Description:FIELD
The present disclosure relates to a silicone grafted cardanol modified epoxy urethane resin and a coating composition obtained therefrom. Particularly, the present disclosure relates to an anti-corrosive coating composition comprising a silicone grafted cardanol modified epoxy urethane resin. Further, the present disclosure also relates to a process of preparing the silicone grafted cardanol modified epoxy urethane resin.
DEFINITIONS
As used in the present disclosure, the following terms are generally intended to have the meaning as set forth below, except to the extent that the context in which they are used indicates otherwise.
Salt spray testing (SST) refers to an accelerated corrosion test that produces a corrosive attack on coated samples in order to evaluate the suitability of the coating for use as a protective finish. It is known as a salt spray test (or salt fog test). ASTM B 117 is one of the methods to carry out such test.
ASTM B117 is one of the methods to carry out a corrosion test designed to provide corrosion resistance information on metals and coated metals.
Dry film thickness (DFT) refers to a thickness of a coating on the substrate, for a single layer or multiple layers. DFT is measured for cured coatings.
Stoving system refers to a system in which electricity or fuel is used to furnish heat.
Air drying system refers to a system in which moisture from surfaces and coatings is removed by using air (forced, dry or hot).
Epoxy equivalent weight (EEW) refers to the number of grams of epoxy resin required to give 1 epoxy group.
BACKGROUND
The background information herein below relates to the present disclosure but is not necessarily prior art.
Metal substrates and related parts in industrial environments are in contact to a number of acids and bases due to the variety of compositions that pass through, or are contained therein. In some cases, sulphuric acid is generated due to the industrial process and the gas is caused to exit a smokestack on a substantially constant basis. Often, the only way to avoid the corrosive nature of such acids or bases is to completely scrap the article after a period of use. Alternatively, the use of the article can be discontinued so that a lengthy cleaning can occur. Such alternatives are expensive and can lead to long down times caused by replacement or discontinued use.
Conventionally used compositions for reducing corrosion are majorly based on film-forming polymeric organic polymers. Further, such compositions also contain a mixture of pigments and extender solids, at least one of which is effective in retarding corrosion of the substrate metal. Pigments containing lead, particular red lead, and hexavalent chromium, for instance, zinc potassium chromate are efficient anti-corrosive pigments and have been widely used with success. However, due to the highly toxic nature of lead and hexavalent chromium, their use is restricted and hence they are replaced with alternative materials. However, such alternative material does not have a performance matching that of lead and hexavalent chromium. Further, zinc phosphate is considered non-toxic and is extensively used as an anti-corrosive pigment. However, deficiencies in the performance of zinc phosphate are widely reported, in particular its inability to prevent rust creep from damages in the coating. Although slightly soluble metal salts of organic acids are extensively used as corrosion inhibiting additives in aqueous reservoir systems, surprisingly these materials are not widely used as corrosion inhibiting pigments in the surface coating compositions. Still, further, the use of barium salts of hydroxy carboxylic acid such as salicylic acid (barium salicylic) has also been reported. However, barium salicylate is soluble in water at a level greater than 10% w/w, and hence it is liable to leach from the coating containing barium salicylate.
Therefore there is a need to develop an anti-corrosive composition that utilizes a compound which mitigates the drawbacks hereinabove or at least provides a useful alternative.
OBJECTS
Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows:
An object of the present disclosure is to ameliorate one or more problems of the prior art or to at least provide a useful alternative.
An object of the present disclosure is to provide a silicone grafted cardanol modified epoxy urethane resin.
Another object of the present disclosure is to provide a silicone grafted cardanol modified epoxy urethane resin that is used in the anti-corrosive composition.
Yet another object of the present disclosure is to provide a process for preparing the silicone grafted cardanol modified epoxy urethane resin.
Another object of the present disclosure is to provide an anti-corrosive composition that can be used as a thin-film corrosion-resistant coating in paints.
Still another object of the present disclosure is to provide an anti-corrosive composition that has better corrosion resistance.
Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.

SUMMARY
The present disclosure relates to a silicone grafted cardanol modified epoxy urethane resin and a coating composition obtained therefrom. Particularly, the present disclosure relates to an anti-corrosive coating composition comprising a silicone grafted cardanol modified epoxy urethane resin. Further, the present disclosure also relates to a process of preparing the silicone grafted cardanol modified epoxy urethane resin.

In an aspect, the silicone grafted cardanol modified epoxy urethane resin comprises a reaction product of cardanol modified epoxy resin having epoxide equivalent weight 3000-5000, a polyisocyanate, and a silicone resin. The silicone grafted cardanol modified epoxy urethane resin is characterized by a clear solution having an average molecular weight in the range of 20000 to 60000 g/mole.

In another aspect, the present disclosure relates to a process for preparing a silicone grafted cardanol modified epoxy urethane resin. The process comprises reacting predetermined amounts of an epoxy resin and a cardanol in the presence of a catalyst at a first predetermined temperature for a first predetermined time period to obtain a reaction mixture. The temperature of the reaction mixture is raised in the range of 175°C to 225°C to obtain a reaction mass. Further, the temperature of the reaction mass is raised in the range of 210°C to 250°C and maintained the temperature till a viscosity of R-W at 25°C on the Gardner scale is achieved to obtain a resultant mass. The resultant mass is cooled at a temperature in the range of 125°C to 200°C followed by diluting it with a predetermined amount of a first fluid medium to obtain a cardanol modified epoxy resin. The cardanol modified epoxy resin is reacted with a polyisocyanate at a second predetermined temperature for a second predetermined time period to achieve a constant viscosity at 25oC to obtain a cardanol modified epoxy urethane resin. The cardanol modified epoxy urethane resin is reacted with a silicone resin in the first fluid medium at a third predetermined temperature for a third predetermined time period till the reaction mass becomes transparent and the viscosity at 25°C is achieved to obtain the silicon grafted cardanol modified epoxy urethane resin.
In still another aspect, the present disclosure relates to an anti-corrosive composition. The anti-corrosive composition comprises a binder in an amount in the range of 40 to 45 mass% with respect to the total mass of the composition, an anti-corrosive pigment in an amount in the range of 5 to 7 mass% with respect to the total mass of the composition, a pigment in an amount in the range of 5 to 7 mass% with respect to the total mass of the composition, an extender in an amount in the range of 18 to 25 mass% with respect to the total mass of the composition, a crosslinker in an amount in the range of 5 to 10 mass% with respect to the total mass of the composition, a dispersing agent in an amount in the range of 0.5 to 1 mass% with respect to the total mass of the composition, and a solvent in an amount in the range of 25 to 27 mass% with respect to the total mass of the composition.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
The present disclosure will now be described with the help of the accompanying drawing, in which:
Figure 1 shows a pictorial representation of corrosion resistance as per ASTM B 117 at 250 hrs by using an air-drying system in accordance with the present disclosure;
Figure 2 shows a pictorial representation of corrosion resistance as per ASTM B 117 at 500 hrs by using the air-drying system in accordance with the present disclosure;
Figure 3 shows a pictorial representation of corrosion resistance as per ASTM B 117 at 750 hrs by using the air-drying system in accordance with the present disclosure;
Figure 4 shows a pictorial representation of corrosion resistance as per ASTM B 117 at 1000 hrs by using the air-drying system in accordance with the present disclosure;
Figure 5 shows a pictorial representation of corrosion resistance as per ASTM B 117 post tape test at 1000 hrs by using the air-drying system in accordance with the present disclosure;
Figure 6 shows a pictorial representation of corrosion resistance as per ASTM B 117 at 250 hrs by using the stoving system in accordance with the present disclosure;
Figure 7 shows a pictorial representation of corrosion resistance as per ASTM B 117 at 500 hrs by using the stoving system in accordance with the present disclosure;
Figure 8 shows a pictorial representation of corrosion resistance as per ASTM B 117 at 750 hrs by using the stoving system in accordance with the present disclosure;
Figure 9 shows a pictorial representation of corrosion resistance as per ASTM B 117 at 1000 hrs by using the stoving system in accordance with the present disclosure; and
Figure 10 shows a pictorial representation of corrosion resistance as per ASTM B 117 post tape test at 1000 hrs using the stoving system in accordance with the present disclosure.
DETAILED DESCRIPTION
Embodiments, of the present disclosure, will now be described with reference to the accompanying drawing.
Embodiments are provided so as to thoroughly and fully convey the scope of the present disclosure to the person skilled in the art. Numerous details are set forth, relating to specific components, and methods, to provide a complete understanding of embodiments of the present disclosure. It will be apparent to the person skilled in the art that the details provided in the embodiments should not be construed to limit the scope of the present disclosure. In some embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.
The terminology used, in the present disclosure, is only for the purpose of explaining a particular embodiment and such terminology shall not be considered to limit the scope of the present disclosure. As used in the present disclosure, the forms "a,” "an," and "the" may be intended to include the plural forms as well, unless the context clearly suggests otherwise. The terms "comprises," "comprising," “including,” and “having,” are open-ended transitional phrases and therefore specify the presence of stated features, integers, steps, operations, elements, modules, units and/or components, but do not forbid the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The particular order of steps disclosed in the method and process of the present disclosure is not to be construed as necessarily requiring their performance as described or illustrated. It is also to be understood that additional or alternative steps may be employed.
Conventionally used compositions for reducing corrosion are majorly based on film-forming polymeric organic polymers, a mixture of pigments and extender solids, at least one of which is effective in retarding corrosion of the substrate metal. Pigments containing lead, the particular red lead, and hexavalent chromium, for instance, zinc potassium chromate, are efficient anti-corrosive pigments and have been widely used with success. However, due to the highly toxic nature of lead and hexavalent chromium, their use is restricted and hence they are replaced with alternative materials. However, such alternative material does not have a performance matching that of lead and hexavalent chromium. Further, zinc phosphate is considered non-toxic and is extensively used as an anti-corrosive pigment. However, deficiencies in the performance of zinc phosphate are widely reported, in particular its inability to prevent rust creep from damages in the coating. Although slightly soluble metal salts of organic acids are extensively used as corrosion inhibiting additives in aqueous reservoir systems, surprisingly these materials are not widely used as corrosion inhibiting pigments in the surface coating compositions. Still, further, the use of barium salts of hydroxy carboxylic acid such as salicylic acid (barium salicylic) has also been reported. However, barium salicylate is soluble in water at a level greater than 10% w/w, and hence it is liable from a coating containing barium salicylate.
The present disclosure relates to a silicone grafted cardanol modified epoxy urethane resin and a coating composition obtained therefrom. Particularly, the present disclosure relates to an anti-corrosive coating composition comprising a silicone grafted cardanol modified epoxy urethane resin. Further, the present disclosure also relates to a process of preparing the silicone grafted cardanol modified epoxy urethane resin.
In an aspect, the silicone grafted cardanol modified epoxy urethane resin comprises a reaction product of cardanol modified epoxy resin having epoxide equivalent weight 3000-5000, a polyisocyanate, and a silicone resin. The silicone grafted cardanol modified epoxy urethane resin is characterized by a clear solution having an average molecular weight in the range of 20000 to 60000 g/mole.

In an embodiment of the present disclosure, the silicone grafted cardanol modified epoxy urethane is obtained by reacting an epoxy resin (diglycidyl ether of bisphenol A) in an amount in the range of 20-50 mass% with respect to the total mass of the resin, a cardanol in an amount in the range of 8-30 mass% with respect to the total mass of the resin, a catalyst in an amount in the range of 0.001-0.05 mass% with respect to the total mass of the resin, xylene in an amount in the range of 15-25 mass% with respect to the total mass of the resin, a polyisocyanate in an amount in the range of 5 mass% with respect to the total mass of the resin, isobutanol in an amount in the range of 0.2 -1 mass% with respect to the total mass of the resin, and a silicone resin in an amount in the range of 1-7 mass% with respect to the total mass of the resin in a solvent medium.

In an embodiment of the present disclosure, the silicone grafted cardanol modified epoxy urethane is further diluted with xylene, methoxy propyl acetate and/or cyclohexanone providing a viscosity of W-Z 2 at 25°C on Gardner scale.

In an embodiment of the present disclosure, the catalyst is at least one selected from the group consisting of triethanolamine, triphenylphosphine, metal oxides, secondary amines, tertiary amines, sodium hydroxide, potassium hydroxide and 2-methyl imidazole. In an exemplary embodiment of the present disclosure, the catalyst is triethanolamine. In another exemplary embodiment of the present disclosure, the catalyst is triphenylphosphine.
In an embodiment of the present disclosure, the polyisocyanate is at least one selected from the group consisting of aliphatic polyisocyanate, aromatic polyisocyanate and cycloaliphatic polyisocyanate or their prepolymers
In an embodiment of the present disclosure, the polyisocyanate is selected from the group consisting of diphenylmethane diisocyanate, toluene di-isocyanate, isophorone diisocyanate, and hexamethylene diisocyanate. In an exemplary embodiment of the present disclosure, the polyisocyanate is diphenylmethane diisocyanate. In yet another exemplary embodiment of the present disclosure, the polyisocyanate s is toluene diisocyanate.
In an embodiment of the present disclosure, the silicone resin is selected from silanol functional silicone resin and silanol functional phenyl-propyl polysiloxane. In an exemplary embodiment of the present disclosure, the silicone resin is silanol-functional silicone resin.
In another aspect, the present disclosure relates to a process for preparing the silicone grafted cardanol modified epoxy urethane resin.
The process is described in detail.
In a first step, predetermined amounts of an epoxy resin and cardanol are reacted in the presence of a catalyst at a first predetermined temperature for a first predetermined time period to obtain a reaction mixture.

In an embodiment of the present disclosure, the epoxy resin is diglycidyl ether of bisphenol A.

In an embodiment of the present disclosure, the epoxy resin has an epoxide equivalent weight (EEW) in the range of 185 to 1050. In an exemplary embodiment of the present disclosure, the epoxy resin has an epoxide equivalent weight (EEW) of 425 to 550.

In an embodiment of the present disclosure, the catalyst is at least one selected from the group consisting of triethanolamine, triphenylphosphine, metal oxides, secondary amines, tertiary amines, sodium hydroxide, potassium hydroxide and 2-methyl imidazole. In an exemplary embodiment of the present disclosure, the catalyst is triethanolamine. In another exemplary embodiment of the present disclosure, the catalyst is triphenylphosphine.

In an embodiment of the present disclosure, the first predetermined temperature is in the range of 50°C to 100°C. In an exemplary embodiment of the present disclosure, the first predetermined temperature is 80°C.

In an embodiment of the present disclosure, the first predetermined time period is in the range of 5 to 10 hours. In an exemplary embodiment of the present disclosure, the first predetermined time period is 8 hours. In another exemplary embodiment of the present disclosure, the first predetermined time period is 7 hours. In yet another exemplary embodiment of the present disclosure, the first time period is 6 hours.

In an embodiment of the present disclosure, the epoxy resin is present in a fluid medium. In an exemplary embodiment of the present disclosure, the fluid medium is xylene.

In a second step, the temperature of the reaction mixture is raised in the range of 175 °C to 225°C to obtain a reaction mass.

In an embodiment of the present disclosure, in the second step, the fluid medium i.e. xylene is completely removed and recycled for re-use by raising and maintaining the temperature of the reaction mixture to obtain a reaction mass.

In an exemplary embodiment, the reaction temperature of the reaction mass is increased to 200°C till the complete removal of the fluid medium from the epoxy resin to obtain a reaction mass.

In an embodiment of the present disclosure, the fluid medium is xylene.

In a third step, the temperature of the reaction mass is raised in the range of 210°C to 250°C and maintained the temperature till a viscosity of R-W at 25°C on the Gardner scale is achieved to obtain a resultant mass.

In an exemplary embodiment of the present disclosure, the temperature of the reaction mass is raised to 225°C followed by maintaining the reaction temperature of the reaction mass till viscosity of R-W at 25°C on the Gardner scale at 25°C is achieved to obtain a resultant mass.

In an embodiment, the recovered xylene is recycled back for re-use in the same reaction step once the viscosity of R-W at 25°C on the Gardner scale is achieved.

In a fourth step, the resultant mass is cooled at a temperature in the range of 125°C to 200°C followed by diluting with a predetermined amount of a first fluid medium to obtain a cardanol modified epoxy resin. In an exemplary embodiment of the present disclosure, the resultant mass is cooled to 180°C. In another exemplary embodiment of the present disclosure, the resultant mass is cooled to 160°C. In yet another exemplary embodiment of the present disclosure, the resultant mass is cooled to 150°C.

In an embodiment of the present disclosure, the first fluid medium is at least one selected from the group consisting of mix-xylene, cyclohexanone and methoxy propyl acetate.

In an exemplary embodiment of the present disclosure, the first fluid medium is mix-xylene. In another exemplary embodiment of the present disclosure, the first fluid medium is mix-xylene and methoxy propyl acetate. In still another exemplary embodiment of the present disclosure, the first fluid medium is mix-xylene, methoxy propyl acetate and cyclohexanone.

In a fifth step, the cardanol modified epoxy resin is reacted with a polyisocyanate at a second predetermined temperature for a second predetermined time period to achieve a constant viscosity at 25oC to obtain a cardanol modified epoxy urethane resin.

In an embodiment of the present disclosure, the polyisocyanate is at least one selected from the group consisting of aliphatic, aromatic and cycloaliphatic polyisocyanate or their prepolymers. In an embodiment, the polyisocyanate is selected from the group consisting of diphenylmethane diisocyanate, toluene di-isocyanate, isophorone diisocyanate, and hexamethylene diisocyanate. In an exemplary embodiment of the present disclosure, the polyisocyanate is diphenylmethane diisocyanate. In yet another exemplary embodiment of the present disclosure, the polyisocyanate s is toluene diisocyanate.

In an embodiment of the present disclosure, the second predetermined temperature is in the range of 95°C to 110 °C. In an exemplary embodiment of the present disclosure, the second predetermined temperature is 105 oC.

In an embodiment of the present disclosure, the second predetermined time period is in the range of 5 to 10 hours. In an exemplary embodiment of the present disclosure, the second predetermined time period is 8 hours. In another exemplary embodiment of the present disclosure, the second predetermined time period is 7 hours. In yet another exemplary embodiment of the present disclosure, the second predetermined time period is 9 hours.

In an embodiment of the present disclosure, once the reaction is complete, traces of free isocyanate is quenched in n-butanol.

In a sixth step, the cardanol modified epoxy urethane resin is reacted with a silicone resin in the first fluid medium at a third predetermined temperature for a third predetermined time period till the reaction mass becomes transparent and the desired viscosity at 25°C is achieved to obtain the silicon grafted cardanol modified epoxy urethane resin.

In an embodiment of the present disclosure, the silicone resin is selected from silanol-functional silicone resin and silanol functional phenyl-propyl polysiloxane. In an exemplary embodiment of the present disclosure, the silicone resin is silanol-functional silicone resin.

In an embodiment of the present disclosure, the third predetermined temperature is in the range of 140°C to 155°C. In an exemplary embodiment of the present disclosure, the third predetermined temperature is 145 oC.

In an embodiment of the present disclosure, the third predetermined time period is in the range of 5 to 10 hours. In an exemplary embodiment of the present disclosure, the third predetermined time period is 6 hours. In another exemplary embodiment of the present disclosure, the third predetermined time period is 7 hours.

In an embodiment of the present disclosure, the first fluid medium is at least one selected from the group consisting of mix-xylene, cyclohexanone and methoxy propyl acetate. In an exemplary embodiment of the present disclosure, the first fluid medium is mix-xylene. In another exemplary embodiment of the present disclosure, the first fluid medium is mix-xylene and methoxy propyl acetate. In still another exemplary embodiment of the present disclosure, the first fluid medium is mix-xylene, methoxy propyl acetate, and cyclohexanone.

In an embodiment of the present disclosure, the silicone grafted cardanol modified epoxy urethane resin is characterized by having a clear solution having an average molecular weight in the range of 20000 to 60000 g/mole as measured by gel permeation chromatography.

In an exemplary embodiment of the present disclosure, the silicone grafted cardanol modified epoxy urethane resin is characterized by a clear resin solution having an average molecular weight of 20896 g/mole. In another exemplary embodiment of the present disclosure, the silicone grafted cardanol modified epoxy urethane resin is characterized by a clear solution having an average molecular weight of 22685 g/mole. In yet another exemplary embodiment of the present disclosure, the silicone grafted cardanol modified epoxy urethane resin is characterized by a clear solution having an average molecular weight of 21171 g/mole. In still another exemplary embodiment of the present disclosure, the silicone grafted cardanol modified epoxy urethane resin is characterized by a clear solution having an average molecular weight of 28368 g/mole.

In still another aspect, the present disclosure relates to an anti-corrosive composition.
The anti-corrosive composition comprises a binder in an amount in the range of 40 to 45 mass% with respect to the total mass of the composition, an anti-corrosive pigment in an amount in the range of 5 to 7 mass% with respect to the total mass of the composition, a pigment in an amount in the range of 5 to 7 mass% with respect to the total mass of the composition, an extender in an amount in the range of 18 to 25 mass% with respect to the total mass of the composition, a crosslinker in an amount in the range of 5 to 10 mass% with respect to the total mass of the composition, a dispersing agent in an amount in the range of 0.5 to 1 mass% with respect to the total mass of the composition, and a solvent in an amount in the range of 25 to 27 mass% with respect to the total mass of the composition.

In an embodiment of the present disclosure, the binder is a silicone grafted cardanol modified epoxy urethane resin. The silicone grafted cardanol modified epoxy urethane resin is characterized by having a clear solution having an average molecular weight in the range of 20000 to 60000 g/mole.

In an embodiment of the present disclosure, the anti-corrosive pigment is at least one selected from the group consisting of zinc phosphate, strontium and zinc phosphosilicates and zinc calcium strontium aluminium orthophosphate silicate hydrate. In an exemplary embodiment, the anti-corrosive pigment is a combination of zinc phosphate, strontium and zinc phosphosilicates and zinc calcium strontium aluminum orthophosphate silicate hydrate.

In an embodiment of the present disclosure, the pigment is at least one selected from the group consisting of titanium dioxide, carbon black and yellow iron oxide. In an exemplary embodiment, the pigment is a combination of titanium dioxide, carbon black and yellow iron oxide.

In an embodiment of the present disclosure, the extender is at least one selected from the group consisting of mica, talc, calcium carbonate and barium sulphate. In an exemplary embodiment of the present disclosure, the extender is a combination of mica, talc, calcium carbonate and barium sulphate.

In an embodiment of the present disclosure, the extender has a particle size in the range of 2 microns to 65 microns.

In an embodiment of the present disclosure, the particle size of mica is 65 microns, the particle size of talc is 10 microns, the particle size of calcium carbonate is 10 microns and the particle size of barium sulphate is 2 microns.

In an embodiment of the present disclosure, the crosslinker is an amino resins selected from the group consisting of alkylated melamine-formaldehyde resin, urea-formaldehyde resin and benzoguanamine resin. In an exemplary embodiment of the present disclosure, the crosslinker is alkylated melamine-formaldehyde.

In an embodiment of the present disclosure, the dispersing agent is a modified polyurethane solution.

In an embodiment of the present disclosure, the solvent is at least one selected from the group consisting of the mix- xylene, methoxy propyl acetate and cyclohexanone. In an exemplary embodiment of the present disclosure, the solvent is mix-xylene. In another exemplary embodiment of the present disclosure, the fluid medium is mix-xylene and methoxy propyl acetate. In still another exemplary embodiment of the present disclosure, the fluid medium is mix-xylene, methoxy propyl acetate, and cyclohexanone.
The anti-corrosive composition of the present disclosure is used for coating on steel/other metallic substrates requiring corrosion protection for applications such as industrial original equipment (OE) and domestic market / retail segment products (good anti-corrosive performance).
The foregoing description of the embodiments has been provided for purposes of illustration and is not intended to limit the scope of the present disclosure. Individual components of a particular embodiment are generally not limited to that particular embodiment, but, are interchangeable. Such variations are not to be regarded as a departure from the present disclosure, and all such modifications are considered to be within the scope of the present disclosure.
The present disclosure is further described in light of the following experiments which are set forth for illustration purpose only and not to be construed for limiting the scope of the disclosure. The following experiments can be scaled up to industrial/commercial scale and the results obtained can be extrapolated to industrial scale.
EXPERIMENTAL DETAILS
EXPERIMENT 1:
Example 1: Process for preparing the silicon grafted cardanol modified epoxy urethane resin (SCMEU-1) in accordance with the present disclosure
516.1 g of diglycidyl ether of bisphenol A (75% in xylene) having EEW 425-550 and 191.6 g of cardanol were charged under stirring and nitrogen sparging into a four necked flask fitted with a heating mantle, Dean & stark assembly, stirrer and nitrogen sparger and reacted in the presence of 0.2g of triethanolamine (25% solution in 2-octanol) at 80oC to obtain a reaction mixture. The temperature of the reaction mixture was slowly increased to 200 °C to obtain a reaction mass and xylene present in diglycidyl ether of bisphenol A (75% in xylene) was completely removed and recycled at the end of the reaction.
The temperature of the reaction mass was further increased to 225°C and maintained till the viscosity @ 60% in xylene at 25oC on a Gardner scale of T-V was achieved. Once the viscosity was achieved, the reaction mass was cooled down to 180°C and diluted with 242g of mix xylene (fresh xylene and recovered xylene) to obtain a cardanol modified epoxy resin @ 60% solids in xylene. The cardanol modified epoxy resin was synthesized in 7 hours.
The so obtained cardanol modified epoxy resin was reacted with 30.7 g of diphenyl methane di-isocyanate at 105oC for 9 hours till constant viscosity at 25°C on the Gardner Scale of Z5 was attained to obtain a cardanol modified epoxy urethane resin. Once constant viscosity was achieved, traces of free isocyanate were quenched in n-butanol.
792.3 g of the cardanol modified epoxy urethane resin was reacted with 23.8 g of silanol functional silicone resin at 145oC for 6 hours till the reaction mass became transparent and viscosity of Z2 at 25oC on the Gardner scale to obtain the silicon grafted cardanol modified epoxy urethane resin (SCMEU-1 having an average molecular weight by Gel permeation Chromatography of 20896 g/mole).
The so obtained silicon grafted cardanol modified epoxy urethane resin (SCMEU-1) was cooled and packed for further analysis and further was used in the composition of thin-film corrosion-resistant coatings.
Example 2: Process of preparing the silicon grafted cardanol modified epoxy urethane resin (SCMEU-2) in accordance with the present disclosure
Example 2 was prepared in a similar way as mentioned in example 1, except for the use of solvent. 896.8 g of cardanol modified epoxy urethane resin was reacted with 14.6 g of silanol functional silicone resin at 145oC with 44.3 g of mix-xylene and 44.3g of methoxy propyl acetate for 6 hours till the reaction mass became transparent and at 52% NVM viscosity of Z2 at 25oC on Gardner scale to obtain the silicon grafted cardanol modified epoxy urethane resin (SCMEU-2 having an average molecular weight by Gel permeation Chromatography of 22685 g/mole).
The so obtained silicon grafted cardanol modified epoxy urethane resin (SCMEU-2) was cooled and packed for further analysis and was further used in the composition of thin-film corrosion-resistant coatings.
Example 3: Process of preparing the cardanol modified epoxy urethane resin (CMEU) in accordance with the present disclosure
516.1 g of diglycidyl ether of bisphenol A (75% in xylene) having EEW 425-550 and 191.6 g of cardanol were charged under stirring and nitrogen sparging, into a four necked flask fitted with a heating mantle, Dean & stark assembly, stirrer and nitrogen sparger and reacted in the presence of 0.2g of triethanolamine (25% solution in 2-octanol) at 80°C to obtain a reaction mixture. The temperature of the reaction mixture was slowly increased to 200 °C to obtain a reaction mass and xylene present in diglycidyl ether of bisphenol A (75% in xylene) was completely removed and recycled at the end of the reaction.
The temperature of the reaction of mass was further increased to 225°C and maintained till the viscosity @ 60% in xylene at 25oC on a Gardner scale of T-V was achieved. Once viscosity was achieved, the reaction mass was cooled down to 160°C and diluted with 242 g of mix xylene (fresh xylene and recovered xylene) to obtain a cardanol modified epoxy resin @ 60% solids in xylene. The cardanol modified epoxy resin was synthesized in 8 hours.
The so obtained cardanol modified epoxy resin was reacted with 30.7g of diphenyl methane diisocyanate at 105oC for 9 hours till constant viscosity at 25oC of Z7 on the Gardner Scale to obtain a cardanol modified epoxy urethane resin.
Since the CMEU resin so obtained was having high viscosity, Stage 2 of siliconization resulted in premature gelation.
Example 4: Process for preparing the silicon grafted cardanol modified epoxy urethane resin (SCMEU-4) in accordance with the present disclosure
516.1 g of diglycidyl ether of bisphenol A (75% in xylene) having EEW 425-550 and 191.6 g of cardanol were charged under stirring and nitrogen sparging into a four necked flask fitted with a heating mantle, Dean & stark assembly, stirrer and nitrogen sparger in the presence of 0.2 g of triethanolamine (25% solution in 2-octanol) at 80°C to obtain a reaction mixture. The temperature of the reaction mixture was slowly increased to 200°C to obtain a reaction mass and xylene present in diglycidyl ether of bisphenol A (75% in xylene) was completely removed and recycled at the end of the reaction.
The temperature of the reaction mass was further increased to 225°C and maintained till the viscosity @ 60% in xylene at 25oC on a Gardner scale of R-S was achieved. Once viscosity was achieved, the reaction mass was cooled down to 160°C and diluted with 323 g of mix xylene (fresh xylene and recovered xylene) and 49 g of cyclohexanone to obtain a cardanol modified epoxy resin @ 60% solids. The cardanol modified epoxy resin was synthesized in 7 hours.
The so obtained cardanol modified epoxy resin was reacted with 30.7g of diphenyl methane diisocyanate at 105°C for 7 hours till constant viscosity of Z3 at 25oC on the Gardner Scale was achieved to obtain a cardanol modified epoxy urethane resin. Once constant viscosity was achieved, traces of free isocyanate were quenched in n-Butanol.
793.6g of the cardanol modified epoxy urethane resin prepared above was reacted with 23.8g of silanol functional silicone resin at 145°C for 6 hours in a mixture of 146.1 g of mix-xylene and 36.5 g of cyclohexanone till the reaction mass became transparent and viscosity Y at 25oC on Gardner scale was achieved to obtain the silicon grafted cardanol modified epoxy urethane resin (SCMEU-4).
The so obtained silicon grafted cardanol modified epoxy urethane resin (SCMEU-4) was cooled and packed for further analysis and further used in thin-film corrosion-resistant coatings.
Example 5: Process for preparing the silicon grafted cardanol modified epoxy urethane resin (SCMEU-5) in accordance with the present disclosure
516.1 g of diglycidyl ether of bisphenol A (75% in xylene) having EEW 425-550 and 191.6 g of cardanol were charged under stirring and nitrogen sparging into a four necked flask fitted with a heating mantle, Dean & stark assembly, stirrer and nitrogen sparger and reacted in the presence of 0.2 g of triethanolamine (25% solution in 2-octanol) at 80°C to obtain a reaction mixture. The temperature of the reaction mixture was slowly increased to 200 °C to obtain a reaction mass and xylene present in diglycidyl ether of bisphenol A (75% in xylene) was completely removed and recycled at the end of the reaction.
The temperature of the reaction mass was further increased to 225°C and maintained till the viscosity @ 60% in xylene at 25oC on a Gardner scale U-V was achieved. Once the viscosity of R-W at 25°C on the Gardner scale was achieved, the reaction mass was cooled down to 150°C and diluted with a mixture of 323g of mix xylene and 48.5 g of cyclohexanone to obtain a cardanol modified epoxy resin. The cardanol modified epoxy resin was synthesized in 8 hours.
The so obtained cardanol modified epoxy resin was reacted with 28g of diphenyl methane diisocyanate at 105 oC for 7 hours till constant viscosity Z3 at 25°C on the Gardner Scale was achieved to obtain a cardanol modified epoxy urethane resin. Once constant viscosity was achieved, traces of free isocyanate were quenched in n-Butanol.
787.1 g of the cardanol modified epoxy urethane resin was reacted with 23.8 g of silanol functional silicone resin at 145°C in a mixture of 151.3 g of mix-xylene and 37.8 g of cyclohexanone for 6 hours till the reaction mass became transparent and viscosity Z1-Z2 at 25oC on Gardner scale was achieved to obtain the silicon grafted cardanol modified epoxy urethane resin (SCMEU-5 having an average molecular weight by Gel permeation Chromatography of 21171 g/mole).
The so obtained silicon grafted cardanol modified epoxy urethane resin (SCMEU-5) was cooled and packed for further analysis and further used in thin-film corrosion-resistant coatings.
Example 6: Process for preparing the silicon grafted cardanol modified epoxy urethane resin (SCMEU-6) in accordance with the present disclosure
516.1g diglycidyl ether of bisphenol A (75% in xylene) having EEW 425-550 and 191.6 g of cardanol were charged under stirring and nitrogen sparging into a four necked flask fitted with heating mantle, Dean & stark assembly, stirrer and nitrogen sparger and reacted in the presence of 0.2 g of triethanolamine (25% solution in 2-octanol) at 80°C to obtain a reaction mixture. The temperature of the reaction mixture was slowly increased to 200 °C to obtain a reaction mass and xylene present in diglycidyl ether of bisphenol A (75% in xylene) was completely removed and recycled at the end of the reaction.
The temperature of the reaction mass was further increased to 220oC and maintained till the viscosity @ 60% in xylene at 25oC on a Gardner scale from V-W was achieved. Once viscosity was achieved, the reaction mass was cooled down to 150oC and was diluted with 371.3 g of mix xylene to obtain a cardanol modified epoxy resin. The cardanol modified epoxy resin was synthesized in 6 hours.
The so obtained cardanol modified epoxy resin was reacted with 30.7g of Diphenyl methane Di-isocyanate at 105oC for 9 hours till constant viscosity Z6 at 25oC on Gardner Scale was achieved to obtain a cardanol modified epoxy urethane resin. Once constant viscosity was achieved, traces of free isocyanate were quenched in n-Butanol.
795g of the cardanol modified epoxy urethane resin was reacted with 23.8 g of silanol functional silicone resin at 145oC in a mixture of 90.6g of mix-xylene and 90.6g of methoxy propyl acetate for 7 hours till the reaction mass became transparent and viscosity Z at 25oC on Gardner scale was achieved to obtain the silicon grafted cardanol modified epoxy urethane resin (SCMEU-6 having an average molecular weight by Gel permeation Chromatography of 28368 g/mole).
The so obtained silicon grafted cardanol modified epoxy urethane resin (SCMEU-6) was cooled and packed for further analysis and was further used in thin-film corrosion-resistant coatings.
Example 7: Process for preparing the silicon grafted cardanol modified epoxy urethane resin (SCMEU-7) in accordance with the present disclosure
The cardanol modified epoxy urethane resin was prepared in a similar way as mentioned in example 6, except 795g of the cardanol modified epoxy urethane resin was reacted with 23.8 g of silanol functional silicone resin at 145oC in a mixture of 72.5 g of mix-xylene, 36.2 g of cyclohexanone and 72.5 g of methoxy propyl acetate for 6 hours till the reaction mass became transparent and viscosity Z-Z1 at 25°C on Gardner scale was achieved to obtain the silicon grafted cardanol modified epoxy urethane resin (SCMEU-7 having an average molecular weight by Gel permeation Chromatography of 56376 g/mole).
The so obtained silicon grafted cardanol modified epoxy urethane resin (SCMEU-7) was cooled and packed for further analysis and used in thin-film corrosion-resistant coatings.
Example 8: Process for preparing the silicon grafted cardanol modified epoxy urethane resin (SCMEU-8) in accordance with the present disclosure
521.8 g of diglycidyl ether of bisphenol A (75% in xylene) having EEW 425-550 and 193.8 g of cardanol were charged under stirring and nitrogen sparging into a four necked flask fitted with a heating mantle, Dean & stark assembly, stirrer and nitrogen sparger and reacted in the presence of 0.1 g of triphenyl phosphine at 80 oC to obtain a reaction mixture. The temperature of the reaction mixture was slowly increased to 200°C to obtain a reaction mass and xylene present in diglycidyl ether of bisphenol A (75% in xylene) was completely removed and recycled at the end of the reaction.
The temperature of the reaction mass was further increased to 220°C and maintained till the viscosity @ 60% in xylene at 25oC on a Gardner scale of T-V was achieved. Once viscosity was achieved, the reaction mass was cooled to 150oC and was diluted with 375.5g of mix xylene (fresh xylene and recovered xylene) to obtain a cardanol modified epoxy resin. The cardanol modified epoxy resin was synthesized in 6 hours.
The so obtained cardanol modified epoxy resin was reacted with 20g of Toluene di-isocyanate at 105 oC for 8 hours till constant viscosity of Z3-Z4 at 25oC on the Gardner Scale to obtain a cardanol modified epoxy urethane resin. Once constant viscosity was achieved, traces of free isocyanate were reacted with n-butanol.
890g of the cardanol modified epoxy urethane resin was reacted with 14.6 g of silanol functional silicone resin at 145oC in 176.4 g of mix-xylene for 6 hours till the reaction mass became transparent and viscosity Z at 25oC on the Gardner scale was achieved to obtain the silicon grafted cardanol modified epoxy urethane resin (SCMEU-8).
The so obtained silicon grafted cardanol modified epoxy urethane resin (SCMEU-8) was cooled and packed for further analysis and was further used in thin film corrosion-resistant coatings.
Example 9: Process for preparing the silicon grafted cardanol modified epoxy urethane resin (SCMEU-9) in accordance with the present disclosure
The cardanol modified epoxy urethane resin was prepared in a similar way as mentioned in example 8.
793.6g of the cardanol modified epoxy urethane resin was reacted with 23.8 g of silanol functional silicone resin at 145 oC in 182.6 g of mix-xylene for 6 hours till the reaction mass became transparent and viscosity Y at 25oC on Gardner scale to obtain the silicon grafted cardanol modified epoxy urethane resin (SCMEU-9).
The so obtained silicon grafted cardanol modified epoxy urethane resin (SCMEU-9) was cooled and packed for further analysis and was further used in thin film corrosion-resistant coatings.
Example 10: Process for preparing the silicon grafted cardanol modified epoxy urethane resin (SCMEU-10) in accordance with the present disclosure
The cardanol modified epoxy urethane resin was prepared in a similar way as mentioned in example 9.
778.8 g of the cardanol modified epoxy urethane resin was reacted with 23.8 g of silanol functional silicone resin at 145oC in 32.7g of mix-xylene for 7 hours to obtain silicon grafted cardanol modified epoxy urethane resin (SCMEU-10). The silicon grafted cardanol modified epoxy urethane resin (SCMEU-10) obtained above was not found suitable as it showed a milky appearance on the glass plate showing an incomplete reaction. Therefore, higher silicone grafting i.e. 7% on resin solids was not taken forward for use in coatings.
EXPERIMENT 2:
Evaluation of the silicon grafted cardanol modified epoxy urethane resin prepared in accordance with the present disclosure on the paint performances
Process Details: The paint batches were processed in a lab-scale sand mill. The paint was adjusted to a consistency of 100 to 110 sec at 30°C on a Ford cup B4 viscometer. The paint samples were applied on pretreated MS (mild steel) cold roll steel (CRS) panels at a dry film thickness of 25 to 30 microns by using a suitable thinner spray application. The Stoving system was baked at 140°C/30 min and testing was carried out after 24 hrs of panel baking. In case of Air-drying system, the panels were air-dried for 7 days.
Example 1: A series of experiments were carried out by using different ratios of the extender to anticorrosive pigment combinations and also by using the silicon grafted cardanol modified epoxy urethane resin - SCMEU-08 as prepared above in example 8 of experiment 1.
Parameters studied:
- Role of different crosslinkers.
- Role of different anti-corrosive pigment
- Role of different extender combinations.
- Resin Ref. : SCMEU-08 i.e. as prepared in example 8 of experiment 1
All the batches were processed in the lab sand mill. The paint samples were baked at 140°C/30 min. The experiment panels were then tested for its salt spray test performance on pretreated MS (mild steel) panels at a dry film thickness (DFT) of 25 to 30 microns.
Table 1 shows the series of experiments by using different ratios of the extender to anticorrosive pigment combinations and by using the silicon grafted cardanol modified epoxy urethane resin - SCMEU-08 as prepared in example 8 of experiment 1.
Table 1:
Experiments (values in %)
Raw Material Function 1A 1B 2A 2B 3A 3B 4A 4B 5A 5B
SCMEU-08 Base Resin 43 41.5 43 41.5 43 41.5 43 41.5 48 46
alkylated melamine formaldehyde- Resimene 5901 Crosslinker 3.4 - 3.4 - 3.4 - 3.4 - 3.79 -
alkylated melamine Formaldehyde- Luwipal 018 Crosslinker - 7.57 - 7.57 - 7.57 - 7.57 - 8.39
Titanium Dioxide Pigment 4.18 4.18 4.18 4.18 4.18 4.18 4.18 4.18 4.18 4.18
Yellow Oxide Pigment 0.77 0.77 0.77 0.77 0.77 0.77 0.77 0.77 0.77 0.77
Black Pigment 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05
Strontium/Zinc Phosphosilicates (Halox SZP 391) Anticorrosive Pigment 5 5 5 5 - - - - - -
Zinc Phosphate Anticorrosive Pigment - - - - - - - - 7 7
Zinc Calcium Strontium Aluminium Orthophosphate Siica Hydrate (HEUCOPHOS ZCP-PLUS) Anticorrosive Pigment - - - - 5 5 5 5 - -
Natural Barium Sulphate (2 Microns) Extender 10 10 10.2 10.2 10 10 10.2 10.2 - -
Calcium Carbonate (10 Microns) Extender 15.2 15.2 10.2 10.2 15.2 15.2 10.2 10.2 - -
Mica 240 Mesh Extender - - - - - - - - 7 7
Talc - 500 Mesh Extender - - - - - - - - 11.5 11.5
Talc 10 Microns Extender - - 4.8 4.8 - - 4.8 4.8 - -
Polymeric Wetting/ Dispersing Agent (modified polyurethane solution) DISPERBYK 163) Dispersing Agent 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8
Mix Xylene Solvent 17.07 14.99 16.07 14.99 17.07 14.99 17.07 14.99 19.50 18.00
99.47 100.06 98.47 100.06 99.47 100.06 99.47 100.06 102.59 103.69
Viscosity at 30°C (sec) 96 95 97 98 99 97 103 98 96 98

Inference:
Table 2 shows the inference of experiments 1A to 5B.
Salt Spray Test Performance as per ASTM B 117 (After 750 hrs)
Substrate: MS (mild steel panels) (No Phosphate Treatment)
DFT (dry film thickness): 25 – 30 microns

Table 2:
Sr No Description
(experiments) Observations Remarks
1 1A Scattered rust spots throughout the panel. Panels are fully rusty. Dropped.
2 1B Isolated rust spots throughout the panel. Dropped.
3 2A Few rust spots on the panel. Shortlisted for further study based on the severity of rust.
4 2B Scattered big rust spots throughout the panel. No peel off seen in the tape test. Dropped.
5 3A Scattered rust spots on the panel. Panels are fully rusty. Dropped.
6 3B Isolated blisters throughout the panel. Isolated rust spots throughout the panel. Dropped.
7 4A Scattered blisters throughout the panel. Few rust spots on the panel. Peel off 12 mm on either side in tape test. Dropped.
8 4B Scattered blisters throughout the panel. Few rust spots on the panel. Shortlisted for further study based on the severity of rust.
9 5A Scattered blisters throughout the panel. Few rust spots on the panel. Peel off 12 mm on either side in tape test. Shortlisted for further study based on the severity of rust.
10 5B Isolated blisters throughout the panel. Few rust spots on the panel. Peel off 12 mm on either side in tape test. Shortlisted for further study based on the severity of rust.

Based on the above, the composition of experiments 2A, 4B, and 5B were shortlisted for further evaluation.
Example 2:
The pigment/extender combination as per experiments 2A, 4B, 5B were used for processing paint by using the silicon grafted cardanol modified epoxy urethane resin - SCMEU-02 i.e. prepared in example 2 of experiment 1.
The paint was studied under two 2 different curing systems:
(a) Stoving using amino resin crosslinker i.e. alkylated melamine-formaldehyde and
(b) Air drying using metal driers as a catalyst.
All the batches were processed on the lab-scale sandmill. The paint samples were baked at 140°C/30 min. for the stoving system. Airdrying system panels were air-dried at ambient conditions for 7 days. The experiment panels were then tested for its salt spray test performance on pretreated MS (mild steel) panels at a (dry film thickness) DFT of 25-30 microns.
Table 3 shows the various pigment/extender combinations as per experiments 2A, 4B, 5B were used for processing paint by using the resin lot - SCMEU-02 i.e. as prepared in example 2 of experiment 1.
Table 3:
Experiments (values in %)
Raw Material Function 6A
6B 7A
7B
8A
8B
8C

SCMEU-02 Base Resin 42.50 36.50 40.5 39.5 41.44 37.44 40.44
Yellow Oxide Pigment 0.77 0.77 0.77 0.77 0.77 0.77 0.77
Strontium/Zinc Phosphosilicates (Halox SZP 391) Anticorrosive Pigment 5 5 - - - - -
Zinc Calcium Strontium Aluminium Orthophosphate Siica Hydrate (HEUCOPHOS ZCP-PLUS) Anticorrosive Pigment - - 5 5 - - -
Black Pigment 0.05 0.05 0.05 0.05 0.05 0.05 0.05
Zinc Phosphate Anticorrosive Pigment - - - - 7 7 7
Titanium Dioxide Rutile Pigment 4.18 4.18 4.18 4.18 4.18 4.18 4.18
Natural Barium Sulphate (2 Microns) Extender 10.2 10.2 10.2 10.2 - - -
Mica 240 Mesh Extender - - - - 7 7 7
Talc 10 Microns Extender 4.8 4.8 4.8 4.8 11.50 11.50 11.50
Calcium Carbonate 10 Microns Extender 10.2 10.2 10.2 10.2 - - -
Manganese Octoate (5%) Metal Drier 0.04 - 0.04 - 0.04 - -
Mek Oxime Anti-skinning Agent 0.15 - 0.15 - 0.15 - -
Polymeric Wetting/ Dispersing Agent (modified polyurethane solution-DISPERBYK 163) Dispersing Agent 0.8 0.8 0.8 0.8 0.8 0.8 0.8
Mix Xylene Solvent 24.31 21 23.31 23.46 27.07 24.76 25.22
alkylated Melamine Formaldehyde Resimene 5901 Crosslinker - - - 3.04 - - 3.04
alkylated Melamine Formaldehyde Luwipal 018 Crosslinker - 6.5 - - - 6.5 -
103 100 100 102 100 100 100
Viscosity at 30°C (sec) on Ford cup B4 109 97 103 109 105 99 99
Finish on Hegman Gauge (HG) 5 5 5 5 5 5 5

Inference:
Table 4 shows the inference of experiments 6A to 8C.
Salt Spray Test Performance as per ASTM B 117 (After 1000 hrs)
Substrate: Phosphated MS Panels (Zinc Phosphate)
DFT: 25 – 30 microns
Table 4:
Sr No Description
(experiments) Observations Remarks
1 6A Blisters with rust spots at the non-scribe area. Avg Creepage = 2.5 mm. Max Creepage = 3 mm. Results inferior vis-a-vis SCMEU-01 set.
2 6B Film Integrity is ok. No blisters in the non-scribe area. Avg Creepage = 2mm. Max Creepage = 3 mm. Results inferior vis-a-vis SCMEU-01 set.
3 7A Blisters with rust spots at the non-scribe area. Avg Creepage = 2.5 mm. Max Creepage = 3 mm. Results inferior vis-a-vis SCMEU-01 set.
4 7B Film Integrity is ok. No blisters in the non-scribe area. Avg Creepage = 2mm. Max Creepage = 3 mm. Results inferior vis-a-vis SCMEU-01 set.
5 8A Fine blister spots throughout. Avg Creepage = 2 mm. Max Creepage = 2 mm. Results inferior vis-a-vis SCMEU-01 set.
6 8B Film Integrity is ok. No blisters in the non-scribe area. Avg Creepage = 2.5 mm. Max Creepage = 3 mm. Results inferior vis-a-vis SCMEU-01 set.
7 8C Film Integrity is ok. No blisters in the non-scribe area. Avg Creepage = 2mm. Max Creepage = 3 mm. Results inferior vis-a-vis SCMEU-01 set.

Example 3:
The pigment/extender combinations as per experiments 2A, 4B and 5B were used for processing paint using the silicon grafted cardanol modified epoxy urethane resin - SCMEU-01 i.e. as prepared in example 1 of experiment 1.
The paint was studied under two 2 different drying systems:
(a) Stoving using amino resin crosslinker i.e. alkylated melamine-formaldehyde and
(b) Air drying using metal driers as a catalyst
All the batches were processed on a lab-scale sandmill. The paint samples were baked at 140°C/30 min. for the stoving system. Airdrying system panels were air-dried at ambient conditions for 7 days. The experiment panels were then tested for its SST performance on pretreated MS panels at a DFT of 25-30 microns.
Table 5 shows the various pigment/extender combinations as per experiments 2A, 4B, 5B were used for processing paint using the silicon grafted cardanol modified epoxy urethane resin - SCMEU-01 i.e. as prepared in example 1 of experiment 1.
Table 5:
Raw Material Function 9A 9B 10A 10B 11A 11B 11C
SCMEU-01 Base Resin 42.5 36.5 40.5 39.5 41.44 37.44 40.44
Yellow Oxide Pigment 0.77 0.77 0.77 0.77 0.77 0.77 0.77
Strontium/Zinc Phosphosilicates (Halox SZP 391) Anticorrosive Pigment 5 5 - - - - -
Zinc Calcium Strontium Aluminium Orthophosphate Siica Hydrate (HEUCOPHOS ZCP-PLUS) Anticorrosive Pigment - - 5 5 - - -
Black Pigment 0.05 0.05 0.05 0.05 0.05 0.05 0.05
Zinc Phosphate Anticorrosive Pigment - - - - 7 7 7
Titanium Dioxide Rutile Pigment 4.18 4.18 4.18 4.18 4.18 4.18 4.18
Natural Barium Sulphate (2 Microns) Extender 10.2 10.2 10.2 10.2 - - -
Mica 240 Mesh Extender - - - - 7 7 7
Talc 10 Microns Extender 4.8 4.8 4.8 4.8 11.5 11.5 11.5
Calcium Carbonate 10 Microns Extender 10.2 10.2 10.2 10.2 - - -
Manganese Octoate (5%) Metal Drier 0.04 - 0.04 - 0.04 - -
Mek Oxime Antiskinning Agent 0.15 - 0.15 - 0.15 - -
Polymeric Wetting/Dispersing Agent (modified polyurethane solution- DISPERBYK 163) Dispersing Agent 0.8 0.8 0.8 0.8 0.8 0.8 0.8
Mix Xylene Solvent 24.31 21 23.31 23.46 27.07 24.76 25.22
alkylated Melamine Formaldehyde Resimene 5901 Crosslinker - - - 3.04 - - 3.04
alkylated Melamine Formaldehyde)- Luwipal 018 Crosslinker - 6.5 - - - 6.5 -
103 100 100 102 100 100 100
Viscosity at 30°C 109 97 103 109 105 99 99
Finish on Hegman Gauge (HG) 5 5 5 5 5 5 5

Inference:
Table 6 shows the inference of experiments 9A to 11C.
Salt Spray Test Performance as per ASTM B 117 (After 1000 hrs)
Substrate: Phosphated MS Panels (Zinc Phosphate)
FT: 25 – 30 microns (Observation every 250 hrs provided separately).

Table 6
Sr No Description
(experiments) Observations Remarks
1 9A Blisters with rust spots at the non-scribe area. Avg Creepage = 2.5 mm. Max Creepage = 3 mm. Results inferior to 11A & 11B panels.
2 9B Film Integrity is ok. No blisters in the non-scribe area. Avg Creepage = 2mm. Max Creepage = 3 mm. Results inferior to 11A & 11B panels.
3 10A Blisters with rust spots at the non-scribe area. Avg Creepage = 2.5 mm. Max Creepage = 3 mm. Results inferior to 11A & 11B panels.
4 10B Film Integrity is ok. No blisters in the non-scribe area. Avg Creepage = 2mm. Max Creepage = 3 mm. Results inferior to 11A & 11B panels.
5 11A Fine blister spots throughout. Avg Creepage = 2 mm. Max Creepage = 2 mm. Best performance upto 500 hrs
6 11B Film Integrity is ok. No blisters in the non-scribe area. Avg Creepage = 2.5 mm. Max Creepage = 3 mm. Best performance in the stoving system.
7 11C Film Integrity is ok. No blisters in the non-scribe area. Avg Creepage = 2mm. Max Creepage = 3 mm. Results inferior to 11A & 11B panels.

Paint samples processed using 5% silicon grafted cardanol modified epoxy urethane resin SCMEU-01 showed better anti-corrosive performance than 3% Silicone modification SCMEU-02.
Good corrosion performance was observed with experiment 11A (for Air-drying System) and experiment 11B (for Stoving system) which are using the silicon grafted cardanol modified epoxy urethane resin - SCMEU-01 as prepared in example 1 of experiment 1.
The results of the good corrosion performance are tabulated below in tables 7 and 8:
A) Liquid paint properties of the anticorrosive composition of the present disclosure
Table 7
Sr
no Properties Specification Observations
Air-Drying System Stoving System
1 Appearance on panel A smooth film without any film defect. Passes Passes
2 Viscosity on Fordcup B4 viscometer at 30°C 100 ± 10 sec 105 sec 99 sec
3 Weight Per Litre at 30°C 1.2 ± 0.05 1.19 1.2
4 % Non-volatile content, by weight (120°/1hr) 50 - 55 52.42 54.07
5 % Thinner intake by volume for getting 22 ± 2 sec. application viscosity at 30°C. 20 - 30% 25%
(New Thinner) 27%
(New Thinner)

B) Dry Film properties of the anticorrosive composition of the present disclosure
Table 8:
Panel Preparation: MS (mild steel) Panel ---> Zinc Phosphate Pretreatment ---> Apply Anticorrosive composition - (25 - 30µ) ---> flash off time 8 - 10 min.
Air-drying system: Properties tested after 7 days of air-drying.
STG System: Bake at 140°C/30 min. Properties tested after 24 hours of air-drying of baked panels.
Sr
No Properties Test Method Observations
Air-Drying System Stoving System

1 Appearance Visual Observation A smooth uniform film without any film defect. The smooth uniform film without any film defect.
2 Dry Film Thickness DFT Meter 25 - 30 µ 25 - 30 µ
3 Gloss at 60° Glossmeter 5 - 10 units 10 - 15 units
4 Crosscut Adhesion 1 mm gap, 5 x 5 pattern.
Permacel P 254 tape. Passes Passes
5 Corrosion Resistance
as per ASTM B 117 250 Hrs No Blisters.
Creepage < 1mm from scribe as depicted in figure 1 No Blisters.
Creepage < 1mm from scribe as depicted in figure 6
500 Hrs No Blisters.
Creepage < 1mm from scribe as depicted in figure 2 No Blisters.
Creepage < 1mm from scribe as depicted in figure 7
750 Hrs Fine blister spots were observed.
Creepage < 1mm from scribe as depicted in figure 3 No Blisters.
Creepage < 2mm from scribe as depicted in figure 8
1000 Hrs Fine blister spots were observed.
Creepage ~ 2mm from scribe as depicted in figure 4 No Blisters on non-scribe areas.
Blisters were seen on the scribe with creepage < 3mm from the scribe as depicted in figure 9
1000 Hrs
(Post Tape Test) Fine blister spots were observed.
Creepage ~ 2mm from the scribe. No paint peel off on the tape test as depicted in figure 5 No Blisters on non-scribe areas.
Blisters were seen on the scribe with creepage < 3mm from the scribe. Except for a few spot failure, no paint peel off on the tape test as depicted in figure 10.

TECHNICAL ADVANCEMENTS
The present disclosure described herein above has several technical advantages including, but not limited to, the realization of the silicone grafted cardanol-modified epoxy urethane resin;
• has an average molecular weight in the range of 20000 to 60000 g/mole.
a process of preparing the silicone grafted cardanol-modified epoxy urethane resin that
• utilizes a simple and two-stage process.
An anti-corrosive composition comprising silicone grafted cardanol-modified epoxy urethane resin, that
• provides exceptional corrosion resistance and is used in thin-film corrosion-resistant coatings;
• is applied in a single coat at a low thickness of 20 microns to 30 microns;
• is a 1 K system (single component system) with high corrosion resistance;
• is solvent borne single coat anti-corrosive primer at low Dry Film Thickness (DFT);
• is free of hazardous heavy metals such as Lead and Chromium and the like; and
• provides 1000 hrs of ASTM B117 salt spray resistance (when applied on pretreated mild steel at a dry film thickness of 25-30 micron in a single coat).
Throughout this specification, the word “comprise”, or variations such as “comprises” or “comprising, 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.
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 invention to achieve one or more of the desired objects or results. While certain embodiments of the inventions have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Variations or modifications to the formulation of this invention, within the scope of the invention, may occur to those skilled in the art upon reviewing the disclosure herein. Such variations or modifications are well within the spirit of this invention.
The numerical values given for various physical parameters, dimensions and quantities are only approximate values and it is envisaged that the values higher than the numerical value assigned to the physical parameters, dimensions and quantities fall within the scope of the invention unless there is a statement in the specification to the contrary.
While considerable emphasis has been placed herein on the specific features of the preferred embodiment, it will be appreciated that many additional features can be added and that many changes can be made in the preferred embodiment without departing from the principles of the disclosure. These and other changes in the preferred embodiment of the disclosure 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.

, Claims:WE CLAIM:
1. A silicone grafted cardanol modified epoxy urethane resin comprises a reaction product of
a. cardanol modified epoxy resin having epoxide equivalent weight 3000-5000;
b. polyisocyanate; and
c. silicone resin,
wherein said silicone grafted cardanol modified epoxy urethane resin is characterized by having an average molecular weight in the range of 20000 to 60000 g/mole.
2. The silicone grafted cardanol modified epoxy urethane as claimed in claim 1 is obtained by reacting following ingredients in a solvent medium :
• 20- 50 mass% epoxy resin (diglycidyl ether of bisphenol A);
• 8-30 mass % cardanol;
• 0.001-0.05 mass % catalyst;
• 15-25 mass % xylene;
• 5 mass % polyisocyanate;
• 0.2 -1 mass % isobutanol; and
• 1-7 mass % silicone resin.
3. The silicone grafted cardanol modified epoxy urethane as claimed in claims 1 and 2 is further diluted with xylene, methoxy propyl acetate and/or cyclohexanone providing a viscosity of W-Z 2 at 25°C on Gardner scale.
4. The silicone grafted cardanol modified epoxy urethane as claimed in claim 2, wherein said catalyst is at least one selected from the group consisting of triethanolamine, triphenylphosphine, metal oxides, secondary amines, tertiary amines, sodium hydroxide, potassium hydroxide and 2-methyl imidazole.
5. The silicone grafted cardanol modified epoxy urethane as claimed in claims 1 and 2, wherein said polyisocyanate is at least one selected from the group consisting of aliphatic polyisocyanate, aromatic polyisocyanate and cycloaliphatic polyisocyanate or their prepolymers
6. The silicone grafted cardanol modified epoxy urethane as claimed in claims 1 and 2 wherein said polyisocyanate is selected from the group consisting of diphenylmethane diisocyanate, toluene di-isocyanate, isophorone diisocyanate, and hexamethylene diisocyanate.
7. The silicone grafted cardanol modified epoxy urethane as claimed in claims 1 and 2, wherein said silicone resin is selected from silanol functional silicone resin and silanol functional phenyl-propyl polysiloxane.
8. A process for preparing a silicone grafted cardanol modified epoxy urethane resin, said process comprising the following steps:
a) reacting predetermined amounts of an epoxy resin and a cardanol in the presence of a catalyst at a first predetermined temperature for a first predetermined time period to obtain a reaction mixture;
b) raising a temperature of said reaction mixture in the range of 175°C to 225°C to obtain a reaction mass;
c) raising a temperature of said reaction mass in the range of 210°C to 250°C and maintaining said temperature to achieve a viscosity of R-W at 25°C on the Gardner scale, to obtain a resultant mass;
d) cooling said resultant mass at a temperature in the range of 125°C to 200°C followed by diluting it with a predetermined amount of a first fluid medium to obtain a cardanol modified epoxy resin;
e) reacting said cardanol modified epoxy resin with a polyisocyanate at a second predetermined temperature for a second predetermined time period to achieve a constant viscosity at 25oC to obtain a cardanol modified epoxy urethane resin; and
f) reacting said cardanol modified epoxy urethane resin with a silicone resin in said first fluid medium at a third predetermined temperature for a third predetermined time period till the reaction mass becomes transparent and the viscosity at 25°C is achieved to obtain said silicon grafted cardanol modified epoxy urethane resin.

9. The process as claimed in claim 8, wherein said epoxy resin is present in a fluid medium, wherein said fluid medium is xylene and wherein in step (b) said fluid medium is completely removed and recycled for re-use by raising and maintaining said temperature of the reaction mixture to obtain a reaction mass.

10. The process as claimed in claim 8, wherein said epoxy resin is diglycidyl ether of bisphenol A having an epoxide equivalent weight in the range of 185 to 1050.

11. The process as claimed in claim 8, wherein said first fluid medium is at least one selected from the group consisting of mix-xylene, cyclohexanone and methoxy propyl acetate.

12. The process as claimed in claim 8, wherein said catalyst is at least one selected from the group consisting of triethanolamine, triphenylphosphine, metal oxides, secondary amines, tertiary amines, sodium hydroxide, potassium hydroxide and 2-methyl imidazole.

13. The process as claimed in claim 8, wherein said polyisocyanate is at least one selected from the group consisting of aliphatic polyisocyanate, aromatic polyisocyanate and cycloaliphatic polyisocyanate or their prepolymers wherein said polyisocyanate is selected from the group consisting of diphenylmethane diisocyanate, toluene di-isocyanate, isophorone diisocyanate, and hexamethylene diisocyanate.

14. The process as claimed in claim 8, wherein said silicone resin is selected from silanol functional silicone resin and silanol functional phenyl-propyl polysiloxane.

15. The process as claimed in claim 8, wherein said first predetermined temperature is in the range of 50°C to 100°C; said second predetermined temperature is in the range of 95°C to 110 °C; and said third predetermined temperature is in the range of 140°C to 155°C.

16. The process as claimed in claim 8, wherein said first predetermined time period, said second predetermined time period and said third predetermined time period are independently selected in the range of 5 to 10 hours.

17. An anti-corrosive coating composition comprising:
a) a binder in an amount in the range of 40 to 45 mass% with respect to the total mass of the composition;
b) an anti-corrosive pigment in an amount in the range of 5 to 7 mass% with respect to the total mass of the composition;
c) a pigment in an amount in the range of 5 to 7 mass% with respect to the total mass of the composition;
d) an extender in an amount in the range of 18 to 25 mass% with respect to the total mass of the composition;
e) a crosslinker in an amount in the range of 5 to 10 mass% with respect to the total mass of the composition;
f) a dispersing agent in an amount in the range of 0.5 to 1 mass% with respect to the total mass of the composition; and
g) a solvent in an amount in the range of 25 to 27 mass% with respect to the total mass of the composition.

18. The anti-corrosive coating composition as claimed in claim 17, wherein said binder is a silicone grafted cardanol modified epoxy urethane resin.

19. The anti-corrosive coating composition as claimed in claim 17, wherein said anti-corrosive pigment is at least one selected from the group consisting of zinc phosphate, strontium zinc phosphosilicates and zinc calcium strontium aluminum orthophosphate silicate hydrate.

20. The anti-corrosive coating composition as claimed in claim 17, wherein said pigment is at least one selected from the group consisting of titanium dioxide, carbon black and yellow iron oxide.

21. The anti-corrosive coating composition as claimed in claim 17, wherein said extender is at least one selected from the group consisting of mica, talc, calcium carbonate and barium sulphate.

22. The anti-corrosive coating composition as claimed in claim 17, wherein said extender has a particle size in the range of 2 microns to 65 microns.

23. The anti-corrosive coating composition as claimed in claim 17, wherein said crosslinker is amino resins selected from the group consisting of alkylated melamine-formaldehyde resin, urea-formaldehyde resin and benzoguanamine resin.

24. The anti-corrosive coating composition as claimed in claim 17, wherein said dispersing agent is modified polyurethane solution.

25. The anti-corrosive coating composition as claimed in claim 17, wherein said fluid medium is at least one selected from the group consisting of mix xylene, xylene, n-butanol, methoxy propyl acetate and cyclohexanone.

Dated this 22nd day of July, 2022

_______________________________
MOHAN RAJKUMAR DEWAN, IN/PA – 25
of R.K.DEWAN & CO.
Authorized Agent of Applicant

TO,
THE CONTROLLER OF PATENTS
THE PATENT OFFICE, AT MUMBAI