Claims:We Claim:
1. A coating composition comprising-
- resin selected from a group comprising alkoxy terminate silicone modified polyester and hydroxyl terminated branched silicone modified polyester;
- organic titanate selected from a group comprising diisobutoxy-bisethylacetoacetatotitanate and Tetrakis(2-ethylhexyl) titanate;
- solvent;
- catalyst; and
- additive.

2. The composition as claimed in claim 1, wherein the solvent is selected from a group comprising xylene, butanol, dichloromethane, methyl isobutyl ketone (MIBK), methyl ethyl ketone (MEK) and any combination thereof.

3. The composition as claimed in claim 1, wherein the catalyst is triethylamine.

4. The composition as claimed in claim 1, wherein the additive is selected from a group comprising corrosion inhibitor, wetting agent, crosslinking agent, stabilizing agent, and any combination thereof.

5. The composition as claimed in claim 4, wherein the corrosion inhibitor is zinc sulfonate based.

6. The composition as claimed in claim 4, wherein the wetting agent is selected from a group comprising polyether modified siloxane and organo-modified siloxane.

7. The composition as claimed in claim 4, wherein the crosslinking agent is selected from a group comprising tris (alkoxycarbonyl amino)triazine and tris(4-aminophenyl)-1,3,5-triazine.

8. The composition as claimed in claim 4, wherein the stabilizing agent is selected from a group comprising ethyl acetoacetate and acetyl acetonate.

9. The composition as claimed in claim 1, wherein the resin is in an amount ranging from about 20 wt% to 40 wt%.
10. The composition as claimed in claim 1, wherein the organic titanate is in an amount ranging from about 1 wt% to 5 wt%.

11. The composition as claimed in claim 1, wherein the catalyst is in an amount ranging from about 0.1 wt% to 1 wt%.

12. The composition as claimed in claim 1, wherein the solvent is in an amount ranging from about 10 wt % to 50 wt%.

13. The composition as claimed in claim 1, wherein the additive is in an amount ranging from about 0.2 wt% to 5 wt%.

14. The composition as claimed in claim 2, wherein the solvent selected from a group comprising xylene, butanol, methyl isobutyl ketone, methyl ethyl ketone, and any combination thereof, is in an amount ranging from about 10 wt% to 20 wt%.

15. The composition as claimed in claim 2, wherein the dichloromethane is in an amount ranging from about 30 wt% to 50 wt%.

16. The composition as claimed in claim 4, wherein the corrosion inhibitor is in an amount ranging from about 0.5 wt% to 3 wt%; the wetting agent is in an amount ranging from about 0.2 wt% to 1 wt%; the crosslinking agent is in an amount ranging from about 1.5 wt% to 5 wt%; and the stabilizing agent is in an amount ranging from about 0.4 wt% to 1 wt%.

17. The composition as claimed in claim 1, wherein the composition has pH ranging from about 6 to 8.

18. The composition as claimed in claim 1, wherein the composition has specific gravity ranging from about 1.05 to 1.15.

19. The composition as claimed in claim 1, wherein the composition has viscosity ranging from about 70 cps and 100 cps.

20. The composition as claimed in claim 1, wherein the composition has non-volatile matter ranging from about 25% to 40%.

21. The composition as claimed in claim 4, wherein the composition comprises the alkoxy terminated silicone modified polyester, the organic titanate, the solvent, the corrosion inhibitor, the wetting agent and the catalyst.

22. The composition as claimed in claim 4, wherein the composition comprises the hydroxyl terminated branched silicone modified polyester, the organic titanate, the solvent, the corrosion inhibitor, the wetting agent, the crosslinking agent, the catalyst and the stabilizing agent.

23. A method of preparing the coating composition as claimed in claim 1, said method comprises-
- mixing the resin and the solvent to obtain mixture-A;
- mixing the organic titanate and the solvent, optionally along with the stabilizing agent to obtain mixture-B; and
- mixing the mixture-A and the mixture-B, followed by adding the additive and mixing to obtain the composition.

24. The method as claimed in claimed 23, wherein the mixture-A is obtained by mixing the resin and the solvent selected from a group comprising xylene, butanol, methyl isobutyl ketone, methyl ethyl ketone, and any combination thereof, at high shear mixing for a duration ranging from about 20 minutes to 30 minutes.

25. The method as claimed in claim 23, wherein the mixture-B is obtained by mixing the organic titanate and the solvent selected from a group comprising dichloromethane, while purging nitrogen, followed by stirring for a duration ranging from about 5 hours to 6 hours.

26. The method as claimed in claim 23, wherein the mixture-B is obtained by mixing the organic titanate and the solvent selected from a group comprising dichloromethane, followed by adding stabilizing agent and mixing, while purging nitrogen, followed by stirring for a duration ranging from about 5 hours to 6 hours.

27. The method as claimed in claim 23, wherein step of mixing the mixture-A and the mixture-B comprises-
- adding the mixture-A to the mixture-B, followed by stirring for a duration ranging from about 10 minutes to 15 minutes and adding catalyst, followed by mixing; and adding the corrosion inhibitor and the wetting agent under high shear mixing for a duration ranging from about 10 minutes to 15 minutes; or
- adding the mixture-A to the mixture-B, followed by stirring for a duration ranging from about 10 minutes to 15 minutes and adding the crosslinking agent and the catalyst, followed by mixing; and adding the corrosion inhibitor and the wetting agent under high shear mixing for a duration ranging from about 10 minutes to 15 minutes.

28. An article coated with the composition as claimed in claim 1.

29. The article as claimed in claim 28, wherein the article is selected from a group comprising galvanized metal, hot rolled metal and galvalume.

30. The article as claimed in claim 28, wherein the coating has dry film thickness ranging from about 8 µm to 20 µm.

31. The article as claimed in claim 28, wherein the article is resistant to impact energy ranging from about 11 joules to 15 joules.

32. The article as claimed in claim 28, wherein the article is resistant to corrosion ranging from about 96 hours to 120 hours according to salt spray test.

33. The article as claimed in claim 28, wherein the composition has highest level of adhesion with the article, having ASTM D 3359-09 about 5B according to cross hatch adhesion test.

34. A method of producing the article as claimed in claim 28, said method comprises- coating a substrate with the composition as claimed in claim 1, followed by curing to obtain the article.

35. The method as claimed in claim 34, wherein the coating is carried out by technique selected from a group comprising spray coating, dip coating, roll coating, wiping method and any combination thereof.

36. The method as claimed in claim 34, wherein the curing is carried out at a temperature ranging from about 140 ºC to 250 ºC, for a duration ranging from about 10 to 15 minutes.

37. A method of coating a substrate with the composition as claimed in claim 1 for obtaining corrosion resistant substrate, wherein the coating is carried out by technique selected from a group comprising spray coating, dip coating, roll coating, wiping method and any combination thereof

38. The method as claimed in claim 37, wherein the method comprises curing coated substrate at a temperature ranging from about 140 ºC to 250 ºC, for a duration ranging from about 10 to 15 minutes.

39. The method as claimed in claim 37, wherein the obtained coated substrate is resistant to corrosion > 96 hours according to salt spray test.

40. The method as claimed in claim 37, wherein the substrate is selected from a group comprising galvanized metal, hot rolled metal and galvalume.

, Description:TECHNICAL FIELD
The present disclosure relates to field of material science. The present disclosure particularly relates to transparent coating composition and method of preparation thereof. The coating composition provides for improved adhesion and improved resistance to corrosion. The disclosure further relates to an article coated with said coating composition and method of preparation thereof. The disclosure also relates to method of coating a substrate with said coating composition to obtain substrate having improved corrosion resistance.

BACKGROUND OF THE DISCLOSURE
Hot rolled (HR) metal either in circular, square or rectangular hollow section and other metallic substrates are highly susceptible to humid and open environment, thereby susceptible to high red rusting. The construction segment where hot rolled tubes are used in structural applications need rust free materials before they are subjected to processing, such as painting and degreasing.

In order to avoid rusting in-line of the hot rolled metal and the metallic substrate, diluted or concentrated coolant and oil are employed. However, use of coolant and oil provided undesired result in terms of rust protection for rolling and handling conditions that resulted in rejection of HR tubes. Further, coated metallic substrates were developed that can provide foundation for further coatings directly with desired rust prevention. However, developing coated metallic substrates, such as coated tubes was not economical and it was noted that such coated metallic substrates were found to be not feasible to the line conditions because of the bulk flow of the coolant, required for cooling the tubes in processing from flat sheet of tubes.

Thus, there was a need for developing a coating composition which is economical and fulfils the desired properties of coated samples in terms of adherence on non-degreased surface, rust prevention, welding parameters and in-can properties in terms of coolant immiscibility, transparency, low viscosity and low specific gravity. The present disclosure describes a coating composition that is economical and fulfils above mentioned described properties.

STATEMENT OF THE DISCLOSURE
Accordingly, the present disclosure relates to a coating composition comprising- resin selected from a group comprising alkoxy terminate silicone modified polyester and hydroxyl terminated branched silicone modified polyester; organic titanate selected from a group comprising diisobutoxy-bisethylacetoacetatotitanate and Tetrakis(2-ethylhexyl) titanate; solvent; catalyst; and additive. The coating composition is economical and provides for improved rust prevention or corrosion resistance. Additionally, the coating composition demonstrates improved properties in terms of low specific gravity, low viscosity, improved adhesion to the substrate.

The present disclosure further relates to a method of preparing the coating composition described above, said method comprises:
- mixing the resin and the solvent to obtain mixture-A;
- mixing the organic titanate and the solvent, optionally along with the stabilizing agent to obtain mixture-B; and
- mixing the mixture-A and the mixture-B, followed by adding the additive and mixing to obtain the composition.

The present disclosure further relates to article coated with the coating composition. The article is resistant to corrosion and resistant to impact energy ranging from about 11 joules to 15 joules.

The present disclosure further relates to method of producing the article, said method comprises coating a substrate with the composition described above, followed by curing to obtain the article.

The present disclosure further relates to method of coating a substrate with the composition described above for obtaining corrosion resistant substrate, wherein the coating is carried out by technique selected from a group comprising spray coating, dip coating, roll coating, wiping method any combination thereof.

DETAILED DESCRIPTION OF THE DISCLOSURE
Unless otherwise defined, all terms used in the disclosure, including technical and scientific terms, have meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. By means of further guidance, term definitions are included for better understanding of the present disclosure.

As used herein, the singular forms ‘a’, ‘an’ and ‘the’ include both singular and plural referents unless the context clearly dictates otherwise.

The term ‘comprising’, ‘comprises’ or ‘comprised of’ as used herein are synonymous with ‘including’, ‘includes’, ‘containing’ or ‘contains’ and are inclusive or open-ended and do not exclude additional, non-recited members, elements or method steps.

The recitation of numerical ranges by endpoints includes all numbers and fractions subsumed within the respective ranges, as well as the recited endpoints.

The term ‘about’ as used herein when referring to a measurable value such as a parameter, an amount, a temporal duration, and the like, is meant to encompass variations of ±10% or less, preferably ±5% or less, more preferably ±1% or less and still more preferably ±0.1% or less of and from the specified value, insofar such variations are appropriate to perform the present disclosure. It is to be understood that the value to which the modifier ‘about’ refers is itself also specifically, and preferably disclosed.

Reference throughout this specification to ‘some embodiments’, ‘one embodiment’ or ‘an embodiment’ means that a particular feature, structure or characteristic described in connection with the embodiment may be included in at least one embodiment of the present disclosure. thus, the appearances of the phrases ‘in some embodiments’, ‘in one embodiment’ or ‘in an embodiment’ in various places throughout this specification may not necessarily all refer to the same embodiment. It is appreciated that certain features of the disclosure, which are for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the disclosure, which are, for brevity described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination.

The present disclosure describes a coating composition with improved coating properties. The coating composition provides for improved corrosion resistance to substrate, demonstrates improved adhesion to the substrate.

In an embodiment, the coating composition has low viscosity and low specific gravity.

In an embodiment, the coating composition is transparent in nature.

In an embodiment, the coating composition comprises:
- resin selected from a group comprising alkoxy terminate silicone modified polyester and hydroxyl terminated branched silicone modified polyester;
- organic titanate selected from a group comprising diisobutoxy-bisethylacetoacetatotitanate and Tetrakis(2-ethylhexyl) titanate;
- solvent,
- catalyst, and
- additive.

In some embodiments of the present disclosure, the resin is in an amount ranging from about 20 wt% to 40 wt%, including all the values in the range, for instance, 21 wt%, 22 wt%, 23 wt%, 24 wt% and so on and so forth.

In some embodiments of the present disclosure, the organic titanate is in an amount ranging from about 1 wt% to 5 wt%, including all the values in the range, for instance, 1.1 wt%, 1.2 wt%, 1.3 wt%, 1.4 wt% and so on and so forth.

In some embodiments of the present disclosure, the solvent is selected from a group comprising xylene, butanol, dichloromethane, methyl isobutyl ketone (MIBK), methyl ethyl ketone (MEK) and any combination thereof.

In some embodiments of the present disclosure, the solvent is in an amount ranging from about 10 wt % to 50 wt%, including all the values in the range, for instance, 11 wt%, 12 wt%, 13 wt%, 14 wt% and so on and so forth.

In some embodiments of the present disclosure, the solvent selected from a group comprising xylene, butanol, methyl isobutyl ketone, methyl ethyl ketone, and any combination thereof, is in an amount ranging from about 10 wt% to 20 wt%, including all the values in the range, for instance, 11 wt%, 12 wt%, 13 wt%, 14 wt% and so on and so forth.

In some embodiments of the present disclosure, the solvent, such as dichloromethane is in an amount ranging from about 30 wt% to 50 wt%, including all the values in the range, for instance, 31 wt%, 32 wt%, 33 wt%, 34 wt% and so on and so forth.

In some embodiments of the present disclosure, the catalyst includes but it is not limited to triethylamine.
In some embodiments of the present disclosure, the catalyst is in an amount ranging from about 0.1 wt% to 1 wt%, including all the values in the range, for instance, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt% and so on and so forth.

In some embodiments of the present disclosure, the additive is selected from a group comprising corrosion inhibitor, wetting agent, crosslinking agent, stabilizing agent, and any combination thereof.

In some embodiments of the present disclosure, the additive is in an amount ranging from about 0.2 wt% to 5 wt%, including all the values in the range, for instance, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt% and so on and so forth.

In some embodiments of the present disclosure, the corrosion inhibitor includes but it is not limited to zinc sulfonate based. In an embodiment, the zinc sulfonate based corrosion inhibitor is selected from a group comprising Nacorr 1552 (zinc salt of an aromatic sulfonic acid; solvent- 2-Butoxyethanol) and Nacorr 1551 (zinc salt of an aromatic sulfonic acid; solvent- mineral spirits). In an embodiment, zinc sulfonate based corrosion inhibitor provides for wet-on-wet adhesion of the composition. This property of the zinc sulfonate based corrosion inhibitor provides for adhesion of the composition on non-degreased surface.

In some embodiments of the present disclosure, the corrosion inhibitor is in an amount ranging from about ranging from about 0.5 wt% to 3 wt%, including all the values in the range, for instance, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt% and so on and so forth.

In some embodiments of the present disclosure, the wetting agent is selected from a group comprising polyether modified siloxane and organo-modified siloxane. In an embodiment, the organo-modified siloxane includes but it is not limited to poly trialkyl siloxane with polyether moieties.

In some embodiments of the present disclosure, the wetting agent is in an amount ranging from about 0.2 wt% to 1 wt%, including all the values in the range, for instance, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt% and so on and so forth.

In some embodiments of the present disclosure, the crosslinking agent is selected from a group comprising tris (alkoxycarbonyl amino)triazine and tris(4-aminophenyl)-1,3,5-triazine and combination thereof.

In some embodiments of the present disclosure, the crosslinking agent is in an amount ranging from about 1.5 wt% to 5 wt%, including all the values in the range, for instance, 1.6 wt%, 1.7 wt%, 1.8 wt%, 1.9 wt% and so on and so forth.

In some embodiments of the present disclosure, the stabilizing agent is selected from a group comprising ethyl acetoacetate, acetyl acetonate and combination thereof.

In an embodiment, the stabilizing agent is in an amount ranging from about 0.4 wt% to 1 wt%, including all the values in the range, for instance, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt% and so on and so forth.

In some embodiments of the present disclosure, the composition comprises the alkoxy terminated silicone modified polyester, the organic titanate, the solvent, the corrosion inhibitor, the wetting agent and the catalyst.

In some embodiments of the present disclosure, the coating composition comprises the alkoxy terminated silicone modified polyester, the organic titanate, such as Tetrakis(2-ethylhexyl) titanate, the solvent, the corrosion inhibitor, the wetting agent, catalyst and stabilizing agent.

In some embodiments of the present disclosure, the coating composition comprises the hydroxyl terminated branched silicone modified polyester, the organic titanate, the solvent, the corrosion inhibitor, the wetting agent, the crosslinking agent and the catalyst.

In some embodiments of the present disclosure, the coating composition comprises the hydroxyl terminated branched silicone modified polyester, the organic titanate, such as Tetrakis(2-ethylhexyl) titanate, the solvent, the corrosion inhibitor, the wetting agent, catalyst, cross linking agent and stabilizing agent.

In an exemplary embodiment, the coating composition comprises- about 20 wt% to 40 wt% of alkoxy terminated silicon modified polyester, about 10 wt % to 20 wt% of xylene, about 30 wt% to 50 wt% of dichloromethane, about 10 wt% to 20 wt% of methyl isobutyl ketone, about 0.5 wt% to 3 wt% of zinc sulfonate based inhibitor, about 0.5 wt% to 1 wt% of non-flourine based organo-modified siloxane, about 0.15 wt% to 1 wt% of triethyl amine and about 1wt% to 5 wt% of Diisobutoxy-bisethylacetoacetatotitanate.

In another exemplary embodiment, the coating composition comprises- about 20 wt % to 40 wt% of hydroxyl terminated branched silicone modified polyester, about 10 wt% to 20 wt% of butanol, about 30 wt% to 50 wt% of dichloromethane, about 10 wt% to 20 wt% of methyl ethyl ketone, about 0.5 wt% to 3 wt% of zinc sulfonate based inhibitor, about 0.5 wt% to 1 wt% of polyether modified siloxane, about 1.5 wt% to 5 wt% of formaldehyde free tris(alkoxylcarbonyl amino)triazine, about 0.15 wt% to 1 wt% of triethyl amine, about 0.4 wt% to 1 wt% of ethyl acetoacetate and about 1 wt% to 5 wt% of Tetrakis(2-ethylhexyl) titanate.

In some embodiments of the present disclosure, the coating composition has pH ranging from about 6 to 8, including all the values in the range, for instance, 6.1, 6.2, 6.3, 6.4 and so on and so forth.

In some embodiments of the present disclosure, the coating composition has viscosity ranging from about 70 cps to 100 cps, including all the values in the range, for instance, 71 cps, 72 cps, 73 cps, 74 cps and so on and so forth.

In some embodiments of the present disclosure, the coating composition has non-volatile matter ranging from about 25% to 40%, including all the values in the range, for instance, 26%, 27%, 28%, 29% and so on and so forth.

In some embodiments of the present disclosure, the coating composition has specific gravity ranging from about 0.15 to 1.15, including all the values in the range, for instance, 0.16, 0.17, 0.18, 0.19 and so on and so forth.

The present disclosure further relates to method of preparing the coating composition described above.

In some embodiments of the present disclosure, the method of preparing the coating composition comprises:
- mixing the resin and the solvent to obtain mixture-A;
- mixing the organic titanate and the solvent, optionally along with the stabilizing agent to obtain mixture-B; and
- mixing the mixture-A and the mixture-B, followed by adding the additive and mixing to obtain the composition.

In some embodiments of the present disclosure, the mixture-A is obtained by mixing the resin and the solvent selected from a group comprising xylene, butanol, methyl isobutyl, ketone, and any combination thereof. In an embodiment, the mixing is carried out by high shear mixing for a duration ranging from about 20 minutes to 30 minutes, including all the values in the range, for instance, 21 minutes, 22 minutes, 23 minutes, 24 minutes and so on and so forth.

In some embodiments of the present disclosure, the mixture-B is obtained by mixing the organic titanate, such as diisobutoxy-bisethylacetatotitante and the solvent including but it is not limited to dichloromethane while purging nitrogen, followed by stirring for a duration ranging from about 5 hours to 6 hours, including all the values in the range, for instance, 5.1 hours, 5.2 hours, 5.3 hours, 5.4 hours and so on and so forth. In an embodiment, during mixing, the nitrogen purging is carried out for creating moisture free atmosphere so that sedimentation is prevented. In an embodiment, obtained mixture-B is subjected to holding time ranging from about 20 hours to 24 hours for allowing the mixture-B to be stabilized.

In some embodiments of the present disclosure, the mixture-B is obtained by mixing the organic titanate, such as Tetrakis(2-ethylhexyl) titanate and solvent including but it is not limited to dichloromethane, followed by adding the stabilizing agent and mixing, while purging nitrogen, followed by stirring for a duration ranging from about 5 hours to 6 hours, including all the values in the range, for instance, 5.1 hours, 5.2 hours, 5.3 hours, 5.4 hours and so on and so forth. In an embodiment, during mixing, the nitrogen purging is carried out for creating moisture free atmosphere so that sedimentation is prevented. In an embodiment, obtained mixture-B is subjected to holding time ranging from about 20 hours to 24 hours for allowing the mixture-B to be stabilized.

In some embodiments of the present disclosure, the mixing of the mixture-A and the mixture-B comprises- adding the mixture-A to the mixture-B while stirring the mixture-B, followed by stirring the whole mixture for a duration ranging from about 10 minutes to 15 minutes, including all the values in the range, for instance, 10.1 minutes, 10.2 minutes, 10.3 minutes, 10.4 minutes and so on and so forth. Post completing the stirring, the catalyst is added under mixing, followed by adding the corrosion inhibitor and the wetting agent under high shear mixing for a duration ranging from about 10 minutes to 15 minutes, including all the values in the range, for instance, 10.1 minutes, 10.2 minutes, 10.3 minutes, 10.4 minutes and so on and so forth.

In some embodiments of the present disclosure, the mixing of the mixture-A and the mixture-B comprises- adding the mixture-A to the mixture-B while stirring the mixture-B, followed by stirring the whole mixture for a duration ranging from about 10 minutes to 15 minutes, including all the values in the range, for instance, 10.1 minutes, 10.2 minutes, 10.3 minutes, 10.4 minutes and so on and so forth. Post completing the stirring, the crosslinking agent and the catalyst are added under mixing, followed by adding the corrosion inhibitor and the wetting agent under high shear mixing for a duration ranging from about 10 minutes to 15 minutes, including all the values in the range, for instance, 10.1 minutes, 10.2 minutes, 10.3 minutes, 10.4 minutes and so on and so forth.

In an exemplary embodiment, the method of preparing the coating composition comprises:
- mixing about 20 wt% to 40 wt% of the alkyl terminated silicone modified polyester or the hydroxyl terminated silicone modified branched polyester with about 10 wt% to 20 wt% of the solvent selected from a group comprising xylene, butanol, dichloromethane, methyl isobutyl ketone (MIBK), methyl ethyl ketone (MEK) and any combination thereof, followed by high shear mixing for a duration ranging from about 20 minutes to 30 minutes to obtain mixture-A. In an embodiment, if hydroxyl terminated branched silicone modified polyester is employed, then solvents, such as butanol, MEK and butanol are employed. In an embodiment, if alkoxy terminated silicon modified polyester is employed, then solvent, such as xylene and MIBK are employed.
- mixing about 1 wt% to 5 wt% of the diisobutoxy-bisethylacetatotitante or tetrakis (2-ethylhexyl)titanate with about 30 wt% to 50 wt% of the solvent such as dichloromethane while purging nitrogen, followed by stirring for a duration ranging from about 5 hours to 6 hours to obtain mixture-B and holding the mixture-B for about 24 hours to stabilize the mixture. In an embodiment, if tetrakis (2-ethylhexyl)titanate is employed, then about 0.4 wt% to 1 wt% of the stabilizing agent, such as ethyl acetoacetate and acetyl acetonate is added.
- adding mixture-A to mixture-B while stirring mixture B and continuing stirring for a duration ranging from about 10 minutes to 15 minutes, followed by adding about 0.15 wt% to 1 wt% of the catalyst, such as triethyl amine to catalyze the reaction. Further, adding about 0.5 wt% to 3 wt% of the zinc sulfonate based corrosion inhibitor and about 0.2 wt% to 1 wt% of the stabilizing agent, such as polyether modified siloxane and organo modified siloxane, followed by high shear mixing for a duration ranging from about 10 minutes to 15 minutes to obtain the coating composition. In an embodiment, if hydroxyl terminated silicone modified branched polyester is employed in mixture-A, then crosslinking agent, such as tris (alkoxycarbonyl amino)triazine and tris(4-aminophenyl)-1,3,5-triazine is added prior to addition of the corrosion inhibitor and the stabilizing agent.

The present disclosure further relates to an article comprising the coating composition described above.

In an embodiment, the article is coated with the coating composition described above.

In some embodiments of the present disclosure, the article includes but it is not limited to galvanized metal, hot rolled metal and galvalume.

In some embodiments of the present disclosure, the coating on the article has dry film thickness ranging from about 8 µm to 20 µm, including all the values in the range, for instance, 8.1 µm, 8.2 µm, 8.3 µm, 8.4 µm and so on and so forth.

In some embodiments of the present disclosure, the article is resistant to impact energy ranging from about 11 joules to 15 joules, including all the values in the range, for instance, 11.1 joules, 11.2 joules, 11.3 joules, 11.4 joules.

In some embodiments of the present disclosure, the article is resistant to corrosion for at least 96 hours, according to salt spray test. In an embodiment, the article is resistant to corrosion for about 96 hours to 120 hours, including all the values in the range, for instance, 97 hours, 98 hours, 99 hours, 100 hours and so on and so forth.

In some embodiments of the present disclosure, the coating composition has highest level of adhesion with the article, having ASTM D 3359-09 about 5B, according to cross hatch adhesion test.

In an embodiment of the present disclosure, the article coated with the coating composition demonstrates improved resistance to corrosion. In an embodiment, the article shows improved salt resistance.

In an embodiment of the present disclosure, the article coated with the coating composition does not require processing or pre-treatment, such as degreasing and phosphating, and the article is directly paintable. In an embodiment, the painting on the article coated with the coating composition provides for improved resistance to impact energy ranging from about 11 joules to 15 joules and improved adhesion.

In an embodiment of the present disclosure, the article coated with the coating composition can be used in plumbing section, structural and maintenance segment in view of the improved resistance to corrosion and improved resistance to impact energy demonstrated by the article and allowing improved adhesion of the paint to the article.

The present disclosure further relates to a method of producing the article.

In an embodiment of the present disclosure, the method of producing the article comprises, coating a substrate with the coating composition described above, followed by curing to obtain the article coated with the composition.

In some embodiments of the present disclosure, the substrate includes but it is not limited to galvanized metal, hot rolled metal and galvalume.

In some embodiments of the present disclosure, the coating is carried out by technique selected from a group comprising spray coating, dip coating, roll coating, wiping method and any combinations thereof.

In some embodiments of the present disclosure, the curing is carried out at a temperature ranging from about 140 ºC to 250 ºC, including all the values in the range, for instance, 141 ºC, 142 ºC, 143 ºC, 144 ºC and so on and so forth. In an embodiment, the curing is carried out for a duration ranging from about 10 minutes to 15 minutes, including all the values in the range, for instance, 11 minutes, 12 minutes, 13 minutes, 14 minutes and so on and so forth.

In an embodiment of the present disclosure, the article obtained upon curing showcases excellent salt resistance for at least 96 hours, according to salt spray test. Additionally, the coating in the article shows improved surface tolerance and adherent film (5B) on non-degreased surface.

In an embodiment of the present disclosure, the article obtained does not require further processing such as phosphating and the article can be subjected to painting directly. Thus, demonstrating improved coating properties of the coating composition on the article.

The present disclosure further relates to a method of coating a substrate with the coating composition described above for obtaining corrosion resistant substrate.

In an embodiment of the present disclosure, the method of coating a substrate with the coating composition for obtaining corrosion resistant substrate comprises- coating the coating composition on to the substrate by techniques including but not limited to spray coating, dip coating, roll coating and wiping method, followed by curing.

In some embodiments of the present disclosure, in the method of coating the substrate with the coating composition, curing is carried out for a duration ranging from about 140 ºC to 250 ºC, including all the values in the range, for instance, 141 ºC, 142 ºC, 143 ºC, 144 ºC and so on and so forth. In an embodiment, the curing is carried out for a duration ranging from about 10 minutes to 15 minutes, including all the values in the range, for instance, 11 minutes, 12 minutes, 13 minutes, 14 minutes and so on and so forth.

In some embodiments of the present disclosure, in the method of coating the substrate, the substate includes but it is not limited to galvanized metal, hot rolled metal and galvalume.

In some embodiments of the present disclosure, the method of coating the substrate can be effected on non-degreased surface and that the coating demonstrates improved surface tolerance and adherent film (5B).
In some embodiments of the present disclosure, obtained coated substrate is corrosion resistance for at least 96 hours, according to salt spray test. In an embodiment, the article is resistant to corrosion for about 96 hours to 120 hours, including all the values in the range, for instance, 97 hours, 98 hours, 99 hours, 100 hours and so on and so forth.

In some embodiments of the present disclosure, the obtained coated substrate does not require further process, such as phosphating and can be directly subjected to painting.

In an embodiment, the obtained coated substrate shows improved salt resistance, surface tolerance and adherent film (5B).

The coating composition and the article of the present disclosure provides for the following advantages.
- The coating composition is economical and environmentally friendly and provides for improved coating on a substrate with improved corrosion resistance, improved surface tolerance and forms adherent film (5B).
- The coating composition is applicable on water drenched and non-degreased surfaces.
- The coating composition provides for transparent surface tolerant coating on non-degreased GI and HR metallic substrate such as hot rolled carbon steel and zero spangled galvanized iron metal.
- The coating composition provides for improved adherence on a substrate upon coating.
- The article coated with the coating composition demonstrates improved corrosion resistance and improved impact resistance.
- The article coated with the coating composition can be directly subjected to painting without any treatment or processing such as phosphating.

It is to be understood that the foregoing description is illustrative not a limitation. While considerable emphasis has been placed herein on particular features of this disclosure, it will be appreciated that various modifications can be made, and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. Those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein. Similarly, additional embodiments and features of the present disclosure will be apparent to one of ordinary skill in art based upon description provided herein.

Descriptions of well-known/conventional methods/steps and techniques are omitted so as to not unnecessarily obscure the embodiments herein. Further, the disclosure herein provides for examples illustrating the above-described embodiments, and in order to illustrate the embodiments of the present disclosure, certain aspects have been employed. The examples used herein for such illustration are intended merely to facilitate an understanding of ways in which the embodiments may be practiced and to further enable those of skill in the art to practice the embodiments. Accordingly, following examples should not be construed as limiting the scope of the embodiments herein.

EXAMPLES

Example 1: Preparing the coating composition
- About 20 wt% of the alkoxy terminated silicone modified polyester is mixed with about 20 wt% of xylene and about 13 wt% of MIBK, followed by stirring at high shear mixing for about 30 minutes to obtain a solution/mixture-A.
- About 2 wt% of the diisobutoxy-bisethylacetatotitante is mixed with about 41 wt% of dichloromethane, followed stirring while purging nitrogen to obtain a solution/mixture-B. Nitrogen purging is carried out only for creating moisture free atmosphere so that sedimentation was prevented. The obtained mixture-B was stirred for at least 5 hours and was subjected to holding time for about one day to stabilize the mixture-B.
- Mixture-A was added to mixture-B while stirring the mixture-B gradually, followed by continuing stirring for about 15 minutes. Further, about 0.5 wt% of the triethyl amine was added to the solution to catalyse the reaction.
- About 2.5 wt% of the zinc sulfonate based corrosion inhibitor was added and about 0.2 wt% of the organo-modified siloxane was added and subjected to high shearing mixing for about 15 minutes to obtain the coating composition.
Below scheme describes the preparation of the coating composition-

The obtained coating composition has the following characteristic features:
- pH of about 6.
- specific gravity of about 1.1 at 27 ºC.
- viscosity of about 75 cps at 27 ºC.
- non-volatile matter of about 25%.

Example 2: Preparing the coating composition
- About 25 wt% of hydroxyl terminated branched silicone modified polyester and about 10 wt% of butanol and 14.5 wt% of MEK were mixed, followed by stirring at high shear mixing for about 30 minutes to obtain a solution/mixture-A.
- About 2 wt% of tetrakis (2-ethylhexyl)titanate was mixed with about 40 wt% of dichloromethane, followed by adding about 0.5 wt% of ethyl acetoacetate and stirred while purging nitrogen to obtain a solution/mixture-B. Nitrogen purging is carried out for creating moisture free atmosphere so that sedimentation was prevented. The obtained mixture-B was stirred for at least 5 hours and was subjected to holding time for about one day to stabilize the mixture-B.
- Mixture-A was added to mixture-B while stirring the mixture-B gradually, followed by continuing stirring for about 15 minutes. Further, about 4.5 wt% of formaldehyde free tris (alkoxycarbonyl amino)triazine crosslinker was added in a ratio of 85 (resin):15 (crosslinker) and about 0.5 wt% of the triethyl amine was added to the solution to catalyse the reaction.
- About 2.5 wt% of the zinc sulfonate based corrosion inhibitor was added and about 0.5 wt% of the polyether modified siloxanes was added and subjected to high shearing mixing for about 15 minutes to obtain the coating composition.

Below scheme describes the preparation of the coating composition-

The obtained coating composition has the following characteristic features:
- pH of about 7.
- specific gravity of about 1.15 at 27 ºC.
- viscosity of about 95 cps at 27 ºC.
- non-volatile matter of about 35%.

Example 3: Preparation of the Article
The coating composition obtained from Example 1 was applied on a metallic substrate by dipping technique, followed by curing the coating on the substrate at a temperature of about 150 ºC for about 10 minutes in hot air oven to obtain the article coated with the coating composition. Dry film thickness of the coating was 10 µm.
The obtained article demonstrates excellent salt resistance of about 96 hours according to salt spray test.
Further, the article was subjected to cross hatch adhesion test, wherein it was noted that the adhesion of the coating composition on the article was 5B.
The obtained article was subjected to direct painting with liquid epoxy painting (thickness 60 to 70 µm) without subjecting the article to processing or treatment such as phosphating. Impact energy of the painted samples were measured using impact tester, it was noted that the painted article was resistant to impact energy of about 11.76 joules and adhesion of about 5B.

Example 4: Preparation of the Article
The coating composition obtained from Example 2 was applied on a metallic substrate by dipping technique, followed by curing the coating on the substrate at a temperature of about 230 ºC for about 10 minutes in hot air oven to obtain the article coated with the coating composition. Dry film thickness of the coating was 15 µm.
The obtained article demonstrates excellent salt resistance of about 120 hours according to salt spray test.
Further, the article was subjected to cross hatch adhesion test, wherein it was noted that the adhesion of the coating composition on the article was 5B.
The obtained article was subjected to direct painting with liquid epoxy painting (thickness 60 to 70 µm) without subjecting the article to processing or treatment such as phosphating. Impact energy of the painted samples were measured using impact tester, it was noted that the painted article was resistant to impact energy of about 13.72 joules and adhesion of about 5B.

Additional embodiments and features of the present disclosure will be apparent to one of ordinary skill in art based on the description provided herein. The embodiments herein provide various features and advantageous details thereof in the description. Descriptions of well-known/conventional methods and techniques are omitted so as to not unnecessarily obscure the embodiments herein.

The foregoing description of the specific embodiments fully reveals the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments in this disclosure have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.

As regards the embodiments characterized in this specification, it is intended that each embodiment be read independently as well as in combination with another embodiment. For example, in case of an embodiment 1 reciting 3 alternatives A, B and C, an embodiment 2 reciting 3 alternatives D, E and F and an embodiment 3 reciting 3 alternatives G, H and I, it is to be understood that the specification unambiguously discloses embodiments corresponding to combinations A, D, G; A, D, H; A, D, I; A, E, G; A, E, H; A, E, I; A, F, G; A, F, H; A, F, I; B, D, G; B, D, H; B, D, I; B, E, G; B, E, H; B, E, I; B, F, G; B, F, H; B, F, I; C, D, G; C, D, H; C, D, I; C, E, G; C, E, H; C, E, I; C, F, G; C, F, H; C, F, I, unless specifically mentioned otherwise.

While considerable emphasis has been placed herein on the particular features of this disclosure, it will be appreciated that various modifications can be made, and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other modifications in the nature of the disclosure or the preferred embodiments will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.