DESC:Field of Invention
The present disclosure relates to an epoxy ester urethane resin, methods of preparing such resins and coating compositions comprising such resins.

Background
Epoxy esters are widely used in the preparation of adhesives, paints, and coatings as corrosion inhibitors. When applied to a metallic surface, epoxy esters harden to form a highly protective layer, which increases the durability of the metal.
Epoxy esters are generally prepared by reacting an epoxy resin (diglycidyl ether of bisphenol A) of suitable epoxide equivalent with mono or dicarboxylic acids of long carbon chains at an elevated temperature in excess of 200°C in the presence of catalysts. The preparation of the epoxy ester is completed once the desired acid value and viscosity are achieved, followed by dilution in either xylene or its combination with an oxygenated solvent.
CN103073701A discloses a fatty acid modified epoxy resin. The fatty acid modified epoxy resin is prepared by mixing a liquid difunctional epoxy resin and a fatty acid in the presence of a catalyst and a fatty acid flexible chain segment. The fatty acid modified epoxy resin introduces a chain flexible segment into the epoxy resin molecular chain that improves the toughness of the epoxy resin and the coating film.
US5124406 discloses an epoxy ester coating copolymer resin which is useful in the preparation of an air curable, high solids coating. The epoxy ester coating copolymer is the reaction product of a polymerizable base, an epoxy resin and a monobasic acid. The polymerizable base is a reaction product of (a) a fatty acid having free radical polymerizable double bonds in addition to (b) a vinyl monomer selected from the group consisting of styrene, alpha-methyl styrene, vinyl toluene and mixtures thereof.
Singh A.P, Gunasekaran. G et al titled “Fatty acid based waterborne air-drying epoxy ester resin for coating applications”, progress in organic coatings, 87(2015)95-105 discloses synthesis of water-soluble epoxy ester resin by partially reacting bis-phenol A based epoxy resin with different fatty acids. Further, the prepared epoxy esters were neutralized using phosphoric, lactic, acetic and hydrochloric acids to make them water soluble. It was observed that phosphoric acid neutralized tung oil fatty acid-based epoxy ester has better mechanical and anticorrosive properties than the rest of the water-soluble polymers.
Although various epoxy esters are known, there has been a constant requirement to achieve low-cost epoxy ester resins with improved corrosion resistance performance and mechanical properties, especially for direct to metal applications, high solubility in Mineral Turpentine Oil (MTO), quick drying, and high gloss.
Summary
An epoxy ester urethane resin is disclosed. Said epoxy ester urethane resin comprises cardanol modified epoxy ester urethane resin represented by Formula 1:

Formula 1
wherein:
n is 2-5;
R is C14-C18 fatty acid carbon chain; and
R` is O-Cardanol modified epoxy ester.
A process for preparing the aforesaid epoxy ester urethane resin is also disclosed. Said process comprises the steps of: reacting 10-35 wt.% of cardanol and 30-60 wt.% of a base epoxy resin having an epoxide equivalent weight of 300-975 to obtain a cardanol modified epoxy resin; reacting 40-70 wt.% of the cardanol modified epoxy resin with 15-30 wt.% of a C14-C18 fatty acid having an iodine value of 110-180 gm I2 /100gm and an acid value 195-205 mg KOH /gm to obtain a cardanol modified epoxy ester; and reacting 80-95 wt.% of the cardanol modified epoxy ester with 1-5 wt.% of a polyisocyanate to obtain the epoxy ester urethane resin.
Detailed Description
Reference will now be made in detail to embodiments of the present disclosure. The terminology used in the description presented herein is not intended to be interpreted in any limited or restrictive manner, simply because it is being utilized in conjunction with a detailed description of certain specific embodiments of the invention. Furthermore, embodiments of the invention may include several features, no single one of which is solely responsible for its desirable attributes, or which is essential to practicing the inventions herein described.
It will be understood by those skilled in the art that the foregoing general description and the following detailed description are explanatory of the invention and are not intended to be restrictive thereof.
The terms “a,” “an,”, and “the” are used to refer to “one or more” (i.e., to at least one) of the grammatical object of the article.
Reference throughout this specification to “an aspect”, “another aspect” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention.
The terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion and are not intended to be construed as “consists of only”, such that a process or method that comprises a list of steps does not include only those steps but may include other steps not expressly listed or inherent to such process or method.
Likewise, the terms “having” and “including”, and their grammatical variants are intended to be non-limiting, such that recitations of said items in a list are not to the exclusion of other items that can be substituted or added to the listed items.
Also, any numerical range recited herein is intended to include all sub-ranges subsumed therein. For example, a range of "1 to 10" is intended to include any and all subranges between and including the recited minimum value of 1 and the recited maximum value of 10, that is, all subranges beginning with a minimum value equal to or greater than 1 and ending with a maximum value equal to or less than 10, and all subranges in between.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the disclosure, the preferred methods, and materials are now described. All publications mentioned herein are incorporated herein by reference.
The term “cardanol” refers to the phenolic lipid synthesized from anacardic acid, and represented by Formula 2:

Formula 2
wherein n=0, 2, 4, or 6.

The expression “Epoxy equivalent weight (EEW)” refers to the weight of the epoxy resin in grams that contains one equivalent of epoxy.
The expression “Dry film thickness (DFT)” refers to the thickness of a coating (having single or multiple layers) which is measured above the substrate.
In one aspect, an epoxy ester urethane resin is disclosed. The disclosed epoxy ester urethane resin comprises cardanol modified epoxy ester urethane resin represented by Formula 1:

Formula 1
wherein:
n is 2-5;
R is C14-C18 fatty acid carbon chain; and
R` is O-Cardanol modified epoxy ester.
In another aspect, a process for preparing the disclosed epoxy ester urethane resin is described. Said process comprises the steps of:
a) reacting 10-35 wt.% of cardanol and 30-60 wt.% of a base epoxy resin having an EEW of 300-975 to obtain a cardanol modified epoxy resin;
b) reacting 40-70 wt.% of the cardanol modified epoxy resin with 15-30 wt.% of a C14-C18 fatty acid having an iodine value of 110-180 gm I2 /100gm and an acid value of 195-205 mg KOH /gm to obtain a cardanol modified epoxy ester; and

c) reacting 80-95 wt.% of the cardanol modified epoxy ester with 1-5 wt.% of a polyisocyanate to obtain the epoxy ester urethane resin comprising cardanol modified epoxy ester urethane resin.

Thus, the disclosed cardanol modified epoxy ester urethane resin is a reaction product of 30-60 wt.% of a base epoxy resin having an EEW in a range of 300-975, 10-35 wt.% of cardanol, 15-30 wt.% of a C14-C18 fatty acid and 1-5 wt.% of a polyisocyanate. In some embodiments, the cardanol modified epoxy ester urethane resin is a reaction product of 45-59 wt.% of the base epoxy resin having the EEW in the range of 450-550, 15-25 wt.% of cardanol, 17-29 wt.% of the C14-C18 fatty acid and 1.50-2.5 wt.% of the polyisocyanate.

In the disclosed process, the reaction of the base epoxy resin with cardanol introduces hydroxyl functionalities and a long unsaturated alkyl chain into the epoxy backbone of the epoxy resin. The cardanol-modified epoxy resin is further reacted with the unsaturated C14-C18 fatty acid to achieve mineral turpentine solubility and hydrophobicity in the resultant cardanol-modified epoxy ester resin. The obtained cardanol-modified epoxy ester resin, which has residual free hydroxyls, is further reacted with polyisocyanate to create urethane linkages, resulting in the cardanol-modified epoxy ester urethane resin having exceptional drying, mechanical, and saltwater resistance properties. Thus, the disclosed epoxy ester urethane resin, when used in coating applications, exhibits high corrosion resistance and improved mechanical properties.

In an embodiment, the base epoxy resin is selected from the group consisting of bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, resorcinol diglycidyl ether, bisphenol S diglycidyl ether, diglycidyl ether of bisphenol, epoxy novolac resin, and combinations thereof. In some embodiments, the base epoxy resin is bisphenol A diglycidyl ether. In an embodiment, the base epoxy resin has an EEW in the range of 300-975. In some embodiments, the base epoxy resin has the EEW of 450-550. In an embodiment, the base epoxy resin has an average molecular weight in the range of 700-1200 Dalton. In some embodiments, the base epoxy resin has the average molecular weight of 1500 Dalton.

The fatty acid is any fatty acid which comprises unsaturated fatty acid moieties. In an embodiment, the C14-C18 fatty acid is selected from the group consisting of soya oil fatty acid, linseed oil fatty acid, sunflower fatty acid, safflower fatty acid, tall oil fatty acid, dehydrated castor oil fatty acid, and combinations thereof. In some embodiments, the C14-C18 fatty acid is represented by Formula 3.

Formula 3

In an embodiment, the C14-C18 fatty acid has an iodine value in the range of 110-180 gm I2 /100gm. In some embodiments, the C14-C18 fatty acid has the iodine value in the range of 130-160 gm I2 /100gm. In an embodiment, the C14-C18 fatty acid has an acid value in a range of 195-205. In some embodiments, the C14-C18 fatty acid has the acid value in the range of 197-202.

In an embodiment, the polyisocyanate is selected from the group consisting of toluene di-isocyanate, isophorone di-isocyanate, methylene diphenyl diisocyanate, hexamethylene diisocyanate, and combinations thereof. In some embodiments, the polyisocyanate is toluene di-isocyanate.
An exemplary reaction scheme for obtaining the disclosed epoxy ester urethane resin is provided below:

Epoxy Resin Cardanol

Cardanol Modified Epoxy Resin

Cardanol Modified Epoxy Ester

Epoxy Ester Urethane Resin
In the disclosed process, cardanol is reacted with the base epoxy resin at an elevated temperature. In an embodiment, the reaction of cardanol with the base epoxy resin is carried out at a reaction temperature in a range of 150-240ºC for 1-2 hours. In some embodiments, the reaction of cardanol with the base epoxy resin is carried out at the reaction temperature in the range of 200 to 240ºC for 1 hour.

The reaction of cardanol with the base epoxy resin is carried out in the presence of a first catalyst. In an embodiment, the first catalyst is selected from the group consisting of triphenyl phosphine, triethanol amine, benzyltrimethylammonium chloride, 2-methylimidazole, 2-phenylimidazole, triphenylphosphonium iodide, and tetramethylammonium chloride. In some embodiments, the first catalyst is triphenyl phosphine. In an embodiment, the first catalyst is added in an amount in a range of 0.01-0.5 wt.%. In some embodiments, the first catalyst is added in the amount of 0.02 wt.%.

In the next step, the cardanol modified epoxy resin is maintained at 200-210°C till dilution viscosity (60% in xylene) on Gardner scale @ 25°C = K-Y is achieved. In an embodiment, the resultant cardanol modified epoxy resin has the viscosity on Gardner scale @ 25°C (60% in xylene) = L-Y

Once the desired viscosity is achieved, the cardanol modified epoxy resin is cooled to a temperature in a range of 150-200°C. In some embodiments, the cardanol modified epoxy resin is cooled to 165-175°C.
After cooling, the obtained cardanol modified epoxy resin is reacted with the C14-C18 fatty acid to obtain the cardanol modified epoxy ester. In an embodiment, this reaction takes place at a temperature in a range of 225-235ºC for 1-2 hours. In some embodiments, the cardanol modified epoxy resin is reacted with the C14-C18 fatty acid at the temperature of 230ºC for 1.5 hours.
In an embodiment, the reaction of the cardanol modified epoxy resin with the C14-C18 fatty acid is carried out in the presence of a second catalyst, a silicone defoamer and a reflux solvent.
In an embodiment, the second catalyst is selected from the group consisting of zinc acetate dihydrate, dibutyl tin oxide, lithium hydroxide, calcium oxide, zirconium octoate, calcium octoate, lithium stearate and zinc oxide. In some embodiments, the second catalyst is zinc acetate dihydrate. In an embodiment, the second catalyst is added in an amount in a range of 0.01-1 wt.%. In some embodiments, the second catalyst is added in the amount of 0.02 wt.%. In an embodiment, the silicone defoamer is added in an amount in a range of 0.001-0.1 wt.%. In some embodiments, the silicone defoamer is added in the amount of 0.01 wt.%. In an embodiment, the reflux solvent is added in an amount in a range of 2-5 wt.%. In some embodiments, the reflux solvent is added in the amount in the range of 3-5 wt.%. In an embodiment, the reflux solvent is mixed xylene.
The obtained cardanol modified epoxy ester is maintained at a reaction temperature in a range of 235-240°C for a time period ranging between 1-2 hours till an acid value of <5 KOH/g and viscosity on Gardner scale @ 25°C (60% in xylene) = I-P is achieved.
In an embodiment, after achieving the desired acid value and viscosity, the cardanol modified epoxy ester is diluted in a solvent. Any known aliphatic or aromatic hydrocarbon solvents can be used. In an embodiment, the solvent is mixed xylene. In an embodiment, the cardanol modified epoxy ester is diluted with mixed xylene to obtain 60±1% solid containing cardanol modified epoxy ester. In an embodiment, the resultant cardanol modified epoxy ester has an acid value in a range of 0.1-10 KOH/g and viscosity on Gardner scale @ 25°C (60% in xylene) = G-P. In an embodiment, the resultant cardanol modified epoxy ester has an acid value in a range of 0.1-10 mg KOH/g. In some embodiments, the resultant cardanol modified epoxy ester has the acid value in the range of 0.5-8 mg KOH/g. In an embodiment, the resultant cardanol modified epoxy ester has a viscosity on Gardner scale @ 25°C (60% in xylene) = G-P. In some embodiments, the resultant cardanol modified epoxy ester has the viscosity on Gardner scale @ 25°C (60% in xylene) = I-P.
In the next step, the cardanol modified epoxy ester is cooled at to a low temperature in a range of 65-85°C. In some embodiments, the cardanol modified epoxy ester is cooled to 70-75°C.
Post cooling, the obtained cardanol modified epoxy ester is reacted with polyisocyanate to obtain a reaction mixture. In an embodiment, this reaction is carried out at a temperature in a range of 70-115ºC. In some embodiments, the reaction is carried out at the temperature in the range of 70-75ºC. The reaction of the cardanol modified epoxy ester with polyisocyanate is carried out in the presence of a solvent under continuous stirring. In an embodiment, the solvent is mixed xylene.
In the next step, the temperature of this reaction mixture is increased till a constant viscosity is achieved to obtain the epoxy ester urethane resin comprising cardanol modified epoxy ester urethane resin having Formula I. In an embodiment, the temperature is increased to 85-110 ºC till the viscosity on Gardner scale @ 25°C (60% in xylene) = U-Z3 is achieved. In some embodiments, the temperature is increased to 90-95ºC till the viscosity on Gardner scale @ 25°C (60% in xylene) = Z-Z4 is achieved.
In an embodiment, the obtained epoxy ester urethane resin has an acid value in a range of 0.1-5 mg KOH/gm. In some embodiments, the obtained epoxy ester urethane resin has the acid value in the range of 0.5-3 mg KOH/gm.
In an embodiment, the obtained epoxy ester urethane resin has a % non-volatile matter (NVM) in a range of 55-65%. In some embodiments, the obtained epoxy ester urethane resin has the % NVM in the range of 58-62%.
In an embodiment, the obtained epoxy ester urethane resin has a viscosity at 25 °C on Gardner scale (60% in xylene) = U-Z4. In some embodiments, the obtained epoxy ester urethane resin has the viscosity at 25°C on Gardner scale = Z-Z4.
In an embodiment, the obtained epoxy ester urethane resin has an epoxy ester urethane resin: xylene compatibility of at least 1:10. In some embodiments, the obtained epoxy ester urethane has the epoxy ester urethane resin: xylene compatibility of 1: Infinite.
In an embodiment, the obtained epoxy ester urethane has an epoxy ester urethane resin: mineral turpentine oil compatibility of at least 1:4. In some embodiments, the obtained epoxy ester urethane has the epoxy ester urethane resin: mineral turpentine oil compatibility of 1:10.
The present disclosure also relates to a coating composition comprising the above disclosed epoxy ester urethane resin.
The coating composition includes other optional additives. The optional additives that are added are the components that are generally known to be useful for the preparation, storage, application, and curing of the coating composition. Examples of such additives include, but are not limited to, one or more anticorrosive pigments, inorganic fillers, organic pigments, inorganic pigments, rheology modifiers, dispersing agents, metallic driers, and combinations thereof.
In an embodiment, the anticorrosive pigment includes but is not limited to zinc oxide, calcium phosphate, strontium phosphosilicates, modified aluminium triphosphate, zinc molybdate, zinc phosphomolybdate, aluminium zinc phosphate, micaceous iron oxide, zinc phosphate, and strontium chromate. In some embodiments, the anticorrosive pigment is zinc phosphate.
Fillers are added in finely divided form in the coating composition. They are added in the coating composition to bring down the cost of the coating composition and to thicken the coating composition. Any known inorganic filler now known or developed in the future can be used. In an embodiment, the inorganic filler includes but is not limited to mica, steatite, dolomite, silica, and barytes. In some embodiments, the inorganic filler is steatite. The amount of the inorganic filler used in the coating composition depends on the characteristics of the filler such as their oil absorption, shape, size, and the properties desired in the coating composition.
The metallic driers used in the coating compositions accelerate the conversion of the coating into a cross-linked dry film through auto-oxidative polymerization. In an embodiment, the metallic driers include, but are not limited to, calcium octoate, manganese octoate, and zirconium octoate.
The invention will now be described with respect to the following examples which do not limit the disclosed method in any way and only exemplify the claimed method. It will be apparent to those skilled in the art that various modifications and variations can be made to the method/process of the present disclosure without departing from the scope of the disclosure. Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of the method/process disclosed herein.
Examples

Example 1: Preparation of epoxy ester urethane resin in accordance with an embodiment of the present disclosure.

Materials: The reactants used for the preparation of the cardanol modified epoxy ester and the epoxy ester urethane resin along with their respective weight percentages are listed in Table 1a and Table 1b, respectively.

Table 1a: Reactants used for the preparation of the cardanol modified epoxy ester
S. No. Reactants Parts by weight
1. Diglycidyl ether of bisphenol A (EEW 900-975) 45.57
2. Cardanol 30.38
3. Triphenyl phosphine 0.01
4. Soya oil fatty acid 18.97
5. Zinc acetate dihydrate 0.02
6. Silicon defoamer 0.01
7. Mixed xylene 4.86
Total 100

Step 1: Preparation of the cardanol modified epoxy ester: In a four-necked reactor flask equipped with a temperature controller, heating mantle, nitrogen sparger, overhead stirrer, and Dean Stark assembly, diglycidyl ether of bisphenol A with EEW 900-975, and cardanol as mentioned in Table 1a above were charged and heated to 120-130°C to obtain a first reaction mass. To this first reaction mass, triphenyl phosphine was added followed by heating at 210°C for 1-2 hours. The reaction mass was maintained at 200-210°C till a dilution viscosity (60% in xylene) on Gardner scale @25°C = W-Y was achieved. After achieving the desired viscosity, the reaction mass was cooled to a temperature of 165-175°C. To the cooled reaction mass, soya oil fatty acid, lithium stearate, silicon defoamer and mixed xylene as mentioned in Table 1a were added to form a second reaction mass. The obtained second reaction mass was heated at 235-240°C for 1-2 hours and maintained till dilution viscosity (60% in xylene) on Gardner scale @25°C of I-N and acid value of <10 mg KOH/g were achieved. Once the desired viscosity and the acid value were achieved, to the second reaction mass, mixed xylene was added to obtain 60±1% solids containing cardanol modified epoxy ester having viscosity on Gardner scale @ 25°C = M-N and an acid value of 7.37 mg KOH/g.

Table 1b: Reactants used for the preparation of the epoxy ester urethane resin
S. No. Reactants Parts by weight
1. Cardanol modified epoxy ester (60% solution in mixed xylene) 97.50
2. Toluene diisocyanate 1.50
3. Mixed xylene 1.00
Total 100

Step II- Preparation of epoxy ester urethane resin: The cardanol modified epoxy ester obtained in step 1 was cooled to a temperature of 70-75 °C. To the cooled cardanol modified epoxy ester, toluene di-isocyanate and mixed xylene as mentioned in Table 1b above were added to form a mixture. The obtained mixture was continuously stirred for 5-10 minutes. Post stirring, the mixture was maintained at a temperature of 90-95°C till a constant viscosity was achieved to obtain the epoxy ester urethane resin.
Product Characterization: Table 1c provides characteristics of the epoxy ester urethane resin obtained above.
Table 1c: Characteristics of the Epoxy Ester Urethane Resin

S. No. Parameter Characteristic
1. % NVM (120 °C/ 60 mins) 60.10
2. viscosity on Gardner scale @ 25°C W+
3. Mineral Turpentine Oil (MTO) tolerance 1:1
4. Acid Value (mg KOH /gm) 6.85

Example 2: Preparation of epoxy ester urethane resin in accordance with an embodiment of the present disclosure.
Materials: The reactants used for the preparation of cardanol modified epoxy ester and epoxy ester urethane resin along with their respective weight percentages are listed in Table 2a and Table 2b respectively.
Table 2a: Reactants used for the preparation of cardanol modified epoxy ester
S.No. Reactants Parts by weight
1. Diglycidyl ether of bisphenol A (EEW 450- 550 @ 75% in Xylene) 55.83
2. Cardanol 20.83
3. Triphenyl phosphine 0.01
4. Soya oil fatty acid 20.83
5. Zinc acetate dihydrate 0.02
6. Silicon defoamer 0.01
7. Mixed xylene 3.12
Total 100
Step 1: Preparation of cardanol modified epoxy ester: In a four-necked reactor flask equipped with a temperature controller, heating mantle, nitrogen sparger, overhead stirrer and Dean Stark assembly, diglycidyl ether of bisphenol, and cardanol as per the quantities mentioned in Table 2a above, were taken and heated to 120-130°C to obtain a first reaction mass. To the first reaction mass, triphenyl phosphine was added followed by heating at 210°C for 1-2 hours. Recovered xylene was collected. The percentage solid in the batch at this stage was found to be approximately 93-95%. The reaction mass was maintained at 200-210°C till a dilution viscosity on Gardner scale @25°C (60% in xylene) = W-Y was achieved. After achieving the desired viscosity, the reaction mass was cooled to a temperature of 165-175°C. To the cooled reaction mass, soya oil fatty Acid, zinc acetate dihydrate, silicon defoamer and mixed xylene as mentioned in Table 2a were added to form a second reaction mass. The obtained second reaction mass was heated at 235-240°C for 1-2 hours and maintained at this temperature till dilution viscosity on Gardner scale @25°C (60% in xylene) of I-N and an acid value of <10 mg KOH/g were achieved. Once the desired viscosity and the acid value were achieved, to the second reaction mass, mixed xylene was added to obtain 60±1% solids containing cardanol modified epoxy ester having viscosity on Gardner scale @25 °C = I-J, an acid value of 2.43 mg KOH/g and % NVM of 61.51.
Table 2b: Reactants used for the preparation of epoxy ester urethane resin
S.No. Reactants Parts by weight
1. Cardanol modified epoxy ester (60% solution in mixed xylene), obtained in Step I 97.50
2. Toluene diisocyanate 1.50
3. Mixed xylene 1.00
Total 100

Step II- Preparation of epoxy ester urethane resin: The cardanol modified epoxy ester obtained in step 1 was cooled to a temperature of 70-75°C. To the cooled cardanol modified epoxy ester, toluene di-isocyanate and mixed xylene as mentioned in Table 2b were added to form a mixture. The obtained mixture was continuously stirred for 5-10 minutes. Post stirring, the mixture was maintained at a temperature of 90-95°C till a constant viscosity was achieved to obtain the epoxy ester urethane resin.
Product Characterization: Table 2c provides characteristics of the epoxy ester urethane resin obtained above.
Table 2c: Characteristics of the Epoxy Ester Urethane Resin
S. No. Parameter Characteristic
1. % NVM (120 °C / 60 mins) 60.92
2. Viscosity on Gardner scale at 25°C V-
3. MTO tolerance 1:5
4. Acid Value (mg KOH /gm) 2.24
Example 3: Preparation of epoxy ester urethane resin in accordance with an embodiment of the present disclosure.
Materials: The reactants used for the preparation of cardanol modified epoxy ester and epoxy ester urethane resin along with their respective weight percentages are listed in Table 3a and Table 3b respectively.
Table 3a: Reactants used for the preparation of cardanol modified epoxy ester
S.No. Reactants Parts by weight
1. Diglycidyl ether of bisphenol A (EEW 450- 550 @ 75% in Xylene) 55.19
2. Cardanol 20.83
3. Triphenyl phosphine 0.01
4. Soya oil fatty Acid 20.83
5. Zinc acetate dihydrate 0.02
6. Silicon defoamer 0.01
7. Mixed xylene 3.12
Total 100
Step 1: Preparation of cardanol modified epoxy ester: In a four-necked reactor flask equipped with a temperature controller, heating mantle, nitrogen sparger, overhead stirrer and Dean Stark assembly, diglycidyl ether of bisphenol A, and cardanol as mentioned in Table 3a above were taken and heated to 120-130°C to obtain a first reaction mass. To the first reaction mass, triphenyl phosphine was added followed by heating at 210°C for 1-2 hours. Recovered xylene was collected. Batch solid at this stage is approximately 93-95%. The reaction mass was maintained at 200-210 °C till a dilution viscosity (60% in xylene) on Gardner scale @ 25°C = W-Y was achieved. After achieving the desired viscosity, the reaction mass was cooled to a temperature of 165-175 °C. To the cooled reaction mass, soya oil fatty Acid, zinc acetate dihydrate, silicon defoamer and mixed xylene as mentioned in Table 3a were added to form a second reaction mass. The obtained second reaction mass was heated at 235-240°C for 1-2 hours and maintained till dilution viscosity (60% in xylene) on Gardner scale @25°C of I-N and an acid value of <5 mg KOH/g were achieved. Once the desired viscosity and the acid value were achieved, to the second reaction mass, mixed xylene was added to obtain 60±1% solids containing cardanol modified epoxy ester having viscosity on Gardner scale @25 °C = I-J, an acid value of 2.43 mg KOH/g and % NVM of 61.51.
Table 3b: Reactants used for the preparation of epoxy ester urethane resin
S.No. Reactants Parts by weight
1. Cardanol modified epoxy ester (60% solution in mixed xylene) 96.5
2. Toluene diisocyanate 2.1
3. Mixed xylene 1.4
Total 100

Step II- Preparation of epoxy ester urethane resin: The cardanol modified epoxy ester obtained in step 1 was cooled to a temperature of 70-75 °C. To the cooled cardanol modified epoxy ester, toluene di-isocyanate and mixed xylene as mentioned in Table 3b were added to form a mixture. The obtained mixture was continuously stirred for 5-10 minutes. Post stirring, the mixture was maintained at a temperature of 90-95°C till a constant viscosity was achieved to obtain the epoxy ester urethane resin.
Product Characterization: Table 3c provides characteristics of the epoxy ester urethane resin obtained above.
Table 3c: Characteristics of the Epoxy Ester Urethane Resin
S. No. Parameter Characteristic
1. % NVM (120 °C / 60 mins) 60.92
2. Viscosity on Gardner scale at 25°C V-
3. Mineral Turpentine Oil (MTO) tolerance 1:5
4. Acid Value (mg KOH /gm) 2.18

Example 4: Preparation of epoxy ester urethane resin in accordance with an embodiment of the present disclosure.

Materials: The reactants used for the preparation of cardanol modified epoxy ester and epoxy ester urethane resin along with their respective weight percentages are listed in Table 4a and Table 4b respectively.

Table 4a: Reactants used for the preparation of cardanol modified epoxy ester
S.No. Reactants Parts by weight
1. Diglycidyl ether of bisphenol A (EEW 450- 550 @ 75% in Xylene) 51.95
2. Cardanol 19.60
3. Triphenyl phosphine 0.00
4. Soya oil fatty Acid 25.48
5. Zinc acetate dihydrate 0.02
6. Silicon defoamer 0.00
7. Mixed xylene 2.94
Total 100

Step 1: Preparation of cardanol modified epoxy ester: In a four-necked reactor flask equipped with a temperature controller, heating mantle, nitrogen sparger, overhead stirrer and Dean Stark assembly, diglycidyl ether of bisphenol A (EEW 450- 550 @ 75% in xylene), and cardanol as mentioned in Table 4a above were taken and heated to 120-130°C to obtain a first reaction mass. To the first reaction mass, triphenyl phosphine was added, followed by heating at 210°C for 1-2 hours. Recovered xylene was collected. Batch solid at this stage is approximately 93-95%. The reaction mass was maintained at 200-210 °C till dilution viscosity (60% in xylene) on Gardner scale @25°C = L-N was achieved. After achieving the desired viscosity, the reaction mass was cooled to a temperature of 165-175 °C. To the cooled reaction mass, soya oil fatty acid, zinc acetate dihydrate, silicon defoamer and mixed xylene as mentioned in Table 4a were added to form a second reaction mass. The obtained second reaction mass was heated at 235-240°C for 1-2 hours and maintained till dilution viscosity (60% in xylene) on Gardner scale @25°C =F-L and an acid value of <5 mg KOH/g were achieved. Once the desired viscosity and the acid value were achieved, to the second reaction mass, mixed xylene was added to obtain 60±1% solids containing cardanol modified epoxy ester having viscosity on Gardner scale @25 °C = G-H and an acid value of 1.42 mg KOH/g and % NVM of 59.87.
Table 4b: Reactants used for the preparation of epoxy ester urethane resin
S.No. Reactants Parts by weight
1. Cardanol modified epoxy ester (60% solution in mixed xylene) 97
2. Toluene diisocyanate 1.8
3. Mixed xylene 1.2
Total 100

Step II- Preparation of epoxy ester urethane resin: The cardanol modified epoxy ester obtained in step 1 was cooled to a temperature of 70-75 °C. To the cooled cardanol modified epoxy ester, toluene di-isocyanate and mixed xylene as mentioned in Table 4b were added to form a mixture. The obtained mixture was continuously stirred for 5-10 minutes. Post stirring, the mixture was maintained at a temperature of 90-95°C till a constant viscosity was achieved to obtain the epoxy ester urethane resin.
Product Characterization: Table 4c provides characteristics of the epoxy ester urethane resin obtained above.
Table 4c: Characteristics of the Epoxy Ester Urethane Resin
S. No. Parameter Characteristic
1. % NVM (120 °C/ 60 mins) 60.08
2. Viscosity on Gardner scale at 25°C V-
3. Mineral Turpentine Oil (MTO) tolerance 1:6
4. Acid Value (mg KOH /gm) 1.35

Example 5: Preparation of epoxy ester urethane resin in accordance with an embodiment of the present disclosure.

Materials: The reactants used for the preparation of cardanol modified epoxy ester and epoxy ester urethane resin along with their respective weight percentages are listed in Table 5a and Table 5b respectively.

Table 5a: Reactants used for the preparation of cardanol modified epoxy ester
S.No. Reactants Parts by weight
1. Diglycidyl ether of bisphenol A (EEW 450- 550 @ 75% in Xylene) 58.22
2. Cardanol 16.48
3. Triphenyl phosphine 0.01
4. Soya oil fatty Acid 21.97
5. Zinc acetate dihydrate 0.02
6. Silicon defoamer 0.01
7. Mixed xylene 3.30
Total 100

Step 1: Preparation of cardanol modified epoxy ester: In a four-necked reactor flask equipped with a temperature controller, heating mantle, nitrogen sparger, overhead stirrer and Dean Stark assembly, diglycidyl ether of bisphenol A (EEW 450- 550 @ 75% in xylene), and cardanol as mentioned in Table 5a above were taken and heated to 120-130°C to obtain a first reaction mass. To the first reaction mass, triphenyl phosphine was added and heated at 210°C for 1-2 hours. Recovered xylene was collected. Batch solid at this stage was approximately 93-95%. The reaction mass was maintained at 200-210 °C till dilution viscosity (60% in xylene) on Gardner scale @25°C = L-N was achieved. After achieving the desired viscosity, the reaction mass was cooled to a temperature of 165-175 °C. To the cooled reaction mass, soya oil fatty acid, zinc acetate dihydrate, silicon defoamer and mixed xylene as mentioned in Table 5a were added to form a second reaction mass. The obtained second reaction mass was heated at 235-240°C for 1-2 hours and maintained till dilution viscosity (60% in xylene) on Gardner scale @25°C = F-L and an acid value of <5 mg KOH/g were achieved. Once the desired viscosity and the acid value were achieved, to the second reaction mass, mixed xylene was added to obtain 60±1% solids containing cardanol modified epoxy ester having viscosity on Gardner scale @25 °C = O-P, an acid value of 0.92 mg KOH/g and % NVM of 61.97.
Table 5b: Reactants used in the preparation of epoxy ester urethane resin
S.No. Reactants Parts by weight
1. Cardanol modified epoxy ester (60% solution in mixed xylene) 97
2. Toluene diisocyanate 1.8
3. Mixed xylene 1.2
Total 100
Step II- Preparation of epoxy ester urethane resin: The cardanol modified epoxy ester obtained in step 1 was cooled to a temperature in the range of 70-75 °C. To the cooled cardanol modified epoxy ester, toluene di-isocyanate and mixed xylene as mentioned in Table 5b were added to form a mixture. The obtained mixture was continuously stirred for 5-10 minutes. Post stirring, the mixture was maintained at a temperature of 90-95°C till a constant viscosity was achieved to obtain the epoxy ester urethane resin.
Product Characterization: Table 5c provides characteristics of the epoxy ester urethane resin obtained above.
Table 5c: Characteristics of the Epoxy Ester Urethane Resin
S. No. Parameter Characteristic
1. % NVM (120 °C / 60 mins) 60.25
2. Viscosity on Gardner scale at 25°C Z
3. Mineral Turpentine Oil (MTO) tolerance 1:6
4. Acid Value (mg KOH /gm) 0.77
Example 6: Preparation of epoxy ester urethane resin in accordance with an embodiment of the present disclosure.
Materials: The reactants used for the preparation of cardanol modified epoxy ester and epoxy ester urethane resin along with their respective weight percentages are listed in Table 6a and Table 6b respectively.

Table 6a: Reactants used for the preparation of cardanol modified epoxy ester
S.No. Reactants Parts by weight
1. Diglycidyl ether of bisphenol A (EEW 450- 550 @ 75% in Xylene) 57.59
2. Cardanol 21.73
3. Triphenyl phosphine 0.01
4. Soya oil fatty acid 17.39
5. Zinc acetate dihydrate 0.02
6. Silicon defoamer 0.01
7. Mixed xylene 3.26
Total 100
Step 1: Preparation of cardanol modified epoxy ester: In a four-necked reactor flask equipped with a temperature controller, heating mantle, nitrogen sparger, overhead stirrer and Dean Stark assembly, diglycidyl ether of bisphenol A (EEW 450- 550 @ 75% in xylene), and cardanol as mentioned in Table 6a above were taken and heated to 120-130°C to obtain a first reaction mass. To the first reaction mass, triphenyl phosphine was added, followed by heating at 210°C for 1-2 hours. Recovered xylene was collected. Batch solid at this stage was approximately 93-95%. The reaction mass was maintained at 200-210 °C till dilution viscosity (60% in xylene) on Gardner scale @25°C = L-N was achieved. After achieving the desired viscosity, the reaction mass was cooled to a temperature of 165-175 °C. To the cooled reaction mass, soya oil fatty Acid, zinc acetate dihydrate, silicon defoamer and mixed xylene as mentioned in table 6a were added to form a second reaction mass. The obtained second reaction mass was heated at 235-240°C for 1-2 hours and maintained till dilution viscosity (60% in xylene) on Gardner scale@25°C of F-L and an acid value of <5 mg KOH/g were achieved. Once the desired viscosity and the acid value were achieved, to the second reaction mass, mixed xylene was added to obtain 60±1% solids containing cardanol modified epoxy ester having viscosity on Gardner scale @25 °C = J, an acid value of 0.72 mg KOH/g and % NVM of 60.21.

Table 6b: Reactants used for the preparation of epoxy ester urethane resin
S.No. Reactants Parts by weight
1. Cardanol modified epoxy ester (60% solution in mixed xylene) 97.5
2. Toluene diisocyanate 1.5
3. Mixed xylene 1
Total 100

Step II- Preparation of epoxy ester urethane resin: The cardanol modified epoxy ester obtained in step 1 was cooled to a temperature in the range of 70-75 °C. To the cooled cardanol modified epoxy ester, toluene di-isocyanate and mixed xylene as mentioned in Table 6b were added to form a mixture. The obtained mixture was continuously stirred for 5-10 minutes. Post stirring, the mixture was maintained at a temperature of 90-95°C till a constant viscosity was achieved to obtain the epoxy ester urethane resin.
Product Characterization: Table 6c provides characteristics of the epoxy ester urethane resin obtained above.
Table 6c: Characteristics of the Epoxy Ester Urethane Resin
S. No. Parameter Characteristic
1. % NVM (120 °C/60 mins) 61.2
2. Viscosity on Gardner scale at 25°C V-
3. Mineral Turpentine Oil (MTO) tolerance 1:6
4. Acid Value (mg KOH /gm) 0.68
Example 7: Preparation of epoxy ester urethane resin in accordance with an embodiment of the present disclosure.

Materials: The reactants used for the preparation of cardanol modified epoxy ester and epoxy ester urethane resin along with their respective weight percentages are listed in Table 7a and Table 7b respectively.

Table 7a: Reactants used for the preparation of cardanol modified epoxy ester
S.No. Reactants Parts by weight
1. Diglycidyl ether of bisphenol A (EEW 450- 550 @ 75% in Xylene) 57.59
2. Cardanol 21.73
3. Triphenyl phosphine 0.01
4. Soya oil fatty acid 17.39
5. Zinc acetate dihydrate 0.02
6. Silicon defoamer 0.01
7. Mixed xylene 3.26
Total 100

Step 1: Preparation of cardanol modified epoxy ester: In a four-necked reactor flask equipped with a temperature controller, heating mantle, nitrogen sparger, overhead stirrer and Dean Stark assembly, diglycidyl ether of bisphenol A (EEW 450- 550 @ 75% in xylene), and cardanol as mentioned in Table 6a above were taken, followed by heating to 120-130°C to obtain a first reaction mass. To the first reaction mass, triphenyl phosphine was added and heated at 210°C for 1-2 hours. Recovered xylene was collected. Batch solid at this stage was approximately 93-95%. The reaction mass was maintained at 200-210 °C till dilution viscosity (60% in xylene) on Gardner scale @25°C = L-N was achieved. After achieving the desired viscosity, the reaction mass was cooled to a temperature of 165-175 °C. To the cooled reaction mass, soya oil fatty acid, zinc acetate dihydrate, silicon defoamer and mixed xylene as mentioned in Table 6a were added to form a second reaction mass. The obtained second reaction mass was heated at 235-240°C for 1-2 hours and maintained till dilution viscosity (60% in xylene) on Gardner scale @25°C = F-L and an acid value of <5 mg KOH/g were achieved. Once the desired viscosity and the acid value were achieved, to the second reaction mass, mixed xylene was added to obtain 60±1% solids containing cardanol modified epoxy ester having viscosity on Gardner scale @25 °C = J and an acid value of 0.72 mg KOH/g and % NVM of 60.21.
Table 7b: Reactants used for the preparation of epoxy ester urethane resin
S.No. Reactants Parts by weight
1. Cardanol modified epoxy ester (60% solution in mixed xylene) 96.50
2. Toluene diisocyanate 2.10
3. Mixed xylene 1.40
Total 100

Step II- Preparation of epoxy ester urethane resin: The cardanol modified epoxy ester obtained in step 1 was cooled to a temperature in the range of 70-75 °C. To the cooled cardanol modified epoxy ester, toluene di-isocyanate and mixed xylene as mentioned in Table 7b were added to form a mixture. The obtained mixture was continuously stirred for 5-10 minutes. Post stirring, the mixture was maintained at a temperature of 90-95°C till a constant viscosity was achieved to obtain the epoxy ester urethane resin.
Product Characterization: Table 7c provides characteristics of the epoxy ester urethane resin obtained above.
Table 7c: Characteristics of the Epoxy Ester Urethane Resin
S. No. Parameter Characteristic
1. % NVM (120 °C/ 60 mins) 61.2
2. Viscosity on Gardner scale at 25°C V-
3. Mineral Turpentine Oil (MTO) tolerance 1:6
4. Acid Value (mg KOH /gm) 0.64

Example 8: Preparation of epoxy ester urethane resin in accordance with an embodiment of the present disclosure.

Materials: The reactants used for the preparation of cardanol modified epoxy ester and epoxy ester urethane resin along with their respective weight percentages are listed in Table 8a and Table 8b respectively.

Table 8a: Reactants used for the preparation of cardanol modified epoxy ester
S.No. Reactants Parts by weight
1. Diglycidyl ether of bisphenol A (EEW 450- 550 @ 75% in Xylene) 56.59
2. Cardanol 14.98
3. Triphenyl phosphine 0.01
4. Soya oil fatty acid 25.48
5. Zinc acetate dihydrate 0.02
6. Silicon defoamer 0.01
7. Mixed xylene 2.92
Total 100

Step 1: Preparation of cardanol modified epoxy ester: In a four-necked reactor flask equipped with a temperature controller, heating mantle, nitrogen sparger, overhead stirrer and Dean Stark assembly, diglycidyl ether of bisphenol A (EEW 450- 550 @ 75% in xylene), and cardanol as mentioned in Table 8a above were taken, followed by heating to 120-130°C to obtain a first reaction mass. To the first reaction mass, triphenyl phosphine was added and heated at 210°C for 1-2 hours. Recovered xylene was collected. Batch solid at this stage was approximately 93-95%. The reaction mass was maintained at 200-210 °C till dilution viscosity (60% in xylene) on Gardner scale @25°C = L-N was achieved. After achieving the desired viscosity, the reaction mass was cooled to a temperature of 165-175 °C. To the cooled reaction mass, soya oil fatty acid, zinc acetate dihydrate, silicon defoamer and mixed xylene as mentioned in Table 8a were added to form a second reaction mass. The obtained second reaction mass was heated at 235-240°C for 1-2 hours and maintained till dilution viscosity (60% in xylene) on Gardner scale @25°C = F-L and an acid value of <5 mg KOH/g were achieved. Once the desired viscosity and the acid value were achieved, to the second reaction mass, mixed xylene was added to obtain 60±1% solids containing cardanol modified epoxy ester having viscosity on Gardner scale @ 25°C = J, an acid value of 2.8 mg KOH/g and % NVM of 60.05.

Table 8b: Reactants used for the preparation of epoxy ester urethane resin
S.No. Reactants Parts by weight
1. Cardanol modified epoxy ester (60% solution in mixed xylene) 97.00
2. Toluene diisocyanate 1.80
3. Mixed xylene 1.20
Total 100

Step II- Preparation of epoxy ester urethane resin: The cardanol modified epoxy ester obtained in step 1 was cooled to a temperature in the range of 70-75 °C. To the cooled cardanol modified epoxy ester, toluene di-isocyanate and mixed xylene as mentioned in Table 8b were added to form a mixture. The obtained mixture was continuously stirred for 5-10 minutes. Post stirring, the mixture was maintained at a temperature of 90-95°C till a constant viscosity was achieved to obtain the epoxy ester urethane resin.
Product Characterization: Table 8c provides characteristics of the epoxy ester urethane resin obtained above.

Table 8c: Characteristics of the Epoxy Ester Urethane Resin
S. No. Parameter Characteristic
1. % NVM (120 °C / 60 mins) 59.49
2. Viscosity on Gardner scale at 25°C Z3+
3. Mineral Turpentine Oil (MTO) tolerance 1:6
4. Acid Value (mg KOH /gm) 2.67

Example 9: Preparation of epoxy ester urethane resin in accordance with an embodiment of the present disclosure.

Materials: The reactants used for the preparation of cardanol modified epoxy ester and epoxy ester urethane resin along with their respective weight percentages are listed in Table 9a and Table 9b respectively.

Table 9a: Reactants used for the preparation of cardanol modified epoxy ester
S.No. Reactants Parts by weight
1. Diglycidyl ether of bisphenol A (EEW 450- 550 @ 75% in Xylene) 53.92
2. Cardanol 14.98
3. Triphenyl phosphine 0.01
4. Soya oil fatty acid 28.15
5. Zinc acetate dihydrate 0.02
6. Silicon defoamer 0.01
7. Mixed xylene 2.92
Total 100

Step 1: Preparation of cardanol modified epoxy ester: In a four-necked reactor flask equipped with a temperature controller, heating mantle, nitrogen sparger, overhead stirrer and Dean Stark assembly, diglycidyl ether of bisphenol A (EEW 450- 550 @ 75% in xylene), and cardanol as mentioned in Table 9a above were taken, followed by heating to 120-130°C to obtain a first reaction mass. To the first reaction mass, triphenyl phosphine was added and heated at 210°C for 1-2 hours. Recovered xylene was collected. Batch solid at this stage was approximately 93-95%. The reaction mass was maintained at 200-210 °C till dilution viscosity on Gardner scale @ 25°C (60% in xylene) = of L-N was achieved. After achieving the desired viscosity, the reaction mass was cooled to a temperature of 165-175 °C. To the cooled reaction mass, soya oil fatty acid, zinc acetate dihydrate, silicon defoamer and mixed xylene as mentioned in Table 9a were added to form a second reaction mass. The obtained second reaction mass was heated at 235-240°C for 1-2 hours and maintained till dilution viscosity (60% in xylene) on Gardner scale @25°C = F-L and an acid value of <5 mg KOH/g were achieved. Once the desired viscosity and the acid value were achieved, to the second reaction mass, mixed xylene was added to obtain 60±1% solids containing cardanol modified epoxy ester having viscosity on Gardner scale @ 25°C = J, an acid value of 2.8 mg KOH/g and % NVM 60.05.
Table 9b: Reactants used for the preparation of epoxy ester urethane resin
S.No. Reactants Parts by weight
1. Cardanol modified epoxy ester (60% solution in mixed xylene) 97.00
2. Toluene diisocyanate 1.80
3. Mixed xylene 1.20
Total 100
Step II- Preparation of epoxy ester urethane resin: The cardanol modified epoxy ester obtained in step 1 was cooled to a temperature in the range of 70-75 °C. To the cooled cardanol modified epoxy ester, toluene di-isocyanate and mixed xylene as mentioned in Table 9b were added to form a mixture. The obtained mixture was continuously stirred for 5-10 minutes. Post stirring, the mixture was maintained at a temperature of 90-95°C till a constant viscosity was achieved to obtain the epoxy ester urethane resin.
Product Characterization: Table 9c provides characteristics of the epoxy ester urethane resin obtained above.
Table 9c: Characteristics of the Epoxy Ester Urethane Resin
S. No. Parameter Characteristic
1. % NVM (120 °C / 60 mins) 59.82
2. Viscosity on Gardner scale at 25°C Z+
3. Mineral Turpentine Oil (MTO) tolerance 1:8
4. Acid Value (mg KOH /gm) 2.58

Example 10: Preparation of epoxy ester urethane resin in accordance with an embodiment of the present disclosure.
Materials: The reactants used for the preparation of cardanol modified epoxy ester and epoxy ester urethane resin along with their respective weight percentages are listed in Table 10a and Table 10b respectively.
Table 10a: Reactants used for the preparation of cardanol modified epoxy ester
S.No. Reactants Parts by weight
1. Diglycidyl ether of bisphenol A (EEW 450- 550 @ 75% in Xylene) 54.63
2. Cardanol 18.38
3. Triphenyl phosphine 0.01
4. Soya oil fatty acid 23.96
5. Zinc acetate dihydrate 0.02
6. Silicon defoamer 0.01
7. Mixed xylene 2.99
Total 100

Step 1: Preparation of cardanol modified epoxy ester: In a four-necked reactor flask equipped with a temperature controller, heating mantle, nitrogen sparger, overhead stirrer and Dean Stark assembly, diglycidyl ether of bisphenol A (EEW 450- 550 @ 75% in xylene), and cardanol as mentioned in Table 10a above were taken, followed by heating to 120-130°C to obtain a first reaction mass. To the first reaction mass, triphenyl phosphine was added and heated at 210°C for 1-2 hours. Recovered xylene was collected. Batch solid at this stage was approximately 93-95%. The reaction mass was maintained at 200-210 °C till dilution viscosity on Gardner scale @ 25°C (60% in xylene) = L-N was achieved. After achieving the desired viscosity, the reaction mass was cooled to a temperature of 165-175 °C. To the cooled reaction mass, soya oil fatty acid, zinc acetate dihydrate, silicon defoamer and mixed xylene as mentioned in Table 10a were added to form a second reaction mass. The obtained second reaction mass was heated at 235-240°C for 1-2 hours and maintained till dilution viscosity (60% in xylene) on Gardner scale@25°C = F-L and an acid value of <5 mg KOH/g were achieved. Once the desired viscosity and the acid value were achieved, to the second reaction mass, mixed xylene was added to obtain 60±1% solids containing cardanol modified epoxy ester having viscosity on Gardner scale @25 °C = J, an acid value of 2.8 mg KOH/g and % NVM 60.05.
Table 10b: Reactants used for the preparation of epoxy ester urethane resin
S.No. Reactants Parts by weight
1. Cardanol modified epoxy ester (60% solution in mixed xylene) 96.66
2. Toluene diisocyanate 2.00
3. Mixed xylene 1.34
Total 100
Step II- Preparation of epoxy ester urethane resin: The cardanol modified epoxy ester obtained in step 1 was cooled to a temperature in the range of 70-75 °C. To the cooled cardanol modified epoxy ester, toluene di-isocyanate and mixed xylene as mentioned in Table 10b were added to form a mixture. The obtained mixture was continuous stirred for 5-10 minutes. Post stirring, the mixture was maintained at a temperature of 90-95°C till a constant viscosity was achieved to obtain the epoxy ester urethane resin.
Product Characterization: Table 10c provides characteristics of the epoxy ester urethane resin obtained above.
Table 10c: Characteristics of the Epoxy Ester Urethane Resin
S. No. Parameter Characteristic
1. % NVM (120 Deg C/ 60 mins) 60.14
2. Viscosity on Gardner scale at 25°C Z2-Z3
3. Mineral Turpentine Oil (MTO) tolerance 1:9
4. Acid Value (mg KOH /gm) 2.73

Example 11: Preparation of the coating composition based on the epoxy ester urethane resin in accordance with an embodiment of the present disclosure.
A coating composition was prepared using the epoxy ester urethane resin of examples 9 and 10.
Materials: The ingredients used for the preparation of coating composition along with their respective weight percentages are listed in Table 11a.
Table 11a: Ingredients used for the preparation of the coating composition
S.No. Reactants Parts by weight
Mill Base Epoxy Primer Grey
1. Epoxy ester urethane resin (Example 9 & 10)
2. Mixed xylene 19.00
3. Carbon black N220 0.10
4. Zinc phosphate 10.00
5. Steatite 500 micron 24.51
6. TiO2 rutile 2.00
7. Soya lecithin 0.40
8. Benton SD2 0.15
9. Glycidyloxy propyl trimethoxy silane
1.00
Thinning
10. Calcium octoate 3% 1.00
11. Manganese octoate 5% 0.05
12. Zirconium octoate 18% 0.05
13. MEK oxime 0.10
14. Borchi oxy coat 1310 (Iron complex 1%) 0.20
TOTAL 100
Product Characterization: Table 11b provides characteristics of the coating film obtained using the coating composition prepared above.
Table 11b: Characteristics of the coating film
S. No Property Epoxy Primer Grey
1. Dry Film Thickness (microns) 2 coats 55-60
2. Finish on HG 5+
3. Viscosity at 30°C (K.U) 98
4. Viscosity (K.U) after 15 days accelerated stability 106
5. Surface dry time in minutes (IS 101) 10-15
6. Tack free time in hours (IS 101) 1.5-2
7. Hard dry time in hours (IS 101) 8-10
8. Scratch hardness after 48 hours (gm) (IS 101) 1100
9. Cross cut adhesion (ASTM D 3359) Passes 4 B
10. Salt Spray Resistance (ASTM B117) Passes 1000 hours
11. Flexibility ¼ inch mandrel (ASTM D 522)
Passes
12. Impact resistance (1 Kg front) ISO 6172
Passes

INDUSTRIAL APPLICABILITY
The disclosed epoxy ester urethane resin provides exceptional mechanical and corrosion resistance properties to coating compositions used in decorative and industrial applications, especially for direct-to-metal coating applications.
As illustrated in Example 11, the disclosed coating composition, when applied to a mild steel substrate at a dry film thickness of 55–60 microns in two or more coats with an interval of 8–10 hours between the coats, provides a corrosion resistance performance of 1000 hours or more without any sign of under-film corrosion as per the ASTM B117 salt spray test. Also, the disclosed coating composition passes the flexibility test conducted by a Mandrel bend test (as per ASTM D 522), and impact resistance tested 1 Kg front (as per ISO 6172).
The disclosed epoxy ester urethane resin exhibits good MTO solubility and can be prepared with a low concentration of fatty acids. The said epoxy ester urethane resin provides the required properties at an economical cost.
The disclosed coating composition exhibits good drying and provides a high sheen/semi-gloss finish. ,CLAIMS:1. An epoxy ester urethane resin comprising cardanol modified epoxy ester urethane resin represented by Formula 1:

Formula 1
wherein:
n is 2-5;
R is C14-C18 fatty acid carbon chain; and
R` is O-Cardanol modified epoxy ester.
2. The epoxy ester urethane resin as claimed in claim 1, wherein the cardanol modified epoxy ester urethane resin is a reaction product of:
- 30-60 wt.% of a base epoxy resin having an epoxide equivalent weight of 300-975;
- 10-35 wt.% of cardanol;
- 15-30 wt.% of a C14-C18 fatty acid having an iodine value of 110-180 gm I2 /100gm and an acid value of 195-205; and
- 1-5 wt.% of a polyisocyanate.
3. The epoxy ester urethane resin as claimed in claim 1, wherein the base epoxy resin is selected from the group consisting of bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, resorcinol diglycidyl ether, bisphenol S diglycidyl ether, diglycidyl ether of bisphenols, epoxy novolac resin, and combinations thereof.
4. The epoxy resin as claimed in claim 1, wherein the C14-C18 fatty acid is selected from the group consisting of soya oil fatty acid, linseed oil fatty acid, sunflower fatty acid, safflower fatty acid, tall oil fatty acid, dehydrated castor oil fatty acid, and combinations thereof.
5. The epoxy ester urethane resin as claimed in claim 1, wherein the polyisocyanate is selected from the group consisting of toluene di-isocyanate, isophorone di-isocyanate, methylene diphenyl diisocyanate, hexamethylene diisocyanate, and combinations thereof.
6. The epoxy ester urethane resin as claimed in claim 1, characterized by having an acid value in the range of 0.1- 5 mg KOH/gm, % non-volatile matter in the range of 55-65%, viscosity at 25°C on Gardner scale =U-Z4, epoxy ester urethane resin: xylene compatibility of at least 1:10, and epoxy ester urethane resin: mineral turpentine oil compatibility of at least 1: 4.
7. A process for preparing an epoxy ester urethane resin, said process comprising the steps of:
a) reacting 10-35 wt.% of cardanol and 30-60 wt.% of a base epoxy resin having an epoxide equivalent weight of 300-975 to obtain a cardanol modified epoxy resin;
b) reacting 40-70 wt.% of the cardanol modified epoxy resin with 15-30 wt.% of a C14-C18 fatty acid having an iodine value of 110-180 gm I2 /100gm and an acid value 195-205 mg KOH /gm to obtain a cardanol modified epoxy ester; and
c) reacting 80-95 wt.% of the cardanol modified epoxy ester with 1-5 wt.% of a polyisocyanate to obtain the epoxy ester urethane resin comprising cardanol modified epoxy ester urethane resin represented by Formula 1:

Formula 1
wherein:
n is 2-5;
R is C14-C18 fatty acid carbon chain; and
R` is O-Cardanol modified epoxy ester.
8. The process as claimed in claim 7, wherein the base epoxy resin is selected from the group consisting of bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, resorcinol diglycidyl ether, bisphenol S diglycidyl ether, diglycidyl ether of bisphenols, Epoxy novolac resin, and combinations thereof.
9. The process as claimed in claim 7, wherein the C14-C18 fatty acid is selected from the group consisting of soya oil fatty acid, linseed oil fatty acid, sunflower fatty acid, safflower fatty acid, tall oil fatty acid, and dehydrated castor oil fatty acid, and combinations thereof.
10. The process as claimed in claim 7, wherein the polyisocyanate is selected from the group consisting of toluene di-isocyanate, isophorone di-isocyanate, methylene diphenyl diisocyanate, hexamethylene diisocyanate, and combinations thereof.
11. The process as claimed in claim 7, wherein the reaction of cardanol with the base epoxy resin is carried out at a reaction temperature in the range of 150 to 240ºC.
12. The process as claimed in claim 7, wherein the reaction of cardanol with the base epoxy resin is carried out in the presence of 0.01-0.5wt.% of a first catalyst selected from the group consisting of triphenyl phosphine, triethanol amine, benzyltrimethylammonium chloride, 2-methylimidazole, 2-phenylimidazole, triphenylphosphonium iodide, tetramethylammonium chloride and combinations thereof.
13. The process as claimed in claim 7, wherein the cardanol modified epoxy resin is treated with the C14-C18 fatty acid at a temperature in the range of 225-235ºC to obtain the cardanol modified epoxy ester.
14. The process as claimed in claim 7, wherein the reaction of cardanol modified epoxy resin with the C14-C18 fatty acid is carried out in the presence of a second catalyst, a silicone defoamer and a reflux solvent.
15. The process as claimed in claim 14, wherein the second catalyst is added in an amount in the range of 0.01-1 wt.%, the second catalyst being selected from the group consisting of zinc acetate dihydrate, dibutyl tin oxide, lithium hydroxide, calcium oxide, zirconium octoate, calcium octoate, and zinc oxide.
16. The process as claimed in claim 14, wherein the silicone defoamer is added in an amount in the range of 0.001-0.1 wt.%.
17. The process as claimed in claim 14, wherein the reflux solvent is added in an amount in the range of 2-5 wt.%
18. The process as claimed in claim 7, wherein the cardanol modified epoxy ester is reacted with the polyisocyanate at a reaction temperature in the range of 85-115ºC for 3-5 hours to obtain the epoxy ester urethane resin.
19. A coating composition comprising the epoxy ester urethane resin as claimed in claim 1.
20. The coating composition as claimed in claim 19, further comprising an additive selected from the group consisting of anticorrosive pigments, inorganic fillers, organic pigments, inorganic pigments, rheology modifiers, dispersing agents, metallic driers, and combinations thereof.