A High Performance Coating Composition

Technical Field

The present invention relates to a high performance coating composition, methods of preparing the same and uses of the composition.

Background

Dendritic polymers are polymers with hyperbranched structures which can comprise a high number of reactive functional groups exposed at the peripheral edges of the Dendritic polymer. Dendritic polymers mimic the hydrodynamic volumes of spheres, and as such, they can be used to provide coatings of high molecular weights whilst maintaining relatively low viscosity.

As a result, coatings prepared from dendritic polymers have gained traction and popularity in the field of protective coatings. Due to the unique structure of dendritic polymers, the coatings display a variety of desirable traits, such as, high pencil hardness, chemical resistance, solvent resistance and water resistance. Accordingly, such coatings are capable of providing good protection for a surface from damage by elements such as water, snow, ice, heat, dirt, smog, organic waste matter, chemical attacks and acid precipitation.

Accordingly, much effort has been expended to provide improved dendritic polymer-based protective coatings, not least to widen the scope of possible applications of such coatings but also to improve the utility of current applications. Accordingly, it is an object of the present invention to provide such a dendritic polymer-based coating, wherein the coating displays superior physical performance, such as improved pencil hardness and scratch resistance, and improved chemical performance, such as improved water resistance and solvent resistance compared to conventional dendrimer-based coatings. It is also an object of the present invention to provide a coating having improved adhesion properties in addition to the above technical improvements .

In particular, it is further an object of the present invention to provide a novel polymer composition that can be used to prepare high performance coatings possessing improved adhesion properties, improved pencil hardness and chemical resistance relative to conventional protective coatings.

Furthermore, due to the high functionality and reactivity of dendritic polymers, yet another technical problem occurs when having to apply more than one layer of coating. In particular, when more than one layer of coating is required to be applied, a problem arises where the applied layer of coating becomes dry and/or cures too fast and renders it unfeasible to apply another layer of coating thereon. The time period between applying a first coating layer to the time when the applied layer becomes unworkable for application of another layer of coating is also known as the "open time".

Accordingly, it is further an object of the present invention to provide a novel dendritic polymer composition, which can alter the "open time" and in particular to prolong the "open time" of the coating and thereby broaden the application window. Summary

In a first aspect, there is provided a coating composition, comprising at least one dendritic polymer, at least one silicon compound, and at least one cross - linker, wherein the silicon compound is selected from the group consisting of siloxanes and SiX ₄ ; wherein X in each instance is independently selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, heterocycloalkyl , aryl, aralkyl, heteroaryl, halide, aminoalkyl, ethers, -OR ¹ , and -OfCOlR ¹ , wherein each instance of R ¹ is independently selected from hydrogen, alkyl, alkyl, alkenyl, alkynyl, cycloalkyl, heterocycloalkyl, aryl, aralkyl, and heteroaryl; wherein at least one X is halide, -OR ¹ , or -OCCOjR ¹ ; and wherein the silicon compound is present in an amount between about 0.1% to about 20% by weight of the coating composition.

In a second aspect, there is provided a coating composition, comprising at least one hyperbranched polyester, vinyltrimethoxysilane , and a cross-linker selected from the group consisting of hexamethylene diisocyanate, dimers of hexamethylene diisocyanate, biuret dimers of hexamethylene diisocyanate, isocyanurate trimers of hexamethylene diisocyanate, and mixtures thereof .

In a third aspect, there is provided a coating composition comprising (a) one or more dendritic polymers; (b) a functionalizxng agent comprising at least one reactive group capable of bonding with an inorganic substrate and at least one organofunctional group capable of coupling with the dendritic polymer; and (c) one or more cross-linkers .

Advantageously, it has been surprisingly found that the disclosed coating compositions are capable of preparing coatings of unexpectedly high coating performance. For example, in one technical improvement, the disclosed coatings demonstrate superior pencil hardness and scratch resistance relative to coatings which do not comprise the above combination of dendritic polymers, functionalizing agent and cross-linkers. In another technical improvement _/ the coating displays improved chemical resistance, such as resistance to organic solvents, bases and water, compared to a coating that does not comprise the above defined combination of elements. In another technical improvement, the coating surprisingly retained good flexibility even with the improved hardness.

As an added advantage, it is also been surprisingly found that the coatings formed from the disclosed coating compositions possess a glossy and smooth surface appearance that is aesthetically pleasing. A pleasing aesthetical appearance is understandably important with respect to numerous commercial applications of the coatings .

Additionally, the coating compositions described herein may advantageously increase the open time/pot life of the one or two component coating composition. In particular, it has been found that the disclosed polymer compositions in a coating composition experienced longer open time/pot life when compared with known one and two component coating compositions. Without being bound by theory, the increase in pot life may be due to the presence of the functionalizing agent, e.g., silicon compound, which in combination with the dendritic polymer, delays the additional cross-linking processes during curing and provides the coating film with a longer open time. In certain instances, the open time/pot life can be extended by up to 50%-300% longer than traditional coating compositions. Such increased open time/pot life can be realized with as little as 0.1 to 2% by weight of the functionalizing agent, e.g., silicon compound.

Without being bound by theory, it is further postulated that the improved coating performance of the coatings that comprise the silane compound may be due to the silane compounds having reactive hydrolysable groups, such as methoxy groups (-O e) . In particular, the methpxy groups may react with H ₂ 0 to form silanol groups (-Si(OH) ₃ ), which are able to crosslink with the hydroxyl dendritic polymer to form a -Si-O-Si- network, thereby forming a substantially hydrophobic layer on top surface of the coating. This hydrophobic layer has a denser cross-linking density and may delay or prevent to a certain extent, the permeation of moisture as the coating composition is cured, thereby resulting in higher pencil hardness and longer open time of the moisture cured coating.

Further advantageously, the disclosed coating composition also demonstrates improved coating adhesion properties, in particular, to non-organic substrates such as glass, metal, or ceramic. This can be attributed to the functionalizing agent, which comprises one or more reactive groups capable of attaching themselves to an inorganic substrate. Advantageously, this improves the overall adhesiveness of the coating composition.

In a fourth aspect, there is provided a process for preparing a coating composition, said process comprising the step of introducing: (a) one or more dendritic polymers; (b) a functionalizing agent comprising at least one reactive group capable of bonding with an inorganic substrate and at least one organofunctional group capable of coupling with said dendritic polymers; and (c) one or more cross- linkers ; to form said coating composition, wherein the introducing step comprises a mixing step.

In one embodiment, the coating composition may be subjected to curing under increased temperature, ultra- violet radiation or a combination of both, in the presence of one or more catalysts, to form a highly cross-linked, high performance coating as defined above. The technical advantages are as described above for the coating composition of the first aspect.

In a fifth aspect, there is provided a process for preparing a coating, said process comprising the step of curing the coating composition defined above.

In one embodiment, there is provided a coating composition comprising (a) one or more dendritic polymers; (b) a functionalizing agent comprising at least one reactive group capable of bonding with an inorganic substrate and at least one organofunctional group capable of coupling with the dendritic polymer; (c) one or more blocked cross- linkers ; and one or more catalysts.

In one embodiment, there is provided a coating composition comprising a first and a second component, the first component comprising: (i) one or more dendritic polymers; (ii) a functionalizing agent comprising at least one reactive group capable of bonding with an inorganic substrate and at least one organofunctional group capable of coupling with the dendritic polymer; and the second component comprising one or more cross - linkers; wherein said first and second component are mixed to form said coating composition.

In one embodiment, the coating composition may be subjected to curing to form a coating after mixing the first and second components. The curing may comprise an application of heat, ultra-violet (UV) radiation, electron-beam (EB) radiation or a combination thereof. Definitions

The following words and terms used herein shall have the meaning indicated:

As used herein, the term "dendritic polymer" refers to a three-dimensional macromolecular material comprising a polyvalent core that is covalently bonded to a plurality of dendrons (or tree-like structures) . The term "dendron" means a tree-like structure having multiple branching layers (or "generations") that emanates from a focal point, such as a polyvalent core. Each succeeding branching layer or generation of a dendron extends from the prior generation, and each branching layer or generation in the dendron has one or more terminal reactive sites (or "terminal functional groups") from which the succeeding generation (if any) may extend, or in the case of the last generation, which may provide a terminal functional group on ^* the dendritic polymer. Dendritic polymers generally have a large number of terminal functional groups, lack entanglements, and have a low hydrodynamic volume. Further, as used herein, the term "dendritic polymer" includes both "dendrimers" and "hyperbranched polymers". In certain embodiments, the term "dendritic polymer" includes solely hyperbranched polymers. As used herein, the term "dendrimer" refers to a dendritic polymer having a symmetrical globular shape that results from a controlled process giving an essentially monodisperse molecular weight distribution. As used herein, the term "hyperbranched polymer" refers to a dendritic polymer having a certain degree of asymmetry and a polydisperse molecular weight distribution. In certain instances, the hyperbranched polymer has a globular shape . Hyperbranched polymers may be exemplified by those marketed by Perstorp under the Trademarks Boltorn H20™, Boltorn H30™, Boltorn H40™, etc.

The term "tack- free time", as used in the context of the present specification, refers broadly to the time taken for an applied coating to reach a physical state such that dry materials cannot be made to adhere to the coating surface. Tack- free time is typically measured through a standard measurement procedure known as the Zapon tack test, wherein a predetermined weight (usally 250 grams) is placed on a strip of aluminum, foil resting over the coating to be tested. The weight is removed from the aluminum after 5 seconds. The amount of time taken for the aluminum foil to dissociate from the coating is then measured. If the time taken for the aluminum foil to dissociate with the coating is 5 seconds or less, the coating is said to be tack- free.

The word "substantially" does not exclude "completely" e.g. a composition which is "substantially free" from Y may be completely free from Y. Where necessary, the word "substantially" may be omitted from the definition of the invention.

Unless specified otherwise, the terms "comprising", and "comprise", and grammatical variants thereof, are intended to represent "open" or "inclusive" language such that they include recited elements but also permit inclusion of additional, unrecited elements.

As used herein, the term "about", in the context of concentrations of components of the formulations, typically means +/- 5% of the stated value, more typically +/- 4% of the stated value, more typically +/- 3% of the stated value, more typically, +/- 2% of the stated value, even more typically +/- 1% of the stated value, and even more typically +/- 0.5% of the stated value .

Throughout this disclosure, certain embodiments may be disclosed in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the disclosed ranges. Accordingly, the description of a range should be considered to have specifically disclosed all the possible sub-ranges as well as individual numerical values within that range. For example, description of a range such as from 1 to 6 should be considered to have specifically disclosed sub-ranges such as from 1 to 3 , from 1 to 4 , from 1 to 5, from 2 to 4 , from 2 to 6, from 3 to 6 etc., as well as individual numbers within that range, for example, 1, 2, 3, 4, 5, and 6. This applies regardless of the breadth of the range.

Disclosure of Optional Embodiments

Exemplary, non-limiting embodiments of the above disclosed coating composition in accordance with the first aspect will now be disclosed.

The dendritic polymers may be selected from any suitable hyperbranched polymer having reactive peripheral functional groups capable of reacting with the disclosed functionalizing agents and cross-linkers. Exemplary dendritic polymers may include, but are not limited to, hydroxyl-terminated polyester, carboxyl-terminated polyester, acrylate-terminated polyester, blends of such polyesters and co-polymers thereof.

In one embodiment, the dendritic polymer is a hydroxyl terminated polyester. The hydroxyl terminated dendritic polymer may have from about 16 to about 128 theoretical peripheral hydroxyl groups per molecule of dendritic polymer. In another embodiment, the dendritic polymer may have from about 20 to about 80 peripheral hydroxyl grou s. In certain embodiments, the dendritic polymer has 16, 32, 64, or 128 theoretical hydroxyl groups. In certain embodiments, the dendritic polymer has 32 or 64 theoretical hydroxyl groups. In certain embodiments, the dendritic polymer has 32 theoretical hydroxyl groups. In certain embodiments, the dendritic polymer has 64 theoretical hydroxyl groups. In another embodiment, the dendritic polymer is a second generation dendritic polymer having a theoretical number of 16 peripheral hydroxyl groups per polymer molecule. Preferably, the dendritic polymer is a third or fourth generation dendritic polymer having theoretical peripheral functionality of about 32 to 64. It is generally preferred to have a peripheral functionality of above 32, in order to provide sufficient peripheral functional groups for reaction with cross linkers and other cross-linkable components such as the functionalizing agents.

In one embodiment, the dendritic polymer is selected from a polyester dendrimer, a polyamide dendrimer, a polyamine dendrimer, a polyether dendrimer, a polyurethane dendrimer, a polycarbonate dendrimer, and mixtures thereof .

In one embodiment, the dendritic polymer is selected from hyprebranched polyesters, a hyperbranched polyamide, a hyperbranched polyamine, a hyperbranched polyether, a hyperbranched polyurethane, a hyperbranched polycarbonate, and mixtures thereof.

In one embodiment, the dendritic polymer is a carboxyl- terminated polyester. In one embodiment, the dendritic polymer is an acrylate-terminated polyester.

In one embodiment, the dendritic polymer is a hydroxyl- terminated polyester, a carboxyl- terminated polyester, an acrylate-terminated polyester, and mixtures thereof .

In one embodiment, the dendritic polymer is a hyperbranched hydroxyl-terminated polyester, a hyperbranched carboxyl- terminated polyester, a hyperbranched acrylate-terminated polyester, and mixtures thereof .

In one embodiment, the dendritic polymer is sold under the Boltorn trademark available from Perstorp Plyols, such as Boltorn H10, Boltorn H20, Boltorn H30 and Boltorn H40 . In one embodiment, the dendritic polymer is Boltorn H30. In one embodiment, the dendritic polymer is Boltorn H40

In one embodiment, the functionalizing agent may comprise at least one reactive group capable of reacting with an inorganic compound and at least one organofunctional group capable of reacting with an organic compound, such as a peripheral functional group of a dendritic polymer.

In one embodiment, the functional!zing agent is a silicon compound selected from the group consisting of siloxanes and SiX ₄ ; wherein X in each instance is independently selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, heterocycloalkyl, aryl, aralkyl, heteroaryl, halide, aminoalkyl, ethers, -OR ¹ , and -OlCOlR ¹ , wherein each instance of R ¹ is independently selected from hydrogen, alkyl, alkyl, alkenyl, alkynyl, cycloalkyl, heterocycloalkyl, aryl, aralkyl, and heteroaryl; wherein at least one X is halide, -OR ¹ , or ^' -O (CO) R ¹ .

In certain embodiments, the silicon compound is SiX ₄ . The coating composition of claim 6, wherein at least two X independently in each instance is selected from the group consisting of halide, -OR ¹ , and or -OiCOjR ¹ .

In certain embodiments, the silicon compound is SiX ₄ , wherein at least two X independently in each instance is selected from the group consisting of -OR ¹ , and or - OtCOjR ¹ .

In certain embodiments, the silicon compound is Si(OR ¹ ) ₃ X.

In certain embodiments, the silicon compound is Si(OR ¹ ) ₃ X, wherein X is alkyl, alkenyl, alkynyl, cycloalkyl, heterocycloalkyl, aryl, aralkyl, heteroaryl, aminoalkyl, or ether. In certain embodiments, the silicon compound is Si(0R ¹ ) ₃ X, wherein X is alkyl.

In certain embodiments, the silicon compound and the cross-linker are not the same.

In one embodiment, the reactive group and the organofunctional group maybe the same compound or functional group.

In one embodiment, the reactive group may be an alkoxide having the general formula MA _n , wherein n is an integer from 3 to 4 ; M is an element selected from the group consisting of: Zirconium (Zr) , Aluminum (Al) , Titanium (Ti) , Tin (Sn) and Silicon (Si) ; and A is a halide or an (OR) group, wherein R is acetyl, a phenyl group or an alkyl group having 1 to 6 carbon atoms. In one embodiment, the alkyl group is selected from the group consisting of methoxy, and ethoxy. In one embodiment, the halide is selected from the group consisting of fluoride (F) , bromide (Br) , chloride (CI) and iodide (I) . In one embodiment, A is CI.

In one embodiment, the reactive group of the functionalizing agent is a siloxane. The siloxane functional group may have a general formula Si(OR) ₃ . The siloxane may be selected from the group consisting of: methoxy siloxane, ethoxy siloxane, acetoxy siloxane, chloro- siloxane and combinations thereof. In one embodiment, the siloxane functional group is methoxy siloxane, wherein (OR) is -OCH ₃ .

The organofunctional group of the functionalizing agent may be selected from the group consisting of: amine, amino, amine, hydroxyl, carboxyl, epoxide, methacrylate, mercaptan (SH) , alkyl, alkylene, vinyl, isocyanate, carbamate and combinations thereof. In one embodiment, the organofunctional group is alkyl. In another embodiment, the organofunctional group is amine.

In one embodiment, the functionalizing agent may be a siloxane having the general formula (I) : (Z ₃ -Si- (CH ₂ ) _n ) _m -X

wherein n is an integer ranging from 0 to 10; m is an integer ranging from 1 to 4 ;

Z is a reactive hydrolysable group selected from a halide or an (OR) group, wherein R is H, acetyl, a phenyl group or an alkyl group having 1 to 6 carbon atoms ; and

X is an organofunctional group selected from the group consisting of amino, amine, hydroxyl, carboxyl, epoxide, methacrylate, mercaptan (SH) , alkyl, isocyanate, carbamate and combinations thereof. In one embodiment, the alkyl group is selected from the group consisting of methoxy, and ethoxy. In one embodiment, the halide is selected from the group consisting of fluoride (F) , bromide (Br) , chloride (CI) and iodide (I) . In one embodiment, A is CI.

In another embodiment, the functionalizing agent may be a siloxane having the general formula (II) :

(Z ₃ -Si- (CH ₂ ) _n ) _m -Y-X

wherein Y is an organic group selected from the group consisting of: alkyl, ether, ketone or aldehyde; and wherein Z, n, m and X are as defined above. In one embodiment, Y is not -CH ₂ -.

In another embodiment, the siloxane can be a bifunctional organosilane, that is, having a general formula (III) :

(Z^s-Si- (CH ₂ ) _a -X- (CH ₂ ) _b -Si- (Z ² ) ₃ wherein X is as defined above;

(Z ¹ ) and (Z ² ) , being same or different, are hydrolysable groups selected from an (OR) group, wherein R is H, acetyl, a phenyl group or an alkyl group having 1 to 6 carbon atoms; and

a and b are integers, independently selected from 0 to 10. In one embodiment, the alkyl group is selected from the group consisting of methoxy, and ethoxy.

In one embodiment, the functionalizing agent is a bifunctional trimethoxysilyl aminosilane, that is, wherein X is amino and where (Z ² ) and (Z ¹ ) are methoxy.

In another embodiment, the functional!zing agent is a bifunctional organosilane possessing a reactive vinyl group and a hydrolysable inorganic tri-methoxysilyl group. In another embodiment, the functionalizing agent may be a bifunctional organosilane possessing a reactive secondary amine group and two hydrolysable inorganic tri- methoxysilyl group.

In another embodiment, the organosilane compound is a monofunctional trimethoxysilyl epoxysilane, wherein X is epoxy and (Z ² ) and (Z ¹ ) are methoxy.

The functionalizing agent may be present in an amount of at least about 0.01% by weight based on the total weight of the coating composition. In another embodiment, the functionalizing agent may be in an amount from about 0.01% to about 20% by weight based on the total weight of the coating composition. In yet another embodiment, the functional!zing agent may be present in an amount of from about 0.2% to about 2.0% by weight. In still another embodiment, the functionalizing agent may be in an amount of about 0.05%, about 0.1%, about 0.15%, about 0.25%, about 0.3%, about 0.35%, about 0.4%, about 0.45%, about 0.5%, about 0.55%, about 0.6%, about 0.65%, about 0.7%, about 0.75%, about 0.8wt%, about 0.85%, about 0.9%, about 0.95%, or about 1% by weight based on the total weight of the coating composition.

In another embodiment, the functionalizing agent may be present in an amount of about 3%, about 4%, about 5%, about 6%, about 7%, about 8%, about 9% or about 10% of the coating composition.

In certain embodiments, the silicon compound is present in an amount between about 0.01% to about 7% by weight of the coating composition. In certain embodiments, the silicon compound is present in an amount between about 0.01% to about 5% by weight of the coating composition.

In certain embodiments, the silicon compound is present is present in an amount between about 0.01% to about 2% by weight of the coating composition. In certain embodiments, the silicon compound is vinyltrimethoxysilane and vinyltrimethoxysilane is present in an amount between 0.1% and 20% by weight of the coating composition. In certain embodiments the vinyltrimethoxysilane is present in an amount between 0.1% to 10%, 0.1% to 5%, 0.1% to 4%, 0.1% to 3%, 0.1% to 2%, or 0.1% to 1% by weight of the coating composition. In certain embodiments the vinyltrimethoxysilane is present in an amount between 10% and 20%, 10% and 15%, or 15% and 20% by weight of the coating composition.

In certain embodiments, the silicon compound is vinyltrimethoxysilane and vinyltrimethoxysilane is present in an amount between 0.1% and 2% by weight of the coating composition.

In certain embodiments, the silicon compound is vinyltrimethoxysilane and vinyltrimethoxysilane is present in an amount between 10% and 20% by weight of the coating composition.

In certain embodiments, the silicon compound is present in an amount sufficient to extend the open time/pot life of the coating composition by at least about 20% to about 1,000%, about 50% to about 800%, about 50% to about 700%, about 50% to about 600%, about 50% to about 500%, about 50% to about 400%, about 50% to about 300%, about 50% to about 200%, about 50% to about 175%, about 50% to about 150%, about 50% to about 125%, or about 50% to about 100%.

In certain embodiments, the silicon compound is present in an amount sufficient to extend the pot life of the coating composition by at least about 50% when compared to the coating composition absent the silicon compound . In certain embodiments, the silicon compound is present in an amount sufficient to extend the pot life of the coating composition by at least about 100% when compared to the coating composition absent the silicon compound .

In certain embodiments, the silicon compound is selected from the group consisting of tetramethyl orthosilicate, tetraethyl orthosilicate, tetrapropyl orthosilicate, vinyltrimethoxysilane, vinyltriethoxysilane, bis (trimethoxysilylpropyl) amine, allyltrimethoxysilane, allyltriethoxysilane, 1,2- bis (trimethoxysilyl) ethane,

cyclohexyl (dimethoxy) methylsilane, γ- glycidoxypropyltrimethoxysilane, diethoxydimethylsilane, diethoxydiphenylsilane, diethoxy (methyl) phenylsilane, dimethoxydiphenylsilane, n-propyltriethoxysilane, triethoxy (isobutyl) silane, triethoxyphenylsilane , trimethoxyphenylsilane, 3- isocyanatopropyltrimethoxysilane , 3- isocyanatopropyltriethoxysilane, and N- (beta- aminoethyl) gamma-aminopropyltrimethoxysilane .

In certain embodiments, the silicon compound is selected from the group consisting of tetramethyl orthosilicate, tetraethyl orthosilicate, tetrapropyl orthosilicate, vinyltrimethoxysilane, vinyltriethoxysilane, bis (trimethoxysilylpropyl) amine, allyltrimethoxysilane, allyltriethoxysilane, 1,2- bis (trimethoxysilyl) ethane,

cyclohexyl (dimethoxy ) methylsilane, γ- glycidoxypropyltrimethoxysilane, diethoxydimethylsilane, diethoxydiphenylsilane, diethoxy (methyl) phenylsilane, dimethoxydiphenylsilane, n-propyltriethoxysilane, triethoxy (isobutyl) silane, triethoxyphenylsilane, trimethoxyphenylsilane, and N- (beta-aminoethyl) gamma- aminopropyltrimethoxysilane .

In certain embodiments, the silicon compound is vinyltrimethoxysilane or vinyltrimethoxysilane . In certain embodiments, the silicon compound is vinyltrimethoxysilane .

In certain embodiments, the silicon compound is selected from the group consisting of hexamethyldisiloxane, hexamethylcyclotrisiloxane, octamethyltrisiloxane, poly (dimethylsiloxane) , and octamethylcyclotetrasiloxane .

Advantageously, the functional!zing agent may help to improve the adhesion properties of a coating formed from the coating composition. In particular, the functionalizing agent may improve the ability of the formed coating to adhere to inorganic substrates, such as glass, metal or minerals. Further advantageously, the functionalizing agent may also act as cross -linkers to promote cross -linking between the dendritic polymers, thereby increasing the cross-linking density of the coating. As a result, the formed coatings may exhibit improved hardness, chemical and moisture resistance. Further advantageously, the functionalizing agent may also alter the "open time" of the coating film. In one embodiment, the functionalizing agent may prolong the coating film "open time" and broaden the application window during coating application process .

The disclosed coating composition may comprise one or more cross- linkers . Any cross-linker compound comprising a functional moiety capable of reacting with the peripheral reactive groups of the dendritic polymers and/or the functionalizing agents may be employed as a cross -linker in the coating composition. In one embodiment, the cross-linker is selected from the group consisting of isocyanates, blocked isocyanates, anhydrides, melamine formaldehyde resins , urea- formaldehyde resins, and epoxides.

In one embodiment, the cross- linker selected from the group consisting of isocyanante, blocked isocyanate, melamine formaldehyde, epoxy, carbodiimide, and azirdine; or mixtures thereof.

In one embodiment, the cross-linker may have a general formula R-N=C=0 , wherein R may be selected from substituted or non-substituted, aliphatic or aromatic alkyls, alkenyls, aryls and the like.

In another embodiment, the cross-linker may be a di- isocyanate having a general formula 0=C=N-Ri -R ₂ -N=C=0 , wherein Ri and R ₂ , being same or different, may be independently selected from substituted or non- substituted, aliphatic or aromatic, alkyls, alkenyls, aryls and the like.

In one embodiment, the cross-linker compound is a polyisocyanate . The polyisocyanates may be selected from the group of diisocyanates , tri-isocyanates , and dimers, biuret dimers , and isocyanaurate trimers of the aforementioned polyisocyanates, and mixtures thereof.

Polyisocyanates can exist in different oligimeric forms, such as dimers, biuret dimers, and isocyanurates . These polyisocyanates can be represented by the structures shown below, wherein R ¹ is as defined above.

Isocyanurate Trimer Biuret Dimer Uretidone/Dimer The polyisocyanate may be of the general formula wherein R ¹ is alkyl, alkenyl, alkynyl, cycloalky, heterocyclocalkyl, aryl, diaryl, dicycloalkyl, 5-6 membered heterocyclic compound optionally substituted with one or more of a halogen, oxygen, nitrogen, or C ₂ -Ci ₀ alkyl; and n is a whole number selected from 2-30; selected from 2-10, selected from 2-10; or selected from 3-7.

In one embodiment, R ¹ is selected from the group consisting of: Ci-C ₁₀ alkyl, Ci-Ci ₀ alkenyl, Ci-Ci ₀ alkynyl, C3-C7 cycloalkyl, C ₃ -C ₇ heterocycloalkyl , C ₆ -C ₁₂ dicycloalkyl, C ₆ -Ci ₄ aryl, C ₆ -C ₁₄ heteroaryl, triazines, and isocyanurate, each optionally substituted by Ci-Ci ₀ alkyl, halogen, or oxygen. In one embodiment, R ¹ may be selected from the group consisting of: phenyl, diphenyl, methylene diphenyl, cyclohexyl, dicyclohexyl , methylene dicyclohexyl , xylene, toluene, and substituted triazinane.

In specific embodiments, the polyisocyanate is selected from the group consisting of: diphenylmethane 4 , 4' -diisocyanate, toluene diisocyanate (TDI) , methylene diphenyl diisocyanate (MDI) , methylene bis-4,4' - isocyanatocyclohexane, 1, -cyclohexane diisocyanate, triphenylmethane-4 , 4' ,4'' , -triioscyanate, 4' 4- dicyclohexamethylene diisocyanate (H ₁₂ MDI) , xylene diisocyanate, p-phenyl diisocyanate (PPDI) , hexamethylene diisocyanate (HDI) , isophorone diisocyanate (IPDI) , trimethyl hexamethylene diisocyanate ^~ (TMDI) , tetramethylxylene diisocyanate, and dimers, biuret dimers, and isocyanaurate trimers of the aforementioned polyisocyanates, and/or mixtures thereof. In one embodiment, the polyisocyanate is a mixture comprising isocyanurate trimers of HDI and dimers of HDI. In one embodiment, prior to reaction with the dendritic polymer, the polyisocyanates may be modified to exhibit hydrophilicity. In one embodiment, the polyisocyanates may be ether-modified, polyether-modified or ionically modified to thereby exhibit hydrophilicity. Exemplary hydrophilic polyisocyanates may include those marketed by Bayer Material Science AG, under the Trademark Bayhydur ^® XP2547, Bayhydur ^® XP2655, Bayhydur ^® XP2759, Bayhydur ^® XP2487, Desmodur ^® N3300, Desmodur ^® N3390, Desmodur ^® N3400, Desmodur ^® Ν360Ό, etc.

The cross-linker may also be a blocked compound wherein its cross-linkable moiety is chemically reacted with a blocking agent to substantially prevent it from reacting with the dendritic polymers and/or the functionalizing agent. In one embodiment, the cross- linker can be a blocked isocyanate selected from the list disclosed above. The blocked isocyanate may be used in single component (IK) coating systems wherein the cross- linker is provided in admixture with the coating composition and does not require a separate mixing step prior to applying the composition as a coating onto a surface. In one embodiment, the blocked isocyanate may be freed for reaction via the application of heat. Blocked isocyanates are not used in two-part (2K) coating systems where the dendritic polymers, functionalizing agent and the cross-linkers are only mixed shortly before applying the composition as a coating onto a surface.

In another embodiment, the cross-linker may also be selected from melamine formaldehyde resins. In one embodiment, the melamine formaldehyde resin is a hexamethoxymethyl-melamine formaldehyde resin.

The weight ratio of dendritic polymer to cross - linker may be from about 10:1 to about 1:10. In one embodiment, the weight ratio of dendritic polymer to cross -linker may be about 9:1, about 8:1, about 7:1, about 6:1, about 5:1, about 4:1, about 3:1, about 2:1, about 1:1, about 1:2, about 1:3, about 1:4, about 1:5, i about 1:6, about 1:7, about 1:8 or about 1:9.

In one embodiment, the coating compositions can further include one or more additives selected from the group consisiting of a catalyst; a silane-based curing compound; a polyol; a sterically hindered amine light stabilizer; a non-dendritic polymer, a UV absorber; and a photoinitiator .

In one embodiment, the catalyst may be selected from organometallic compounds or tertiary amines. Exemplary catalysts may include a dibutyltin compound, such as dibutyltin dilaurate and dibutyltin diacetate, Triethylenediamine (TEDA) , Triethylamine (TEA),

Triethanolamine, N, N-dimethylethanolamine (DMEA) , N,N- dimethylpiperazine and N-ethylmorpholine . In another embodiment, the catalyst may be a strong acid or a weak acid, such as a sulfonic acid. Exemplary acid catalysts may include dodecylbenzyl sulfonic acid, p- toluenesulfonic acid, dinonylnapthalene disulphonic acid (DNNDSA) , dodecyl benzene sulphonic acid (DDBSA) , dinonylnapthalene monosulphonic acid (D SA) , phosphates such as alkyl acid phosphates, metal salts and carboxylic acids. In the embodiment where the cross-linkers used belong to the class of melamine and expoxy resins, acid catalysts are used. In the embodiment where the cross - linkers used belong to the class of isocyanates, organometallic compounds and tertiary amines are used as catalysts .

The coating composition may further comprise one or more non-dendritic polymers. The non-dendritic polymer may be selected from the group consisting of aliphatic polyester, cyclic polyester, polyurethane, cyclic aliphatic polyester, polyacrylate, polyester polyol, polyurethane polyol, polyacrylate polyol, polycarbonate, polycarbonate polyol , copolymers and blends thereof .

In one embodiment, the non-dendritic polymer is a polyurethane, such as an aliphatic polyurethane dispersion (PUD) . In another embodiment, the non- dendritic polymer is an aliphatic polyester diol. In yet another embodiment, the non-dendritic polymer may be a co-polymer comprising polyacrylate and a polyester polyol. In a ^" preferred embodiment, the non-dendritic polymer is PUD, which is selected for its good flexibility and good compatibility with a dendritic polymer. Advantageously, the presence of a non-dendritic polymer further improves properties such as water and chemical resistance of the coating composition.

The coating composition may further comprise nanoparticles dispersed through the bulk of the coating composition. While not limited to these uses, nanoparticles may be added to the coating composition to impart physical strength, improve wear resistance and durability, increase solids content, improve the ease of cleaning the coating, improve physical appearance, and provide protection against ultra violent (UV) degradation. In one embodiment, the nanoparticles may be metal oxide nanoparticles. Preferably, the nanoparticles are selected from oxides of aluminum and zinc.

Typically, when added into the coating composition, the average particle size of the nanoparticles ranges from about 1 nm to 500 nm. In another embodiment, these nanoparticles may be encapsulated within a polymer which has been suitably functionalized for compatibility with the dendritic polymers used .

The coating composition may further comprise one or more of the following: UV-absorbers , surfactants, organic solvents and stabilizers.

The coating composition may further comprise one or more types of acrylic functional monomers. The acrylic functional monomers may be integrally linked with the dendritic polymers via reaction with cross-linkers, to thereby attach acrylic functional groups onto the dendritic polymer. Advantageously, the presence of the terminal double bonds provided by the acrylic functional groups may aid formation of radicals upon exposure to UV radiation. Advantageously, this allows for UV curing of a coating formed from the disclosed coating composition.

The acrylic functional monomers may be added to the coating composition in an amount sufficient to cause about 10% to about 50% substitution of the functional groups on the dendritic polymer with acrylic functional groups. In one embodiment , the acrylic functional monomer is added in an amount sufficient to cause about 20%, about 30%, or about 40% substitution of the functional groups on the dendritic polymers with acrylic functional groups . Exemplary acrylic functional monomers may be selected from, but are not limited to, the group consisting of 2-hydroxyethylacrylate (HEA) , hydroxyl ethyl methacrylate (HE A) and glycidyl methacrylate (G A) and monomer blends thereof . Exemplary, non- limiting embodiments of the process for preparing a coating composition in accordance with the second aspect will now be disclosed.

The mixing step of the disclosed process may comprise a physical blending step. Physical blending may be performed by mechanical blending through mixers and/or blenders. The physical blending step may be undertaken at room temperature (i.e., cold blending) using a mechanical mixer. In one embodiment, the dendritic polymer may be functionalized with one or more hydrophilic functional groups prior to being physically blended with the functionalizing agent. The hydrophilic functional groups may be selected from the group consisting of: primary amino groups, secondary amino groups, tertiary amino groups, quaternary ammonium salt groups, an amide group, an aldehyde group, a carbonyl group, a carboxyl group, a carboxylate group, an ester group, a sulfonic acid group, phosphoric acid group and a hydroxyl group. In one embodiment, the hydrophilic functional group is a carboxyl group.

In another embodiment, the mixing step may comprise a step (dl) of chemically reacting the dendritic polymers with the functionalizing agent to increase cross- linking density of the coating composition.

The chemical reaction between the dendritic polymers and functionalizing agent can be described with reference to Fig. 1. In particular, the reaction step (dl) may comprise at least one surface modification step (dl) (i) wherein the functionalizing agent attaches itself to the dendritic polymer by having its reactive group react with a peripheral functional group of the dendritic polymer (not shown explicitly in Fig.l). By way of example, where the reactive group is amine and the dendritic polymer comprises hydroxyl functionality, amide bonds may be formed between the amine groups and the hydroxyl groups to thereby attach the functionalizing agent onto the dendritic polymer.

The surface modification step (dl) (i) may be followed by a de-alkylation step (dl) (ii) wherein the alkyl groups of the siloxane functional group are subsequently replaced by hydroxyl groups via addition of water and the removal of R(OH) groups. This is then followed by a condensation step (dl) (iii) wherein two or more de-alkylated siloxane groups undergo a condensation step to form -Si-O-Si- bonds between two or more dendritic polymers. The condensation reactions can be carried on for as long as required to allow sufficient cross-linking to occur to thereby form a densely cross- linked network of dendrimers . Each of steps (dl) (i) , (dl) (ii) and (dl) (iii) can be performed concurrently in the presence of a suitable catalyst, such as, dibutyltin dilaureate.

The mixing step of the disclosed process may further comprise a step (d2) of chemically reacting the dendritic polymers with said cross-linkers to increase cross- linking density of the coating composition. The reaction step (d2) may be carried out in the presence of one or more cross-linking catalysts.

The mixing step of the disclosed process may further comprise a step (d3) of chemically reacting the cross- linkers with the functionalizing agents to increase cross-linking density of said coating composition. The reaction step (d3) may be carried out in the presence of one or more catalysts . In one embodiment of the disclosed process, the disclosed mixing ste comprises one or more of the above defined steps (dl) , (d2) and (d3) , each step occurring independently and/or concurrently with each other.

The present disclosure further provides a process for preparing a coating, the coating being formed by curing a coating composition as defined above or by curing a coating composition obtained from the process described above. The curing may be selected from heat curing, UV curing, EB curing and/or combinations thereof. Where heat curing is used, the curing may be undertaken at a temperature of greater than 25°C. In one embodiment, the heat curing may be performed at temperatures up to 250°C. In another embodiment, for 2 coating systems, the curing step may be undertaken at temperatures ranging from about 20°C to about 100°C. In yet another embodiment, for IK coating systems, the curing step may be undertaken at about 60°C to about 160°C.

In one embodiment of the disclosed process, the functionalizing agent is coupled to the dendritic polymer either by direct bonding or through bonding via a cross- linker.

The disclosed coating composition may be used in either a one component (IK) or two component (2K) coating composition for forming a high performance coating. The coating can be water-dispersible or a solvent-based coating for application over a surface, depending on whether an organic solvent is used or water is used as the dissolution medium. It can be appreciated that where water is used as the dissolution medium, the dendritic polymers may be further functionalized with one or more hydrophilic ionic groups to impart the necessary polarity for dissolving or dispersing in water.

In certain embodiments, the coating composition consists of a two component coating composition, wherein the two component coating composition consists of a first component and a second component, wherein the first component comprises the dendritic polymer, the second component comprises the cross-linker, and wherein the first component or second component further comprises the silicon compound. In certain embodiments, the first component further comprises the silicon compound. In certain embodiments, the second component comprises the silicon compound. In certain embodiments, the first component or the second component further comprises a catalyst. In certain embodiments, the first component comprises the catalyst . In certain embodiments , the second component comprises the catalyst .

In another embodiment, where the dendritic polymer is functionalized with acrylate containing groups, the applied coating may also be cured via exposure to UV radiation. The use of temperature curing in combination with UV curing is also envisioned within the scope of the present invention. Brief Description of Drawings

The accompanying drawings illustrate a disclosed embodiment and serves to explain the principles of the disclosed embodiment. It is to be understood, however, that the drawings are designed for purposes of illustration only, and not as a definition of the limits of the invention.

Fig. 1 is a reaction scheme showing the reaction mechanisms between an exemplary functional!zing agent and a dendritic polymer. Fig. 2 is a reaction scheme showing the mechanism how a dendritic polymer that has been reacted with a functionalizing agent can possess adhesive properties. Detailed Description of Drawings

With reference to Fig. 2, there is shown a reaction scheme between a dendritic polymer and an exemplary functionalizing agent according to the present invention. The dendrimer may have hydroxyl functional groups, carboxyl functional groups, acrylate functional groups or a combination of such functional groups disposed at the peripheral edge of the dendritic polymer molecule. With reference to Fig. 1, for purposes of illustration without limitation, the shown dendrimer comprises hydroxyl functionality.

An exemplary functionalizing agent having a general formula (I) (Z ₃ -Si- (CH ₂ ) _n ) _m -X is reacted with the dendrimer in the presence of a catalyst. The organofunctional X group reacts with the hydroxyl functional groups of the dendritic polymer to thereby attach the reactive, hydrolysable moieties -SiZ ₃ onto the dendrimer. By way of example, X can be a amino group and forms an amide linkage (-NHCO-)with the dendrimer.

The surface modified dendrimer is then de-alkylated in the presence of water to substitute the reactive, hydrolysable moieties -SiZ ₃ with -Si(OH) ₃ groups. Thereafter, the de-alkylated dendrimers undergo condensation reactions in the presence of a catalyst to form -Si-O-Si- bonds, linking one dendrimer molecule to another dendrimer molecule. The condensation reactions may be proceeded to an extent until a densely cross- linked dendrimer is formed. The pendant -OH groups of the siloxane moiety, being substantially polar in nature, can strong electrostatic bonds with an adjacent surface, thereby imparting an adhesive property to the coating composition.

Examples

Non- limiting examples of the invention will be further described in greater detail by reference to specific Examples, which should not be construed as in any way limiting the scope of the invention.

Materials used

Below is a list of the raw materials used in the following Examples. The commercial names (in bold) of the following raw chemicals will be used in the Examples for convenience .

1. Dendritic polymer with theoretically 64 peripheral hydroxyl groups, having a molecular weight of about 5100 g/mol solid, OH value 470-500, ("Boltorn H40") procured from Perstorp Singapore Pte Ltd.

2. Dendritic polyester polyol, with OH equivalent weight of about 200-300 and solid content of about 70%, ("PE-164-70D") procured from Nanovere Technologies, Michigan, United States of America.

3. A low viscosity, solvent-free, polyfunctional aliphatic polyisocyanate resin based on hexamethylene diisocyanate (HDI) , with NCO equivalent weight of 183, ("Desmodur N3600") procured from Bayer MaterialScience AG, Germany.

4. Isophorone diisocyanate (IPDI) ("Desmodur N4470") procured from Bayer MaterialScience AG, Germany. 5. A vinyl functional silane ("Silquest A- 171*"), a epoxy functional silane ^' ("Silquest A-187°"), a secondary aminofunctional bis -silane ("Silquest A- 1170 ^s ") procured from Momentive Performance Materials, Ohio, United States of America.

6. Pure aliphatic polyurethane dispersion ("PUD 163P") procured from Nipsea Technologies,. Singapore, having solids content: 33.8%; Viscosity: 35.5 cps ; pH: 7.87; Mw = 39673, and Mn = 9747.

Testing Methods

In the following Examples, the following industrially recognized testing methods are used to characterize the coatings: · Adhesion (1mm X 1mm) : ASTM D3359;

• Impact (as measured in Inch (in) .pounds (lb) (direct) , in. lb) : ASTM D2794;

• Pencil Hardness (Break/Scratch): ASTM D3363;

Examples 1(a) to 1(e)

Preparation of coating composition

A one-component (IK) coating composition was prepared comprising the components provided in Table 1 below.

Table 1

Solvent (butyl acetate/propylene 51.9 glycol methyl ether acetate (PMA) )

Catalyst (Dibutyltin Dilaurate

0.1

(DBTDL) )

Additive (BYK ^® 331/EnviroGem AD01) 1

UV Stabilizer (Tinuvin 384-2) 1

Additive (p-toluenesulfonyl 1

isocyanate (PTSI) )

Crosslinker (HDI/IPDI combination) 40

Total 100.00

Thereafter, a vinyl functional silane, Silquest A- 171°, was loaded in varying amounts into the IK coating composition to study the synthetic effect of the silane material in the dendritic polymer coating formulation.

Table 2 below shows the amounts of silane dosage levels in each Example.

Table 2

Example 2

Characterization of coating composition

The IK moisture curable coating compositions from Examples 1(a) to 1(e) were dried at room temperature for 48 hours. The dry film appearance of the IK moisture cured systems was clear and glossy. Using the pencil-hardness test, the moisture cured coating of Example 1(e), i.e. 0 wt% of the silane compound, possessed a scratch hardness of H and a break hardness of 2H. When 0.25 wt% of the silane compound was loaded, the break hardness doubled to 4H. When 2 wt% of the silane compound was loaded, i.e., in Example 1(a), the break hardness increased to 5H.

Additionally, the presence of the silane compound in the composition improved the adhesion of the coating to a substrate and delayed film drying time. The composition is thus more flexible in a sense that it is possible to apply more than one layer of the coating to a relatively larger area because the open time of the applied coating has been substantially lengthened.

Table 3 below summarizes the performance results of the moisture cured coatings.

Table 3

Without being bound by theory, it is postulated that the improved coating performance of the coatings that comprise the silane compound is due to silane compounds having reactive hydrolysable groups, such as methoxy groups (-OMe) . The methoxy groups react with H ₂ 0 to form silanol groups (-Si(OH) ₃ ), which are able to cross-link with the hydroxyl dendritic polymer to form a -Si-O-Si- network, thereby forming a hydrophobic layer on top of the clear coating. This hydrophobic layer has a denser cross-linking density and it is further postulated that this hydrophobic layer delays, or prevents to a certain extent, the permeation of moisture as the coating composition is cured, thereby resulting in higher pencil hardness and longer open time of the IK moisture cured system.

Examples 3 (a) to 3 (c)

Preparation of 2K coating composition

A two-component (2K) coating composition was prepared comprising the components provided in Table 4 below. The two components are termed "Side A" and "Side B" .

Table 4

Thereafter, a vinyl functional silane, Silquest A- 171°, was loaded in varying amounts into the 2K coating composition to study the effects of the silane compound in the dendritic polymer coating formulation.

Table 5 below shows the amounts of silane dosage levels in each Example.

Table 5

Example 4

Characterization of coating composition

The 2K coating compositions from Examples 3(a) to 3(c) were dried at 65°C for 45 minutes, followed by overnight post drying at room temperature. The dry film appearance of the 2K compositions was clear and glossy.

Using the pencil-hardness test, the 2K composition of Example 3(c), i.e., having no silane compound, possessed a scratch hardness of only 2H and a break hardness of 3H. When a small amount (0.5 wt%) of silane was added to the coating composition, i.e. Example 3(b), the break hardness greatly increased from 3H to 5H.

Additionally, the presence of silane in the composition improved adhesio to the substrate and delayed film drying time from 25 minutes to 40 minutes, which confers on the coating greater flexibility. Further, the coating composition possess improved flow properties, enhancing its ability to be formed into a coating film. The formed coating film also has an even smooth surface. Additionally, the dry coating film appears glossier and possesses a higher degree of a distinctiveness of image (DOI) .

Even further, without being bound by theory, it is postulated that the reactive vinyl groups of the silane increased the cross-linking density of the dry film when exposed to UV light.

Table 6 below summarizes the results of the coatings.

Table 6

Example 5a

Preparation of water dispersible dendritic polymer blend

186.3 g of Boltorn H40 and 93.1 g of MP are mixed in a 1L reactor. The mixture is heated up to 90 °C until all the Boltorn H40 are melted and a homogenous solution is obtained. 17.9 g of maleic anhydride is then added to the polymer solution and the temperature is adjusted to 100°C and maintained for another 60 minutes. Thereafter, the polymer solution is cooled to 65 °C, and followed by the addition of 22.2g of TEA and 180.4g of de-ionized water. The solution is then stirred for another 15 minutes . The resulting product is cooled to room temperature (approx. 25°C) and filtered with a 25 μτ filter cloth. The filtered product is a milky light reddish solution with the solid content of 52.46% and with a viscosity of 75.5 cps, a pH value of 7.78. lOg of the filtered product is then taken and further blended with 16.56 g of substantially pure PUD 163P at room temperature to give a dendritic polymer/PUD 163P polymer blend, which is a light milky solution with a solids content of 40%, Ew=803 mg KOH/g and pH=7.35.

Example 5b

Preparation of an aqueous dispersible 2K polyurethane (PU) coating composition

A two-component (2K) aqueous dispersible PU coating composition comprising a Side A and Side B is prepared in this Example. Side A comprises the water dispersible dendritic polymer blend (obtained from Example 5a) ; whereas Side B comprisesan isocyanate (HDI) . Table 7 shows the composition of each of Side A and Side B.

Additionally, 0-1% silane (Silquest A-187) was loading into the 2K PU coating composition to study the synthetic effect of silane material in the 2K coating composition.

Table 7

Side B

Bayhydur XP2547™ 22.56

Total 100

Side A is blended with Side B to form the 2K aqueous dispersible coating composition.

Example 5 (c)

Characterization of coating composition

The 2K aqueous dispersible PU coating composition from Example 5(b) was dried at 85°C for 2 hours, followed by overnight post-drying at room temperature.

Using the pencil-hardness test, it was found that the 2K PU system (without addition of a silane compound) displayed a scratch hardness of 2-3H and a break hardness of 3H. After adding 1% silane (Silquest A- 187) , both the scratch and break hardness dramatically increased from 2- 3H to 6H. (See Table 8)

Additionally, it was further found that the presence of silane in the formulation also increases the chemical resistance, as the total MEK Rubs increased from 471 cycles to 566 cycles (Also see Table 8) .

Table 8

Impact, In. lb >80 >80

Flexibility, .1/8' ' pass pass

100μ WFT on Glass

Pencil Hardness, 2H/3H 6H/6H

scratch/break

MEK Double Rub, 471 566

cycles

Example 6 (a)

Preparation of UV curable coating composition

This Example refers to an UV curable coating composition comprising an acrylate dendritic oligomer (CN 2304) about 95% t, UV photoinitiator (Irgacure 500) 5%wt.

Additionally, about 0-1% silane (Silquest A-1170) was loaded into the UV curable coating composition to study the synthetic effect of silane material in the dendritic polymer coating formulation.

Example 6 (b)

Characterization of coating composition

The UV curable coating composition from Example 6(a) was dried under UV light (Fusion Systems H bulb with 300 /cm) with Line speed 17 feet per min for irradiation.

Using the pencil -hardness test, it was found that the UV curable coating system (without addition of the silane compound) possessed a scratch hardness of 3H and a break hardness of 5H. After adding 1% silane (Silquest A-1170) , the break hardness increased to 6H. Applications

Disclosed herein is a coating composition comprising, inter alia, a dendritic polymer, a functionalizing agent having at least one reactive group and at least one organofunctional group, and cross- linkers. As described hereinabove, a coating prepared from the disclosed coating composition advantageously possesses improved coating properties, such as but not limited to, improved pencil hardness, increased adhesion to surface, improved flexibility for coating applications of wide surface area and enhanced solvent/water resistance. Therefore, the disclosed coatings can be applied to a wide variety of industrial applications requiring heavy-duty protective coatings. For example, the disclosed protective coatings foresee utility in industrial applications whereby equipment wear and tear is caused by prolonged exposure to abrasive forces. Furthermore, the disclosed coatings can be potentially employed in chemically corrosive environments due to its improved chemical/water resistance.

In addition to its improved physical strength and chemical resistance, it has been further demonstrated that the disclosed coating presents a smooth and glossy surface-, which is aesthetically pleasing and further expands its utility in commercial coating applications.

It will be apparent that various other modifications and adaptations of the invention will be apparent to the person skilled in the art after reading the foregoing disclosure without departing from the spirit and scope of the invention and it is intended that all such modifications and adaptations come within the scope of the appended claims.