Description:TECHNICAL FIELD
The present disclosure relates to field of material science. The present disclosure particularly relates to primer composition that provides for improved adherence, improved corrosion resistance and improved recoating ability. The present disclosure further relates to an article coated with the primer composition and methods of preparing the primer composition and the article.

BACKGROUND OF THE DISCLOSURE
A high-quality anti-corrosion coating is of paramount importance for a number of applications. Providing stable protection of the surface of metal products and structures from external corrosion is the main factor determining the time of their operation. Metal surfaces for use in a wide range of industries, such as automotive, agricultural, aviation, construction and industrial, are particularly susceptible to corrosion and requires protection against corrosive environments. Therefore, it is important that the coatings of metal surfaces are resistant to various chemicals, water and temperature extremes. It is equally important that these coatings have excellent adhesion characteristics.

Thus, there is a need for primer composition having improved properties, such as corrosion resistance, adhesion and durability. The present disclosure provides for a primer composition having said improved properties.

STATEMENT OF THE DISCLOSURE
The present disclosure relates to a primer composition comprising- resin selected from a group comprising grafted epoxy amine resin, grafted epoxy ester resin and a combination thereof; defoaming agent, wetting agent and solvent. The primer composition provides for improved corrosion resistance, improved adherence and improved recoating ability.

The present disclosure further relates to a method of preparing the primer composition described above, said method comprises- i. mixing the resin with the defoaming agent and the wetting agent; and ii. adding the solvent and mixing to obtain the primer composition.

The present disclosure further relates to an article coated with the primer composition described above.
The present disclosure further relates to a method of producing the article described above, the method comprises- coating the article with the primer composition, followed by curing to obtain the article comprising the coating.

BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURES
In order that the present disclosure may be readily understood and put into practical effect, reference will now be made to exemplary embodiments as illustrated with reference to the accompanying figures. The figures together with detailed description below, are incorporated in and form part of the specification, and serve to further illustrate the embodiments and explain various principles and advantages, where:

Figures 1a and 1b illustrates results of bending test conducted on the coated article of the present disclosure, which is painted, wherein a) coated article painted with polyester paint; b) coated article painted with epoxy and polyester paint; and c) coated article painted with epoxy paint.

Figures 2a and 2b illustrates results of cross hatch adhesion test conducted on the coated article of the present disclosure, which is painted, wherein a) coated article painted with polyester paint; b) coated article painted with epoxy and polyester paint; and c) coated article painted with epoxy paint.

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

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

The term ‘comprising’, ‘comprises’ or ‘comprised of’ as used herein are synonymous with ‘including’, ‘includes’, ‘containing’ or ‘contains’ and are inclusive or open-ended and do not exclude additional, non-recited members, elements or method steps.
The recitation of numerical ranges by endpoints includes all numbers and fractions subsumed within the respective ranges, as well as the recited endpoints.

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

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

The present disclosure relates to a primer composition.

The primer composition of the present disclosure is transparent and fast drying.

In some embodiments of the present disclosure, the primer composition demonstrates improved adherence, improved corrosion resistance and improved recoating ability.

The prime composition of the present disclosure comprises- resin selected from a group comprising grafted epoxy amine resin, grafted epoxy ester resin and a combination thereof; defoaming agent, wetting agent and solvent.

In some embodiments of the present disclosure, the grafted epoxy amine resin includes but it is not limited to diamino toluene sulfonic acid grafted epoxy amine.

In an embodiment, the grafted epoxy amine resin is diamino toluene sulfonic acid grafted epoxy amine.

In an embodiment, the grafted epoxy amine resin comprises epoxy amine compound having molecular weight ranging from about 4E+7 to 6E+7 Dalton. The grafted epoxy amine resin comprises water and organic solvent, wherein the water is an amount ranging from about 40 wt.% to 50 wt.% and the organic solvent is in an amount ranging from about 3 wt.% to 4 wt.%. In an embodiment, the organic solvent is a combination of propylene glycol and polyethylene glycol in a ratio of about 2:1.

In an embodiment, the organic solvent in the grafted epoxy amine resin is high flash point solvent which increases flexibility of resin chain.

In some embodiments of the present disclosure, the grafted epoxy ester resin includes but it is not limited to amine blocked para toluene sulfonic acid epoxy ester.

In an embodiment, the grafted epoxy ester resin is amine blocked para toluene sulfonic acid epoxy ester.

In an embodiment, the grafted epoxy ester resin comprises epoxy ester having molecular weight ranging from about 3E+5 to 5E+5 Dalton. The grafted epoxy ester resin comprises water in an amount ranging from about 35 wt.% to 45 wt.%. In an embodiment, the grafted epoxy ester resin is devoid of organic solvent.

In some embodiments of the present disclosure, the epoxy resin is in an amount ranging from about 80 wt.% to 95 wt.%, including all the values in the range, for instance, 80.1 wt.%, 80.2 wt.%, 80.3 wt.%, 80.4 wt.% and so on and so forth.

In some embodiments of the present disclosure, the grafted epoxy amine resin is in an amount ranging from about 80 wt.% to 95 wt.%, including all the values in the range, for instance, 80.1 wt.%, 80.2 wt.%, 80.3 wt.%, 80.4 wt.% and so on and so forth.

In some embodiments of the present disclosure, grafted epoxy ester resin is in an amount ranging from about 80 wt.% to 95 wt.%, including all the values in the range, for instance, 80.1 wt.%, 80.2 wt.%, 80.3 wt.%, 80.4 wt.% and so on and so forth.

The inventors have identified that, resin selected from a group comprising grafted epoxy amine resin, grafted epoxy ester resin and a combination thereof in the primer composition provides improved flexibility and fast curing of the composition upon application on to a substrate, such as metal and/or alloy.

The inventors have also identified that the resin selected from a group comprising grafted epoxy amine resin, grafted epoxy ester resin and a combination thereof in the primer composition provides for improved corrosion resistance, improved film forming property and improved post paintability property.

In some embodiments of the present disclosure, the defoaming agent is selected from a group comprising mineral oil, mineral spirit, and a combination thereof.

In some embodiments of the present disclosure, the defoaming agent is in an amount ranging from about 0.4 wt.% to 1 wt.%. In an embodiment, the defoaming agent is in an amount of about 0.4 wt.%, about 0.5 wt.%, about 0.6 wt.%, about 0.7 wt.%, about 0.8 wt.%, about 0.9 wt.% or about 1 wt.%.

In some embodiments of the present disclosure, the wetting agent includes but it is not limited to ionic solution of polyacrylic copolymer.

In an embodiment, the wetting agent is ionic solution of polyacrylic copolymer.
In an embodiment, the wetting agent is devoid of silicone. The wetting agent comprises about 50% active substance and has viscosity ranging from about 350 mPa.s to 520 mPa.s, including all the values in the range, for instance, 351 mPa.s, 352 mPa.s, 353 mPa.s, 354 mPa.s and so on and so forth.

In some embodiments of the present disclosure, the wetting agent is in an amount ranging from about 0.4 wt.% to 0 wt.%. In an embodiment, the wetting agent is in an amount about 0.4 wt.%, about 0.5 wt.%, about 0.6 wt.%, about 0.7 wt.%, about 0.8 wt.%, about 0.9 wt.% or about 1 wt.%.

In some embodiments of the present disclosure, the solvent includes but it is not limited to demineralized water.

In an embodiment, the solvent is demineralized water.

In some embodiments of the present disclosure, the solvent is in an amount ranging from about 3 wt.% to 20 wt.%, including all the values in the range, for instance, 3.1 wt.%, 3.2 wt.%, 3.3 wt.%, 3.4 wt.% and so on and so forth.

In some embodiments of the present disclosure, the primer composition has pH ranging from about 6.8 to 7.2. In an embodiment, the primer composition has pH of about 6.8, about 6.9, about 7.0, about 7.1 or about 7.2.

In some embodiments of the present disclosure, the primer composition has specific gravity ranging from about 0.95 to 1.05. In an embodiment, the primer composition has specific gravity of about 0.95, about 0.96, about 0.97, about 0.98, about 0.99, about 1.0, about 1.01, about 1.02, about 1.03, about 1.04 or about 1.05.

In some embodiments of the present disclosure, the primer composition has non-volatile matter content ranging from about 47% to 54%, including all the values in the range, for instance, 47.1%, 47.2%, 47.3%, 47.4% and so on and so forth.

In some embodiments of the present disclosure, the primer composition has viscosity ranging from about 140 cps to 160 cps, including all the values in the range, for instance, 141 cps, 142 cps, 143 cps, 144 cps and so on and so forth. In embodiment, viscosity of the primer composition is maintained in range of about 140 cps to 160 cps by the solvent, such a demineralized water present in the composition.

The inventors have identified that combination of the resin selected from a group comprising grated epoxy amine resin, grated epoxy ester resin and a combination thereof, the defoaming agent, the wetting agent, and the solvent, employed in the primer composition provides for improved coating properties, such as improved corrosion resistance, improved film forming property, improved paintability property, fast curing and improved flexibility.

The primer composition of the present disclosure provides for improved coating properties, such as improved corrosion resistance, improved film forming property, improved paintability property, fast curing, and improved flexibility across all types of steel substrates. It is noted that conventionally available primer compositions which are suitable for Cold Rolled Close Annealed (CRCA) steel are not suitable for galvanized iron, hot rolled steel and galvannealed steel, respectively. However, the primer composition of the present disclosure is suitable for all types of steel substrates, such as Cold Rolled Close Annealed (CRCA) steel, galvanized iron, hot rolled steel and galvannealed steel and the primer composition of the present disclosure imparts improved coating properties to said steel substrates.

The primer composition of the present disclosure provides for improved coating properties to substrates, such as improved corrosion resistance, improved film forming property, improved paintability property, fast curing, and improved flexibility without any post treatment upon application of the primer composition.

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

In some embodiments of the present disclosure, the method of preparing the primer composition comprises:
i. mixing the resin with the defoaming agent and the wetting agent to obtain a mixture; and
ii. adding the solvent to the mixture and mixing to obtain the primer composition.

In some embodiments of the present disclosure, the method of preparing the primer composition comprises:
i. mixing about 80 wt.% to 95 wt.% of the resin with about 0.4 wt.% to 1 wt.% of the defoaming agent and about 0.4 wt.% to 1 wt.% of the wetting agent to obtain a mixture; and
ii. adding about 3 wt.% of the 20 wt.% of the solvent to the mixture and mixing to obtain the primer composition.

In some embodiments of the present disclosure, the method of preparing the primer composition comprises:
i. mixing about 80 wt.% to 95 wt.% of the grafted epoxy amine resin with about 0.4 wt.% to 1 wt.% of the defoaming agent and about 0.4 wt.% to about 1 wt.% of the wetting agent to obtain a mixture; and
ii. adding about 3 wt.% 20 wt.% of the solvent to the mixture and mixing to obtain the primer composition.

In some embodiments of the present disclosure, the method of preparing the primer composition comprises:
i. mixing about 80 wt.% to 95 wt.% of the grafted epoxy ester resin with about 0.4 wt.% to 1 wt.% of the defoaming agent and about 0.4 wt.% to about 1 wt.% of the wetting agent to obtain a mixture; and
ii. adding about 3 wt.% to 20 wt.% of the solvent to the mixture and mixing to obtain the primer composition.

In some embodiments of the present disclosure, the method of preparing the primer composition comprises:
i. mixing about 80 wt.% to 95 wt.% of the grafted epoxy amine resin and the grafted epoxy ester resin with about 0.4 wt.% to 1 wt.% of the defoaming agent and about 0.4 wt.% to about 1 wt.% of the wetting agent to obtain a mixture; and
ii. adding about 3 wt.% to 20 wt.% of the solvent to the mixture and mixing to obtain the primer composition.

In some embodiments of the present disclosure, the mixing of the resin with the defoaming agent and the wetting agent is carried out at a temperature ranging from about 20 ? to 40 ?, including all the values in the range for instance, 20.1 ?, 20.2 ?, 20.3 ?, 20.4 ? and so on and so forth. In an embodiment, the mixing is carried out for a duration ranging from about 15 minutes and 20 minutes, including all the values in the range for instance, 15.1 minutes, 15.2 minutes, 15.3 minutes, 15.4 minutes and so on and so forth. In an embodiment, the mixing is carried out at a speed ranging from about 600 RPM to 700 RPM, including all the values in the range, for instance, 601 RPM, 602 RPM, 603 RPM, 604 RPM and so on and so forth.

In some embodiments of the present disclosure, the mixing the mixture comprising resin, the defoaming agent and the wetting agent and the solvent is carried out at a temperature ranging from about 20 ? to 40 ?, including all the values in the range for instance, 20.1 ?, 20.2 ?, 20.3 ?, 20.4 ? and so on and so forth. In an embodiment, the mixing is carried out for a duration ranging from about 20 minutes to 30 minutes, including all the values in the range for instance, 20.1 minutes, 20.2 minutes, 20.3 minutes, 20.4 minutes and so on and so forth. In an embodiment, the mixing is carried out at a speed ranging from about 240 RPM to 300 RPM, including all the values in the range, for instance, 241 RPM, 242 RPM, 243 RPM, 244 RPM and so on and so forth.

In some embodiments of the present disclosure, the resin, diamino toluene sulfonic acid grafted epoxy amine is prepared by mixing epoxy amine compound with diamine toluene sulfonic acid. In an embodiment, the mixing is carried out at a temperature ranging from about 50 ? to 60 ?, including all the values in the range, for instance, 50.1 ?, 50.2 ?, 50.3 ?, 50.4 ? and so on and so forth. In an embodiment, the mixing is carried out for a duration ranging from about 10 minutes to 15 minutes, including all the values in the range, for instance, 10.1 minutes, 10.2 minutes, 10.3 minutes, 10.4 minutes and so on and so forth.

In some embodiments of the present disclosure, in the diamino toluene sulfonic acid grafted epoxy amine, the epoxy amine compound is in an amount ranging from about 80 wt.% to 95 wt.%, including all the values in the range, for instance, 80.1 wt.%, 80.2 wt.%, 80.3 wt.%, 80.4% and so on and so forth and the diamine toluene sulfonic acid is in an amount ranging from about 0.2 wt.% to 0.3 wt.%, including all the values in the range, for instance, 0.21 wt.%, 0.22 wt.%, 0.23 wt.%, 0.24 wt.% and so on and so forth. In an embodiment, the diamine toluene sulfonic acid contains about 20% active acid, which was doped into the epoxy amine compound for enabling fast curing.

In some embodiments of the present disclosure, the resin, amine blocked para toluene sulfonic acid grafted epoxy ester is prepared by mixing epoxy ester with amine blocked para toluene sulfonic acid. In an embodiment, the mixing is carried out at a temperature ranging from about 50 ? to 60 ?, including all the values in the range, for instance, 50.1 ?, 50.2 ?, 50.3 ?, 50.4 ? and so on and so forth. In an embodiment, the mixing is carried out for a duration ranging from about 10 minutes to 15 minutes, including all the values in the range, for instance, 10.1 minutes, 10.2 minutes, 10.3 minutes, 10.4 minutes and so on and so forth.

In some embodiments of the present disclosure, in the amine blocked para toluene sulfonic acid grafted epoxy ester, the epoxy ester is in an amount ranging from about 80 wt.% to 95 wt.%, including all the values in the range, for instance, 80.1 wt.%, 80.2 wt.%, 80.3 wt.%, 80.4% and so on and so forth and the amine blocked para toluene sulfonic acid is in an amount ranging from about 0.2 wt.% to 0.3 wt.%, including all the values in the range, for instance, 0.21 wt.%, 0.22 wt.%, 0.23 wt.%, 0.24 wt.% and so on and so forth. In an embodiment, the amine blocked para toluene sulfonic acid contains about 16 wt.% of ethanoic acid as neutralizing agent. In an embodiment, the amine blocked para toluene sulfonic acid contains about 20% of active acid, which was doped into the epoxy ester for enabling fast curing.

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

In some embodiments of the present disclosure, the article is coated with the primer composition described above.

In some embodiments of the present disclosure, the coating of the primer composition on the article has thickness ranging from about 0.5 µm to 0.7 µm, including all the values in the range, for instance, 0.51 µm, 0.52 µm, 0.53 µm, 0.54 µm and so on and so forth.

In some embodiments of the present disclosure, the coating of the primer composition has highest level of adhesion with the article. In an embodiment, the adhesion level is ASTM class of about 5B according to cross hatch adhesion test.

In some embodiments of the present disclosure, the article coated with the primer composition is resistant to corrosion for about 96 hours to 120 hours, including all the values in the range, for instance, 96.1 hours, 96.2 hours, 96.3 hours, 96.4 hours and so on and so forth, according to salt spray test.

In some embodiments of the present disclosure, the article is any metal and/or alloy.

In some embodiments of the present disclosure, the article is steel substrate.

In some embodiments of the present disclosure, the article includes but it is not limited to carbon steel, hot rolled steel, hot rolled steel, galvanized iron, galvannealed steel.

In some embodiments of the present disclosure, the article coated with the primer composition is painted with paint composition.

In some embodiments of the present disclosure, the article coated with the primer composition is painted with powder paint composition including but it is not limited to polyester paint, polyester with epoxy paint and epoxy paint. Figures 1a and 1b illustrates results of the bending test (conical mendral test) conducted on the coated article, which is painted, wherein it can be noted that there is no cracking and delamination of the paint. Further, figures 2a and 2b illustrates results of cross hatch adhesion test of the coated article which is painted, wherein it can be noted that there is no removal of paint from the article.

The present disclosure further relates to method of producing the article coated with the primer composition.

In some embodiments of the present disclosure, the method of producing the article coated with the primer composition comprises- coating the article with the primer composition, followed by curing to obtain the article comprising coating of the primer composition.

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

In some embodiments of the present disclosure, the curing is carried out at a temperature ranging from about 110 ? to 120 ?, including all the values in the range, for instance, 110.1 ?, 110.2?, 110.3 ?, 110.4 ? and so on and so forth. In an embodiment, the curing is carried out for a duration ranging from about 10 minutes to 15 minutes, including all the values in the range, for instance, 10.1 minutes, 10.2 minutes, 10.3 minutes, 10.4 minutes and so on and so forth.

In some embodiments of the present disclosure, the method of producing the article coated with the primer composition comprises coating the article with the primer composition by techniques including but it is not limited to spray coating, dip coating, roll coating and wiping method, followed by curing at a temperature ranging from about 110 ? to 120 ?, for a duration ranging from about 10 minutes to 15 minutes.

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

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

EXAMPLES
Example 1: Preparation of Primer Composition
About 90 wt.% of epoxy compound was stirred with about 0.2 wt.% of diamine toluene sulfonic acid in a vessel at a temperature of about 60 ? for about 15 minutes to obtain grafted epoxy amine resin. About 0.4 wt.% of mineral oil was added to the grafted epoxy amine resin while grinding. Further, about 0.5 wt.% of the wetting agent was added to obtain a mixture. To the mixture, about 9.7 wt.% of demineralized water was added to obtain the primer composition.
The obtained primer composition was subjected to viscosity measurement by B4 cup ford, and it was found 45 seconds, which is in the range of about 140 cps to 160 cps. The specific gravity of the composition was 1.05 and the non-volatile content in the composition was about 54%.

Example 2: Preparation of Primer Composition
About 85 wt.% of the epoxy ester was stirred with about 0.3 wt.% of amine blocked para toluene sulfonic acid for about 10 minutes at a temperature of about 70 ? to obtain grafted epoxy ester resin. About 0.5 wt.% of mineral spirit was added to the grafted epoxy ester resin while grinding. Further, about 0.6 wt.% of the wetting agent was added to obtain a mixture. To the mixture, about 13.6 wt.% of demineralized water was added to obtain the primer composition.
The obtained primer composition was subjected to viscosity measurement by B4 cup ford, and it was found 40 seconds, which is in the range of about 140 cps to 160 cps. The specific gravity of the composition was 1.04 and the non-volatile content in the composition was about 47%.

Example 3: Producing article coated with primer composition
The primer composition obtained under Example 1 was applied on steel substrate by roll coater, where the applicator roll speed was kept at about 20 mpm, transported roll speed was fixed at about 6 mpm and dipping roller speed was kept at about 8.3 mpm. The applied coating was cured at a temperature of about 120 ? for about 10 minutes in hot air oven.
Corrosion resistance and adherence of the coated steel substrate (article) was evaluated by salt spray test and cross hatch adhesion test. The article showed corrosion resistance of about 96 hours (according to salt spray test). Further, the article showed no peel off of the coating during cross hatch adhesion test and the adhesion level was found highest of 5B.

Further, the article coated with the primer composition was painted with three different powder paint coatings- i) polyester paint; ii) polyester with epoxy paint; and iii) epoxy paint. The painted article was subjected to bending test according to conical mendral and adherence test by cross hatch adhesion test. Figure 1a shows that there was no cracking and delamination of the paint found during conical mendral test and Figure 2a shows no removal of the paint during the cross hatch adhesion test.

Example 4: Producing article coated with primer composition
The primer composition obtained under Example 2 was applied on steel substrate by roll coater, where the applicator roll speed was kept at about 20 mpm, transported roll speed was fixed at about 6 mpm and dipping roller speed was kept at about 8.3 mpm. The applied coating was cured at a temperature of about 120 ? for about 10 minutes in hot air oven.
Corrosion resistance and adherence of the coated steel substrate (article) was evaluated by salt spray test and cross hatch adhesion test. The article showed corrosion resistance of about 96 hours (according to salt spray test). Further, the article showed no peel off of the coating during cross hatch adhesion test and the adhesion level was found highest of 5B.

Further, the article coated with the primer composition was painted with three different powder paint coatings- i) polyester paint; ii) polyester with epoxy paint; and iii) epoxy paint. The painted article was subjected to bending test according to conical mendral and adherence test by cross hatch adhesion test. Figure 1b shows that there was no cracking and delamination of the paint found during conical mendral test and Figure 2b shows no removal of the paint during the cross hatch adhesion test.

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

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

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

While considerable emphasis has been placed herein on the particular features of this disclosure, it will be appreciated that various modifications can be made, and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other modifications in the nature of the disclosure or the preferred embodiments will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.
, Claims:WE CLAIM:
1. A primer composition, comprising-
- resin selected from a group comprising grafted epoxy amine resin, grafted epoxy ester resin and a combination thereof;
- defoaming agent;
- wetting agent; and
- solvent.
2. The primer composition as claimed in claim 1, wherein the grafted epoxy amine resin is diamino toluene sulfonic acid grafted epoxy amine; and the grafted epoxy ester resin is amine blocked para toluene sulfonic acid epoxy ester.
3. The primer composition as claimed in claim 1, wherein the grafted epoxy amine resin comprises solvent, wherein the solvent is a combination of propylene glycol and polyethylene glycol in a ratio of about 2:1.
4. The primer composition as claimed in claim 1, wherein the defoaming agent is selected from a group comprising mineral oil, mineral spirit and a combination thereof.
5. The primer composition as claimed in claim 1, wherein the wetting agent is ionic solution of polyacrylic copolymer.
6. The primer composition as claimed in claim 1, wherein the solvent is demineralized water.
7. The primer composition as claimed in claim 1, wherein the resin is in an amount ranging from about 80 wt.% to 95 wt.%; wherein the defoaming agent is in an amount ranging from about 0.4 wt.% to 1 wt.%; wherein the wetting agent is in an amount ranging from about 0.4 wt.% to 1 wt.%; and wherein the solvent is in an amount ranging from about 3 wt.% to 20 wt.%.
8. The primer composition as claimed in claim 1, wherein the composition has pH ranging from about 6.8 to 7.2.
9. The primer composition as claimed in claim 1, wherein the composition has specific gravity ranging from about 0.95 to 1.05.
10. The primer composition as claimed in claim 1, wherein the composition has non-volatile matter content ranging from about 47% to 54%.
11. The primer composition as claimed in claim 1, wherein the composition has viscosity ranging from about 140 cps to 160 cps.
12. A method of preparing the primer composition as claimed in claim 1, wherein the method comprises-
i. mixing the resin with the defoaming agent and the wetting agent; and
ii. adding the solvent and mixing to obtain the primer composition.
13. The method as claimed in claim 12, wherein the mixing in step i) is carried at a speed ranging from about 600 RPM to 700 RPM, for a duration ranging from about 15 minutes to 20 minutes; and wherein the mixing is carried out at a temperature ranging from about 20 ? to 40 ?.
14. The method as claimed in claim 12, wherein the mixing in the step ii) is carried out at a speed ranging from about 240 RPM to 300 RPM, for a duration ranging from about 20 minutes to 30 minutes; and wherein the mixing is carried out a temperature ranging from about 20 ? to 40 ?.
15. The method as claimed in claim 12, wherein the resin is selected from a group comprising diamino toluene sulfonic acid grafted epoxy amine and amine blocked para toluene sulfonic acid epoxy ester.
16. The method as claimed in claim 15, wherein the resin, diamino toluene sulfonic acid grafted epoxy amine is prepared by mixing epoxy amine compound with diamine toluene sulfonic acid; wherein the mixing is carried out at a temperature ranging from about 50 ? to 60 ?, for a duration ranging from about 10 minutes to 15 minutes.
17. The method as claimed in claim 16, wherein the epoxy amine compound is in an amount ranging from about 80 wt.% to 95 wt.%; and wherein the diamine sulfonic acid is in an amount ranging from about 0.2 wt.% to 0.3 wt.%.
18. The method as claimed in claim 15, wherein the resin, amine blocked para toluene sulfonic acid grafted epoxy ester is prepared by mixing epoxy ester with amine blocked para toluene sulfonic acid; wherein the mixing is carried out at a temperature ranging from about 50 ? to 60 ?, for a duration ranging from about 10 minutes to 15 minutes.
19. The method as claimed in claim 18, wherein the epoxy ester is in an amount ranging from about 80 wt.% to 95 wt.%; and wherein the amine blocked para toluene sulfonic acid is in an amount ranging from about 0.2 wt.% to 0.3 wt.%.
20. An article coated with the primer composition as claimed in claim 1.
21. The article as claimed in claim 20, wherein the article is selected from a group comprising carbon steel, hot rolled steel sheet, hot rolled steel tube, galvanized iron and galvannealed steel sheet.
22. The article as claimed in claim 20, wherein the coating has dry film thickness ranging from about 0.5 to 0.7 µm.
23. The article as claimed in claim 20, wherein the coating of the primer composition has highest level of adhesion with the article, having ASTM class of about 5B, according to cross hatch adhesion test.
24. The article as claimed in claim 20, wherein the article is resistant to corrosion for about 96 hours to 120 hours, according to salt spray test.
25. A method of producing the article as claimed in claim 20, said method comprises coating the article with the primer composition as claimed in claim 1, followed by curing to obtain the article comprising the coating.
26. The method as claimed in claim 25, wherein the coating is carried out by technique selected from a group comprising spray coating, dip coating, roll coating, wiping method, and any combinations thereof.
27. The method as claimed in claim 26, wherein the curing is carried out at a temperature ranging from about 110 ? to 120 ?, for a duration ranging from about 10 minutes to 15 minutes.

Dated this 30th day of August 2022
Signature:
Name: Sridhar R
To: IN/PA No. 2598
Of K&S Partners, Bangalore
The Controller of Patents Agent for the Applicant
The Patent Office, at Kolkata