DESC:FIELD
The present disclosure relates to a coating composition and a process for its preparation.
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 it is used indicates otherwise.
Organic polysilazane refers to a type of polysilazane in which at least one organic substituent is bound to the silicon atom.
Solar factor refers to the amount of heat that is transmitted through the glass.
BACKGROUND
The background information herein below relates to the present disclosure but is not necessarily prior art.
Glass is increasingly used in building construction due to various properties such as aesthetics, transparency, and durability. However, glass picks up dirt and becomes dull over time that requires operational expenditure for regular cleaning. Further, the transmission of heat through the glass, results in the greenhouse effect leading to more energy consumption. Furthermore, an installed glass facade doesn’t give scope for decor and playing with colors.
Conventionally, the problem of dirt pick up on the glass is addressed by applying nano titania based photocatalytic coatings on the glass surface by vapor deposition under vacuum at an elevated temperature; and by applying hydrophilic and hydrophobic coating on the exterior of the glass.
Further, the problem of heat transfer through the glass is addressed either by installing tinted glasses which involve the installation of an entirely new glass façade and create a heavy tint changing the appearance of the glass or by applying sun control films on the interior/exterior of the glass. However, the sun control films have adhesion and peeling problems on the exterior of the glass. Still further, the problem of heat control through the glass can be overcome by coating containing infrared blocking pigments on the interior of the glass. However, the coating containing infrared blocking pigments cannot be applied to the exterior of the glass due to poor dirt pickup resistance.
There is no single solution that provides both heat reduction and dirt pickup resistance on pre-installed glass substrates with good adhesion properties and good mechanical properties.
Therefore, there is felt a need for a coating composition that can mitigate the drawbacks mentioned hereinabove or at least provide 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 prior art or to at least provide a useful alternative.
Another object of the present disclosure is to provide a coating composition.
Yet another object of the present disclosure is to provide a coating composition that can offer various colors to the installed glass, comparatively better adhesion property on glass and can be applied by conventional means of ragging, brushing, wiping, rolling, and spraying.
Still another object of the present disclosure is to provide a coating composition that has good adhesion properties and good mechanical properties.
Yet another object of the present disclosure is to provide a coating composition which addresses both the problems such as dirt pick up resistance and heat reduction.
Still another object of the present disclosure is to provide a coating composition that cures at ambient temperature.
Yet another object of the present disclosure is to provide a 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
The present disclosure relates to a coating composition and a process for its preparation. In an aspect, the coating composition comprises a first component comprising (i) a polymeric polyol in an amount in the range of 2 mass% to 5 mass% w.r.t the total mass of the first component; (ii) inorganic nanoparticles in an amount in the range of 1 mass% to 4 mass% w.r.t the total mass of the first component; (iii) a rheology modifier in an amount in the range of 1 mass% to 4 mass% w.r.t the total mass of the first component; (iv) a dispersing agent in an amount in the range of 1 mass% to 5 mass% w.r.t the total mass of the first component; and (v) a first fluid medium in an amount in the range of 80 mass% to 90 mass% w.r.t the total mass of the first component; and a second component comprising (i) an organic polysilazane in an amount in the range of 10 mass% to 20 mass% w.r.t the total mass of the second component; (ii) a second fluid medium in an amount in the range of 80 mass% to 90 mass% w.r.t the total mass of the second component; wherein the first component and the second component are mixed in a mass ratio in the range of 20:80 to 50:50 before application to obtain the coating composition.
In another aspect, the process for the preparation of the coating composition comprises blending a first predetermined amount of first fluid medium, a rheology modifier at a speed in the range of 30 rpm to 80 rpm for a first predetermined time period to obtain a first mixture. The first mixture is blended with a dispersing agent, inorganic nanoparticles at a speed in the range of 80 rpm to 120 rpm for second predetermined time period to obtain a second mixture. The so obtained second mixture is milled to obtain the third mixture having a particle size in the range of 10 nm to 200 nm. The third mixture is blended with a second predetermined amount of the first fluid medium and a polymeric polyol to obtain a first component. Separately, blending an organic polysilazane and a second fluid medium at a speed in the range of 30 rpm to 80 rpm for a third predetermined time period to obtain a second component. The first component and the second component are mixed before application to obtain the coating composition.
DETAILED DESCRIPTION
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.
Glass is increasingly used in building constructions due to various properties such as aesthetics, transparency, and durability. However, glass picks up dirt and becomes dull over a time, wherein it requires operational expenditure for regular cleaning. Further, the transmission of heat through the glass results, in the greenhouse effect leading to more energy consumption. Furthermore, the installed glass facade doesn’t give scope for decor and playing with colors.
Commercially available coating compositions have the drawbacks such as low dirt pickup resistance and low adhesion property on the exterior side of the glass; hence the coating with infrared blocking pigments cannot be applied on the exterior side of the glass. Further, the commercial coating composition does not exhibit better adhesion properties and mechanical properties when applied on already installed glass substrates.
The present disclosure provides a coating composition and a process for its preparation. Particularly, the present disclosure provides a coating composition suitable for various substrates and a process for its preparation.
The coating composition of the present disclosure provides both heat reduction as well as dirt pickup resistance on the interior and/or exterior side of the surface of the glass surface that has good adhesion properties and good mechanical properties.
In an aspect of the present disclosure, there is provided a two-component coating composition.
The coating composition comprises a first component comprising (i) a polymeric polyol in an amount in the range of 2 mass% to 5 mass% w.r.t the total mass of the first component; (ii) inorganic nanoparticles in an amount in the range of 1 mass% to 4 mass% w.r.t the total mass of the first component; (iii) a rheology modifier in an amount in the range of 1 mass% to 4 mass% w.r.t the total mass of the first component; (iv) a dispersing agent in an amount in the range of 1 mass% to 5 mass% w.r.t the total mass of the first component; (v) a first fluid medium in an amount in the range of 80 mass% to 90 mass% w.r.t the total mass of the first component; and a second component comprising (i) an organic polysilazane in an amount in the range of 10 mass% to 20 mass% w.r.t the total mass of the second component; (ii) a second fluid medium in an amount in the range of 80 mass% to 90 mass% w.r.t the total mass of the second component.
In an embodiment of the present disclosure, the first component and the second component are mixed in a mass ratio in the range of 20:80 to 50:50 before application to obtain the coating composition.
In an embodiment of the present disclosure, the polymeric polyol is at least one selected from the group consisting of polycarbonate polyol, polyester polyol, acrylic polyol, epoxy polyol, cellulosic polyol, polyether polyol, caprolactone based polyol, aldehyde resin-based polyol, ketonic resin-based polyol, and their dendrimers. In an exemplary embodiment of the present disclosure, the polymeric polyol is an acrylic polyol.
In an embodiment of the present disclosure, the polyol is characterized by having a hydroxyl value in the range of 80 mg KOH/g to 120 mg KOH/g and an acid value in the range of 4 mg KOH/g to 8 mg KOH/g. In an exemplary embodiment of the present disclosure, the acrylic polymer has a hydroxyl value of 100 mg KOH/g and an acid value of 6 mg KOH/g. The polymeric polyol has 50% solids.
In accordance with the present disclosure, the first component comprises at least one additive selected from a filler, a levelling agent, an anti-foaming agent, an adhesion promoter, and a surface modifying agent.
In an embodiment of the present disclosure, the filler is at least one selected from the group consisting of nanosilica, alumina, titania (titanium oxide), and zinc oxide. In an exemplary embodiment of the present disclosure, the filler is nanosilica. The fillers can modify the surface of the coating and improve the dirt pickup resistance of the coating. The filler is present in an amount in the range of 0.2 mass% to 1 mass% w.r.t the total mass of the first component.
In an embodiment of the present disclosure, the filler has a BET surface area in the range of 90 m2/g to 400 m2/g. In an exemplary embodiment of the present disclosure, the BET surface area of the nanosilica is 200 m2/g.
In an embodiment of the present disclosure, the levelling agent is at least one selected from the group consisting of silicone-free polyacrylate (TEGO FLOW 300), polyether siloxane polymer (TEGO FLOW 425), and silicone free solvent mixture of high boiling solvents (BYKETOL OK). In an exemplary embodiment of the present disclosure, the levelling agent is silicone-free polyacrylate (TEGO FLOW 300). The leveling agent is preferably added when the coating is to be applied by roller or spray technique. It is an optional component when the design is to be applied by ragging using microfiber cloth. The levelling agent is present in an amount in the range of 1 mass% to 4 mass% w.r.t the total mass of the first component.
In an embodiment of the present disclosure, the inorganic nanoparticles are at least one selected from the group consisting of silicon dioxide, titanium dioxide, zinc oxide, aluminum oxide, antimony tin oxide, indium tin oxide, cesium tungsten oxide, aluminum zinc oxide, graphene nanoparticles, graphene oxide, reduced graphene oxide, carbon nanofibers, single walled carbon nanotubes, multi-walled carbon nanotubes, and nanoclays. In an exemplary embodiment of the present disclosure, the doped metal oxide nanoparticles are indium tin oxide.
In an embodiment of the present disclosure, the particle size of the inorganic nanoparticles is in the range of 10 nm to 200 nm. In an exemplary embodiment of the present disclosure, the particle size of the inorganic nanoparticles is 100 nm.
In an embodiment of the present disclosure, the rheology modifier is at least one selected from the group consisting of ethyl cellulose, polyurea, polyamide, hydrogenated castor oil, organoclay, and fumed silica. In an exemplary embodiment of the present disclosure, the rheology modifier is ethyl cellulose.
In an embodiment of the present disclosure, the dispersing agent is at least one selected from the group consisting of TEGO DISPERSE 670, DISPERBYK 111, DISPERBYK 103, DISPERBYK 2055, and DISPERBYK 163 (copolymer with pigment affinic groups). In an exemplary embodiment of the present disclosure, the dispersing agent is TEGO DISPERSE 670.
In an embodiment of the present disclosure, the first fluid medium is at least one selected from the group consisting of ortho-xylene, methyl amyl ketone, butyl acetate, methyl isobutyl ketone, methoxy propyl acetate, and ethyl acetate. In an exemplary embodiment of the present disclosure, the first fluid medium is a mixture of ortho-xylene, methyl amyl ketone, and butyl acetate.
In an embodiment of the present disclosure, the anti-foaming agent is at least one selected from the group consisting of polymethylalkylsiloxane (BYK-085), a silicone-free solution of foam destroying substances (BYK A555, Efka PB 2020). The anti-foaming agent is preferably added when the coating is to be applied by roller or spray technique. It is an optional component when the design is to be applied by ragging using a microfiber cloth. The anti-foaming agent is present in an amount in the range of 0.01 mass% to 0.1 mass% w.r.t the total mass of the first component.
In an embodiment of the present disclosure, the adhesion promoter is at least one selected from the group consisting of 3-aminopropyltriethoxysilane, 3-glycidoxypropyltriethoxysilane, methyltrimethoxysilane, Dynasylan F 8261 (bifunctional silane possessing hydrolyzable inorganic ethoxysilyl groups and a fluoroalkyl chain). In an exemplary embodiment of the present disclosure, the adhesion promoter is Dynasylan F 8261. The adhesion promoter is present in an amount in the range of 0.01 mass% to 2 mass% w.r.t the total mass of the first component.
In an embodiment of the present disclosure, the surface modifying agent is alkyl silicate oligomer is at least one selected from the group consisting of methyl silicate oligomer (MKC MS56), and ethyl silicate oligomer. In an exemplary embodiment of the present disclosure, the surface modifying agent is MKC MS56. The surface modifying agent is present in an amount in the range of 0.5 mass% to 3 mass% w.r.t the total mass of the first component.
In an embodiment of the present disclosure, the organic polysilazane is at least one selected from the group consisting of Durazene 1500 slow cure (mixture of polymethyl(hydro)/polymethylsilazane and 3-aminopropyltriethoxysilane), Durazene 1500 Rapid cure, Durazene 1800, Durazene 2250, Durazene 2850, dimethyl disilazane, trimethyl disilazane, tetramethyl disilazane, pentamethyl disilazane, hexamethyl disilazane, octamethyl trisilazane, hexamethylcyclo-trisilazane, tetraethyltetramethylcyclo tetrasilazane, tetraphenyldimethyl disilazane, dipropyltetramethyl disilazane, dibutyltetramethyl disilazane, dihexyltetramethyl disilazane, dioctyltetramethyl disilazane, diphenyl tetramethyl disilazane, octamethylcyclo tetrasilazane, cyclosilazane, and fluorine-containing organic silazane compound. In an exemplary embodiment of the present disclosure, the organic polysilazane is Durazene 1500 slow cure.
In an embodiment of the present disclosure, the second fluid medium is at least one selected from the group consisting of ortho-xylene, methyl amyl ketone, ethyl acetate, butyl acetate, and methoxypropyl acetate. In an exemplary embodiment of the present disclosure, the second fluid medium is a mixture of ortho-xylene, and methyl amyl ketone.
In an embodiment of the present disclosure, the first component and second component are mixed in a mass ratio in the range of 20:80 to 50:50 before application to obtain the coating composition.
In an embodiment of the present disclosure, the coating composition is coated on a substrate selected from the group consisting of glass, metal, plastic, and concrete.

In an embodiment of the present disclosure, the substrate coated with the coating composition of the present disclosure is characterized by having
a. a visible light transmission in the range of 80% to 90%;
b. a water contact angle in the range of 40° to 110°;
c. a surface energy in the range of 15 mN/m to 60 mN/m; and
d. a solar factor in the range of 0.5 to 0.7;

In another aspect of the present disclosure, there is provided a process for the preparation of the coating composition.
The process is described in detail.
In a first step, a first predetermined amount of first fluid medium, a rheology modifier is blended at a speed in the range of 30 rpm to 80 rpm for a first predetermined time period to obtain a first mixture. In an exemplary embodiment of the present disclosure, the speed is 50 rpm.
In an embodiment of the present disclosure, the first fluid medium is at least one selected from the group consisting of ortho-xylene, methyl amyl ketone, butyl acetate, methyl isobutyl ketone, methoxy propyl acetate, and ethyl acetate. In an exemplary embodiment of the present disclosure, the first fluid medium is a mixture of ortho-xylene, methyl amyl ketone, and butyl acetate.
In an embodiment of the present disclosure, the rheology modifier is at least one selected from the group consisting of ethyl cellulose, polyurea, polyamide, hydrogenated castor oil, organoclay, and fumed silica. In an exemplary embodiment of the present disclosure, the rheology modifier is ethyl cellulose.
In an embodiment of the present disclosure, the first predetermined time period is in the range of 10 min to 60 min. In an exemplary embodiment of the present disclosure, the first predetermined time period is 20 min.
In an embodiment of the present disclosure, the first predetermined amount of the first fluid medium is in the range of 30 mass% to 40 mass% with respect to the total amount of the first fluid medium. In an exemplary embodiment of the present disclosure, the first predetermined amount of the first fluid medium is 36% with respect to the total amount of the first fluid medium.
At least one additive is added during the preparation of second mixture or third mixture to obtain the first component. The at least one additive is selected from a filler, a levelling agent, an anti-foaming agent, an adhesion promoter, and a surface modifying agent.
In a second step, a dispersing agent, inorganic nanoparticles are added to the first mixture and blended at a speed in the range of 80 rpm to 120 rpm for a second predetermined time period to obtain a second mixture. In an exemplary embodiment of the present disclosure, the speed is 100 rpm.
In an embodiment of the present disclosure, the dispersing agent is at least one selected from the group consisting of TEGO DISPERSE 670, DISPERBYK 111, DISPERBYK 103, DISPERBYK 2055, and DISPERBYK 163 (copolymer with pigment affinic groups). In an exemplary embodiment of the present disclosure, the dispersing agent is TEGO DISPERSE 670.
In an embodiment of the present disclosure, the filler is optionally added to the first mixture and is at least one selected from the group consisting of nanosilica, alumina, titania (titanium oxide), and zinc oxide. In an exemplary embodiment of the present disclosure, the filler is nanosilica. The fillers can modify the surface of the coating and improve the dirt pickup resistance of the coating. The filler is present in an amount in the range of 0.2 mass% to 1 mass% w.r.t the total mass of the first component.
In an embodiment of the present disclosure, the filler has a BET surface area in the range of 90 m2/g to 400 m2/g. In an exemplary embodiment of the present disclosure, the BET surface area of the nanosilica is 200 m2/g.
In an embodiment of the present disclosure, the inorganic nanoparticles are at least one selected from the group consisting of silicon dioxide, titanium dioxide, zinc oxide, aluminum oxide, antimony tin oxide, indium tin oxide, cesium tungsten oxide, aluminum zinc oxide, graphene nanoparticles, graphene oxide, reduced graphene oxide, carbon nanofibers, single walled carbon nanotubes, multi-walled carbon nanotubes, and nanoclays. In an exemplary embodiment of the present disclosure, the doped metal oxide nanoparticles are indium tin oxide.
In an embodiment of the present disclosure, the second predetermined time period is in the range of 20 min to 40 min. In an exemplary embodiment of the present disclosure, the first predetermined time period is 30 min.
In a third step, the second mixture is subjected to milling to obtain a third mixture with a particle size in the range of 10 nm to 200 nm. In an exemplary embodiment of the present disclosure, the particle size of the third mixture is 150 nm.
In an embodiment of the present disclosure, the adhesion promoter is optionally added to the second mixture and is at least one selected from the group consisting of 3-aminopropyltriethoxysilane, 3-glycidoxypropyltriethoxysilane, methyltrimethoxysilane, Dynasylan F 8261 (bifunctional silane possessing hydrolyzable inorganic ethoxysilyl groups and a fluoroalkyl chain). In an exemplary embodiment of the present disclosure, the adhesion promoter is Dynasylan F 8261. The adhesion promoter is present in an amount in the range of 0.01 mass% to 2 mass% w.r.t the total mass of the first component.
In an embodiment of the present disclosure, the surface modifying agent is optionally added to the second mixture and is alkyl silicate oligomer wherein the is alkyl silicate oligomer at least one selected from the group consisting of methyl silicate oligomer (MKC MS56), and ethyl silicate oligomer. In an exemplary embodiment of the present disclosure, the surface modifying agent is MKC MS56. The surface modifying agent is present in an amount in the range of 0.5 mass% to 3 mass% w.r.t the total mass of the first component.
In a fourth step, a second predetermined amount of the first fluid medium and a polymeric polyol are added to the third mixture and blended at a speed in the range of 30 rpm to 80 rpm for a time period in the range of 10 min to 60 min to obtain a first component. In an exemplary embodiment of the present disclosure, the speed is 50 rpm for 30 min.
In an embodiment of the present disclosure, the levelling agent is optionally added to the third mixture and is at least one selected from the group consisting of silicone-free polyacrylate (TEGO FLOW 300), polyether siloxane polymer (TEGO FLOW 425), and silicone free solvent mixture of high boiling solvents (BYKETOL OK). In an exemplary embodiment of the present disclosure, the levelling agent is silicone-free polyacrylate (TEGO FLOW 300). The leveling agent is preferably added when the coating is to be applied by roller or spray technique. It is an optional component when the design is to be applied by ragging using microfiber cloth. The levelling agent is present in an amount in the range of 1 mass% to 4 mass% w.r.t the total mass of the first component.
In an embodiment of the present disclosure, the anti-foaming agent is optionally added to the third mixture and is at least one selected from the group consisting of polymethylalkylsiloxane (BYK-085), a silicone-free solution of foam destroying substances (BYK A555, Efka PB 2020). The anti-foaming agent is preferably added when the coating is to be applied by roller or spray technique. It is an optional component when the design is to be applied by ragging using microfiber cloth. The anti-foaming agent is present in an amount in the range of 0.01 mass% to 0.1 mass% w.r.t the total mass of the first component.
In an embodiment of the present disclosure, the polymeric polyol is at least one selected from the group consisting of polycarbonate polyol, polyester polyol, acrylic polyol, epoxy polyol, cellulosic polyol, polyether polyol, caprolactone based polyol, aldehyde resin-based polyol, ketonic resin-based polyol, and their dendrimers. In an exemplary embodiment of the present disclosure, the polymeric polyol is an acrylic polyol.
In an embodiment of the present disclosure, the viscosity of the first component is in the range of 30 centipoise to 80 centipoise. In an exemplary embodiment of the present disclosure, the viscosity is 60 centipoise.
In an embodiment of the present disclosure, the second predetermined amount of the first fluid medium is in the range of 60 mass% to 70 mass% with respect to the total amount of the first fluid medium. In an exemplary embodiment of the present disclosure, the second predetermined amount of the first fluid medium is 64% with respect to the total amount of the first fluid medium.
In a fifth step, separately an organic polysilazane and a second fluid medium are blended at a speed in the range of 30 rpm to 80 rpm for a third predetermined time period to obtain a second component. In an exemplary embodiment of the present disclosure, the speed is 50 rpm.
In an embodiment of the present disclosure, the organic polysilazane is at least one selected from the group consisting of Durazene 1500 slow cure (mixture of polymethyl(hydro)/polymethylsilazane and 3-aminopropyltriethoxysilane), Durazene 1500 Rapid cure, Durazene 1800, Durazene 2250, Durazene 2850, dimethyl disilazane, trimethyl disilazane, tetramethyl disilazane, pentamethyl disilazane, hexamethyl disilazane, octamethyl trisilazane, hexamethylcyclo-trisilazane, tetraethyltetramethylcyclo tetrasilazane, tetraphenyldimethyl disilazane, dipropyltetramethyl disilazane, dibutyltetramethyl disilazane, dihexyltetramethyl disilazane, dioctyltetramethyl disilazane, diphenyl tetramethyl disilazane, octamethylcyclo tetrasilazane, cyclosilazane, and fluorine-containing organic silazane compound. In an exemplary embodiment of the present disclosure, the organic polysilazane is Durazene 1500 slow cure.
In an embodiment of the present disclosure, the second fluid medium is at least one selected from the group consisting of ortho-xylene, methyl amyl ketone, ethyl acetate, butyl acetate, and methoxypropyl acetate. In an exemplary embodiment of the present disclosure, the second fluid medium is a mixture of ortho-xylene, and methyl amyl ketone.
In an embodiment of the present disclosure, the third predetermined time period is in the range of 10 min to 60 min. In an exemplary embodiment of the present disclosure, the third predetermined time period is 15 min.
The so obtained first component and the second component are mixed to obtain the coating composition.
The coating composition of the present disclosure can be applied by conventional techniques such as ragging, brushing, wiping, rolling, and spraying.
In an embodiment of the present disclosure, the coating composition of the present disclosure forms a thin film on the substrate at a thickness in the range of 1 µm to 10 µm. In an exemplary embodiment of the present disclosure, the thickness of the film is 3 µm.
The present disclosure provides the coating composition, which on the application on the substrate has enhanced physical and mechanical properties such as pencil hardness, adhesion to the substrate, surface energy, solar factor, water contact angle, and visual light transmission. Further, the substrates applied with the coating composition have better dirt pickup resistance and durability.
The organosilane silane/alkyl silicate oligomer imparts mechanical properties such as scratch hardness, adhesion and modifies the surface properties thereby imparting self-cleaning property to the coating composition.
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: Synthesis of acrylic polyol
5 gm of styrene, 20.5 gm of methyl methacrylate, 12 gm of butyl acrylate, 12 gm of hydroxyethyl methacrylate, 0.5 gm of methacrylic acid, and 2.25 gm of tertiary butyl per benzoate were mixed to obtain a mixture. The mixture was slowly mixed with 47.5 gm of ortho-xylene for 4 hours at 140°C to 144°C, followed by digestion for 1 hour to obtain a reaction mixture. To the reaction mixture, 0.25 gm of tertiary butyl perbenzoate (chaser catalyst) was added and continued the reaction for 1 hour to obtain the reaction mass. The reaction mass was cooled to 75°C, followed by filtration using a 120-mesh nylon filter to obtain the acrylic polyol. The acid value of the acrylic polyol was 6 mg KOH/g and the hydroxyl value was 100 mg KOH/g. The acrylic polyol has a solids content of 50%.
Example 2: Process for the preparation of coating composition in accordance with the present disclosure
a) First component
2A was prepared as follows.
1600 gm of ortho xylene, 1200 gm of butyl acetate, and 300 gm of methyl amyl ketone were charged into a disperser followed by slowly adding ethyl cellulose under stirring at a speed of 50 rpm for 20 min to obtain a first mixture. To the first mixture, 250 gm of Tegodisperse 670, 250 gm of indium tin oxide nanopowder was added under stirring at a speed of 100 rpm for 30 min to obtain a second mixture (particle size 5 µm). The second mixture was subjected to an agitator bead mill to obtain a third mixture having a particle size of 150 nm. The third mixture was charged into a mixer followed by adding, 400 gm of acrylic polyol (from example 1), 545 gm of ortho xylene, 1000 gm of methyl amyl ketone, and 4205 gm of butyl acetate and blending for 30 min to obtain a product mixture. The product mixture was strained through an 80 mesh filter to obtain the first component. The viscosity of the first component was 50 centipoise, by using Brookfield viscometer.

2B was prepared as follows.
1600 gm of ortho xylene, 1200 gm of butyl acetate, and 300 gm of methyl amyl ketone were charged into a disperser followed by slowly adding ethyl cellulose under stirring at a speed of 50 rpm for 20 min to obtain the first mixture. To the first mixture, 250 gm of Tegodisperse 670, 50 gm of nanosilica (BET surface area 200 m2/g), 250 gm of indium tin oxide nanopowder was added under stirring at a speed of 100 rpm for 30 min to obtain a second mixture (particle size 5 µm). The second mixture was subjected to an agitator bead mill to obtain a third mixture having a particle size of 150 nm. The third mixture was charged into a mixer followed by adding 5 gm of BYK 085, 150 gm of Tegoflow 300, 400 gm of acrylic polyol (from example 1), 545 gm of ortho xylene, 1000 gm of methyl amyl ketone, and 4000 gm of butyl acetate and blending for 30 min to obtain a product mixture. The product mixture was strained through an 80 mesh filter to obtain the first component. The viscosity of the first component was 60 centipoise, by using Brookfield viscometer.
Table 1
Sr. No. Raw Material 2A (gm) 2B (gm)
1 Ortho xylene 2145 2145
2 Methyl amyl ketone 1300 1300
3 Butyl acetate 5405 5200
4 Ethyl cellulose (rheological agent) 250 250
5 Tego disperse 670 (copolymer with pigment affinic groups) 250 250
6 Nanosilica having BET surface area 200 m2/g 0 50
7 Indium tin oxide nanopowder (100 nm) 250 250
8 Polymethylalkylsiloxane (BYK-085) defoamer 0 5
9 Silicone-free polyacrylate (tego flow 300) 0 150
10 Acrylic polyol (obtained in example 1) 400 400
Total 10000 10000

b) Second component
2C was prepared as follows.
Separately, 1275 gm of organic polysilazane (Durazene 1500 slow cure from Merck) was charged into a high speed mixer, 4.36 kg of ortho-xylene and 4.36 kg of methyl amyl ketone was blended at a speed of 50 rpm in a nitrogen atmosphere for a period of 15 minutes to obtain a second component. The second component was prepared by using the ingredients having the amounts as specified in Table-2.
Table-2
Sr. No. Raw Material 2C (gm)
1 Ortho xylene 4363
2 Methyl amyl ketone 4362
3 Organic Polysilazane (DURAZENE 1500 slow cure from Merck) 1275

The so obtained first component (1000 gm) was mixed with the second component (1000 gm) by using a mechanical mixer for 5 min to 10 min to obtain the coating composition.
Examples 3-4: Process for the preparation of coating composition in accordance with the present disclosure
The first component of the coating composition was prepared similar to the process disclosed in Example 2a by varying the ingredients, the composition details are provided below in Table 3.

Table 3
Sr. No. Raw Material Example 3 (gm) Example 4 (gm)
1 Ortho xylene 2145 2145
2 Methyl amyl ketone 1300 1300
3 Butyl acetate 5180 5100
4 Ethyl cellulose (rheological agent) 250 250
5 Tego disperse 670 (high molecular weight polymer) 250 250
6 Nanosilica having BET surface area 200 m2/g 50 50
7 Indium tin oxide nanopowder (100 nm) 250 250
8 Polymethylalkylsiloxane (BYK-085) defoamer 5 5
9 Silicone-free polyacrylate (tego flow 300) 150 150
10 Acrylic polyol (obtained in example 1) 400 400
11 Dynasylan F 8261* 20 0
12 MKC Silicates MS56** 0 100
Total 10000 10000
* Dynasylan F 8261 was added during the preparation of third mixture of the first component
** MKC Silicates MS56 was added during the preparation of third mixture of the first component
Study of performance of the coating composition of the present disclosure on a glass substrate
Glass sample specimens of 5mm thickness with a dimension of 1 feet x 1 feet were taken and the coating composition of the present disclosure was applied by air-assisted spray coating (examples 2B, 3, and 4) and ragging using microfiber cloth (example 2A), and allowed to dry for 60 min to obtain a visually clear film on the glass substrate. The dry film thickness of the coating composition on the glass substrate was 3 microns.
The coating compositions obtained in experiments 2 to 4 were applied to the glass substrates by mixing in specific proportions, the details are provided below in Table 4.
Table 4: Coating on glass substrates
S. No Name % of first component % of second component
1 Substrate 1 50 of Example 2a (2A) 50 of Example 2b (2C)
2 Substrate 2 50 of Example 2a (2B) 50 of Example 2b (2C)
3 Substrate 3 50 of Example 3 50 of Example 2b (2C)
4 Substrate 4 50 of Example 4 50 of Example 2b (2C)

The coated glass substrates were evaluated for various film properties i.e. transparency (UV-Vis-NIR spectroscopy), solar factor using (UV-Vis-NIR spectroscopy), water contact angle, surface energy (goniometer), and pencil hardness (measured using Mitsubishi pencils from H to 4H with pencil hardness tester). The details are provided below in Table 5.
Table 5: Film properties
Sample Pencil hardness Adhesion to glass Water Contact Angle Surface Energy (mN/m) Solar Factor (%) Visual Light Transmission
Substrate 1 3H-4H 5B 90.5? 33.7 0.65 80%
Substrate 2 3H-4H 5B 93.50? 31.31 0.65 80%
Substrate 3 3H-4H 5B 103.41? 16.5 0.65 80%
Substrate 4 3H-4H 5B 43.65? 55.07 0.65 80%
Uncoated glass Not Applicable Not Applicable 30? 65 0.9 88%

Pencil hardness
The pencil hardness of the coated substrates 1, 2, 3, and 4 were determined according to ASTM D3363-20. The substrates were evaluated by using different pencils of varying hardness from H to 4H on the coating at 45-degree angle. It is evident from the above data that the four coated substrates 1, 2, 3, and 4 have a pencil hardness of 3H to 4H.
Adhesion to glass
The adhesion to the glass of the coated substrates 1, 2, 3, and 4 was determined by using cross-cut adhesion tape test according to ASTM D3359 – 17. It is evident from the above data that the three coated substrates 1, 2, 3, and 4 show excellent adhesion on glass (5B adhesion).
Water contact angle
It was observed from the results, that the water contact angle changes on the addition of the organosilane or alkyl silicate oligomer. These additives can migrate to the surface thereby influencing the surface properties and hence the water contact angles changes accordingly.
Solar factor
The solar factor of the coated substrates 1, 2, 3, and 4 exhibit solar factor was 0.65 (UV-Vis-NIR spectroscopy), whereas for the uncoated glass the solar factor was 0.9. The solar factor value of 1 indicates that 100% of heat was transmitted through the glass. Hence, the results indicate that the substrates coated with the coating composition of the present disclosure transmit less heat as compared to the uncoated glass.

Dirt pickup resistance test
The coated substrates 1, 2, 3, 4, and uncoated glass were evaluated for dirt pickup resistance by evaluating the change in transparency. The samples were exposed in the exterior (summer season, no rainfall, temperature 25°C to 35°C) at 90-degree angle for a period of 30 days. After 30 days, the substrates were subjected to forced airflow from a pedestal fan for 10 minutes; the transparency% after exposure and after forced airflow was measured by using the UV-Vis-NIR spectrophotometer. The results are provided below in Table 6.
Table 6: Dirt pickup resistance test
Sample Design % Change in
Transparency (After Exposure) % Change in
Transparency (After Forced Air flow)
Substrate 1 2A 12.37 12.13
Substrate 2 2B 11.14 10.74
Substrate 3 3A 14.41 8.62
Substrate 4 4A 7.75 5.35
Uncoated glass Blank glass 17.80 15.61
It is evident from the above data that coated substrates 1, 2, 3, and 4 exhibit better dirt pickup resistance as compared to the uncoated glass. The change in transparency because of dirt pickup for coated substrates 1, 2, 3, and 4 was less as compared to the uncoated glass before and after the forced airflow test.
Film Durability
The durability of the film on coated substrates 1, 2, 3, and 4 was evaluated by measuring the colour change value (Delta E). The colour change value (Delta E) was measured by using a spectrophotometer after exposing the coated substrates 1, 2, 3, and 4 for a period of 500 hours and 1000 hours in the accelerated weathering test (QUV A). The results are provided below in Table 7.
Table 7: Durability test
Sample DeltaE (Color change) DeltaE (Color change)
After 500 hours QUV A After 1000 hours QUV A
Substrate 1 0.72 0.89
Substrate 2 0.64 0.75
Substrate 3 0.596 0.95
Substrate 4 1.0 1.7

It is evident from the above results that the color change for all the substrates after exposure of 500 hours and 1000 hours was <2 (?E < 2). Further, no cracking, peeling, chalking, or yellowing on the surface of the coating was observed. From this data, it is evident that the coating on the four substrates has high durability.
TECHNICAL ADVANCEMENTS
The present disclosure described hereinabove has several technical advantages including, but not limited to, the realization of a coating composition that:
• is single coating and provides effective dirt pick up resistance (DPUR) as well as heat reduction property;
• can be cured at an ambient temperature;
• is fast drying < 5 mins of touch dry;
• can be applied on pre-installed glass;
• can be applied on the interior and/or the exterior of the glass;
• maintains glass transparency;
• enhanced film durability;
• has high visual light transmission;
• has good adhesion to glass; and
• offers various colors to installed glass.
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 comprising:
a. a first component comprising
i. a polymeric polyol in an amount in the range of 2 mass% to 5 mass% w.r.t the total mass of the first component;
ii. inorganic nanoparticles in an amount in the range of 1 mass% to 4 mass% w.r.t the total mass of the first component;
iii. a rheology modifier in an amount in the range of 1 mass% to 4 mass% w.r.t the total mass of the first component;
iv. a dispersing agent in an amount in the range of 1 mass% to 5 mass% w.r.t the total mass of the first component; and
v. a first fluid medium in an amount in the range of 80 mass% to 90 mass% w.r.t the total mass of the first component;
b. a second component comprising
i. an organic polysilazane in an amount in the range of 10 mass% to 20 mass% w.r.t the total mass of the second component; and
ii. a second fluid medium in an amount in the range of 80 mass% to 90 mass% w.r.t the total mass of the second component;
wherein said first component and said second component are mixed in a mass ratio in the range of 20:80 to 50:50 before application to obtain said coating composition.
2. The composition as claimed in claim 1, wherein said first component comprises at least one additive selected from a filler, a levelling agent, an anti-foaming agent, an adhesion promoter, and a surface modifying agent.
3. The composition as claimed in claim 1, wherein said polymeric polyol is at least one selected from the group consisting of polycarbonate polyol, polyester polyol, acrylic polyol, epoxy polyol, cellulosic polyol, polyether polyol, caprolactone based polyol, aldehyde resin-based polyol, ketonic resin-based polyol and their dendrimers.
4. The composition as claimed in claim 1, wherein said polymeric polyol is characterized by having a hydroxyl value in the range of 80 mg KOH/g to 120 mg KOH/g and an acid value in the range of 4 mg KOH/g to 8 mg KOH/g.
5. The composition as claimed in claim 2, wherein said filler is at least one selected from the group consisting of nanosilica, alumina, titania (titanium oxide), and zinc oxide; and said filler is present in an amount in the range of 0.2 mass% to 1 mass% w.r.t the total mass of the first component.
6. The composition as claimed in claim 2, wherein said filler has a BET surface area in the range of 90 m2/g to 400 m2/g.
7. The composition as claimed in claim 2, wherein said levelling agent is at least one selected from the group consisting of silicone-free polyacrylate (TEGO FLOW 300), polyether siloxane polymer (TEGO FLOW 425), silicone free solvent mixture of high boiling solvents (BYKETOL OK); and said levelling agent is present in an amount in the range of 1 mass% to 4 mass% w.r.t the total mass of the first component.
8. The composition as claimed in claim 1, wherein said inorganic nanoparticles are at least one selected from the group consisting of silicon dioxide, titanium dioxide, zinc oxide, aluminum oxide, antimony tin oxide, indium tin oxide, cesium tungsten oxide, aluminum zinc oxide, graphene nanoparticles, graphene oxide, reduced graphene oxide, carbon nanofibers, single walled carbon nanotubes, multi-walled carbon nanotubes, and nanoclays.
9. The composition as claimed in claim 1, wherein the particle size of said inorganic nanoparticles is in the range of 10 nm to 200 nm.
10. The composition as claimed in claim 1, wherein said rheology modifier is at least one selected from the group consisting of ethyl cellulose, polyamide, hydrogenated castor oil, organoclay and fumed silica.
11. The composition as claimed in claim 1, wherein said dispersing agent is at least one selected from the group consisting of a TEGO DISPERSE 670, DISPERBYK 111, DISPERBYK 103, DISPERBYK 2055, and DISPERBYK 163 (copolymer with pigment affinic groups).
12. The composition as claimed in claim 1, wherein said first fluid medium is at least one selected from the group consisting of ortho-xylene, methyl amyl ketone, butyl acetate, methyl isobutyl ketone, methoxy propyl acetate, and ethyl acetate.
13. The composition as claimed in claim 2, wherein said anti-foaming agent is at least one selected from the group consisting of polymethylalkylsiloxane (BYK-085), silicone-free solution of foam destroying substances (BYK A555, Efka PB 2020); and said anti-foaming agent is present in an amount in the range of 0.01 mass% to 0.1 mass% w.r.t the total mass of the first component.
14. The composition as claimed in claim 2, wherein said adhesion promoter is at least one selected from the group consisting of 3-aminopropyltriethoxysilane, 3-glycidoxypropyltriethoxysilane, methyltrimethoxysilane, DYNASYLAN F 8261 (bifunctional silane possessing hydrolyzable inorganic ethoxysilyl groups and a fluoroalkyl chain); and said adhesion promoter is present in an amount in the range of 0.01 mass% to 2 mass% w.r.t the total mass of the first component.
15. The composition as claimed in claim 2, wherein said surface modifying agent is alkyl silicate oligomer at least one selected from the group consisting of methyl silicate oligomer (MKC MS56), and ethyl silicate oligomer; and said surface modifying agent is present in an amount in the range of 0.5 mass% to 3 mass% w.r.t the total mass of the first component.
16. The composition as claimed in claim 1, wherein said organic polysilazane is at least one selected from the group consisting of DURAZENE 1500 SLOW CURE (mixture of polymethyl(hydro)/polymethylsilazane and 3-aminopropyltriethoxysilane), DURAZENE 1500 RAPID CURE, DURAZENE 1800, DURAZENE 2250, DURAZENE 2850, dimethyl disilazane, trimethyl disilazane, tetramethyl disilazane, pentamethyl disilazane, hexamethyl disilazane, octamethyl trisilazane, hexamethylcyclo-trisilazane, tetraethyltetramethylcyclo tetrasilazane, tetraphenyldimethyl disilazane, dipropyltetramethyl disilazane, dibutyltetramethyl disilazane, dihexyltetramethyl disilazane, dioctyltetramethyl disilazane, diphenyl tetramethyl disilazane, octamethylcyclo tetrasilazane, cyclosilazane, and fluorine-containing organic silazane compound.
17. The composition as claimed in claim 1, wherein said second fluid medium is at least one selected from the group consisting of ortho-xylene, methyl amyl ketone, ethyl acetate, butyl acetate, and methoxypropyl acetate.
18. The composition as claimed in claim 1, wherein said coating composition is coated on a substrate, said substrate is selected from the group consisting of glass, metal, plastic, and concrete.
19. The composition as claimed in claim 18, wherein said coated substrate is characterized by having
a. a visible light transmission in the range of 80% to 90%;
b. a water contact angle in the range of 40° to 110°;
c. a surface energy in the range of 15 mN/m to 60 mN/m; and
d. a solar factor in the range of 0.5 to 0.7;
20. A process for the preparation of the coating composition as claimed in claim 1, said process comprising the following steps:
a. blending a first predetermined amount of first fluid medium, a rheology modifier at a speed in the range of 30 rpm to 80 rpm for a first predetermined time period to obtain a first mixture;
b. adding a dispersing agent, and inorganic nanoparticles to said first mixture and blending at a speed in the range of 80 rpm to 120 rpm for a second predetermined time period to obtain a second mixture;
c. milling said second mixture to obtain a third mixture with a particle size in the range of 10 nm to 200 nm;
d. adding a second predetermined amount of said first fluid medium and a polymeric polyol to said third mixture and blending at a speed in the range of 30 rpm to 80 rpm for a time period in the range of 10 min to 60 min to obtain a first component;
e. separately blending an organic polysilazane and a second fluid medium at a speed in the range of 30 rpm to 80 rpm for a third predetermined time period to obtain a second component; and
f. mixing said first component and said second component before application to obtain said coating composition.
21. The process as claimed in claim 20, wherein said first predetermined time period is in the range of 10 min to 60 min.
22. The process as claimed in claim 20, wherein said second predetermined time period is in the range of 20 min to 40 min.
23. The process as claimed in claim 20, wherein said third predetermined time period is in the range of 10 min to 60 min.
24. The process as claimed in claim 20, wherein the viscosity of said first component and said second component is independently in the range of 30 centipoise to 80 centipoise.
25. The process as claimed in claim 20, wherein said first predetermined amount of said first fluid medium is in the range of 30 mass% to 40 mass% with respect to the total amount of the first fluid medium and said second predetermined amount of said first fluid medium is in the range of 60 mass% to 70 mass% with respect to the total amount of the first fluid medium.
26. The process as claimed in claim 20, wherein at least one additive is added in step b) to step d) to obtain said first component.
27. The process as claimed in claim 26, wherein said at least one additive is selected from a filler, a levelling agent, an anti-foaming agent, an adhesion promoter, and a surface modifying agent.

Dated this 23rd day of March, 2022

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

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