably not more than 65%, still more preferably not more than 60%, or even less than 55% by weight of the base composition.

Silicone oil

The base composition further comprises a silicone oil, preferably a quaternary silicone oil, e.g. PDMS (poly dimethyl siloxane), PMHS (polymethylhydroxysiloxane), isobutyltrimethoxysilane, octadecyl trichloro silane, triisopropylsilane or their combinations.

This silicone oil is present in the base composition in a concentration of between 5 and 20% by weight. The base composition preferably comprises less than 15% by weight.

Hard surface treatment composition

Apart from the base composition, the hard surface treatment composition may further comprise pH modifying agents, anti-microbial agents, further surfactants, electrolytes, and sensorial molecules including fragrances, fluorescer molecules, dyes and shading dyes Solvent

Liquid hard surface treatment compositions comprise the base composition according to the invention and a solvent.

The solvent is preferably selected from water and lower alcohols. Preferred alcohols include methanol, ethanol, 1 -propanol and 2-propanol (also known as iso-propanol, or isopropyl alcohol), 2-propanol being the most preferred.

The solvent is preferably a mixture of water and alcohol. The alcohol provides faster evaporation from the surface and aids in the solubilisation of oily soils. Although the alcohohwater ratio of such mixtures may be anything between 1 :99.9 and 99.9:1 , preferably the ratio is between 2:98 98:2, more preferably the ratio is between 5:95 and 30:70, most preferably between 10:90 and 25:75.

Antimicrobial agent

The hard surface treatment compositions may further comprise an anti microbial agent, which is preferably selected from alcohols, including linalool, geraniol, menthol, terpineol; phenols, including thymol, carvacrol and eugenol; salicylic acid derivatives, and zinc based anti-bacterial agents, including zinc chloride, silver salts and copper salts. pH modifying agent

The hard surface treatment compositions according to the invention may further comprise a pH modifying agent. Typical pH modifying agents in the context of the present invention include both acidic and alkaline pH modifying agents. Acidic pH modifying agents include both inorganic as well as organic acids. Alkaline pH modifying agents include both inorganic as well as organic bases. Preferred alkaline pH modifying agents are selected from

carbonates, bicarbonates, polyphosphates and hydroxides of alkali metal.

The pH of the aqueous components is preferably below the iso-electric point. The pH of the hard surface cleaning composition at the concentration of use is preferably between 1 and 8, more preferably below 6 or even below 4. Thus, the hard surface treatment composition has a pH of not more than 8 at a concentration of 0.5 to 100 g/L of the base composition in water.

Surface

The hard surface may be any household or industrial hard surface. Typical hard surfaces include windows, tiles and other ceramic materials, metal surfaces, cooker tops, etc.

Treatment

The treatment of hard surfaces with the compositions as described above, are included in the scope of the present invention.

The use of a composition according to anyone of the preceding claims for rendering a surface water repellent is also included.

It is preferred that the compositions are applied to the hard surface in the form of a concentrated or dilute liquid composition.

Preferably a liquid hard surface treatment composition comprises 1 - 50 g/L of the base composition according to the invention dissolved in the solvent; more preferably at least 2 g/L or even at least 5 g/L, while preferably less than 40 g/L or even less than 25 g/L.

The treatment is typically by treating a surface with the composition according to the invention. The surface is preferably cleaned prior to treatment. The surface is left to dry. After drying the surface will then exhibit water repellence and repellence aqueous stains.

Examples

The invention will now be illustrated by means of the following non-limiting examples. Example 1 : water repellence test In this example the water repellence effect of the compositions according to the invention are compared with comparative examples outside the claimed range.

In this example poly aluminium chloride (PAC, ex Grasim, India), Na soap of distilled coconut fatty acid (DCFA, ex Godrej Industries Ltd, India) and

polymethylhydroxysiloxane (PMHS, ex Aldrich, USA) were dissolved in distilled water in the concentrations given in the table below. In the comparative examples, no PDMS was used.

The material was applied to a glass surface by applying 2 mL of the formulation over one side of a 100 cm2 of a glass surface. The layer of liquid was left on the glass surface for ~ 30 seconds. The glass surface was wiped with a tissue paper till it is completely dry. The glass surface hydrophobicity was determined by water droplet contact angle testing.

The contact angle of a sessile droplet was measured using a Kruss goniometer by placing a 10 microlitre of distilled water droplet on the glass slide. The angle was analyzed by the image J software using the Drop snake plug-in.

The roll off angle was measured by applying 50 microlitre of water onto a glass slide (microscope glass slide) and by tilting the treated glass slide over a fixed point. + refers to the easily sliding behaviour therefore more stain repellent; and - refers to sticking behaviour therefore less stain repellent The transparency was determined by means of the transmittance of the substrate (glass slide) that was measured in comparison to the untreated surface using a Perkin Elmer Lambda 35 uv-vis spectrophotometer between 400-700 nm.

Initial turbidity of the solutions (before applying to the surface) was measured using a Merck Turbiquant 1500T. For reference the turbidity of distilled water was found to be 0.64 NTU.

The results are given in the table below.

The table above shows that all examples and comparative examples provide a treated surface without compromising the transparency. The contact angle, as a measure for the water repellence, in the examples and comparative examples are high. However, only the examples show good sliding behaviour, thus reducing deposition of soil to the surface.

Example 2: water repellence example

In this example the effect of PAC, DCFA and PDMS individually or using 2 out of 3 are compared to the composition according to the invention including all 3 ingredients. In this example the material is applied in the same way as in example 1 and the contact angle is tested according to the same method.

The table above shows that the highest contact angle (i.e. the best result) is obtained by the composition according to the invention.

Example 3: Liquid composition comprising an alcohohwater mixture.

The effect of mixtures of 2-propanol and water is tested according to the same protocol as example 1 , but now dissolving 5 g/L of PAC, 5 g/L DCFA and 1 g/L of PMHS.

The rate of evaporation of the different formulations was studied by putting 10 microlitre of the solution and smearing it on a 2.5cmX7.5cm glass microscopic slide. The time for drying was evaluated using a stopwatch.

Results are found in the table below.

Set No. I PA: water Rate of Contact angle

(v/v) evaporation (degree)

(sec)

untreated 137 (only 22

water) Example 3 0:100 121 82

Example 4 2:98 1 18 84

Example 5 5:95 75 94

Example 6 10:90 65 86

Example 7 20:80 61 89

Example 8 30:70 58 92

Example 9 40:60 54 88

Example 10 60:40 51 86

Example 1 1 70:30 46 85

Example 12 80:20 41 81

Example 13 90:10 38 83

Example 14 98:2 33 83

The results in the table above show that there is not substantial difference in the contact angle, i.e. in the water repellence effect, for using an alcohol water mixture, but there is a further benefit in the rate of evaporation when using at least some alcohol as solvent.

Example 4: pH effect

The composition of Example 1 , example composition 3, was used at different pH, wherein the pH was adjusted with 1 M hydrochloric acid (HCI) or with 1 M caustic soda (NaOH).

The roll off angle for 50 microlitre of water was measured by tilting the treated glass microscopic slide about a fixed point; wherein + refers to the easily sliding behaviour therefore more stain repellent; - refers to sticking behaviour therefore less stain repellent.

Treatment Solution at diff. pH Observation

2 Streak (+)

4 Streak (+)

6 Streak (+) 8 Streak (+)

10 Stick (-)

12 Stick (-)

The results above show that the water repellence effect is not obtained at a pH above 8.