DESC:FIELD OF THE INVENTION
[001] The present invention relates to a composition to repair cracks on a wall surface and a method of preparation thereof. More particularly, the present invention provides a quick and easy way of repairing cracks on a wall surface.
BACKGROUND OF THE INVENTION
[002] Non-structural cracks or minor cracks occur in a building after a few days of construction or later due to various reasons (e.g. expansion and contraction of building materials which is caused by a change in temperature and moisture content, etc.).
[003] Conventionally, in order to repair cracks on a wall surface, surface preparation is required i.e. crack that appears on a wall surface are first widened and cleaned of dirt. Then a crack filler is applied like putty, followed by application of paint for a final finish. This process is time consuming and a costly affair. Moreover, application of existing technologies requires separate tools like a putty blade for application and surface finish. Also, mason or skilled labour is required for applying these crack fillers which is a time consuming and expensive process.
[004] Once putty is applied on these cracks, the repaired surface requires curing, drying and levelling to get a smooth finish. Thereafter, paint is applied on the wall surface to blend the repaired patch. This entire process of repairing cracks on a wall surface is not only time consuming but labour intensive as well.
[005] Hence, there is a need of a composition to repair cracks on a wall surface which solves some of the problems of the prior art.

SUMMARY OF THE INVENTION
[006] According to an embodiment of the present invention, there is provided a liquid composition to repair cracks on a wall surface, comprising:
sodium hexametaphosphate in the range of 0.01-0.5%, by weight;
acrylic based dispersing agent in the range of 0.2-2.0%, by weight;
diethylene glycol in the range of 1.0-5.0%, by weight;
polyurethane based thickener in the range of 0.05-3.0%, by weight;
water absorbing polymer in the range of 0.01-0.15%, by weight;
a defoamer in the range of 0.1-1.0%, by weight;
titanium dioxide in the range of 30-50%, by weight;
ethylene oxide condensate of alkyl phenol in the range of 0.05-1.5%, by weight;
an elastomeric acrylic co-polymer dispersion agent in the range of 30-50%, by weight;
a coalescing agent in the range of 1.0-5.0%, by weight;
a rheology modifier in the range of 0.05-0.3%, by weight;
water in the range of 10-20%, by weight; and
cement in the range of 0.1-2.0%.
[007] According to another embodiment of the present invention, there is provided a method for preparing a liquid composition to repair cracks on a wall surface, comprising the steps of:
a) mixing of 10-20% of water, 0.01-0.5% of sodium hexametaphosphate, 1.0-5.0% of diethylene glycol, 0.05-1.5% of ethylene oxide condensate of alkyl phenol, 0.2-2.0% of an acrylic based dispersing agent and 0.05-3.0% of a polyurethane based thickener, by weight of the composition, at a speed of 200-300 rpm to form a mixture;
b) adding, by weight of the composition, 30-50% of titanium oxide, 0.01-0.15% of a water absorbing polymer, 0.1-1.0% of a defoamer and 0.1-2.0% of cement to the mixture of step a) at a speed of 1800-3500 rpm;
c) adding, by weight of the composition, 0.1-1.0% of a preservative, 0.3-1.5% of a biocide, 0.05-3.0% of a polyurethane based thickener, 0.05-0.3% of a rheology modifier, 1.0-5.0% of a coalescing agent and 30-50% of an elastomeric acrylic co-polymer dispersion agent to the mixture of step b) at a speed of 700-900 rpm, to obtain a liquid composition; and
d) mixing the liquid composition at a speed of 1800-3500 rpm and packaging the same ensuring negligible exposure to air during and after packaging.
wherein the cement in the liquid composition is mixed such that the cement does not get mixed with water and does not harden inside the packaging but only hardens after the composition is exposed to air once the composition is applied to cracks on a wall surface.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[008] The embodiments of the present invention eliminate or reduces the aforementioned problems of the prior art by providing a composition to repair cracks especially on a coloured wall surface.
[009] According to an embodiments of the present invention, the liquid composition comprises sodium hexametaphosphate in the range of 0.01-0.5%, by weight, acrylic based dispersing agent in the range of 0.2-2.0%, by weight, diethylene glycol in the range of 1.0-5.0%, by weight, polyurethane based thickener in the range of 0.05-3.0%, by weight. Polyurethane based thickener enables mixing and application of formulation. It further includes a water absorbing polymer in the range of 0.01-0.15%, by weight. This water absorbing polymer acts as a viscosity modifier. The composition’s viscosity is maintained such that it is easily squeezable from a container and it won’t sag when applied on a vertical wall and it will fill the fine cracks. A defoamer which reduces formation of air bubbles is added in the range of 0.1-1.0%, by weight. Titanium dioxide which acts as a whiteness providing pigment, a filler and a pacifier is added in the range of 30-50%, by weight. Ethylene oxide condensate of alkyl phenol acts as a wetting agent and is added in the range of 0.05-1.5%, by weight. An elastomeric acrylic co-polymer dispersion agent which acts as a binder is added in the range of 30-50%, by weight. A coalescing agent which coalesces the solid and liquid components in the formulation in added the range of 1.0-5.0%, by weight. A rheology modifier which avoids product separation in terms of solid - liquid and keeps the formulation uniform in added in the range of 0.05-0.3%, by weight. Cement, grey or white, improves the rheological properties of the mixture and is added in the range of 0.1-2.0%, by weight. It is observed that the wet scrub resistance of the composition with cement is higher than without cement. Water is added in the range of 10-20%, by weight.
[010] In an embodiment, a biocide is added in the composition in the range of 0.3-1.5% and is responsible for post application protection from bacteria and algae.
[011] In an embodiment, a preservative is added in the composition in the range of 0.1-1.0% and enhances the shelf life of the formulation.
[012] In an embodiment, coloured pigment is added in the range of 0.01% - 5% and can be added in a powder form or in a liquid form. When it is used in a liquid form, it is used such that it does not result in setting of the cement.
[013] In an embodiment, the water absorbing polymer can be selected from a group consisting of methyl hydroxyethyl cellulose, hydroxy propyl methyl cellulose, hydroxyethyl cellulose, guar gum, sodium polyacrylate, super absorbent polymers or any other cellulose based product.
[014] In an embodiment, the defoamer is a blend of liquid hydrocarbons with polyglycols.
[015] In an embodiment, the preservative is an isothiazolinone or combination of isothiazolinones.
[016] In an embodiment, the biocide is selected from a group consisting of diuron, carbendazim, isothiazolinones and combinations thereof.
[017] In an embodiment, the coalescing agent is an ester alcohol.
[018] In an embodiment, the rheology modifier is an anionic cross linked acrylic copolymer emulsion.
[019] In another embodiment, the present invention provides a method of preparing a liquid composition to repair cracks on a wall surface comprising mixing of 10-20% of water, 0.01-0.5% of sodium hexametaphosphate, 1.0-5.0% of diethylene glycol, 0.05-1.5% of ethylene oxide condensate of alkyl phenol, 0.2-2.0% of an acrylic based dispersing agent and 0.05-3.0% of a polyurethane based thickener, by weight of the composition, at a speed of 200-300 rpm to form a mixture. In the next step, 30-50% of titanium oxide, 0.01-0.15% of a water absorbing polymer, 0.1-1.0% of a defoamer and 0.1-2.0% of cement are added to the mixture of the first step at a speed of 1800-3500 rpm. Thereafter, 0.1-1.0% of a preservative, 0.3-1.5% of a biocide, 0.05-3.0% of a polyurethane based thickener, 0.05-0.3% of a rheology modifier, 1.0-5.0% of a coalescing agent and 30-50% of an elastomeric acrylic co-polymer dispersion agent are added to the mixture of the second step at a speed of 700-900 rpm, to obtain a liquid composition; and the liquid composition is mixed at a speed of 1800-3500 rpm and packaged ensuring negligible exposure to air during and after packaging. In this method, the cement in the liquid composition is mixed such that the cement does not get mixed with water and does not harden inside the packaging but only hardens after the composition is exposed to air once the composition is applied to cracks on a wall surface.
[020] In an embodiment, the cement does not harden inside the packaging but sets once the composition is applied on the wall surface. Titanium oxide has a small particle size, few microns and therefore has high surface area. The ratio of titanium oxide and water is high, so mixing needs to be done at high speed. Some water will be trapped within titanium oxide particles, due to high surface area. Water is absorbed by polyurethene thickeners and water absorbing polymers. This leave no free water for reaction with cement. So cement lies in the mix as a dispersed powder. Now, when emulsion is added to this mix, due to absence of any air in the packaged form, no water leaves the emulsion to mix with the cement to harden it. Therefore, the cement remains unhardened while in the packaged form.
[021] Post application, in open air, water starts getting released from emulsion, water absorbing polymers etc., which reacts with cement and gives strength to the surface which results in improved wet scrub resistance. Main reason for product hardening as such is not cement’s reaction with water, main reason is release of water from emulsion, which results in film formation (similar to regular paints). The composition once applied on the wall is water resistance.
[022] In an embodiment, at least one pigment is added in step c) in the range of 0.01% to 5%, by weight of the composition.
[023] In a preferred embodiment, anyone can repair the cracks on the wall by themselves and there is no need to call a mason for repairing of cracks thereby saving time and money.
[024] The present invention is a do-it-yourself method of repairing cracks on the wall surface by applying a novel composition. It is a single step solution and doesn’t require any surface preparation. It also does not need any additional tool. Moreover, the present composition shows good elongation (normally no one component cement based product has elongation), which ensures that crack at the same place does not occur in the wall. This is because the product stretches, and not crack, if it experiences internal stresses of the wall and thus ensure that crack does not form again. The present method eliminates the steps of curing, drying and levelling to get a smooth finish and then applying paint over it. Therefore, the present invention is simple, time saving and cost effective.
[025] Advantages and benefits of the embodiments of the present invention, would become more apparent to a person skilled in the art from the below examples.
[026] Example 1: Test results of formulation with and without cement and further addition of Methyl Hydroxy Ethyl Cellulose (MHEC).
Test Without cement With cement With cement and MHEC
Viscosity (cP) 3599 9238 29439
Wet scrub resistance 14798 19925 40000
pH 7 12 12

Observations:
Without cement, viscosity of the formula is very low, which leads to product sagging while applying on walls. Cement acts as low cost viscosity modifier.
• Wet scrub resistance of product is significantly improved due to addition of cement and Methyl Hydroxy Ethyl Cellulose (MHEC).
• The increase in pH as desired is observed only on addition of cement.
Materials Example 1 Example 2
Water 19.35 18.5
Sodium Hexametaphosphate (SHMP) 0.1 0.1
Acrylic based Dispersing agent 1.0 1
Diethylene glycol 3.0 2.5
Polyurethane based Thickner 1.5 1.2
Methyl Hydroxy Ethyl Cellulose (MHEC) 0.1 0.15
Defoamer 0.15 0.3
Titanium Dioxide 34.6 38.5
Ethylene oxide condensate of alkyl phenol 0.8 1.5
Cement 1.0 1.2
Preservative 0.4 0.4
Biocide 0.8 0.85
Elastomeric acrylic co-polymer dispersion or any water based emulsion 35.6 32.5
Coalescing Agent 1.5 1.2
Rheology Modifier 0.1 0.1
Colour pigment 0.1% of the total of the above

[027] Example 2: Following are the characteristics of the formulation:
Test Test Method Followed Results Interpretation
Sheen ASTM D523 9.1 Excellent sheen (blends well with wall paint, gives seamlessness)
Alkali resistance ASTM D6943 Pass Product is compatible with cement based surfaces like plastered walls
Smoothness ISO 4287:1997 1.9 Excellent smoothness (blends well with wall paint, gives seamlessness)
Stain resistance Solutions were prepared of various materials in water and applied on a sample made of the formulation Stain resistance against: Lipstick, crayon, turmeric, permanent marker, ball & gel pens, mud, pencil, ketchup, Pickle, coffee, tea Most household and ink stains can be cleaned completely, without leaving a residue. The test were done for a period of 24 hrs.
Dirt pickup resistance The sample formulation was dusted with fine dust and compared against commercial paint surface Good Very low dirt pick up, maintains the aesthetics
Wet scrub resistance ASTM D2486 Number of cycles: 20000-40000 Excellent wall adhesion
Washability Conventional method Number of cycles: 147 Easily washable with water without any wear and tear
Stability @ high temperature Maintaining the formulation at 50-60deg C for 30-50 days Stable for 50 days @ 55°C Minimum 24 months shelf life
Elongation (%) ASTM D882 169 Dry film has got excellent elasticity. Once crack is filled, it is unlikely that cracks will again appear there. In current multistep solutions, crack often occurs at the same place where filling was done
Tensile Strength (MPA) ASTM D882 3.14 Product has excellent mechanical properties
Brookfield Viscosity (cP) Spindle: (S64)
Temperature: 29degC
RPM: 20 29439 For QC
Opacity IS 101.4.1-1988 White board: 100%
Black board: 100% Excellent in ‘erasing’ the crack
Water permeability RILEM Test Method 11.4 0.3ml water absorbed in 24 hours Excellent resistance to water permeability
Cross-cut adhesion ASTM D3359 Pass

[028] Tests results confirm that this composition can be applied not only on wall surface but this composition can fill and seal cracks present in different types of plastics including HDPE, PPE, LDP, etc., natural and artificial wood and products made thereof. Moreover, gaps between tiles on the floor and on the wall, cracks on artificial or natural marble, ceramics can also be filled.
[029] The foregoing description of specific embodiments of the present invention has been presented for purposes of description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obvious modifications and variations are possible in light of the above teaching.

,CLAIMS:We Claim:
1. A liquid composition to repair cracks on a wall surface, comprising:
sodium hexametaphosphate in the range of 0.01-0.5%, by weight;
acrylic based dispersing agent in the range of 0.2-2.0%, by weight;
diethylene glycol in the range of 1.0-5.0%, by weight;
polyurethane based thickener in the range of 0.05-3.0%, by weight;
water absorbing polymer in the range of 0.01-0.15%, by weight;
a defoamer in the range of 0.1-1.0%, by weight;
titanium dioxide in the range of 30-50%, by weight;
ethylene oxide condensate of alkyl phenol in the range of 0.05-1.5%, by weight;
an elastomeric acrylic co-polymer dispersion agent in the range of 30-50%, by weight;
a coalescing agent in the range of 1.0-5.0%, by weight;
a rheology modifier in the range of 0.05-0.3%, by weight;
water in the range of 10-20%, by weight; and
cement in the range of 0.1-2.0%.
2. The composition as claimed in claim 1, comprising a colour pigment in the range of 0.01% - 5%, by weight.
3. The composition as claimed in claim 1, comprising a preservative in the range of 0.1-1.0%, by weight.
4. The composition as claimed in claim 1, wherein the water absorbing polymer can be selected from a group consisting of methyl hydroxyethyl cellulose, hydroxy propyl methyl cellulose, hydroxyethyl cellulose, guar gum, sodium polyacrylate, super absorbent polymers or any other cellulose based product.
5. The composition as claimed in claim 1, wherein the defoamer is a blend of liquid hydrocarbons with polyglycols.
6. The composition as claimed in claim 1, wherein the preservative is an isothiazolinone or combination of isothiazolinones.
7. The composition as claimed in claim 1, wherein the biocide is selected from a group consisting of diuron, carbendazim, isothiazolinones and combinations thereof.
8. The composition as claimed in claim 1, comprising a biocide in the range of 0.3 to 1.5%, by weight.
9. The composition as claimed in claim 1, wherein the coalescing agent is an ester alcohol.
10. The composition as claimed in claim 1, wherein the rheology modifier is an anionic cross linked acrylic copolymer emulsion.
11. A method of preparing a liquid composition to repair cracks on a wall surface, comprising the steps of:
a) mixing of 10-20% of water, 0.01-0.5% of sodium hexametaphosphate, 1.0-5.0% of diethylene glycol, 0.05-1.5% of ethylene oxide condensate of alkyl phenol, 0.2-2.0% of an acrylic based dispersing agent and 0.05-3.0% of a polyurethane based thickener, by weight of the composition, at a speed of 200-300 rpm to form a mixture;
b) adding, by weight of the composition, 30-50% of titanium oxide, 0.01-0.15% of a water absorbing polymer, 0.1-1.0% of a defoamer and 0.1-2.0% of cement to the mixture of step a) at a speed of 1800-3500 rpm;
c) adding, by weight of the composition, 0.1-1.0% of a preservative, 0.3-1.5% of a biocide, 0.05-3.0% of a polyurethane based thickener, 0.05-0.3% of a rheology modifier, 1.0-5.0% of a coalescing agent and 30-50% of an elastomeric acrylic co-polymer dispersion agent to the mixture of step b) at a speed of 700-900 rpm, to obtain a liquid composition; and
d) mixing the liquid composition at a speed of 1800-3500 rpm and packaging the same ensuring negligible exposure to air during and after packaging.
wherein the cement in the liquid composition is mixed such that the cement does not get mixed with water and does not harden inside the packaging but only hardens after the composition is exposed to air once the composition is applied to cracks on a wall surface.
12. The method as claimed in claim 1, wherein at least one pigment is added in step c) in the range of 0.01% to 5%, by weight of the composition.
Dated this 21st day of November, 2018

For Aditya Birla Science and Technology Company Private Limited
By their Agent

Vrinda Kaul
Reg. No. IN/PA – 2078