High performance coatings for building panels”

Abstract

ABSTRACT “HIGH PERFORMANCE COATINGS FOR BUILDING PANELS” An anti-soiling article comprising a composition that includes a powder coating and a fluoro-containing repellent component, wherein the powder coating is formed from polymer resin, cross-linker and anionic fluorosurfactant that is different from the fluoro-containing repellent component; and wherein the anionic fluorosurfactant has a solids content from about 13% to about 15%. Fig. 1

Description

BACKGROUND

[0002] It is known that certain fluoro-carbon containing polymers and siloxane containingpolymers may be able to add dirt-resistant properties to paints and other solvent-based coatings.Previously, large quantities of such fluoro-carbon and siloxane containing polymers were requiredby the overall formulation - to obtain the desired dirt-resistant properties in the resulting coating.However, increasing the amount of fluoro-carbon and / or siloxane containing polymers in suchformulation inhibits the bonding strength of the coating to the underlying substrate or surface. Assuch, the resulting balance between the dirt-resistant properties of the exposed surface of thecoating and the coatings ability to adhere to the underlying substrate was undermined. Thus, thereexists a need to provide dirt-resistant coatings - specifically soil and dirt repellant coatings - thatachieve the desired exposed surface repellency, while not undermining the bond strength to theunderlying substrate. A powder coating system can benefit from such dirt-resistant properties, butunlike typical paints and coatings, it has additional constraints that it is desirable to be a solventfree system.

[0003] Additionally, microbial growth - including both fungus and bacteria - on indoor andoutdoor surfaces is a major environmental concern today affecting home, work and recreationalenvironments. Not only can such microbial growth be unsightly on exposed surfaces, it can destroyunderlying substrate materials if left untreated, causing severe damage to buildings and otherstructures and equipment. Over the past few years it has become increasingly apparent thatexposure to certain bacteria and fungi (or their spores) can seriously impact the health of humans,pets and other animals. Previous attempts at imparting antimicrobial properties to a building panelincluded applying an antimicrobial coating to a surface of a building material. However, suchprevious antimicrobial coatings required relatively large amounts of antimicrobial additives toimpart sufficient antimicrobial activity to the coating - thereby making such coatings expensiveas well as potentially interfering with aesthetic properties of the coating. Additionally, suchcoatings were required to be applied in a wet-state using some type of solvent - thereby eliminatingthe possibility of application to limited number of substrates. Thus, the need exists for a coatingthat can exhibit adequate antimicrobial performance with reduced amounts of antimicrobialadditive. There also exists the need for such antimicrobial coatings that may be applied withoutthe need of a solvent.BRIEF SUMMARY

[0004] The present invention is directed to an article comprising: a substrate; a polymeric powdercoating applied to the substrate, the polymeric powder coating having an upper surface opposite alower surface; and a top-coating applied to the upper surface of the polymeric powder coating, thetop-coating comprising a fluoro-containing repellent component that is present atop the uppersurface of the polymeric powder coating in an amount ranging from about 0.01 g / m2to about 4g / m2.

[0005] Other embodiments of the present invention include a method for forming a dirt-repellentarticle comprising: a) providing a substrate having a powder coating applied thereto, b) applyinga liquid-based coating composition to the powder coating, the liquid-based coating compositioncomprising a fluorosurfactant and a liquid carrier; and c) drying the liquid-based coatingcomposition, thereby driving off the liquid carrier to form the dirt-repellant article.

[0006] Other embodiments of the present invention include an article comprising a substrate; apowder coating applied to the substrate, the powder coating having an upper surface opposite alower surface and comprising a first fluorosurfactant; and a second fluorosurfactant that is differentfrom the first fluorosurfactant applied to the upper surface of the powder coating.

[0007] Other embodiments of the present invention include a method of forming a dirt repellantarticle comprising a) blending a mixture comprising liquid carrier, an anionic fluorosurfactant, anda polymer binder; b) subsequently drying the mixture to form a powder coating precursor mixturethat is substantially free of liquid carrier, c) followed by applying the powder coating precursormixture to a substrate; and d) subsequently curing the powder coating precursor mixture to formthe dirt repellant article, wherein the blending of step a) is performed at a temperature below themelt temperature of the anionic surfactant and the polymeric binder.

[0008] Other embodiments of the present invention include a method of forming a dirt repellantarticle comprising a) blending a mixture comprising liquid carrier, an anionic fluorosurfactant, anda polymer binder for a first time period followed by ceasing to blend the mixture for a second timeperiod to complete a blend cycle, b) repeating the blend cycle, c) drying the mixture to form apowder coating precursor mixture that is substantially free of liquid carrier, wherein the ratio ofthe first time period to the second time period ranges from about 1:1 to about 1:20.

[0009] In other embodiments, the present invention includes an antimicrobial building panelcomprising a substrate, a powder coating applied to the substrate, the powder coating comprisinga cross-linked polymeric binder and a blend of metal borate and a sulfur-containing benzimidazolecompound, wherein the metal borate and sulfur-containing benzimidazole compound are presentin a weight ratio ranging from about 75:1 to about 10:1.

[0010] Other embodiments of the present invention include an antimicrobial building panelcomprising a substrate, a powder coating applied to the substrate, the powder coating comprisinga cross-linked polymeric binder, a blend of metal borate and a sulfur-containing benzimidazolecompound, wherein the blend is present in a total amount ranging from about 5 parts by weight toabout 15 parts by weight based on 100 parts by weight of the powder coating.

[0011] Other embodiments of the present invention include a method of forming an antimicrobialbuilding panel comprising a) applying a powder coating precursor to a substrate; and b) curing thepowder coating precursor to form a cross-linked powder coating atop the substrate, wherein thepowder coating precursor comprises a polymer resin, cross-linker, a metal borate, and a sulfur-containing benzimidazole compound, and the powder composition has a solids content of about100%.

[0012] Other embodiments of the present invention include an antimicrobial coating compositioncomprising a polymeric resin, a cross-linker; and a blend of metal borate and a sulfur-containingbenzimidazole compound, wherein the metal borate and sulfur-containing benzimidazolecompound are present in a weight ratio ranging from about 75:1 to about 10:1.

[0013] Other embodiments of the present invention include an antimicrobial coating compositioncomprising a polymeric resin, a cross-linker; and a blend of metal borate and a sulfur-containingbenzimidazole compound, wherein the blend is present in a total amount ranging from about 5parts by weight to about 15 parts by weight based on 100 parts by weight of the antimicrobialcoating composition.

[0014] In other embodiments, the present invention includes an article comprising a substrate; apowder coating having an upper surface opposite a lower surface, the lower surface facing thesubstrate; and a cationic fluorosurfactant applied to the upper surface of the powder coating;wherein the powder coating is formed from a precursor comprising polymeric binder, cross-linker,anionic fluorosurfactant, and liquid-carrier.

[0015] Other embodiments of the present invention include an anti-soiling article comprising acomposition that includes a powder coating and a fluoro-containing repellent component, whereinthe powder coating is formed from polymer resin, cross-linker and anionic fluorosurfactant that isdifferent from the fluoro-containing repellent component.

[0016] An article comprising a powder coating applied to a substrate, the powder coating formedfrom a precursor comprising polymeric resin, cross-linker, and a blend of liquid carrier andfluorosurfactant.

[0017] Further areas of applicability of the present invention will become apparent from thedetailed description provided hereinafter. It should be understood that the detailed description andspecific examples, while indicating the preferred embodiment of the invention, are intended forpurposes of illustration only and are not intended to limit the scope of the invention.BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention will become more fully understood from the detailed description andthe accompanying drawings, wherein:

[0019] Figure 1 is perspective view of an article according to the present invention;

[0020] Figure 2 is a cross-sectional view of the article according to the present invention, the crosssectional view being along the II line set forth in Figure 1;

[0021] Figure 3 is a cross-sectional view of the article according to other embodiments of thepresent invention, the cross-sectional view being along the II line set forth in Figure 1;

[0022] Figure 4 is a building system comprising the article panel of the present invention; and

[0023] Figure 5 is a perspective view of a building system according to an alternative embodimentof the present invention; and

[0024] Figure 6 is a side profile view of a portion of the ceiling system 1 according to the presentinvention.DETAILED DESCRIPTION

[0025] The following description of the preferred embodiment(s) is merely exemplary in natureand is in no way intended to limit the invention, its application, or uses.

[0026] As used throughout, ranges are used as shorthand for describing each and every value thatis within the range. Any value within the range can be selected as the terminus of the range. Inaddition, all references cited herein are hereby incorporated by referenced in their entireties. Inthe event of a conflict in a definition in the present disclosure and that of a cited reference, thepresent disclosure controls.

[0027] Unless otherwise specified, all percentages and amounts expressed herein and elsewherein the specification should be understood to refer to percentages by weight. The amounts givenare based on the active weight of the material.

[0028] The description of illustrative embodiments according to principles of the present inventionis intended to be read in connection with the accompanying drawings, which are to be consideredpart of the entire written description. In the description of embodiments of the invention disclosedherein, any reference to direction or orientation is merely intended for convenience of descriptionand is not intended in any way to limit the scope of the present invention. Relative terms such as"lower," "upper," "horizontal," "vertical," "above," "below," "up," "down," "top," and "bottom"as well as derivatives thereof (e.g., "horizontally," "downwardly," "upwardly," etc.) should beconstrued to refer to the orientation as then described or as shown in the drawing under discussion.These relative terms are for convenience of description only and do not require that the apparatusbe constructed or operated in a particular orientation unless explicitly indicated as such.

[0029] Terms such as "attached," "affixed," "connected," "coupled," "interconnected," andsimilar refer to a relationship wherein structures are secured or attached to one another eitherdirectly or indirectly through intervening structures, as well as both movable or rigid attachmentsor relationships, unless expressly described otherwise. Moreover, the features and benefits of theinvention are illustrated by reference to the exemplified embodiments. Accordingly, the inventionexpressly should not be limited to such exemplary embodiments illustrating some possible nonlimiting combination of features that may exist alone or in other combinations of features; thescope of the invention being defined by the claims appended hereto.

[0030] Unless otherwise specified, all percentages and amounts expressed herein and elsewherein the specification should be understood to refer to percentages by weight. The amounts givenare based on the active weight of the material. According to the present application, the term"about" means + / - 5% of the reference value. According to the present application, the term"substantially free" less than about 0.1 wt. % based on the total of the referenced value.

[0031] The present invention is directed to an article having one or more dirt-repellant and / or antimicrobial surfaces present on a three-dimensional object, which is formed by applying one or morecoatings to a surface of a three-dimensional substrate. The substrate that forms the article of thepresent invention is not limited in any way other than it being a three-dimensional object that canretain its shape at temperatures up to about 210 °C for a period of at least 5 minutes. Non-limitingexamples of the article include building panels, air vents, doors, window covers (e.g., blinds), aswell as other surfaces of a car, train, or home, and the like. Although not limited to, the presentapplication will refer to the article as a building panel. Of course, the article of the presentapplication is not limited to building panels as the three-dimensional object.

[0032] Referring to Figure 1, the building panel 100 of the present invention may comprise a firstmajor surface 111 opposite a second major surface 112. The building panel 100 may furthercomprise a side surface 113 that extends between the first major surface 111 and the second majorsurface 112, thereby defining a perimeter of the building panel 100.

[0033] Referring to Figure 4, the present invention may further include a ceiling system 1comprising one or more of the building panels 100 installed in an interior space, whereby theinterior space comprises a plenary space 3 and an active room environment 2. The plenary space3 provides space for mechanical lines within a building (e.g., HVAC, plumbing, etc.). The activespace 2 provides room for the building occupants during normal intended use of the building (e.g.,in an office building, the active space would be occupied by offices containing computers, lamps,etc.). In the installed state, the first major surface 111 of the building panel 100 faces the activeroom environment 2 and the second major surface 112 of the building panel 100 faces the plenaryspace 3.

[0034] Referring now to Figures 1-3, the building panel 100 of the present invention may have apanel thickness t0 as measured from the first major surface 111 to the second major surface 112.The panel thickness t0 may range from about 5 mm to about 50 mm - including all values and subranges there-between. The building panel 100 may have a length ranging from about 30 cm to about 190 cm - including all values and sub-ranges there-between. The building panel 100 mayhave a width ranging from about 1 cm to about 121 cm - including all values and sub-ranges therebetween.

[0035] Referring now to Figures 2 and 3, the building panel 100 may comprise a substrate 120having an upper surface 121 opposite a lower surface 122 and a substrate side surface 123 thatextends between the upper surface 121 and the lower surface 122, thereby defining a perimeter ofthe substrate 120. The substrate 120 may have a substrate thickness t1 that extends from the uppersurface 121 to the lower surface 122 of the substrate 120. The substrate thickness t1 may rangefrom about 5 mm to about 50 mm - including all values and sub-ranges there-between.

[0036] The substrate 120 may be metallic, plastic, ceramic, a composite material, or a combinationthereof. In some embodiments, the metallic substrate may be an aluminum panel or a steel panel(including galvanized steel). According to some embodiments, the metallic substrate may beselected from materials such as iron, steel, aluminum, tin, and alloys thereof. The substrate 120may comprise any suitable dimensions suitable for building panel applications. The substrate maycomprise any suitable dimensions suitable for building panel applications.

[0037] The building panel 100 may comprise a first coating 130 having an upper surface 131opposite a lower surface 132 and a first coating side surface 133 that extends between the uppersurface 131 and the lower surface 132, thereby defining a perimeter of the first coating 130. Thefirst coating 130 may have a first coating thickness t2 that extends from the upper surface 131 tothe lower surface 132 of the first coating 130. The first coating thickness t2 may range from about50 μm to about 120 μm - including all values and sub-ranges there-between.

[0038] The first coating 130 may be applied directly to the upper surface 121 of the substrate 120.Specifically, the lower surface 132 of the first coating may be in contact and bonded to the uppersurface 121 of the substrate 120. In other embodiments, there may be one or more interveningcoatings or layers between the substrate 120 and the first coating 130 (not pictured).

[0039] The first coating 130 may be a powder coating comprising at least one polymeric binderand optionally one or more additives - as discussed further herein as "polymeric powder coating."The first coating 130 may also be referred to herein at an intermediate coating. The first coating130 may comprise surface imperfections 135 - such as depression, channels, pores, cracks, pinholing, etc. - that extend from the upper surface 131 toward the lower surface 132 of the firstcoating 130, thereby creating voids on the first coating 130. Specifically, the surface imperfections135 may extend to a depth ranging from about 1% to about 99% of the first coating thickness t2 asmeasured from the upper surface 131 toward the lower surface 132 of the first coating 130 -including all percentages and sub-ranges there-between.

[0040] The building panel 100 may comprise a second coating 140 having an upper surface 141opposite a lower surface 142 and a second coating side surface 143 that extends between the uppersurface 141 and the lower surface 142, thereby defining a perimeter of the second coating 140.The second coating 140 may be applied as liquid-based coating comprising at least onefluorosurfactant and / or fluoropolymer and liquid carrier - as discussed further herein. The secondcoating 140 may also be referred to herein as a "topcoat."

[0041] Referring now to Figure 2, the second coating 140 may be applied directly to the uppersurface 131 of the first coating 130 to form a continuous second coating 140. Specifically, thelower surface 142 of the second coating may be in contact and bonded to the upper surface 131 ofthe first coating 130. The first coating 130 may form the intermediate coating between the secondcoating 140 and the substrate 120.

[0042] The second coating 140 may comprise filling portions 145 that extend downward andbeyond the lower surface 142 of the second coating 140 thereby filling the voids created by thesurface imperfections 135 of the first coating 130 - as discussed further herein. The second coating140 may be substantially continuous, thereby forming a substantially continuous topcoat on thebuilding panel 100. The second coating 140 atop the first coating 130 may at least partially sealthe surface imperfections 135 that exist on the first coating 130 to provide a first major surface111 that is relatively smoother than the upper surface 131 of the first coating 130. According tothis embodiment, the first major surface 111 of the building panel 100 comprises the upper surface141 of the second coating 140 (and the second major surface 112 of the building panel 100 maycomprise the lower surface 122 of the substrate 120).

[0043] Referring now to Figure 3, in alternative embodiments, the second coating 140 may beapplied directly to the upper surface 131 of the first coating 130 to form a discontinuous secondcoating 140. Specifically, the lower surface 142 of the second coating may be in contact andbonded to the upper surface 131 of the first coating 130 and the first coating 130 may form a partialintermediate coating between the second coating 140 and the substrate 120. The term "partialintermediate coating" refers to first major surface 111 of the building panel comprising both theupper surface 141 of the discontinuous second coating 140 as well as portions of the upper surface131 of the first coating 130 exposed by the discontinuities of the second coating 140. The secondmajor surface 112 of the building panel 100 may comprise the lower surface 122 of the substrate120.

[0044] Regarding the composition of the first coating 130, the first coating 130 may be formedfrom a powder coating precursor, which comprises a high-solids mixture of a binder compositionand cross-linker (as referred to herein as "precursor" or "precursor mixture"). The precursormixture may be cured at an elevated temperature to form the fully cured powder coating, asdiscussed herein. According to the present invention, the terms "cure" and "cross-link" may beused interchangeably. In some embodiments, the precursor mixture has a solids content of 100%and is substantially free of solvent.

[0045] The binder composition may include a polymeric binder that is a polymeric resin capableof reacting with the cross-linker during curing to form a fully cured polymeric matrix composition.According to some embodiments, the polymeric resin of the present invention to have specificmaterial properties, including glass transition temperature, molecular weight, functionality, meltviscosity, and film formation and leveling properties. Without proper consideration to the abovereferences material properties, selecting the undesirable polymeric resin may result in acomposition that is unsuitable for powder coatings as the resulting precursor mixture may exhibitpoor shelf-life and inadequate flow properties during processing, and the resulting powder coatingmay exhibit inadequate film formation characteristics rendering the coating inoperable.

[0046] The polymeric resin should may comprise at least one polymeric composition having aglass transition temperature (Tg) that is greater than room temperature, preferably at least about20 °C. The polymeric resin may have a Tg that ranges from about 45 °C to about 80 °C. Thepolymeric resin should may comprise at least one polymeric composition having a glass transitiontemperature (Tg) that is greater than room temperature, preferably at least about 50 °C. Thepolymeric resin may have a Tg that is about 50 °C. The polymeric resin may have a Tg that isabout 60 °C. The polymeric resin may have a Tg that is about 70 °C. The polymeric resins mayhave a processing temperature that ranges from about 90 °C to about 150 °C. The term "processingtemperature" refers to the temperature of the polymeric resin that may be heated to withoutinitiating crosslinking between the polymeric resin and the cross-linker.

[0047] The binder composition may include a polymeric resin that can react with the cross-linkerduring curing, as discussed herein, thereby forming the fully cured matrix composition. Thepolymeric resin of the present invention may have specific material properties, including glasstransition temperature, molecular weight, functionality, melt viscosity, and film formation andleveling properties. Without proper consideration to the above references material properties,selecting the undesirable polymeric resin may result in a composition that is unsuitable for powdercoatings as the resulting precursor mixture may exhibit poor shelf-life and inadequate flowproperties during processing, and the resulting powder coating may exhibit inadequate filmformation characteristics rendering the coating inoperable.

[0048] Selecting a polymeric resin that has Tg that is too low may result in a precursor mixturethat cannot resist sintering and agglomeration during storage and / or shipping of the mixture,thereby degrading the shelf-life of the precursor mixture. Conversely, because powder coatingshave high solids contents, selecting a polymeric resin that has a Tg that is too high may result in aprecursor mixture that does not exhibit adequate flow during processing or leveling properties afterapplication, thereby resulting in an un-evenly applied powder coating composition. The Tg of apolymeric resin can be controlled through the selection of a number of parameters including, butnot limited to, molecular weight, type of polymeric backbone, and the degree of crystallinity, asdiscussed herein.

[0049] The flow properties of the polymeric resin are measured by a melt viscosity. At high solidscontent (preferably 100% solids, free of solvent), the obtaining a low melt viscosity is aconsideration to ensure maximum flow of the polymeric resin during processing. As a polymericresin is processed during mixing and curing (as discussed herein), the polymeric resin begins toreact with a curing agent, also referred to as a cross-linker, that is present in the precursor mixturethereby creating a significant increase in viscosity of the precursor mixture as it becomes the fullycured powder coating. Therefore, using a polymeric resin that exhibits a low melt viscosity mayhelp ensure that there is ample time for the precursor mixture to mix and flow through theprocessing unit (as discussed herein) before the precursor mixture has reacted a degree of crosslinking that approaches the fully cured powder coating. The melt viscosity of a polymeric resin isthe result of a number of factors that include: molecular weight, functionality, and type ofpolymeric backbone, as discussed herein. The specific melt viscosities of the polymeric resin andoverall precursor mixture will be discussed herein.

[0050] The polymeric resin may comprise at least one polymeric composition having a weightaverage (Mw) molecular weight that ranges from about 1,500 to 15,000 - including all sub-rangesand molecular weights there-between. The polymeric resin may have a weight average (Mw) thatranges from about 15,000 to 30,000 - including all sub-ranges and molecular weights therebetween. The molecular weight of the polymeric resin may impact the flexibility, impact strength,and processesability of the powder coating (i.e. melt viscosity). Polymeric resins having a greatermolecular weight (Mw) may exhibit greater melt viscosities as compared to lower weight (Mw)polymeric resins

[0051] The polymeric resin may have a molecular weight (Mw) ranging from about 1,500 to about15,000 has a polydispersity of about 1 - including all sub-ranges and molecular weights therebetween. Polydispersity is a ratio of weight average (Mw) molecular weight to number average(Mn) molecular weight of a polymeric composition. Having a polydispersity of about 1 mayensure that the physical properties of the resulting powder coating (i.e., flexibility, impact strength)are maximized without sacrificing a desired low melt viscosity of the precursor mixture duringprocessing. The low melt viscosity being suitable when processing at a high solids content(preferably solve-free) precursor mixture, as may be required for the powder coating according tosome embodiments of the present invention.

[0052] Forming a three-dimensional, cross-linked polymeric network that forms the powdercoating of the present invention may require that the polymeric resin comprises a polymer havingan average of at least two functional groups that are available to react with functional groupspresent on the cross-linker. In some embodiments, the polymeric resin may have an averagenumber of functional groups, the average ranging from 2 to 10 functional groups. In someembodiments, the polymeric resin may have a backbone that is linear or branched and theplacement of the functional groups will depend on the type of backbone of the polymeric resins.In some embodiments, the polymeric resin is a linear polymer having two to four functional groupspositioned at the terminal ends of the polymer. The functional groups of the polymeric resin maybe selected from hydroxyl groups, carboxylic acid groups, isocyanate groups, epoxy groups,acrylic groups and a combination thereof. In some embodiments, the functional groups of thepolymeric binder may be temporarily blocked as discussed herein.

[0053] According to some embodiments of the present invention, the polymeric resin maycomprise polymer having a backbone with moieties selected from ester groups, urethane groups,carbonate groups, epoxy groups and a combination thereof.

[0054] The polymeric resins and cross-linker react during curing to form a polymer matrix havinga crosslink density. The crosslink density of the cross-linked polymer matrix may be reflected bythe glass transition temperature of the cross-linked polymer matrix - which may range from about150 °C to about 300 °C - including all temperatures and sub-ranges there-between.

[0055] The binder composition may include a polymeric resin selected from polyester resin,polyurethane resin, epoxy resin, and polyester-urethane acrylate resin. Suitable polyester resinsmay be hydroxyl-functional (OH) or carboxyl-functional (COOH). The polyester resin may bethe reaction product of a polycarboxylic acid and a polyol. For the purposes of this invention, theterm polycarboxylic acid includes compounds having at least two carboxylic acid groups. For thepurposes of this invention, the term polyol includes compounds having at least two hydroxylgroups. For hydroxyl-functional polyester, the polyol is present relative to the polycarboxylic acidin an OH:COOH stoichiometric excess that ranges from 2:1 to 6:1. Excess polyol ensures that allfree carboxylic acid groups are consumed while allowing excess hydroxyl groups to remainunconsumed during the esterification reaction. The hydroxyl groups may be present at the terminalends of the polyester. For carboxyl-functional polyester, the polycarboxylic acid is present relativeto the polyol in a COOH:OH stoichiometric excess that ranges from 2:1 to 6:1. Excesspolycarboxylic acid ensures that all free hydroxyl groups are consumed while allowing excesscarboxylic acid groups to remain unconsumed during the esterification reaction. The carboxylicacid groups may be present at the terminal ends of the polyester.

[0056] The condensation reaction of hydroxyl-functional and carboxyl-functional compounds toform the polyester resin may be aided by a catalyst. In some non-limiting embodiments, thecatalyst may be selected from N-methylimidazole, diazabicyclo[2,2,2]octane,diazabicyclo[5,4,0]undec-7-ene and pentamethyldiethylenetriamine and mixtures thereof. Otherexamples of suitable esterification catalyst include tetrabutyl-o-titanate, stannous octoate, ptoluene sulphonic acid, and combinations thereof.

[0057] In non-limiting embodiments, the polyol may be a diol, a triol, or a higher-functional polyolhaving 4-8 hydroxyl groups (e.g. tetrol). In some embodiments, the polyol may be aromatic,cycloaliphatic, aliphatic, or a combination thereof. In some embodiments, the carboxyl-functionalcompound is dicarboxylic acid, a tricarboxylic acid, a higher functional polycarboxylic acid having4-8 carboxylic acid groups, or a combination thereof. In some embodiments, the polycarboxylicacid may be aliphatic, cycloaliphatic, aromatic, or a combination thereof.

[0058] Non-limiting examples of polyol may include a diol that is selected from alkylene glycols,such as ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, triethyleneglycol, tripropylene glycol, hexylene glycol, polyethylene glycol, polypropylene glycol andneopentyl glycol; hydrogenated bisphenol A; cyclohexanediol; propanediols including 1,2-propanediol, 1,3-propanediol, butyl ethyl propanediol, 2-methyl-1,3-propanediol, and 2-ethyl-2-butyl-1,3-propanediol; butanediols including 1,4-butanediol, 1,3-butanediol, and 2-ethyl-1,4-butanediol; pentanediols including trimethyl pentanediol and 2-methylpentanediol;cyclohexanedimethanol; hexanediols including 1,6-hexanediol; hydroxy-alkylated bisphenols;polyether glycols, for example, poly(oxytetramethylene) glycol. In some embodiments, the polyolmay be a triol or higher polyol that is selected from trimethylol propane, pentaerythritol, dipentaerythritol, trimethylol ethane, trimethylol butane, dimethylol cyclohexane, glycerol and thelike.

[0059] Non-limiting examples of polycarboxylic acid may include a dicarboxylic acid that isselected from adipic acid, azelaic acid, sebacic acid, succinic acid, glutaric acid, decanoic diacid,dodecanoic diacid, phthalic acid, isophthalic acid, 5-tert-butylisophthalic acid, tetrahydrophthalicacid, terephthalic acid, hexahydrophthalic acid, methylhexahydrophthalic acid, dimethylterephthalate, 2,5-furandicarboxylic acid, 2,3-furandicarboxylic acid, 2,4-furandicarboxylic acid,3,4-furandicarboxylic acid, 2,3,5-furantricarboxylic acid, 2,3,4,5-furantetracarboxylic acid,cyclohexane dicarboxylic acid, 1,3-cyclohexane dicarboxylic acid, 1,4-cyclohexane dicarboxylicacid, and anhydrides thereof, as well as mixtures thereof. In some embodiments, thepolycarboxylic acid may be selected from tricarboxylic acids such as trimellitic acid andanhydrides thereof.

[0060] Non-limiting examples of polyurethane resins for the powder coating composition aredisclosed, for example, in US Patent No. 4,404,320, and U.S. Patent No. 4,246,380. Suitablepolyester-urethane acrylates are disclosed, for example, in U.S. Patent No. 6,284,321. Suitableepoxy compounds for the powder coating composition are disclosed, for example, in U.S. Pat. No.5,732,052.

[0061] The specific type and amount of reactant used to create the polyester resin may influencethe melt viscosity, crystallinity, and Tg of the polymeric resin. Specifically, aromatic and / orcycloaliphatic monomers lead to high Tg polymers, and longer-chain aliphatic monomers lead tolower Tg polymers. For example, a polyester resin having a significant level of ester groups in thebackbone that are derived from terephthalic acid / isophthalic acid can have its Tg lowered byreplacing certain amounts of the terephthalic acid / isophthalic acid with adipic acid, therebymaking the polyester resins more flexible and more likely to flow at a lower temperature.However, substituting too much adipic acid will result in the polyester having a Tg that is too lowto be used in powder coating formulations.

[0062] In a non-limiting embodiment, the polymeric resin may have 100% solids content (i.e. isfree of solvent) and has a melt viscosity ranging from 2,000 mPa / s to 5,000 mPa / s at 200 °C -including all sub-ranges and integers there between. In the non-limiting embodiment, thepolymeric resin may have a Tg ranging from about 50 °C to about 70°C. In some embodiments,the polymeric resin may be hydroxyl-functional and have a hydroxyl value ranging from about 40to about 300. Non-limiting examples of suitable hydroxyl-functional polymeric resin includehydroxyl-functional polyester resin, such as commercially available Polymac 3110 and / or Rucote102. In some embodiments, the polymeric resin may be carboxyl-functional and have an acidnumber ranging from 30 to 50.

[0063] According to some embodiments of the present invention, the cross-linker comprises atleast one low molecular weight compound having at least two functional groups. The cross-linkermay comprise between 2 and 6 functional groups. In an alternative embodiment, the cross-linkermay comprise between 2 and 4 functional groups. The functional groups of the cross-linker maybe selected from hydroxyl groups, carboxylic acid groups, isocyanate groups, epoxy groups, anda combination thereof.

[0064] In some non-limiting embodiments, suitable cross-linkers may include the aforementionedpolyol compounds, polycarboxylic acid compounds, as well as polyisocyanate compounds andepoxy-functional compounds, such as glycidyl-functional acrylic copolymers. In someembodiments, the functional groups of the cross-linker may be temporarily blocked, as discussedherein, thereby enhancing the shelf-life of the precursor mixture during storage and shipment. Thespecific functional group will depend on the desired composition of the resulting powder coating.

[0065] The specific selection of cross-linker will depend on the type of polymeric resin and thedesired final matrix composition. For example, hydroxyl functional polyester may be cured withpolycarboxylic acid cross-linker, thereby resulting in a three-dimensional polyester matrix - withthe OH:COOH stoichiometric ratio of polyester resin to cross-linker being about 1:1 to ensure allfunctional groups on both the polymeric resin and cross-linker are consumed during theesterification cross-linking reaction.

[0066] The hydroxyl functional polyester may alternatively be cured with polyisocyanate crosslinker, thereby resulting in a polyester-polyurethane matrix. The OH:NCO ratio of polyester resinto polyisocyanate cross-linker being essentially 1:1 to ensure that all functional groups on both thepolymeric resin and cross-linker are consumed during the urethane forming cross-linking reaction.For the purposes of this invention, the term polyisocyanate refers to isocyanate-functionalcompounds having at least two isocyanate functional groups, such as diisocyanate, isocyanurate,biuret, isocyanurate allophanates. In a preferred embodiment, the polymeric resin is the polyesterpolyurethane resin.

[0067] The polyisocyanate of the present invention may be selected from compounds such asisophorone diisocyanate (IPDI), 4,4'-dicyclohexylmethane-diisocyanate, and trimethyl5 hexamethylene-diisocyanate, 1,6-hexamethylene diisocyanate, 2,2,4-trimethylhexamethylenediisocyanate, octadecylene diisocyanate and 1,4 cyclohexylene diisocyanate. toluene diisocyanate;methylenediphenyl diisocyanate; tetra methylxylene diisocyanate, and isocyanurates, biurets,allophanates thereof, as well as mixtures thereof, as well as adducts, isocyanurates, biurets, andallophanates thereof. In one embodiment, the polyisocyanate comprises IPDI.

[0068] According to some embodiments of the present invention, each of the free isocyanategroups present on the cross-linker may be temporarily blocked with a blocking agent to ensure nopremature reacting of the hydroxyl-groups and isocyanate groups occur before final curing -thereby extending the shelf-life of the precursor mixture during storage and shipment. Suitableblocking agents may include, for example, secondary or tertiary alcohols such as isopropanol ortert-butanol; C-H acidic compounds such as malonic dialkyl ester, acetylacetone, and acetoaceticalkyl ester, oximes such as formaldoxime, acetaldoxime, methyl ethyl ketone oxime,cyclohexanone oxime, acetophenone oxime, benzophenone oxime or diethylglyoxime, lactamssuch as ε-caprolactam, δ-valerolactam, γ-butyrolactam, phenols such as phenol, o-methylphenol;N-alkylamides such as N-methylacetamide, imides such as phthalimide, secondary amines such asdiisopropylamine, imidazole, pyrazole, and 1,2,4-triazole. In a preferred embodiment, the crosslinker is ε-caprolactam blocked IPDI.

[0069] The blocking agent may be employed relative to the free isocyanate groups in astoichiometric ratio of about 1:1 to ensure that all free isocyanate groups present on the crosslinker are temporarily blocked. The blocking agent prevents the isocyanate groups fromprematurely reacting with moisture or cross-linker at room temperature, but will deblock from theisocyanate group at an elevated temperature of at no more than 170 °C, thereby allowing the freeisocyanate groups to react with the cross-linker and form a fully cured matrix.

[0070] In other embodiments, the blocked polyisocyanate may be in the form of a uretdionemodified polyisocyanate. Uretdione modified polyisocyanates contain two free isocyanate groupsas well as two internally blocked isocyanate groups. The internal blocking of the isocyanate groupsoccurs without the need of an external blocking agent, such as ε-caprolactam. At elevatedtemperatures, the uretdione ring is broken and the two internally blocked isocyanate groups aremade available to react with isocyanate-reactive groups, such as hydroxyl groups, in a urethaneforming reaction. According to the present invention, the uretdione blocked polyisocyanate maybe formed from the above mentioned polyisocyanate compounds - such as IPDI. Afterdeblocking, uretdione based on diisocyanates will contain an equivalent of four isocyanate groups.

[0071] In some embodiments, a catalyst may be added to aid the urethane-forming reactionbetween the hydroxyl groups and the isocyanate groups. The catalyst may be selected fromorganometallic catalysts, such as dibutyltin dilaurate or tin octoate, or tertiary amines, such astriethylamine, pyridine, N,N-dimethylaminocyclohexane, or 1,4-diazabicyclo[2.2.2]octane. Othercatalysts may be selected from metal ion diacryliodium salts. The catalyst may be present in anamount ranging from about 0.001 wt. % to about 1 wt. % based on the total weight of the precursormixture. This range includes all specific values and sub-ranges there between, such as 0.002,0.005, 0.01, 0.02, 0.05, 0.1, 0.2, 0.5, and 0.8 wt. % based on the total weight of the precursormixture.

[0072] The polymeric resin may be an isocyanate terminated urethane-polyester prepolymer. Theprepolymer may be the reaction product of stoichiometric excess of polyisocyanate relative tohydroxyl-terminated polyester resin, the NCO:OH ratio ranging from 2:1 to 6:1. Excess isocyanateensures that all free hydroxyl groups are consumed during the formation of the polyurethaneprepolymer while ensuring that free isocyanate groups remain on the prepolymer. Any excess polyisocyanate remaining after the formation of the prepolymer may be stripped by low pressurevacuum. The free isocyanate groups present on the prepolymer may be blocked with previouslydiscussed isocyanate blocking agents in a stoichiometric ratio of blocking agent to the freeisocyanate of about 1:1 to ensure all free isocyanate groups present on the prepolymer aretemporarily blocked. The blocked isocyanate-terminated polyester prepolymer may then be mixedwith polyol cross-linker to form a storage stable precursor mixture. The polyol cross-linkercomprises the same low molecular weight polyol compounds listed with respect to the formationof the polyester resin.

[0073] In some embodiments, carboxyl functional polyester resin may be cured with polyol crosslinker, thereby resulting in a polyester matrix. The free carboxyl groups present on the carboxyl30 functional polyester resin may be present relative to the hydroxyl groups present on the crosslinker in a COOH:OH stoichiometric ratio of about 1:1, thereby ensuring that all functional groupspresent on both the polyester resin and the cross-linker are consumed during the esterificationcross-linking reaction. The polyol cross-linker comprises the same low molecular weight polyolcompounds listed with respect to the formation of the polyester resin.

[0074] The carboxyl functional polyester resin may also be cured with epoxy functionalcompounds. In some non-limiting embodiments, the epoxy functional compounds may includeepoxy resin that may be saturated or unsaturated, aliphatic, cycloaliphatic, aromatic orheterocyclic.

[0075] Examples of epoxy resins suitable for use in the invention include polyglycidyl ethers ofpolyhydric compounds, brominated epoxies, epoxy novolacs or similar polyhydroxyphenol resins,polyglycidyl ethers of glycols or polyglycols, and polyglycidyl esters of polycarboxylic acids.Preferably the epoxy resin is a polyglycidyl ether of a polyhydric phenol. Polyglycidyl ethers ofpolyhydric phenols can be produced, for example, by reacting an epihalohydrin with a polyhydricphenol in the presence of an alkali. Examples of suitable polyhydric phenols include: 2,2-bis(4-hydroxyphenyl) propane (bisphenol-A; 2,2-bis(4-hydroxy-tert-butylphenyl) propane; 1,1-bis(4-hydroxyphenyl) ethane; 1,1-bis(4-hydroxyphenyl) isobutane; 2,2-bis(4-hydroxytertiarybutylphenyl) propane; bis(2-hydroxynapthyl) methane; 1,5-dihydroxynaphthalene; 1,1-bis(4-hydroxy-3-alkylphenyl) ethane and the like.

[0076] The binder composition may be substantially free of a volatile solvent, excluding moisturecontent. For the purposes of this invention, the term "substantially free" means less than 0.1 wt.20 % based on the total weight of the referenced element. In a non-limiting example, a mixturecomprising binder, cross-linker, and filler that is substantially free of solvent comprises solvent inan amount less than 0.05 wt. % based on the total weight of the mixture - preferably less than 0.01wt. %. According to a preferred embodiment, the binder composition of the present invention has100% solids is free of solvent - include volatile organic solvents. Furthermore, according toadditional embodiments of the present invention, the binder composition is substantially free ofpolymer resin comprising fluoro-carbon groups, such as fluoro-modified polyurethane andfluoropolymer, e.g., PVDF, or PTFE. Stated otherwise, the polymeric resin, which makes up thebinder composition of the present invention, is substantially free of fluoro-carbon groups.

[0077] The powder coating may further comprise additives, fillers, coating performanceenhancers. Such fillers and additives may include, but are not limited to, inert fillers, antioxidants,stabilizers, pigments, reinforcing agents, reinforcing polymer, lubricants, antimicrobial additive(e.g., fungicides), degassers, a surfactant, flow additives, dispersants, thixotropic agents, adhesionpromoters, light stabilizers, flame retardants, anticorrosion agents, inhibitors, leveling agents, anticratering agents, and mixtures thereof. In some embodiments, the fungicide may be present in anamount ranging from about 6 wt. % to about 10 wt. % based on the total weight of the powdercoating composition. In a non-limiting example, the fungicide may comprise zinc borate, 2-(-4-thiazolyl) benzimidazole.

[0078] According to the present invention, the powder coatings comprising an antimicrobialadditive may be referred to as an antimicrobial coating or antimicrobial powder coating. The term"antimicrobial". refers to coatings that exhibit resistance to fungi (e.g., mildew, mold) and / orbacterial growth. The antimicrobial coating of the present invention may be the powder coatingwith or, optionally, without the anti-soiling surfactant.

[0079] The antimicrobial coating may be applied directly to one of the surfaces of the substrate.Specifically, the antimicrobial coating may be in contact and bonded to the exposed surface of thesubstrate. In other embodiments, there may be one or more intervening coatings or layers betweenthe substrate surface and the antimicrobial coating.

[0080] The antimicrobial coating may be present on one or more surfaces of the substrate in acoating thickness that ranges from about 40 μm to about 120 μm - including all thickness and subranges there-between. The antimicrobial coating may be present on one or more surfaces of thesubstrate in a coating thickness that ranges from about 130 g / m2to about 340 g / m2- including allamounts and sub-ranges there-between.

[0081] The antimicrobial coating may comprise an antimicrobial additive dispersed throughout across-linked polymer. The antimicrobial coating may further comprise one or more pigments. Theantimicrobial coating may further comprise one or more other additives and / or fillers. The crosslinked polymer may be formed from a powder coating precursor (also referred to as "precursor").The precursor may comprise a high-solids mixture of a polymeric resin and cross-linker - asdiscussed further herein. The cross-linked polymer forms a three-dimensional polymer matrix inwhich the antimicrobial additive, pigment, fillers, and / or other additives are dispersed throughout- as discussed further herein.

[0082] The antimicrobial additive of the present invention includes a blend of a first componentand a second component. The first component generally comprises a metal borate and the secondcomponent comprises a benzimidazole compound.

[0083] According to the present invention, the metal borate of the first component refers to acompound corresponding to basic, dibasic, tribasic and polybasic metal borate(s), and mixturesthereof. For example, "zinc borate" refers to a group of compounds consistingzinc borate (ZnB4O7), any of the corresponding basic zinc borates (such as monobasiczinc borate of the structure Zn(OH).B4O7, dibasic basic zinc borate of the structure2Zn(OH)2.B4O7, tribasic zinc borate of the structure 3Zn(OH)3.B4O7 and the like), and mixturesthereof. As another example, "copper borate" refers to a group of compounds selected from thegroup consisting copper borate (CuB4O7), any of its the corresponding basic copper borates (suchas monobasic copper borate of the structure Cu(OH).B4O7, dibasic basic copper borate of thestructure 2Cu(OH)2.B4O7, tribasic copper borate of the structure 3Cu(OH)3.B4O7, and the like),and mixtures thereof. The metal borate may include more than one metal. In a preferredembodiment, the metal borate is zinc borate.

[0084] The benzimidazole compound of the second component refers to a compound having the astructure of Formula I:Formula I

[0085] Wherein R1, R3, R4, R5, and R6 may be selected from H, a halogen atom (e.g., Br, I, Cl),and C1-C6 chain. R2 may be selected from a sulfur-containing heterocyclic compound - such asthiazolyl group. The benzimidazole compound may have an R2group that is a 4-thiazolyl group.The benzimidazole compound may have R1, R3, R4, R5, and R6groups that are hydrogen atoms.In a preferred embodiment, the benzimidazole compound is 2-(4-Thiazolyl)benzimidazole havingthe structure of Formula II:Formula II

[0086] In some embodiments, the benzimidazole compound of the present invention may besubstantially free of carbonyl groups.

[0087] The first component and the second component may be present in the antimicrobialadditive resulting in a weight ratio between the first component (metal borate) and the secondcomponent (benzimidazole compound) that ranges from about 75:1 to about 10:1 - including allratios and sub-ranges there-between. In some embodiments, the first component and the secondcomponent may be present in a weight ratio ranging from about 70:1 to about 30:1 - including allratios and sub-ranges there-between. In a preferred embodiment, the first component and thesecond component may be present in a weight ratio ranging from about 70:1 to about 40:1-including all ratios and sub-ranges there-between. The first component and the second componentmay be present in a weight ratio of about 70:1.

[0088] The antimicrobial additive of the present invention may be substantially free of compoundscomprising carbamate groups. In some embodiments, the antimicrobial additive of the presentinvention may be substantially free of compounds comprising halogen atoms.

[0089] It has been surprisingly discovered that the combination of the metal borate - specificallythe zinc borate - and the sulfur-containing benzimidazole compound provides a synergisticimprovement in antimicrobial activity to the resulting coating. Specifically, the combination ofmetal borate and sulfur-containing benzimidazole provides more than adequate antimicrobialproperties to the resulting coating at reduced amounts of the antimicrobial additive in the overallcoating. Specifically, the antimicrobial additive may be present in the overall antimicrobialcoating in an amount ranging up to about 10 wt. % based on the total weight of the antimicrobialcoating. In a preferred embodiment, the antimicrobial additive may be present in the overallantimicrobial coating in an amount ranging from about 6 wt. % to about 10 wt. % - including allamounts and sub-ranges there-between - based on the total weight of the antimicrobial coating.With less antimicrobial additive be required in the overall coating, the resulting antimicrobialcoating can be manufactured at a lower cost.

[0090] The antimicrobial additive may also be present in amounts represented by parts by weight,whereby the antimicrobial additive is present in an amount ranging from about 6 to about 10 partsby weight based on 100 parts by weight of the overall antimicrobial coating composition -including all parts by weight and sub-ranges there-between.

[0091] The precursor composition may further comprise reinforcing polymer, such as acryliccopolymers that further comprise functional groups capable of reacting with the functional groupspresent in the binder. In a non-limiting example, the reinforcing polymer may comprise glycidyl10 functional acrylic polymer. As previously discussed, glycidyl groups are capable of reacting withcarboxylic acid groups.

[0092] Yet further additives include metals and metal oxides such as, for instance, chromiumoxide, chromium, zinc oxide, copper oxide, copper, nickel, titanium, stainless steel, aluminum,titanium dioxide, tin oxide, iron, iron oxide, and the like. Such metals may serve, for instance, as abrasion-resistant fillers, compatibilizers, or as pigments. Pigments may further includecompounds such as titanium dioxide, barium sulfate, calcium carbonate, or a combination thereof.In some embodiments of the present invention, the pigments may have an average particle sizeranging from 180 nm to 220 nm; in a preferred embodiment, the pigment has an average particlesize of about 200 nm. In some embodiments, the powder coating according to the present inventionmay comprise about 15 wt. % to about 30 wt. % of pigment. According to some embodiments,the powder coating according to the present invention may comprise about 20 wt. % of titaniumdioxide.

[0093] In some embodiments of the present invention, the pigments may have an average particlesize ranging from about 0.2 microns (μm) to about 5 μm - including all sizes and sub-ranges there25 between. The antimicrobial coating may comprise pigment in an amount ranging from about 20wt. % to about 50 wt. % - including all amounts and sub-ranges there-between - based on the totalweight of the antimicrobial coating. In some embodiments, the pigment may be pretreated withthe antimicrobial additive before being blended with the precursor and / or other additives andfillers.

[0094] Another benefit of the unexpected synergy between the metal borate and sulfur-containingbenzimidazole compound is that the antimicrobial composition and precursor (as well as otheradditives and fillers) may be applied to a substrate at a solids content of about 100% - i.e.,substantially free of solvent. Without needing solvent to apply the antimicrobial coating, theantimicrobial coating may be suitable as a powder coating.

[0095] The powder coating of the present invention may comprise a surfactant. The surfactantaccording to the present invention may be added to the precursor mixture in a surfactantcomposition prior to final processing and curing, as discussed herein. The fluorosurfactant maybe non-ionic or ionic. Non-limiting examples of ionic fluorosurfactant include cationicfluorosurfactant and anionic fluorosurfactant. In a preferred embodiment, the fluorosurfactant ofthe powder coating may be anionic.

[0096] The surfactant composition according to the present invention is substantially free ofsolvent or liquid carrier - preferably having a solid's content of 100% and substantially free ofsolvent or liquid carrier, including volatile organic solvents and / or water. The surfactantcomposition is in powder form at room temperature. The surfactant composition comprises atleast one fluorosurfactant. In other embodiments, the surfactant composition according to thepresent invention may be a liquid-based surfactant comprising an anionic fluorosurfactant mixedwith a liquid carrier - as discussed in greater detail herein.

[0097] The anionic fluorosurfactant may have a melting temperature that ranges from about 50 °Cto about 70 °C. The anionic fluorosurfactant of the present invention has a low pH value - rangingfrom about 1 to about 6, including all value and sub-ranges there between. The anionic moiety ofthe anionic fluorosurfactant may be selected from a sulfate, sulfonate, phosphate, or carboxylatemoiety, wherein preferred is a phosphate moiety. Non-limiting examples of the anionicfluorosurfactant includes at least one of the following formulas:Formula I: (Rf1AO)P(O)(O-M+)2Formula II: (Rf1AO)2P(O)(O-M+)

[0098] wherein Rfis a C1 to C16 linear or branched perfluoroalkyl, which may be optionallyinterrupted by one, two or three ether oxygen atoms.

[0099] A is selected from: (CH2CF2)m(CH2)n; (CH2)oSO2N(CH3)(CH2)p; O(CF2)q(CH2)r; orOCHFCF2OE;

[0100] m is 0 to 4;

[0101] n, o, p, and r, are each independently 2 to 20;

[0102] q is 2;

[0103] E is a C2 to C20 linear or branched alkyl group optionally interrupted by oxygen, sulfur, ornitrogen atoms; a cyclic alkyl group, or a C6 to C10 aryl group;

[0104] M is a Group I metal or an ammonium cation (NHx(R2)y)+, wherein R2 is a C1 to C4 alkyl;x is 1 to 4; y is 0 to 3; and x + y is 4.

[0105] In a preferred embodiment, the fluorosurfactant may consist of the anionic fluorosurfactantof formula III:Formula III: (Rf2CH2CH2O)P(O)(ONH4)2

[0106] wherein Rf2 is a C4 to C8 perfluoroalkyl group having the formula: F[CF2-CF2]3-8. Inpreferred embodiments, the fluorosurfactant is a solvent-free anionic fluorosurfactant. Suitableanionic fluorosurfactants are commercially available.

[0107] According to some embodiments, the fluorosurfactant may be present in an amount rangingfrom about 0.05 wt. % to about 4 wt. % based on the total weight of the powder coating. In apreferred embodiment, the fluorosurfactant may be present in an amount ranging from about 0.7wt. % to 3 wt. % based on the total weight of the powder coating. In some embodiments, thefluorosurfactant may be present in an amount ranging from about 1.5 wt. % to 3 wt. %,alternatively from about 0.1 wt. % to 0.3 wt. % based on the total weight of the powder coating.According to some embodiments, the fluorosurfactant may be present in an amount ranging from10 wt. % to 25 wt. % based on the total weight of a pigment - including all sub-ranges and integersthere between.

[0108] The pigment, e.g., titanium dioxide, may be pretreated with the surfactant compositionprior to be added to the precursor mixture. In a preferred embodiment, the pigment is pretreatedwith anionic fluorosurfactant according to the following steps: heating the anionic fluorosurfactantcomposition of the present invention to an elevated temperature to melt the anionicfluorosurfactant, which may range from 50 °C to 70 °C (including all integers and sub-rangesthere-between), followed by the addition of the titanium oxide. The anionic fluorosurfactant andthe pigment are then mixed, thereby creating the pretreated titanium dioxide pigment. In someembodiments, the elevated temperature may be 55 °C. The pretreated pigment can be cooled toroom temperature and later mixed with the binder and cross-linker to form the precursor mixture,as discussed herein. In a preferred embodiment, the pigment is titanium dioxide that is pretreatedwith the anionic fluorosurfactant of formula III. It has been found that pretreating the pigmentwith the fluorosurfactant before the other ingredients of the coating compositions are added toproduce the coating composition mixture ensures uniform dispersion of the fluorosurfactant in thecoating composition.

[0109] The first coating 130 may be formed by first mixing together the binder, cross-linker, andadditives (including the anti-microbial additive in the case of antimicrobial coatings), and fillersto form a precursor mixture. The precursor mixture may be lightly mixed at room temperature bya dry blender for a period of time, thereby creating an evenly distribution of binder, cross-linker,and additives / fillers in the precursor mixture. After dry blending, the precursor mixture may bemelt-mixed and pelletized according to the discussion herein.

[0110] The precursor mixture may then be processed in a melt extruder. The melt extruder maybe a single screw or twin-screw extruder. The melt extruder may comprise three zones: (1) a feedzone; (2) a melt zone; and (3) dispersion zone. The feed zone may be held at a temperature that isless than or equal to room temperature to prevent blockages of the precursor mixture. The meltzone is generally heated above the maximum Tg of the precursor mixture but below the deblocking and reaction temperature of the precursor mixture. Operating between above the Tg andbelow the de-blocking / reaction temperature allows the precursor mixture to become molten andflow without the precursor mixture prematurely deblocking and reacting inside of the extruder. Inthe dispersion zone, the temperature is maintained above the Tg and below the deblockingtemperature, thereby allowing the precursor mixture to become a uniform. In some embodiments,the melt zone and dispersion zone are operated at a temperature ranging from about 90 °C to 15020 °C - including all sub-ranges and integers there-between. In some embodiments, the melt zoneand dispersion zone are operated at a temperature ranging from about 90 °C to about 130 °C -including all sub-ranges and integers there-between. In some embodiments, the melt zone anddispersion zone are operated at a temperature ranging from 100 °C to 110 °C. The extruder willcomprise a heating means and a cooling means to ensure that the various zones stay within theappropriate temperature ranges.

[0111] After passing through the dispersion zone, the melt-mixed precursor mixture passedthrough an extruder exit die. The exit die may be provided with a plurality of apertures in manydifferent configurations. In some embodiments, the exit die may be replaced by other deviceswhich allow for a pressure drop across them; for example, such a pressure drop could be achievedusing a particular screw configuration. In any event, the average residence time of the precursormixture in the melt extruder will generally be less than 5 minutes and more typically in the rangefrom 30 to 120 seconds. As the molten precursor mixture passes through the die, it is cooled, andpelletized. The pellets are ground and the resulting precursor powder is then collected. In somenon-limiting embodiments, the precursor mixture may be ground by machine, such as a grinder,cryogenically grinder, or the like. The resulting precursor powder may have an average particlesize of less than 100 μm, typically ranging from 30 to 50 μm.

[0112] According to an alternative embodiment of the present invention, the first coating 130 maybe produced according to an alternative process. The alternative process includes a liquid-basedsurfactant. Previously, liquid-based surfactants were not used to in the creation of powdercoatings. The liquid based surfactant may comprise a liquid carrier that is pre-mixed with at leastone of the previously discussed fluorosurfactants. In a preferred embodiment, the liquid basedsurfactant comprises a liquid carrier that is pre-mixed with at least one of the previously discussedanionic fluorosurfactants. Non-limiting examples of liquid carrier include water as well as otherliquids that are not flammable below 120 °C and / or do not emit toxic vapors below 120 °C.

[0113] The liquid-based surfactant may comprise liquid carrier in an amount ranging from about10 wt. % to about 75 wt. % based on the total weight of the liquid carrier and the surfactant in thedry-state - including all amounts and sub-ranges there-between. In a preferred embodiment, theliquid-based surfactant may comprise the liquid carrier in an amount ranging from about 30 wt. %to about 75 wt. % based on the total weight of the liquid carrier and the surfactant in the dry-state- including all amounts and sub-ranges there-between.

[0114] The liquid-based surfactant may be blended together with the binder, cross-linker, andadditives and / or fillers to form a wet-precursor mixture. The liquid-based surfactant may bepresent in the wet-precursor mixture in an amount ranging from about 0.05 wt. % to about 4 wt.% based on the total weight of the wet-precursor mixture - including all amounts and sub-rangesthere-between.

[0115] Alternatively, to ensure proper distribution of each component within the wet-precursormixture, the blend of liquid-based surfactant may be blended together with the binder, cross-linker,and additives and / or fillers may be mixed together for a number of blending cycles that includes ablending period and a cooling period.

[0116] In a non-limiting embodiment, each blending period of a blending cycle may span a firsttime period ranging from about 5 seconds to about 30 seconds - including all times and sub-rangesthere-between. In a non-limiting embodiment, each cooling period of a blending cycle may spana second time period ranging from about 5 seconds to about 120 seconds - including all times andsub-ranges there-between. A ratio between the first time period and the second time period for asingle blend cycle may range from about 1:1 to about 1:20 - including all ratios and sub-rangesthere-between.

[0117] In a preferred embodiment, the second time period is greater than the first time period foreach blend cycle. In a preferred embodiment, the blend cycle may be less than about 10 secondsto avoid excess heat build-up. A total number of blending cycles may range from about 1 to about- including all number of blend cycles and sub-ranges there-between.

[0118] The length of each blending cycle and the total number of blending cycles are selected suchthat the wet-precursor mixture is fully blended without any clumping or any portion of the wetprecursor mixture melting due to heat build-up. Non-limiting examples of suitable blendersinclude a blend with side scrappers having high heat conduction. In some embodiments, theblender may be a cooled blender that helps regulate the temperature of the wet precursor mixtureduring blending. The blend cycles and / or blending equipment may be operated such that the wet15 precursor never exceeds a temperature of 120 °F during blending. In other embodiments, the blendcycles and / or blending equipment may be operated such that the wet-precursor never exceeds atemperature of 80 °F during blending. During blending, the liquid carrier may become absorbedby one or more components of the precursor mixture (e.g., the pigments), and, therefore the wetprecursor mixture will still comprise the liquid carrier as it may not evaporate off during blending.

[0119] By blending the precursor mixture in a wet-state and below the melting temperature of anycomponent within the pre-cursor mixture is that the waxy anionic surfactant is better distributedthroughout the precursor mixture - thereby providing greater uniformity of anti-soilingperformance in the final coating - even at relatively low amounts of the anionic surfactant. Onceblended, the wet-precursor may be dried and pelletized according to the previously discussedmethodology. During extrusion, the liquid-carrier may be evaporated off resulting in the precursorhaving a substantially 100% solids content. In a non-limiting example, the wet-precursor may beextruded at a temperature above 100 °C - preferably between 105 °C and 110 °C - to ensure thatthe liquid carrier is evaporated from the wet-precursor mixture.

[0120] A predetermined amount of the precursor powder may then be placed in a container, whichis either placed into storage or shipped to another location for final processing, as discussed herein.In other embodiments, the precursor powder may finally be processed at the same site as the melt-mixing. Final processing includes spray coating or electrostatic coating the precursor powder ontoa substrate 120. The spray coating may be applied by a spray gun in an electrostatic field or witha triboelectric gun in which the powder is charged by friction.

[0121] After the precursor powder is spray coated onto the substrate 120, the resulting spraycoating is cured by heating in an oven at a curing temperature that is above the deblocking andreaction temperature of the precursor mixture. The curing temperature may range from about 160°C to 210 °C. Curing may occur for a period of time sufficient for the binder and cross-linker tofully react, thereby forming the fully cured powder coating that is the first coating 130. The curingmay occur for a period of time ranging from 15 to 30 minutes for temperature ranging from about160 °C to 190 °C. In other embodiments, the curing may occur for a period of time ranging fromabout 6 to 15 minutes for temperatures ranging from about 190 °C to 210 °C. The resulting powdercoating has a thickness ranging from 40 μm to 120 μm - including all sub-ranges and thicknessesthere-between.

[0122] The resulting substrate coated with the antimicrobial coating is suitable as an antimicrobialarticle, such as a building panel for installation in interior room environments, whereby thebuilding panel not only exhibits superior resistance to bacterial, mold, and fungal growth, butexcels as reducing the amount of pre-existing viable microbial.

[0123] After providing the substrate 120 coated with the first coating 130 applied thereto, theupper surface of the first coating 130 may be coated with the second coating 140. The secondcoating 140 may be formed by applying a liquid-based coating composition to the upper surface131 of the first coating 130 and then drying the liquid-based coating composition to form thesecond coating 140 atop the first coating 130. The liquid-based coating composition may beprepared by mixing together a liquid carrier with a repellant component. The repellant componentmay be a fluoro-containing repellent component. The fluoro-containing repellent component maybe selected from fluoropolymer, the aforementioned fluorosurfactants, or a combination thereof.In a preferred embodiment, the fluoro-containing repellent component is an ionic fluorosurfactant.

[0124] The liquid carrier may be selected from water, VOC solvent, and combinations thereof. Ina preferred embodiment, the liquid carrier is water. The fluoropolymer may be selected fromfluorinated acrylic copolymer, fluorinated acrylic alkylamino copolymer, and combinationsthereof. The molecular weight of the fluoropolymer may range from about 1,000 Mn to about10,000,000 Mn - including all weights and sub-ranges there-between.

[0125] Non-limiting examples of fluorinated acrylic polymer include polymer produced bypolymerizing acrylate-functional monomer containing fluoride atoms and, optionally, at least oneother acrylate-functional monomer that is free of fluoride atoms. Non-limiting examples acrylatefunctional monomer containing a fluoride (also referred to "fluoro-acrylate") atom includevinylidene fluoride, vinylfluoride, chlorotrifluoroethylene, hexafluoropropene,tetrafluoroethylene, perfluoromethylvinylether, trifluoroethylene and mixtures thereof. Nonlimiting examples of acrylate-functional monomer that is free of fluoride atoms include acrylicacid, methacrylic acid, as well as acrylate and / or methacrylate esters.

[0126] The fluoropolymer of the present invention may be ionic. The fluoropolymer of the presentinvention may have an acidic pH that ranges from about 3 to about 6 - including all pHs and subranges there-between. The fluoropolymer of the present invention may have a basic pH that rangesfrom about 9 to about 11 - including all pHs and sub-ranges there-between. In some embodiments,the fluoropolymer may be anionic and have a pH that ranges from about 9 to about 11 - includingall pHs and sub-ranges there-between. In some embodiments, the fluoropolymer may be cationic and have a pH that ranges from about 3 to about 6 - including all pHs and sub-ranges therebetween. As discussed further herein, it has surprisingly been discovered that non-ionicfluoropolymer does not provide dirt and oil repellency as well as the ionic fluoropolymers providedherein.

[0127] In a non-limiting example, a cationic fluoropolymer may be produced by copolymerizinga fluoro-acrylate with a monomer capable of forming a salt, whereby the covalently bonded groupformed from the monomer has a positive charge - e.g., such as N-dimethylaminoethylmethacrylate acid, whereby the amino group is reacted with diethyl sulphate to form a cationicgroup pendant from the fluoropolymer.

[0128] In a non-limiting example, a cationic fluoropolymer may be produced by copolymerizinga fluoro-acrylate with a monomer capable of forming a salt, whereby the covalently bonded groupformed from that monomer has a negative charge - e.g., such as methacrylic acid, whereby thecarboxylic acid group is reacted with ammonia to form an anionic group pendant from thefluoropolymer.

[0129] The liquid carrier may be present in an amount ranging from about 80 wt. % to about 99.98wt. % - based on the total weight of the liquid-based coating composition - including allpercentages and sub-ranges there-between. The fluoropolymer may be present in an amountranging from about 0.02 wt. % to about 20 wt. % based on the total weight of the liquid-basedcoating composition - including all percentages and sub-ranges there-between.

[0130] The liquid-based coating composition may be applied to the upper surface 131 of the firstcoating 130 by spray coating, roll coating, dip coating, or wiping. The liquid-based coatingcomposition may be applied to the upper surface 131 of the first coating 130 in an amount rangingfrom about 80 g / m2to about 200 g / m2- including all sub-ranges and amounts there-between. In apreferred embodiment, the liquid-based coating composition may be applied to the upper surface131 of the first coating 130 in an amount ranging from about 105 g / m2to about 122 g / m2-including all sub-ranges and amounts there-between. After application, the liquid-based coatingcomposition covers both the upper surface 131 of the first coating 130 as well as penetrates and atleast partially fills the voids created by the surface imperfections 135 on the first coating 130.

[0131] After application, the liquid-based coating composition is dried for a period of time rangingfrom about 5 min to about 60 min and at a temperature ranging from about 15 °C to about 40 °C- thereby driving off the liquid carrier and transforming the liquid-based coating composition intothe second coating 140. According to the present invention, the term "drying" or "dried" refers todriving liquid carrier from a referred to composition. The term "drying" or "dried" does not referto chemically reacting a composition with a secondary composition - e.g., chemically curingpolymeric binder resin with cross-linking agent. Thus, the second coating 140 comprising thefluoropolymer may be applied to the first coating 130 without the need of additional high20 temperature curing (such as used in the curing stage of the first coating 130).

[0132] After drying, the resulting second coating 140 may substantially free of all liquid-carrier.The resulting building panel 100 comprises fluoropolymer applied to the upper surface 131 of thefirst coating 130 in a dry-state in an amount ranging from about 0.02 g / m2to about 2 g / m2-including all sub-ranges and amounts there-between - wherein the fluoropolymer forms a topcoatfor the building panel 100.

[0133] After drying the building panel 100, fluoropolymer remains applied to not only the uppersurface 131 of the first coating 130 but also within the surface defects 135 of the first coating 130.Specifically, the second coating 140 comprises filling portions 145 that cause at least a portion ofthe fluoropolymer of the second coating 140 to be present within the surface defect 135 of the firstcoating 130 such that at least a portion of the fluoropolymer of the second coating 140 is locatedbetween the upper surface 131 and the lower surface 132 of the first coating 130.

[0134] The application of the second coating 140 comprising the fluoropolymer to the first coating130 imparts added resistance to dirt pick-up resistance (e.g., finger print oils and sweat), whichresults in a building panel 100 that can withstand cosmetic damage that would otherwise typicallyoccur during installation. The added resistance to dirt pick-up may be measured as a function ofchange in color value - i.e. "Delta E" (Δ E).

[0135] Delta E value is measured by the following calculation:ΔE = [(L2-L1)2 + (a2-a1)2 + (b2-b1)2]1 / 2

[0136] wherein L1, a1, and b1 are each initial color values of an unsoiled first major surface 111 ofa building panel 100 that are measured using a Minolta Chroma Meter CR 410 from MinoltaCorporation. The L2, a2, and b2 values are the color values as measured by the Minolta ChromaMeter CR 410 after each first major surface 111 of the building panel 100 has been soiled by a dirtcomposition (i.e., finger oils, sweat, etc.). A smaller ΔE value indicates improved resistance todirt pick-up. According to the present invention, the combination of the first coating 130 and thesecond coating 140 can provide a building panel having a ΔE value less than 2.

[0137] Additionally, the combination of the first coating 130 and the second coating 140 mayresult in the first major surface 111 of the building panel having enhanced hydrophobicity.According to the present invention, the term "hydrophobicity" or "hydrophobic" means acomposition that is extremely difficult to wet and is capable of repelling liquid water underatmospheric conditions. Thus, as used herein, the term "hydrophobic" refers to a surface thatgenerates a contact angle of greater than 90° with a reference liquid (i.e. water).

[0138] The notion of using the contact angle made by a droplet of liquid on a surface of a solidsubstrate as a quantitative measure of the wetting ability of the particular solid has also long beenwell understood. Wetting is the ability of a liquid to maintain contact with a solid surface, resultingfrom intermolecular interactions when the two are brought together. The degree of wetting(wettability) is determined by a force balance between adhesive and cohesive forces. If the contactangle is greater than 90° for the water droplet to the substrate surface then it is usually consideredto be hydrophobic.

[0139] The first major surface 111 of the building panel 100 according to the present inventionexhibits a water contact angle of at least about 115°. In a preferred embodiment, the first majorsurface 111 of the building panel 100 exhibits a water contact angle ranging from about 125° toabout 135° - including all sub-ranges and angles there-between. At this contact angle, mostcommon waters and oils (e.g., fingerprint oils) will not wet the first major surface 111 of thebuilding panel 100 - thereby making the building panel 100 resistant to smudging duringinstallation.

[0140] Referring now to Figures 5 and 6, an alternative embodiment of the present inventionincludes a ceiling system 10 in an interior space, whereby the interior space comprises a plenumspace 3 and an active room environment 2. The ceiling system 10 may comprise a support grid 30whereby the plenum space 3 is located above the support grid 30 and below a roof or subfloor 4of an above adjacent floor in the building. The plenum space 3 provides space for mechanicallines within a building (e.g., HVAC, plumbing, etc.). The active space 2 provides room for thebuilding occupants during normal intended use of the building (e.g., in an office building, theactive space would be occupied by offices containing computers, lamps, etc.).

[0141] The support grid 30 may comprise a plurality of first support struts 32 and a plurality ofsecond support struts 33. Each of the first support struts 32 may be parallel to each other. Eachof the second support struts 33 may be parallel to each other. The plurality of first support struts32 may be orthogonal or perpendicular to the plurality of second support struts 33, thereby formingan intersecting pattern of struts that form the support grid 30. The support grid 30 may compriseopenings 31 formed by the intersecting first and second support struts 32, 33 which can receive abuilding panel 20, thereby forming the ceiling system 10.

[0142] At least one of the first support struts 32 and the second support struts 33 may comprise aninverted T-bar having a horizontal flange 41 and a vertical web 42. The horizontal flange 41 maycomprise a lower surface 41a and an upper surface 41b - wherein the lower surface 41a faces theactive room environment 2 and the upper surface 41b faces the plenum space 3 in the installedstate. The lower surface 41a faces opposite the direction in which the vertical web 42 extendsfrom the horizontal flange 41.

[0143] According to this embodiment, the first coating 130 of the present invention may be applieddirectly to the lower surface 41a of the horizontal flange 41 of at least one of the first and / or secondsupport struts 33 as previously discussed. The second coating 140 may then be applied to the firstcoating 130, as previously discussed. The present invention may further provide for a ceilingsystem 10 comprising a coated support grid 60 comprising the support grid 30, the first coating130, and the second coating 140 - whereby the first coating 130 is applied to at least a portion ofthe upper surface 41a of horizontal flange 41 of the support grid 30 and the second coating 140applied to the first coating 130 and whereby the upper surface 141 of the second coating 140 facesthe active room environment 2.

[0144] According to the present invention, the anti-soiling articles of the present invention maybe the result of one of many configurations. According to some embodiments, the article maycomprise a substrate 120 coated with the first coating 130, whereby the first coating 130 comprisesthe liquid-based anionic fluorosurfactant. In such embodiments, the second coating 140 mayoptionally be present. In such embodiments, the upper surface of the first coating 130 may forma major surface of the article. In such embodiments, the second coating 140 may optionally bepresent, whereby the second coating 140 comprises a fluoro-containing repellent component thatincludes fluoropolymer, fluorosurfactant, or a combination thereof.

[0145] According to other embodiments, the anti-soiling article may comprise a substrate 120coated with the first coating 130, whereby the first coating 130 comprises the waxy (i.e. solid)anionic fluorosurfactant. In such embodiments, the second coating 140 may optionally be present.In such embodiments, the upper surface of the first coating 130 may form a major surface of thearticle. In such embodiments, the second coating 140 may optionally be present, whereby thesecond coating 140 comprises a fluoro-containing repellent component that includesfluoropolymer, fluorosurfactant, or a combination thereof.

[0146] According to other embodiments, the anti-soiling article may comprise a substrate 120coated with the first coating 130, whereby the first coating 130 does not comprise a fluoro20 containing repellent component. In such embodiments, the article further comprises the secondcoating 140, whereby the second coating comprises a fluoro-containing repellent component thatincludes fluoropolymer, fluorosurfactant, or a combination thereof. In such embodiments, thesecond coating 140 forms a major surface of the article. In such embodiments, the second coating

[0147] The following examples are prepared in accordance with the present invention. Thepresent invention is not limited to the examples described herein.EXAMPLESAnti-Soiling Test Protocol of Topcoat

[0148] The following experiment measures the oil and dirt repellency on the major surface of thebuilding panel according to the present invention. Building panels were prepared having apolymeric powder coating that is formed from a powder coating precursor is prepared by mixingprecursor components together (i.e., a polymeric binder, cross-linker, and fluorosurfactant). Thefluorosurfactant has 100% solids and includes an anionic fluorosurfactant having at least onephosphate group. The anionic fluorosurfactant has a melting temperature between 50 °C and 70°C and a pH value between 1 and 5. An exemplary suitable anionic fluorosurfactant iscommercially available from Du Pont, under the tradename Capstone FS-66.

[0149] The powder coating precursor is then melt-mixed by extruder at a temperature rangingfrom about 90°C to about 110 °C, followed by pelletizing the resulting extrudate into a powder.Each resulting powder is spray coated onto a first major surface of an aluminum substrate. Thecoated substrate is then heat cured at a temperature of 195 °C to form the powder coated substrate.

[0150] Example 1

[0151] A liquid-based coating is then applied to the top surface of the powder coating, whereinthe liquid-based coating comprises 80 wt. % water and 20 wt. % of a first repellent component.The first repellent component being a cationic fluorosurfactant having a pH ranging from about 4to about 6 and a density of 1.06 g / cm3. The liquid-based coating is applied in an amount of 10g / m2 onto the powder coating. The resulting liquid-based coating was then dried at a temperaturebetween 15 °C and 40 °C to form the building panel of Example 1. The resulting building panelof Example 1 has fluorosurfactant applied atop the powder coating in an amount of about 2 g / m2.

[0152] Example 2

[0153] A second building panel (Example 2) was prepared according to the same methodology ofExample 1, except that the liquid-based coating composition was diluted to a concentration of 0.2wt. % of a second repellent component. The second repellent component being an anionicfluorosurfactant having a pH ranging from about 9 to about 11 and a density of about 1.1 g / cm3.The liquid-based coating composition was then applied to the fluorosurfactant containing powdercoating at a rate of 10 g / m2, and the liquid-based coating composition was dried. The resultingbuilding panel of Example 2 has fluorosurfactant applied atop the powder coating in an amount ofabout 0.02 g / m2.

[0154] Comparative Example 1

[0155] A third building panel (Comparative Example 1) was prepared according to the samemethodology of Example 2, except that a first non-ionic fluorosurfactant is used in place of thesecond repellent component. The non-ionic fluorosurfactant has a pH ranging from about 7 toabout 8.5 and a density of about 1.4 g / cm3- commercially available as FS-3100 from DuPont.The resulting building panel of Comparative Example 1 has 0.02 g / m2of fluorosurfactant appliedatop the powder coating.

[0156] Comparative Example 2

[0157] A fourth building panel (Comparative Example 2) was prepared according to the samemethodology of Example 2, except that a second non-ionic fluorosurfactant is applied to thepowder coating. The second fluorosurfactant has a pH ranging from about 7 to about 9 and adensity of about 1.1 g / cm3- commercially available as FS-65 from DuPont. The resulting buildingpanel of Comparative Example 1 has 0.02 g / m2of fluorosurfactant applied atop the powdercoating.

[0158] The building panels of Examples 1 and 2 as well as Comparative Examples 1 and 2 werethen compared for oil and dirt repellency according to the follow methodology. A dirt compositionis prepared including peat moss, Portland Cement, calcined kaolinite, and Sno-Brite Clay. TheSno-Brite Clay includes >95 wt.% Kaolin as well as minor amounts of silica (quartz, cristobalite),mica, and titanium dioxide.

[0159] Each of the building panels of Example 1 and Comparative Example 1 are positioned suchthat the powder coated surface faces upward. An amount (0.2 grams) of the dirt composition ofTable 1 is then placed into a plastic cup and held over the powder coated surface, where the plasticcup is tapped allowing the dirt composition to fall naturally onto the upward facing powder coatedsurface of the dirt repellant panel. Except for the dirt composition that is applied to the powdercoated surface, the dirt repellant panel remains untouched. The soiled building panels are then leftfor a period of 24 hours.

[0160] After the period of 24 hours, the building panels are flipped upside down (180°) causingthe powder coated surface to face downward, allowing the loose dirt composition to fall off thepowder coated surface of the dirt repellant panel. The surface of the building panels that areopposite the powder coated surface is then tapped 20 times causing additional dirt composition tofall off the building panels. The building panels are then turned half way back (90°) such that thepowder coated surface of the building panels are facing sideways, followed by tapping the side ofthe building panels 10 times. The building panels are then turned back to the original positionsuch that the powder coated surface is facing upwards, whereby that surface is then measured fora change in color value - i.e. "Delta E" (Δ E), as previously discussed.

[0161] Specifically, the L2, a2, and b2 values are the color values as measured by the MinoltaChroma Meter CR 410 after each sample is soiled by the dirt composition, as previously discussed.The control value for each color test is the same color and construction without any application ofthe dirt composition. The various color readings are taken at three different areas on the sample,and the average Delta E is recorded - as shown in Table 1.Table 1

[0162] As demonstrated by Table 1, the combination of the cationic fluorosurfactant in thetopcoating applied to a powder coating comprising the anionic fluorosurfactant provides anunexpected improvement in dirt and oil repellency of the building panel as compared to other topcoatings applied to powder coatings that comprise a non-ionic fluorosurfactant - as evidenced bya smaller Delta E value - in as little of an amount as 0.02 g / m2.Anti-Soiling Test Protocol of Liquid Fluorosurfactant in Powder Coating

[0163] The following experiment measures the oil and dirt repellency on the major surface of thebuilding panel according to the present invention using liquid-based fluorosurfactants in powdercoatings. In performing this experiment, a series of building panels were prepared with powdercoatings applied thereto. A first building panel (Control 1) was prepared having a powder coatingwith no fluorosurfactant. The building panel of Control 1 does not include a top-coating.

[0164] A second building panel (Example 3) was prepared with a powder coating formed from aprecursor that included a waxy (i.e. 100% solids) anionic fluorosurfactant. The powder coating ofExample 3 was prepared according to the same methodology as the powder coatings of Examples1 and 2 - including the same anionic fluorosurfactant. The building panel of Example 3 does notinclude a top-coating.

[0165] Three additional building panels (Examples 4-6) were prepared with a powder coatingformed from a precursor that included a liquid-based anionic fluorosurfactant. The powdercoatings of Examples 4-6 were prepared by blending together the precursor components (i.e.,polymeric binder, cross-linker, and liquid-based anionic fluorosurfactant) in a blender at atemperature below 120 °F. After blending, the blended precursor mixture passed through anextruder at a temperature ranging from about 90°C to about 110 °C, whereby the liquid carrierpresent on the liquid-based anionic fluorosurfactant was evaporated from the precursor.Subsequently, the resulting extrudate was pelletized into a powder. Each resulting powder is spraycoated onto a first major surface of an aluminum substrate. The coated substrate is then heated toa temperature causing the cross-linker and the polymeric binder to covalently bond, therebyproviding a cross-linked powder coating atop the substrate.

[0166] Two additional building panels (Comparative Examples 3 and 4) were prepared with apowder coating formed from a precursor that included a liquid-based non-ionic fluorosurfactant.The powder coatings of Comparative Examples 3 and 4 were prepared according to the samemethodology as Examples 4-6 except that the liquid based fluorosurfactant is non-ionic instead ofanionic.

[0167] Regarding the building panels of Example 3-6 and Comparative Examples 3 and 4, thespecific amount of liquid-based fluorosurfactant in each precursor mixture was selected such thatthe resulting powder coating contained the same relative amount of solid fluorosurfactant in thefinal powder coating. Therefore, while the solids content of each liquid-based fluorosurfactant ofExamples 3-6 and Comparative Examples 3 and 4 may differ in the precursor, the final buildingpanels provide an accurate side-by-side comparison as the dry (i.e., solid) amount offluorosurfactant between panels is the same.

[0168] The resulting building panels of Control 1, Examples 3-6, and Comparative Example 3 and4 were then subjected the dirt and oil repellency test as set forth with respect to Examples 1 and 2.The results of the dirt and oil repellency test for each building panel is set forth below in Table 2.Table 2As demonstrated by Table 2, the use of liquid-based anionic fluorosurfactants in the powdercoatings of the present invention provide an unexpected improvement in dirt and oil repellency ascompared to other types of non-ionic fluorosurfactants, which is reflected by the low ΔE of thebuilding panels of Examples 4-6 compared to that of Comparative Examples 3 and 4. Furthermore,the incorporation of the liquid-based anionic fluorosurfactants according to the methodology ofthe present invention avoids issues of clumping and improper distribution of the fluorosurfactantthroughout the precursor as demonstrated by the ΔE of the building panels of Examples 4-6, whichis the same if not lower than that of the building panel of Example 3 formed from a solidfluorosurfactant. The successful incorporation of liquid-based fluorosurfactants into a powdercoating composition goes against the previously accepted wisdom in the art, which was to avoidusing liquid-containing components when forming powder coating compositions that are requiredto be solid when applied to a substrate.Anti-Bacterial Testing Protocol

[0169] The anti-bacterial testing protocol was used to prepare and test the building panel samplesof Examples 7-13, Comparative Examples 5-11, and Controls 2-8. Each building panel samplewas prepared by applying a powder coating composition atop a 50 mm x 50 mm metal substrate.Each of the powder coating compositions comprise a blend of polymeric resin precursor, cross10 linker, and pigment and have a solids content of at least 99%.

[0170] The powder coating composition of the present invention (i.e., Examples 7-13) includes anantimicrobial composition of 7 pbw of zinc borate and 0.1 pbw of 2-(4-thiazolyl) benzimidazolebased on 100 parts of the overall powder coating composition. The powder coating compositionof Comparative Examples 5-11 does not include the antimicrobial composition of the presentinvention, but rather an antimicrobial composition of silver nitrate. The powder coatingcomposition of Controls 2-8 included no antimicrobial composition.

[0171] Once applied to the metal substrate, each powder coating composition was heated abovethe curing temperature causing the polymeric resin precursor to react with the cross-linker andform a cross-linked powder coating.

[0172] Several tests were performed to measure the antibacterial efficacy of the cross-linkedpowder coatings. Each test included a total of three Petri dishes, whereby the first Petri dishcontained one of the inventive building panel samples (i.e., one of Examples 7-13), the secondPetri dish contained one of the comparative building samples (i.e., one of Comparative Examples5-11), and the third Petri dish contained one of the control building panel samples (i.e., one ofControls 2-8). Each Petri dish was inoculated with bacteria at specific concentration then coveredwith sterile plastic to spread the inoculum evenly over each sample surface. The samples wereincubated at 35 °C and a relative humidity of 90%. The bacteria concentration was measured ineach Petri dish at an initial time (t = 0) and again after a pre-determined time period of 24 hours (t= 24).

[0173] After the 24-hour time period, the bacterial colonies on each test sample were counted andrecorded. The value of the antimicrobial activity of each sample was calculated according to theformula listed below and recorded as log reduction as follows:90% reduction = 1 log reduction (i.e., 1,000,000 reduced to 100,000 is a 1 log reduction)99% reduction = 2 log reduction (i.e., 1,000,000 reduced to 10,000 is a 2 log reduction)99.9% reduction = 3 log reduction (i.e., 1,000,000 reduced to 1,000 is a 3 log reduction)99.99% reduction = 4 log reduction (i.e., 1,000,000 reduced to 100 is a 4 log reduction)99.999% reduction = 5 log reduction (i.e., 1,000,000 reduced to 10 is a 5 log reduction)

[0174] The performance of the antimicrobial coatings was normalized into an antibacterial activity("R"), which is calculated according to the following:R = (Ut - Uo) - (At - Uo) = Ut - At

[0175] WherebyR: antimicrobial activityUo: average of logarithm numbers of viable bacteria from Control at t = 0Ut: average of logarithm numbers of viable bacteria from Control at t = 24At: average of logarithm numbers of viable bacteria from test sample at t = 24

[0176] According to the present invention, the antimicrobial coating is deemed to have antibacterial effectiveness when the anti-bacterial activity is 2.0 or greater. The results of each bacteriatesting are provided herein.

[0177] Anti-Bacterial Efficacy Against Staphylococcus aureus

[0178] A test measuring the efficacy against the Staphylococcus aureus bacteria was performed ata starting bacteria concentration of 9.7 x 10 CFU / mL. The results of the first test usingStaphylococcus aureus are shown below in Table 3.Table 3

[0179] The antimicrobial coating according to the present invention (Ex. 7) exhibited a 99.99%reduction in bacterial colonies, resulting in an R value of 4.77 - well above the 2.0 threshold forbacterial effectiveness against the Staphylococcus aureus bacteria. The comparative antimicrobialcoating (Comp. Ex. 5) exhibited only an 85% reduction, resulting in an R value of 0.83, well belowthe 2.0 R value threshold.

[0180] The test for efficacy against the Staphylococcus aureus bacteria was repeated at a lowerstarting bacteria concentration of 7.5 x 105 CFU / mL. The results are presented in Table 4.Table 4

[0181] The antimicrobial coating of the present invention (Ex. 8) again exhibited up to a 99.99%reduction in bacterial activity, resulting in an R value of 5.26 against the Staphylococcus aureusbacteria. The comparative antimicrobial coating (Comp. Ex. 6) exhibited only a 97% reduction,resulting in an R value of 1.49, below the 2.0 threshold.

[0182] Anti-Bacterial Efficacy Against Escherichia coli

[0183] A test measuring the efficacy against the Escherichia coli bacteria was performed at astarting bacteria concentration of 7.2 x 105CFU / mL. The results are presented in Table 5.Table 5

[0184] At this concentration, the antimicrobial coating of the present invention (Ex. 9) as well asthe comparative coating (Comp. Ex. 7) both exhibited up to a 99.8% reduction in bacterialcolonies, resulting in an R value of 2.87, which is above the 2.0 threshold for bacterial effectivenessagainst the Escherichia coli bacteria.

[0185] The test for efficacy against the Escherichia coli bacteria was repeated at a higher startingbacteria concentration of 7.6 x 105 CFU / mL. The results are presented in Table 6.Table 6

[0186] The antimicrobial coating of the present invention (Ex. 10) exhibited up to a 99.99%reduction in bacterial activity, resulting in an R value of 6.26 against the Escherichia coli bacteria.However, the comparative antimicrobial coating (Comp. Ex. 8) exhibited only a 58% reduction,resulting in an R value of 0.39, well below the 2.0 R value threshold.

[0187] Anti-Bacterial Efficacy Against Bacillus cereus

[0188] A test measuring efficacy against the Bacillus cereus bacteria was performed at a startingbacteria concentration of 4.1 x 105CFU / mL. The results are presented in Table 7.Table 7

[0189] The antimicrobial coating of Example 11 exhibited up to a 99.5% reduction in bacterialcolonies, resulting in an R value of 2.31 - which is above the 2.0 threshold for bacterialeffectiveness against the Bacillus cereus bacteria. The comparative antimicrobial coating (Comp.Ex. 9) exhibited only a 75% reducing, resulting in an R value of 0.6, well below the 2.0 R valuethreshold.

[0190] Anti-Bacterial Efficacy Against Acinetobachter baumannii

[0191] A test measuring the efficacy against the Acinetobachter baumannii bacteria wasperformed at a starting bacteria concentration of 9.2 x 105 CFU / mL. The results are presented inTable 8.Table 8

[0192] Both the antimicrobial coating of the present invention (Ex. 12) and the comparativecoating (Comp. Ex. 10) exhibited up to a 99.99% reduction in bacterial colonies. However, at anR value of 6.02, the antimicrobial coating of the present invention again out-performed thecomparative antimicrobial coating, which exhibited an R value of 4.2 against the Acinetobachterbaumannii bacteria.

[0193] Anti-Bacterial Efficacy Against Klebsiella pneumoniae

[0194] A test measuring the efficacy against the Klebsiella pneumoniae bacteria was performed ata starting bacteria concentration of 6.4 x 105 CFU / mL. The results are presented in Table 9.Table 9

[0195] Both the antimicrobial coating of the present invention (Ex. 13) and the comparativecoating (Comp. Ex. 11) exhibited up to a 99.99% reduction in bacterial colonies. However, at anR value of 4.44, the antimicrobial coating of the present invention out-performed the comparativeantimicrobial coating, which exhibited an R value of 4.05 against the Klebsiella pneumoniaebacteria.

[0196] Summary of Anti-Bacterial Efficacy

[0197] The anti-bacterial efficacy of each building panel is summarized in the Table 10.Table 10

[0198] As demonstrated by Table 10, the antimicrobial additive of the present invention impartshighly effective broad spectrum bacterial resistance to the powder coatings at range of variousbacteria concentrations, while the comparative antimicrobial additive works against only a select number of bacteria and the comparative antimicrobial additive being effect against those selectbacteria in limited concentrations.

[0199] Anti-Mold Testing Protocol

[0200] The anti-mold protocol was used to prepare and test the sample building panels ofExamples 14, 15, Comparative Example 12, and Control Example 9. Each building panel samplewas prepared by applying a powder coating composition atop a 3" x 4" metal substrate. Each ofthe powder coating compositions had a solids content of at least 99% and comprised a blend ofpolymeric resin precursor, cross-linker, and pigment.

[0201] The powder coating composition of the present invention (i.e., Examples 14 and 15)includes an antimicrobial composition of 7 pbw of zinc borate and 0.1 pbw of 2-(4-thiazolyl)benzimidazole based on 100 parts of the overall powder coating composition. The powder coatingcomposition of Comparative Example 12 does not include the antimicrobial composition of thepresent invention, but rather an antimicrobial composition of silver nitrate. The powder coatingcomposition of Control Example 9 included no antimicrobial composition.

[0202] Each sample was placed in a test chamber that contained soil seeded with fungal sporesthat were allowed to grow. Specifically, the soil was seeded with Aspergillus niger (ATCC#6275); Penicillium citrinum (ATCC# 9849); and Aureobasidium pullulans (ATCC# 9348). Thechamber was held at room temperature (32.5 ± 1°C) and a relative humidity of 95 ± 3% for aperiod of one week. After the period, each sample was removed from the test chamber andobserved. The amount of defacement caused by mold formation on both the front and rear majorsurfaces was observed and measured. The degree of defacement was assigned to a rating scale asset forth in Table 11:Table 11

[0203] The defacement of each sample, as well as control samples which contained powdercoatings applied to a substrate, except the powder coatings did not comprise the antimicrobialcomposition, were observed after each week. The results of the experiment are set forth below inTable 12.Table 12

[0204] As demonstrated by Table 12, the antimicrobial coating composition performs adequatelyagainst mold-growth over the period of 4 weeks against other powder coatings.

Claims

1. An anti-soiling article comprising a composition that includes a powder coating and a fluorocontaining repellent component, wherein the powder coating is formed from polymer resin, cross-linker and anionic fluorosurfactant that is different from the fluoro-containing repellent component; and wherein the anionic fluorosurfactant has a solids content from about 13% to about 15%.

2. The anti-soiling article as claimed in claim 1, wherein the fluoro-containing repellent component is an ionic fluorosurfactant having a pH ranging from about 3 to about 6.

3. The anti-soiling article as claimed in any one of claims 1 to 2, wherein the fluoro-containing repellent component is cationic.

4. The anti-soling article as claimed in claim 1, wherein the fluoro-containing repellent component is an ionic fluorosurfactant having a pH ranging from about 9 to about 11.

5. The anti-soiling article as claimed in any one of claims 1 or 4, wherein the fluoro-containing repellent component is anionic.

6. The anti-soiling article as claimed in any one of claims 1 to 5, wherein the fluoro-containing repellent component comprises fluoropolymer.

7. The anti-soiling article as claimed in claim 6, wherein the fluoropolymer is selected from fluorinate acrylic copolymer, fluorinated acrylic alkylamino copolymer, and combinations thereof.

8. An article comprising a powder coating applied to a substrate, the powder coating formed from a precursor composition comprising polymeric resin, cross-linker, and a blend of liquid carrier and fluorosurfactant; and wherein the fluorosurfactant is an anionic fluorosurfactant having a solids content from about 13% to about 15%, based on the total weight of the precursor composition.

9. The article as claimed in claim 8, wherein the liquid carrier is water.

10. A powder coating precursor composition comprising a blend of: polymeric resin, cross-linker, and a liquid-based surfactant comprising a liquid carrier and a fluorosurfactant; and wherein the liquid carrier is present in an amount ranging from about 10 wt. % to about 75 wt. % based on the total weight of the liquid carrier and the fluorosurfactant in the liquidbased carrier; and wherein the liquid-based surfactant is present in an amount ranging from about 0.05 wt. % to about 4 wt. % based on the total weight of the blend.

11. The powder coating precursor as claimed in claim 10, wherein the liquid carrier is present in an amount ranging from about 30 wt. % to about 75 wt. % based on the total weight of the liquid-based surfactant.

12. The powder coating precursor as claimed in claim 10, wherein the fluorosurfactant has a pH ranging from about 9 to about 11.

13. The powder coating precursor as claimed in claim 10, wherein the liquid carrier is water.

14. The powder coating precursor as claimed in claim 10, wherein the blend is substantially free of fluoropolymer.

15. The powder coating precursor as claimed in claim 10, wherein the polymeric resin is chemically reactive with the cross-linker.