Latent catalyst and coating compositions including the same

Abstract

The present disclosure provides a latent catalyst for use in two-component crosslinkable coating systems, and preferably two-component Michael addition chemistry. The latent catalyst is a salt having a structure of BR+A- wherein BR+ has a structure configured, in one approach, to be deprotonated forming a carbene with the B moiety thereof including a 5-, 6-, or 7-membered heterocycle including two or more heteroatoms with an intermediate carbon atom and R thereof represents one or more substituents on the heterocyclic ring and selected from hydrogen or a substituted or unsubstituted alkyl, vinyl, aryl, alkaryl group, hydrocarbyl group, or combinations thereof. The A- moiety may be a carbonate anion, a bicarbonate anion, or a carbamate anion.

Description

LATENT CATALYST AND COATING COMPOSITIONS INCLUDING THE SAMECROSS REFERENCE TO RELATED APPLICATION

[0001] This application claims priority under 35 U.S.C 119(e) to U.S. Provisional Application No. 63 / 534,611, filed on August 25, 2023. The entire contents of the aforementioned application is incorporated herein.TECHNICAL FIELD

[0002] This disclosure relates to latent catalysts and to coating compositions including such latent catalysts, and in particular, latent carbene catalysts for use in two-component crosslinkable coating systems.BACKGROUND

[0003] Typically, crosslinkable two-component compositions are coating compositions where the components are stored separately and mixed prior to use. The two components are often highly reactive and will begin to crosslink as soon as they are mixed. It is conventional to include a catalyst in such coating systems to increase the rate of the crosslinking reaction between the two components.

[0004] The crosslinking reaction may be base-catalyzed or acid-catalyzed. Base-catalyzed systems are sometimes preferred because they are capable of a fast cure. However, because of the rapid rate of cure, prior base-catalyzed compositions can only be used for a relatively short period of time after the components are mixed, defined as the pot-life of the coating composition. In some base-catalyzed systems, viscosity increases so rapidly that the coating starts to cure before it can be fully applied to a surface, and accordingly, these systems are of limited practical use.

[0005] For waterborne systems where viscosity may not be a good indicator for pot-life, the hardness and / or the gloss level of applied coatings at various times may be used a measure of pot life. Due to concerns regarding the use of volatile organic compounds (VOC) in coatings, high solids systems with low solvent content or even waterborne systems substantially free of solvent are oftentimes preferred. However, such systems present several additional challenges with regard to balancing pot-life, hardness / gloss, and kinetics of cure or dry speed. For example, ahigh solids composition typically includes less solvent that can evaporate when the coating is applied, and as a result, the pot-life is much lower than preferred.

[0006] On the other hand, the increase in reaction rate when the coating is applied is also reduced with less solvent in the system, leading to slower cure. Thus, a combination of rapid cure and long pot-life is often challenging to achieve for two-component, high-solids solvent borne coating systems and / or for waterborne systems where the reaction may occur in the dispersion phase. Thus, a further challenge in two-component crosslinkable systems, both solvent borne and waterborne, using latent catalysts is the cure kinetics at room temperature or lower bake conditions of about 100°C or less. Prior systems using latent base catalysts oftentimes required too high of an activation temperature for such systems to have cure kinetics practicable at the lower room temperature or low bake conditions. In some prior systems, the latent catalyst may also be blocked to provide desired pot life. However, blocked catalysts also provide challenges. For instance, blocked catalysts tend to deposit or leave salts in a dried coating film that, in some circumstances, may degrade coating performance. In other instances, only the anionic portion of a blocked catalyst after the de-blocking acts as a base for catalyzing the reaction tending to limit the cure mechanisms.SUMMARY

[0007] In one approach or embodiment, the present application describes a latent catalyst for use in two-component crosslinkable coating systems, and in one aspect, a latent carbene catalyst and, in another aspect, a latent N-heterocyclic olefin catalyst. In aspects of this approach, the latent carbene catalyst includes a salt having a structure of BR A (Formula I); wherein the BR cation thereof has a structure configured to be deprotonated forming a carbene with the B moiety thereof including a 5-, 6-, or 7-membered heterocycle including two or more heteroatoms with an intermediate carbon atom and R moiety thereof being one or more substituents on the heterocycle selected from hydrogen or a substituted or unsubstituted alkyl group, vinyl group, aryl group, alkaryl group, hydrocarbyl group, or combinations thereof; and wherein the A' anion is a carbonate anion, a bicarbonate anion, a carbamate anion, a carboxylate, or combinations thereof. In other aspects, the BR+cation has a structure configured to form a N-heterocyclic olefin including a 5-, 6-, or 7-membered heterocycle including two or more heteroatoms with an intermediate carbon atom and R moiety thereof being one or more substituents on the257068427 2heterocycle selected from hydrogen or a substituted or unsubstituted alkyl group, vinyl group, aryl group, alkaryl group, hydrocarbyl group, or combinations thereof.

[0008] In other approaches or embodiments, the latent catalyst, the latent carbene catalyst, or the latent N-heterocyclic olefin catalyst of the previous paragraph may be combined with one or more optional features or embodiments in any combination. These optional features or embodiment may include one or more of the following: wherein R is a hydrocarbyl substituent with one or more carbon atoms thereof optionally replaced with a moiety selected from -O-, -S-, -C(O)-, -C(O)O-, -OC(O)O-, -S(O)-, -SO2-, -N(Rx)-, -Si(-Rx)(Ry)-, or combinations thereof, wherein Rxand Ryare each, independently, selected from hydrogen, a hydrocarbyl group, or a substituted hydrocarbyl group; and / or wherein the BR+cation is a 1,3-di-substituted imidazolium compound, tautomer thereof, or derivative thereof; and / or wherein the 5-, 6-, or 7-membered heterocycle of the BR cation includes a fused bi-cyclic compound, a bis-heterocyclic compound, or combinations thereof; and / or wherein the two or more heteroatoms are nitrogen atoms and wherein the intermediate carbon atom is configured to form the carbene; and / or wherein the BR+cation has the structure of Formula II or tautomer thereof:(Formula II) wherein each of Ri, R2, R3, and R4 is, independently, hydrogen (R1 and R2 excluded) or a substituted or unsubstituted alkyl, vinyl, aryl, or alkaryl group and R’ is hydrogen or a -CHRsRe group, while either Rs or Re is independently hydrogen, a substituted or unsubstituted alkyl, aryl, or alkaryl group, in some occasions, Rs and Re can form a ring or Rs or Re, independently forms a ring with either Ri or R2; and / or wherein Ri and R4, along with the atoms to which they are attached, combine to form a substituted or unsubstituted aliphatic, aromatic, or heterocyclic ring structure; and / or wherein R2 and R3, along with the atoms to which they are attached, combine to form a substituted or unsubstituted aliphatic, aromatic, or heterocyclic ring structure; and / or wherein R3 and R4, along with the atoms to which they are attached, combine to form a substituted or unsubstituted aliphatic, aromatic, or heterocyclic ring structure; and / or wherein at least one of Ri, R2, , and R4 is a Cl to C25 saturated or unsaturated alkyl group; and / or wherein at least one of Ri, R2, , and R4 includes a substituted or unsubstituted aromatic moiety having 6 to 18 carbon atoms selected from a phenyl, a naphthyl, a phenanthryl, ananthracyl, a biphenyl, or a terphenyl group; and / or wherein the BR+cation has the structure of Formula Ila or tautomer thereof:(Formula Ila) wherein each of Ri, R2, R3, and R4 is, independently, hydrogen or a substituted or unsubstituted alkyl, vinyl, aryl, or alkaryl group, each R’ is, independently, hydrogen or a -CHR5R6 group, while either Rs or Re is independently hydrogen, a substituted or unsubstituted alkyl, aryl, or alkaryl group, in some occasions, Rs and Re can form a ring or Rs or Re, independently forms a ring with either Ri or R2, and R is a hydrocarbyl group with one or more carbon atoms thereof optionally replaced with a moiety selected from -O-, -S-, -C(O)-, -C(O)O-, -OC(O)O-, -S(O)-, - SO2-, -N(Rx)-, -Si(-Rx)(Ry)-, or combinations thereof, wherein Rxand Ryare each independently selected from hydrogen, a hydrocarbyl group, or a substituted hydrocarbyl group; and / or wherein Ri and R4, along with the atoms to which they are attached, combine to form a substituted or unsubstituted aliphatic, aromatic, or heterocyclic ring structure; and / or wherein R2 and R3, along with the atoms to which they are attached, combine to form a substituted or unsubstituted aliphatic, aromatic, or heterocyclic ring structure; and / or wherein R3 and R4, along with the atoms to which they are attached, combine to form a substituted or unsubstituted aliphatic, aromatic, or heterocyclic ring structure; and / or wherein BR+A is 1 ,3-dialkyl imidazolium bicarbonate or carbonate salt; and / or wherein the A' anion has the structure of Formula III(Formula III) wherein Rs is hydrogen, alkyl, aryl, alkaryl, hydrocarbyl, or combinations thereof; and / or wherein Rs is a hydrocarbyl group and wherein, optionally, one or more carbon atoms thereof is replaced with a moiety selected from -O-, -S-, -C(O)-, -C(O)O-, -OC(O)O-, -S(O)-, -SO2-, -N(Rx)-, -Si(-Rx)(Ry)-, or combinations thereof, wherein Rxand Ryare each independently selected from hydrogen, a hydrocarbyl group, or a substituted hydrocarbyl group; and / or wherein the A’ anion has the structure of Formula IVwherein Re and R7 are each, independently, hydrogen or linear or branched alkyl, aryl, alkaryl, hydrocarbyl, or combinations thereof; and / or wherein one or both of Re and R7 is, independently, a hydrocarbyl group and wherein, optionally, one or more carbon atoms thereof is replaced with a moiety selected from -O-, -S-, -C(O)-, -C(O)O-, -OC(O)O-, -S(O)-, -SO2-, -N(Rx)-, Si(-Rx)(Ry)-, or combinations thereof, wherein Rxand Ry are each independently selected from hydrogen, a hydrocarbyl group, or a substituted hydrocarbyl group; and / or wherein Re and R7 including the nitrogen atom to which they are attached combine to form a ring structure; and / or wherein the ring structure is a heterocyclic ring structure; and / or wherein the heterocyclic ring structure is a succinimide ring structure.

[0009] In another approach or embodiments, the present disclosure includes a crosslinkable two-component waterborne or solvent borne coating composition. In aspects of this embodiment, the composition includes a water-based or an organic solvent-based carrier fluid; a first ingredient or portion thereof having at least two protons that can be activated to form a Michael carbanion donor; a second ingredient or portion thereof having at least two ethylenically unsaturated functionalities each activated by an electron-withdrawing group to form a Michael acceptor; and the latent catalyst, the latent carbene catalyst, or the latent N-heterocyclic olefin catalyst as described by any embodiment of this Summary.

[0010] The crosslinkable two-component waterborne or solvent borne coating composition of the previous paragraph may be combined with one or more optional features or embodiments in any combination. These optional features or embodiments may include one or more of the following: wherein the coating composition further includes pigments, matting agents, fillers, wetting agents, defoamers, rheological modifiers, ultraviolet (UV) light stabilizers, dispersing agents, flow and leveling agents, optical brighteners, gloss additives, radical inhibitors, radical initiators, adhesion promoters, plasticizers, waxes, or combinations thereof; and / or wherein the composition includes about 0.01 to about 20 weight percent of the latent carbene catalyst; and / or wherein the composition includes a weight ratio of the Michael carbanion donor to the Michael acceptor of about 1 :3 to about 3: 1, preferably about 1 :2 to about 2: 1, and more preferably about 1 : 1.5 to about 1.5: 1; and / or wherein the carrier fluid includes about 5 to 100 weight percent water / solvent / water-solvent mixture based on the total weight of the carrier fluid.SELECTED DEFINITIONS

[0011] Unless otherwise specified, the following terms as used herein have the meanings provided below.

[0012] As used herein, the term “organic group” means a hydrocarbon group (with optional elements other than carbon and hydrogen, such as oxygen, nitrogen, sulfur, and silicon) that is classified as an aliphatic group, cyclic group, or combination of aliphatic and cyclic groups (e.g., alkaryl and aralkyl groups). The term “aliphatic group” means a saturated or unsaturated linear or branched hydrocarbon group. This term is used to encompass alkyl, alkenyl, and alkynyl groups, for example. The term “alkyl group” means a saturated linear or branched hydrocarbon group including, for example, methyl, ethyl, isopropyl, t-butyl, heptyl, dodecyl, octadecyl, amyl, 2-ethylhexyl, and the like. The term “alkenyl group” means an unsaturated, linear or branched hydrocarbon group with one or more carbon-carbon double bonds, such as a vinyl group. The term “alkynyl group” means an unsaturated, linear or branched hydrocarbon group with one or more carbon-carbon triple bonds. The term “cyclic group” means a closed ring hydrocarbon group that is classified as an alicyclic group or an aromatic group, both of which can include heteroatoms. The term “alicyclic group” means a cyclic hydrocarbon group having properties resembling those of aliphatic groups. The term “Ar” refers to a divalent aryl group (i.e., an arylene group), which refers to a closed aromatic ring or ring system such as phenylene, naphthylene, biphenylene, fluorenylene, and indenyl, as well as heteroarylene groups (i.e., a closed ring hydrocarbon in which one or more of the atoms in the ring is an element other than carbon (e.g., nitrogen, oxygen, sulfur, etc.)). Suitable heteroaryl groups include furyl, thienyl, pyridyl, quinolinyl, isoquinolinyl, indolyl, isoindolyl, triazolyl, pyrrolyl, tetrazolyl, imidazolyl, pyrazolyl, oxazolyl, thiazolyl, benzofuranyl, benzothiophenyl, carbazolyl, benzoxazolyl, pyrimidinyl, benzimidazolyl, quinoxalinyl, benzothiazolyl, naphthyridinyl, isoxazolyl, isothiazolyl, purinyl, quinazolinyl, pyrazinyl, 1-oxidopyridyl, pyridazinyl, triazinyl, tetrazinyl, oxadiazolyl, thiadiazolyl, and so on. When such groups are divalent, they are typically referred to as “heteroarylene” groups (e g., furylene, pyridylene, etc.)

[0013] A group that may be the same or different is referred to as being “independently” something. Substitution is anticipated on the organic groups of the compounds of the present invention. As a means of simplifying the discussion and recitation of certain terminology used throughout this application, the terms “group” and “moiety” are used to differentiate betweenchemical species that allow for substitution or that may be substituted and those that do not allow or may not be so substituted. Thus, when the term “group” is used to describe a chemical substituent, the described chemical material includes the unsubstituted group and that group with O, N, Si, or S atoms, for example, in the chain (as in an alkoxy group) as well as carbonyl groups or other conventional substitution. Where the term “moiety” is used to describe a chemical compound or substituent, only an unsubstituted chemical material is intended to be included. For example, the phrase “alkyl group” is intended to include not only pure open chain saturated hydrocarbon alkyl substituents, such as methyl, ethyl, propyl, t-butyl, and the like, but also alkyl substituents bearing further substituents known in the art, such as hydroxy, alkoxy, alkylsulfonyl, halogen atoms, cyano, nitro, amino, carboxyl, etc. Thus, “alkyl group” includes ether groups, haloalkyls, nitroalkyls, carboxyalkyls, hydroxy alky Is, sulfoalkyls, etc. On the other hand, the phrase “alkyl moiety” is limited to the inclusion of only pure open chain saturated hydrocarbon alkyl substituents, such as methyl, ethyl, propyl, t-butyl, and the like.

[0014] The term “component” refers to any compound that includes a particular feature or structure. Examples of components include compounds, monomers, oligomers, polymers, and organic groups contained there.

[0015] The term “double bond” is non-limiting and refers to any type of double bond between any suitable atoms (e.g., C, O, N, etc.).

[0016] The term “triple bond” is non-limiting and refers to any type of triple bond between any suitable atoms.

[0017] “Catalyst” as used herein is a latent catalyst, a latent carbene catalyst, or a latent N- heterocyclic olefin catalyst in the form of a salt having a structure of BR A wherein BR+is a cation thereof and A' is an anion thereof. As discussed more below, the BR+cation, in one appaoch, has a structure configured to be deprotonated forming a carbene with the B moiety thereof including a 5-, 6-, or 7-membered heterocycle including two or more heteroatoms with an intermediate carbon atom. In another approach, the BR+cation has a structure configured to form a N-heterocyclic olefin. The R moiety thereof represents one or more substituents on the heterocyclic ring and may be selected from hydrogen or a substituted or unsubstituted alkyl, vinyl, aryl, alkaryl group, hydrocarbyl group, or combinations thereof. The latent carbene catalysts herein are preferably non-blocked meaning the catalysts and the compositions herein are preferably free-of traditional blocking agent that commonly require high temperatures todeblock (such as metal salts (to form carbene-metal complexes), carbodiimide, mono or dicarboxylic acids, sulfonic acid and its derivatives, phosphoric acid or phosphonic acid and their organic analogs, halogenated compounds, and the like blocking agents). Unless the context of discussion herein suggests otherwise, free-of a blocking agent means about 0.1 weight percent or less, about 0.05 weight percent or less, about 0.01 weight percent or less, or most preferably no functional amounts of any blocking agents.

[0018] The phrase “Michael addition,” as used herein refers to the nucleophilic addition of a carbanion or other nucleophile to an electron-deficient ethylenically unsaturated compound, such as an a,0-unsaturated carbonyl compound, for example. The abbreviated form “MA” is used interchangeably herein with the term “Michael addition.” An exemplary reaction scheme for a Michael addition reaction may be as follows:(MA Donor) (MA acceptor)In the reaction schematic shown above, BR+A' is one of the latent catalysts, the latent carbene catalysts, or the latent N-heterocyclic olefin catalysts as described herein that reacts with the Michael addition (MA) donor by deprotonation to form a carbanion for a subsequent addition reaction with the (MA) acceptor. In some approaches, the R’ and R” groups are, independently, electron-withdrawing acyl and / or cyano groups as discussed more below.

[0019] The term “resin composition,” as used herein refers to the resin-containing portion of the composition. The resin composition may include one or more resins. Suitable examples include, without limitation, MA donors, MA acceptors, non-functional resins, and resins with functionality other than those required Michael addition.

[0020] By “Michael addition acceptor” or “MA acceptor” or “Michael acceptor” refers to a molecule or portion thereof having at least one MA acceptor functional group.

[0021] By “Michael addition donor” or “MA donor” or “Michael carbanion donor” or “Michael donor” refers to a molecule or portion thereof having at least one MA donor functional group.

[0022] By “MA acceptor / donor” is meant a molecule having at least one Michael addition (MA) acceptor functional group and at least one Michael addition (MA) donor functional group.

[0023] The term “crosslinker” refers to a molecule capable of forming a covalent linkage between polymers or between two different regions of the same polymer.

[0024] The term “self-crosslinking,” when used in the context of a self-crosslinking polymer, refers to the capacity of a polymer to enter into a crosslinking reaction with itself and / or another molecule of the polymer, in the absence of an external crosslinker, to form a covalent linkage therebetween. Typically, this crosslinking reaction occurs through reaction of complimentary reactive functional groups present on the self-crosslinking polymer itself or two separate molecules of the self-crosslinking polymer.

[0025] The term “dispersion” in the context of a dispersible polymer refers to the mixture of a dispersible polymer and a carrier. The term “dispersion” is intended to include the term “solution.”

[0026] The term “ambient temperature,” as used herein refers to the surrounding temperature in a typical indoor or room temperature environment, i.e. a temperature of about 68°F to about 77°F (about 20°C to about 25°C).

[0027] The term “low-bake temperature” or “low-cure temperature” refers to a temperature of about 100°C or less, or about 80°C or less and, preferably about 60 to about 100°C, and more preferably about, about 60 to about 80°C.

[0028] The term “on”, when used in the context of a coating applied on a surface or substrate, includes both coatings applied directly or indirectly to the surface or substrate. Thus, for example, a coating applied to a primer layer overlying a substrate constitutes a coating applied on the substrate.

[0029] The term "volatile organic compound" ("VOC") refers to any compound of carbon, excluding carbon monoxide, carbon dioxide, carbonic acid, metallic carbides or carbonates, and ammonium carbonate, which participates in atmospheric photochemical reactions. Typically, volatile organic compounds have a vapor pressure equal to or greater than 0. 1 mm Hg. As used herein, "volatile organic compound content" ("VOC content") means the weight of VOC per volume of the coating solids, and is reported, for example, as kilograms (kg) of VOC per liter. VOC as reported herein is measured, for example, according to ASTM D2369-90. As used herein, waterbore systems are low VOC (e.g., about 0.5 kg / L or less), zero VOC, or may be substantially free of VOCs.

[0030] Unless otherwise indicated, the term “polymer” includes both homopolymers and copolymers (i.e., polymers of two or more different monomers).

[0031] As used herein, without the need for, without substantial levels of, in the absence of, or substantially free of, devoid of or free-of generally means (unless apparent from the context of the discussion) the coating compositions herein have less than about 1 weight percent, in other approaches, less than about 0.5 weight percent, in other approaches, less than about 0.2 weight percent, and in yet other approaches, none of the particular component or additive. In addition, (unless apparent from the context of the discussion), significantly free with respect to an ingredient means about 0.5 weight percent or less, substantially free with respect to an ingredient means about 0.2 weight percent or less, substantially completely free of an ingredient means about 0.1 weight percent or less, and completely free of an ingredient means none of such ingredient or at least no functional amount of such ingredient.

[0032] When referring to a polymer, oligomer, or copolymer, and a particular monomer or reactant is described, it is also intended that such discussion refers to the resulting monomer unit or associated repeating unit when polymerized within the polymer, oligomer, or copolymer. Likewise, when a monomer unit or repeating unit of a polymer, oligomer, or copolymer is described, the corresponding monomer or reactant is also contemplated by this disclosure. As used herein, the terms polymer or copolymer are interchangeable unless the context of discussion suggests otherwise. A polymer or copolymer herein typically have a weight average molecular weight of about 1,000 to about 40,000 and an oligomer typically has a molecular weight below 1000. As used herein, unless the context suggests otherwise, the term “polymer” includes both homopolymers (repeating units are derived from the same monomer) and copolymers (i.e., polymers of two or more different monomers). Similarly, “oligomer” includes both homo-oligomers and co-oligomers.

[0033] As used herein, (meth)acrylate monomer(s) or monomer unit(s) include both acrylate monomer(s) and monomer unit(s) and methacrylate monomer(s) and monomer unit(s) as well as functionalized (meth)acrylate monomer(s) or monomer unit(s) suitable for incorporation into the functionalized polymers or oligomers disclosed herein. Functional moieties may also bear other crosslinking groups, photo-reactive groups, anti-fouling agents, light absorbers, anti-corrosion agents, and the like as needed for a particular application or use.

[0034] The term “comprises” and variations thereof do not have a limiting meaning where these terms appear in the description and claims.

[0035] The terms “preferred” and “preferably” refer to embodiments of the invention that may afford certain benefits, under certain circumstances. However, other embodiments may also be preferred, under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, and is not intended to exclude other embodiments from the scope of the invention.

[0036] As used herein, “a,” “an,” “the,” “at least one,” and “one or more” are used interchangeably. Thus, for example, a coating composition that comprises “an” additive can be interpreted to mean that the coating composition includes “one or more” additives.

[0037] Also herein, the recitations of numerical ranges by endpoints include all numbers subsumed within that range (e g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, 5, etc.). Furthermore, disclosure of a range includes disclosure of all subranges included within the broader range (e.g., 1 to 5 discloses 1 to 4, 1.5 to 4.5, 1 to 2, etc.).DETAILED DESCRIPTION

[0038] The present description provides a latent catalyst, such as a latent carbene catalyst and / or a latent N-heterocyclic olefin catalyst, for use in two-component crosslinkable coating systems, and preferably latent carbene catalyst systems including carbonate, bicarbonate, and / or other nitrogen-heterocylic salts that can undergo degradation to release carbon dioxide to generate carbenes that are suitable for use in two-component Michael addition chemistry. This disclosure also describes crosslinkable two-composition waterborne or solvent borne coating compositions including the latent carbene catalysts herein. The catalysts and compositions herein can extend pot-life and improve the cure kinetics of two-component Michael addition chemistry and are suitable, for instance, during room temperature and low-bake curing conditions.

[0039] Latent Catalyst

[0040] In one approach or embodiment, the latent catalyst is a salt having a structure of BR+A' (Formula I) that is configured to form a latent carbene catalyst or a latent N-heterocylic olefin catalyst.

[0041] In one aspect of Formula I, the BR+cation thereof has a structure configured to be deprotonated forming a carbene unit with the B moiety thereof including a 5-, 6-, or 7-membered heterocycle including two or more heteroatoms with an intermediate carbon atom. In another aspect of Formula I, the BR+cation thereof has a structure configured to be form aN- heterocyclic olefin with the B moiety thereof including a 5-, 6-, or 7-membered heterocycle including two or more heteroatoms with an intermediate carbon atom. The R moiety thereof represents one or more substituents on the heterocyclic ring and may be selected from hydrogen or a substituted or unsubstituted alkyl, vinyl, aryl, alkaryl group, hydrocarbyl group, or combinations thereof. For instance, the R group may be one or more hydrocarbyl groups and, optionally, with one or more carbon atoms thereof replaced with a moiety selected from -O-, -S-, -C(O)-, -C(O)O-, -OC(O)O-, -S(O)-, -SO2-, -N(Rx)-, -Si(-Rx)(Ry)-, or combinations thereof, wherein Rxand Ryare each, independently, selected from hydrogen, a hydrocarbyl group, or a substituted hydrocarbyl group.

[0042] In embodiments, the carbene catalysts of the present disclosure undergo degradation to release carbon dioxide and water or alcohol to generate the carbenes. As understood, the carbenes herein are molecules including a carbon atom with a valence of two and having two unshared valence electrons. Preferably, the two or more heteroatoms of the B moiety are nitrogen atoms and wherein the intermediate carbon atom in the ring structure is configured to form the carbene. Such catalysts extend pot-life and promote desired cure kinetics of two- component coating systems at room temperature and low-bake (about 100°C or less) cure conditions.

[0043] In one approach, the latent catalysts herein include the BR+cation that may have the general structure of Formula II or a tautomer thereof(Formula II)

[0044] In approaches or embodiments, each of Ri, R2, R3, and R4 of Formula II may be, independently, hydrogen or a substituted or unsubstituted alkyl, vinyl, aryl, or alkaryl group and R’ is hydrogen or a -CHR5R6 group, while either Rs or Re is independently hydrogen, a substituted or unsubstituted alkyl, aryl, or alkaryl group, in some occasions, R5 and Re can form a ring or Rs or Re, independently forms a ring with either Ri or R2. In some approaches, Ri andR4, along with the atoms to which they are attached, combine to form a substituted or unsubstituted aliphatic, aromatic, or heterocyclic ring structure. Likewise, R2 and R3, along with the atoms to which they are attached, may also combine to form a substituted or unsubstituted aliphatic, aromatic, or heterocyclic ring structure and / or R3 and R4, along with the atoms to which they are attached, may also combine to form a substituted or unsubstituted aliphatic, aromatic, or heterocyclic ring structure. In yet another embodiment, at least one of Ri, R2, R3, and / or R4 (or any combinations thereof) is a Cl to C25 saturated or unsaturated alkyl group. In further embodiments, at least one of Ri, R2, R3, and / or R4 (or any combination thereof) may also include a substituted or unsubstituted aromatic moiety having 6 to 18 carbon atoms selected from a phenyl, a naphthyl, a phenanthryl, an anthracyl, a biphenyl, or a terphenyl group. In one particular approach, the BR+cation is a 1,3 -di -substituted imidazolium compound, tautomer thereof, or derivative thereof. In other approaches, the 5-, 6-, or 7-membered heterocycle of the BR+moiety includes a fused bi-cyclic compound, a bis-heterocyclic compound, or combinations thereof.

[0045] In another approach or embodiment, the BR+cation of Formula I has the structure of Formula Ila or tautomer thereof(Formula Ila)

[0046] In Formula Ila, each of Ri, R2, 3, and R4 is, independently, hydrogen or a substituted or unsubstituted alkyl, vinyl, aryl, or alkaryl group, each R’ is, independently, hydrogen or -CHR5R6 group, while either Rs or Re is independently hydrogen, a substituted or unsubstituted alkyl, aryl, or alkaryl group, in some occasions, Rs and Re can form a ring or Rs or Re, independently forms a ring with either Ri or R2, and R of Formula Ila is a hydrocarbyl group with one or more carbon atoms thereof optionally replaced with a moiety selected from -O-, -S-, -C(O)-, -C(O)O-, -OC(O)O-, -S(O)-, -SO2-, -N(Rx)-, -Si(-Rx)(Ry)-, or combinations thereof, and where Rxand Ryare each independently selected from hydrogen, a hydrocarbyl group, or a substituted hydrocarbyl group.

[0047] Similar to the structure of Formula II, the Ri and R4, substituents of Formula Ila, along with the atoms to which they are attached, may combine to form a substituted or unsubstituted aliphatic, aromatic, or heterocyclic ring structure. Likewise, R2 and R3 of FormulaIla, along with the atoms to which they are attached, may also combine to form a substituted or unsubstituted aliphatic, aromatic, or heterocyclic ring structure, and / or R3 and R4 of Formula Ila, along with the atoms to which they are attached, may also combine to form a substituted or unsubstituted aliphatic, aromatic, or heterocyclic ring structure.

[0048] In one embodiment, the catalysts of Formula II or Ila are configured to deprotonate to form a carbene as exemplified by the activation mechanism show below in reaction scheme A:R = H, C 1 -C20 linear or branched alkyl (Reaction scheme A)

[0049] In another embodiment, the the catalysts of Formula II or Ila are configured to form a N-heterocyclic olefin as exemplified by the activation mechanism show below in reaction scheme B :(Reaction scheme B)

[0050] Exemplary latent carbene catalysts are provided the following, but not exhaustive, listing of structures:

[0051] In Formula I, the A" moiety thereof is an anion preferably in the form of a carbonate anion, a bicarbonate anion, a carboxylate, or a carbamate anion. In preferred approaches, the A’ anion of the latent carbene catalysts herein, in one form, may be selected form a carbonate anion or a bicarbonate anion and, in such context, have a general structure of Formula III0A R

[0052] ’0 O'5(Formula III) wherein Rs is hydrogen, alkyl, aryl, alkaryl, hydrocarbyl, or combinations thereof. In some embodiments, Rs may be a hydrocarbyl group and wherein, optionally, one or more carbon atoms thereof is replaced with a moiety selected from -O-, -S-, -C(O)-, -C(O)O-, -OC(O)O-, -S(O)-, -SO2-, -N(Rx)-, -Si(-Rx)(Ry)-, or combinations thereof, wherein Rxand Ryare each independently selected from hydrogen, a hydrocarbyl group, or a substituted hydrocarbyl group.

[0053] In other embodiments, the A’ anion may have the structure of Formula IV(Formula IV) wherein Re and R7 are each, independently, hydrogen or linear or branched alkyl, aryl, alkaryl, hydrocarbyl, or combinations thereof. In some embodiments, one or both of Re and R7 is, independently, a hydrocarbyl group and wherein, optionally, one or more carbon atoms thereof is replaced with a moiety selected from -O-, -S-, -C(O)-, -C(O)O-, -OC(O)O-, -S(O)-, -SO2-, - N(Rx)-, -Si(-Rx)(Ry)-, or combinations thereof, wherein Rxand Ry are each independently selected from hydrogen, a hydrocarbyl group, or a substituted hydrocarbyl group.

[0054] In some optional approaches, Re and R7 of Formula IV, including the nitrogen atom to which they are attached, may combine to form a ring structure. The ring structure of Formula IV may be a heterocyclic ring structure, and preferably may be a succinimide ring structure.

[0055] Exemplary carbonate or bicarbonate anions of Formula III may include, but are not limited, to the following anion structures:wherein R and Rn of the structure above may hydrogen, alkyl, aryl, alkaryl, hydrocarbyl, or combinations thereof. In approaches, the R or Rn of the structures above is a hydrocarbyl groupand wherein, optionally, one or more carbon atoms thereof is replaced with a moiety selected from -O-, -S-, -C(O)-, -C(O)O-, -OC(O)O-, -S(O)-, -SO2-, -N(RX)-, -Si(-Rx)(Ry)-, or combinations thereof, wherein Rxand Ry are each independently selected from hydrogen, a hydrocarbyl group, or a substituted hydrocarbyl group

[0056] Exemplary carbamate anions of Formula IV may include, but are not limited to, the following anion structures:wherein R and R’ in the above structures may be, independently, hydrogen or a substituted or unsubstituted alkyl group, such as a Cl to C25, Cl to C12, Cl to C6, or Cl to C4 substituted or unsubstituted alkyl group.

[0057] In one particular embodiment, the latent carbene catalyst of BR A' is 1 ,3-dialkyl imidazolium bicarbonate or carbonate salt. The latent carbene catalysts herein are configured to degrade by releasing water or alcohol and carbon dioxide to form the carbene catalyst that can extend the pot-life and / or promote the cure kinetics of a two-component Michael addition system that activates at room temperature or low-bake conditions as discussed above.

[0058] In one approach or embodiment, the latent carbene catalyst systems are fairly stable in their pure forms or solution states at room temperature and can be activated after application as the generated carbon dioxide leaves the surface so the equilibrium shifts to the right and more and more neutral bases or ionic liquids are generated to catalyze the reaction. The cure temperature may be about 5°C to about 100°C, preferably about 10°C to about 80°C, and more preferably about 15°C to about 60°C.

[0059] In further embodiments, certain latent carbene catalysts of this disclosure may also exhibit an anti-microbial effect and / or provide resistance to bacteria, fungi, and / or algae in some circumstances. For instance, the latent carbene catalysts herein having at least one substituentwith a long alkyl chain, such as a CI O or greater alkyl chain (in other embodiments, a CIO to C20 alky chain, a C10 to C18 alkyl chain, or a C10 to C16 alkyl chain) are effective provide an anti-microbial effect as a compound and / or in a coating composition. In other embodiments, the latent carbene catalysts may also be polymerized and / or functionalized with other reactive groups (e.g., hydroxy groups) such that the anti -microbial latent carbene catalysts herein can be converted to a polymer form and / or attached to polymer networks in the coating compositions such that the catalysts are substantially non-leachable, which enables any anti-microbial impact to last longer.

[0060] In embodiments, for example, latent carbene catalysts that exhibit anti-microbial effects include those of Formula II or Ila above that have one or more of the R1-R4 substituents with a CIO or greater alkyl group, such as a CIO to C20 alkyl group, a CIO to Cl 8 alkyl group, or a C10 to C16 alkyl group. Specific examples of antimicrobial latent carbene catalysts are provided below and also shown in the Example section below:As shown in the Examples below, the efficacy of the anti-microbial effect of the latent carbene catalysts herein can be tuned by the chain length of the substituents, and if needed, can be functionalized into a polymer form or functionalized with other substituents / reactive groups (e.g. hydroxy groups) enabling the catalysts to be polymerized and / or attached to a polymer network formed within the coating compositions that extends the life of the anti -microbial activity. While the catalysts herein having anti -microbial activity are primarily configured for the Michael addition reactions described herein, such catalysts may also be used in other coating chemistries, such as polyurethane, epoxy, and the like, to provide similar anti-microbial activity.

[0061] Coating Composition

[0062] In another embodiment or approach of this disclosure, a coating composition including a water-based or an organic solvent-based carrier fluid, a latent catalyst as describedhereinabove, and a resin system having a Michael addition reactants. In approaches, the composition includes at least one ingredient, reactant, or portion thereof having at least two protons that can be activated to form a Michael carbanion donor or MA donor, i.e. a molecule having at least one MA donor functional group, and a second ingredient, reactant, or portion thereof having at least two ethylenically unsaturated functionalities each active by an electronwithdrawing group to form a Michael acceptor at least one MA acceptor, i.e. a molecule having at least one MA donor functional group. In one approach, malonate and acetoacetate-based systems may be used as the MA donors and acrylate-based systems may be used as the MA acceptor. Other polymers may be polyester acrylate systems, polyurethane systems, acrylic dispersion, and epoxy systems as needed for a particular application.

[0063] Suitable examples of MA donors include, but are not limited to, dialkyl mal onates (e g., dimethyl malonate, diethyl malonate, and the like), cyanoacetates (e g., methyl cyanoacetate, ethyl cyanoacetate, and the like), chloroacetates, acetoacetates, propionyl acetates, malononitrile, acetonitrile, acetylacetone, dipropionyl methane, and the like, and mixtures or combinations thereof. Preferred examples of MA donors include, but are not limited to, malonate or acetoacetate group containing oligomeric and polymeric compounds such as, for example, polyesters, polyurethanes, polyacrylates, epoxy resins, polyamides, and polyvinyl resins containing malonate or acetoacetate functional groups in the main chain, pendant, or both.

[0064] In an embodiment, the MA donor described herein is at least one polymeric resin having Michael addition donor functional groups. In an aspect, the backbone of the MA donor includes a polyester backbone, a polyurethane backbone, a polyacrylate backbone, an epoxy backbone, or a polyamide backbone. In a preferred aspect, the backbone of the MA donors may be aliphatic or aromatic. Suitable aromatic epoxy resins that can be functionalized to act as MA donors include, but are not limited to, MA functionalized bisphenol An epoxy and novolac epoxy resins. In an aspect, the epoxy resins can be functionalized by reaction with diketene, transesterification with an alkyl acetoacetate or dialkyl malonate, esterification of the epoxy resin with malonic acid or a monoester or acid functional malonated polyester, and the like.

[0065] Suitable examples of MA acceptors include, but are not limited to, esters of (meth)acrylic acid, i.e. a (meth)acrylate functional compound derived from the reaction of an hydroxyl functional compound (i) with (meth)acrylic acid or its ester derivatives (ii), wherein the hydroxyl functional compound can be mono-, di-, or polyfunctional and has as a backbone thatcontains an aliphatic, cycloaliphatic or aromatic chain, a (poly)epoxy, (poly)ether, (poly)ester for example (poly)caprolactone, (poly)alkyd, (poly)urethane, (poly)amine, (poly)amide, (poly)carbonate, (poly)olefm, (poly)siloxane, (poly)acrylate, halogen (e.g. fluorine), a melaminederivative, copolymers of any of them, and the like, and mixtures and combinations thereof.

[0066] Preferred examples of such MA acceptors include, without limitation, the multifunctional acrylate derivatives of glycidyl epoxy resins (e.g., diglycidyl ether of bisphenol A) and phenolic novolac epoxy resins. Exemplary MA acceptors may include an aromatic epoxy acrylate. In an aspect, the MA acceptor is multifunctional, i.e. the MA acceptor has a functionality of preferably 2 or more. Suitable examples of MA acceptors with aromatic epoxy backbone include, without limitation, acrylated glycidyl epoxy resins (e.g., diglycidyl ether of bisphenol A (BPA)), and acrylated novolac epoxy resins. In one aspect, the MA acceptor described herein is a difunctional BPA epoxy acrylate.

[0067] Without limiting to theory, it is believed that a multifunctional MA donor and a multifunctional MA acceptor will react via a Michael addition reaction as described above, and thereby help improve cure speed, crosslink density, and hardness development for the coating compositions described herein. The improved cured and increased crosslink density will lead to improved performance characteristics.

[0068] In an embodiment, the MA donor and the MA acceptor are mixed together to obtain a coating composition. In an aspect, the MA donor and MA acceptor will each independently be present in an amount of about 5 to about 50 percent by weight, preferably about 10 to about 40 percent by weight, based on the total weight of the coating composition. In an aspect, stoichiometric index of MA donor acidic protons to MA acceptor unsaturated groups is about 10: 1 to about 0.1 : 1, preferably about 5: 1 to about 0.2: 1, more preferably about 1.5: 1 to about 0.7:1 or in other approaches, about 1 :3 to about 3: 1, about 1 :2 to about 2: 1, or about 1 : 1.5 to about 1.5: 1.

[0069] In an embodiment, the amount of latent catalyst used herein may vary depending on the properties of the coating composition. In one approach, the composition includes about 0.001 to 1 meq catalyst per gram of resin solids, more preferably 0.02 to 0.07 meq per gram of resin solids. In other approaches, the compositions herein may include about 0.01 weight percent to about 20 weight percent of the latent catalysts, preferably about 0.1 weight percent to about 10weight percent, more preferably about 0.5 weight percent to about 5 weight percent of the latent catalysts herein.

[0070] Optionally, to extend open-time and potlife, one or more additional components may be included, such as, for example, one or more acidic X'-H groups, where X' is N, P, O, S, or C, where the X' anion is a MA donor capable of reaction with the MA acceptor, and the pKa of the X'-H group is lower than the pKa of the majority MA donor (e.g. acetoacetate-functional resin), preferably more than 2 units lower. Suitable examples include, without limitation, ethylacetoacetate, benzotriazole, succinimide, acetyl acetone, or 1,2,4-triazolem, and mixtures or combinations thereof. In one aspect, the open time extender may be benzotri azole, and if present in the compositions herein, in an amount of about 0.5 to about 5 weight percent or, more preferably, about 0.5% to about 1.5%, based on the total weight of resin solids.

[0071] In another embodiment, the coating compositions described herein may optionally include an acid-scavenging or pH-buffering component. Suitable examples include, without limitation, metal oxide (e.g., zinc oxide, nanoparticular zinc oxide, magnesium oxide, calcium oxide, strontium oxide, barium oxide, lanthanum oxide, ytterbium oxide, zirconium oxide, and the like), mixed metal oxide (e.g., MgO-TiO2, and the like), zeolites (e.g., cesium-exchanged zeolite, X,Y-Cs-occluded zeolite, and the like), modified mesoporous materials (e.g., MgO- coated mesoporous silica (SB A- 15), amino-functionalized mesoporous silica (MCM-41), mesoporous silicon oxynitride, and the like), metal hydroxide (e.g., calcium hydroxide, Na / NaOH / A12O3, Na / MgO, and the like), metal nitride, metal oxynitride (e.g., silicon, oxynitride, aluminophosphate oxynitride, zirconophosphate oxynitride, calcined NaNO3, and the like), metal carbonate (e.g., calcium carbonate, sodium carbonate, potassium carbonate, and the like), metal silicate (e.g., calcium silicate, calcium borosilicate, magnesium silicate, Mg-Al hydrotalcite, chrysotile, and the like), metal carboxylate salts (e.g., titanium acetyl acetate, and the like), organic metal compounds (e.g., organic zirconate, weak base titanate, tetraalkyl titanate, and the like), amines (e.g., guanidine, aziridine, amidine, triethanolamine, DMP30, and the like), imides (e.g., carbodiimide, and the like), diaza-bicyclo compounds (e.g., DABCO, and the like), and mixtures or combinations thereof.

[0072] Accordingly, in an embodiment, the coating compositions described herein are applied over an acidic substrate, such as for example, a metal substrate with a pretreatment applied thereon. Suitable examples of pretreatment include, without limitation, iron phosphate,zinc phosphate, silane, zirconium, and the like. Many other pretreatments are known in the metal pretreatment industry. In one aspect, the metal substrates herein may have an iron phosphate treatment applied thereon.

[0073] In some embodiments, the coating compositions described herein optionally include one or more adhesion promoters. By “adhesion promoter” is meant an additive that is included in a coating composition to form primary bonds with either the substrate surface or with any previously applied coating or pretreatment. As used herein, the one or more adhesion promoters function to improve dry adhesion, wet adhesion, or preferably, both, of a primer composition to the substrate. Suitable examples of adhesion promoters useful with the coating compositions described herein include, without limitation, silanes, silicones, catalytic metals, and the like. Of these, organosilane adhesion promoters or coupling agents are preferred. In an embodiment, if present in the coating composition, the adhesion promoter is present in an amount of about 2 to about 20 weight percent, more preferably about 5 to about 15 weight percent, and even more preferably about 7 to about 10 percent by weight, based on the total weight of resin solids in the coating composition.

[0074] The coating composition described herein may also include other optional ingredients that do not adversely affect the coating composition or a cured coating composition resulting therefrom. Such optional ingredients are typically included in a coating composition to enhance coating aesthetics; to facilitate manufacturing, processing, handling, and application of the composition; and to further improve a particular functional property of a coating composition or a cured coating composition resulting therefrom. For example, the composition described herein may optionally include fillers, catalysts, lubricants, pigments, surfactants, dyes, colorants, toners, coalescents, extenders, anticorrosion agents, flow control agents, thixotropic agents, dispersing agents, antioxidants, adhesion promoters, light stabilizers, and mixtures thereof, as required to provide the desired film properties. Each optional ingredient is preferably included in a sufficient amount to serve its intended purpose, but not in such an amount to adversely affect a coating composition or a cured coating composition resulting therefrom.

[0075] In an embodiment, the composition described herein may include resin components that do not undergo Michael addition reaction, in addition to the MA donors and MA acceptors described herein. These additional resin components may have no reactive functional groups or have reactive functional groups that undergo reactions other than the Michael addition reaction.In some approaches, the resins may have other cure chemistries, such as urethane, epoxy, alkyd, thermal cure chemistry and the like so long as such systems do not materially interfere with the Michael addition reactions described herein.

[0076] For example, in an aspect, the composition described herein may include a coreactant, such as, without limitation, an amine co-reactant. The presence of such a co-reactant helps improve certain performance characteristics of the composition described herein, such as corrosion resistance. In an aspect, where the composition described herein is a two-part composition, the co-reactant may be included in the first part (part A) or in the second part (part B) of the composition. In a preferred aspect, the co-reactant is an amine co-reactant present in part B of the composition. If present, the amine co-reactant is present in an amount of about 0.01 to about 1 weight percent, in other approaches about 0.05 to about 0.1 weight percent, based on the total weight of the resin solids.

[0077] In an embodiment, the coating composition described herein may include a solvent. Suitable solvents may be aqueous, organic, or mixtures thereof. Suitable examples of organic solvents include, without limitation, aliphatic solvents, aromatic and / or alkylated aromatic solvents (e.g., toluene, xylene, and the like), alcohols (e.g., isopropanol), esters (e.g., methoxy propanol acetate, butyl acetate, isobutyl acetate, and the like), ketones (e.g., methyl ethyl ketone, methyl amyl ketone, and the like), glycol ethers, glycyl ether esters, and mixtures or combinations thereof. In an aspect, the coating composition described herein has a low volatile organic compound (VOC) content, preferably less than 400 g / L, more preferably less than 300 g / L, and most preferably less than 250 g / L, and more preferably less than about 200 g / L. The coating compositions herein may have about 10 to about 30 weight percent of the solvent, in other approaches, about 15 to about 25 weight percent of the solvent, and in yet other approaches, about 18 to about 22 weight percent of the solvent. The solvent or carrier fluids herein may be about 5 to about 100 weight percent water.

[0078] In an embodiment, the coating composition described herein may be used as a primer or may be part of a primer formulation. When used as a primer or in a primer formulation, the composition described herein may be applied over an untreated substrate, a pretreated substrate, a substrate with a temporary coating applied thereon, and the like. In a preferred aspect, the composition described herein is applied over a metal substrate with an acidic pretreatment, preferably a phosphate pretreatment. In some approaches, Michael addition chemistry is notnecessarily suitable for acidic surfaces and in such context, a primer system (PUD, epoxy, and the like) may be applied upon the acidic surface first to form a surface suitable for the Michael addition chemistries herein.

[0079] In an embodiment, the coating composition described herein may be used as a topcoat. In an aspect, a first coating (such as a primer, for example) is applied over an untreated substrate, a pretreated substrate, a substrate with a temporary coating applied thereon, and the like. Then, a second coating (such as a topcoat, for example) is applied over the primer. In an aspect, the second coating is applied only after the first coating has fully dried or cured. In an alternative aspect, the second coating is applied over the first coating before the first coating has fully dried or cured. Where the coating composition is intended for exterior usage and / or intended to be a weatherable coating, for example as a topcoat or direct-to-metal (monocoat) application, it is preferred that the resin backbone of all MA acceptors and MA donors within the composition includes less than 100%, preferably less than 75%, and more preferably less than 50% of an epoxy backbone.

[0080] In an embodiment, the coating composition described herein may be used as a primer, and any topcoat may be applied over the described primer. In an aspect, the topcoat composition is also obtained by a Michael addition reaction. The Michael addition-derived topcoat may be the same or different than the Michael addition-derived primer composition described herein. In another aspect, the topcoat composition may be a component not derived by a Michael addition reaction, but known in the art as a suitable topcoat material, such as a polyurethane topcoat, for example. Michael addition-derived topcoats are known in the art, as described in U.S. Patent No. 8,962,725, for example, incorporated herein by reference. In other approaches, any primer used herein generally is not Michael addition-derived but rather from other chemistries like epoxy, urethane, and the like.

[0081] The compositions described herein also show improved shelf life and potlife. In an aspect, the compositions described herein have optimal shelf-life and demonstrate no loss of cure-response or any viscosity increase after storage for up to one week or more at temperatures for water based Michael addition systems. For solvent based Michael addition system, the potlife can be several hours to a couple of days. In another aspect, the coating compositions described herein also demonstrate optimal potlife, where the composition takes preferably longer than 60 minutes, more preferably longer than 120 minutes, to double in viscosity after mixing.Alternatively, the potlife of solvent based systems can be judged by gel time that is the time length during which the liquid coating will stop to flow in a container.

[0082] The coating composition of the present invention may be applied to a substrate either prior to, or after, the substrate is formed into an article. In an aspect, the coating composition described herein may be applied on a variety of substrates. Suitable examples include, without limitation, natural and engineered buildings and building materials, freight containers, flooring materials, walls, furniture, other building materials, motor vehicles, motor vehicle components, aircraft components, trucks, rail cars and engines, bridges, water towers, cell phone tower, wind towers, radio towers, lighting fixtures, statues, billboard supports, fences, guard rails, tunnels, pipes, marine components, machinery components, laminates, equipment components, appliances, and packaging. Exemplary substrate materials include, without limitation, wood, plastics, thermosets, metals, metal alloys, intermetallic compositions, metal-containing composites, and combinations of these. Exemplary metal substrates include, without limitation, aluminum, steel, weathering steel, and stainless steel. In a preferred aspect, the substrate is steel, preferably steel with a pretreatment applied thereon.

[0083] The coating composition described herein may be applied by any method known in the art. Standard methods of application include, without limitation, such as by brushing, spraying, spin coating, roll coating, curtain coating, dipping, gravure coating, bell application, and / or the like. In the case of two-component thermoset substrates, the coating may be applied via in-mold processes. When the coating composition is applied by spray methods, both conventional air or air-assisted spray equipment, or airless spray equipment may be used. Both electrostatic and non-electrostatic equipment may be used.

[0084] The coating thickness of a particular layer and the overall coating system will vary depending upon the coating material used, the substrate, the coating application method, and the end use for the coated article. When used as a primer applied over an untreated or pretreated metal substrate, the thickness of the applied coating film is preferably about 0.05 to about 20 mils (about 1.27 to about 500 microns), more preferably about 0.4 to about 40 mil (about 10 to about 100 micron), and even more preferably about 1.0 to about 2.5 mils (about 25 to about 70 microns).

[0085] In an embodiment, the composition described herein provides a cured coating with optimal cure and corrosion resistance. In an aspect, after the coating is applied to a substrate, itis cured within 1 to 10 minutes at a bake temperature of 100°C or less, where the term “cured” means at least partially, preferably fully, cross-linked. As a measure of optimal cure, the cured coating demonstrates, in one approach, a pencil hardness of preferably least H, more preferably at least 2H, even more preferably at least 5H (as measured pursuant to ASTM D3363). In another approach, a 6 mil wet drawdown of a coating composition including the catalysts herein applied on a cold rolled steel substrate, when cured at room temperature of about 25°C, achieves a Konig Hardness of about 10 to about 150 after at least 7 days. Hardness can be determined using pencil hardness or pendulum hardness to judge the cure extent of coating and measured pursuant to ASTM D4366. In further approaches, a coating composition herein when a 6 mil wet drawdown is applied to a cold rolled steel substrate, when cured at 80°C for about 30 minutes, achieves a Konig Hardness of about 30 to about 150 after at least 7 days.EXAMPLES

[0086] The following examples are illustrative of exemplary embodiments of the disclosure. In these examples, as well as elsewhere in this application, all ratios, parts, and percentages are by weight unless otherwise indicated. It is intended that these examples are being presented for the purpose of illustration only and are not intended to limit the scope of the invention disclosed herein.

[0087] PART A - CATALYST EXAMPLES

[0088] EXAMPLE 1

[0089] An example of a latent carbene catalyst in the form of 3 -ethyl- 1 -methyl imidazolium bicarbonate was prepared as follows: 20.00 g of l-ethyl-3-methylimidazolium chloride (hereinafter noted as [EMIM]C1) and 14.34 g of KHCO3 were dried under vacuum for 3 hours. The imidazolium chloride then was dissolved in 200 mL of methanol and to the solution KHCO3 was added. The resulted mixture was stirred at room temperature for 48 hours and filtered through a celite pad. The methanol was removed to offer a mixture of light brown liquid as the final product. Yield was quantitative. Nuclear Magnetic Resonance (NMR) showed that the product has a structure consistent with l-ethyl-3-methyl-lH-imidazol-3-ium hydrogen carbonate.

[0090] EXAMPLE 2

[0091] The procedure of example 1 was followed except that l-butyl-3-methyl-lH-imidazol-3-ium bromide was used in place of l-ethyl-3-methyl-lH-imidazol-3-ium chloride offering a product in a form of an off-white sticky solid. Quantitative yield was achieved. NuclearMagnetic Resonance (NMR) showed that the product has a structure consistent with l-methyl-3- butyl-lH-imidazol-3-ium hydrogen carbonate.

[0092] EXAMPLE 3

[0093] l-methyl-3 -propyl- lH-imidazol-3-ium methyl carbonate as below was purchased fromAldrich and used as received.

[0094] EXAMPLE 4

[0095] Step 1 - To a clear glass jar, 20 g of 1 -methylimidazole and 30.83 g of benzyl chloride were added and the mixture was stirred at room temperature for 5 minutes. Then the temperature was increased to 120 C and kept for 2 hrs. After cooling down to room temperature, the resulted material is the final product in a form of white solid which was used directly without further treatment. Quantitative yield was achieved.

[0096] Step 2 - The procedure of example 1 was followed except that l-benzyl-3-methyl- lH-imidazol-3-ium chloride and ethanol were used in place of l-ethyl-3-methyl-lH-imidazol-3- ium chloride and methanol, respectively. The product is in a form of a slightly yellow liquid. Ayield of 21 .2 g was achieved. Nuclear Magnetic Resonance (NMR) showed that the product has a structure consistent with 3-benzyl-l-methyl-lH-imidazol-3-ium hydrogen carbonate.HCO3-

[0097] EXAMPLE 5

[0098] Step 1 - The procedures of step 1 in example 4 were followed except that l-chloro-2- (2-chloroethoxy)ethane (molar ratio to 1-methyl imidazole is 0.5: 1) was used in place of benzyl chloride (molar ratio to 1-methyl imidazole in example 4 is 1 : 1) to offer a product in a form of light brown sticky material. 37.42 g of 3,3'-(oxybis(ethane-2,l-diyl))bis(l-methyl-lH-imidazol- 3-ium) chloride was obtained and used directly for the next step without further treatment.

[0099] Step 2 - The product from step 1 was dissolved in 100 mL of methanol in a glass jar and a solution of 13.67 g of potassium hydroxide (2 equiv.) dissolved 50 mL methanol was added. A white precipitate formed overtime and the reaction was kept stirring at room temperature overnight. The solids were filtered off and the filtrate was collected which was used directly for the next step without further treatment. The product is in a form of light brown solution of 3,3'-(oxybis(ethane-2,l-diyl))bis(l-methyl-lH-imidazol-3-ium) hydroxide.

[0100] Step 3 - The product from step 2 was put into an aerosol can with the capillary dip tube removed. The can was sealed and filled with carbon dioxide at 180 psi. It was kept at room temperature overnight and the pressure was released. The can was cut open and the resulted solution was collected. The removal of solvent offered a light brown liquid as the final product. Yield: 40.76 g. Nuclear Magnetic Resonance (NMR) showed that the product has a structure consistent with 3,3'-(oxybis(ethane-2,l-diyl))bis(l-methyl-lH-imidazol-3-ium) hydrogen carbonate.

[0101] EXAMPLE 6

[0102] The procedures of example 4 were followed except that 1 -butyl bromide was used in place of benzyl chloride and 3-butyl-l-methyl-lH-benzo[d]imidazol-3-ium bromide in place of l-benzyl-3-methyl-lH-imidazol-3-ium chloride in step 2. The product is in a form of white solids and 11.0 g was obtained. Nuclear Magnetic Resonance (NMR) showed that the product has a structure consistent with 3 -butyl- 1 -methyl- lH-benzo[d]imidazol-3-ium hydrogen carbonate.HCO3-

[0103] EXAMPLE 7

[0104] The procedures of example 4 were followed except that l-chloro-2-(2- chloroethoxy)ethane was used in place of benzyl chloride in step 1 and 3,3'-(oxybis(ethane-2,l- diyl))bis(l-methyl-lH-benzo[d]imidazol-3-ium) chloride in place of l-benzyl-3 -methyl- 1H- imidazol-3-ium chloride in step 2. The final product is in a form of off-white solids and 10.3 g was obtained. Nuclear Magnetic Resonance (NMR) showed that the product has a structure consistent with 3,3'-(oxybis(ethane-2,l-diyl))bis(l-methyl-lH-benzo[d]imidazol-3-ium) hydrogen carbonate.

[0105] EXAMPLE 8

[0106] 16.33 g of 1 -methylimidazole, 21.35 g of dimethyl carbonate and 6.96 g of methanol were added into a pressure tube. The resulted mixture was heated in 250 F oven for 24 hrs (3*8 hrs). The resulted solution was cooled down to room temperature and light brown precipitates appeared. The mixture was poured into -500 m of acetone and more precipitates formed. The solids were collected by filtration and the filtrate was discarded. The product was dried under vacuum for 8 hr to offer the final product in the form of white solids. 18.2 g was obtained.Nuclear Magnetic Resonance (NMR) showed that the product has a structure consistent with l,3-dimethyl-lH-imidazol-3-ium methyl carbonate.

[0107] EXAMPLE 9

[0108] The procedures of example 4 were followed except that 1,2-dimethyl imidazole was used in place of 1-methyl imidazole in step 1 and 3-benzyl-l,2-dimethyl-lH-imidazol-3-ium chloride in place of l-benzyl-3 -methyl- lH-imidazol-3-ium chloride in step 2. The final product is in a form of white solids and 16 g was obtained. Nuclear Magnetic Resonance (NMR) showed that the product has a structure consistent with 3 -benzyl- 1,2-dimethyl- lH-imidazol-3-ium

[0109] EXAMPLE 10

[0110] The procedures of example 4 were followed except that l-methyl-lH-l,2,4-triazole was used in place of 1 -methyl imidazole in step 1 and 4-benzyl-l -methyl- 1H-1, 2, 4-triazol-4-ium chloride in place of l-benzyl-3-methyl-lH-imidazol-3-ium chloride in step 2. The final product is in a form of rosy paste. 16 g was obtained. Nuclear Magnetic Resonance (NMR) showed that the product has a structure consistent with 4-benzyl-l -methyl- 1H-1, 2, 4-triazol-4-ium hydrogen carbonate

[0111] EXAMPLE 11

[0112] Step 1- 20.95 g of 3-benzyl-l-methyl-lH-imidazol-3-ium chloride (from step 1 of example 4) was dissolved in 20 g of methanol in a glass jar. To the resulting solution, a premade solution of 6.73 g KOH in 15 g of methanol was added under stirring. White precipitates appeared and the reaction was kept at room temperature for overnight. The resulted mixture was filtered and washed with methanol three times. The filtrate was collected. 101 g of clear solution was obtained as the final product (19 wt% of 3-benzyl-l-methyl-lH-imidazol-3-ium hydroxide).

[0113] Step 2 - To a glass jar containing 30 g of 3-benzyl-l-methyl-lH-imidazol-3-ium hydroxide methanol solution (19.0 wt%) was added 13.49 g of dimethyl carbonate. The solution was stirred at room temperature over the weekend. The resulted solution was used directly without further treatment. By calculation, the 3-benzyl-l-methyl-lH-imidazol-3-ium methyl carbonate concentration is 17.1 wt%.

[0114] EXAMPLE 12

[0115] The procedures of example 11 were followed except that 3 -butyl- 1 -methyl- 1H- imidazol-3-ium chloride and ethanol were used in place of 3 -benzyl- 1 -methyl- lH-imidazol-3- ium chloride and methanol, respectively, in step 1 and 3 -butyl- 1 -methyl- lH-imidazol-3-ium hydroxide ethanol solution in place of 3-benzyl-l-methyl-lH-imidazol-3-ium hydroxide methanol solution in step 2. 62.3 g of 3-butyl-l-methyl-lH-imidazol-3-ium ethyl carbonate ethanol solution was obtained as the final product with a concentration of 14.7 wt%.

[0116] EXAMPLE 13

[0117] The procedures in example 1 were followed except that 1 ,3 -bis(2,6- diisopropylphenyl)-lH-imidazol-3-ium chloride was used in place of l-ethyl-3- methylimidazolium chloride. After filtration, the filtrate was used directly without removing the solvent. 88.7 g of l,3-bis(2,6-diisopropylphenyl)-lH-imidazol-3-ium hydrogen carbonate methanol solution was obtained with a concentration of 11.7 wt%.

[0118] EXAMPLE 14

[0119] The procedures of example 11 were followed except that 1 ,3 -bis(2,6- diisopropylphenyl)-lH-imidazol-3-ium chloride and ethanol were used in place of 3-benzyl-l- methyl-lH-imidazol-3-ium chloride and methanol, respectively, in step 1 and 1 ,3-bis(2,6- diisopropylphenyl)-lH-imidazol-3-ium hydroxide ethanol solution in place of 3-benzyl-l- methyl-lH-imidazol-3-ium hydroxide methanol solution in step 2. 20.3 g of l,3-bis(2,6- diisopropylphenyl)-lH-imidazol-3-ium ethyl carbonate ethanol solution was obtained as the final product with a concentration of 21.6 wt%.

[0120] EXAMPLE 15

[0121] The procedures in example 1 were followed except that 1 ,3 -bis(2,6- diisopropylphenyl)-4,5-dihydro-lH-imidazol-3-ium chloride was used in place of 1 -ethyl-3- methylimidazolium chloride. After filtration, the filtrate was used directly without removing the solvent. 28.62 g of l,3-bis(2,6-diisopropylphenyl)-4,5-dihydro-lH-imidazol-3-ium hydrogen carbonate methanol solution was obtained with a concentration of 18 wt%.

[0122] EXAMPLE 16

[0123] The procedures in example 1 were followed except that l,3-dimesityl-lH-imidazol-3- ium chloride was used in place of l-ethyl-3-methylimidazolium chloride. After filtration, the filtrate was used directly without removing the solvent. 77.97 g of l,3-dimesityl-lH-imidazol-3- ium hydrogen carbonate methanol solution was obtained with a concentration of 11.7 wt%. l,3-dimesityl-lH-imidazol-3-ium hydrogen carbonate

[0124] EXAMPLE 17

[0125] The procedures of example 5 were followed except that 1 -benzyl- IH-imidazole and benzyl chloride (molar ratio 1: 1) were used in the place of 1-methyl imidazole and l-chloro-2-(2- chloroethoxy)ethane (molar ratio 1:0.5), 1, 3 -dibenzyl- lH-imidazol-3-ium chloride in placed of 3,3'-(oxybis(ethane-2,l-diyl))bis(l-methyl-lH-imidazol-3-ium) chloride and the molar ratio of potassium hydroxide and the chloride is 1 :1 in step 2, and l,3-dibenzyl-lH-imidazol-3-ium hydroxide in place of 3,3'-(oxybis(ethane-2,l-diyl))bis(l-methyl-lH-imidazol-3-ium) hydroxide in step 3. After the solution was collected in step 3, the solvent was not removed and the 1,3- dibenzyl-lH-imidazol-3-ium hydroxide ethanol solution was used directly without further treatment. Yield: 63.0 g, 24.7 wt%.

[0126] EXAMPLE 18

[0127] The procedures of example 5 were followed except that 1 -bromodecane (molar ratio to 1-methyl imidazole is 1 : 1) was used in the place of l-chloro-2-(2-chloroethoxy)ethane (molarratio to 1-methyl imidazole is 0.5:1) in step 1, 3-decyl-l-methyl-lH-imidazol-3-ium bromide in place of 3,3'-(oxybis(ethane-2,l-diyl))bis(l-methyl-lH-imidazol-3-ium) chloride and the molar ratio of potassium hydroxide and the bromide is 1 : 1 in step 2, and 3-decyl-l-methyl-lH- imidazol-3-ium hydroxide in place of 3,3'-(oxybis(ethane-2,l-diyl))bis(l-methyl-lH-imidazol-3- ium) hydroxide in step 3. After the solution was collected in step 3, the solvent was not removed and the 3-decyl-l-methyl-lH-imidazol-3-ium hydrogen carbonate ethanol solution was used directly without further treatment. Yield: 58.8 g, 30.6 wt%.I lCOf

[0128] EXAMPLE 19

[0129] The procedures of example 4 were followed except that 1 -vinyl imidazole and 1- bromododecane were used in the place of 1-methyl imidazole and benzyl chloride in step 1, and 3-decyl-l-vinyl-lH-imidazol-3-ium bromide and ethanol in place of l-benzyl-3-methyl-lH- imidazol-3-ium chloride and methanol in step 2. After the filtration in step 2, the solvent was not removed and the 3-dodecyl-l-vinyl-lH-imidazol-3-ium hydrogen carbonate ethanol solution was used directly without further treatment. Yield: 36.64 g, 44.43 wt%.

[0130] EXAMPLE 20

[0131] 15.00 g of 1 -methylimidazole and 23.37 g of dimethyl carbonate were added into in pressure tube. The tube was sealed and heated to 90 C and kept for 3 days. The resulted mixture was filtered and washed with acetone three times to offer an off-white solid. Yield: 10.4 g, 40.6%. Nuclear Magnetic Resonance (NMR) showed that the product has a structure consistent with l,3-dimethyl-lH-imidazol-3-ium-2-carboxylate.

[0132] PART B - RESIN EXAMPLES

[0133] For waterborne applications, we used Acure AQ 620-100 from Allnex which is a malonate & acrylate functional non-ionic polyurethane dispersion resin with an optimized ratio of Michael Donor and Acceptor groups as one of the main binders to evaluate the catalysts. Commercial waterborne acrylate dispersions that are developed for waterborne UV coatings and normally have high acid numbers can be used as Michael acceptor resins. Nonionic / low acid Michael donor or acceptor containing dispersions can be prepared separately to demonstrate the efficacy and application scope of the catalysts. In some cases, solvent based Michael addition resins can be used for waterborne applications if they can be emulsified.

[0134] For solvent-based applications, solvent based Acure resins from Allnex can be used. Examples of Michael Donor resins are Acure™ 510-100, 102, 170, 172, 174, 190, 200, 270, 300, 302, 370, 372, 375, and 400. Michael Acceptor resins are Acure™ 550-100, 105, 200, and 405. Acrylate monomers or oligomers from other UV resin companies like IGM, Sartomer, Dymax, BASF, Miwon, Rahn etc. can be used as Michael acceptor resins as well.

[0135] PART C - COATING EXAMPLES

[0136] Evaluation of the efficacy of the inventive catalysts in a commercial resin at room temperature:

[0137] The blocked carbene catalyst of Example 1 was incorporated at 1.6 weight percent into Acure AQ 620-100 from Allnex according to the formula in Table 1. All other catalysts were used equivalently to 1.6 weight percent example 1 based on their molecular weight. The dispersion was mixed, and 6 mil wet drawdowns were applied on cold rolled steel substrates. The coatings were dried at room temperature (25°C) evaluated for Konig pendulum hardness (ASTM D4366) at different times. Results are provided in Table 2 below.

[0138] Table 1Model formula to evaluate catalystsComponent AmountAcure AQ 620-100 30.0 gExample 1 0.48 g in 2.0 g of water

[0139] Table 2Coating Konig pendulum hardness after drying at room temperature and pot-life catalyst Hardness @ day 1 Hardness @ day 7 pot-lifeExample 1 87 108 >7Example 2 70 116 >7Example 3 93 124 >7Example 4 17 96 >1Example 5 25 44 >7Example 6 8 67 >7Example 7 24 60 >7Example 8 7 31 >7Example 9 12 44 >1Example 10 23 42 >1Example 11 47 72 >7Example 12 68 103 >7Example 13 105 129 >7Example 14 107 132 >1Example 15 78 98 >1Example 16 114 130 >1Example 17 48 93 >7Example 18 54 95 >7Example 19 20 27 >1Example 20 3 30 >7[EMIM]C1 no cure no cure n / a[BzMIM]0H 22 44 <1 blank no cure no cure n / aThe pot-life was evaluated by coatings prepared at day 1 and 7 with the same dispersion and the resulted coatings were cured at room temperature. If the day 7 hardness is over 80% of that of the original coating, the pot-life is good.[EMIM]C1: l-ethyl-3-methylimidazol-3-ium chloride;[BzMIM]OH: l-benzyl-3-methylimidazol-3-ium hydroxide

[0140] The results summarized in Table 2 demonstrated that the blocked bases can cure the water-based Michael addition resins at room temperature and provide higher efficacy or longer pot-life or both compared with their parent compounds.

[0141] Evaluation of exemplary blocked carbene catalysts at low-bake condition

[0142] The two formulas listed in Table 3 were used to demonstrate the benefits of the invented catalysts that can cure the coatings at low-bake conditions. [EMIM]C1 (e.g., l-ethyl-3- methylimidazol-3-ium chloride) is the parent compound of example 1 and equal moles are used for comparison. The applied coatings were cured at the following conditions: cured at room temperature for seven days; flash at room temperature for 1 h and baked at 80 °C for 30 min and cured at room temperature for the rest of time; cured at room temperature for 4 h followed by baked at 80 °C for 30 min and then cured at room temperature for the rest of time; cured at room temperature for 1 day followed by baked at 80 °C for 30 min and then cured at room temperature for the rest of time; cured at room temperature for 5 days followed by baked at 80 °C for 30 min and then cured at room temperature for the rest of time. The results are list in Table 4.

[0143] Table 3Formulas to demonstrate low-bake cureAcme 620-100 30.00 g 30.0 gExample 1 0.48 g in 2.0 g of water[EMIMJC1 0.41 g in 2.0 g of water

[0144] The results in table 4 show that the coatings with example 1 can be cured at low bake conditions at different stages with a faster speed. For comparison, the coatings with the parent compound [EMIM]C1 did not cure the coating at all conditions.

[0145] Table 4Cured at room temperature for 7 daysHardness @ day 1 Hardness @ day 5 Hardness @ day 7Example 1 55 56 63[EMIMJC1 No cure No cure No cureFlash at room temperature for 1 hour, baked at 80 °C for 30 min and cured at room temperature for the rest of the timeHardness @ day 1 Hardness @ day 5 Hardness @ day 7Example 1 101 80 75[EMIMJC1 No cure No cure No cureCured at room temperature for 4 hour, baked at 80 °C for 30 min and cured at room temperature for the rest of the timeHardness @ day 1 Hardness day 5 Hardness @ day 7Example 1 106 89 88[EMIMJC1 No cure No cure No cureCured at room temperature for 1 day, baked at 80 °C for 30 min and cured at room temperature for the rest of the timeHardness @ day 1 Hardness (d). day 5 Hardness @ day 7Example 1 55 93 96[EMIMJC1 No cure No cure No cureCured at room temperature for 5 days, baked at 80 °C for 30 min and cured at room temperature for tire rest of the timeHardness @ day 1 Hardness (a} day 5 Hardness @ day 7Example 1 50 54 86[EMIMJC1 No cure No cure No cure

[0146] Evaluation of exemplary blocked carbene catalysts with solvent based Michael addition resins

[0147] Table 5 summarizes a two-part solvent borne Michael addition formulation with exemplary blocked catalysts and controls. Part A was prepared by mixing the Michael donor resin (Acure 510-100), Michael accepter resin (Acure 550-105) and methylethylketone (MEK). Part Bs are the catalysts in ethanol. The ratio of the acrylate to the active H is 1 : 1. The catalyst was used at 3 mol% of the amount of acrylate. The part B was added to part A under stirring (150-200 rpm) for 2 min and the resulted formulas were applied right away. The pot-life was checked by recording the gel-time. The gel time is the length of time that the formula stops to flow in a vial.

[0148] Table 5Solvent borne Michael addition fonnula with exemplary cataly stsA B C D E FPart AAcure 510-100 24.80 g 24.80 g 24.80 g 24.80 g 24.80 gAcure 510-170 25.00 gAcure 550-105 13.94 g 13.94 g 13.94 g 13.94 g 13.94 g 13.94 gmethylethylketone 10.00 g 10.00 g 10.00 g 10.00 g 10.00 g 10.00 gPart BExample 1 0.62 gExample 3 1.44 gExample 16 11.27 g 11.27[EMIM]C1 0.53 gBlankEthanol 9.96 g 9.24 g 0.00 g 9.96 g 9.96 g 0.00 gAcure 510-170 is a malonate functional polyester resin with succinimide from AllnexAcaure 510-100 is a malonate functional polyester resin without succinimide from Allnex; 25.00 g was used due to the slight difference of equivalent weight between Acure 510-170 and Acure 510-100Acure 550-105 is an acid- free tetra-functional polyester acrylate from Allnex[EMIM]C1: l-ethyl-3-methylimidazol-3-ium chloride

[0149] The results summarized in Table 6 demonstrate that the inventive blocked catalysts showed curing and long gel-time while the parent compound didn’t cure the coatings.

[0150] Table 6Hardness @ day 1 Hardness @ day 7 Gel timeA 8 6 48 hrB 8 7 48 lirC 10 25 4-7 daysD No cure No cure n / aE No cure No cure n / aF 11 25 >7 days

[0151] PART D - ANTIMICROBIAL EXAMPLES

[0152] Catalyst antimicrobial studies:

[0153] Catalysts from Examples 2, 3, 4, 6, and 18 above were further evaluated for antimicrobial efficacy via the Kirby-Bauer Disk Diffusion Susceptibility test Protocol of ASM 2009 (incorporated herein by reference) using 1.4 pmol of a sample for each disc. The bacteria and fungi strains for this evaluation are listed in the following table:

[0154] The procedure for this evaluation was as follows: Samples were received in 20 mL glass vials. Twenty (20) ml of sterile de-ionized water was added to each vial and material was allowed to dissolve with mixing. The Kirby Bauer type disk diffusion testing was performed by aliquoting two hundred (200) pl of bacterial pool inoculum on each of 5 TSA plates (trypticase soy agar), spread out using an L spreader, then allowed to absorb into the agar until no liquid was visible on surface. Two 8 mm glass fdter disks were placed on plate and dosed with 10 pL of sample. Additionally, a 10 pL drop of material was placed directly on plates and allowed to absorb into agar before inverting and incubating at 30° C. The process was repeated using PDA plates and the Aspergillus niger / Penicillium citrinum pool used for ASTM D5590.Antimicrobial activity was determined by presence of clear inhibition zones around disks and / or drop of material after 24 hours of incubation. The testing results are summarized in the following table:

[0155] Anti-Microbial Efficacy

[0156] The data in the table above shows catalyst from Example 10 with a long alky chain had resistance to both bacteria and fungi and the other catalysts without a long alkyl chain do not necessarily show such resistance.

[0157] A further evaluation of latent carbene catalysts of the following structure and shown in the table below were evaluated using a similar procedure. All evaluated catalysts in this study had CIO or longer alkyl chains.As shown in the table below, catalysts of the above structure having a CIO or greater R2 group provided strong resistance to both bacteria and fungi strains.

[0158] Coating Films Anti-Microbial Studies:

[0159] Based on the above results, catalysts A, B, and E from the above table were further evaluated in coating films. Coating compositions of this study are provided in the following table:

[0160] Coating Compositions:*waterborne malonate and acrylate functional non-ionic polyurethane dispersion with Michael donor and acceptor groups commercially available from Allnex**blocked catalyst commercially available from Allnex for use in the Acure AQ systems.

[0161] To prepare the coating films, 6 mil wet drawdowns were made on CRS substrates, and the resulting coating were dried at room temperature for 7 days before being submitted for antimicrobial testing pursuant to a modified antimicrobial surface efficacy evaluation per JIS Z 2801. Antimicrobial activity was evaluated based on the Arch / Lonza version of JIS Z 2801 per the following: TSA (trypticase soy agar) media was used instead of Nutrient agar; spread plates, drop plates, and pour plates were used to evaluate bioburden recovery vs. pour plates alone; soil was not used in the inoculum as this is not needed to determine preservation of article itself (as precedent, mildew testing used to support mildew resistant claims under the Treated Article Exemption by ASTM D-3273 and ASTM D-5590 do not use soil in the inoculum); carrier size used was 25.4 mm x 25.4 mm of film alone; carriers were placed and inoculated on the interior lid of a sterile water collection vial which was then sealed after a glass cover slide was placedover inoculum; letheen broth was used as neutralizing recovery media vs SCDLP broth (both contain Lecithin and Polysorbate 80 as neutralizing agents)

[0162] The testing results are summarized below. All the samples using catalyst A, B, and E met the 2 log 10 reduction of both organisms to meet the antimicrobial activity requirements of the modified JI5 Z 2801 method as compared to the bare metal control.

[0163] Testing for Fungal Resistance:

[0164] Further evaluations of films prepared using catalysts A, B, and E for fungal resistance pursuant to ASTM D5590 were conducted as follows:(1) Preparation of Test Samples• The sample submitted was free film without any substrate material.• Duplicates were conducted for each sample against an Aspergillus niger pool (Table below).• Film was not leached due to concern of deforming free film.(2) Inoculation of Test Samples with Challenge Organisms• Fungal cultures were allowed to grow out on PDA until they sporulated (7 -10 days) then spores were harvested with 12 mL of sterile 0.1% Polysorbate 80.• Equal amounts of each spore suspension were mixed, then the population was adjusted to 1 x 106CFU / mL for in-use inoculum.• Painted filters were placed in the center of PDA plate.• Transferred 200 pL of the of the mixed fungal inoculum to a PDA agar plate.• The inoculum was spread evenly over the entire surface of the PDA agar plate using an L-shaped cell spreader.(3) Incubation of Plates• The inoculated plates were transferred to an incubator with a temperature setting to maintain 25 ± 2°C.• Plates were rated weekly for 4 weeks.• Samples passing both fungal pools with an average rating of 2 or less were considered protected.

[0165] The testing results are summarized in the following table. Results show that latent carbenes with long alky chains (e.g., CIO or longer) demonstrated resistance to the fungal pool.

[0166] Testing for Algal Resistance:

[0167] Further evaluations of films prepared using catalysts A, B, and E for algal resistance pursuant to ASTM D5589 were conducted as follows:(1) Preparation of Test Samples• Duplicate 1x1 inch square coupons were cut out from each sheet of coating.• A blank control of un-coated filter paper was used to confirm a valid test.(2) Inoculation of Test Samples with Challenge Organisms• Place 1x1 inch square coupons on solidified BG-11 agar plates.• Transferred 350 pL of the of the mixed algal inoculum to the substrate.• The inoculum was spread evenly over the entire surface of the substrate and agar plate, using an L-shaped cell spreader.• Allowed inoculum to absorb into the agar before incubation.(3) Incubation of Plates• The inoculated plates were transferred to the Percival Growth Chamber with a constant fluorescent light source at 50% intensity and a temperature setting to maintain 25 ± 2°C.• The testing was run on a 14-hour day light / 10-hour darkness cycle.• Humidity was maintained at 85%.

[0168] List of Standard algal strains used for the studies are provided in the table below.

[0169] The results are summarized in the following table and show the latent carbene catalysts having the long alkyl chains (e.g., CIO or greater) are resistance to algal strains.

[0170] Studies of Non-leachable anti -microbial latent catalyst:

[0171] Further studies were conducted on the anti-microbial efficacy of non-leachable antimicrobial latent catalysts herein. As discussed above, there are two exemplary strategies convert the latent carbene catalysts herein into non-leachable configurations. For instance, one approach is to convert the catalyst into a polymeric form, and another approach is to functionalize the catalyst with reactive groups. The latent carbene catalyst I below is an example of the latter, and shows catalyst from Example 18 further functionalized with a reactive hydroxyl group. With the hydroxy group, the catalyst below can be linked into a polyurethane network so the antimicrobial impact can be longer lasting.(Catalyst I)

[0172] The following table summarizes the testing results from a modified JIS Z 2801 (as discussed above) for antimicrobial surface efficacy with the films of waterborne Michael addition compositions and waterborne polyurethane coatings. For the polyurethane films, with addition of the above functionalized catalyst, the coating films evidenced better resistance than the a control without the catalyst. In the table below, Acure AQ is described above, A145 is a hydroxyfunctional polyacrylic dispersion commercially available from Covestro, and xD401 is an aliphatic polyisocyanate commercially available from Vencorex Chemicals.

[0173] A number of formulations have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the disclosure. Accordingly, other implementations are within the scope of the following claims. For example, the actions recited in the claims can be performed in a different order and still achieve desirable results.

[0174] It is noted that, as used in this specification and the appended claims, the singular forms a,” “an,” and “the,” include plural referents unless expressly and unequivocally limited to one referent. Thus, for example, reference to “an antioxidant” includes two or more differentantioxidants. As used herein, the term “include” and its grammatical variants are intended to be non-limiting, such that recitation of items in a list is not to the exclusion of other like items that can be substituted or added to the listed items.

[0175] For the purposes of this specification and appended claims, unless otherwise indicated, all numbers expressing quantities, percentages or proportions, and other numerical values used in the specification and claims, are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by the present disclosure. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

[0176] It is to be understood that each component, compound, substituent or parameter disclosed herein is to be interpreted as being disclosed for use alone or in combination with one or more of each and every other component, compound, substituent or parameter disclosed herein.

[0177] It is further understood that each range disclosed herein is to be interpreted as a disclosure of each specific value within the disclosed range that has the same number of significant digits. Thus, for example, a range from 1 to 4 is to be interpreted as an express disclosure of the values 1, 2, 3 and 4 as well as any range of such values.

[0178] It is further understood that each lower limit of each range disclosed herein is to be interpreted as disclosed in combination with each upper limit of each range and each specific value within each range disclosed herein for the same component, compounds, substituent or parameter. Thus, this disclosure to be interpreted as a disclosure of all ranges derived by combining each lower limit of each range with each upper limit of each range or with each specific value within each range, or by combining each upper limit of each range with each specific value within each range. That is, it is also further understood that any range between the endpoint values within the broad range is also discussed herein. Thus, a range from 1 to 4 also means a range from 1 to 3, 1 to 2, 2 to 4, 2 to 3, and so forth.

[0179] Furthermore, specific amounts / values of a component, compound, substituent or parameter disclosed in the description or an example is to be interpreted as a disclosure of eithera lower or an upper limit of a range and thus can be combined with any other lower or upper limit of a range or specific amount / value for the same component, compound, substituent or parameter disclosed elsewhere in the application to form a range for that component, compound, substituent or parameter.

[0180] While particular embodiments have been described, alternatives, modifications, variations, improvements, and substantial equivalents that are or can be presently unforeseen can arise to applicants or others skilled in the art. Accordingly, the appended claims as filed and as they can be amended are intended to embrace all such alternatives, modifications variations, improvements, and substantial equivalents.

Claims

CLAIMSWHAT IS CLAIMED IS:

1. A latent catalyst for use in two-component crosslinkable coating systems, the latent catalyst comprising: a salt having a structure of BR+A' (Formula I); wherein the BR+cation thereof has a structure configured to be deprotonated forming a carbene or an olefin with the B moiety thereof including a 5-, 6-, or 7-membered heterocycle including two or more heteroatoms with an intermediate carbon atom and R moiety thereof being one or more substituents on the heterocycle selected from hydrogen or a substituted or unsubstituted alkyl group, vinyl group, aryl group, alkaryl group, hydrocarbyl group, or combinations thereof; and wherein the A’ anion is a carbonate anion, a bicarbonate anion, a carbamate anion, or combinations thereof.

2. The latent catalyst of claim 1, wherein R is a hydrocarbyl substituent with one or more carbon atoms thereof optionally replaced with a moiety selected from -O-, -S-, -C(O)-,-C(O)O-, -OC(O)O-, -S(O)-, -SO2-, -N(RX)-, -Si(-Rx)(Ry)-, or combinations thereof, wherein Rxand Ryare each, independently, selected from hydrogen, a hydrocarbyl group, or a substituted hydrocarbyl group.

3. The latent catalyst of claim 1 or 2, wherein the BR cation is a 1,3-di-substituted imidazolium compound, tautomer thereof, or derivative thereof.

4. The latent catalyst of any preceding claim, wherein the 5-, 6-, or 7-membered aromatic heterocycle of the BR+cation includes a fused bi-cyclic compound, a bis-heterocyclic compound, or combinations thereof.

5. The latent catalyst of any preceding claim, wherein the two or more heteroatoms are nitrogen atoms and wherein the intermediate carbon atom is configured to form the carbene.

6. The latent catalyst of any preceding claim, wherein the BR+cation has the structure of Formula II or tautomer thereof:(Formula II) wherein each of Ri, R2, R3, and R4 is, independently, hydrogen or a substituted or unsubstituted alkyl, vinyl, aryl, or alkaryl group and R’ is hydrogen or a -CHR5R6 group, while either Rs or Re is independently hydrogen, a substituted or unsubstituted alkyl, aryl, or alkaryl group, in some occasions, Rs and Re can form a ring or Rs or Re, independently forms a ring with either Ri or R2.

7. The latent catalyst of claim 6, wherein Ri and R4, along with the atoms to which they are attached, combine to form a substituted or unsubstituted aliphatic, aromatic, or heterocyclic ring structure.

8. The latent catalyst of claim 6 or claim 7, wherein R2 and R3, along with the atoms to which they are attached, combine to form a substituted or unsubstituted aliphatic, aromatic, or heterocyclic ring structure.

9. The latent catalyst of claims 6 to 8, wherein R3 and R4, along with the atoms to which they are attached, combine to form a substituted or unsubstituted aliphatic, aromatic, or heterocyclic ring structure.

10. The latent catalyst of claim 6, wherein at least one of Ri, R2, R3, and R4 is a Cl to C25 saturated or unsaturated alkyl group.

11. The latent catalyst of claim 6, wherein at least one of Ri, R2, R3, and R4 includes a substituted or unsubstituted aromatic moiety having 6 to 18 carbon atoms selected from a phenyl, a naphthyl, a phenanthryl, an anthracyl, a biphenyl, or a terphenyl group.

12. The latent catalyst of any preceding claim, wherein the BR+cation has the structure of Formula Ila or tautomer thereof:(Formula Ila) wherein each of Ri, R2, R3, and R4 is, independently, hydrogen or a substituted or unsubstituted alkyl, vinyl, aryl, or alkaryl group, each R’ is, independently, hydrogen or a -CHR5R6 group, while either Rs or Re is independently hydrogen, a substituted or unsubstituted alkyl, aryl, or alkaryl group, in some occasions, Rs and Re can form a ring or Rs or Re, independently forms a ring with either Ri or R2, and R is a hydrocarbyl group with one or more carbon atoms thereof optionally replaced with a moiety selected from -O-, -S-, -C(O)-, -C(O)O-, -OC(O)O-, -S(O)-, -SO2-, -N(RX)-, -Si(-Rx)(Ry)-, or combinations thereof, wherein Rx and Ryare each independently selected from hydrogen, a hydrocarbyl group, or a substituted hydrocarbyl group.

13. The latent catalyst of claim 12, wherein Ri and R4, along with the atoms to which they are attached, combine to form a substituted or unsubstituted aliphatic, aromatic, or heterocyclic ring structure.

14. The latent catalyst of claim 12 or claim 13, wherein R2 and R3, along with the atoms to which they are attached, combine to form a substituted or unsubstituted aliphatic, aromatic, or heterocyclic ring structure.

15. The latent catalyst of claims 12 to 14, wherein R3 and R4, along with the atoms to which they are attached, combine to form a substituted or unsubstituted aliphatic, aromatic, or heterocyclic ring structure.

16. The latent catalyst of claim 1, wherein BR+A’ is 1,3-dialkyl imidazolium bicarbonate or carbonate salt.

17. The latent catalyst of any one of claims 1 to 16, wherein the A' anion has the structure of Formula III(Formula III) wherein Rs is hydrogen, alkyl, aryl, alkaryl, hydrocarbyl, or combinations thereof.

18. The latent catalyst of claim 17, wherein Rs is a hydrocarbyl group and wherein, optionally, one or more carbon atoms thereof is replaced with a moiety selected from -O-, -S-, -C(O)-, -C(O)O-, -OC(O)O-, -S(O)-, -SO2-, -N(Rx)-, -Si(-Rx)(Ry)-, or combinations thereof, wherein Rxand Ry are each independently selected from hydrogen, a hydrocarbyl group, or a substituted hydrocarbyl group.

19. The latent catalyst of any one of claims 1 to 16, wherein the A’ anion has the structure of Formula IV(Formula IV) wherein Re and R? are each, independently, hydrogen or linear or branched alkyl, aryl, alkaryl, hydrocarbyl, or combinations thereof.

20. The latent catalyst of claim 19, wherein one or both of Re and R? is, independently, a hydrocarbyl group and wherein, optionally, one or more carbon atoms thereof is replaced with a moiety selected from -O-, -S-, -C(O)-, -C(O)O-, -OC(O)O-, -S(O)-, -SO2-, -N(Rx)-, -Si(-Rx)(Ry)-, or combinations thereof, wherein Rx and Ry are each independently selected from hydrogen, a hydrocarbyl group, or a substituted hydrocarbyl group.

21. The latent catalyst of claim 19, wherein Re and R7 including the nitrogen atom to which they are attached combine to form a ring structure.

22. The latent catalyst of claim 21, wherein the ring structure is a heterocyclic ring structure23. The latent catalyst of claim 22, wherein the heterocyclic ring structure is a succinimide ring structure.

24. A crosslinkable two-component waterborne or solvent borne coating composition comprising: a water-based or an organic solvent-based carrier fluid; a first ingredient or portion thereof having at least two protons that can be activated to form a Michael carbanion donor; a second ingredient or portion thereof having at least two ethylenically unsaturated functionalities each activated by an electron-withdrawing group to form a Michael acceptor; and the latent catalyst of any one of claims 1 to 23.

25. The crosslinkable two-component waterborne or solvent borne coating composition of claim 24, wherein the coating composition further includes pigments, matting agents, fillers, wetting agents, defoamers, rheological modifiers, ultraviolet (UV) light stabilizers, dispersing agents, flow and leveling agents, optical brighteners, gloss additives, radical inhibitors, radical initiators, adhesion promotors, plasticizers, waxes, or combinations thereof.

26. The crosslinkable two-component waterborne or solvent borne coating composition of claim 24 or 25, wherein the composition includes about 0.01 to about 20 weight percent of the latent catalyst.

27. The crosslinkable two-component waterborne or solvent borne coating composition of any one of claims 24 to 26, wherein the composition includes a weight ratio of the Michael carbanion donor to the Michael acceptor of about 1 :3 to about 3:1, preferably about 1 :2 to about 2: 1, and more preferably about 1 : 1.5 to about 1.5: 1.

28. The crosslinkable two-component waterborne or solvent borne coating composition of any one of claims 24 to 27, wherein the carrier fluid includes about 5 to 100 weight percent water based on the total weight of the carrier fluid.

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