EP2702130B1

EP2702130B1 - Hard surface treatment composition

Info

Publication number: EP2702130B1
Application number: EP12713139.9A
Authority: EP
Inventors: Somnath Das; Kingshuk Dutta; Amitava Pramanik
Original assignee: Unilever PLC; Unilever NV
Current assignee: Unilever PLC; Unilever NV
Priority date: 2011-04-25
Filing date: 2012-04-04
Publication date: 2015-01-21
Anticipated expiration: 2032-04-04
Also published as: PL2702130T3; EA201301191A1; EA024377B1; AR086478A1; BR112013026942A2; EP2702130A1; ES2535378T3; ZA201307828B; CN103502417A; CN103502417B; WO2012146473A1

Description

Field of the invention

The present invention relates to a composition and a method for treating substrates, in particular hard surfaces, to make the substrate hydrophilic; and for imparting anti-fogging / anti-condensation properties onto said surface.

Background of the invention

Condensation of water onto surfaces, such as bathroom mirrors, glass shower partitions, but also refrigerator and freezer containers, is perceived as annoying by present day consumers.
Without wishing to be bound by a theory it is thought that water that condensates onto hydrophobic surfaces forms tiny water droplets that causes the formation of a fog layer on said surface. This causes fogging on e.g. bathroom mirrors, which is perceived as a nuisance by the consumer. It is thought that making the surface hydrophilic cause water to condensate as a thin film, rather than water droplets, thus not giving the foggy appearance.
Similarly in sub-zero environments, such household freezer devices, seed crystals of ice are formed on surfaces of metals, glass, plastics etc, which tend to grow with time and form a layer of frost, ice or snow-like material.
Surface treatment compositions in the field of ware washing are known. US2008/0274930 discloses ware washing compositions comprising surfactant, an alkalinity source, and corrosion inhibitor; and mentions the use of aluminium III salts, and polymers.
Similarly tooth treatment compositions are known. US5844019 discloses a tooth cleaning composition comprising carboxylic acid, quaternary ammonium salts and aluminium III salts.
The object of the present invention is to provide a composition for rendering a surface less susceptible for vapour deposition.
It is another object to provide for a composition for rendering a surface hydrophilic.
It is yet another object to provide a composition that renders a surface less susceptible to fogging.
It is yet another object to provide a composition that makes surfaces less susceptible to frost deposition in sub-zero conditions
We have found that a composition comprising poly aluminium chloride, a polycarboxylate polymer and a weak acid, when applied to a surface, renders said surface super hydrophilic, thus causing the repellence of small water droplets to provide and anti-fogging effect.

Summary of the invention

Accordingly, in a first aspect, the present invention provides a surface treatment composition comprising 0.05 - 5% of poly aluminium chloride, 0.05 - 5% of a carboxylic polymer, 0.01 - 5% of a weak organic acid, and aqueous liquid; wherein the pH of the composition is between 7 and 9.5; and wherein the PAC : carboxylic polymer ratio is at least 2:5.
Accordingly, in a second aspect, the invention provides a process for treating a substrate (e.g. fabrics, hard surfaces) comprising the steps of treating the substrate with a composition according to the invention, and leaving the substrate to dry.
Accordingly, in a second aspect, the invention provides a bottled cleaning composition comprising the compositions according to the invention.
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.
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

In a first aspect, the invention relates to a composition for treating a surface comprising poly aluminium chloride, poly acrylic acid polymer, a weak organic acid and water; and wherein the pH of the composition is between 7 and 9.5, and wherein the PAC to polymer ratio is at least 2:5.

Poly aluminium chloride

Poly aluminium chloride is a known polyelectrolyte. The poly aluminium chloride (PAC) may be defined as a non-stoichiometric oligomer of aluminium hydroxychloride having general formula [Al(OH)_aCl_b]_n where the value of a is preferably in the range 1.5 to 1.9 and b preferably in the range 1.1 to 1.5, wherein a+b=3. The aluminium content is typically 12-20%.
Commercial PAC may have small amount of impurities including traces of SO₄ ^2-, CO₃ ^2-; NO₃ ^-, Br^-, HCO₃ ^-, and HSO₄ ^-; but such impurities are typically present in a concentration of less than 2%, more preferably less than 1%, still more preferably less than 0.5% or even less than 0.1 % by weight of the PAC.
The PAC is present in the composition in a concentration of between 0.05 - 5% by weight, preferably not more than 4%, more preferably not more than 3%, still more preferably not more than 2.5%, or even less than 2%.

Carboxylic polymer

Preferred carboxylic polymers (or polycarboxylates) are polyacrylates, polymaleates, polyacetates, polyhydroxyacrylates, polyacrylate/polymaleate and polyacrylate/ polymethacrylate copolymers, aminopolycarboxylates and polyacetal carboxylates.
Poly(acrylic acid) or PAA is the most preferred polymer. The monomer of poly(acrylic acid) is acrylic acid. In a water solution at neutral pH, many of the side chains of PAA will lose their protons and acquire a negative charge. PAA is thus understood to be a polymer of repeating units of -[CH2-CH(COOH)]_n-. Preferably the poly acrylic polymers having a molecular weight of at least 1 000 u (u = atomic mass unit, also known as Dalton, D or Da), still more preferably at least 10 000 u, even more preferably at least 100 000 u, but typically not more than 2 000 000 u, or even not more than 1 000 000 u.
The polymer is present in the composition in a concentration of between 0.05 - 5% by weight, preferably not more than 4%, more preferably not more than 3%, still more preferably not more than 2.5%, or even less than 2%.
The PAC : polymer ratio is at least 2:5. Preferably between 2:5 and 20:1, more preferably between 1:1 and 10:1.

Weak organic acid

Preferred organic acids are organic acids selected from, such as di- and tri-carboxylic acids containing β-hydroxy groups, and phenolic acids with ortho-hydroxyls should be considered. Tricarboxylic chelating ligands include but are not limited to citric acid are isocitric acid, aconitic acid, propane-1,2,3-tricarboxylic acid (tricarballylic acid, carballylic acid), trimesic acid. Other examples include gluconic, tartaric, EDTA or their derivatives. Citric acid is the most preferred.
The acid is present in the composition in a concentration of between 0.01 - 5% by weight, preferably the concentration is at least 0.05%, but preferably not more than 4%, more preferably not more than 3%, still more preferably not more than 2.5%, or even less than 2%.

Optional ingredients

Common cleaner adjunct ingredients like perfume, fluorescers and optical brighteners etc may also be included.

Solvents

The composition is preferably an aqueous liquid. However, compositions, wherein the aqueous liquid is a solvent and water mixture, are also contemplated. The solvents are preferably lower alcohols, more preferably methanol, ethanol and/or isopropanol.
Although the presence of solvent is somewhat detrimental to the desired hydrophilicity, the benefit is that the surface dries faster.
Hence the solvent is typically present in the aqueous liquid in a concentration of between 1 and 20%, more preferably between 2 and 10%, more preferably between 3 and 8% by weight of the liquid.

Surface treatment process

The invention provides a process for treating a substrate, comprising the steps in sequence of applying the composition according to the invention to a hard surface and leaving the surface to dry. The surface is preferably not rinsed between these steps.
In a preferred embodiment the surface may be wiped after application of the composition and then be left to dry.
The surface is found to be more hydrophilic after treatment, and thereby less susceptible to deposition of fog or frost.

Product format

The composition may be packaged in the form of any commercially available liquid composition, typically in the form of a bottle containing the liquid.
The composition is preferably applied using a trigger spray applicator. A trigger spray application enables fast and easy use for the consumer and additionally it brings a suitable amount of air into the composition, which aides in the foam formation. Accordingly, the compositions of the invention may be stored in and dispensed by any suitable means, but spray applicators are particularly preferred. Pump dispensers (whether spray or non-spray pumps) are also possible. Thus, the present invention provides a container for a liquid hard surface cleaner, the container comprising a reservoir containing the hard surface cleaning composition of the invention, and spray dispenser for dispensing the composition in the form of a spray. The spray dispenser is preferably a trigger spray but may be any mechanical means for ejecting the liquid in spray or aerosol form.

Examples

The invention will now be explained in details with the help of non-limiting examples.
For all the examples the materials and methods listed herein below were used.

Ingredients:

1. Polyaluminum chloride (commercial grade) Arya PAC from Grasim
2. Polyacrylic acid 450K A.R. (Sigma)
3. Distilled water
4. Aluminum chloride hexahydrate A.R. (Merck)
5. Glass microscopic slides
6. Citric acid monohydrate (Sigma)
7. Sodium hydroxide A.R. (Merck)
8. Ammonia solution A.R. (Merck)

Preparation of the stock solution:

Stock solutions were prepared by mixing 0.5 g/L polyacrylic acid 0.5 g/L PAC in water. To it 0.5 g/L citric acid solution was added. The solution pH was made alkaline to 8.5 using ammonia solution or NaOH solution. 0.5 ml of the solution was applied on the glass substrate, left for 2 minutes and then wiped till dry.

Application to surfaces:

Glass: 25 mm X 75 mm glass microscopic slide was taken. 0.5 mL of the stock solution was applied to glass slide and uniformly spread. The liquid was left on the glass surface for 2 minutes. Then the liquid was wiped off till the glass slides are completely dry. The dry treated glass slides were used for studying the antifog generation.

Antifog:

The treated glass slides were kept in the freezer at -15 C for 10 minutes. The slides were then exposed to hot steam at 100°C for 5 seconds. The fog generated on the glass slides was then analyzed instantly by measuring the transmittance in the visible light in a spectrophotometer (PERKIN Elmer Lambda 900), between 400-700nm. Higher transmittance of a treated glass slide is a measure of less fog generation.

Antifrost:

The treated glass slides were kept in the freezer at -15 C for 10 minutes. The slides were then exposed to room temperature (25°C) for 5 seconds. Then analyzed instantly by measuring the transmittance in the visible light in a spectrophotometer (PERKIN Elmer Lambda 900), between 400-700nm. Higher transmittance of a treated glass slide is a measure of less frost generation.

Example 1: effect of variation in the ratio of the ingredients PAC and PAA

Set1: Stock solutions were prepared by mixing 2.5 g/L polyacrylic acid 0.5 g/L PAC in water. To it 0.5 g/L citric acid solution was added. The solution pH was made alkaline to 8.5 using ammonia solution. 0.5 ml of the solution was applied on the glass substrate, left for 2 minutes and then wiped till dry.
Set2: Stock solutions were prepared by mixing 2.5 g/L polyacrylic acid 1 g/L PAC in water. To it 0.5 g/L citric acid solution was added. The solution pH was made alkaline to 8.5 using ammonia solution. 0.5 ml of the solution was applied on the glass substrate, left for 2 minutes and then wiped till dry.
Set3: Stock solutions were prepared by mixing 0.5 g/L polyacrylic acid 0.5 g/L PAC in water. To it 0.5 g/L citric acid solution was added. The solution pH was made alkaline to 8.5 using ammonia solution. 0.5 ml of the solution was applied on the glass substrate, left for 2 minutes and then wiped till dry.
Set4: Stock solutions were prepared by mixing 1 g/L polyacrylic acid 2.5 g/L PAC in water. To it 0.5 g/L citric acid solution was added. The solution pH was made alkaline to 8.5 using ammonia solution. 0.5 ml of the solution was applied on the glass substrate, left for 2 minutes and then wiped till dry.
Set5: Stock solutions were prepared by mixing 0.5 g/L polyacrylic acid 2.5 g/L PAC in water. To it 0.5 g/L citric acid solution was added. The solution pH was made alkaline to 8.5 using ammonia solution. 0.5 ml of the solution was applied on the glass substrate, left for 2 minutes and then wiped till dry.
Set6: Stock solutions were prepared by mixing 0.5 g/L polyacrylic acid 5 g/L PAC in water. To it 0.5 g/L citric acid solution was added. The solution pH was made alkaline to 8.5 using ammonia solution. 0.5 ml of the solution was applied on the glass substrate, left for 2 minutes and then wiped till dry.

A blank (a) is included for comparison; the blank being a clean, untreated glass slide. The glass slides were kept in the freezer at -15 C for 10 minutes. The slides were then exposed to hot steam at 100°C for 5 seconds. The fog generated on the glass slides was then analyzed instantly by measuring the transmittance in the visible light in a spectrophotometer (PERKIN Elmer Lambda 900), between 400-700nm. Higher transmittance of a treated glass slide is a measure of less fog generation.
Tests with only PAA (set b) and only PAC (set c) were also included as comparative examples.

Results

The transmittance data in the table below show the transparency of the slide. The higher the transmittance, the better the transparency, the lower the transmittance, the more fogging.

		wavelength (nm)
Set No		400	550	700
b	PAA 450 K	77	77	77
1	PAC: PAA 450 K (1: 5)	72	73	73
2	PAC: PAA 450 K (2:5)	90	92	93
3	PAC: PAA 450 K (1: 1)	100	100	100
4	PAC: PAA 450 K (5: 2)	100	99	99
5	PAC: PAA 450 K (5: 1)	100	100	99
6	PAC: PAA 450 K (10: 1)	100	100	100
c	PAC	16	16	16
a	Blank	44	44	45

The results show that PAC and PAA combination in alkaline pH gives higher transmittance. The preferred ratio of PAC and PAA being 2:5 to 10:1.

Example 2: variation in the concentration of PAC and PAA

Set7: Stock solutions were prepared by mixing 1 g/L polyacrylic acid 1 g/L PAC in water. To it 0.5 g/L citric acid solution was added. The solution pH was made alkaline to 8.5 using ammonia solution. 0.5 ml of the solution was applied on the glass substrate, left for 2 minutes and then wiped dry.at 1:1 (v/v) ratio:
- Set 8: Stock solutions were prepared by mixing 0.5 g/L polyacrylic acid 0.5 g/L PAC in water. To it 0.5 g/L citric acid solution was added. The solution pH was made alkaline to 8.5 using ammonia solution. 0.5 ml of the solution was applied on the glass substrate, left for 2 minutes and then wiped dry.
- Set e: Stock solutions were prepared by mixing 0.1 g/L polyacrylic acid 0.1 g/L PAC in water. To it 0.5 g/L citric acid solution was added. The solution pH was made alkaline to 8.5 using ammonia solution. 0.5 ml of the solution was applied on the glass substrate, left for 2 minutes and then wiped dry.
- Set f: Stock solutions were prepared by mixing 0.05 g/L polyacrylic acid 0.05 g/L PAC in water. To it 0.5 g/L citric acid solution was added. The solution pH was made alkaline to 8.5 using ammonia solution. 0.5 ml of the solution was applied on the glass substrate, left for 2 minutes and then wiped dry.

A blank (d) is included for comparison; the blank being a clean, untreated glass slide.
The glass slides were kept in the freezer at -15 C for 10 minutes. The slides were then exposed to hot steam at 100°C for 5 seconds. The fog generated on the glass slides was then analyzed instantly by measuring the transmittance in the visible light in a spectrophotometer (PERKIN Elmer Lambda 900), between 400-700nm. Higher transmittance of a treated glass slide is a measure of less fog generation.

Results

		Wavelength(nm)
Set No.		400	550	700
d	Blank	44	43	44
7	PAC+PAA (1 g/L each)	100	100	100
8	PAC+PAA (0.5 g/L each)	100	100	100
e	PAC+PAA (0.1 g/L each)	69	69	70
f	PAC+PAA (0.05 g/L each)	53	53	53

The results show that the concentration of the PAC and PAA combination in alkaline pH to provide improved transmittance from a concentration of 0.5 g/L each.

Example 3: Effect of mixed solvent system

Set9: Stock solutions were prepared by mixing 0.5 g/L polyacrylic acid 0.5 g/L PAC in water. To it 0.5 g/L citric acid solution was added. The solution pH was made alkaline to 8.5 using ammonia solution. 0.5 ml of the solution was applied on the glass substrate, left for 2 minutes and then wiped till dry.
Set10: Stock solutions were prepared by mixing 0.5 g/L polyacrylic acid 0.5 g/L PAC in 5% ethanol and 95% water. To it 0.5 g/L citric acid solution was added. The solution pH was made alkaline to 8.5 using ammonia solution. 0.5 ml of the solution was applied on the glass substrate, left for 2 minutes and then wiped till dry.
Set11: Stock solutions were prepared by mixing 0.5 g/L polyacrylic acid 0.5 g/L PAC n 20% ethanol and 80% water. To it 0.5 g/L citric acid solution was added. The solution pH was made alkaline to 8.5 using ammonia solution. 0.5 ml of the solution was applied on the glass substrate, left for 2 minutes and then wiped till dry. A blank (g) is included for comparison; the blank being a clean, untreated glass slide. The glass slides were kept in the freezer at -15°C for 10 minutes. The slides were then exposed to hot steam at 100°C for 5 seconds. The fog generated on the glass slides was then analyzed instantly by measuring the transmittance in the visible light in a spectrophotometer (PERKIN Elmer Lambda 900), between 400-700nm. Higher transmittance of a treated glass slide is a measure of less fog generation.

Results

The transmittance data in the table below show the transparency of the slide. The higher the transmittance, the better the transparency, the lower the transmittance, the more fogging.

set no sample Wavelength(nm)

400 550 700

g Blank 46 45 44

9 0% ethanol 99 99 99

10 5% ethanol 98 98 97

11 20% ethanol 90 90 90
The results show that the transmittance of the glass slides decreases as the water to ethanol ratio increases, but provide good transmittance up to 20%.

Example 4: Comparative examples

In this example compositions according to the invention are compared to compositions missing at least one of the required ingredients.

Set12: Stock solutions were prepared by mixing 0.5 g/L polyacrylic acid 0.5 g/L PAC in water. To it 0.5 g/L citric acid solution was added. The solution pH was made alkaline to 8.5 using ammonia solution. 0.5 ml of the solution was applied on the glass substrate, left for 2 minutes and then wiped till dry.
Set13: Stock solutions were prepared by mixing 0.5 g/L polyacrylic acid 0.5 g/L PAC in 5% ethanol and 95% water. To it 0.5 g/L citric acid solution was added. The solution pH was made alkaline to 8.5 using NaOH solution. 0.5 ml of the solution was applied on the glass substrate, left for 2 minutes and then wiped till dry.

Set H-O: Control sets with the absence of one of the ingredients or experimental conditions
The treated glass slides were kept in the freezer at -15 C for 10 minutes. The slides were then exposed to hot steam at 100°C for 5 seconds. The fog generated on the glass slides was then analyzed instantly by measuring the transmittance in the visible light in a spectrophotometer (PERKIN Elmer Lambda 900), between 400-700nm. Higher transmittance of a treated glass slide is a measure of less fog generation.

The compositions are summarised in the table below.

Set no	PAC 0.5 g/L	PAA450K 0.5 g/L	Citric acid 0.5 g/L	pH adjustment
H	Y	N	N	NH3 , 8.5
I	N	Y	N	NH3 , 8.5
J	N	N	Y	NH3 , 8.5
12	Y	Y	Y	NH3 , 8.5
K	Y	Y	N	NH3 , 8.5
L	N	Y	Y	NH3 , 8.5
M	Y	N	Y	NH3 , 8.5
N	Y	Y	Y	INHERENT, 2.0
O	Y	Y	Y	HCl, 4.0
13	Y	Y	Y	NaOH, 8.5

The results in the table below show that the compositions of the invention show superior behaviour to the comparative examples.

Transmittance data:

% transmittance
Set no	at 400 nm	at 550 nm	at 700 nm
H	16	16	9
I	77	78	79
J	54	55	59
12	100	99	99
K	44	44	46
L	81	81	81
M	74	75	75
N	36	37	37
O	64	67	64
13	100	97	93

The results show that the transmittance is the best in the alkaline pH range when PAC and PAA combination is taken. The transmittance is higher when ammonia is used compared to NaOH, thought to be caused by some absorbance of green light by the NaOH near the longer wavelengths.

Example 5: Effect of pH of the formulation on antifogging

Set14: Stock solutions were prepared by mixing 0.5 g/L polyacrylic acid 0.5 g/L PAC in water. To it 0.5 g/L citric acid solution was added. The solution pH was adjusted to 6 using NaOH solution. 0.5 ml of the solution was applied on the glass substrate, left for 2 minutes and then wiped till dry.
Set15: Stock solutions were prepared by mixing 0.5 g/L polyacrylic acid 0.5 g/L PAC in water. To it 0.5 g/L citric acid solution was added. The solution pH was adjusted to 7 using NaOH solution. 0.5 ml of the solution was applied on the glass substrate, left for 2 minutes and then wiped till dry.
Set16: Stock solutions were prepared by mixing 0.5 g/L polyacrylic acid 0.5 g/L PAC in water. To it 0.5 g/L citric acid solution was added. The solution pH was made alkaline to 8.5 using NaOH solution. 0.5 ml of the solution was applied on the glass substrate, left for 2 minutes and then wiped till dry.
Sets P-S: In sets Q to S, stock solutions were prepared by mixing 0.5 g/L polyacrylic acid 0.5 g/L PAC in water. To it 0.5 g/L citric acid solution was added. The solution pH was made acidic to 2,4,5 using HCl solution. 0.5 ml of the solution was applied on the glass substrate, left for 2 minutes and then wiped till dry. Set P is untreated.

The treated glass slides were kept in the freezer at -15 C for 10 minutes. The slides were then exposed to hot steam at 100°C for 5 seconds. The fog generated on the glass slides was then analyzed instantly by measuring the transmittance in the visible light in a spectrophotometer (PERKIN Elmer Lambda 900), between 400-700nm. Higher transmittance of a treated glass slide is a measure of less fog generation.

Wavelength

Set No pH 400 550 700

P Untreated 44 45 46

Q 2 36 37 37

R 4 64 67 64

S 5 62 63 63

14* 6 91 89 87

15 7 100 100 99

16 8.5 100 99 99

* Comparative
The results show that the transmittance increases with increase in the pH of the solutions. The desired pH being 7 and above.

Example 6: Antifrost benefit of the treated glass plates

Set17: Stock solutions were prepared by mixing 0.5 g/L polyacrylic acid 0.5 g/L PAC in water. To it 0.5 g/L citric acid solution was added. The solution pH was made alkaline to 8.5 using ammonia solution. 0.5 ml of the solution was applied on the glass substrate, left for 2 minutes and then wiped till dry.
Set18: Stock solutions were prepared by mixing 0.5 g/L polyacrylic acid 0.5 g/L PAC in water. To it 0.5 g/L citric acid solution was added. The solution pH was made acidic to 2 using HCl solution. 0.5 ml of the solution was applied on the glass substrate, left for 2 minutes and then wiped till dry.
Set19: Stock solutions were prepared by mixing 0.5 g/L polyacrylic acid 2.5 g/L PAC in water. To it 0.5 g/L citric acid solution was added. The solution pH was made alkaline to 8.5 using NaOH solution. 0.5 ml of the solution was applied on the glass substrate, left for 2 minutes and then wiped till dry.

The glass slides were kept in the freezer at -15 C for 10 minutes. The slides were then exposed to room temperature (25°C) for 5 seconds. Then analyzed instantly by measuring the transmittance in the visible light in a spectrophotometer (PERKIN Elmer Lambda 900), between 400-700nm. Higher transmittance of a treated glass slide is a measure of less frost generation.
T is a blank included for comparison; the blank being a clean, untreated glass slide

wavelength (nm)

Set No 400 550 700

T 39 42 36

17 70 72 72

18 53 55 54

19 66 67 68
The results show that the transmittance is higher at alkaline pH with the PAC and PAA combination.

wavelength (nm)

Set No 400 550 700

T 39 42 36

17 70 72 72

18 53 55 54

19 66 67 68

Example 7: Distinction between Al salt and PAC

Set20: Stock solutions were prepared by mixing 0.5 g/L polyacrylic acid 0.5 g/L PAC in water. To it 0.5 g/L citric acid solution was added. The solution pH was made alkaline to 8.5 using ammonia solution. 0.5 ml of the solution was applied on the glass substrate, left for 2 minutes and then wiped till dry.
Set21: Stock solutions were prepared by mixing 0.5 g/L polyacrylic acid 0.5 g/L PAC in water. To it 0.5 g/L citric acid solution was added. The solution pH was made alkaline to 8.5 using NaOH solution. 0.5 ml of the solution was applied on the glass substrate, left for 2 minutes and then wiped till dry.

SetV: Stock solutions were prepared by mixing 0.5 g/L polyacrylic acid 0.5 g/L aluminum chloride hexahydrate in water. To it 0.5 g/L citric acid solution was added. The solution pH was made alkaline to 8.5 using ammonia solution. 0.5 ml of the solution was applied on the glass substrate, left for 2 minutes and then wiped till dry.
SetX: Stock solutions were prepared by mixing 0.5 g/L polyacrylic acid 0.5 g/L aluminum chloride hexahydrate in water. To it 0.5 g/L citric acid solution was added. The solution pH was made alkaline to 8.5 using NaOH solution. 0.5 ml of the solution was applied on the glass substrate, left for 2 minutes and then wiped till dry.
U and W are blank included for comparison; the blank being a clean, untreated glass slide.
The treated glass slides were kept in the freezer at -15°C for 10 minutes. The slides were then exposed to hot steam at 100°C for 5 seconds. The fog generated on the glass slides was then analyzed instantly by measuring the transmittance in the visible light in a spectrophotometer (PERKIN Elmer Lambda 900), between 400-700nm.

Higher transmittance of a treated glass slide is a measure of less fog generation

		Wavelength(nm)
Set No	Sample	400	550	700
U	Untreated	46	44	45	Ammonia
V	Al chloride: PAA (1:1)	86	90	90	Ammonia
20	PAC: PAA (1:1)	99	99	99	Ammonia
W	Untreated	45	44	45	NaOH
X	Al chloride:PAA (1:1)	71	72	73	NaOH
21	PAC: PAA (1:1)	100	97	93	NaOH

The results show that the transmittance is higher when PAC is used with PAA compared to aluminum salt under alkaline conditions (irrespective of the used base), thus providing better antifog benefits.

Claims

A surface treatment composition comprising:
a 0.05 - 5% of poly aluminium chloride,

b 0.05 - 5% of a carboxylic polymer,

c 0.01 - 5% of a weak organic acid, and

d Aqueous liquid;
wherein the pH of the composition is between 7 and 9.5; and wherein the PAC : carboxylic polymer ratio is at least 2:5.
A composition according to claim 1, wherein the polymer is poly acrylic acid.
A composition according to any one of claims 1 or 2, wherein the acid is citric acid.
A composition according to any one of the preceding claims, wherein the PAC:polymer ratio is between 2:5 and 20:1
A composition according to any one of the preceding claims, wherein the aqueous liquid is a solvent and water mixture, comprising of 1-20% solvent
A composition according to claim 5, wherein the solvent is selected from methanol, ethanol and/or isopropanol
A process for treating a substrate (e.g. fabrics, hard surfaces) comprising the steps of:
a treating the substrate with a composition according to anyone of claims 1 to 6, and

b leaving the substrate to dry
A bottled cleaning composition comprising the compositions according to any one of claims 1-6.
A bottle according to claim 8, fitted with a trigger spray dispenser.