FORM 2
THE PATENTS ACT, 1970
(39 OF 1970)
&
THE PATENT RULES, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)
“COATING COMPOSITION AND A PROCESS FOR MAKING THE SAME”
We, Bajaj Electricals Ltd., an Indian National, of, 45/47, Veer Nariman Road, Fort, Mumbai - 400001, Maharashtra, India.
The following specification particularly describes the invention and the manner in which it is to be performed:

FIELD OF INVENTION
The present invention generally relates to the field of coating composition manufacturing. In particular, the present invention provides a method for manufacturing a coating composition for application on a cellulose based substrate.
BACKGROUND OF THE INVENTION
Cellulosic materials such as paper are hydrophilic and tend to lose their form when exposed to humidity and water, affecting their longevity. Ironically, it is this affiliation towards water molecules, and the property of being porous and absorptive which are crucial to multitude of appliances, such as air coolers.
The challenge therefore lies in using cellulosic material for its affinity towards water molecules without allowing the water molecules to damage the material itself. Such damage not only hinders the original form of the material, but also affects its hydrophilicity.
Paper coatings have therefore become an obvious solution to the much-needed issue. Common forms of coatings to increase the life of cellulosic material include: PF resin, epoxy resin, silicone resin, and the like.
A common shortcoming for all the above coatings is that these coatings block the cellulose pores on the surface of the material, leading to reduction of water adsorption and retention, and therefore, reducing the property of the material, leading to lowering its ability to adsorb and retain water.
Thus, there is a need for a coating which is capable of protecting the cellulosic material from deterioration upon coming in contact with water molecules, without compromising the material’s hydrophilic nature. There is therefore a need to overcome at least one of the above-mentioned problems.
SUMMARY OF THE INVENTION
It is to be understood that this disclosure is not limited to the particular embodiments, as there can be multiple possible embodiments which are not expressly illustrated in the present

disclosure. It is also to be understood that the terminology used in the description is for the purpose of describing the particular versions or embodiments only and is not intended to limit the scope of the present invention. This summary is not intended to identify essential features of the claimed subject matter nor is it intended for use in determining or limiting the scope of the claimed subject matter.
In an aspect of the present invention, there is provide a method of preparing a coating composition comprising (a) a material selected from the group consisting of at least a cellulose derivative, at least a clay, and combinations thereof (b) at least a resin; and (c) water, said method comprising the steps of: (a) dispersing cellulose derivative, clay or combinations thereof in water to form a dispersion or a solution; (b) stabilizing the dispersion or solution; (c) mixing at least a resin with water; and (d) contacting the stabilized dispersion or solution with the resin and water mix to obtain a homogenous mix.
In an aspect of the present invention, the resin to water v/v ratio is 1:1 to 1:3.
In another aspect of the present invention, the resin to water v/v ratio is 1:3.
In yet another aspect of the present invention, the cellulose derivative is selected from the group consisting of carboxy methyl cellulose (CMC), hydroxyl ethyl cellulose (HEC), hydroxypropyl cellulose, carboxymethyl cellulose, and combinations thereof.
In yet another aspect of the present invention, the clay is selected from the group consisting of montmorillonite, bentonite, kaolin, hectorite, halloysite, and combinations thereof.
In another aspect of the present invention, the resin is selected from the group consisting of phenolic-formaldehyde resin (P-F resin), melamine-formaldehyde resin (M-F resin), and combinations thereof.
In still another aspect of the present invention, the cellulose derivative weight concentration is in the range of 0.02-1wt%; clay weight concentration is in the range of 0.05-1wt%; and resin weight concentration is in the range of 50-80wt%.
In an aspect of the present invention, the cellulose derivative, clay or combination thereof is dispersed in water for 12-16 hours.

In an aspect of the present invention, the dispersion or solution is stabilized by agitating for 30-45 mins at a speed of 200-800rpm.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1 depicts a honeycomb substrate coated with composition comprising clay particles and resin, in accordance with an embodiment of the present invention.
Figure 2 depicts a honeycomb substrate coated with composition comprising cellulose derivative particles and clay particles mix, and resin, in accordance with an embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Some embodiments of the present disclosure, illustrating all its features, will now be discussed in detail. It must also be noted that as used herein and in the appended claims, the singular forms "a", "an" and "the" include plural references unless the context clearly dictates otherwise. Various modifications to the embodiments will be readily apparent to those skilled in the art and the generic principles herein may be applied to other embodiments. However, one of ordinary skill in the art will readily recognize that the present disclosure for a method of preparing a coating composition is not intended to be limited to the embodiments illustrated but is to be accorded the widest scope consistent with the principles and features described herein.
The present invention provides a method of preparing a coating composition comprising (a) a material selected from the group consisting of at least a cellulose derivative, at least a clay, and combinations thereof (b) at least a resin; and (c) water, said method comprising the steps of: (a) dispersing cellulose derivative, clay or combinations thereof in water to form a dispersion or a solution; (b) stabilizing the dispersion or solution; (c) mixing at least a resin with water; and (d) contacting the stabilized dispersion or solution with the resin and water mix to obtain a homogenous mix.
The resin to water ratio in the method of the present invention is in the range of 1:1-1:3. In an embodiment, the ratio is 1:1. In a preferred embodiment, the ratio is 1:3.

The cellulose derivative is selected from the group consisting of carboxy methyl cellulose (CMC), hydroxyl ethyl cellulose (HEC), hydroxypropyl cellulose, carboxymethyl cellulose, and combinations thereof. In a preferred embodiment, the cellulose derivative is HEC.
The clay is selected from the group consisting of montmorillonite, bentonite, kaolin, hectorite, halloysite, and combinations thereof. In a preferred embodiment, the clay is bentonite.
In a preferred embodiment, a combination of at least a cellulose derivative and at least a clay is dispersed in water to form a dispersion or a solution. In a preferred embodiment, the cellulose derivative is HEC and the clay is bentonite.
The resin is selected from the group consisting of phenolic-formaldehyde resin (P-F resin), melamine-formaldehyde resin (M-F resin), and combinations thereof. In a preferred embodiment, the resin is P-F resin.
The cellulose derivative weight concentration is in the range of 0.02-1wt%; clay weight concentration is in the range of 0.05-1wt%; and resin weight concentration is in the range of 50-80wt%.
The cellulose derivative is dispersed/ soaked in water for 12-16 hours. The clay is dispersed/ soaked in water for 12-16 hours. In a preferred embodiment, the combination of cellulose derivative and clay is dispersed/soaked in water for 12-16 hours. Post dispersing/ soaking, the cellulose derivative, clay or combination thereof is agitated for 30-45 minutes at 200-800rpm. The method further comprises the step of allowing the dispersion or solution to rest for 10-20 minutes.
The coating composition prepared by the method of the present invention can be coated onto a substrate by any conventional method known to a person skilled in the art. The thickness of the coating composition is typically in the micron level, and can be varied as per requirement, which can be commonly derived by a person skilled in the art. In an embodiment, the thickness can be in the range of 1-10µm. In an embodiment, the thickness of the coating on the substrate is uniform. In another embodiment, the thickness of the coating

on the substrate can vary based at least on substrate surface. In an embodiment, the substrate can be a honeycombed evaporative cooling pad for use in air coolers.
The coating composition obtained by the method as described herein is particularly advantageous as it has superior water adsorption capabilities and increases the cooling efficiency of evaporative cooling pads. It also increases the tensile strength and lifespan of the cooling pads.
EXAMPLES
In a particular exemplary working of the present invention, HEC and bentonite is dispersed in 100ml water and allowed to soak for 12-16 hours, post which, the solution is stirred at 200-800 rpm to form a stabilized solution. P-F resin is mixed with water in a 1:3 v/v ratio 200-300prm to obtain a homogenous mix. The stabilized HEC and bentonite solution is mixed with the resin/water mix and homogenized to obtain the coating composition of the present invention.
In another example, bentonite is dispersed in 100ml water and allowed to soak for 12-16 hours, post which, the solution is stirred at 200- 800 rpm to form a stabilized solution. P-F resin is mixed with water in a 1:3 v/v ratio 200-300prm to obtain a homogenous mix. The stabilized HEC and bentonite solution is mixed with the resin/water mix and homogenized to obtain the coating composition of the present invention.
In yet another example, HEC is dispersed in 100ml water and allowed to soak for 12-16 hours, post which, the solution is stirred at 200-800 rpm to form a stabilized solution. P-F resin is mixed with water in a 1:3 v/v ratio 200-300prm to obtain a homogenous mix. The stabilized HEC and bentonite solution is mixed with the resin/water mix and homogenized to obtain the coating composition of the present invention.
As shown in Fig. 1, the composition comprises clay particles (2) distributed in a resin mix (3). The composition is coated on the surface of a substate (1), which can be a honeycombed evaporative cooling pad for use in air coolers.

As shown in Fig. 2, the composition comprises cellulose derivative particles (4) and clay particles (2) distributed in a resin mix (3). The composition is coated on the surface of a substate (1), which can be a honeycombed evaporative cooling pad for use in air coolers.
ADVANTAGES OF THE PRESENT INVENTION
The method of the present invention, particularly the soaking of the cellulose derivative or clay particles with water for a period of 12-16 hours allows for optimum adsorption of water onto the cellulose derivative or clay particles and make it compatible with water (stabilization). This step is also critical to ensure that cloding or agglomeration of the cellulose derivative or clay particles is avoided.
Further, the stirring of the stabilized dispersion/ solution is critical to achieve homogeneity in dispersion of the cellulose derivative or clay particles in the composition and ensure uniform application of the coating composition onto substrate and water absorption.

We claim:
1. A method of preparing a coating composition comprising (a) a material selected from
the group consisting of at least a cellulose derivative, at least a clay, and combinations
thereof (b) at least a resin; and (c) water, said method comprising the steps of:
a. dispersing cellulose derivative, clay or combinations thereof in water to form
a dispersion or a solution;
b. stabilizing the dispersion or solution;
c. mixing at least a resin with water; and
d. contacting the stabilized dispersion or solution with the resin and water mix
to obtain a homogenous mix.
2. The method as claimed in claim 1, wherein the resin to water v/v ratio is 1:1 to 1:3.
3. The method as claimed in claim 1, wherein the resin to water v/v ratio is 1:3.
4. The method as claimed in claim 1, wherein said cellulose derivative is selected from the group consisting of carboxy methyl cellulose (CMC), hydroxyl ethyl cellulose (HEC), hydroxypropyl cellulose, carboxymethyl cellulose, and combinations thereof.
5. The method as claimed in claim 1, wherein said clay is selected from the group consisting of montmorillonite, bentonite, kaolin, hectorite, halloysite, and combinations thereof.
6. The method as claimed in claim 1, wherein said resin is selected from the group consisting of phenolic-formaldehyde resin (P-F resin), melamine-formaldehyde resin (M-F resin), and combinations thereof.

7. The method as claimed in claim 1, wherein cellulose derivative weight concentration is in the range of 0.02-1wt%; clay weight concentration is in the range of 0.05-1wt%; and resin weight concentration is in the range of 50-80wt%.
8. The method as claimed in claim 1, wherein cellulose derivative, clay or combination thereof is dispersed in water for 12-16 hours.
9. The method as claimed in claim 1, wherein the dispersion or solution is stabilized by agitating for 30-45 mins at a speed of 200-800rpm.
10. The method as claimed in claim 9, comprising a subsequent step of allowing the dispersion or solution to rest for 10-20 minutes.