Claims:WE CLAIM:
1) A corrosion resistant hybrid coating formulation comprising organometallic complex and organic resin.

2) The coating formulation as claimed in claim 1, wherein the organometallic complex is a heavy metal based organometallic complex.

3) The coating formulation as claimed in claim 1, wherein the organometallic complex is a reaction product obtained by reacting heavy metal(s) and organic acid(s).

4) The coating formulation as claimed in any of the claims 1 to 3, wherein the heavy metal(s) is selected from the group comprising Vanadium (V), Zirconium (Zr), Titanium (Ti), Manganese (Mn), Hafnium (Hf), Niobium (Nb), Molybdenum (Mo), Tungsten (W), Lanthanum (La) and combinations thereof.

5) The coating formulation as claimed in any of the claims 1 to 4, wherein the heavy metal(s) is V, Zr, Ti, or combinations thereof.

6) The coating formulation as claimed in claim 3, wherein the organic acid(s) is selected from the group comprising lactic acid, citric acid, gluconic acid, oxalic acid and combinations thereof.

7) The coating formulation as claimed in any of the preceding claims, wherein the organometallic complex is a reaction product of V, Zr and lactic acid.

8) The coating formulation as claimed in claim 1, wherein the organic resin is selected from the group comprising acrylic-based resin, polyurethane, methacrylate-based resin, styrene-based resin, polyvinyl dichloride resin, epoxy resin and mixtures thereof.

9) The coating formulation as claimed in claim 8, wherein the acrylic-based resin is polyacrylate.

10) The coating formulation as claimed in claim 1, wherein the formulation comprises one or more additive selected from lubricant, adhesion promoter and stabilizing agent; and wherein the formulation further comprises water.

11) The coating formulation as claimed in claim 1, wherein the formulation comprises lubricant, adhesion promoter and stabilizing agent.

12) The coating formulation as claimed in any of the preceding claims, wherein the lubricant is selected from the group comprising polyethylene wax, polypropylene wax (PP wax), polyvinyl wax, ethylene polyacrylic acid copolymer dispersion, a wax having melting point above 100? and combinations thereof;
the adhesion promoter is a silane selected from the group comprising methacrylsilane, aminosilane, epoxysilane, mercaptosilane, vinylsilane and combinations thereof; and
the stabilizing agent is a non-ionic emulsifier, a cationic emulsifier, pseudo cationic emulsifier or any combination thereof; or wherein the stabilizing agent is selected from the group comprising hexylene glycol, castor-oil based ethoxylates, fatty acid ethoxylates, ethylene oxide (EO) and propylene oxide (PO) block copolymers (EO-PO block copolymers), sorbitan(ol) ester ethoxylates, lanolin, alcohol ethoxylates, polyol esters, amine ethoxylate and combinations thereof.

13) The coating formulation as claimed in any of the preceding claims, wherein the formulation comprises:
i) an organometallic complex of vanadium (V), zirconium (Zr) and lactic acid,
ii) polyacrylate resin,
iii) polyethylene wax,
iv) methacrylsilane,
v) hexylene glycol, and
vi) water.

14) The coating formulation as claimed in any of the preceding claims, wherein the formulation comprises: zirconium divanadate [ZrV2O7], polyacrylate resin, polyethylene wax, methacrylsilane and hexylene glycol.

15) The coating formulation as claimed in any of the preceding claims, wherein the formulation comprises:
i) an organometallic complex of titanium (Ti) and lactic acid,
ii) polyacrylate resin,
iii) polyethylene wax,
iv) methacrylsilane, and
v) water

16) The coating formulation as claimed in any of the preceding claims, wherein the formulation comprises: ammonium titanium lactate or titanium(IV) bis(ammonium lactato)dihydroxide [C6H22N2O8Ti], polyacrylate resin, polyethylene wax, methacrylsilane and water.

17) The coating formulation as claimed in any of the preceding claims, wherein the organometallic complex is in an amount ranging from 1 wt% to 20 wt%, the organic resin is in an amount ranging from 30 wt% to 50 wt%, and the additive is in an amount ranging from 1 wt% to 10 wt%.

18) The coating formulation as claimed in any of the preceding claims, wherein the organometallic complex is in an amount ranging from 1 wt% to 20 wt%, the organic resin is in an amount ranging from 30 wt% to 40 wt%, lubricant is in an amount ranging from 2 wt% to 10 wt%, the adhesion promoter is in an amount ranging from 0.1 wt% to 1 wt%, and the stabilizing agent is in an amount ranging from 0.01 wt% to 0.5 wt%.

19) The coating formulation as claimed in any of the preceding claims, wherein the organometallic complex solution comprises heavy metal in an amount ranging from 5 wt% to 30 wt%.

20) The coating formulation as claimed in any of the preceding claims, wherein the formulation comprises V in an amount ranging from 0.01 wt% to 0.1 wt% and Zr in an amount ranging from 0.1 wt% to 1 wt%
or the formulation comprises Ti in an amount ranging from 0.1 wt% to 1 wt%.

21) The coating formulation as claimed in any of the preceding claims, wherein the formulation comprises organometallic complex of vanadium (V), zirconium (Zr) and lactic acid at 17 wt%, polyacrylate resin at 35 wt%, polyethylene wax at 3 wt%, methacrylsilane at 0.5 wt%, hexylene glycol at 0.5 wt%, and water at 44 wt%.

22) The coating formulation as claimed in any of the preceding claims, wherein the formulation comprises organometallic complex of titanium (Ti) and lactic acid at 20 wt%, polyacrylate resin at 40 wt%, polyethylene wax at 3 wt%, methacrylsilane at 0.5 wt%, and water at 36.5 wt%.

23) The coating formulation as claimed in any of the preceding claims, wherein the formulation is at a pH ranging between 2 to 10.

24) A process of preparing the corrosion resistant hybrid coating formulation as claimed in any of the claims 1 to 23, comprising mixing organometallic complex and organic resin to prepare the coating formulation.

25) The process as claimed in claim 24, wherein the process comprises adding one or more additive.

26) The process as claimed in claim 24, wherein the organic resin is a base polymer; the additive is selected from lubricant, adhesion promoter and stabilizing agent;
and wherein the process comprises:
- reacting metal(s) and organic acid(s) to obtain the organometallic complex; and
- incorporating the organometallic complex along with one or more additive selected from lubricant, adhesion promoter and stabilizing agent, in organic resin matrix, to prepare the coating formulation.

27) The process as claimed in any of the claims 24 to 26, wherein the heavy metal(s) is selected from the group comprising Vanadium (V), Zirconium (Zr), Titanium (Ti), Manganese (Mn), Hafnium (Hf), Niobium (Nb), Molybdenum (Mo), Tungsten (W), Lanthanum (La) and combinations thereof, preferably Vanadium (V), Zirconium (Zr), Titanium (Ti), or combinations thereof;
the organic acid(s) is selected from the group comprising lactic acid, citric acid, gluconic acid, oxalic acid and combinations thereof, preferably lactic acid;
the organic resin is selected from the group comprising acrylic-based resin, polyurethane, methacrylate-based resin, styrene-based resin, polyvinyl dichloride resin, epoxy resin and mixtures thereof, preferably acrylic-based resin; and wherein the acrylic-based resin is polyacrylate;
the lubricant is selected from the group comprising polyethylene wax, polypropylene wax (PP wax), polyvinyl wax, ethylene polyacrylic acid copolymer dispersion, a wax having melting point above 100? and combinations thereof;
the adhesion promoter is a silane selected from the group comprising methacrylsilane, aminosilane, epoxysilane, mercaptosilane, vinylsilane and combinations thereof;
the stabilizing agent is a non-ionic emulsifier, a cationic emulsifier, pseudo cationic emulsifier or combinations thereof; or wherein the stabilizing agent is selected from the group comprising castor-oil based ethoxylates, fatty acid ethoxylates, ethylene oxide (EO) and propylene oxide (PO) block copolymers (EO-PO block copolymers), sorbitan(ol) ester ethoxylates, lanolin, alcohol ethoxylates, polyol esters, amine ethoxylate and combinations thereof;
and wherein the process further comprises adding water.

28) The process as claimed in any of the claims 24 to 27, wherein the organometallic complex is present in an amount ranging from 1 wt% to 20 wt%, the organic resin is present in an amount ranging from 30 wt% to 40 wt%, the lubricant is present in an amount ranging from 2 wt% to 10 wt%, the adhesion promoter is present in an amount ranging from 0.1 wt% to 1 wt%, and the stabilizing agent is present in an amount ranging from 0.01 wt% to 5 wt%.

29) The process as claimed in any of the claims 24 to 28, wherein the prepared formulation comprises organometallic complex of vanadium (V), zirconium (Zr) and lactic acid at 17 wt%, polyacrylate resin at 35 wt%, polyethylene wax at 3 wt%, methacrylsilane at 0.5 wt%, hexylene glycol at 0.5 wt%, and water at 44 wt%;
or the prepared formulation comprises organometallic complex of titanium (Ti) and lactic acid at 20 wt%, polyacrylate resin at 40 wt%, polyethylene wax at 3 wt%, methacrylsilane at 0.5 wt%, and water at 36.5 wt%.

30) The process as claimed in any of the claims 24 to 29, wherein the formulation comprising organometallic complex of vanadium (V), zirconium (Zr) and lactic acid at 17 wt%, polyacrylate resin at 35 wt%, polyethylene wax at 3 wt%, methacrylsilane at 0.5 wt%, hexylene glycol at 0.5 wt%, and water at 44 wt% is prepared by:
- dissolving vanadium salt in lactic acid and incubating for a time period of about 1 hour to 12 hours, followed by adding zirconium salt to obtain the organometallic complex; and
- incorporating the organometallic complex in polyacrylate resin matrix along with polyethylene wax, methacrylsilane, hexylene glycol and water to prepare the coating formulation.

31) The process as claimed in claim 30, wherein the formulation is prepared by:
- dissolving ammonium metavanadate in lactic acid and incubating for a time period of about 12 hours, followed by adding ammonium zirconyl carbonate to obtain the organometallic complex; and
- incorporating the organometallic complex in polyacrylate resin matrix along with polyethylene wax, methacrylsilane, hexylene glycol and water to prepare the coating formulation.

32) The process as claimed in any of the claims 24 to 31, wherein the process is carried out at a pH ranging from about 2 to 10, a temperature ranging from about 20? to 40? and for a time-period ranging from about 2 hours to 24 hours.

33) A method for imparting corrosion resistance to a metal substrate comprising coating the formulation of any of the claims 1 to 23 onto the metal substrate.

34) The method as claimed in claim 33, comprising steps of:
a) providing the metal substrate;
b) coating the formulation onto the substrate; and
c) curing the coated substrate.

35) The method as claimed in claim 33 or claim 34, wherein the metal substrate is a galvanized steel or galvannealed steel.

36) The method as claimed in any of the claims 33 to 35, wherein the coating is dip coating, spray squeeze, roll squeeze or any combination thereof.

37) The method as claimed in claim 34, wherein the curing is performed at a temperature ranging from about 80? to 100?.

38) The method as claimed in any of the claims 33 to 37, comprising steps of:
a) providing a galvanized steel or galvannealed steel;
b) coating the formulation onto said steel by dip coating; and
c) curing the coated steel at a temperature ranging from about 80? to 100?.

39) Use of the corrosion resistant hybrid coating formulation of any of the claims 1 to 23, for imparting corrosion resistance to a metal substrate.

40) A metal substrate coated with the corrosion resistant hybrid coating formulation of any of the claims 1 to 23.

41) The metal substrate as claimed in claim 40, wherein the metal substrate is a galvanized steel or galvannealed steel.
, Description:
TECHNICAL FIELD
The present disclosure is in the field of coating systems. The present disclosure provides a hybrid coating formulation for providing corrosion resistance to metal substrate.

BACKGROUND OF THE DISCLOSURE
Imparting corrosion resistance to metal substrates such as steel is an important area in steel making. Hexavalent chromium based thin organic coatings are usually used in most of the steel plants in the world. Generally, thin organic coatings based on polymers which can crosslink during curing process at elevated temperature are employed. This crosslinking process generates a film with a 3-dimensional networked structure. This network film encapsulates chromium which is an ingredient of the coating chemical. Cr (VI) is the most extensively used ion used in passivation chemical till date. However, the carcinogenic effect of Cr (VI) and environmental regulations have prompted many steel manufacturers to look for chrome free solutions. Accordingly, researchers are in the quest of developing chrome free thin organic coating (TOC) through replacement of hex-chrome with metals such as titanium (Ti), manganese (Mn), vanadium (V) and zirconium (Zr). However, heavy metals such Ti, V, Zr etc. have poor solubility in water contrary to the high solubility of Cr. Further, these heavy metals have a tendency of precipitation/instability when pH is increased. On the other hand, at very low pH, water based polymer resins/systems get precipitated/become instable. Hence, it is very difficult/challenging to incorporate heavy metals into water-based coating systems.

Thus, the existing state of the art coating systems have challenges as discussed above. Accordingly, there is a need for stable and efficient coating systems/formulations for providing corrosion resistance to metal substrates such as steel. The present disclosure tries to address said need.

STATEMENT OF THE DISCLOSURE
The present disclosure relates to a corrosion resistant hybrid coating formulation comprising organometallic complex and organic resin.

The present disclosure further relates to a process of preparing the corrosion resistant hybrid coating formulation as described above, comprising mixing organometallic complex, organic resin, and one or more additive to prepare the coating formulation.

The present disclosure also relates to a method of imparting corrosion resistance to a metal substrate comprising coating the formulation as described onto the metal substrate.

BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURES
Figure 1 illustrates XRD peaks related to different organometallic compounds formed (reaction product of V, Zr and lactic acid).

Figure 2 illustrates crystalline peaks of metal oxide formed in the passive film on curing, as identified by XRD.

Figure 3 illustrates XPS data of the coating film with both organic and inorganic components.

Figure 4 illustrates FTIR peaks for the coated film and coating chemical.

Figure 5 illustrates Raman peaks for the coating chemical and the coated film.

Figure 6 illustrates SEM image of the coated strip (randomly oriented rod-like structures are visible)

Figure 7 illustrates EDX Scan of the coated film.

Figure 8 illustrates microscopic analysis results (Zr is in red color wherein only 2% is localized in crystals and 98% is un-localized and distributed throughout the film).

Figure 9 illustrates image of the coating film obtained by TEM and the corresponding EDS data of TEM.

Figure 10 illustrates: (A) nano crystalline ring for nanocrystals of organometallic component, and (B) some crystalline bright spots indicating crystallinity of the metal oxides encapsulated in the amorphous polymeric film.

Figure 11 depicts potentiodynamic curves for coated and uncoated galvannealed samples in 3.5 wt% NaCl aqueous solution.

Figure 12 depicts equivalent circuit to fit the impedance spectra (Nyquist plot).

Figure 13 illustrates Nyquist spectra for coated and uncoated galvannealed (GA) samples.

Figure 14 illustrates comparative displacement study of the cups coated with oil vs. the present hybrid coating formulation.

Figure 15 illustrates Neutral Salt Spray test (NSST) results by ASTM B117: (A) before forming, and (B) after forming to dome shape.

Figure 16 illustrates XRD peaks related to the characterized Ti based hybrid coating formulation [peaks mainly identified as Silicon Titanium (3/5) and Titanium Zinc (1/2)].

Figure 17 illustrates XPS data of the Ti based hybrid coating film of the present disclosure.

Figures 18 and 20 illustrate micrographs/crystalline structures of the Ti based hybrid coating film obtained by SEM.

Figure 19 illustrates EDS data of the Ti based hybrid coating film of the present disclosure.

Figure 21 illustrates illustrates EDX scan/data of the Ti based hybrid coating film.

Figure 22 illustrates dynamic contact resistance results of Zr-V and Ti based hybrid coating films.

Figure 23 illustrates NSST results (ASTM B117) of Zr-V and Ti based hybrid coating films.

DETAILED DESCRIPTION OF THE DISCLOSURE
With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity. The use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the disclosure to achieve one or more of the desired objects or results. Throughout this specification, the word “comprise”, or variations such as “comprises” or “comprising” or “containing” or “has” or “having” wherever used, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

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 is in relation to coating systems/formulations for metal substrates to impart corrosion resistance.

An objective of the present disclosure is to develop a precipitation stable and efficient coating system for providing corrosion resistance to metal substrates such as steel.

Another objective of the present disclosure is to successfully incorporate heavy metals into water based polymeric resins.

Yet another objective of the present disclosure is to achieve compatibility of corrosion resistant heavy metals in water based polymeric resins.

Still another objective of the present disclosure is to overcome the poor solubility of corrosion resistant heavy metals, preferably V, Zr, Ti, Mn, Hf, Nb, Mo, W and La, when incorporated in water based polymeric resins.

Still another objective of the present disclosure is to address the problem of instability/precipitate formation of heavy metals and water-based polymeric resins at varied pH.

Still another objective of the present disclosure is to develop coating system having applicability at wide pH range.

Still another objective of the present disclosure is to develop coating system having self-lubrication.

The present disclosure is aimed at designing a suitable water-based thin organic coating (TOC) system through incorporation of appreciable amounts of heavy metals such as Vanadium (V), Zirconium (Zr), Titanium (Ti), Manganese (Mn), Hafnium (Hf), Niobium (Nb), Molybdenum (Mo), Tungsten (W) and/or Lanthanum (La) in water-based polymeric resins. For this, first organometallic complexes are formed by reaction(s) of the heavy metal(s) and organic acid(s). The advantage of preparing organometallic complex according to the present disclosure is their stability across a wide range of pH. Otherwise, these heavy metals have a tendency of precipitation when pH is high/increased. On the other hand, at very low pH, water-based polymeric resins such as poly acrylate get precipitated. Hence, this challenge/technical problem is overcome by preparing stable hybrid coating formulations with the incorporation of the heavy metals as organometallic complexes in the polymeric resin matrix.

Accordingly, the present disclosure provides a corrosion resistant hybrid coating formulation comprising organometallic complex and organic resin.

In an embodiment of the present coating formulation, the organometallic complex is a heavy metal based organometallic complex.

In another embodiment of the present coating formulation, the organometallic complex is a reaction product obtained by reacting heavy metal(s) and organic acid(s).

In some embodiments of the present coating formulation, the heavy metal(s) is selected from the group comprising Vanadium (V), Zirconium (Zr), Titanium (Ti), Manganese (Mn), Hafnium (Hf), Niobium (Nb), Molybdenum (Mo), Tungsten (W), Lanthanum (La) and combinations thereof.

In some embodiments of the present coating formulation, the heavy metal(s) is V, Zr, Ti, Mn, Mo or combinations thereof.

In some embodiments of the present coating formulation, the heavy metal is V.

In some embodiments of the present coating formulation, the heavy metal is Zr.

In some embodiments of the present coating formulation, the heavy metal is a combination of V and Zr.

In some embodiments of the present coating formulation, the heavy metal is Ti.

In some embodiments of the present coating formulation, the heavy metal is Mn.

In some embodiments of the present coating formulation, the heavy metal is Mo.

In some embodiments of the present coating formulation, the heavy metal is one or more of Hf, Nb, W and La.

In some embodiments of the present coating formulation, the organic acid(s) is selected from the group comprising lactic acid, citric acid, gluconic acid, oxalic acid and combinations thereof.

In some embodiments of the present coating formulation, the organic acid is lactic acid.

In some embodiments of the present coating formulation, the organic acid is lactic acid and one or more of citric acid, gluconic acid and oxalic acid.

In some embodiments of the present coating formulation, the organometallic complex is a reaction product of V, Zr and lactic acid. In some embodiments of the present coating formulation, the organometallic complex is Zirconium divanadate, Cubic, [ZrV2O7]. Particularly, the reaction product of V, Zr and lactic acid comprises Zirconium divanadate, Cubic, [ZrV2O7], Bis(dimethylammonium) Bis(nitrilotriacetato)zirconate, tetrahydrate [C16H36N4O16Zr1], Ethyl ammonium trivanadate [C2H9NVO3], Tetrakis(methylammonium) tetravanadate, Orthorohmbic [C4H24N4O12V4], Vanadium Zirconium, Cubic [V2Zr], or combinations thereof. Among these reaction products/complexes, the most remarkable/primary peak is shown by Zirconium divanadate and in this cubic structure, both Zr and V atoms co-exist.

In some embodiments of the present coating formulation, the organometallic complex is a reaction product of Ti and lactic acid. In some embodiments of the present coating formulation, the organometallic complex is ammonium titanium lactate or titanium(IV) bis(ammonium lactato)dihydroxide [C6H22N2O8Ti].

In some embodiments of the present coating formulation, the organic resin is selected from the group comprising acrylic-based resin, polyurethane, methacrylate-based resin, styrene-based resin, polyvinyl dichloride resin, epoxy resin and mixtures thereof.

In some embodiments of the present coating formulation, the acrylic-based resin is polyacrylate.

In some embodiments of the present coating formulation, the organic resin is polyacrylate.

In some embodiments of the present coating formulation, the organic resin is polyurethane.

In some embodiments of the present coating formulation, the organic resin is epoxy resin.

In some embodiments of the present coating formulation, the formulation comprises one or more additive selected from lubricant, adhesion promoter and stabilizing agent.

In some embodiments of the present coating formulation, the formulation comprises lubricant.

In some embodiments of the present coating formulation, the formulation comprises adhesion promoter.

In some embodiments of the present coating formulation, the formulation comprises stabilizing agent.

In some embodiments of the present coating formulation, the formulation comprises lubricant, adhesion promoter and stabilizing agent.

In some embodiments of the present coating formulation, the lubricant is selected from the group comprising polyethylene wax, polypropylene wax (PP wax), polyvinyl wax, ethylene polyacrylic acid copolymer dispersion, a wax having melting point above 100? and combinations thereof.

In some embodiments of the present coating formulation, the lubricant is polyethylene wax.

In some embodiments of the present coating formulation, the adhesion promoter is a silane.

In some embodiments of the present coating formulation, the adhesion promoter is a silane selected from the group comprising methacrylsilane, aminosilane, epoxysilane, mercaptosilane, vinylsilane and combinations thereof.

In some embodiments of the present coating formulation, the adhesion promoter is methacrylsilane.

In some embodiments of the present coating formulation, the stabilizing agent is a non-ionic emulsifier, a cationic emulsifier, pseudo cationic emulsifier or combinations thereof.

In some embodiments of the present coating formulation, the stabilizing agent is selected from the group comprising hexylene glycol, castor-oil based ethoxylates, fatty acid ethoxylates, ethylene oxide (EO) and propylene oxide (PO) block copolymers (EO-PO block copolymers), sorbitan(ol) ester ethoxylates, lanolin, alcohol ethoxylates, polyol esters, glycols, amine ethoxylate and combinations thereof.

In some embodiments of the present coating formulation, the stabilizing agent is hexylene glycol.

In some embodiments of the present coating formulation, the total wt% of the coating formulation is made up to 100% by adding additional additives such as surfactants, wetting agents, curing agents and/or defoamer. In some embodiments of the present coating formulation, the total volume of the coating formulation is made up to 100 wt% by adding water. In some embodiments, the water is demineralized (DM) water. In some embodiments of the present coating formulation, the total volume or wt% of the coating formulation is made up to 100% by adding DM water.
In some embodiments of the disclosure, the coating formulation comprises:
i) an organometallic complex of vanadium (V), zirconium (Zr) and lactic acid,
ii) polyacrylate resin,
iii) polyethylene wax,
iv) methacrylsilane,
v) hexylene glycol and
vi) water

In some embodiments of the disclosure, the coating formulation comprises: Zirconium divanadate, Cubic, [ZrV2O7], polyacrylate resin, polyethylene wax, methacrylsilane and hexylene glycol.

In some embodiments of the disclosure, the coating formulation comprises: Zirconium divanadate, Cubic, [ZrV2O7], polyacrylate resin, polyethylene wax, methacrylsilane, hexylene glycol and DM water.

In some embodiments of the disclosure, the coating formulation comprises:
i) an organometallic complex of titanium (Ti) and lactic acid,
ii) polyacrylate resin,
iii) polyethylene wax,
iv) methacrylsilane,
v) hexylene glycol, and
vi) water

In some embodiments of the disclosure, the coating formulation comprises: ammonium titanium lactate or titanium(IV) bis(ammonium lactato)dihydroxide, polyacrylate resin, polyethylene wax, methacrylsilane and hexylene glycol.

In some embodiments of the disclosure, the coating formulation comprises: ammonium titanium lactate or titanium(IV) bis(ammonium lactato)dihydroxide, polyacrylate resin, polyethylene wax, methacrylsilane, hexylene glycol and DM water.

In some embodiments of the present coating formulation, the organometallic complex is in an amount ranging from 1 wt% to 20 wt%, including all values or ranges therefrom.

In some embodiments of the present coating formulation, the organic resin is in an amount ranging from 20 wt% to 50 wt%, including all values or ranges therefrom.

In some embodiments of the present coating formulation, the additive selected from lubricant, adhesion promoter, stabilizing agent and combinations thereof is in an amount ranging from 1 wt% to 10 wt%, including all values or ranges therefrom. In some embodiments of the present coating formulation, the additive selected from lubricant, adhesion promoter, stabilizing agent and combinations thereof is in an amount ranging from 2 wt% to 10 wt%, including all values or ranges therefrom.

In some embodiments of the present coating formulation, the lubricant is in an amount ranging from 2 wt% to 10 wt%, including all values or ranges therefrom.

In some embodiments of the present coating formulation, the adhesion promoter is in an amount ranging from 0.1 wt% to 2 wt%, including all values or ranges therefrom. In some embodiments of the present coating formulation, the adhesion promoter is in an amount ranging from 0.1 wt% to 1 wt%, including all values or ranges therefrom.

In some embodiments of the present coating formulation, the stabilizing agent is in an amount ranging from 0 wt% to 2 wt%, including all values or ranges therefrom. In some embodiments of the present coating formulation, the stabilizing agent is in an amount ranging from 0.01 wt% to 0.5 wt%, including all values or ranges therefrom. In some embodiments of the present coating formulation, the stabilizing agent is in an amount ranging from 0 wt% to 2 wt%, including all values or ranges therefrom. In some embodiments of the present coating formulation, the stabilizing agent is in an amount ranging from 0.5 wt% to 2 wt%, including all values or ranges therefrom.

In some embodiments of the present coating formulation, the above wt% of organometallic complex, organic resin and additive is with respect to the total wt% of the coating formulation.

As discussed above, in some embodiments of the present coating formulation, the total wt% of the coating formulation is made up to 100% by adding additional additives or components such as surfactants, wetting agents, curing agents and defoamer.

In some embodiments, water is employed to make up the final volume of the present coating formulation to 100 wt%. In some embodiments, the water is demineralized (DM) water. In some embodiments, the total wt% of the coating formulation is made up to 100% by adding DM water.

In some embodiments of the present coating formulation, the organometallic complex solution comprises heavy metal in an amount ranging from 3 wt% to 7 wt% and organic acid in an amount ranging from 30 wt% to 40 wt%. Said wt% is with respect to the total wt% of the organometallic complex solution.

In some embodiments of the present coating formulation, the formulation comprises V in an amount ranging from 0.01 % to 0.1 % and Zr in an amount ranging from 0.1 % to 1 % with respect to the total weight of the coating formulation.

In some embodiments of the present coating formulation, the formulation comprises organometallic complex (reaction product) of vanadium (V) source, zirconium (Zr) source and lactic acid at 17 wt%, polyacrylate resin at 35 wt%, polyethylene wax at 5 wt%, methacrylsilane at 0.5 wt%, and hexylene glycol at 0.05 wt%.

In some embodiments of the present coating formulation, the formulation comprises organometallic complex of vanadium (V), zirconium (Zr) and lactic acid at 17 wt%, polyacrylate resin at 35 wt%, polyethylene wax at 3 wt%, methacrylsilane at 0.5 wt%, hexylene glycol at 0.5 wt%, and water at 44 wt%.

In some embodiments of the present coating formulation, the formulation comprises organometallic complex of vanadium (V), zirconium (Zr) and lactic acid at 10 wt%, polyacrylate resin at 40 wt%, polyethylene wax at 5 wt%, methacrylsilane at 0.5 wt% and water at 44.5 wt%.

In some embodiments of the present coating formulation, the formulation comprises organometallic complex (reaction product) of titanium (Ti) source and lactic acid at 20 wt%, polyacrylate resin at 40 wt%, polyethylene wax at 5 wt%, methacrylsilane at 0.5 wt%.

In some embodiments of the present coating formulation, the formulation comprises organometallic complex of titanium (Ti) and lactic acid at 20 wt%, polyacrylate resin at 40 wt%, polyethylene wax at 3 wt%, methacrylsilane at 0.5 wt%, and water at 36.5 wt%.

In some embodiments of the present coating formulation, the formulation comprises organometallic complex of titanium (Ti) and lactic acid at 10 wt%, polyacrylate resin at 40 wt%, polyethylene wax at 5 wt%, methacrylsilane at 0.5 wt% and water at 44.5 wt%.

In some embodiments of the present coating formulation, the formulation is at a pH ranging between 2 to 10, including all values and ranges therefrom.

In some embodiments of the present coating formulation, the formulation is at a pH of 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5 or 10.

The present disclosure further relates to a process of preparing the corrosion resistant hybrid coating formulation as described above, comprising mixing the organometallic complex, the organic resin, and one or more additive to prepare the coating formulation.

In some embodiments of the process, the additive is selected from lubricant, adhesion promoter and stabilizing agent.

In some embodiments of the process, the additive is lubricant, adhesion promoter and stabilizing agent.

In some embodiments of the process, the organic resin is a base polymer.

In some embodiments, the process of preparing the corrosion resistant hybrid coating formulation comprises:
- reacting metal(s) and organic acid(s) to obtain the organometallic complex, and
- incorporating the organometallic complex along with one or more additive selected from lubricant, adhesion promoter and stabilizing agent, in organic resin matrix, to prepare the coating formulation.

In some embodiments, the process of preparing the corrosion resistant hybrid coating formulation comprises:
- reacting metal(s) and organic acid(s) to obtain the organometallic complex, and
- incorporating the organometallic complex along with lubricant, adhesion promoter, stabilizing agent and water, in organic resin matrix, to prepare the coating formulation.

In some embodiments of the above described process, the heavy metal(s) is selected from the group comprising Vanadium (V), Zirconium (Zr), Titanium (Ti), Manganese (Mn), Hafnium (Hf), Niobium (Nb), Molybdenum (Mo), Tungsten (W), Lanthanum (La) and combinations thereof.

In some embodiments of the above described process, the heavy metal(s) is Vanadium (V), Zirconium (Zr), Titanium (Ti), or a combination thereof.

In some embodiments of the above described process, the organic acid(s) is selected from the group comprising lactic acid, citric acid, gluconic acid, oxalic acid and combinations thereof.

In some embodiments of the above described process, the organic acid is lactic acid.

In some embodiments of the above described process, the organic resin is selected from the group comprising acrylic-based resin, polyurethane, methacrylate-based resin, styrene-based resin, polyvinyl dichloride resin, epoxy resin and mixtures thereof.

In some embodiments of the above described process, the organic resin is acrylic-based resin.

In some embodiments of the above described process, the acrylic-based resin is polyacrylate.

In some embodiments of the above described process, the acrylic-based resin is epoxy resin.

In some embodiments of the above described process, the lubricant is selected from the group comprising polyethylene wax, polypropylene wax (PP wax), polyvinyl wax, ethylene polyacrylic acid copolymer dispersion, a wax having melting point above 100? and combinations thereof.

In some embodiments of the above described process, the lubricant is polyethylene wax.

In some embodiments of the above described process, the adhesion promoter is a silane selected from the group comprising methacrylsilane, aminosilane, epoxysilane, mercaptosilane, vinylsilane and combinations thereof.

In some embodiments of the above described process, the adhesion promoter is methacrylsilane.

In some embodiments of the above described process, the stabilizing agent is a non-ionic emulsifier, a cationic emulsifier, pseudo cationic emulsifier or combinations thereof.

In some embodiments of the above described process, the stabilizing agent is selected from the group comprising hexylene glycol, castor-oil based ethoxylates, fatty acid ethoxylates, ethylene oxide (EO) and propylene oxide (PO) block copolymers (EO-PO block copolymers), sorbitan(ol) ester ethoxylates, lanolin, alcohol ethoxylates, polyol esters, glycols, amine ethoxylate and combinations thereof.

In some embodiments of the above described process, the stabilizing agent is hexylene glycol.

In some embodiments of the above described process, the organometallic complex is present in an amount ranging from 1 wt% to 20 wt%, organic resin is present in an amount ranging from 20 wt% to 50 wt%, lubricant is present in an amount ranging from 2 wt% to 10 wt%, adhesion promoter is present in an amount ranging from 0.0 wt% to 0.5 wt%, and stabilizing agent is present in an amount ranging from 0.0 wt% to 0.5 wt%.

In some embodiments of the above described process, the organometallic complex is present in an amount ranging from 1 wt% to 20 wt%, organic resin is present in an amount ranging from 20 wt% to 50 wt%, lubricant is present in an amount ranging from 2 wt% to 10 wt%, adhesion promoter is present in an amount ranging from 0.0 wt% to 0.5 wt%, stabilizing agent is present in an amount ranging from 0.0 wt% to 0.5 wt% and the remaining is water to make up the formulation up to 100 wt%.

In some embodiments of the above described process, the organometallic complex is a reaction product of vanadium (V) source, zirconium (Zr) source and lactic acid.

In some embodiments of the above described process, the organometallic complex is a reaction product of titanium (Ti) source and lactic acid.

In some embodiments of the above described process, the organometallic complex of Zr and V is Zirconium divanadate, Cubic, [ZrV2O7]. Particularly, the reaction product of V, Zr and lactic acid comprises Zirconium divanadate, Cubic, [ZrV2O7], Bis(dimethylammonium) Bis(nitrilotriacetato)zirconate, tetrahydrate [C16H36N4O16Zr1], Ethyl ammonium trivanadate [C2H9NVO3], Tetrakis(methylammonium) tetravanadate, Orthorohmbic [C4H24N4O12V4], Vanadium Zirconium, Cubic [V2Zr], or combinations thereof. Among these reaction products/complexes, the most remarkable/primary peak is shown by Zirconium divanadate and in this cubic structure, both Zr and V atoms co-exist.

In some embodiments of the above described process, the organometallic complex is ammonium titanium lactate or titanium(IV) bis(ammonium lactato)dihydroxide.

In some embodiments of the above described process, the prepared formulation comprises organometallic complex (reaction product) of vanadium (V) source, zirconium (Zr) source and lactic acid at 17 wt%, polyacrylate resin at 35 wt%, polyethylene wax at 5 wt%, methacrylsilane at 0.3 wt%, and hexylene glycol at 0.05 wt%.

In some embodiments of the above described process, the prepared formulation comprises organometallic complex of vanadium (V), zirconium (Zr) and lactic acid at 17 wt%, polyacrylate resin at 35 wt%, polyethylene wax at 3 wt%, methacrylsilane at 0.5 wt%, hexylene glycol at 0.5 wt%, and water at 44 wt%.

In some embodiments of the above described process, the prepared formulation comprises organometallic complex (reaction product) of titanium (Ti) and lactic acid at 20 wt%, polyacrylate resin at 40 wt%, polyethylene wax at 5 wt%, methacrylsilane at 0.5 wt%.

In some embodiments of the above described process, the prepared formulation comprises organometallic complex of titanium (Ti) and lactic acid at 20 wt%, polyacrylate resin at 40 wt%, polyethylene wax at 3 wt%, methacrylsilane at 0.5 wt%, and water at 36.5 wt%.

In some embodiments of the above described process, the formulation comprising organometallic complex of vanadium (V), zirconium (Zr) and lactic acid at 17 wt%, polyacrylate resin at 35 wt%, polyethylene wax at 3 wt%, methacrylsilane at 0.5 wt%, hexylene glycol at 0.5 wt%, and water at 44 wt% is prepared by:
- dissolving vanadium salt in lactic acid and incubating for a time period of about 1 hour to 12 hours, followed by adding zirconium salt to obtain the organometallic complex; and
- incorporating the organometallic complex in polyacrylate resin matrix along with polyethylene wax, methacrylsilane, hexylene glycol and water to prepare the coating formulation.

In some embodiments of the above described process, the formulation is prepared by:
- dissolving vanadium salt in lactic acid and incubating for a time period of about 0.5 hours to 1 hours, followed by adding zirconium salt to obtain the organometallic complex; and
- incorporating the organometallic complex in polyacrylate resin matrix along with polyethylene wax, methacrylsilane and water to prepare the coating formulation.

In some embodiments of the above described process, the formulation is prepared by:
- dissolving ammonium metavanadate in lactic acid and incubating for a time period of about 12 hours to 24 hours, followed by adding ammonium zirconyl carbonate to obtain the organometallic complex; and
- incorporating the organometallic complex in polyacrylate resin matrix along with polyethylene wax, methacrylsilane and hexylene glycol to prepare the coating formulation.

In some embodiments, the above described process for preparing the coating formulation is carried out at a pH ranging from about 2 to 10, a temperature ranging from about 20? to 40? and for a time-period ranging from about 0.5 hours to 24 hours.

The present disclosure also relates to a method of imparting corrosion resistance to a metal substrate comprising coating the formulation as described above onto the metal substrate.

In some embodiments, the method of imparting corrosion resistance to a metal substrate comprises steps of:
a) providing the metal substrate;
b) coating the formulation onto the substrate; and
c) curing the coated substrate.

In some embodiments, the metal substrate is a galvanized steel or galvannealed steel.

In some embodiments, the coating is dip coating, spray squeeze, roll coating, or any combination thereof.

In some embodiments, the coating is dip coating.

In some embodiments, the curing is performed at a temperature ranging from about 80? to 85?.

In some embodiments, the method of imparting corrosion resistance to a metal substrate comprises steps of:
a) providing a galvanized steel or galvannealed steel;
b) coating the formulation as described above onto the steel by dip coating; and
c) curing the coated steel at a temperature ranging from about 80? to 85?.

The present disclosure also relates to the use of the corrosion resistant hybrid coating formulation as described above, for imparting corrosion resistance to a metal substrate.

In some embodiments of the use, the metal substrate is galvanized steel or galvannealed steel.

The present disclosure further provides a metal substrate coated with the corrosion resistant hybrid coating formulation as described above. In some embodiments, the metal substrate is a galvanized steel or galvannealed steel.

Thus, the present disclosure provides corrosion resistant hybrid coating formulations and processes/methods thereof. Particularly, to overcome the technical problems such as poor solubility/compatibility of the corrosion resistant heavy metals in organic resins, organometallic complexes are produced. The organometallic solution is stably incorporated in the matrix of organic/polymeric resin moiety. The resultant product can be coated and cured on metal substrates such as galvanized or galvannealed (GA) steel substrate. The change in chemical nature of the coated film is studied by methods such as FTIR and Raman Spectroscopy as further described in the Examples below. When the coating film is cured in presence of Zn, they form many multi-metal/multi-metal oxides on the coating film. In addition to that, some metal atoms form bonds with the functional groups of the polymer film. These metals are distributed uniformly though the whole metal surface. Because of the presence of the metals in two different ways (oxides and salt of the organic functional group) it gives excellent corrosion resistance. The corrosion study was done by both NSST and electrochemical tests as described in the Examples below. It was found that corrosion resistance properties are retained even after forming operation which indicates that the film is adherent and is capable of imparting lubrication even in the absence of lubricating oil during forming operation. In other words, the present hybrid organic coating formulation forms a self-lubricating film which can reduce the friction during forming operation and can replace lubricating oil.

In an embodiment, the foregoing descriptive matter is illustrative of the disclosure and not a limitation. Although preferred embodiments have been depicted and described in detail herein, it will be apparent to those skilled in the relevant art that various modifications, additions, substitutions, and the like can be made without departing from the spirit of the invention and these are therefore considered to be within the scope of the invention as defined in the claims which follow. Further, to the extent not already indicated, it will be understood by those of ordinary skill in the art that any one of the various embodiments herein described and illustrated can be further modified to incorporate features shown in any of the other embodiments disclosed herein. In other words, 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.

Further, it should be understood that this invention is not limited to the particular methodology, protocols, and reagents, etc., described herein and as such may vary. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the present invention, which is defined solely by the claims.

As regards all the embodiments/examples characterized in this specification, in particular in the claims, it is intended that each embodiment mentioned in a dependent claim is combined with each embodiment of each claim (independent or dependent) said dependent claim depends from. As an example, in case of an independent claim 1 reciting 3 alternatives A, B and C, a dependent claim 2 reciting 3 alternatives D, E and F and a claim 3 depending from claims 1 and 2 and 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; and C, F, I, unless specifically mentioned otherwise.

Similarly, and also in those cases where independent and/or dependent claims do not recite alternatives, it is understood that if dependent claims refer back to a plurality of preceding claims or plurality of embodiments, any combination of subject-matter covered thereby is considered to be explicitly disclosed. For example, in case of an independent claim 1, a dependent claim 2 referring back to claim 1, and a dependent claim 3 referring back to both claims 2 and 1, it follows that the combination of the subject-matter of claims 3 and 1 is clearly and unambiguously disclosed as is the combination of the subject-matter of claims 3, 2 and 1. In case a further dependent claim 4 is present which refers to anyone of claims 1 to 3, it follows that the combination of the subject-matter of claims 4 and 1, of claims 4, 2 and 1, of claims 4, 3 and 1, as well as of claims 4, 3, 2 and 1 is clearly and unambiguously disclosed.

The above considerations apply mutatis mutandis to all claims and embodiments of the present specification. To give a few examples, the combination of claims 4, 6 and 1 is clearly and unambiguously envisaged in view of the claim structure/claimed subject-matter. The same applies for the combinations of claims 12, 10, 4 and 6, and, to give a few further examples which are not limiting, the combination of claims 13, 15, 17 and 18 and the combination of claims 23, 24 and 25.

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 below 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 herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the following examples should not be construed as limiting the scope of the embodiments herein.

EXAMPLES

EXAMPLE 1: Synthesis of V and Zr based thin organic coating (TOC) formulation
The heavy metals vanadium (V) and zirconium (Zr) were chosen for preparing the coating formulation. Initially, organometallic complex crystals based on V and Zr was prepared. To make the crystals, the solution V and Zr complex was prepared in the following way:

About 2 gm of ammonium metavanadate (source of V metal) was dissolved in about 35 gm of lactic acid (organic acid). The solution formed was dark red in colour. The solution was kept overnight, and the solution became blue i.e. the formation of vanadium lactate was completed. The colour of the solution from red to blue further reflects the change in the oxidation state of vanadium from +5 to +3. Next, about 45g of ammonium zirconyl carbonate solution (source of Zr metal) was added which turns the solution instantaneously to green. This indicates the change in oxidation state of vanadium from +5 to +4. This is also an indication of complexometric bond formation between vanadium lactate and zirconium carbonate. The addition of ammonium zirconyl carbonate continued till the pH 4.5. The resultant organometallic complex solution contained 0.42% of V and 3.54% of Zr. Thereafter, the solution was boiled to reduce the volume to 50%. The solution was further kept for about 4 days undisturbed. Some crystal formation was observed. These crystals were light blue in colour. The crystals were recrystallized in 50% ethanol. These crystals were analysed in X-Ray Diffraction (XRD).

The polyacrylate resin (base polymer) emulsion was taken and stabilized with either non-ionic or cationic emulsifier. Hexylene glycol can also be used as an alternate stabilizing agent. The polyacrylate from Alberdingk Boley (AC 2486 VP) was taken and was found to be absolutely stable when incorporated with the above prepared organometallic complex. Polyethylene wax (lubricant) and acrylic silane (adhesion promoter) were also added to the coating system. The resultant final hybrid coating formulation contained 0.074% of V and 0.6% Zr. The hybrid coating formulation comprises 17 wt% of organometallic complex, 35 wt% of polyacrylate resin, 5 wt% of polyethylene wax, and 0.5 wt% of acrylic silane/methacrylsilane.

The prepared coating formulation was applied to galvanized metal substrate by dip coating. The coated sheet was cured at peak metal temperature at about 80-85oC. A transparent and uniform coating was achieved. The coating weight was found to be 1-1.2 g/m2/side.

EXAMPLE 2: Characterization and Activity Study of the coating formulation prepared in Example 1

X-ray Diffraction Study
The organometallic compound which was recrystallized by 50% ethanol was analysed by XRD. In XRD, with the help of absolute scan, several sharp peaks were obtained. These peaks were identified as Bis(dimethylammonium) Bis(nitrilotriacetato)zirconate, tetrahydrate. This compound has the chemical structure of C16H36N4O16Zr1. This is a monoclinic crystal lattice. Ethyl ammonium trivanadate, Tetrakis(methylammonium) Tetravanadate, Orthorohmbic C4H24N4O12V4, Zirconium Divanadate, Cubic, ZrV2O7, Vanadium Zirconium, Cubic V2Zr with similar remarkable peaks were identified. Among them, the most remarkable peak was zirconium divanadate (ZrV2O7), because in this cubic structure both Zr and V atoms were co-existing (Figure 1).

When the coated sheet was analysed by absolute scan in XRD, crystalline peaks were found there as well. Those peaks were Vanadium oxide, Zirconium oxide, Zirconium silicide, Zirconium zinc and Vanadium zirconium (Figure 2). Thus, it is confirmed that the organometallic compounds are converted into metal oxides or intermetallic compounds in the passive film during the curing process.

X-ray Photoelectron Spectroscopy (XPS)
XPS spectra indicated a sharp peak for ZrO2 having binding energy in 182 eV (Figure 3). In addition, many organic peaks were also identified. These peaks are generated based on the organic film of the hybrid coating. C1s signals show bonds as C-O, O-C=O, C-O-C, C-O, C-O-Si peaks. From O1s signals, O-C=O, C=O, C-O-C/OH peaks were also identified. The details of the binding energies and component fraction are provided in Table 1.

Table 1: Description of XPS data
Signal Bonds Energy of bonds/eV Component %
C1s C-O 287.6 8.7
O-C=O 288.6 5.1
C-O-C 286.5 9.1
C-O/C-O-Si 285.3 71.8
C-Si 284.2 5.0
O1s O–C=O 531.65 80.4
C=O 531.65
C–O–C/OH 533.7 19.6
Zn ZnO 1021.8 100
Zr ZrO2 187.2 100%

Fourier-Transform Infrared Spectroscopy (FTIR)
FTIR spectra of the formulation showed significant peaks as indicated in Figure 4 and Table 2 below. The carboxylate peaks (1727 cm-1) are present in the polyacrylate moiety which is also seen to be present in the coated film. This indicates that despite the crosslinking reaction, free carboxylic groups are available. Moreover, in the coated film, carboxylic acid - metal salt peak (at 1599 cm-1) is also observed which is found to be absent in the formulation. Strong peak corresponding to Si-O-Si- / Si-O-C- group is found at 1133 cm-1 in the formulation. However, broadening of this peak was observed at 1091cm-1 in the coated system indicating the formation of cross-linked silane network. A peak at 1627 cm-1 indicating the presence of conjugated keto group was observed in the formulation which was found to be absent in the coating indicating cross-linking reaction during curing. The comparative positions of the different peaks are illustrated in Table 2.

Table 2: Peak details of FTIR Spectra
Peak in cm-1 Peak in product Peak in coating Remarks
1727 sharp peak Carboxylic group Carboxylic group Free carboxylic group is present in both product and film
1627 Conjugated keto group Absent in coating Cross-linking reaction in this site
1599 broad peak Absent in product Carboxylic metal salt Formation of bond between -COOH and Zr/V or metal substrate.
1127 sharp peak Si-O-Si/ Si-O-C - Silane peak
1091 - Silico-metal oxide Cross-linking reaction of silane

Raman Spectroscopy
Similar analysis was carried out with Raman spectroscopy to corroborate the findings from FTIR analysis. The spectra of the peaks obtained for both the formulation and the film is summarized in Table 3 below.

In the formulation, less intense peaks at 201 cm-1 and 358 cm-1 are observed which are representative of ? (M-O) bonds. These peaks get further intensified in the coating film which indicate metal-oxide bond formation in the film. The peak at 550 cm-1 corresponding to ? (Si-O-Si) is observed in the spectra of the film but it is absent in the formulation. This is because new bonds are formed due to the crosslinking reaction of methacrylate silane present in the product. Peaks in the spectra of the formulation at 808 cm-1 and 837 cm-1 are associated with ? (C-O-C). In addition to these two peaks, another peak at 869 cm-1 was also observed in the film. These peaks get intensified in the film which can explain the formation of new bonds in the crosslinking reaction. A strong peak at 1058 cm-1 associated with ? (C-O-C) asymmetric in the spectra of the formulation generated many new peaks at 1056, 1086 and 1124 cm-1. This also concludes the formation of new cross-liked bonds in the polyacrylate film. A strong peak at 1450 cm-1 is associated with d (CH3) asymmetric present in both the formulation and film. Peaks at 1724 cm-1 associated with ? (C=O) is present in both the formulation and film (Figure 5).

Table 3: Peak details for Raman Spectra of both product and coating system
Peak Product Coating film Remarks
? (Si-O-Si) 550
? (X Metal-O) 291,358 208, 291 Peaks are intensified in film
? (C-O-C) 808, 837 808, 837, 869 Several new peaks are generated in film
? (C-O-C)asy 1058 1056, 1086, 1124 New peaks are formed in film
d (CH3)asy 1450 1450 No change in peak position
? (C=O) 1724 1723 Free carboxylic group are available

Microscopy
Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM) was used to understand the morphology of the coating. From the Energy-dispersive X-ray spectroscopy (EDX), line scanning and mapping, the distribution of metals/metal compounds in the hybrid coating film were investigated. By TEM image, the crystallinity was also investigated.

Particularly, Scanning Electron Microscope (SEM) was used to understand the morphology of the coating system. Crystalline structure was observed in the micrographs for the coated system (Figure 6). Energy Dispersive Spectroscopy (EDX) analysis shows the presence of C, O, Zn, Zr, V across the test area (Table 4). Surface mapping indicates that V and Zr are uniformly distributed throughout the matrix. This is because, upon curing, the organometallic compound forms bond and gets crosslinked with the functional group (mostly carboxylic group and -OH group) present in the polymeric resin moiety. The presence of carboxylic salt was also indicated by FTIR spectra. The area where crystalline structures are found are rich in O and also metals. This confirms that the crystals which are formed in the coating are compounds of Zr, V and O. XRD analysis indicates the presence of Zirconium divanadate, Vanadium zirconium, Vanadium oxide, Zirconium oxide etc. X-ray photoelectron spectroscopy (XPS) analysis also indicates strong peak of Zirconium dioxide. From mapping, it is indicated that only 2% of Zirconium is concentrated in the crystals of oxides. Other 98% is distributed through the film matrix. When line mapping is done in the crystal, 72 % is O, 26% is Zr and 2% is V (Figure 7).
Table 4: EDX data of different elements in the coated film
Element Weight % Atomic %
C K 29.70 43.22
O K 45.85 50.09
SiK 1.08 0.67
ZrL 4.27 0.82
V K 0.48 0.17
FeK 1.17 0.37
ZnK 17.45 4.67

Further, TEM analysis shows similar results as that of SEM. The coating film consists of amorphous organic film where crystals of the metal are encapsulated. The EDX results shows the presence of C, O, Si, Zr and V peaks (Figure 9). The crystallinity is concentrated on black particle which are reach in metals. Some unidirectional crystal dots were observed in the black spots and rest of the film showed amorphous structure (Figure 10).

Electrochemical Characterisation
Electrochemical tests were carried out by a Gamry 1010E potentiostat. Coated galvannealed samples were immersed in a 3-electrode test cell along with a platinum counter electrode and a standard calomel reference electrode. Exposed area of each sample in the solution was kept as 1.0 cm2. Samples were allowed to stabilise at their open circuit potential (OCP) for 1800 secs before further electrochemical tests were carried out. The corrosion rate of coated substrates was measured by potentiodynamic polarisation in 3.5% aqueous solution of NaCl with a scan rate of 0.05 mV/s in accordance with ASTM G59 - 97(2014). All electrochemical impedance spectroscopy (EIS) spectra were recorded at OCP in a frequency scan range from 0.1 Hz to 100 000 Hz, with ac excitation amplitude of 0.025 V in 3.5% aqueous solution of NaCl.

Potentiodynamic polarization curves give a comparative analysis between the effect of the chrome-free thin organic coating on the corrosion performance of the galvannealed steel. Figure 11 shows the potentiodynamic polarization curve of the coated system against that of uncoated steel. It is evident from the curves that the corrosion current density is considerably lower in case of the coated system as compared to the uncoated galvannealed sample. Moreover, the decrease in the corrosion potential, albeit, very less, is indicative of the fact that the coated system is nobler as compared to that of the uncoated system (Table 5).

Table 5: Corrosion study of coated and uncoated galvannealed (GA) samples
Sample Ecorr, mV Icorr, µA/cm2 Corrosion Rate, mpy
Uncoated GA -882 6.01 3.551
Coated GA -890 0.86 0.51

Electrochemical impedance study was done to understand the basic mechanism in terms of the protective behavior. It can be understood from the Nyquist plot (Figure 13) and Table 6 that the impedance to corrosion is in correlation with the findings in that of the potentiodynamic polarization studies. The spectra was fitted against the equivalent circuit shown in Figure 12. The fitted values give an indication of the corrosion behavior of coated and uncoated substrate in terms of coating film resistance (Rc), charge transfer due to the formation of oxide layer (Rct), double layer capacitance (Cdl) and film capacitance (Cc) which in turn gives an idea regarding the barrier resistance offered by the film. The data shows a clear trend that the film resistance and the charge transfer resistance across the coating film is greater in case of coated sample thus indicating that sufficient barrier protection is offered by the cross-linked film.

Table 6: Electrochemical impedance parameters for uncoated and coated galvannealed samples
Sample Rsol, O Rct, O Cdl, F Rc, O Cc, F
Uncoated GA 20.8 687.3 3.42E-05 6.25E+03 1.93E-03
Coated GA 20.89 1.25E+03 6.19E-05 1.26E+04 3.72E-05

Forming test
GA samples (210*297*0.78mm) were cleaned with silicate free alkaline degreasing solution and subsequently coated with hybrid coating formulation. Standard 100 mm diameter blanks were machined out from coated as well as uncoated GA sheets for cupping tests. Formability tests were conducted on a 60T servo-hydraulic forming press by varying the blank holding force and the resultant punch force and displacement was measured. Cupping test was performed in three coated sheets, namely: 1) GA sheet, coated with oil which is normally used in automotive industries during the forming operation; 2) GA sheet coated with hybrid coating formulation prepared in Example 1; and 3) GA sheet coated with hybrid coating formulation prepared in Example 1 as well as oil. The punch force was gradually increased by 10 kN till the fracture appeared. The different areas of the cup was named as base, bent, side and neck. These portions were thoroughly studied by SEM and analysed by EDS to examine any change in the morphology of the coating during drawing operation. Corrosion tests were also performed by exposing the material before and after forming operation in Neutral Salt Spray test (NSST) by ASTM B117.

Another forming test was also performed by drawing the A4 size coated sheet into the shape of a Dome. The dome was cut into two halves. First half of the dome was analysed by SEM and EDX to check if there is any morphology change after the forming operation and half of the sample was exposed to NSST.

Results of Forming test
When cupping test was carried out, it was observed that with the same blank holding force, there is a significant reduction of punch load in GA sheet coated with the hybrid coating formulation when compared to the oil coated GA. The comparative data of punch load with the variation of blank holding force (BHF) is shown in Figure 14. When the BHF is raised beyond 40kN, the full draw could not be done in case of oil coated substrate whereas the full draw could be done up to 60kN for the substrate coated with present hybrid coating formulation. The comparative displacement of the cups between oil and the hybrid coating is shown in said Figure 14. The percentage of reduction in punch load in case of hybrid coating is varied by 5-8 kN with the same BHF. The BHF reduction data is clearly visible in the graph.

Further, different portions of the cup were studied by SEM and EDX. It was observed that the coating at base and neck persists. EDX data still showed the peaks of Zr and V. Peaks with C, and O were significantly reduced. However, in case of bent and side portions of the cup, these peaks associated with Zr, V, C and O significantly reduced. This indicated that there is a film rupture.

In case of dome test, the coated sheet was drawn till 40 mm. Visually there was no peel off in the film. Even on rubbing with tissue paper, no film rapture was observed. When the dome was exposed in SEM, it is observed that there is no discontinuity in the film due to the deformation on the sheet. From EDX data, the presence of Zr peak was also confirmed.

The above results indicate the achievement of corrosion protecting film on the metal surface. The coated sheet undergoes different forming operations in the plant and at the site of end use customers. Forming is an inhabitable part for the appliances and automotive industry. In roofing industry, corrugation is one of the most important operation in steel plants. During these operations, if sufficient lubricity is not present, there may be film rupturing, peel off and/or crack formation. Hence, additional corrosion tests were carried out on galvanized substrate coated with present hybrid coating formulation before and after the forming operation. By testing with ASTM B117, the galvanized sheet coated with hybrid coating achieved 144-192 hours in NSST (Figure 15) with the variation of coating weight 1-1.5 g/m2/side. On the other hand, when the same substrate on which dome test was conducted was exposed to NSST, the salt spray achieved up to 72 hours with less than 2% white rust (Figure 15 B). Further, the sample which was subjected to cupping test was also exposed to neutral salt spray test (NSST). It was observed that there was 0% corrosion on the base of the cup. Neck was covered with cello tape. However, at neck and side portion of the cup, there was more than 5% corrosion. This further validates the findings of EDX where it was observed that at base, Zr and V exists, but at side and neck portions, no Zr or Vanadium peaks were found.

EXAMPLE 3: Synthesis of Ti based hybrid coating formulation
A series of Ti based hybrid coating formulations based on the organometallic complex ammonium titanium lactate (formed by reaction of Ti source and lactic acid) and polyacrylate (polymeric resin) along with other additives were prepared. The prepared formulations are listed below:

Table 7: Formulations of Ti based coating formulations according to present disclosure
Ingredients F1 F2 F3 F4 F5 F6 F7 F8 F9 F10
QC100 (Polyacrylate) 40 40 40 40 40 40 40 40 40 40
Aquaslip 682 (polyethylene wax) 5 5 5 5 5 5 5 5 5 5
KH570 (methacrylsilane) 0 0 0 0 0 0.2 0.4 0.6 0.8 1
Ammonium Titanium Lactate (organometallic complex) 5 10 15 20 25 10 10 10 10 10
Demineralised Water (DM) water 50 45 40 35 30 34.8 34.6 34.4 34.2 34

EXAMPLE 4: Characterization and Activity Study of Ti based hybrid coating formulation according to the present disclosure
Formulation F9 of Table 7 was further studied/characterized as follows:

X-ray Diffraction Study
The coated sheet was analysed by absolute scan in XRD and crystalline peaks were found (Figure 16). These peaks were mainly identified as Silicon Titanium (3/5) and Titanium Zinc (1/2).

X-ray Photoelectron Spectroscopy (XPS):
In XPS, the scan was run in the range of binding energy -10 to 1400 eV (Figure 17). Sharp peak of Ti was observed at 460 eV (Figure 17B). Similarly, at 530 eV, the binding energy of O was observed indicating the presence of TiO2 (Figure 17C).

Microscopy
Scanning Electron Microscope (SEM) was used to understand the morphology of the coating system. Crystalline structure was observed in the micrographs for the coated system (Figure 18). Energy Dispersive Spectroscopy (EDS) analysis shows the presence of C, O, Zn, Ti, Si across the test area (Figure 19). Surface mapping indicates that Ti, Si, O are uniformly distributed throughout the matrix. This is because, on curing, the organometallic compound forms bond and gets crosslinked with the functional group (mostly carboxylic group and -OH group) present in the polymer moiety. The area where crystalline structures are found are rich in O and also metals. This confirms that the crystals which are formed in the coating are compounds of Ti and O. Scanning Electron Microscope was used understand the morphology of the coating system. In SEM, when the coated strip is analyzed under SEM in a magnification scale of 5000X, some randomly oriented rod-like crystalline structure was observed (Figure 20). By analysis at different portions, with EDX, peaks associated with C, O, Zn, Ti, Si are mainly found (Figure 21).

Forming test
Activity/property studies were conducted using both Ti based hybrid coating formulation (formulation F9 of Table 7 and designated as Ti-H coat in the present example) and Zr & V based hybrid coating formulation (designated as Zi-H coat in the present example), respectively, of the present disclosure.

GA samples (210*297*0.78mm) were cleaned with silicate free alkaline degreasing solution and subsequently coated with Ti based hybrid coating formulation of Example 3/Table 7. Standard 100 mm diameter blanks were machined out from coated as well as uncoated GA sheets for cupping tests. Formability tests were conducted on a 60T servo-hydraulic forming press by varying the blank holding force and the resultant punch force and displacement was measured. Cupping test was performed in GA sheet coated with either of the Ti-H or Zi-H hybrid coating formulation, and GA sheet coated with cutting oil. Corrosion tests were performed by exposing the material before and after forming operation in Neutral Salt Spray test (NSST) by ASTM B117. Dynamic contact resistance was also studied for the samples.

Results of Forming test
When cupping test was carried out, it was observed that with the same blank holding force, there is a significant reduction of punch load in GA sheet coated with the present hybrid coating formulations (Ti-H coat or Zi-H coat) when compared to cutting oil coated GA sheet with same thickness. NSST results indicate that GA coated the present hybrid coating formulations Ti-H or Zr-H give a significantly greater NSST life compared to uncoated/cutting oil coated GA. Particularly, Zr-H coat gave 192 hours NSST Life and Ti-H coat gave almost 300 hours NSST Life. After forming, Zr-H coat gave 72 hours NSST and Ti-H coat gave 240 hours of NSST (Figures 23A and 23B).

Further, dynamic contact resistance of the present hybrid coating formulations indicate good weldability compared to uncoated/bare GA (Figure 22). Particularly, dynamic contact resistance of the Ti based hybrid coating (Ti-H coat) was 1.2 milliohm which indicates excellent weldability.

The above results thus indicate the achievement of corrosion protecting film on the metal surface when the present Ti based and Zr-V based hybrid coating formulations are employed on galvanized or galvannealed steel substrate.

Conclusion of Examples 1-4:
Heavy metals such as V, Zr and Ti were employed in the above examples to prepare a series of hybrid coating formulations according to the present disclosure. The primary technical challenge of instability/precipitation of heavy metals in polymeric resin based coatings was particularly addressed. For instance, when the pH of a formulation containing heavy metal(s) is increased to make the system compatible with polymeric resins, there is a precipitation of the heavy metals. Second problem is, in hybrid technology, polymeric resins such as polyacrylate and polyurethane which have the properties of crosslinking get precipitated at low pH. Hence, it is very necessary to address the issue of compatibility of the hybrid coating system.

Accordingly, to address the above problems, organic acid(s) as sequestering agents were employed to prepare organometallic complexes with heavy metal(s). Such organometallic complexes formed by the reaction of organic acids (eg. lactic acid) and heavy metals are stable at a very wide range of pH. Particularly, the organometallic complex formed by the reactions between V, Zr and lactic acid was incorporated in the polyacrylate resin and polyethylene wax moiety along with other additives as described in Example 1. Similarly, the organometallic complex formed by the reaction between Ti and lactic acid was incorporated in the polyacrylate resin and polyethylene wax moiety along with other additives as described in Example 3. As a result, stable formulations without any deformation or precipitation were formed.

The prepared organometallic compounds/complexes are very stable in the entire range of pH 2-10. Further, during the synthesis of organometallic complexes according to the present disclosure, both single heavy metal (eg. Ti as employed in Example 3) or multiple heavy metals (eg. V and Zr as employed in Example 1) can be used. When multiple heavy metals are used, organometallic complexes containing multiple heavy metals are formed. This further gives an additional advantage during different mechanical operations and corrosion behaviour.

The single or multi-metallic organometallic complexes remain stable in the hybrid coating formulation surrounded by the environment of polymers, wax and other additives. In order to bring the stability, pH also plays a vital role. The formulation needs to be designed considering the pH range of both polymer and the organometallic complex, otherwise there is a chance of precipitation/instability. For instance, if the pH of the organometallic compound and the polymer remains the same, there is no precipitation/destabilisation observed during manufacturing of the compound. The functional groups present in the polymer will not react with the organometallic compound at room temperature. Said fact was established by FTIR study of the V and Zr based formulations. No carboxylate-metal salt peaks were found in the product. The crosslinking reaction occurs when the coating film is cured at elevated temperature in presence of zinc of galvanized steel sheet. The evidence of different chemical reactions were observed during the curing reaction. FTIR and Raman spectra showed that there are new C=O, C-O, C-O-C- bonds formed. There are also new Si-O, -O-Si-O-, -Si-O-C- bonds formed; and carboxylate metal salt peaks are also generated. Another important observation was the metal oxides being coated on the galvanized steel substrate. These metal oxides are crystalline in nature and can be detected by XRD. Some of these crystals contain unit cell with multi-metals in case of formulations which employed both V and Zr. In addition, Zn-Si bonds were also found. XPS also confirmed the presence of metal oxides. These metal oxides showed beautiful needle like crystals in SEM. From EDS and XRD, it was confirmed that the crystallinity entirely lies with the metal oxides. TEM analysis of the hybrid coating film contained both amorphous organic moiety with crystalline metal oxides. In XRD, when the film coated on glass was analysed, there was no sign of crystallinity. Thus, it is confirmed from the above evidence that when Zn metal is at elevated temperature, crosslinking reaction happens. As a result, new cross-linked bonds are generated.

Further, the corrosion resistance property is primarily achieved based on metal oxides wherein the metal(s) are stably incorporated into the polymeric resin matrix. Additionally, since the metals are distributed all over the film as carboxylate salts, these metals are capable of healing process whenever there is any film rupture such as during forming operations. In other words, the present coating formulation/system is capable of providing corrosion resistance even after forming operations. Consequently, the film network can still be seen after forming in SEM and also excellent corrosion resistance is achieved during or post forming operations.

Based on the above examples/evidence, the present disclosure shows as to how organometallic complexes can be successfully formed and utilized in coating formulation systems comprising crosslinking polymer and optionally lubricating wax and other additive(s). The present hybrid coating formulation is a flexible, lubricating thin film which is formable and having excellent corrosion resistance. As discussed above, this type of coating system/film is capable of providing specific functionalities such as corrosion resistance even after forming operation along with the characteristics of weldability or paintability. The film is also capable of imparting lubricity to the metal which makes the hybrid formulation coated galvanized sheet more drawable than the RP oil/cutting oil coated sheet or uncoated/bare sheet.

Additionally, it is evident from the above examples/evidence that the present coating formulation/system provides advantages/improvement as discussed above. Particularly, the feature of incorporating heavy metal(s) in organic resin(s) as organometallic complex/compound is able to address the compatibility/stability issue which occurs when heavy metals or corresponding salts are simply added/admixed with water based organic resin(s). In other words, mere admixing of the heavy metals or corresponding salts with water based organic resin(s) will lead to incompatible/poorly soluble/unstable formulation and such formulation is not applicable/useful when further coated onto metal substrates such as GA steel. Further, dissolving heavy metal sources in inorganic acids and incorporating the same in water based organic resin(s) also lead to incompatible/poorly soluble/unstable formulation. For instance, when a source of zirconium (eg. hexafluoro zirconic acid) or a source of vanadium was dissolved in inorganic acid(s), the pH obtained was less than 2. Most of the water based polycrylate and polyurethane systems get precipitated when said Zr and V sources are employed. Additionally, when the pH of inorganic solution was increased, it gets precipitated as hydroxides. Thus, it is the technical effect of the single metal or multi-metallic organometallic complex with the organic resin(s) which is able to address the stability/precipitation issue along with achieving advantages such as usefulness of the present hybrid coating formulation at wide pH, imparting corrosion resistance etc.

Thus, the present disclosure is successful in finding a successful replacement for hexavalent chrome free passivation and other currently employed coating formulations for providing corrosion resistance to substrate such as galvanized or galvannealed steel sheet. The presently developed hybrid coating formulation based on incorporation of heavy metals into resin matrix as organometallic complexes is immensely advantageous in terms of compatibility, stability and corrosion resistance, especially in relation to steel making.

INCORPORATION BY REFERENCE
All references, articles, publications, patents, patent publications, and patent applications (if any) cited herein are incorporated by reference in their entireties for all purposes. However, mention of any reference, article, publication, patent, patent publication, and patent application cited herein is not, and should not be taken as, an acknowledgment or any form of suggestion that they constitute valid prior art or form part of the common general knowledge in any country in the world.