The present invention relates to a composition and a method for treating substrates, such as fabrics; particularly to make the substrate stain repellent.

The invention has been developed primarily for use on fabrics and glass, and will be described hereinafter with reference to these applications.

Background of the invention

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.

Fabrics and hard surfaces are generally cleaned with detergents. Standard detergent compositions include surfactants and builders. Surfactants clean the fabrics. Some detergent compositions also contain soda ash to enhance the cleaning action. Many detergent compositions also include specialty polymers that help release stains. Such polymers are called soil release polymers (SRP). Some detergent compositions also include additives that reduce re-deposition of dirt which is released in the wash liquor. Such additives are called Anti-redeposition agents (ARD). Fabrics and hard surfaces tend to get stained during use. Stains are generally, either oily, or aqueous. Common sources of aqueous stains include tea, coffee, beverages and inks. Common sources of oily stains include pickles, sauces and ketchups, motor oil, and grease. People do prefer to wear clothes with lesser stains. This is particularly applicable to white fabrics, such as white shirts. People also prefer that kitchen, bathroom surfaces and windows surfaces are free of stains.

One of the ways to prevent fabrics and hard surfaces from getting stained is to treat them with compositions that form a film on the surface of the fabric or hard surface. This film prevents, or at least reduces, the adhesion of stains. The film also allows for facile removal of stains during washing, and it may be said to form a sacrificial layer. Salts of metals are generally present in such compositions. Surfaces get stained when stains spreads on it. In such cases, the stain wets the surface. When a stain wets a surface, the contact angle between the stain and the surface is very low, generally less than 10°. When a surface treatment composition forms a film, the film increases the contact angle. In other words, this film doesn't allow the stain to wet the surface.

Generally, water contact angle in the range of 90° to 170° is considered to be good for repelling aqueous stains. On the other hand, oil contact angles greater than 60 are considered to be good for repelling oily stains. Such treated surfaces may be termed as super-hydrophobic or super-oleophobic.

The contact angle is the angle at which a liquid/vapour (or two immiscible liquids) interface meets a solid surface. The contact angle is specific for any given system and is determined by the interactions across the two interfaces. Most often, the concept is illustrated with a liquid droplet resting on a flat horizontal solid surface. The shape of the droplet is determined by Young-Laplace equation. One of the ways to measure contact angle is to use a contact angle goniometer on a sessile drop of the liquid. This method is used to estimate wetting properties of a localized region on a solid surface. The angle between the baseline of the drop and the tangent at the drop boundary is the contact angle.

Fabric treatment compositions have been described in co-pending unpublished Indian applications 1372/MUM/2010 and 1373/MUM/2010, (filed by Hindustan Unilever Limited).

1373/MUM/2010 describes stain repellent liquid compositions and a method for their use. The compositions help make substrates, particularly fabrics, repellent to hydrophilic stains. The compositions include 25 to 50 wt% soap, 10 to 30 wt% a complex of zinc and triethanolamine, 30 to 65 wt% trivalent metal ion and/or tetravalent metal ion, and a solvent having a lower alcohol and water in a ratio of 99: 1 to 85: 15.

It is known that polymers, especially silicones and silanes, and more particularly fluoro silanes, are also good at repelling stains. Some of these compositions are particularly effective against (i.e. they repel more of) aqueous stains, while some are effective only against oily stains. Compositions that provide both oil and water repellant compositions with improved adhering properties, are also disclosed in the art.

US6361871 (Jenkner et al., 2002) discloses surface modifying coating composition with better adhering properties, a process for preparing the coating composition and method for its use. The coating composition attaches to a polar substrate strongly and permanently providing improved coating. The coating composition includes atleast one organo fluorine-functional silane and/or siloxane, atleast one mineral acid and atleast one metal salt of aluminium (III), tin (II), tin (IV), iron (III) or titanium (III). This application however does not disclose a composition for application as a sacrificial layer that temporarily adheres to the fabric surface, making it stain repellant.

US6426150 (Jenkner et al., 2002) discloses a surface-modified insulator, method for modifying the surface of an insulator and a coating composition. The surface-modified insulator includes an insulator body having a coating on atleast a portion of atleast one organo fluorine-functional silane, organo fluorine-functional siloxane, or a mixture thereof, atleast one mineral acid and atleast one metal salt selected from a group consisting of aluminium (III), tin (II), tin (IV), iron (III) or titanium (III). This application teaches a coating composition that provides with a water oil and dirt repellant coating having improved adhesion properties and provides a homogeneous, highly cross linked coating on the insulator that remains fully and permanently bonded for long term.

Therefore the teaching of this application cannot be used for providing aqueous and oily stain repellant sacrificial layer on surfaces such as fabrics. However, a composition providing both aqueous and oily stain and soil repellence remains to be desired.

It is therefore an object of the invention to provide a composition for treating a substrate that enables easier cleaning on the subsequent wash or cleaning.

It is an object of the present invention to provide both aqueous and oily stain repellence. We have determined that some or all the problems of prior art may be solved or ameliorated with aqueous-alcoholic compositions which include a water-soluble salt of a multivalent metal ion, and a fluoro alkoxy silane. Such compositions have been found to provide higher repellence towards aqueous as well as oily stains. The combination shows surprising synergistic effects that are an order of magnitude better than those shown individually by the water-soluble salt of the multivalent metal ion and the fluoro alkoxy silane. We have determined that one would generally need a higher amount of the individual ingredients when used by themselves, but the combination allows for use of lower amounts of individual ingredients in the compositions.

Summary of the invention

According to a first aspect, the present invention provides a composition for treating a substrate, the composition including:

i. 0.05 wt% to 10 wt% water-soluble salt comprising a multivalent metal ion;

ii. 0.25 wt% to 5 wt% fluoro alkoxy silane;

iii. water; and,

iv. a Ci to C ₄ alcohol.

wherein ratio of said water-soluble salt to said fluoro alkoxy silane is from 1 :5 to 5: 1.

According to a second aspect, the present invention provides a process for making a composition of the first aspect, the process including a step of mixing 0.05 parts by weight to 10 parts by weight water-soluble salt which includes a multivalent metal ion and 0.25 parts by weight to 5 parts by weight fluoro alkoxy silane with water and a Ci to C ₄ alcohol to get 100 parts of the composition.

According to a third aspect, the present invention provides a method for treating a substrate which includes the steps of:

(i) applying a solution of the composition of the first aspect to form a

coating on a substrate; and,

(ii) drying the coating. According to a fourth aspect, the present invention provides use of a composition of the first aspect for treating a substrate to make it hydrophobic and oleophobic.

The invention will now be explained in detail.

The term "comprising" is meant not to be limiting to any subsequently stated elements but rather to encompass non-specified elements of major or minor functional importance. In other words the listed steps, elements or options need not be exhaustive. Whenever the words "including" or "having" are used, these terms are meant to be equivalent to "comprising" as defined above.

It should be noted that in specifying any range of concentration or amount, any particular upper concentration can be associated with any particular lower

concentration or amount.

The terms weight percent, percent by weight, % by weight and wt% are synonyms that refer to the concentration of a substance as the weight of that substance divided by the weight of the composition and multiplied by 100.

The recitation of numerical ranges by endpoints includes all numbers subsumed within that range (e.g. 1 to 5 includes 1 , 1.5, 2, 2.75, 3, 3.80, 4, and 5).

As used in this specification and the appended claims, the singular forms "a", "an", and "the" include plural referents unless the content clearly dictates otherwise. Thus, for example, reference to a composition containing "a compound" includes a mixture of two or more compounds. As used in this specification and the appended claims, the term "or" is generally employed in its sense including "and/or" unless the content clearly dictates otherwise. In the context of the present invention, by "glass surface" is meant any surface having a vitreous or vitrified surface, including but not limited to glass and vitreous tiles. Detailed description of the invention

In accordance with a first aspect, the invention relates to a composition for treating a substrate. The composition includes:

(i) 0.05 wt% to 10 wt% water-soluble salt which includes a multivalent metal ion; (ii) 0.25 wt% to 5 wt% fluoro alkoxy silane;

(iii) water; and,

(iv) Ci to C ₄ alcohol.

wherein ratio of said water-soluble salt to said fluoro alkoxy silane is from 1 :5 to 5: 1. The water-soluble salt:

The water-soluble salt includes a multivalent metal ion. The multivalent metal ion may be divalent, trivalent, or may have higher valency, such as tetravalent. Suitable metals may be selected from alkaline earth metals, transition metals, inner transition metals, Lanthanides and Actinides. Alkaline earth metals and transition metals are preferred over others, as they are safer to use. Simple salts such as nitrates or sulphates are preferred over compound salts, double salts and polymeric salts, but such compound, double and polymeric salts may also be used.

Preferred multivalent metal ions may be selected from Al ³⁺ , Ca ²⁺ , Zn ²⁺ , Cu ²⁺ , Ti ³⁺ or Fe ³⁺ . Preferred trivalent metal ions are Al ³⁺ and Fe ³⁺ ; Al ³⁺ is particularly preferred. Preferred divalent metal ions are Ca ²⁺ and Cu ²⁺ .

The water soluble salt may also be of any tetravalent metal ion. Preferably the tetravalent metal ion is Ti ⁴⁺ . However, salts of trivalent metal ions are preferred over salts of tetravalent metal ions.

Particularly preferred water-soluble salts include Aluminium nitrate, Calcium nitrate, Zinc nitrate, Copper nitrate, Ferric nitrate, Copper sulphate, Calcium chloride,

Aluminium sulphate, Aluminium chloride and Titanium chloride. The salt may be hydrated, or anhydrous.

The salt may be acidic or alkaline. Preferred acidic salts include nitrates, chlorides and sulphates. Alkaline compounds can be used provided that the pH is reduced by use of a pH modifier. Preferred alkaline salts include aluminates. Sodium aluminate is one such salt. In this case, it is preferred that the molar ratio of Na ₂ 0 to Al ₂ 0 ₃ is from 1.5: 1 to 1 :1 , more preferably from 1.3:1 to 1 : 1 and most preferably from 1.25:1 to 1.1 : 1.

Some particularly preferred Aluminium salts include Polyaluminium chloride and Polyaluminium sulphate. Water-insoluble Aluminium compounds like clays, alumina and aluminium hydroxide may not be suitable. While it is preferred to use only one salt, a mixture of salts may also be used.

The preferred compositions include 0.05 wt% to 10 wt% of a water-soluble salt, more preferably 0.1 wt% to 5 wt%, and most preferably 0.5 wt% to 2 wt% water-soluble salt which includes a multivalent metal ion.

The term "water-soluble" implies solubility in water. The term water-soluble salt means a salt whose solubility is at least 0.05 g/ 100 g water at 25 °C. The solubility of the salt is preferably greater than 0.1 , more preferably greater than 1 and most preferably greater than 5.

The fluoro alkoxy silane:

While any suitable fluoro alkoxy silane may be used, preferred fluoro alkoxy silanes may be selected from heptadecafluoro-1 ,1 ,2,2-tetrahydrodecyl trimethoxysilane (CAS: 83048-65-1); tridecafluoro-1 ,1 ,2,2-tetrahydrooctyl trimethoxysilane (CAS: 85857-16-5); heptadecafluoro-1 ,1 ,2,2-tetrahydrodecyl triethoxysilane (CAS: 101947-16-4 );

tridecafluoro-1 , 1 , 2, 2-tetrahydrooctyl) triethoxysilane (CAS: 51851-37-7); bis

(tridecafluoro-1 , 1 , 2, 2-tetrahydrooctyl) tetramethyldisiloxane (CAS: 71363-70-7); or bis ((tridecafluoro-1 , 1 ,2, 2-tetrahydrooctyl) dimethylsiloxy) methylsilane (CAS: 521069-00- 1). Such silanes may be purchased from any commercial vendor, such as Gelest Inc.

Heptadecafluoro-1 ,1 ,2,2-tetrahydrodecyl trimethoxysilane (CAS: 83048-65-1), and tridecafluoro-1 , 1 ,2, 2-tetrahydrooctyl trimethoxysilane (CAS: 85857-16-5) are particularly preferred.

The ratio of the water-soluble salt which includes the multivalent metal ion to the fluoro alkoxy silane is from 1 :5 to 5: 1 , preferably 1 : 1 to 2:3. The compositions according to the invention include 0.25 wt% to 5 wt% fluoro alkoxy silane. It was observed that levels of 0.05 wt% showed insignificant repellence, particularly towards oily stains. Thus the compositions include 0.25 wt% to 5 wt% fluoro alkoxy silane, preferably 0.5 wt% to 2 wt%.

Water and alcohol:

The compositions according to the invention are hydro-alcoholic, meaning, that the compositions include water and a Ci to C ₄ alcohol. Preferred compositions may have from about 75 wt% to about 90 wt% alcohol. Preferred alcohols include ethanol, n- propanol and iso-propanol. It is preferred that water is from 5 wt% to 15 wt%. The ratio of water to the alcohol may vary from 1 :6 to 1 :9, without much change in performance.

The compositions may also, preferably, include other common ingredients such as fluorescer, preservatives, perfume, and shading dyes.

Process for making the composition:

In accordance with another aspect, the invention relates to a process for making a composition of the first aspect. The process includes a step of mixing 0.05 parts by weight to 10 parts by weight water-soluble salt having a multivalent metal ion and 0.25 parts by weight to 5 parts by weight fluoro alkoxy silane, with water and a Ci to C ₄ alcohol to get 100 parts of the composition. The ingredients may be mixed in any suitable mixer, and they may be added in any order. It is preferred that water is added to the salt in a container, followed by alcohol, and then the fluoro alkoxy silane. After this, the mixture is preferably mixed in a vortex mixer at room temperature. Method for treating a substrate:

In accordance with another aspect, the invention relates to a method for treating a substrate. The method includes the steps of:

(i) applying a solution, preferably alcoholic solution, of the composition of the first aspect to form a coating on the substrate; and,

(ii) drying the coating. The composition, or a solution thereof, may be sprayed onto the substrate, or the substrate, e.g. fabric may be dipped in the composition, or a solution thereof. Other known methods not particularly mentioned here may also be used.

The compositions of the present invention may be used to treat any given substrate. Preferred substrates include metal, glass, ceramic, fabric and paper. Preferably, the substrate is a fabric, paper or glass. More preferably the substrate is a fabric or glass. The fabric that can be treated includes synthetic as well as natural fabrics. Fabrics may be made of cotton, poly-cotton, polyester, silk or nylon. It is envisaged that the compositions of the present invention can be used to treat garments and other clothing and apparels that form a typical wash-load in household laundry. The household materials that can be treated according to the method of the present invention include, but are not limited to, bedspreads, blankets, carpets, curtains and upholstery. Although the compositions of the present invention are described primarily for treatment of fabrics, it is envisaged that the method may advantageously be used to treat jute, denim and canvass, shoes and jackets.

The method may take 15 to 90 minutes, preferably 20 minutes to an hour. The method may be carried out without any heating or cooling e.g. from 15 °C to 40 °C.

After the treatment, fabrics, in particular, may be squeezed before drying. Treated fabrics may be air dried, sun dried, or dried in a drying machine. It is preferred that fabrics are ironed after drying.

The term "liquor to cloth ratio" or L/C ratio as used herein means the ratio of mass of the solution that is in contact with the fabrics to the mass of the fabrics. The liquor to cloth ratio may be different in each step.

It is preferred that the liquor to cloth ratio is 2 to 100, more preferably 5 to 50, and most preferably from 5 to 20.

The term "area of the fabric contacted" as used herein refers to apparent surface area of any one side of the fabric that is contacted with a solution of the composition. In accordance with a fourth aspect, the invention provides use of a composition of the first aspect for treating a substrate to make it hydrophobic and oleophobic. Use of the composition may help achieve water contact angle greater than 90° and oil contact angle greater than 60°. One skilled in the art would know what contact angle means. The water contact angle is preferably 90° to 180°, more preferably at least 100°, still more preferably at least 1 10°, or even more preferably at least 120°. The contact angle is measured using a sessile drop method immediately after droplet addition.

Kit

In accordance with a fifth aspect the invention provides a kit which includes a composition of the first aspect, along with instructions for use.

Examples

The invention will now be explained in details with the help of non-limiting examples.

Table-1 : Materials used in the experiments

Alcohol Ethanol 99.9%

Salts Aluminium nitrate nonahydrate A.R, Calcium nitrate tetrahydrate

A.R, Zinc nitrate hexahydrate A.R, Copper nitrate trihydrate A.R, Ferric nitrate nonahydrate A.R, Aluminium sulfate hexadecahydrate A.R, Aluminum chloride hexahydrate A.R - all procured from Merck.

Fluoro heptadecafluoro-1 ,1 ,2,2-tetrahydrodecyl trimethoxysilane (CAS:

silane 83048-65-1); tridecafluoro-1 ,1 ,2,2-tetrahydrooctyl

trimethoxysilane (CAS: 85857-16-5);

All the were procured from Gelest Inc.

Substrate Desized cotton ex. Bombay dyeing

Microscopic glass slides - from Blue Star, India Example-1 : Compositions with Al salt (Aluminium nitrate)

Several preferred compositions, and some comparative compositions were made by varying the ratio between the water-soluble salt (Al ³⁺ salt) and the fluoro alkoxy silane. All experiments were conducted with Tridecafluoro-(1 , 1 ,2,2-tetrahydrooctyl) trimethoxy silane. Seven ratios were tried; 1 : 1 , 1 :5, 5: 1 , 1 : 10, 3:5, 4:5 and 10: 1. The formulations were as follows.

Table-2

Notes: 1. In all the compositions, the balance (making up to 100 wt%) was water and ethanol, at ratio of 1 :9.

2. Comp* means composition.

3. Compositions marked with * are comparative compositions.

4. Examples 17*, 18, 19 and 20* were done in a different series of experiments, resulting in slightly different results.

Treatment procedure and measuring contact angles:

Fifty grams of all the compositions 1-20 were taken in separate beakers. Fifty grams ethanol was added to each beaker to get 20 solutions with varying ratios of the salt and the fluoro alkoxy silane. Five hundred μΙ of each of the solution was placed on 100 cm ² swatches of cotton, which were allowed to dry. Once dried, the swatches were ironed and the contact angles of water and oil were measured. These values served as an indication of water and oil repellence of the treated cotton. For glass slides, 100 μΙ of the solution was spread over the glass slides and left to dry for 10 minutes. The surface was wiped with a dry tissue paper to remove any excess solution. The completely dry slides were then checked for water and oil repellence by measuring contact angles.

For comparison, some cotton swatches were treated with only an aqueous solution of the Al ³⁺ salt. Some cotton swatches were treated with an alcoholic solution of only the fluoro alkoxy silane. Some cotton swatches were treated with neat fluoro alkoxy silane. The contact angles of oil and water on such treated cotton were recorded. The values are shown in table-3.

Table-3: Contact angles of water and oil on cotton using ingredients by themselves

Note: In the table-3 (and in other tables that appear elsewhere in this specification), g/l stands for "grams per litre", which indicates concentration of the silane or salt in the solution. When cotton was treated with preferred compositions of table-2, following contact angles were recorded.

Table-4: Contact angles of water and oil on cotton fabric - synergistic effect of Al ³⁺ salt and silane in preferred compositions of table-2

On comparing the contact angles of table-4, i.e. the synergistic data with the contact angles in table-3, it is evident that the preferred compositions showed higher oil and water contact angles. Comparative compositions 6 and 16 showed relatively lower oil contact angles. These compositions had 0.05 wt% fluoro alkoxy silane. Compositions 17 to 20 showed relatively lower oil contact angles, as compared to 1-16, possibly due to the fact that they were done in a different experimental series. However the difference is small. Examples 5, 6, 15, 16, 17 and 20 are outside the claimed range, and show lower oil contact angles, except for 15, which is on the edge of the claimed range and still performs fairly well. For comparison, some glass slides were treated with only an aqueous solution of the Al ³⁺ salt. Some glass slides were treated with an alcoholic solution of only the fluoro alkoxy silane. Some cotton swatches were treated with neat fluoro alkoxy silane. The contact angles of oil and water on such treated glass slides were recorded. The values are shown in table-5.

Table-5: Contact angles of water and oil on glass slides using the ingredients by themselves

When glass slides were treated with preferred compositions of table-2, following contact angles were recorded.

Table-6: Contact angles of water and oil on glass slides - synergistic effect of the Al salt and the fluoro alkoxy silane in preferred compositions of table-2

Composition Water contact angle Oil contact angle code

1 112 76

2 108 73

3 110 78

4 109 70

5 110 70

6* 107 73

7 104 70

8 113 69 10 107 71

1 1 105 64

12 104 74

13 97 72

14 95 72

15 93 75

16* 95 69

Although results indicate that compositions 6 and 16 show higher oil contact angles on glass, but the oil contact angles on fabrics were much lower as indicated in table-4. Therefore, the compositions 6 and 16 may be regarded as comparative compositions. Example-2: Compositions with Fe ³⁺ salt and fluoro alkoxy silane

The experiments conducted in Example-1 were repeated with a Fe ³⁺ salt (Ferric nitrate). Preferred compositions were made by varying the ratio between the Fe ³⁺ salt and the fluoro alkoxy silane (silane). All experiments were conducted with

Tridecafluoro-(1 , 1 ,2,2-tetrahydrooctyl) trimethoxy silane. Table-7 describes the formulations.

Table-7

Note: In all the compositions, the balance (making up to 100 wt%) was water and ethanol, at ratio of 1 :9. Some cotton swatches and some glass slides were treated with only an aqueous solution of the Fe ³⁺ salt. Some cotton swatches and some glass slides were treated with an alcoholic solution of only the fluoro alkoxy silane. Some cotton swatches and some glass slides were treated with neat fluoro alkoxy silane. The contact angles of oil and water on such treated cotton and glass were recorded. The values are shown in table-8 and table-9. Table-8: Contact angles of oil and water on glass - Fe salt and silane by themselves

Table-9: Contact angles of oil on cotton -Fe and silane by themselves

When glass slides and cotton were treated with the preferred compositions of table-7, the observed contact angles were as shown in tables 10 and 11. Table-10: Contact angles of water and oil on glass slides - synergistic effect salt and fluoro alkoxy silane in compositions of table-7

Table-1 1 : Contact angles of oil on cotton - synergistic effect of Fe salt and fluoro alkoxy silane in compositions of table-7

On comparison of the data in tables 10 and 11 , with that of tables 8 and 9, it is evident that the preferred compositions showed higher oil and water contact angles.

Example-3: Experiments with Ca salt (Calcium chloride)

The experiments conducted in Example-1 and 2 were repeated with compositions containing Calcium chloride. Preferred compositions were made by varying the ratio between the Ca ²⁺ salt and the fluoro alkoxy silane. All experiments were conducted with Tridecafluoro-1 ,1 ,2,2-tetrahydrooctyl) trimethoxy silane. The formulations were as follows: Table-12

Note: In all the compositions, the balance (making up to 100 wt%) was water and ethanol, at ratio of 1 :9.

For comparative analysis, some slides were treated with only an aqueous solution of Calcium chloride, while some were treated with only an alcoholic solution of the fluoro alkoxy silane. Some glass slides were treated with neat fluoro alkoxy silane. The contact angles on glass and cotton were as follows:

Table-13: Contact angles of oil and water on glass - Calcium chloride and silane by

themselves

When glass slides were treated with the preferred compositions of table-12, the observed contact angles were as shown in table 14. Table-14: Contact angles of water and oil on glass - synergistic effect of compositions containing Ca ²⁺ salt and fluoro alkoxy silane of table 12

The data in table-14, when compared with that in table-13 shows the synergistic benefits of using a combination of Calcium chloride and a silane. The contact angles were higher when a combination of Ca ²⁺ salt and fluoro alkoxy silane was used.

Example-4: Experiments with Cu salt (Copper sulphate)

The experiments were repeated with compositions containing Copper sulphate and a fluoro alkoxy silane. Preferred compositions were made by varying the ratio between the Cu ²⁺ salt and the fluoro alkoxy silane. All experiments were conducted with Tridecafluoro-(1 , 1 ,2,2-tetrahydrooctyl) trimethoxy silane. Table-15 shows the formulation of preferred compositions:

Table-15

Note: In all the compositions, the balance (making up to 100 wt%) was water and ethanol, at ratio of 1 :9. For comparative analysis, some slides were treated with only an aqueous solution of the salt, while some were treated with only an alcoholic solution of the fluoro alkoxy silane. Some slides were treated with neat fluoro alkoxy silane. The contact angles on glass and cotton were as in table-16. Table-16: Contact angles of oil and water on glass slides - Copper Sulphate and silane by themselves

When glass slides were treated with the preferred compositions of table-15, the observed contact angles were as shown in table 17. Table-17: Synergistic effect of compositions containing Copper sulphate and fluoro alkoxy silane (Compositions of table 15)

Composition Contact angle/water Contact angle/oil

1 c 100 66

3c 107 73

5c 102 69

7c 105 70

9c 99 93

13c 96 74

15c 98 65 The data in table-17, when compared with that in table-16 shows the synergistic benefits of a combination of Copper sulphate and fluoro alkoxy silane. The contact angles were higher when a combination was used.

Example-5: Experiments with Aluminium chloride and Aluminium sulphate

The experiments were repeated with compositions of Aluminium chloride and fluoro alkoxy silane, and another set of compositions which had Aluminium sulphate and a fluoro alkoxy silane. Diluted solutions were used to treat glass surface. After the treatment, contact angles of water and oil were determined.

The formulations were as follows:

Table-18

Experiments on glass slides:

For comparative analysis, some slides were treated with an aqueous solution of the salt and some were treated with an alcoholic solution of the fluoro alkoxy silane. Some slides were treated with neat fluoro alkoxy silane. The contact angles were as in table- 19. Table-19: Contact angle data using only the salt and fluoro alkoxy silane on glass slides

When glass slides were treated with the preferred compositions of table-18, the observed contact angles were as shown in table 20.

Table-20: Contact angles of water and oil on glass slides - synergistic effect of compositions table-18

Composition Contact angle/water Contact angle/oil

2d 101 73

8d 96 74

10d 94 75 14d 91 74

Composition Contact angle/water Contact angle/oil

2e 96 70

8e 97 73

10e 108 70

14e 102 72

The data in table-20, when compared with that in table-19 shows the synergistic effects of using a combination of Aluminium salt and a silane. The contact angles are higher when a combination is used for treating glass surface. Experiments on cotton:

For comparative analysis, some cotton swatches were treated with aqueous solution of the salt and some were treated with an alcoholic solution of the fluoro alkoxy silane. Some slides were treated with neat fluoro alkoxy silane. The contact angles were as follows: Table-21 : Contact angles of only Al ³⁺ salt and the fluoro alkoxy silane on cotton

Data for Aluminium chloride

g/i Contact angle g/i Contact angle

Only silane Only Aluminium chloride

5 12 0.5 12

0.5 10 2 15

1 12 2.5 18

2.5 1 1 10 22

7.5 12 12.5 27

10 20

20 18

Neat 18

Data for Aluminium sulphate

g/i Contact angle g/i Contact angle

Only silane Only Aluminium sulphate

5 12 0.5 12

0.5 10 2 17

1 12 2.5 23

2.5 1 1 10 29 7.5 12 12.5 34

10 20

20 18

neat 18

When cotton swatches were treated with the preferred compositions of table-18, the observed contact angles were as shown in table 22.

Table-22: Contact angles of oil on cotton - synergistic effect of Al salts and silane of compositions of table-18

The data in table-22, when compared with that in table-21 shows the synergistic effects of a combination of Aluminium salt and a silane on cotton on the oil contact angle. The contact angles are higher when a combination is used for treating cotton.

It will be appreciated that the illustrated examples provide for compositions and methods for treating substrates, especially cotton and glass. Treated substrates show higher contact angles against both water and oil. It will also be appreciated that the illustrated examples explain the use of compositions for treating substrates to make it hydrophobic and oleophobic. The illustrated examples also explain that glass and cotton surface treated with preferred compositions show higher oil and water contact angles, as compared to glass and cotton surfaces treated with only a water-soluble salt comprising a multivalent metal ion, or only a fluoro alkoxy silane. It will also be appreciated that preferred compositions provide higher oil and water contact angles while containing lower quantities of a water-soluble salt comprising a multivalent metal ion and a fluoro alkoxy silane. Therefore, the compositions are capable of being effective against aqueous as well as oily stains.

It should be understood that the specific forms of the invention herein illustrated and described are intended to be representative only as certain changes may be made therein without departing from the clear teachings of the disclosure.

Although the invention has been described with reference to specific embodiments, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms.