DESC:FIELD
The present disclosure relates to a coating composition and a process for its preparation. Particularly, the present disclosure relates to 1K coating composition.
DEFINITIONS
As used in the present disclosure, the following terms are generally intended to have the meaning as set forth below, except to the extent that the context in which they are used to indicates otherwise.
2K coating system: The term “2K coating system” refers to two component polyurethane solvent borne system. In 2K solvent borne polyurethane system, a polyisocyanate hardener is reacted with a medium containing a polyhydroxyl acrylic binder to form a blend. The blend is applied by conventional tools and the polymer network is developed after the crosslinking reaction is complete. The 2K system requires a hardener, a catalyst or an activator.
1K coating system: The term “1K coating system” refers to a “single-component” coating, requires a cross linker, and can be air dried or thermally cured. The 1K coatings have faster drying times than 2K system.
Hydrophobic surface: The term “Hydrophobic surface” refers to a property of a surface that repels water.
Oleophobic surface: The term “Oleophobic surface” refers to a property of a surface that repels oil.
Wettability: The term “Wettability” refers to the ability of a liquid phase to adhere to a solid surface. Wettability is measured in terms of contact angle. If the contact angle is greater than 90° then the wettability is poor i.e. the ability of the liquid to adhere to the solid surface is poor and if the contact angle is smaller than 90° then the ability of the liquid to adhere to the solid surface is good i.e. the ability of the liquid to adhere the solid surface is good.
Gardner color scale: The term “Gardner color scale” refers to a one dimensional scale. The scale is used to measure the color of the liquid. The Gardner color with a range of 1 to 18 (1 for light yellow and 18 for red) is used to evaluate the color of the liquid.
Gardner Viscometer: The term “Gardner viscometer” also known as “Gardner bubble viscometer” refers to a viscometer that is used to measure the viscosity of liquids/resins. The Gardener viscometers come in lettered tubes A5 to Z10 in four different tube sets covering viscosity ranges from 0.05 stokes to 1000 stokes.
B4 Ford cup Viscometer: The term “B4 Ford cup viscometer” refers to a flow cup viscometer that is used to measure the viscosity of paints, inks, and coatings. The viscosity is measured by placing a known amount of paints, inks, and coatings in the cup at a specific temperature followed by allowing it to flow through the orifice of the cup into a container placed at the bottom. The time required by the paint, ink, and coatings to efflux from the cup is measured.
Effective metal temperature (EMT): The term “effective metal temperature (EMT)” refers to the temperature and the time at which the coating composition is cured at the baking schedule on application over a substrate.
Epoxy equivalent weight (EEW): The term “epoxy equivalent weight” refers to the weight of epoxy resin (in grams) that is required to give 1 mole of epoxy groups.
BACKGROUND
The background information herein below relates to the present disclosure but is not necessarily prior art.
Domestic and industrial care appliances have a tendency to accumulate dirt and dust particles. Dust deposition on the appliances is due to the static electricity generated on the surface. Air contains significant amounts of moisture, dust particles and oily ingredients. Due to the presence of moisture, dust particles and oily ingredients in the air, the appliances start corroding from the edges. Moreover, the accumulation of dirt and dust particles on the appliances adversely affects the performance and durability of the appliances. To overcome the aforementioned problems, a coating is applied on the appliances for better cleanability. However, the conventional coating systems used are the two component (2K) coating system.
The two component coating systems are associated with the drawbacks such as difficult to use, limited workability time, challenges of adherences to different painted surfaces and compromise on certain performance properties such as gloss, hardness and the like.
Therefore, there is felt a need to provide a coating composition and a process for its preparation that can mitigate the drawbacks mentioned hereinabove or at least provides an alternative solution.
OBJECTS
Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows.
An object of the present disclosure is to ameliorate one or more problems of the background or to at least provide a useful alternative.
Another object of the present disclosure is to provide a coating composition.
Still another object of the present disclosure is to provide a 1K coating composition.
Yet another object of the present disclosure is to provide a 1K coating composition which imparts an ease to clean property.
Still another object of the present disclosure is to provide a coating composition which is easy to use.
Yet another object of the present disclosure is to provide a process for the preparation of a coating composition.
Still another object of the present disclosure is to provide a simple, economical, and environment friendly process for the preparation of a coating composition.
Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.
SUMMARY
In an aspect, the present disclosure relates to a coating composition. The composition comprises at least one polyhydroxylic acrylic resin, at least one first fluid medium, at least one crosslinking agent, at least one catalyst, at least one additive, and at least one second fluid medium.
In an embodiment of the present disclosure, the polyhydroxylic acrylic resin is present in an amount in the range of 30 mass% to 50 mass%; the first fluid medium is present in an amount in the range of 5 mass% to 10 mass%; the crosslinking agent is present in an amount in the range of 5 mass% to 20 mass%; the catalyst is present in an amount in the range of 1 mass% to 7 mass%; the additive is present in an amount in the range of 2 mass% to 10 mass%; and the second fluid medium is present in an amount in the range of 25 mass% to 35 mass%; wherein the mass% of each ingredient is with respect to total mass of the coating composition.
In an embodiment of the present disclosure, the first fluid medium is at least one selected from the group consisting of 2-ethoxyethyl acetate, butyl acetate, and methoxy propyl acetate.
In an embodiment of the present disclosure, the crosslinking agent is at least one selected from the group consisting of methylated monomeric melamine crosslinker, melamine formaldehyde resin, and methylated imino melamine crosslinker in iso-butanol.
In an embodiment of the present disclosure, the catalyst is at least one selected from the group consisting of amine blocked para-toluene sulfonic acid catalyst, dodecyl benzene sulfonic acid (DDBSA), and amine neutralized p-toluenesulfonic acid (p-TSA).
In an embodiment of the present disclosure, the additive is at least one selected from a slip additive and a resin; wherein the slip additive is at least one selected from polyether-modified polydimethylsiloxane and silicone-modified polyacrylate; and wherein the resin is bisphenol-A based epoxy resin.
In an embodiment of the present disclosure, the second fluid medium is at least one selected from 2-ethoxyethanol, and butanol.
In an embodiment of the present disclosure, the polyhydroxylic acrylic resin is a functional monomeric siloxane acrylate.
In an embodiment of the present disclosure, the polyhydroxylic acrylic resin is characterized by having:
a. hydroxyl value in the range of 90 to 110;
b. non-volatile matter at 150°C / 1 gm/ 1 hour in the range of 54 % to 58%; and
c. acid value on non-volatile matter is in the range of 6 mgKOH/gm to 10 mgKOH/gm.
In an embodiment of the present disclosure, the viscosity of the composition is in the range of 50 seconds to 65 seconds as measured by the B4 Ford cup viscometer at 30°C.
In an embodiment of the present disclosure, the mass ratio of the catalyst to the polyhydroxylic acrylic resin is in the range of 1:7 to 1:22.
In an embodiment of the present disclosure, the mass ratio of the crosslinking agent to the polyhydroxylic acrylic resin is in the range of 1:2 to 1:4.
In another aspect, the present disclosure provides a process for the preparation of a coating composition. The predetermined amount of the polyhydroxylic acrylic resin is mixed with a predetermined amount of a first fluid medium in a reaction vessel under stirring at a speed in a range of 500 rpm to 700 rpm for a time period in the range of 5 minutes to 15 minutes to form a first homogeneous mixture. Under continuous stirring of the first homogeneous mixture predetermined amounts of at least one additive, at least one second fluid medium, and at least one crosslinking agent are added to the first homogeneous mixture under stirring at a speed in a range of 500 rpm to 700 rpm for a time period in the range of 20 minutes to 40 minutes to form a second homogeneous mixture. While stirring the second homogeneous mixture, a predetermined amount of at least one catalyst is added to the second homogeneous mixture under stirring at a speed in a range of 500 rpm to 700 rpm for a time period in the range of 10 minutes to 30 minutes followed by filtering to obtain the coating composition.
In an embodiment of the present disclosure, the filtering is performed by using a nylon mesh in the range of 350 mesh to 450 mesh.
In an embodiment of the present disclosure, the filtration process is performed to remove any dust or minute insoluble particles present in the coating composition.
Still, in another aspect, the present disclosure provides a method for coating a substrate. The method comprises mixing the coating composition with a thinner in a predetermined ratio to obtain a mixture. The mixture is coated on a substrate at a temperature in the range of 25 °C to 35 °C, followed by baking at an effective metal temperature (EMT) in the range of 115°C/30 minutes to 125°C/30 minutes to obtain a film on the substrate.
In an embodiment of the present disclosure, the thinner is a polar solvent.
In an embodiment of the present disclosure, the polar solvent is at least one selected from the group consisting of butanol, isobutanol, diacetone alcohol, and ethanol.
In an embodiment of the present disclosure, the predetermined ratio of the thinner to the coating composition is in the range of 1:2 to 1:6.
In an embodiment of the present disclosure, the film is characterized by having:
• gloss at 60° in the range of 90 to 95, in accordance with ASTM D-523 standard;
• film thickness in the range of 15 µm to 20 µm in accordance with ASTM-D7091 standard; and
• film hardness in the range of H to 3H in accordance with ASTM 3363 standard by pencil test.
DETAILED DESCRIPTION
The present disclosure relates to a coating composition and a process for its preparation. Particularly, the present disclosure relates to 1K coating composition.
Embodiments are provided so as to thoroughly and fully convey the scope of the present disclosure to the person skilled in the art. Numerous details are set forth, relating to specific components, and methods, to provide a complete understanding of embodiments of the present disclosure. It will be apparent to the person skilled in the art that the details provided in the embodiments should not be construed to limit the scope of the present disclosure. In some embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.
The terminology used, in the present disclosure, is only for the purpose of explaining a particular embodiment and such terminology shall not be considered to limit the scope of the present disclosure. As used in the present disclosure, the forms "a,” "an," and "the" may be intended to include the plural forms as well, unless the context clearly suggests otherwise. The terms "comprises," "comprising," “including,” and “having,” are open ended transitional phrases and therefore specify the presence of stated features, integers, steps, operations, elements, modules, units and/or components, but do not forbid the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The particular order of steps disclosed in the method and process of the present disclosure is not to be construed as necessarily requiring their performance as described or illustrated. It is also to be understood that additional or alternative steps may be employed.
As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed elements.
The terms first, second, third, etc., should not be construed to limit the scope of the present disclosure as the aforementioned terms may be only used to distinguish one element, component, region, layer or section from another component, region, layer or section. Terms such as first, second, third etc., when used herein do not imply a specific sequence or order unless clearly suggested by the present disclosure.
Domestic and industrial care appliances have a tendency to accumulate dirt and dust particles. Dust deposition on the appliances is due to the static electricity generated on the surface. Air contains significant amount of moisture, dust particle and oily ingredients. Due to the presence of the moisture, dust particle and oily ingredients in the air, the appliances start corroding from the edges. Moreover, the accumulation of dirt and dust particles on the appliances, adversely affects the performance and durability of the appliances. To overcome the aforementioned problems, coating is applied on the appliances for better cleanability. However, the conventional coating systems used are the two component (2K) coating system.
The two component coating systems are associated with the drawbacks such as difficult to use, limited workability time, challenges of adherences to different painted surfaces and compromise on certain performance properties such as gloss, hardness and the like.
The present disclosure provides a coating composition and a process for its preparation. The coating composition of the present disclosure is 1K coating composition.
In an aspect, the present disclosure provides a coating composition. The coating composition comprises at least one polyhydroxylic acrylic resin, at least one first fluid medium, at least one crosslinking agent, at least one catalyst, at least one additive, and at least one second fluid medium.
In an embodiment of the present disclosure, the polyhydroxylic acrylic resin is present in an amount in the range of 30 mass% to 50 mass% with respect to the total mass of the coating composition.
In an embodiment of the present disclosure, the first fluid medium is present in an amount in the range of 5 mass% to 10 mass% with respect to the total mass of the coating composition.
In an embodiment of the present disclosure, the crosslinking agent is present in an amount in the range of 5 mass% to 20 mass% with respect to the total mass of the coating composition.
In an embodiment of the present disclosure, the catalyst is present in an amount in the range of 1 mass% to 7 mass% with respect to the total mass of the coating composition.
In an embodiment of the present disclosure, the additive is present in an amount in the range of 2 mass% to 10 mass% with respect to the total mass of the coating composition.
In an embodiment of the present disclosure, the second fluid medium is present in an amount in the range of 25 mass% to 35 mass% with respect to the total mass of the coating composition.
In an embodiment of the present disclosure, the first fluid medium is at least one selected from the group consisting of 2-ethoxyethyl acetate, butyl acetate, and methoxy propyl acetate.
In an embodiment of the present disclosure, the crosslinking agent is at least one selected from the group consisting of methylated monomeric melamine crosslinker, melamine formaldehyde resin, and methylated imino melamine crosslinker in isobutanol.
In an embodiment of the present disclosure, the catalyst is at least one selected from the group consisting of amine blocked para-toluene sulfonic acid catalyst, dodecyl benzene sulfonic acid (DDBSA), and amine neutralized p-toluenesulfonic acid (p-TSA).
In an embodiment of the present disclosure, the additive is at least one selected from a slip additive and a resin.
In an embodiment of the present disclosure, the slip additive is at least one selected from polyether-modified polydimethylsiloxane and silicone-modified polyacrylate.
In an embodiment of the present disclosure, the slip additive is present in an amount in the range of 1 mass% to 4 mass% with respect to the total mass of the coating composition.
In an embodiment of the present disclosure, the resin is bisphenol-A based epoxy resin.
In an embodiment of the present disclosure, the bisphenol-A based epoxy resin is a solid epoxy resin having an epoxy equivalent weight (EEW) in the range of 400 gm/eq to 800 gm/eq in accordance with ISO 3001/ASTM D-1652.
In an embodiment of the present disclosure, the resin is present in an amount in the range of 1 mass% to 6 mass% with respect to the total mass of the coating composition.
In an embodiment of the present disclosure, the second fluid medium is at least one selected from 2-ethoxyethanol, and butanol.
In an embodiment of the present disclosure, the polyhydroxylic acrylic resin is a functional monomeric siloxane acrylate.
In an embodiment of the present disclosure, the functional monomeric siloxane acrylate is methacryl functional silane monomer.
The functional monomeric siloxane acrylate is prepared by grafting a siloxane moiety in monomer through solution polymerization.
In an embodiment of the present disclosure, the monomer is at least one selected from the group consisting of styrene, butyl acrylate, methyl methacrylate, hydroxy methacrylate, hydroxyl ethyl acrylate, and acrylic acid.
In an embodiment of the present disclosure, the polyhydroxylic acrylic resin is characterized by having:
a) hydroxyl value in the range of 90 to 110 in accordance with ASTM D-1957 standard;
b) non-volatile matter at 150°C/1 gm/1 hour in the range of 54 % to 58% in accordance with ASTM D-1353 standard; and
c) acid value on non-volatile matter is in the range of 6 mgKOH/gm to 10 mgKOH/gm in accordance with ASTM D-974 standard.
The functional monomeric siloxane acrylate imparts easy to clean property in the coating composition.
In an embodiment of the present disclosure, the viscosity of the coating composition is in the range of 50 seconds to 65 seconds when measured by B4 Ford cup viscometer at 30 °C.
In an embodiment of the present disclosure, the mass ratio of the catalyst to the polyhydroxylic acrylic resin is in the range of 1:7 to 1:22.
In an embodiment of the present disclosure, the mass ratio of the crosslinking agent to the polyhydroxylic acrylic resin is in the range of 1:2 to 1:4.
In another aspect, the present disclosure provides a process for the preparation of coating composition. The process comprises the following steps:
a) mixing in a reaction vessel a predetermined amount of a polyhydroxylic acrylic resin with a predetermined amount of first fluid medium under stirring at a speed in a range of 500 rpm to 700 rpm for a time period in the range of 5 minutes to 15 minutes to form a first homogeneous mixture;
b) continuing stirring of the first homogeneous mixture and adding predetermined amounts of at least one additive, at least one second fluid medium, and at least one crosslinking agent to the first homogeneous mixture under stirring at a speed in a range of 500 rpm to 700 rpm for a time period in the range of 20 minutes to 40 minutes to form a second homogeneous mixture; and
c) continuing stirring of the second homogeneous mixture and adding a predetermined amount of at least one catalyst to the second homogeneous mixture under stirring at 500 rpm to 700 rpm for a time period in the range of 10 minutes to 30 minutes followed by filtering to obtain the coating composition.
The process is described in detail as follows.
In a first step, predetermined amounts of the polyhydroxylic acrylic resin is mixed with a predetermined amount of a first fluid medium in a reaction vessel under stirring at a speed in a range of 500 rpm to 700 rpm for a time period in the range of 5 minutes to 15 minutes to form a first homogeneous mixture.
In an embodiment of the present disclosure, the predetermined amount of polyhydroxylic acrylic resin is in the range of 30 mass% to 50 mass% with respect to the total mass of the coating composition.
In an embodiment of the present disclosure, the first fluid medium is at least one selected from the group consisting of 2-ethoxyethyl acetate, butyl acetate, and methoxy propyl acetate.
In an embodiment of the present disclosure, the predetermined amount of the first fluid medium is in the range of 5 mass% to 10 mass% with respect to the total mass of the coating composition.
In an embodiment of the present disclosure, the reaction vessel is selected from a stainless steel reaction vessel and a mild steel reaction vessel (hopper).
In a second step, continuing the stirring of first homogeneous mixture, predetermined amounts of at least one additive, at least one second fluid medium and at least one crosslinking agent are added to the first homogeneous mixture under stirring at a speed in a range of 500 rpm to 700 rpm for a time period in the range of 20 minutes to 40 minutes to form a second homogeneous mixture.
In an embodiment of the present disclosure, the predetermined amount of additive is in the range of 2 mass% to 10 mass% with respect to the total mass of the coating composition.
In an embodiment of the present disclosure, the additive is at least one selected from a slip additive and a resin.
In an embodiment of the present disclosure, the slip additive is present in the range of 1 mass% to 4 mass% with respect to the total mass of the coating composition.
In an embodiment of the present disclosure, the slip additive is at least one selected from polyether-modified polydimethylsiloxane and silicone-modified polyacrylate.
Polyether-modified polydimethylsiloxane provides a reduction in the surface tension of the coating composition. It particularly improves substrate wetting and avoids cratering. Further, it increases the surface slip and gloss.
Silicone-modified polyacrylate solution (OH-functional) increases the hydrophobic and oleophobic properties of the coating composition which can significantly improve the water and oil-repelling behavior. Moreover, it helps in reduced dirt adhesion with simultaneously increased easy-to-clean effect. Further, the silicone-modified polyacrylate (OH-functional) increases substrate wetting, leveling, surface slip, water resistance (blush resistance), anti-blocking properties, and weather resistance.
In an embodiment of the present disclosure, the resin is present in the range of 1 mass% to 6 mass% with respect to the total mass of the coating composition.
In an embodiment of the present disclosure, the resin is bisphenol-A based epoxy resin.
In an embodiment of the present disclosure, the resin is Bisphenol-A based epoxy resin in 75% xylene.
Bisphenol-A based epoxy resin imparts chemical resistance to the coating composition of the present disclosure.
In an embodiment of the present disclosure, the crosslinking agent is at least one selected from the group consisting of methylated monomeric melamine crosslinker, melamine formaldehyde resin, and methylated imino melamine crosslinker in isobutanol.
In an embodiment of the present disclosure, the predetermined amount of the crosslinking agent is in the range of 5 mass% to 20 mass% with respect to the total mass of the coating composition.
Methylated monomeric melamine cross-linker contains mainly methoxymethyl functional sites making it an e?ective cross-linker for backbone polymer resins containing hydroxyl groups. Its high amount of monomer content and low tendency to self-condense, result in coated films with high ?exibility and formability.
Methylated imino melamine crosslinker in isobutanol is reactive and has a tendency towards self-condensation providing films/coatings with very good hardness, gloss, chemical resistance, and outdoor durability. It is suitable for a wide range of baking applications, such as coil and can coating formulations, automotive primers, topcoats, and general industrial coatings.
In an embodiment of the present disclosure, the second fluid medium is at least one selected from 2-ethoxyethanol, and butanol.
In an embodiment of the present disclosure, the predetermined amount of the second fluid medium is in the range of 25 mass% to 35 mass% with respect to the total mass of the coating composition.
In a third step, continuing the stirring of the second homogeneous mixture, a predetermined amount of at least one catalyst is added to the second homogeneous mixture under stirring at a speed in the range of 500 rpm to 700 rpm for a time period in the range of 10 minutes to 30 minutes followed by filtering to obtain the coating composition.
In an embodiment of the present disclosure, the catalyst is at least one selected from the group consisting of amine blocked para-toluene sulfonic acid catalyst, dodecyl benzene sulfonic acid (DDBSA), and amine neutralized p-toluenesulfonic acid (p-TSA).
In an embodiment of the present disclosure, the predetermined amount of the catalyst is in the range of 1 mass% to 7 mass% with respect to the total mass of the coating composition.
Amine blocked para-toluene sulfonic acid catalyst provides a fast response to curing. It has excellent stability in waterborne and fluid medium borne systems. It minimizes the film's wrinkling.
Amine neutralized p-toluenesulfonic acid (p-TSA) provides excellent cure response and stable viscosity. Further, it provides exterior durability to the cured films.
In another aspect, the present disclosure provides a method for coating a substrate. The method comprises the steps of:
(a) mixing the coating composition with at least one thinner in a predetermined ratio to obtain a mixture; and
(b) coating the mixture on a substrate at a temperature in the range of 25°C to 35°C, followed by baking at an effective metal temperature (EMT) in the range of 115°C/30 minutes to 125°C/30 minutes to obtain a film on the substrate.
The process is described in detail.
In the first step, the coating composition is mixed with a thinner in a predetermined ratio to obtain a mixture.
In an embodiment of the present disclosure, the thinner is a polar solvent.
In an embodiment of the present disclosure, the polar solvent is at least one selected from the group consisting of butanol, isobutanol, diacetone alcohol, and ethanol.
In an embodiment of the present disclosure, the predetermined ratio of the thinner to the coating composition is in the range of 1:2 to 1:6.
In the second step, the mixture is coated on a substrate at a temperature in the range of 25°C to 35°C (room temperature), followed by baking at an effective metal temperature (EMT) in the range of 115°C/30 minutes to 125°C/30 minutes to obtain a film on the substrate.
In an embodiment of the present disclosure, the substrate is selected from the group consisting of a metal substrate, a pretreated mild steel substrate, and a painted basecoat panel. In an embodiment of the present disclosure, the film coated on the substrate is characterized by having:
• gloss at 60° in the range of 90 to 95, in accordance with ASTM D523 standard;
• film thickness in the range of 15µm to 20 µm in accordance with ASTM D 7091 standard; and
• film hardness in the range of H to 3H in accordance with ASTM 3363 standard by pencil test.
The coating composition of the present disclosure is a 1K coating composition that imparts ease to clean property.
The foregoing description of the embodiments has been provided for purposes of illustration and not intended to limit the scope of the present disclosure. Individual components of a particular embodiment are generally not limited to that particular embodiment but are interchangeable. Such variations are not to be regarded as a departure from the present disclosure, and all such modifications are considered to be within the scope of the present disclosure.
The present disclosure is further described in light of the following experiments which are set forth for illustration purpose only and not to be construed for limiting the scope of the disclosure. The following experiments can be scaled up to industrial/commercial scale and the results obtained can be extrapolated to industrial scale.
Experimental details:
Example 1: Process for the preparation of coating composition in accordance with the present disclosure.
39.5 gm of polyhydroxylic acrylic resin (please refer to example 1 in Table 3) was mixed with 8.5 gm of 2-ethoxyethyl acetate (first fluid medium) in a reactor under stirring at 600 rpm for 10 minutes to form a first homogeneous mixture. Maintaining the stirring of the first homogeneous mixture, 0.2 gm of polyether-modified polydimethylsiloxane (slip additive), 1.5 gm of a silicone-modified polyacrylate (slip additive), 3.5 gm of bisphenol-A based epoxy resin in 75% xylene (resin) and 29.8 gm of butanol (second fluid medium), 13.5 gm of methylated monomeric melamine cross-linker (crosslinking agent) were added to the first homogeneous mixture under stirring at a speed of 600 rpm for 30 minutes to form a second homogeneous mixture. Maintaining the stirring of the second homogeneous mixture, 2 gm of amine blocked para-toluene sulfonic acid catalyst and 1.5 gm of dodecyl benzene sulfonic acid (catalyst) were added to the second homogeneous mixture under stirring at 600 rpm for 20 minutes followed by filtering through a 400 nylon mesh to obtain the coating composition.

Example 2:
The coating composition was prepared in a similar manner as example 1 except the proportion and ingredients were varied.
Table 1 illustrates the coating composition of example 1 and example 2 prepared in accordance with the present disclosure and the comparative examples.
Sr. No Ingredients
(mass %) Example
1 Example
2 Comparative example 1 Comparative example 2 Comparative example 3
1. polyhydroxylic acrylic resin 39.5 39.5 39.5 39.5 39.5
2. first fluid medium 2-ethoxyethyl acetate 8.5 8.5 32 32 32
3. crosslinking agent methylated monomeric melamine cross-linker 13.5 -- 15.5 15.5 15.5
methylated imino melamine cross-linker in iso-butanol -- 16 -- -- --
4. catalyst amine blocked para-toluene sulfonic acid catalyst 2 -- -- 0.5 0.2
Dodecyl benzene sulfonic acid 1.5 -- 1.8 -- --
amine neutralized p-toluenesulfonic acid (p-TSA) -- 2 -- -- --
5. additive slip additive polyether-modified polydimethylsiloxane 0.2 0.2 0.2 0.2 0.2
silicone-modified polyacrylate 1.5 1.5 -- -- --
resin bisphenol-A based epoxy resin 3.5 3.5 3.5 3.5 3.5
6. second
fluid medium 2-ethoxyethanol -- -- 5 6.5 6.8
Butanol 29.8 28.8 2.5 2.3 2.3

Example 3: Method for coating a substrate with the coating composition in accordance with the present disclosure.
25 ml of butanol (thinner) was mixed with 100 ml of coating composition obtained in example 1 or example 2 to obtain a mixture. The mixture was coated on a metallic substrate by spraying at 25 °C (room temperature) followed by baking at an effective metal temperature (EMT) of 120°C/30 minutes to obtain a film on the substrate.
Table 2 illustrates the baking temperature of the coating composition prepared in accordance with the present disclosure and the comparative examples.
Sr. No Examples Baking at an effective metal temperature (EMT)
1. Example 1 120°C for 30min
2. Example 2 120°C for 30min
3. Comparative example 1 140°C for 30min
4. Comparative example 2 140°C for 30min
5. Comparative example 3 140°C for 30min

From table 2 it is evident that the coating composition of the present disclosure requires a lower baking effective metal temperature (EMT) than the baking effective metal temperature (EMT) of the coating compositions of the comparative examples. It indicates that the coating composition of the present disclosure is an energy saving coating composition as compared to the coating composition of the comparative examples.
Characterization:
The characteristics of the polyhydroxylic acrylic resin and the coating composition are evaluated. The details are provided below.
(a) Characterization of the polyhydroxylic acrylic resin used in the coating composition of the present disclosure and the comparative examples:
The polyhydroxylic acrylic resin used in example 1 and example 2, for the preparation of the coating composition in accordance with the present disclosure was subjected to characterization. The characteristics are provided in Table 3 below.
Table 3 demonstrates the characteristics of the polyhydroxylic acrylic resin of example 1 and example 2 used in the present disclosure and the comparative examples.
Sr. No Examples Hydroxyl value Colour (Gardner colour scale) Clarity Visual Viscosity at 25 °C (Gardner viscometer) NVM (150°C / 1 gm/ 1 Hour) Acid Value on NVM mgKOH/gm
1. Example 1 101 0 to 1 Clear Z2 (3600 cps) 56.89 7.12
2. Example 2 101 0 to 1 Clear Z2Z3 (4100cps) 56.89 7.12
3. Comparative example 1 125 0 to 1 Clear V+ (9 00cps) 54.44 0.65
4. Comparative example 2 127 0 to 1 Clear X+ (1400 cps) 54.61 0.65
5. Comparative example 3 123 0 to 1 Clear Z1+ (2900 cps) 55.45 6.91

From Table 3 it is observed that the NVM (150°C/1gm/1 hour) of example 1 and example 2 was higher as compared to the comparative examples. Further, the acid value on NVM mgKOH/gm of the polyhydroxylic acrylic resin is also higher as compared to the comparative examples.

(b) Characterization of the coating composition prepared in accordance with the present disclosure and the comparative examples:
The coating composition of example 1 and example 2, prepared in accordance with the present disclosure, and the comparative examples were subjected to characterization.
The viscosity of the coating composition was measured using the B4 Ford Cup viscometer according to ASTM-D 803 standard.
Table 4 demonstrates the characteristics of the coating composition of example 1 and example 2 prepared in accordance with the present disclosure and the comparative examples.
Sr. No Examples Appearance Viscosity by B4 Ford cup viscometer at 30 °C
(seconds)
1. Example 1 Clear liquid 52
2. Example 2 Clear liquid 52
3. Comparative example 1 Clear liquid 53
. Comparative example 2 Clear liquid 53
5. Comparative example 3 Clear liquid 54

From Table 4 it is evident that the coating composition of the present disclosure has a lower viscosity than the viscosity of the coating compositions of the comparative examples. The lower viscosity helps in the ease of application of the coating composition.

(c) Characterization of the film obtained by applying the coating composition prepared in accordance with the present disclosure and the comparative examples:
The film obtained in example 3 was subjected to characterization such as dry film thickness, appearance, and finish.
The dry film thickness was measured by using a thickness gauge according to ASTM D 7091 standard.
Table 5 illustrates the characterization of the film obtained by applying the coating composition prepared in accordance with the present disclosure and the comparative examples.
Sr. No Examples Dry film thickness Appearance Finish
1. Example 1 15µm to 18µm Glossy Smooth
2. Example 2 15µm to 18µm Glossy Smooth
3. Comparative example 1 25µm to 30µm Glossy Smooth
4. Comparative example 2 25µm to 30µm Glossy Smooth
5. Comparative example 3 25µm to 30µm Glossy Smooth

From Table 5 it is observed that the dry film thickness of the film obtained by applying the coating composition of the present disclosure i.e. example 1 and example 2 on the substrate is in the range of 15µm to 18µm which is lower than the dry film thickness of the film obtained by applying the coating composition of the comparative examples. Additionally, based on the data in Table 5, it is observed that even with a reduced dry film thickness, the desired gloss and performance test outcomes are successfully achieved.
Mechanical Properties of the film:
The film obtained in Example 3 was subjected to evaluation of mechanical properties.
The adhesion test was performed according to ASTM D 3359 standard. The film hardness test was performed according to ASTM D3363 standard. The gloss at 60° was measured by a glossmeter according to ASTM D 523 standard.
The easy to clean test was performed by applying marker stain on the film followed by drying for 1 min to obtain a stained film. The stained film was rubbed with a muslin cloth. If stains are not visible, then the film was considered to be passed in the ease to clean test.
Table 6 illustrates the mechanical properties of the film obtained by applying the coating composition prepared in accordance with the present disclosure and the comparative examples.
Sr. No Examples Adhesion test Film Hardness Gloss at 60° Ease to clean test
1. Example 1 Pass 2H 92 Excellent
2. Example 2 Pass 2H 92 Excellent
3. Comparative example 1 Fail 3H 90 Pass
4. Comparative example 2 Fail 3H 91 Pass
5. Comparative example 3 Pass 2H 91 Pass
From Table 6 it was evident that the film obtained by applying the coating composition of the present disclosure has a higher gloss of 92 at 60° as compared to the film obtained by the coating composition of the comparative examples. Further, the film obtained by applying the coating composition of the present disclosure has excellent ease to clean properties as compared to the film obtained by the coating composition of the comparative examples. Furthermore, from the adhesion test it is observed that the film obtained by applying the coating composition of the present disclosure passes the adhesion test. It indicates that the film obtained by applying the coating composition of the present disclosure have enhanced adhesion properties as compared to the compositions of comparative examples.
TECHNICAL ADVANCEMENTS
The present disclosure described herein above has several technical advantages including, but not limited to, the realization of a coating composition that:
• is easy to handle;
• is easy to use;
• is easy to clean;
• requires lower effective metal temperature (EMT) for baking; and
• is a 1k coating system.
and a process for the preparation of a coating composition that;
• is simple and economical.
Throughout this specification, the word “comprise”, or variations such as “comprises” or “comprising, will be understood to imply the inclusion of a stated element, integer or step,” or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
The use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the invention to achieve one or more of the desired objects or results. While certain embodiments of the inventions have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Variations or modifications to the formulation of this invention, within the scope of the invention, may occur to those skilled in the art upon reviewing the disclosure herein. Such variations or modifications are well within the spirit of this invention.
The numerical values given for various physical parameters, dimensions and quantities are only approximate values and it is envisaged that the values higher than the numerical value assigned to the physical parameters, dimensions and quantities fall within the scope of the invention unless there is a statement in the specification to the contrary.
While considerable emphasis has been placed herein on the specific features of the preferred embodiment, it will be appreciated that many additional features can be added and that many changes can be made in the preferred embodiment without departing from the principles of the disclosure. These and other changes in the preferred embodiment of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation. ,CLAIMS:WE CLAIM:
1. A coating composition, said composition comprises:
a) at least one polyhydroxylic acrylic resin;
b) at least one first fluid medium;
c) at least one crosslinking agent;
d) at least one catalyst;
e) at least one additive; and
f) at least one second fluid medium.
2. The composition as claimed in claim 1, wherein
a) said polyhydroxylic acrylic resin is present in an amount in the range of 30 mass% to 50 mass%;
b) said first fluid medium is present in an amount in the range of 5 mass% to 10 mass%;
c) said crosslinking agent is present in an amount in the range of 5 mass% to 20 mass%;
d) said catalyst is present in an amount in the range of 1 mass% to 7 mass%;
e) said additive is present in an amount in the range of 2 mass% to 10 mass%; and
f) said second fluid medium is present in an amount in the range of 25 mass% to 35 mass%;
wherein said mass% of each ingredient is with respect to the total mass of the coating composition.
3. The composition as claimed in claim 1, wherein
i) said first fluid medium is at least one selected from the group consisting of 2-ethoxyethyl acetate, butyl acetate, and methoxy propyl acetate;
ii) said crosslinking agent is at least one selected from the group consisting of methylated monomeric melamine crosslinker, melamine formaldehyde resin, and methylated imino melamine crosslinker in isobutanol;
iii) said catalyst is at least one selected from the group consisting of amine blocked para-toluene sulfonic acid catalyst, dodecyl benzene sulfonic acid (DDBSA) and amine neutralized p-toluenesulfonic acid (p-TSA);
iv) said additive is at least one selected from a slip additive and a resin wherein said slip additive is at least one selected from polyether-modified polydimethylsiloxane and silicone-modified polyacrylate; and wherein said resin is bisphenol-A based epoxy resin; and
v) said second fluid medium is at least one selected from 2-ethoxyethanol, and butanol.
4. The composition as claimed in claim 1, wherein said polyhydroxylic acrylic resin is a functional monomeric siloxane acrylate.
5. The composition as claimed in claim 1, wherein said polyhydroxylic acrylic resin is characterized by having:
a) hydroxyl value in the range of 90 to 110;
b) non-volatile matter at 150°C / 1 gm/ 1 hour in the range of 54 % to 58%; and
c) acid value on non-volatile matter in the range of 6 mgKOH/gm to 10 mgKOH/gm.
6. The composition as claimed in claim 1, wherein the viscosity of said coating composition is in the range of 50 seconds to 65 seconds as measured by B4 Ford cup viscometer at 30 °C.
7. The composition as claimed in claim 1, wherein the mass ratio of said catalyst to said polyhydroxylic acrylic resin is in the range of 1:7 to 1:22.
8. The composition as claimed in claim 1, wherein the mass ratio of said crosslinking agent to said polyhydroxylic acrylic resin is in the range of 1:2 to 1:4.
9. A process for preparation of a coating composition, said process comprising the following steps:
a) mixing in a reaction vessel a predetermined amount of a polyhydroxylic acrylic resin with a first fluid medium under stirring at a speed in a range of 500 rpm to 700 rpm for a time period in the range of 5 minutes to 15 minutes to form a first homogeneous mixture;
b) continuing stirring said first homogeneous mixture and adding predetermined amounts of at least one additive, at least one second fluid medium and at least one crosslinking agent to said first homogeneous mixture under stirring at a speed in a range of 500 rpm to 700 rpm for a time period in the range of 20 minutes to 40 minutes to form a second homogeneous mixture; and
c) continuing stirring said second homogeneous mixture and adding a predetermined amount of at least one catalyst to said second homogeneous mixture under stirring at a speed in a range of 500 rpm to 700 rpm for a time period in the range of 10 minutes to 30 minutes followed by filtering to obtain said coating composition.
10. The process as claimed in claim 9, wherein said filtering is performed by using a nylon mesh in the range of 350 mesh to 450 mesh.
11. A method for coating a substrate, said method comprises the following steps:
(a) mixing said coating composition as claimed in claim 1 with at least one thinner in a predetermined ratio to obtain a mixture; and
(b) coating said mixture on a substrate at a temperature in the range of 25 °C to 35°C, followed by baking at an effective metal temperature (EMT) in the range of 115°C/30 minutes to 125°C/30 minutes to obtain a film on the substrate.
12. The method as claimed in claim 11, wherein said thinner is a polar solvent.
13. The method as claimed in claim 12, wherein said polar solvent is at least one selected from the group consisting of butanol, isobutanol, diacetone alcohol, and ethanol.
14. The method as claimed in claim 11, wherein said predetermined ratio of said thinner to said coating composition is in the range of 1:2 to 1:6.
15. The method as claimed in claim 11, wherein said film is characterized by having:
i) gloss at 60° in the range of 90 to 95;
ii) film thickness in the range of 15 µm to 20 µm; and
iii) film hardness in the range of H to 3H in accordance with ASTM 3363 standard by pencil test.

Dated this 05th day of September, 2023

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

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