Claims:1. A polymeric binder composition, said polymeric binder composition comprising the following:
i) an acrylic polyol component having hydroxyl value in the range of 50 mg KOH/g to 200 mg KOH/g;
ii) a polyolefinic component having GPC average molecular weight in the range of 3,000 to 30,000, and an acid value in the range of 30 mg KOH/g to 100 mg KOH/g; and
iii) at least one fluid medium,
wherein said polymeric binder composition is characterized by having:
- hydroxyl value in the range of 30 mg KOH/g to 200 mg KOH/g;
- acid value in the range of 2 mg KOH/g to 15 mg KOH/g; and
- viscosity in the range 500 cps to 5000 cps at 60 % solid concentration,
wherein said polymeric binder composition is configured to provide a glossy and transparent coating having a gloss value in the range of 85 % to 100 % at 60 ° inclination, and a light transmittance value in the range of 90 % to 99.99 %.
2. The polymeric binder composition as claimed in claim 1, wherein said acrylic polyol component is obtained by reacting at least one hydroxy acrylate monomer with at least one acrylate monomer.
3. The polymeric binder composition as claimed in claim 2, wherein said at least one hydroxy acrylate monomer is selected from the group consisting of hydroxyethyl acrylate, hydroxyl-ethoxyethyl acrylate, hydroxyl-poly(ethoxy)ethyl acrylate, and hydroxymethyl acrylate.
4. The polymeric binder composition as claimed in claim 2, wherein said at least one acrylate monomer is selected from the group consisting of butyl acrylate, n-butyl acrylate, methyl acrylate, methyl methacrylate, acrylic acid, and methacrylic acid.
5. The polymeric binder composition as claimed in claim 1, wherein said at least one polyolefinic component is selected from the group consisting of linear polyethylene, branched polyethylene, ethylene copolymer, polypropylene, and propylene copolymer.
6. The polymeric binder composition as claimed in claim 1, wherein said at least one fluid medium is selected from aromatic hydrocarbons and aliphatic esters.
7. The polymeric binder composition as claimed in claim 1, wherein said polymeric binder composition further comprises at least one aceto-acetate component.
8. The polymeric binder composition as claimed in claim 1, wherein said polymeric binder composition further comprises at least one vinylated aromatic component selected from the group consisting of styrene, vinyltoluene, and methylstyrene.
9. A process for preparing a polymeric binder composition, said process comprising the following steps:
a. mixing at least one hydroxy acrylate monomer, at least one acrylate monomer, at least one free radical initiator, and optionally at least one first fluid medium to obtain a resultant mixture;
b. heating said resultant mixture at a temperature in the range of 90 °C to 150 °C to obtain an acrylic polyol component having hydroxyl value in the range of 50 mg KOH/g to 200 mg KOH/g and viscosity in the range 500 cps to 5000 cps at 60 % solid concentration; and
c. mixing said acrylic polyol component with a polyolefinic component having GPC average molecular weight in the range of 3,000 to 30,000, and an acid value in the range of 30 mg KOH/g to 100 mg KOH/g and heating at a temperature in the range of 120 °C to170 °C in the presence of a second fluid medium, to obtain said polymeric binder composition,
wherein said polymeric binder composition is characterized by having:
- hydroxyl value in the range of 30 mg KOH/g to 200 mg KOH/g;
- acid value in the range of 2 mg KOH/g to 15 mg KOH/g; and
- viscosity in the range 500 cps to 5000 cps at 60 % solid concentration,
wherein said polymeric binder composition is configured to provide a glossy and transparent coat having a gloss value in the range of 85 % to 100 % at 60 ° inclination, and a light transmittance value in the range of 90 % to 99.99 %.
10. The process for preparing said polymeric binder composition as claimed in claim 9, wherein said at least one hydroxy acrylate monomer, said at least one acrylate monomer, said at least one free radical initiator, said polyolefin component, and said at least one first fluid medium are mixed simultaneously and heated at a temperature in the range of 90 °C to 150 °C to obtain said polymeric binder composition.
11. The process as claimed in claim 9 or claim 10, wherein said at least one free radical initiator is selected from the group consisting of tert-butylperoxy 2-ethylhexyl carbonate, tert-butyl peroxybenzoate, lauroyl peroxide, di- tert-butyl peroxide 98 %, benzoyl peroxide, di-tertiary amyl peroxide, 1,1-bis(tert-amylperoxy)cyclohexane, dicumyl peroxide, tert-butyl hydroperoxide, tert-butyl peracetate, and azo-bis-isobutyronitrile
12. The process as claimed in claim 9 or claim 10, wherein at least one vinylated aromatic component selected from the group consisting of styrene, vinyltoluene, and methylstyrene is mixed with said hydroxyl acrylate monomer and said at least one acrylate monomer.
13. The process as claimed in claim 9 or claim 10, wherein at least one aceto-acetate component is mixed with said hydroxyl acrylate monomer and said at least one acrylate monomer.
14. An anti-graffiti coating composition, said anti-graffiti coating composition comprising the following:
a. polymeric binder composition comprising:
i. an acrylic polyol component having hydroxyl value in the range of 50 mg KOH/g to 200 mg KOH/g;
ii. a polyolefinic component having GPC average molecular weight in the range of 3,000 to 30,000, and an acid value in the range of 30 mg KOH/g to 100 mg KOH/g;
wherein said polymeric binder composition is characterized by having:
- hydroxyl value in the range of 30 mg KOH/g to 180 mg KOH/g;
- acid value in the range of 2 mg KOH/g to 15 mg KOH/g; and
- viscosity in the range 500 cps to 5000 cps at 60 % solid concentration;
b. pre-determined amount of at least one curing agent; and
c. pre-determined amount of at least one fluid medium,
wherein said anti-graffiti coating composition is configured to provide a glossy and transparent coating having a gloss value in the range of 90 % to 95 % at 60 ° inclination, and a water beading contact angle >90°.
15. The anti-graffiti coating composition as claimed in claim 14, wherein the proportion of said polymeric binder composition is in the range of 40 wt% to 80 wt%, the proportion of said curing agent is in the range of 10 wt% to 40 wt%, and the proportion of said fluid medium is in the range of 5 wt% to 40 wt%.
16. The anti-graffiti coating composition as claimed in claim 14, wherein said polymeric binder composition further comprises at least one aceto-acetate component.
17. The anti-graffiti coating composition as claimed in claim 14, wherein said at least one curing agent is selected from the group consisting of poly isocyanate, melamine-formaldehyde, urea formaldehyde, unimolecular amines, unimolecular amides, unimolecular amido-amines, unimolecular imido-amines, polyamines, polyamides, polyamido-amines, and polyimido-amines.
18. The anti-graffiti coating composition as claimed in claim 14, wherein said anti-graffiti coating composition further comprises at least one vinylated aromatic component selected from the group consisting of styrene, vinyltoluene, and methylstyrene.
19. The anti-graffiti coating composition as claimed in claim 14, wherein said anti-graffiti composition further comprises at least one catalyst selected from the group consisting of dibutyltin dilaurate, dibutyltin diacetate, titanium tetrabutoxide, 1,4-diazabicyclo[2,2,2]-octane, metal dionate complex, Co, Zn, Bi salts of isooctate, Co, Zn, Bi salts of 2-ethylhexoate, and Zn and Ti acetoacetate complexes, in the range of 0.05 wt% to 0.3 wt%.
20. The anti-graffiti coating composition as claimed in claim 14, wherein said anti-graffiti coating composition is diluted with a diluent before application/use.
21. The anti-graffiti coating composition as claimed in claim 20, wherein said diluent is selected from the group consisting of o-xylene, mix-xylene, butyl acetate, methoxy propyl acetate, methyl isobutyl ketone, C9 aromatic hydrocarbon solvents, and combinations thereof and wherein the proportion of said diluent is in the range of 10 wt% to 30 wt% of said anti-graffiti coating composition.
22. The anti-graffiti coating composition as claimed in claim 14, wherein said anti-graffiti coating composition further comprises a pigment and is configured to provide a pigmented coating.
23. A process for preparing an anti-graffiti coating composition, said process comprising the following steps:
a. mixing at least one hydroxy acrylate monomer, at least one acrylate monomer, at least one free radical initiator, and optionally at least one first fluid medium to obtain a resultant mixture;
b. heating said resultant mixture at a temperature in the range of 90 °C to 150 °C to obtain an acrylic polyol component having hydroxyl value in the range of 50 mg KOH/g to 200 mg KOH/g viscosity in the range 500 cps to 5000 cps at 60 % solid concentration;
c. mixing said acrylic polyol component with a polyolefinic component having GPC average molecular weight in the range of 3,000 to 30,000 and an acid value in the range of 30 mg KOH/g to 100 mg KOH/g and heating at a temperature in the range of 120 °C to170 °C in the presence of a second fluid medium, to obtain a polymeric binder composition,
wherein said polymeric binder composition is characterized by having:
- hydroxyl value in the range of 30 mg KOH/g to 180 mg KOH/g;
- acid value in the range of 2 mg KOH/g to 15 mg KOH/g; and
- viscosity in the range 500 cps to 5000 cps at 60 % solid concentration; and
d. mixing a pre-determined amount of at least one curing agent, and a pre-determined amount of at least one third fluid medium to said polymeric binder composition to obtain said anti-graffiti coating composition,
wherein said anti-graffiti coating composition is configured to provide a glossy and transparent coating having a gloss value in the range of 90 % to 95 % at 60 ° inclination, and a water beading contact angle >90°.
24. The process for preparing said anti-graffiti coating composition as claimed in claim 24, wherein said at least one hydroxy acrylate monomer, said at least one acrylate monomer, said at least one free radical initiator, said polyolefin component and said at least one first fluid medium are mixed simultaneously and heated at a temperature in the range of 90 °C to 150 °C to obtain said polymeric binder composition.
25. The process as claimed in claim 23 or claim 24, wherein at least one vinylated aromatic hydrocarbon component from the group consisting of styrene, vinyltoluene, and methylstyrene is mixed with said hydroxyl acrylate monomer and said acrylate monomer.
26. The process as claimed in claim 23 or claim 24, wherein said at least one first fluid medium, said at least one second fluid medium, and said at least one third fluid medium are independently selected from aromatic hydrocarbons and aliphatic esters.
27. The process as claimed in claim 23 or claim 24, wherein said at least one free radical initiator is selected from the group consisting of tert-butylperoxy 2-ethylhexyl carbonate, tert-butyl peroxybenzoate, lauroyl peroxide, di- tert-butyl peroxide 98 %, benzoyl peroxide, di-tertiary amyl peroxide, 1,1-bis(tert-amylperoxy)cyclohexane, dicumyl peroxide, tert-butyl hydroperoxide, tert-butyl peracetate, and azo-bis-isobutyronitrile.
28. The process as claimed in claim 23 or claim 24, wherein at least one aceto-acetate component is mixed with said hydroxyl acrylate monomer and said acrylate monomer.
29. The process as claimed in claim 23 or claim 24, wherein said wherein said at least one curing agent is selected from the group consisting of poly isocyanate, melamine-formaldehyde, and urea formaldehyde, unimolecular amines, unimolecular amides, unimolecular amido-amines, unimolecular imido-amines, polyamines, polyamides, polyamido-amines, and polyimido-amines.
30. The process as claimed in claim 23 or claim 24 further comprises the adding at least one catalyst selected from the group consisting of dibutyltin dilaurate, dibutyltin diacetate, titanium tetrabutoxide, 1,4-diazabicyclo[2,2,2]-octane, metal dionate complex, Co, Zn, Bi salts of isooctate, Co, Zn, Bi salts of 2-ethylhexoate, and Zn and Ti acetoacetate complexes, to the process step (d).
31. The process as claimed in claim 23 or claim 24 further comprises a step of adding a pigment to said polymeric binder composition, such that the anti-graffiti coating composition provides a pigmented coating.
, Description:FIELD
The present disclosure relates to polymeric binder compositions and anti-graffiti coating compositions prepared therefrom.
DEFINITIONS
As used in the present disclosure, the following terms are generally intended to have the meaning as set forth below, except to the extent that the context in which they are used indicates otherwise.
GPC average molecular weight: Gel permeation chromatography (GPC) is a type of size exclusion chromatography (SEC) that separates analytes on the basis of size and can be used to characterize the complete molecular weight distribution of a polymer.
Hydroxyl value: The term “hydroxyl value” refers to the number of milligrams of potassium hydroxide required to neutralize the acetic acid taken up on acetylation of one gram of a chemical substance that contains free hydroxyl groups.
Acid value: The term “acid value” also known as “neutralization number" or "acid number" or "acidity”, refers to the mass of potassium hydroxide (KOH) in milligrams that is required to neutralize one gram of a chemical substance.
Coating: The term “coating” refers to a layer or a film formed by applying a binder composition or an anti-graffiti coating composition on a substrate.
Gloss value: The term “gloss value” refers to the perception by an observer of the shiny appearance of a surface. This perception changes whenever there is a change in the relative position or spectral distribution of the source, the sample, or the observer. Gloss is determined by projecting a beam of light at a fixed intensity and angle onto a surface and measuring the amount of reflected light at an equal but opposite angle.

BACKGROUND
Graffiti are writing or drawings that have been scribbled, scratched, or painted illicitly on a wall or other surface, often within public view. Graffiti can be defined as the marking of other people's property without their consent. Graffiti range from simple written words to elaborate wall paintings.
However, graffiti is regarded by many to be unsightly. Graffiti vandalism is one of biggest problem across the globe as structures and appurtenances affected by graffiti vandalism include bridges, sound walls, retaining walls, barrier rails, traffic signs, bus, monuments, school, government buildings, and the like. The cost associated with cleaning and/or removing graffiti from a property is considerable.
Therefore, attempts have been made across the globe to develop coatings to prevent vandals from defacing public and private property. Generally silicone, fluoro, and fluorosilicone based binders and additives are widely used for anti-graffiti coatings. Modified low molecular weight polyolefin has been used as one of the components in the synthesis of the anti-graffiti coatings having mar-resistant and anti-graffiti properties. Silicone, fluoro and fluorosilicone based binders are used as permanent anti-graffiti coatings with potential of removal of graffiti’s for multiple times and lasting anti-graffiti performance. However, anti-graffiti coatings prepared from silicone and fluoro compounds based additives have lower anti-graffiti performance after short period of exposure. Further, these binders and additives are expensive.
Therefore, there is felt a need to provide anti-graffiti binders and additives that mitigate the drawbacks mentioned hereinabove.
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 polymeric binder composition.
Still another object of the present disclosure is to provide a process for the preparation of a polymeric binder composition.
Yet another object of the present disclosure is to provide an anti-graffiti coating composition.
Still another object of the present disclosure is to provide a cost effective anti-graffiti coating composition.
Yet another object of the present disclosure is to provide a process for the preparation of an anti-graffiti 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 provides a polymeric binder composition. The polymeric binder composition comprises i) an acrylic polyol component having hydroxyl value in the range of 50 mg KOH/g to 200 mg KOH/g, ii) a polyolefinic component having GPC average molecular weight in the range of 3,000 to 30,000, and an acid value in the range of 30 mg KOH/g to 100 mg KOH/g; and iii) at least one fluid medium. The polymeric binder composition is characterized by having hydroxyl value in the range of 30 mg KOH/g to 180 mg KOH/g, acid value in the range of 2 mg KOH/g to 15 mg KOH/g, and viscosity in the range 500 cps to 5000 cps at 60 % solid concentration. The polymeric binder composition is configured to provide a glossy and transparent coat having a gloss value in the range of 85 % to 100 % at 60 ° inclination, and a light transmittance value in the range of 90 % to 99.99 %. The acrylic polyol component is obtained by reacting at least one hydroxy acrylate monomer with at least one acrylate monomer. The polymeric binder composition can optionally comprise at least one aceto-acetate component, and/or a vinylated aromatic component.
The process for preparing the polymeric binder composition comprises mixing at least one hydroxy acrylate monomer, at least one acrylate monomer, at least one free radical initiator, and optionally at least one first fluid medium to obtain a resultant mixture. The resultant mixture is heated at a temperature in the range of 90 °C to 150 °C to obtain an acrylic polyol component, which is mixed with a polyolefinic component and heated at a temperature in the range of 120 °C to 170 °C in the presence of a second fluid medium, to obtain the polymeric binder composition.
The present disclosure further provides an anti-graffiti coating composition. The anti-graffiti coating composition is configured to provide a glossy and transparent coating having a gloss value in the range of 90 % to 95 % at 60 ° inclination, and a water beading contact angle >90°.The anti-graffiti coating composition comprises a polymeric binder composition, pre-determined amount of at least one curing agent, and at least one fluid medium. The polymeric binder composition comprises an acrylic polyol component, and a polyolefinic component having GPC average molecular weight in the range of 3,000 to 30,000 and an acid value in the range of 30 mg KOH/g to 100 mg KOH/g. Typically, the polymeric binder composition is characterized by hydroxyl value in the range of 30 mg KOH/g to 180 mg KOH/g, acid value in the range of 2 mg KOH/g to 15 mg KOH/g, and viscosity in the range 500 cps to 5000 cps at 60 % solid concentration,. Typically, the anti-graffiti coating composition is diluted with a diluent before application/use. In one embodiment, the anti-graffiti coating composition comprises a pigment and is configured to provide a pigmented coating.
The present disclosure further provides a process for preparing an anti-graffiti coating composition. The process comprises mixing at least one hydroxy acrylate monomer, at least one acrylate monomer, at least one free radical initiator, and optionally at least one first fluid medium to obtain a resultant mixture. The resultant mixture is heated at a temperature in the range of 90 °C to 150 °C to obtain an acrylic polyol component, which is blended with a polyolefinic component and heated at a temperature in the range of 120 °C to 170 °C in the presence of a second fluid medium, to obtain a polymeric binder composition. At least one curing agent and at least one third fluid medium are mixed with the polymeric binder composition to obtain the anti-graffiti coating composition.
In one embodiment, at least one hydroxy acrylate monomer, at least one acrylate monomer, at least one free radical initiator, the polyolefinic component, and at least one first fluid medium are mixed simultaneously and heated at a temperature in the range of 90 °C to 150 °C to obtain the polymeric binder composition.
DETAILED DESCRIPTION
Graffiti vandalism is a major problem across the globe. The cost associated with cleaning and/or removing graffiti from a property is considerable. Attempts have been made to develop coatings to prevent vandals from defacing public and private property. Generally, silicone, fluoro, and fluorosilicone based binders and additives are used for anti-graffiti coatings. Modified low molecular weight polyolefin has been used as one of the components in the synthesis of the anti-graffiti coatings having mar-resistant and anti-graffiti properties. However, anti-graffiti coatings prepared from silicone and fluoro compounds based additives have lower anti-graffiti performance after short period of exposure. Further, these binders and additives are expensive.
The present disclosure envisages a binder that is affordably priced and when used in anti-graffiti coating composition provides hardness, slip, mar, and anti-graffiti properties.
In one aspect of the present disclosure, there is provided a polymeric binder composition. The polymeric binder composition comprises i) an acrylic polyol component having hydroxyl value in the range of 50 mg KOH/g to 200 mg KOH/g, ii) a polyolefinic component having GPC average molecular weight in the range of 3,000 to 30,000, and an acid value in the range of 30 mg KOH/g to 100 mg KOH/g, and iii) at least one fluid medium.
Typically, the polymeric binder composition is characterized by having:
- hydroxyl value in the range of 30 mg KOH/g to 180 mg KOH/g,
- acid value in the range of 2 mg KOH/g to 15 mg KOH/g, and
- viscosity in the range 500 cps to 5000 cps at 60 % solid concentration.
The polymeric binder composition is configured to provide a glossy and transparent coat having a gloss value in the range of 85 % to 100 % at 60 ° inclination, and a light transmittance value in the range of 90 % to 99.99 %. The polymeric binder composition can be applied directly (casting) to a substrate, such as metal, glass, wood, stone, and masonry surface using different application tools, such as brushing, rolling and spraying, to obtain the glossy and transparent coat. Alternatively, the polymeric binder composition can be cured using a curing agent and then applied to a substrate to obtain the glossy and transparent coat. Typically, the curing agent can be selected from the group consisting of poly isocyanate, melamine-formaldehyde, urea formaldehyde, unimolecular amines, unimolecular amides, unimolecular amido-amines, unimolecular imido-amines, polyamines, polyamides, polyamido-amines, and polyimido-amines.
Typically, the gloss value can be measured using a gloss meter and the light transmittance value can be measured using a UV spectrophotometer.
Typically, the acrylic polyol component is obtained by reacting at least one hydroxy acrylate monomer with at least one acrylate monomer. The at least one hydroxy acrylate monomer can be selected from the group consisting of hydroxyethyl acrylate, hydroxyl-ethoxyethyl acrylate, hydroxyl-poly(ethoxy)ethyl acrylate, and hydroxymethyl acrylate. The at least one acrylate monomer is selected from the group consisting of butyl acrylate, n-butyl acrylate, methyl acrylate, methyl methacrylate, acrylic acid, and methacrylic acid.
The at least one polyolefinic component can be selected from the group consisting of linear polyethylene, branched polyethylene, ethylene copolymer, polypropylene, and propylene copolymer. The acid value of the polyolefinic component is higher as compared to that of the polymeric binder composition and is a critical parameter in for selecting the appropriate polyolefinic component for the polymeric binder composition.
In one embodiment, the polymeric binder composition comprises at least one aceto-acetate component, in an amount in the range of 10 wt% to 30 wt%.
The fluid medium can be selected from aromatic hydrocarbons and aliphatic esters.
In an embodiment, the polymeric binder composition comprises at least one vinylated aromatic component selected from the group consisting of styrene, vinyltoluene, and methylstyrene.
In second aspect of the present disclosure, there is provided a process for preparing a polymeric binder composition. The process comprises mixing at least one hydroxy acrylate monomer, at least one acrylate monomer, at least one free radical initiator, and optionally at least one first fluid medium to obtain a resultant mixture.
The at least one hydroxy acrylate monomer can be selected from the group consisting of hydroxyethyl acrylate, hydroxyl-ethoxyethyl acrylate, hydroxyl-poly(ethoxy)ethyl acrylate, and hydroxymethyl acrylate.
The at least one acrylate monomer can be selected from the group consisting of butyl acrylate, n-butyl acrylate, methyl acrylate, methyl methacrylate, acrylic acid, and methacrylic acid.
The at least one polyolefinic component can be selected from the group consisting of linear polyethylene, branched polyethylene, ethylene copolymer, polypropylene, and propylene copolymer. Typically, the GPC average molecular weight of the polyolefinic component can be in the range of 3,000 to 30,000, and an acid value in the range of 30 mg KOH/g to 100 mg KOH/g.
The at least one free radical initiator can be selected from the group consisting of tert-butylperoxy 2-ethylhexyl carbonate, tert-butyl peroxybenzoate, lauroyl peroxide, di- tert-butyl peroxide 98 %, benzoyl peroxide, di-tertiary amyl peroxide, 1,1-bis(tert-amylperoxy)cyclohexane, dicumyl peroxide, tert-butyl hydroperoxide, tert-butyl peracetate, and azo-bis-isobutyronitrile.
The at least one first fluid medium can be selected from aromatic hydrocarbons and aliphatic esters.
The resultant mixture so obtained is heated at a temperature in the range of 90 °C to 150 °C to obtain an acrylic polyol component having hydroxyl value in the range of 50 mg KOH/g to 200 mg KOH/g and viscosity in the range 500 cps to 5000 cps at 60 % solid concentration,
The acrylic polyol component is mixed with a polyolefinic component and heated at a temperature in the range of 120 °C to170 °C in the presence of a second fluid medium, to obtain a polymeric binder composition.
Typically, the polyolefinic component has a GPC average molecular weight in the range of 3,000 to 30,000, and an acid value in the range of 30 mg KOH/g to 100 mg KOH/g. The polyolefinic component can be selected from the group consisting of linear polyethylene, branched polyethylene, ethylene copolymer, polypropylene, and propylene copolymer.
The at least one second fluid medium can be selected from aromatic hydrocarbons and aliphatic esters.
Alternatively, in one embodiment of the present disclosure, the polymeric component can be prepared by mixing at least one hydroxy acrylate monomer, at least one acrylate monomer, at least one free radical initiator, a polyolefin having GPC average molecular weight in the range of 3,000 to 30,000, and an acid value in the range of 30 mg KOH/g to 100 mg KOH/g, and at least one first fluid medium simultaneously and heating at a temperature in the range of 90 °C to 150 °C to obtain the polymeric binder composition.
In one embodiment, at least one aceto-acetate component, in an amount in the range of 10 wt% to 30 wt%, is mixed with the hydroxyl acrylate monomer. Typically, the aceto-acetate component is mixed with the at least one hydroxyl acrylate monomer and the at least one acrylate monomer.
In another embodiment, at least one vinylated aromatic component selected from the group consisting of styrene, vinyltoluene, and methylstyrene is mixed with the at least one hydroxyl acrylate monomer and at least one acrylate monomer.
In third aspect of the present disclosure, there is provided an anti-graffiti coating composition. The anti-graffiti coating composition comprises the following:
i) a polymeric binder composition comprising an acrylate polyol, and a polyolefinic component;
ii) pre-determined amount of at least one curing agent; and
iii) at least one fluid medium.
The anti-graffiti coating composition is configured to provide a glossy and transparent coating having a gloss value in the range of 90 % to 95 % at 60 ° inclination, and a water beading contact angle >90°.
Further, the polymeric binder composition is characterized by having hydroxyl value in the range of 30 mg KOH/g to 180 mg KOH/g, acid value in the range of 2 mg KOH/g to 15 mg KOH/g, and viscosity in the range 500 cps to 5000 cps at 60 % solid concentration.
Typically, the proportion of the polymeric binder composition is in the range of 40 wt% to 80 wt%. In an embodiment, the proportion of the polymeric binder composition is in the range of 50 wt% to 70 wt%.
The acrylic polyol component is obtained by reacting at least one hydroxy acrylate monomer with at least one acrylate monomer. The hydroxy monomers can be selected from the group consisting of hydroxyethyl acrylate, hydroxyl-ethoxyethyl acrylate, hydroxyl-poly(ethoxy)ethyl acrylate, and hydroxymethyl acrylate. The acrylate monomers can be selected from the group consisting of butyl acrylate, n-butyl acrylate, methyl acrylate, methyl methacrylate, acrylic acid, and methacrylic acid.
The at least one polyolefinic component can be selected from the group consisting of linear polyethylene, branched polyethylene, ethylene copolymer, polypropylene, and propylene copolymer. Typically, the GPC average molecular weight of the polyolefinic component can be in the range of 3,000 to 30,000 and acid value in the range of 30 mg KOH/g to 100 mg KOH/g.
In still another embodiment, the polymeric binder composition further comprises at least one vinylated aromatic component selected from the group consisting of styrene, vinyltoluene, and methylstyrene.
Typically, the weight proportion of the acrylic polyol component to the polyolefinic component is in the range of 99:1 to 90:10.
The at least one fluid medium can be selected from aromatic hydrocarbons and aliphatic esters. Typically, the proportion of the fluid medium is in the range of 5 wt% to 40 wt%. In one embodiment, the proportion of the fluid medium is in the range of 10 wt% to 30 wt%.
In one embodiment, the polymeric binder composition further comprises at least one aceto-acetate component.
The at least one curing agent can be selected from the group consisting of poly isocyanate, melamine-formaldehyde, urea formaldehyde, unimolecular amines, unimolecular amides, unimolecular amido-amines, unimolecular imido-amines, polyamines, polyamides, polyamido-amines, and polyimido-amines. Typically, the proportion of the curing agent is in the range of 10 wt% to 40 wt%. In one embodiment, the proportion of the curing agent is in the range of 15 wt% to 30 wt%.
In one embodiment, the anti-graffiti coating composition further comprises at least one catalyst. The at least one catalyst can be selected from the group consisting of dibutyltin dilaurate, dibutyltin diacetate, titanium tetrabutoxide, 1,4-diazabicyclo[2,2,2]-octane, metal dionate complex, Co, Zn, Bi salts of isooctate, Co, Zn, Bi salts of 2-ethylhexoate, and Zn and Ti acetoacetate complexes. Typically, the metal dionate complex can be formed by the interaction of Zn, Zr, Bi, Co, Mn, Al, and Ni, with 2,4-pentanedione. Typically, the proportion of the catalyst is in the range of 0.05 wt% to 0.3 wt%. In one embodiment, the proportion of the catalyst is in the range of 0.05 wt% to 0.2 wt%.
Typically, the anti-graffiti coating composition is diluted with a diluent before application/use. The diluent is selected from the group consisting of o-xylene, mix-xylene, butyl acetate, methoxy propyl acetate, methyl isobutyl ketone, C9 aromatic hydrocarbon solvents, and combinations thereof. The proportion of the diluent is in the range of 10 wt% to 30 wt% of the anti-graffiti coating composition.
The polymeric binder composition of the anti-graffiti coating composition is clear and translucence in nature. When this polymeric binder composition (polyolefin modified acrylic polyol) is cross linked with a curing agent, such as poly isocyanate, the resultant cured film is also transparent and glossy in nature (Gloss value >90 % at 60° inclination).
The anti-graffiti coating composition of the present disclosure can be applied on various substrates, such as metal, glass, wood, stone, and masonry surface using different application tools, such as brushing, rolling and spraying.
In one embodiment, a pigment is added to the anti-graffiti coating composition further comprises a pigment, and the anti-graffiti coating composition is configured to provide a pigmented coating. In one embodiment, the pigment is titanium dioxide (TiO2).
In fourth aspect of the present disclosure, there is provided a process for preparing an anti-graffiti coating composition. The process comprises mixing at least one hydroxy acrylate monomer, at least one acrylate monomer, at least one free radical initiator, and optionally at least one first fluid medium, and heating to obtain an acrylic polyol component. The acrylic polyol component is mixed with a low molecular weight polyolefinic component having high acid value in the presence of a second fluid medium to obtain a polymeric binder composition, which is then mixed with a curing agent, and a third fluid medium to obtain the anti-graffiti coating composition. The process is hereinafter described in detail.
Initially, at least one hydroxy acrylate monomer, at least one acrylate monomer, at least one free radical initiator, and optionally at least one first fluid medium are mixed to obtain a resultant mixture.
The at least one hydroxy acrylate monomer can be selected from the group consisting of hydroxyethyl acrylate, hydroxyl-ethoxyethyl acrylate, hydroxyl-poly(ethoxy)ethyl acrylate, and hydroxymethyl acrylate.
The at least one acrylate monomer can be selected from the group consisting of butyl acrylate, n-butyl acrylate, methyl acrylate, methyl methacrylate, acrylic acid, and methacrylic acid.
The at least one free radical initiator can be selected from the group consisting of tert-butylperoxy 2-ethylhexyl carbonate, tert-butyl peroxybenzoate, lauroyl peroxide, di- tert-butyl peroxide 98 %, benzoyl peroxide, di-tertiary amyl peroxide, 1,1-bis(tert-amylperoxy)cyclohexane, dicumyl peroxide, tert-butyl hydroperoxide, tert-butyl peracetate, and azo-bis-isobutyronitrile.
The first fluid medium can be selected from aromatic hydrocarbons and aliphatic esters.
The resultant mixture is heated at a temperature in the range of 90 °C to 150 °C to obtain an acrylic polyol component having viscosity in the range of 500 cps to 5000 cps at 60 % solid concentration.
In one embodiment, at least one aceto-acetate component, in an amount in the range of 10 wt% to 30 wt%, is mixed with the hydroxyl acrylate monomer and the acrylate monomer.
In another embodiment, at least one vinylated aromatic component selected from the group consisting of styrene, vinyltoluene, and methylstyrene is mixed with the hydroxyl acrylate monomer and the acrylate monomer.
The acrylic polyol component is then mixed with a polyolefinic component having GPC average molecular weight in the range of 3,000 to 30,000, and an acid value in the range of 30 mg KOH/g to 100 mg KOH/g, and heated at a temperature in the range of 120 °C to170 °C, in the presence of a second fluid medium, to obtain a polymeric binder composition. The polymeric binder composition is characterized by having hydroxyl value in the range of 30 mg KOH/g to 180 mg KOH/g, acid value in the range of 2 mg KOH/g to 15 mg KOH/g, and viscosity in the range 500 cps to 5000 cps at 60 % solid concentration.
The polyolefinic component can be selected from the group consisting of linear polyethylene, branched polyethylene, ethylene copolymer, polypropylene, and propylene copolymer. In one embodiment, polyolefinic component further comprises at least one carbonyl functional group.
The second fluid medium can be selected from aromatic hydrocarbons and aliphatic esters.
A pre-determined amount of at least one curing agent, and a pre-determined amount of at least one third fluid medium is mixed to the polymeric binder composition to obtain the anti-graffiti coating composition.
Alternatively, in one embodiment of the present disclosure, at least one hydroxy acrylate monomer, at least one acrylate monomer, at least one free radical initiator, a polyolefinic component having GPC average molecular weight in the range of 3,000 to 30,000, an acid value in the range of 30 mg KOH/g to 100 mg KOH/g, and at least one first fluid medium are mixed simultaneously and heated at a temperature in the range of 90 °C to 150 °C to obtain a polymeric binder composition having a viscosity in the range 500 cps to 5000 cps at 60 % solids concentration. A pre-determined amount of at least one curing agent, and a pre-determined amount of at least one second fluid medium is mixed to the polymeric binder composition to obtain the anti-graffiti coating composition.
The anti-graffiti coating composition is configured to provide a glossy and transparent coating having an initial gloss value in the range of 90 % to 95 % at 60 ° inclination, and a water beading contact angle >90°.
The at least one curing agent can be selected from the group consisting of poly isocyanate, melamine-formaldehyde, urea formaldehyde, unimolecular amines, unimolecular amides, unimolecular amido-amines, unimolecular imido-amines, polyamines, polyamides, polyamido-amines, and polyimido-amines.
In an embodiment, at least one catalyst, along with the curing agent and the third fluid medium is added to the polymeric binder composition to obtain the anti-graffiti coating composition.
The at least one catalyst can be selected from the group consisting of poly isocyanate, melamine-formaldehyde, and urea formaldehyde. The at least one catalyst can be selected from the group consisting of dibutyltin dilaurate, dibutyltin diacetate, titanium tetrabutoxide, 1,4-diazabicyclo[2,2,2]-octane, metal dionate complex, Co, Zn, Bi salts of isooctate, Co, Zn, Bi salts of 2-ethylhexoate, and Zn and Ti acetoacetate complexes. Typically, the metal dionate complex can be formed between by the interaction of Zn, Zr, Bi, Co, Mn, Al, and Ni, with 2,4-pentanedione.
The third fluid medium can be selected from aromatic hydrocarbons and aliphatic esters.
In one embodiment, a pigment, such as, TiO2 can be added to the polymeric binder composition at ambient temperature before, being mixed with the curing agent, to provide a pigmented coating.
Use of a polyolefinic component having an acid value in the range of 30 mg KOH/g to 100 mg KOH/g and GPC average molecular weight in the range of 3,000 to 30,000, is critical for obtain the anti-graffiti coating composition of the present disclosure. The polyolefinic component has a higher acid value as compared to the final anti-graffiti coating composition. The anti-graffiti coating composition of the present disclosure is prepared using low molecular weight polyolefin having high Tg and low surface energy, which imparts hardness, slip, mar and anti-graffiti properties to the anti-graffiti coating composition.
The present disclosure is further described in light of the following laboratory scale experiments which are set forth for illustration purpose only and not to be construed for limiting the scope of the disclosure. These laboratory scale experiments can be scaled up to industrial/commercial scale and the results obtained can be extrapolated to industrial/commercial scale.
Experimental details
Experiment 1: Preparation of the anti-graffiti coating composition in accordance with the present disclosure
23 g of hydroxy methyl methacrylate, 14 g of n-butyl acrylate, 21 g of n-butyl methacrylate, 4 g of methyl methacrylate, and 3 g of tert-butyl peroxybenzoate were blended and heated at 100 °C. 3 g of modified polyolefin (polyethylene having acid value 35 mg KOH/g) and 27 g of o-xylene was added at 150 °C to obtain the polymeric component. 25 g of Desmodur N75 and 0.1 g of dibutyltin dilaurate and 20 g of xylene was mixed with the polymeric component to obtain the anti-graffiti coating composition.
The acid value of the polyolefin (polyethylene) used was 35 mg KOH/g, whereas the acid value of the anti-graffiti coating composition was found to be 10 mg KOH/g. Further, the surface energy on a film formed by the application of the anti-graffiti coating composition (35 mN/m2) was lower as compared to that of the acrylic alone [40 mN/m2 (without the polyolefin)]. The anti-graffiti coating composition also exhibited an increase in the contact angle (85 °), , which is close to hydrophobicity. It is observed that the initial contact angle (water) of cured film of acrylic polyol with polyisocyanate is 75-79° and contact angle (water) of cured film of maleic anhydride modified polypropylene with polyisocyanate is 85-100°.The balance of the relative hydrophobicity and marginal hydrophilicity due to the residual acid value enhances the anti-graffiti (stain resistance, stain cleaning) properties on the dry film.
The anti-graffiti coating composition was applied on a metal panel and a glass plate, and was allowed to cure at ambient temperature for 7 days. Graffiti was applied on the dry and cured film using a permanent marker pen. The stain from the marker pen was easily removed with a dry cloth, without any damage to the film.
Experiment 2: Comparison of the differential surface energy and surface hardness
Studies were carried out to determine the effect of physical blending and reactor blending of the polyolefin and acrylate on differential surface energy and surface hardness and the results obtained are summarized in Table-1 below.
Table-1: Comparison of differential surface energy and surface hardness of the physical blend and reactor blend of polyolefin and acrylate
S. No. Sample Name Tg (°C) Tm (°C) ?H (J/g) ?H (J/g) (normalized w.r.t. 100 % A)
1 Modified low MW PP 100 % (A) Not visible (@10 °C/min);
29.32 (@20 °C/min); 157.64 40.89 40.89
2 12 % styrene containing copoly-acrylate polyol 100 % (B) 10.8 Amorphous N/A N/A
3 Physical blend of A (7 wt%) + B (93 wt%) (C) 26.1 159.99 28.04 400.57
4 Reactor blend of A (7 wt%) + B (93 wt%) (D) 15.6 147.58 0.645 9.21

It is clearly seen from Table-1 that (D) exhibited an incremental increase in Tg, whereas in case of (C) an abrupt increase of about 10 °C was observed. Further, (C) facilitated the polyolefinic segment to crystalize and re-melt, which resulted in sharp increase in the normalized ?H, whereas in case of (D), both the Tm and the ?H value were significantly low and the resulting material is almost amorphous. Hence, it was confirmed that (D) is not a simple composition achieved by mixing (A) and (B), but was a different product obtained by the reactor blending of the low MW polyolefin with the acrylate component.
It was observed that the enthalpy of the crystalline melting of (C) increased by about 1.5 times whereas a decrease in the crystallinity of (D) was observed. The reduction in the crystallinity plays a significant role in the clarity and gloss of the film formed using the anti-graffiti coating composition of the present disclosure.
The present disclosure provides an anti-graffiti coating composition comprising low molecular weight polyolefin having high Tg and low surface energy, which imparts improved hardness, slip, mar and anti-graffiti properties as compared to that of the commercially available anti-graffiti coating compositions. Also, graffiti on the dry and cured film of the anti-graffiti coating composition can be easily removed without any film damage. A pigment can be added to the anti-graffiti coating composition to obtain a pigmented product, which can be used to paint decorative or industrial surfaces. Further, the anti-graffiti coating composition is comparatively inexpensive as compared to the commercially available anti-graffiti coating compositions as summarized in Table-2 below.
Table-2: Comparison of the price of the anti-graffiti coating composition of the present disclosure and the commercially available compositions
Type of polymer Polyolefin modified Acrylic polyol Acrylic poly siloxane Fluro-Acrylic polyol Silicone additive Fluoro additive
Approx. RMC/Kg 110 Rs 400-500 Rs 800-900 Rs 2000-3000 2000-3000

TECHNICAL ADVANCES AND ECONOMICAL SIGNIFICANCE
The present disclosure described herein above has several technical advantages including, but not limited to, the realization of an anti-graffiti coating composition that exhibits improved hardness, slip, mar and anti-graffiti properties. Further, the anti-graffiti coating composition is comparatively inexpensive as compared to the commercially available anti-graffiti coating compositions.
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.