Claims:WE CLAIM:
1. A composition comprising shellac, resin, crosslinking agent and solvent, optionally along with graphene.

2. The composition as claimed in claim 1, wherein the resin is selected from a group comprising epoxy, Polyethylene glycol, polyvinyl acetate and acrylic resin, or any combination thereof.

3. The composition as claimed in claim 1, wherein the crosslinking agent is selected from a group comprising cyclohexylamine, pentylamine, butylamine and 1, 3-propanediamine or any combination thereof.

4. The composition as claimed in claim 1, wherein the solvent is selected from a group comprising isopropanol, formaldehyde, ethanol and butyl cellosolve, or any combination thereof.

5. The composition as claimed in claim 1, wherein the graphene is selected from a group comprising graphene oxide and reduced graphene oxide, or a combination thereof.

6. The composition as claimed in claim 1, wherein the shellac is at a concentration ranging from about 8% to 10%; the resin is at a concentration ranging from about 8% to 16%; the crosslinking agent is at a concentration ranging from about 3% to 5%; the solvent is at a concentration ranging from about 4% to 69%; and the graphene is a concentration ranging from about 0.01% to 0.05%.

7. The composition as claimed in claim 1, wherein ratio of the shellac and the resin is ranging from about 0.5:1 to 1:5.

8. The composition as claimed in claim 1, wherein the composition covers pores on graphene coated substrate and suppresses corrosion rate of the graphene coated substrate by about 104 times; wherein the substrate is selected from a group comprising metal and alloy and wherein the metal is selected from a group comprising iron, copper, tin, zinc and aluminum, or any combination thereof and alloy is selected from a group comprising steel, brass and pewter, or any combination thereof.

9. A process for preparing the composition of claim 1, said process comprising steps of:
adding the shellac to solvent-A to obtain a solution; and
adding the resin and the crosslinking agent, optionally along with solvent-B and the graphene to the solution, followed by mixing to obtain the composition.

10. The process as claimed in claim 9, wherein the solvent-A is selected from a group comprising isopropanol, ethanol, and butanol, or any combination thereof; and the solvent-B is selected from a group comprising formaldehyde, and butyl cellosolve, or a combination thereof.

11. The process as claimed in claim 9, wherein the mixing is carried out at about 100rmp to 600rpm, at a temperature ranging from about 60ºC to 120o C.

12. A process for coating the composition of claim 1 on a substrate, said process comprising step of contacting the substrate with the composition, followed by curing the substrate having the composition.

13. The process as claimed in claim 12, wherein the substrate is contacted with the composition by technique selected from a group comprising dip coating, spray, roll coating, and slot coating, or any combination thereof.

14. The process as claimed in claim 12, wherein the curing is carried out at a temperature ranging from about 200ºC to 400ºC for a period of about 1 minute to 20 minutes.

15. The process as claimed in claim 12, wherein the substrate is selected from a group comprising metal and alloy; wherein the metal is selected from a group comprising iron, copper, aluminum, zinc and tin, or any combination thereof; wherein the alloy is selected from a group comprising steel, brass, bronze and pewter, or any combination thereof; and wherein the substrate is graphene coated.

16. The process as claimed in claim 12, wherein thickness of the composition on the substrate is about 20nm to 300nm.

17. The process as claimed in claim 12, wherein the process causes the composition to cover pores on graphene coated substrate and thereby suppresses corrosion rate and red rusting initiation time of the substrate and wherein the process suppresses the corrosion rate by about 104 times.

18. The process as claimed in the claim 17, wherein the corrosion rate of the substrate coated with the composition is about 0.000007mm/year to 0.000059 mm/year. , Description:TECHNICAL FIELD
The present disclosure relates to a composition comprising shellac, resin, crosslinking agent and solvent, optionally along with graphene and to a process of preparing the said composition. The disclosure further relates to a process of coating the said composition to suppress the corrosion rate of the substrate.

BACKGROUND OF THE DISCLOSURE
Graphene has poor corrosion protective action on a substrate as compared to organic and inorganic coating materials used for improvement in the anti-corrosion properties of metals in saline environment. The poor anti-corrosion properties of graphene are attributed to the defects observed with the graphene and the pores formed within the graphene during coating on a substrate. There are several techniques reported which are believed to reduce the quantity of pores and improve the anti-corrosion properties of the graphene coated substrate, the techniques are vapor phase treatment, intermolecular dehydrogenation, annealing of graphene in gaseous condition, annealing of graphene at high temperature. However, described techniques have their own limitation in terms of the strength of the anti-corrosion properties imparted to graphene coated substrate and the said techniques also have a limitation in imparting anti-corrosion properties to industrially produced graphene coated substrates. Thus, there appears to be a need to obtain a graphene coated substrate having improved and better anti-corrosion properties.

SUMMARY OF THE DISCLOSURE
Accordingly, the present disclosure relates to a composition comprising shellac, resin, crosslinking agent and solvent, optionally along with graphene.

In another embodiment, the present disclosure relates to a process for preparing the composition, said process comprising steps of:
adding the shellac to solvent-A to obtain a solution; and
adding the resin and the crosslinking agent, optionally along with solvent-B and the graphene oxide to the solution, followed by mixing to obtain the composition.

In another embodiment, the present disclosure relates to a process for coating the composition on a substrate, said process comprising step of contacting the substrate with the composition, followed by curing the substrate having the composition.
BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURES
In order that the disclosure may be readily understood and put into practical effect, reference will now be made to exemplary embodiments as illustrated with reference to the accompanying figures. The figures together with detailed description below, are incorporated in and form part of the specification, and serve to further illustrate the embodiments and explain various principles and advantages, in accordance with the present disclosure where:

FIGURE 1 illustrates XPS and SEM data of graphene oxide coated substrate.

FIGURE 2 illustrates Tafel data of bare CRS sheet (a), graphene oxide coated CRS sheet (b) and graphene oxide coated CRS sheet having the composition of the present disclosure.

FIGURE 3 illustrates salt spray data of (a) bare substrate after 6 hr exposure, (b) of substrate coated with the composition of the present disclosure after 300 hr exposure.

DETAILED DESCRIPTION
The present disclosure relates to a composition comprising shellac, resin, crosslinking agent and solvent, optionally along with graphene.

In an embodiment of the present disclosure, the resin is selected from a group comprising epoxy, polyethylene glycol, polyvinyl acetate and Acrylic resin, or any combination thereof.

In an embodiment of the present disclosure, the crosslinking agent is alkyl amine containing alkyl group having about C2 to C6 carbon atoms.

In another embodiment of the present disclosure, the crosslinking agent is selected from a group comprising cyclohexylamine, pentylamine, butylamine and 1,3-propanediamine, or any combination thereof.

In another embodiment of the present disclosure, the solvent in selected from a group comprising isopropanol, formaldehyde, ethanol, butanoland butyl cellosolve, or any combination thereof.

In another embodiment of the present disclosure, the graphene is selected from a group comprising graphene oxide and reduced graphene oxide or a combination thereof.

In an embodiment, in the composition of the present disclosure, the shellac is at concentration ranging from about 8% to 10%.

In another embodiment, in the composition of the present disclosure, the resin is at a concentration ranging from about 8% to 16%.

In another embodiment, in the composition of the present disclosure, the crosslinking agent is at a concentration ranging from about 3% to 5%.

In another embodiment, in the composition of the present disclosure, the solvent is at a concentration ranging from about 4% to 69%.

In another embodiment, in the composition of the present disclosure, the graphene is at a concentration ranging from about 0.01% to 0.05%.

In an embodiment, in the composition of the present disclosure, ratio of the shellac and the resin is ranging from about 0.5:1 to 1:5.

In an exemplary embodiment, the composition of the present disclosure comprises shellac, epoxy resin, crosslinking agent, formaldehyde and isopropanol.

In another exemplary embodiment, the composition of the present disclosure comprises shellac, epoxy resin, crosslinking agent, graphene and isopropanol.

In an embodiment, the composition of the present disclosure is in a solution form.

In an embodiment, the composition of the present disclosure imparts anticorrosion property to a substrate, upon coating the substrate with the composition.

In an embodiment, the composition of the present disclosure imparts anticorrosion property to a substrate in saline environment.

In an embodiment, the composition of the present disclosure suppresses the corrosion rate of a substrate by about 104 times.

In another embodiment, the composition of the present disclosure suppresses the corrosion rate of a graphene coated substrate by about 104 times.
In another embodiment, the composition of the present disclosure covers or shields the pores of graphene coated substrates, thereby preventing the corrosion of the substrate.

In an exemplary embodiment, the composition of the present disclosure suppresses the corrosion rate of graphene coated cold rolled steel (CRS) sheets by more than 104 times.

In another exemplary embodiment, the composition of the present disclosure covers or shields the pores of graphene coated cold rolled steel (CRS) sheets, thereby preventing the corrosion of the CRS sheets.

In an embodiment, in the composition of the present disclosure, there is a synergistic effect of graphene oxide and shellac. The shellac solution composed of long chain organic molecules with hydroxyl (-OH) and carboxylic acid (-COOH) functional groups block the pores that are formed during the production of graphene coated substrate. The presence of hetero atoms in the shellac leads to form strong bond on the metal surface, which is caused by the lone pair electrons. These lone pair of electrons gets fused with the functional groups of graphene oxide. Thereby, the composition shields or covers the pores of the substrate pre-coated with graphene and makes the substrate resistant to corrosion.

The present disclosure further relates to a process of preparing the composition described above.

In an embodiment, the composition is prepared by mixing shellac, resin, crosslinking agent and solvent, optionally along with graphene.

In an embodiment, the process of preparing the composition comprises steps of
adding shellac to solvent-A to obtain a solution; and
adding resin and crosslinking agent, optionally along with solvent-B and graphene to the solution, followed by mixing to obtain the composition.

In an embodiment, the mixing is carried out at about 100rpm to 600rpm, at a temperature ranging from about 60ºC to 120oC.

In an embodiment, in the process of the preparing the composition of the present disclosure, the resin is selected from a group comprising epoxy, polyethylene glycol, polyvinyl acetate and acrylic resin, or any combination thereof; the crosslinking agent is selected from a group comprising cyclohexylamine, pentylamine, butylamine and 1, 3-propanediamine, or any combination thereof; the solvent is selected from a group comprising isopropanol, formaldehyde, ethanol, butanol and butyl cellosolve, or any combination thereof; and the graphene is selected from a group comprising graphene oxide and reduced graphene oxide, or a combination thereof.

In an embodiment, in the process of the present disclosure, the solvent-A is selected from a group comprising isopropanol, ethanol and butanol, or any combination thereof.

In another embodiment, in the process of the present disclosure, solvent-B is selected from a group comprising formaldehyde and butyl cellosolve, or a combination thereof.

In an embodiment, in the process of the preparing the composition of the present disclosure, the shellac is at a concentration ranging from about 8% to 10%; the resin is at a concentration ranging from about 8% to 16%; the crosslinking agent is at a concentration ranging from about 3% to 5%; the solvent is at a concentration ranging from about 4% to69%; and the graphene is at a concentration ranging from about 0.01% to 0.05%;

In an exemplary embodiment, the solvent-A including but not limiting to isopropanol, ethanol and butanol is at a concentration of about 69%.

In another exemplary embodiment, the solvent-B including but not limiting to formaldehyde and butyl cellosolve is at a concentration of about 4%.

In an embodiment, in the process of preparing the composition of the present disclosure, ratio of the shellac and the resin is ranging from about 0.5:1 to 1:5.

The present disclosure further relates to a process of coating the composition of the present disclosure on a substrate.

In an embodiment, the process of coating the substrate with the composition of the present disclosure comprises a step of contacting the substrate with the composition, followed by curing the substrate having the composition.

In an embodiment, the substrate is contacted with the composition by techniques including but not limiting to dip coating, spray, roll coating and slot coating, or any combination thereof.

In an exemplary embodiment, the substrate is contacted with the composition by dip coating, wherein the substrate is contacted with the composition by dipping the substrate in the composition for about 1 to 20 times, followed by drying in the air atmosphere for a period of about 1 to 10 minutes after each dipping.

In another exemplary embodiment, the substrate coated with the composition is cured at a temperature ranging from about 200ºC to 400ºC in air for a period of about 1 minute to 20 minutes. The curing is performed after contacting the substrate with the composition.

In an alternate exemplary embodiment, the substrate coated with the composition is cured in electro-heating furnace at a temperature ranging from about 200ºC to 400ºC for a period of about 1 minute to 20 minutes.

In an embodiment, the thickness of the composition on the substrate is varied based on the number of times the substrate is dipped in the composition while dip coating.

In an exemplary embodiment, the thickness of the composition on the substrate is ranging from about 20nm to 300nm.

In an embodiment, the substrate includes but not limiting to metal and alloy, wherein the metal selected from a group comprising iron, copper, tin, zinc and aluminium, or any combination thereof; and wherein the alloy is selected from a group comprising steel, brass, and pewter, or any combination thereof.

In an embodiment, the substrate is pre-coated with graphene.

In another embodiment, the substrate is pre-coated with graphene oxide or reduced graphene oxide or with a combination of graphene oxide or reduced graphene oxide.

In an embodiment, the process of coating the composition on the substrate covers or shields the pores that are contained on the surface of graphene pre-coated substrate, thereby suppresses the corrosion rate and red rusting initiation time of the graphene pre-coated substrate.

In another embodiment, the process of coating the composition on the substrate suppresses the corrosion rate and red rusting initiation time of the graphene pre-coated substrate in saline environment.

In an embodiment, the process of coating the composition on the substrate suppresses the corrosion rate of the substrate by about 104 times and suppresses red rusting initiating time.

In an embodiment, the process of coating the composition on steel including but not limiting to cold rolled steel (CRS) sheets, suppresses the corrosion rate of the CRS sheets by about 104 times and suppresses red rusting initiating time of the CRS sheets. In an exemplary embodiment, the cold rolled steel is pre-coated with graphene.

In an embodiment, in the process of coating the composition on substrate pre-coated with graphene oxide, there is a synergistic effect of graphene and shellac. The shellac is composed of long chain organic molecules with hydroxyl (-OH) and carboxylic acid (-COOH) functional groups block the pores that are formed during the production of graphene oxide coated substrate. The presence of hetero atoms in the shellac leads to form strong bond on the metal surface, which is caused by the lone pair electrons. These lone pair of electrons get fused with the functional groups of graphene oxide during curing. Thereby, the process enables to shield or cover the pores of the graphene oxide pre-coated substrate.

In an embodiment, the process of coating the composition on the substrate enables coating of the composition on large area substrate. The process also enables coating the composition on industrially produced substrate pre-coated with graphene oxide.

Additional embodiments and features of the present disclosure will be apparent to one of ordinary skill in art based upon the description provided. The embodiments 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. The examples provided herein are intended merely to facilitate an understanding of ways in which the embodiments provided may be practiced and to further enable those of skill in the art to practice the embodiments provided. Accordingly, the following examples should not be construed as limiting the scope of the embodiments.

EXAMPLES

EXAMPLE 1: Process of preparing graphene pre-coated substrate.
Shellac solution is prepared by adding about 1g to 2g shellac in about 100ml to 500ml isopropanol solvent at a temperature ranging from about 60ºC to 90ºC. NiCl2-shellac solution is made by adding about 0.001g to 0.1g NiCl2 in about 100ml to 1000ml shellac solution. The resulting solution is coated over the surface of a substrate (CRS sheet) by dip coating, followed by air drying at a temperature ranging from about 20ºC to 40ºC. The coated substrate is heated using a batch annealing furnace at a temperature ranging from about 400ºC to 1200ºC under controlled atmosphere of hydrogen at the flow rate of 100sccm to 500sccm for a period of about 10 minutes to 120 minutes. The obtained coated substrate is characterized using Raman spectroscopy and X-ray photoelectron spectroscopy, indicating formation of graphene on the surface of the substrate.

EXAMPLE 2: Process preparing composition of the present disclosure.
About 80g to 100g of processed shellac is added to about 1000ml of isopropanol solvent at a temperature ranging from about 60ºC to 90ºC to obtain shellac solution. About 80ml to 160ml of epoxy resin, about 40ml of formaldehyde and about 30 ml of crosslinking agent are added to shellac solution under mixing at about 400 rpm, at a temperature of about 60ºC to obtain the composition.

EXAMPLE 3: Process of coating the composition prepared in Example 2.
The substrate (CRS sheet) pre-coated with graphene is dipped into the composition obtained in Example 2, followed by air drying the composition coated substrate at a temperature of about 20ºC to 40ºC. The thickness of the coating of the composition on the substrate is varied by the number of dips of the substrate into the composition. The composition coated substrate is heated using an electro-heating furnace at a temperature ranging from about 200ºC to 400ºC for a period of about 5 minutes to 120 minutes.
The substrate (CRS sheet) coated with the composition, bare substrate and substrate pre-coated with graphene are subjected to electro-chemical test and salt spray test to assess the efficacy of the composition coated on the substrate. The results obtained for each of the said substrates from the said tests is compared. The compared result shows that the composition coated substrate shows improvement in corrosion resistance properties, indicating that the composition coated on the substrate shields the pores on the graphene pre-coated substrate.
The tafel data shows (illustrated in FIGURE 2) that the composition (obtained from Example-2) coated substrate pre-coated with graphene has a corrosion rate of about 0.000059mm/year, whereas the bare substrate has a corrosion rate of about 0.1069mm/year and the substrate pre-coated with graphene has a corrosion rate of about 0.106mm/year. Thereby, evidently indicating that the composition coated substrate has improved corrosion suppression property.

EXAMPLE 3: Process preparing composition of the present disclosure.
About 80g to 100g of processed shellac is added to about 1000ml of isopropanol solvent at a temperature ranging from about 60ºC to 90ºC to obtain shellac solution. About 80ml to 160ml of epoxy resin, about 30 ml of crosslinking agent and about 0.2g of graphene are added to shellac solution under mixing at about 400 rpm, at a temperature of about 60ºC to obtain the composition of the present disclosure.

EXAMPLE 4: Process of coating the composition prepared in Example 3.
The substrate (CRS sheet) pre-coated with graphene is dipped into the composition obtained in Example 3, followed by air drying the composition coated substrate at a temperature of about 20ºC to 40ºC. The thickness of the coating of the composition on the substrate is varied by the number of dips of the substrate into the composition. The composition coated substrate is heated using an electro-heating furnace at a temperature ranging from about 200ºC to 400ºC for a period of about 5 minutes to 120 minutes.
The substrate (CRS sheet) coated with the composition, bare substrate and substrate pre-coated with graphene are subjected to electro-chemical test and salt spray test to assess the efficacy of the composition coated on the substrate. The results obtained for each of the said substrates from the said tests is compared. The compared result shows that the composition coated substrate shows improvement in corrosion resistance properties, indicating that the composition coated on the substrate shields the pores on the graphene pre-coated substrate.
The tafel data shows (illustrated in FIGURE 2) that the composition (obtained from Example-3) coated substrate pre-coated with graphene has a corrosion rate of about 0.000007mm/year, whereas the bare substrate has a corrosion rate of about 0.1069mm/year and the substrate pre-coated with graphene has a corrosion rate of about 0.106mm/year. Thereby, evidently indicating that the composition coated substrate has improved corrosion suppression property.

Additional embodiments and features of the present disclosure is 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. Throughout this specification, the word “comprise”, or variations such as “comprises” or “comprising” 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. 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. Any discussion of documents, acts, materials, devices, articles and the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application. 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.