Field of the Invention The present invention relates to a stain repellence composition for treating a substrate. More particularly the present invention relates to a composition for hydrophilic stain repellence and process for making a substrate repellent to hydrophilic stains.

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. Present days consumers are not only looking for fabric washing composition to remove the dirt. But, they are also looking for fabric treatment composition before-wash or after-wash to keep the fabric better and long-lasting. Different types of fabric care/treatment compositions are known in the art. Fabric care compositions serve a variety of purposes. The use of a fabric care composition is one of the ways to deliver and deposit different types of benefit agents onto the fabrics.

Fabric cleaning or care compositions that provide a so called next time cleaning benefit, are highly appreciated by present day consumers. By next time cleaning benefit is meant any treatment of a substrate prior to the deposition of dirt that enables easier cleaning upon the subsequent cleaning.

Similarly there is a need for compositions for the treatment of hard and soft surfaces (e.g. kitchen tops, tiles, carpets, upholstery, windows, including car windscreens, etc) that render the surfaces hydrophobic and/or repellent to aqueous stains.

Fabrics need to be cleaned from time to time depending on the perception of the cleanliness of the consumers. However, washing a fabric causes fabric damage. The more often a garment is washed, the more is the damage to the fabric. The damage of the fabric leads to the weariness and which subsequently leads to the older appearance of the fabric. One of the ways of keeping fabrics clean is not to expose it to the environment which will eventually make the fabric dirty. Less dirty the fabric is the frequency of washing will also be less. Due to reduced frequency of fabric washing the weariness will also be less and the fabrics will become long lasting.

Coating compositions using different fabric compatible polymers to reduce the dirt on the fabric have been disclosed in the art.

WO 91/04305 discloses an aqueous water repellent composition comprising the reaction product of one or more of a carboxylic acid or anhydride containing from 3 to 22 carbon atoms and a polyfunctional aromatic or aliphatic amine or substituted amine containing from 2 to 25 carbon atoms and a water soluble metal complex crosslinking agent containing one or more metals selected from Groups la, I la, Ilia, IVa and the first and second rows of transition metals from the Periodic Table of Elements. The composition may contain wax and is dispersed in water to form a water repellent system.

GB 849275 discloses an anti-fungal composition for treating fabrics comprises an aqueous solution containing a thermosetting aminoplastic resin and a water-soluble complex of 8-hydroxyquinoline with copper and chromium.

GB 844985 discloses a method for treating a substrate or surface to render it water repellent and hydrophobic, using a/o complexes with Manganese. Simlarly US 5733341 discloses Manganese chloride complexes.

However, a composition which will make fabrics and/or surfaces hydrophobic and therefore will repel stains which are hydrophilic in nature, remains to be desired.

Objects of the invention

In view of the foregoing, it is an object of the present invention to provide a composition that renders a substrate hydrophobic; and thereby make a substrate hydrophilic stain repellent. It is another object of the invention to provide fabrics/textiles resistant to getting dirty.

Surprisingly it has now been found that, hexamethylene tetramine (HMTA) complexed with bivalent transition metal ion in presence of trivalent and/or tetravalent metal ion in an aqueous medium can act as a hydrophilic stain repellence composition on the substrate and can make the substrate hydrophobic.

Summary of the invention Accordingly, the present invention provides a composition for treating a substrate comprising:

a) a preformed bivalent transition metal ion complex or its separate precursors comprising :

i. a bivalent transition metal ion or a Magnesium ion; and

ii. hexamethylenetetramine

b) a tri- or tetravalent metal salt,

wherein the molar ratio of bivalent transition metal ion to hexamethylene tetramine is in the range of 2:1 to 1 :10 and the molar ratio of trivalent or tetravalent metal ion to bivalent transition metal ion is in the range of 10:1 to 1 :10.

In another aspect, the present invention provides a process for making a substrate hydrophilic stain repellence comprising the steps of (a) spraying the composition of the invention on a substrate, (b) drying the substrate.

In another aspect the invention provides the use of the composition according to the invention to make a substrate hydrophobic.

By the term hydrophilic stain repellence in the present invention is meant that, the composition according to the invention will make a substrate hydrophobic. Due to the enhanced hydrophobicity of the substrate, it will not attract any hydrophilic material therefore becomes repellent to hydrophilic stains.

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. 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

According to the present invention the composition comprises a preformed bivalent transition metal ion complex or its separate precursors comprising of a bivalent transition metal ion and HMTA. By mentioning transition metal here we mean the d- block element of the periodic table which includes groups 3 to 12 on the periodic table. The preferable bivalent transition metal includes Zinc, Copper, Manganese, Iron (II), Cobalt or Nickel or the mixtures thereof. The present inventors have also found that apart from transition metal Magnesium can also be used for the purpose of the invention. According to one aspect of the invention a preformed complex of bivalent transition metal ion with Hexamethylene tetramine is being added to the composition. Bivalent transition metal ion is known to form complex with Hexamethylene tetramine.

Hexamethylene tetramine (HMTA) or Hexamine or Urotropin is a known organic ligand for complexation reaction. It is an organic heterocyclic compound having the formula (CH ₂ )6N ₄ having the following structure:

It is soluble in water and most of the polar organic solvents. It is a well known compound in complex chemistry for its ability to form complex with divalent transition metals like Zinc, Copper, Nickel etc. Hexamine undergoes hydrolysis at a temperature of 90-100 degree centigrade.

The preferable salts of bivalent metal ion for the purpose of complexation is selected from Zinc Nitrate, Zinc chloride, Copper nitrate, Manganese nitrate, Ferrous nitrate, Cobalt nitrate, Copper (ii) chloride, Manganese Chloride, Ferrous chloride.

In case where Magnesium is used the corresponding salt is selected from Magnesium chloride, Magnesium nitrate etc.

The composition of the invention also contains a trivalent or tetravalent metal salt, or mixtures thereof.

The preferable trivalent cation of said salt includes Aluminum, Titanium (III), Chromium or iron (III) or mixtures thereof. These trivalent ions are preferably added to the composition in the form of their salts. If the trivalent metal ion is Aluminum the counter ion is preferably selected from chloride, nitrate, acetate or formate or mixtures thereof. The most preferable trivalent salts are selected from Aluminum chloride, Titanium (III) chloride, Ferric chloride, Chromium chloride, Aluminum nitrate, Chromium nitrate, Ferric nitrate.

The preferred tetravalent metal ion is selected from Titanium (IV) or Zirconium. The preferred salt of the tetravalent metal ion is selected from Titanium (IV) chloride or Zirconium chloride. Thus the present invention provides hydrophilic stain repellence composition comprising a preformed bivalent transition metal ion complex or its separate precursors comprising; (i) a bivalent transition metal ion or Magnesium ion; and (ii) hexamethylene tetramine and a tri or tetravalent metal salt.

5

The preferable molar ratio of bivalent transition metal ion to hexamethylene tetramine is in the range of 2:1 to 1 :10 and the preferable molar ratio of trivalent or tetravalent metal ion to bivalent transition metal ion is in the range of 10:1 to 1 :10. The most preferable range of the molar ratio of trivalent or tetravalent metal ion to bivalent transition metal 10 ion to hexamethylene tetramine is about 1 :2:4.

According to the present invention the bivalent metal ion complex of HMTA may be directly added to the composition or bivalent metal salt and HMTA may be separately added to the composition.

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Preferably a ready to use liquid hard surface treatment composition comprises 1 - 80 g/L of the 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. Such compositions are typically packaged in the form of a trigger 20 spray dispenser.

For fabric care, the compositions may be in the form of solid or liquid compositions.

Solid compositions typically comprise at least 50% by weight, more preferably at least

25 70%, still more preferably at least 80%, even more preferably at least 90%, or even up to 100% by weight of the composition for treating a substrate according to the invention.

A liquid fabric care composition typically comprises 20-90% by weight of the

30 composition for treating a substrate according to the invention, more preferably at least

50%, still more preferably at least 60%, but preferably less than 85%, more preferably less than 80% in a solvent. The solvent is preferably water, or a lower alcohol, such as methanol, ethanol, propanol, preferably 2-propanol. The liquid composition may be further stabilized and/or thickened in any conventional way.

Optional ingredients

The compositions of the invention may also contain one or more optional ingredients, selected from pH buffering agents, perfume carriers, fluorescers, colorants, hydrotropes, antifoaming agents, antiredeposition agents, enzymes, optical brightening agents, opacifiers, anti-shrinking agents, anti-wrinkle agents, anti-spotting agents, germicides, fungicides, anti-corrosion agents, drape imparting agents, antistatic agents and ironing aids. It will be appreciated that the use of other ingredients in the composition is apparent for those skilled in the art.

Forming the complex

To form complex with hexamethylene tetramine the measured amount of selected bivalent metal ion salt may be dissolved in ethyl alcohol and measured amount of HMTA is also dissolved in ethyl alcohol to make almost saturated solutions. The two different solutions are then added in a pool of ethyl alcohol. The reaction mixture is stirred using a magnetic stirrer while adding the reagents. After the addition it is generally kept sometimes for ageing. The precipitated complex then filtered and washed several times with ethyl alcohol. It is subsequently then dried.

The complex may also be formed in an aqueous medium, such as washing liquor.

Treating a substrate

In another aspect the invention provides a process for making a substrate hydrophilic stain repellent comprising the steps of: (a) spraying the composition according to the invention on a substrate, and (b) drying the substrate. The spaying step is just to ensure that the substrate is substantially coated by the composition of the invention. It will be appreciated that any other means apart from spraying, that give rise to substantial coating of the fabric with the composition are also included here. The spraying step is followed by the drying step. According to one of the preferred aspect of the present invention the drying step is carried out at an ambient temperature. Ambient temperature here means temperature around 20°C - 30°C. But, it also can be carried out at an elevated temperature or in an atmosphere having higher than ambient temperature.

For the avoidance of doubt, the submersion of fabric in water comprising the substrate treatment composition is included in the scope of this invention.

Optionally after drying the substrate can be additionally treated with a fatty acid solution to increase the degree of hydrophobicity. The fatty acid solution may be sprayed in the same way as the composition of the invention. The fatty acid for this purpose is preferably selected from saturated fatty acid soap having carbon chain length ranging from Ci2 to C ₂ 4 preferably from C12 to Ci ₈ . The most preferred fatty acid is selected from Laurie acid, Myristic acid and Stearic acid. The fatty acid solution preferably prepared by dissolving the fatty acid in a solvent preferably alcohol. The amount of fatty acid in the solvent is preferably in the range of 1 to 20 g/L more preferably 2-6 g/L.

After the above treatment, if the substrate is a fabric, then it can be optionally moist ironed. By mentioning moist ironing here we mean ironing with water sprinkle. Ironing the treated and treated fabric with sprinkle of water to produce particles on the fabric and it makes the surface of the fabric rough enough to add more hydrophobicity. It has been found that the degree of hydrophobicity is even higher in the moist-ironed fabric than the dried fabric. But in the absence of moist-ironing stage the dried fabrics are also adequately hydrophobic to repel hydrophilic stain. Moist ironing stage is preferable when the precursors of the HMTA complex added separately compared to when preformed complex is added.

The temperature of the moist ironing stage is preferably in between 60-1 10°C, more preferably from 70-105°C and most preferably from 85-100°C. The temperature mentioned here is the temperature of the iron. The intended use of the composition of the invention is to make a substrate hydrophobic to repel hydrophilic stain. The substrate can be fabrics, textiles, kitchen tops, tiles, carpets, upholstery, windows, including car windscreens etc. Now the invention will be demonstrated by way of non-limiting examples. The examples are for illustration only and do not limit the scope of the invention in any manner.

Examples:

Example 1 : Comparison of hydrophobicity for treated and untreated fabrics

The test used for the purpose of the invention, determines a treated fabric's resistance to wetting by aqueous liquids. Drops of water-alcohol mixtures of varying surface tensions are placed on the fabric, and the extent of surface wetting is determined visually. This test provides an index of aqueous stain repellence. The test solutions used for the experiment are as follows:

2.7g of fabric (10 X 10 cm ² ) was separately dipped in the above mentioned sets of solutions for 2 hours each. Then the fabrics were removed from the solutions and dried in air. The dried fabrics were cut into two pieces. One portion of the fabric was ironed after sprinkling water on it at a temperature of ~ 105°C till the fabrics were dry.

In this process the test fabric was placed face up on a glass microscopic slide. Beginning with Test Liquid No. 0, 10 microlitre droplet of the solution was placed on the test fabric. The drop was observed for 10 seconds from an approximate 45° angle. If the droplet did not wet the fabrics then the next mixture solution was added in the same manner. The fabric's water repellency rating was the highest numbered liquid for which at the droplet did not wet or wick into the fabric. The results are shown in the following table:

In the above experiment the amount of (A), (B), (C) are 500 mg, 450 mg and 190 mg respectively. The treatment solutions were made by dissolving the described amount of (A), (B), (C) in 100 ml of water.

Example 2: Comparison of hvdrophobicity of the treated and untreated fabric wherein the precursors were added separately but not as a complex

The same procedure as discussed in the Example 1 was used for this purpose:

Fabric Treatment drop test no. (With

drying + Moist Ironing)

Zinc Nitrate hexa hydrate + HMTA 0

Zinc Nitrate hexahydrate + HMTA + 1

Aluminium nitrate

Manganese Nitrate tetrahydrate + HMTA 0

Manganese Nitrate hexa-hydrate + HMTA+ 2

Aluminium nitrate

Copper Nitrate trihydrate + HMTA 0 Copper Nitrate trihydrate + HMTA + 2

Aluminium nitrate

Magnesium Nitrate hexahydrate + HMTA 0

Magnesium Nitrate hexahydrate + HMTA+ 1

Aluminium nitrate

In the above example the amount of Zinc Nitrate hexahydrate, Manganese Nitrate tetrahydrate, Copper Nitrate trihydrate, Magnesium Nitrate hexahydrate, HMTA and Aluminium nitrate are respectively 294 mg, 248 mg, 254 mg, 239 mg, 278 mg and 190 mg. The treatment solutions were made by dissolving the described amount of the ingredients in 100 ml of water.

Example 3: Comparison of hydrophobicity of the treated and untreated surface other than fabric.

500 mg of Zn-HMTA complex of probable formulae and 190 mg Aluminum nitrate monohydrate was dissolved in 100 ml of distilled water. 5 ml of the solution was added to a clean glass slide/ stainless steel plate, spread over the surface, left for 5 minutes and then wiped off with a tissue paper till completely dry. The contact angle of a 20 microlitre of water droplet was measured on the treated and the untreated surfaces.

Contact angle (in degree):

Type of Surface Treated with the composition Untreated

Glass 72 21

Stainless steel 79 65 From the table it is apparent that after the treatment the contact angle is increased. The higher the contact angle the more hydrophobic the surface is. So there is an increase in the hydrophobicity of the treated surface.