Curable coating compositions and coated articles

Abstract

This invention provides a Michael addition-curable composition comprising A) at least one reactive donor capable of providing two or more nucleophilic carbanions; B) at least one reactive acceptor comprising two or more carbon-carbon double bonds; and C) at least one catalyst for catalyzing a Michael addition crosslinking reaction between the at least one reactive donor and the at least one reactive acceptor. This specification also provides coating compositions comprising the composition and coated articles made therefrom.

Description

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 62 / 705,210, filed June 16, 2020, and U.S. Provisional Patent Application No. 63 / 159,739, filed March 11, 2021, the entire contents of which are incorporated herein by reference. Background Technology

[0002] Coatings are frequently applied to a variety of substrates, including wood, metal, plastic, ceramic, cement board, and others, to provide surface protection and / or prevent corrosion. These coatings are typically multi-layered and are economical and relatively easy to apply. The coatings dry quickly and have good corrosion and chemical resistance, making them particularly suitable for coating components intended for long-term use and / or in corrosive environments.

[0003] Conventionally, these coatings are applied to a substrate surface to provide surface and / or corrosion protection, and typically include epoxy resins, polyurethane resins, and combinations thereof. Typically, such coating systems are crosslinkable two-component compositions, where the components are stored separately and mixed prior to use.

[0004] Two-component polyurethane systems are common in industry and typically include isocyanate-functionalized compounds. However, the human health risks and environmental problems associated with isocyanate-functionalized compounds are receiving increasing attention. Free isocyanates are considered a serious human health hazard, and there is growing regulatory pressure to significantly reduce or eliminate the use of isocyanate-functionalized compounds in coatings. Therefore, non-isocyanate curing (NISO or NICN) curing systems have generated significant interest in the field of coating technology.

[0005] One potentially interesting NICN system is the Michael addition (MA) curing system. This system offers several advantages over conventional isocyanate-based curing systems, including curing at lower temperatures, longer pot life, and compatibility with high-solids, low-volatile organic compound (VOC) systems. These MA systems typically include a catalyst to increase the rate of crosslinking between the two components. Alkali-catalyzed systems are preferred because they can cure rapidly or quickly. However, due to the rapid curing rate, these compositions are only usable after the components are mixed and for a relatively short period, defined as the pot life of the coating composition. In some alkali-catalyzed systems, the viscosity increases so rapidly that the coating cures before it can be fully applied to the surface, and therefore, these systems have limited practical applications. The problem of shortened pot life in MA systems has been solved by using potential base catalysts for single-coat systems, as described in U.S. Patent Nos. 8,962,725, 9,181,452, 9,181,453, 9,260,626, 9,284,423, 9,534,081, 9,587,1389,834,701, 10,017,607 and related applications.

[0006] However, the MA curing systems described in these patents have some significant drawbacks. For example, when cured at room temperature (in the range of 20°C to 27°C), the system results in a much lower film hardness compared to conventional two-component polyurethane systems. Furthermore, the MA curing systems described in these patents are known not to provide optimal adhesion and / or sufficient corrosion resistance when applied directly to certain substrates.

[0007] Therefore, there is a need for improved MA curing systems that offer the advantages of improved curing and increased pot life, while also exhibiting optimal adhesion, film hardness, and other important coating performance characteristics. Summary of the Invention

[0008] This specification provides compositions and methods involving Michael addition (MA) reactions. The compositions described herein are MA-curable compositions and exhibit optimal curing properties and pot life. Coatings derived from the MA-curable compositions described herein exhibit optimal mechanical and property properties upon application to and curing of a substrate.

[0009] In one aspect, the present invention provides a Michael addition (MA) curable composition comprising:

[0010] A) It can provide at least one reactive donor for two or more nucleophilic carbanions;

[0011] B) At least one reactive acceptor containing two or more carbon-carbon double bonds; and

[0012] C) A catalyst for catalyzing a Michael addition crosslinking reaction between at least one reactive donor and at least one reactive acceptor.

[0013] The catalyst contains at least one quaternary salt having the following structural formula I.

[0014] R 1 R 2 R 3 R 4 M + X - (Formula I)

[0015] In this formula,

[0016] ■R 1 R 2 R 3 and R 4 Each is independently selected from C1-C12 alkyl, C6-C14 aryl, C7-C15 alkylaryl, C7-C15 aralkyl, and any combination thereof, or R 1 R 2 R 3 and R 4 Any two of them, together with the M atoms to which they are attached, form a heterocycle;

[0017] ■M is N or P, preferably N, and

[0018] ■X - Derived from at least one acid, at least one acid anhydride, or a combination thereof, having a pKa value in the range of 0 to 10, preferably in the range of 1 to 8, wherein the pKa value is measured at 25°C in an aqueous solution of at least one acid, at least one acid anhydride, or a combination thereof, and wherein X - It is not an acid or anhydride derived from carbonic acid or carbamic acid.

[0019] In some embodiments, the MA-curable compositions described herein provide a pot life of at least 2 hours at 25°C after mixing the components of the composition.

[0020] In one embodiment, the MA-curable composition described herein can be cured at room temperature (in the range of 20°C to 27°C) or higher and in a time of 7 days or less.

[0021] In some embodiments, the MA-curable compositions described herein can be used to manufacture coatings, adhesives, sealants, foams, films, molded products, or inks.

[0022] In another aspect, this specification provides a coated article comprising a substrate having at least one main surface; and a cured coating formed by the MA coating composition described herein, the cured coating being applied directly or indirectly, at least partially, to the main surface. Preferably, the substrate comprises wood, metal, plastic, ceramic, cement board, or any combination thereof.

[0023] The above overview of the content described herein is not intended to describe every disclosed embodiment or every implementation. The following description illustrates exemplary embodiments in more detail. Guidance is provided in several places throughout this application by listing examples that can be used in various combinations. In each case, the cited list is used only as a representative group and should not be construed as an exclusive enumeration.

[0024] Details of one or more embodiments described herein are set forth in the accompanying drawings and the description below. Other features, objectives, and advantages will become apparent from the specification, drawings, and claims.

[0025] Selected definition

[0026] As used herein, the terms “an,” “a,” “the,” “at least one,” and “one or more” are used interchangeably. Thus, for example, a coating composition containing “an” additive may be interpreted as meaning that the coating composition contains “one or more” additives.

[0027] The term "component" refers to any compound that contains specific features or structures. Examples of components include compounds, monomers, oligomers, polymers, and the organic groups contained therein.

[0028] 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.). As used herein in the context of at least one reactive acceptor, the term refers to a structure containing a carbon-carbon double bond but excluding an aromatic ring. The term "alkene-type unsaturation" is used interchangeably with "double bond" herein.

[0029] As used herein, the term "Michael addition" refers to the nucleophilic addition of a carbanion provided by at least one reactive donor to an electrophilic conjugated system (such as a carbon-carbon double bond of at least one reactive acceptor). The Michael addition reaction follows the general reaction diagram shown herein:

[0030]

[0031] In the reaction diagram shown above, at least one of the substituents R and R' on the reactive donor is an electron-withdrawing group, such as an acyl group, a ketyl group, or a cyano group, such that the hydrogen on the methylene group of at least one reactive donor can be deprotonated and form a carbanion in the presence of catalyst B, and at least one reactive acceptor typically includes α, β-unsaturated ketones, aldehydes, carboxylic acids, esters, nitriles, nitro groups, and other compounds.

[0032] As used herein, the term "quaternary salt" refers to a quaternary ammonium salt and / or a quaternary phosphorus salt having an anionic group. In one embodiment, the quaternary salt is a quaternary ammonium salt. As an example, a quaternary ammonium salt can be formed by reacting a tertiary amine having a lone pair of electrons with an acid having hydrogen ions, or by reacting a quaternary ammonium base with an acid having hydrogen ions.

[0033] As used herein, the term "pKa" refers to the negative logarithmic value of the dissociation constant (Ka) of an acid or anhydride in an aqueous solution. A smaller pKa value indicates that hydrogen ions dissociate more readily from the acid or anhydride, and that the acidity of the acid or anhydride is stronger. In this specification, the pKa value is obtained by measuring the dissociation constant of the acid or anhydride in an aqueous solution at 25°C and taking the negative logarithmic value of the measured dissociation constant. When using anhydrides, the pKa value refers to the pKa value of the acid formed by the anhydride in an aqueous solution. In cases where multiple dissociations of the acid or anhydride occur in an aqueous solution, the pKa of the acid or anhydride is determined based on the first-order dissociation constant (Ka1).

[0034] As used herein, the term "epoxy-functional component" refers to a component having at least one epoxy functional group. In the MA-curable compositions described herein, the epoxy-functional component may be a reactive donor, a reactive acceptor, or another component. As an example, the epoxy functional group of the epoxy-functional component may be derived from glycidyl ethers, glycidyl esters, epoxy-functionalized alkanes, epichlorohydrins, epoxy resins, etc.

[0035] When used herein, as the name suggests, the term "metal oxide" refers to a binary compound formed by a metal element and an oxygen element, and that the binary compound is capable of dissociating metal ions. Similarly, the term "metal salt" refers to a compound formed by bonding one or more metal ions and an anion through ionic bonds, and that the compound is capable of dissociating metal ions.

[0036] In the context of "metal oxides or metal salts," the term "pH" refers to a parameter used to measure the acidity and alkalinity of metal oxides or metal salts. This is tested by uniformly dispersing 5 grams of the metal oxide or salt in 100 g of an aqueous medium (e.g., deionized water with a pH of 7.0) to form an aqueous dispersion, and then measuring the pH of the resulting aqueous dispersion several times using a BPH-220 pH meter, and taking the average value. In some embodiments described herein, the metal oxide or metal salt is weakly alkaline and has a pH in the range of 8-12.

[0037] As used herein, the term "curing" refers to the process in which the composition undergoes a cross-linking chemical reaction, thereby changing from a liquid, fluid, or gel state to a solid state. When referring to "Michael addition-curing compositions," the term "curing time" refers to the time required for the mixture to polymerize and cure and exhibit effective end-use properties.

[0038] When referring to a “Michael addition-curing composition,” the term “detack time” means the time required for the resulting coating to become non-sticky to the touch, for example, after mixing the components of the composition at a specific temperature to form a mixture and applying the mixture to a test substrate at a specific wet coating thickness (e.g., 100 μm). In some embodiments, detack time can also be tested by other methods known in the art.

[0039] When referring to a "Michael addition-curing composition," the term "gel time" refers to the time required for the resulting mixture obtained by mixing the components of the composition at a specific temperature to reach a non-flowing gel state. In the embodiments described herein, gel time is a parameter used to measure the curing activity of the Michael addition-curing system.

[0040] As used herein, the term "ambient temperature" refers to the ambient temperature in a typical indoor environment, typically ranging from 15°C to 40°C, and preferably from 20°C to 27°C. The term "room temperature" is used interchangeably with "ambient temperature" herein.

[0041] As used herein, the term "fit time" refers to the period of time following the mixing of the components of a Michael addition-curing composition or coating composition. Specifically, it refers to the time required for the viscosity of the mixed components to double its initial viscosity. This term is used interchangeably with "gel time" herein.

[0042] In the context of reactive donors, the term "nucleophilic carbanion" refers to a reactive intermediate of carbon with a lone pair of electrons attached to it by two or three strongly electronegative groups. Strongly electronegative groups may include, but are not limited to, -NO2, -C(=O)-, -CO2R1, -SO2-, -CHO, -CN, and -CONR2, where R1 and R2 each independently represent an alkyl group. In some embodiments described herein, the nucleophilic carbanion is derived from the acidic proton CH in an activated methylene group, a methine group, or a combination thereof.

[0043] When used in the context of a substrate, the term "main surface" refers to the surface formed by the longitudinal and transverse dimensions of the substrate for providing decoration.

[0044] When used in the context of a coating composition applied to the main surface of a substrate, the term "on" includes coating compositions applied directly or indirectly to the main surface of the substrate. In some embodiments, the coating composition described herein is applied directly to the main surface of the substrate to form a coating. In other embodiments, one or more barrier layers or adhesion-promoting layers may be present between the coating composition described herein and the substrate.

[0045] The term "volatile organic compounds" ("VOCs") refers to any compound of carbon that participates in atmospheric photochemical reactions, excluding carbon monoxide, carbon dioxide, carbonic acid, metal carbides or carbonates, and ammonium carbonate. Typically, VOCs have a vapor pressure equal to or greater than 0.1 mm Hg. As used herein, "volatile organic compound content" ("VOC content") refers to the weight of VOCs per volume of the composition or coating composition and is reported, for example, in kilograms (kg) per liter of VOC, as measured by ISO 11890-1:2007.

[0046] The terms “comprising,” “including,” “containing,” and their variations, when used in the specification and claims, do not have a limiting meaning.

[0047] The terms "preferred" and "ideally" refer to embodiments described herein that provide certain beneficial effects in certain circumstances. However, other embodiments may also be preferred in the same or other circumstances. Furthermore, the description of one or more preferred embodiments does not imply that other embodiments are unavailable, and is not intended to exclude other embodiments from the scope described herein.

[0048] Furthermore, in this document, the numerical range expressed by endpoints includes all numerical values ​​contained within that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, 5, etc.). In addition, disclosure of a range includes disclosure of all subranges included in a wider range (e.g., 1 to 5 discloses 1 to 4, 1.5 to 4.5, 1 to 2, etc.). Detailed Implementation

[0049] This specification provides methods and compositions for application to a variety of substrates, including wood, plastics, metals, ceramics, cement boards, and other substrates. Specifically, this specification provides coating compositions or systems derived from components that cure via a Michael addition reaction (i.e., Michael addition (MA) curable compositions or systems).

[0050] In embodiments, this specification provides a Michael addition-curable system or composition. The composition comprises A) at least one reactive donor capable of providing two or more nucleophilic carbanions; B) at least one reactive acceptor containing two or more carbon-carbon double bonds; and C) a catalyst for catalyzing a Michael addition crosslinking reaction between at least one reactive donor and at least one reactive acceptor.

[0051] The catalyst is at least one quaternary salt having the structure of a compound of formula I.

[0052] R 1 R 2 R 3 R 4 M + X - (Formula I)

[0053] in

[0054] ■R 1 R 2 R 3 and R 4 Each is independently selected from C1-C12 alkyl, C6-C14 aryl, C7-C15 alkylaryl, C7-C15 aralkyl, and any combination thereof, or R 1 R 2 R 3 and R 4 Any two of them, together with the M atoms to which they are attached, form a heterocycle;

[0055] ■M is N or P, preferably N; and

[0056] ■X -Derived from at least one acid, at least one acid anhydride, or a combination thereof, having a pKa value in the range of 0 to 10, preferably in the range of 1 to 8, wherein the pKa value is obtained by measurement at 25°C in an aqueous solution of at least one acid, at least one acid anhydride, or a combination thereof, and wherein X - It is not an acid or anhydride derived from carbonic acid or carbamic acid.

[0057] In some embodiments, this specification provides Michael addition-curable compositions. In one aspect, the composition includes at least one reactive donor capable of providing two or more nucleophilic carbanions. A nucleophilic carbanion is an active intermediate of carbon having a lone pair of electrons, to which two or three strongly electronegative groups are typically attached. Suitable examples of such strongly electronegative groups include, but are not limited to, -NO2, -C(=O)-, -CO2R1, -SO2-, -CHO, -CN, and -CONR2, wherein R1 and R2 each independently represent an unsubstituted alkyl group, a substituted alkyl group, an unsubstituted aryl group, a substituted aryl group, a substituted and unsubstituted aralkyl group, etc.

[0058] At least one reactive carbophile carbanion is derived from an acidic proton CH in an activated methylene group, a methine group, or a combination thereof. In another embodiment, at least one reactive carbophile carbanion is derived from two or more acidic protons CH in an activated methylene group, a methine group, or a combination thereof. Suitable examples of substances capable of providing acidic protons CH include, but are not limited to, dialkyl malonates (e.g., dimethyl malonate, diethyl malonate, etc.), cyanoacetates (e.g., methyl cyanoacetate, ethyl cyanoacetate, etc.), acetoacetates, propionyl acetates, acetylacetone, dipropionylmethane, etc., and mixtures or combinations thereof.

[0059] The glass transition temperature of at least one reactive donor is not particularly limited and will vary depending on the desired end use and performance characteristics of the coating composition described herein. For example, in cases where a cured coating with optimal hardness is required, it may be advantageous to increase the glass transition temperature (Tg) of at least one reactive donor to at least 0°C. However, in this exemplary case, the Tg of at least one reactive donor should not be much higher than 40°C to avoid any negative impact on curing.

[0060] In some embodiments, at least one reactive donor can be obtained by reacting a compound, oligomer, or polymer that is functionalized to serve as the reactive donor backbone with an acetoacetate or malonate compound.

[0061] In some embodiments, at least one reactive donor may include a reactive donor having a backbone based on polyester resin, acrylic resin, polyurethane resin, epoxy resin, or a combination thereof.

[0062] Where at least one reactive donor has a polyester backbone, a suitable polyester resin that can be functionalized to act as a reactive donor can be obtained by esterifying an acid component containing a dicarboxylic acid or polycarboxylic acid or their anhydrides with one or more diols or polyols. Suitable examples of dicarboxylic acids or polycarboxylic acids include, but are not limited to, aliphatic dicarboxylic acids such as malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, octanoic acid, azelaic acid, sebacic acid, anhydrides of these acids, and mixtures or combinations thereof; alicyclic dicarboxylic acids and / or anhydrides such as 1,3- / 1,4-cyclohexanedicarboxylic acid, dicyclohexanemethane-4,4'-dicarboxylic acid, and aromatic dicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid, trimellitic anhydride, anhydrides of these acids, and mixtures or combinations thereof. Preferred examples of diols or polyols include, but are not limited to, trimethylolpropane, pentaerythritol, neopentyl glycol, diethylene glycol, 1,4-butanediol, ethylhexylpropanediol, 2,4-diethyl-1,5-pentanediol, bis(trimethylolpropane), dipentaerythritol, or any combination thereof.

[0063] Polyester resins can be functionalized, for example, by reaction with diene, transesterification with alkyl acetoacetate or dialkyl malonate, or esterification with malonic acid, monoester, or acid-functionalized malonic acid esters. In one aspect, at least one reactive donor is obtained by transesterification of a polyester resin with an alkyl acetoacetate or dialkyl malonate, wherein the malonic acid ester or acetoacetate functional group is present in the main chain as a terminal group or end group, or both, preferably as a terminal group or end group. In another aspect, at least one reactive donor is obtained by direct transesterification of a diol or polyol with an alkyl acetoacetate or dialkyl malonate, wherein the malonic acid ester or acetoacetate functional group is preferably present as a terminal group or end group.

[0064] In an embodiment, where at least one reactive donor has an acrylic resin-based backbone, a suitable acrylic resin that can be functionalized to act as a reactive donor can be obtained by copolymerizing an acrylic monomer comprising (meth)acrylic acid, (meth)acrylic acid hydroxyalkyl ester, or any combination thereof with one or more other olefinically unsaturated monomers. Other olefinically unsaturated monomers include, but are not limited to, styrene, such as styrene, vinyltoluene, o-methylstyrene, p-methylstyrene, α-butylstyrene, 4-n-butylstyrene, 4-n-decylstyrene, halostyrene (such as monochlorostyrene, dichlorostyrene, tribromostyrene, or tetrabromostyrene); C1-20 alkyl esters of (meth)acrylate, examples of which include, but are not limited to, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, 2-methyloctyl (meth)acrylate, 2-tert-butylheptyl (meth)acrylate, 3-isopropylheptyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate. 5-methylundecyl methacrylate, 2-methyldodecyl methacrylate, tridecyl methacrylate, 5-methyltetrazyl methacrylate, tetradecyl methacrylate, pentadecyl methacrylate, hexadecyl methacrylate, 2-methylhexadecyl methacrylate, heptadecanyl methacrylate, 5-isopropylheptadecanyl methacrylate, 5-ethyloctadecyl methacrylate, octadecyl methacrylate, nonadecanyl methacrylate, eicosyl methacrylate, cycloalkyl methacrylate (e.g., cyclopentyl methacrylate, cyclohexyl methacrylate, 3-vinyl-2-butylcyclohexyl methacrylate, cycloheptyl methacrylate, cyclooctyl methacrylate), norbornyl methacrylate, and isonorbornyl methacrylate; or any combination thereof. Other acrylic monomers preferably include styrene, methylstyrene, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, or any combination thereof. Acrylic resins can be functionalized, for example, by reaction with diene, by ester exchange with alkyl acetoacetate or dialkyl malonate, by esterification with malonic acid or monoester or acid-functionalized malonic acid esters, etc.In a preferred embodiment, at least one reactive donor is obtained by transesterification of an acrylic resin with an alkyl acetoacetate or a dialkyl malonate, wherein the malonate or acetoacetate functional group is present as a side chain in the main chain, or as both, preferably as a side chain. In another preferred embodiment, the acrylic donor can be prepared by polymerizing an activated methylene-functionalized (meth)acrylic acid monomer with or without any combination of the above-described olefinically unsaturated monomers. Suitable activated methylene-functionalized (meth)acrylic acid monomers include, for example, acetoacetoxyethyl methacrylate.

[0065] In an embodiment, at least one reactive donor has a polyurethane-based backbone. Exemplary polyurethane resins that can be functionalized to act as reactive donors can be obtained by condensing a hydrogen-containing polymer with one or more polyisocyanates. As used herein, the term "hydrogen-containing polymer" refers to any polymer that inherently contains functional groups capable of providing active hydrogen and / or any polymer that contains functional groups capable of being converted into active hydrogen during the preparation and / or application of the reactive donor. Suitable examples include, but are not limited to, one or more of vinyl acetate-ethylene copolymers, vinyl acetate-ethylene-(meth)acrylate copolymers, vinyl acetate-(meth)acrylate copolymers, polyvinyl acetate, polyvinyl alcohol, acrylic polymers or copolymers, polyesters, polyethers, or any combination thereof. Examples of polyisocyanates include, but are not limited to, hexamethylene diisocyanate, dodecyl diisocyanate, cyclohexane-1,4-diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, cyclopentane-1,3-diisocyanate, benzene-1,4-diisocyanate, toluene-2,4-diisocyanate, naphthalene-1,4-diisocyanate, biphenyl-4,4'-diisocyanate, benzene-1,2,4-triisocyanate, xylene-1,4-diisocyanate, xylene-1,3-diisocyanate, diphenylmethane diisocyanate, butane-1,2,3-triisocyanate, or polymethylene polyphenyl polyisocyanate, or their polyurethane prepolymers, their polyester prepolymers, or their polyether prepolymers, and any combination thereof. Polyurethane resins can be functionalized, for example, by reaction with diene, transesterification with alkyl acetoacetate or dialkyl malonate, or esterification with malonic acid, monoester, or acid-functionalized malonic acid ester polyesters. In a preferred embodiment, at least one reactive donor is obtained by transesterification of the polyurethane resin with alkyl acetoacetate or dialkyl malonate, wherein the malonic acid ester or acetoacetate functional group is present in the main chain as a terminal group or end group, or both, preferably as a terminal group or end group.

[0066] In embodiments, at least one reactive donor has an epoxy resin-based backbone. Exemplary epoxy resins that can be functionalized to act as reactive donors include, but are not limited to, bisphenol A epoxy resin, bisphenol F epoxy resin, and phenolic varnish epoxy resin, as well as mixtures or combinations thereof. Epoxy resins can be functionalized, for example, by reacting with diene, by transesterification with alkyl acetoacetate or dialkyl malonate, by esterification with malonic acid or monoester or acid-functionalized malonic acid ester polyester, etc. In a preferred embodiment, at least one reactive donor is obtained by transesterification of an epoxy resin with alkyl acetoacetate or dialkyl malonate, wherein the malonic acid ester or acetoacetate functional group is present in the backbone as a terminal group or end group, or both, preferably as a terminal group or end group.

[0067] In another embodiment, at least one reactive donor may comprise at least one reactive diluent obtained from a diol or polyol via transesterification. Suitable examples of diols or polyols include, but are not limited to, trimethylolpropane, pentaerythritol, neopentyl glycol, diethylene glycol, 1,4-butanediol, ethylhexylpropanediol, 2,4-diethyl-1,5-pentanediol, bis(trimethylolpropane), dipentaerythritol, or any mixture or combination thereof. In many embodiments, at least one reactive donor comprises at least one reactive diluent obtained from at least one diol or at least one polyol via transesterification. In a preferred embodiment, at least one reactive diluent is obtained by transesterification of a diol or polyol with an alkyl acetoacetate or a dialkyl malonate.

[0068] In some embodiments, at least one reactive donor may comprise a raw material of the at least one reactive diluent described above, such as a diol or polyol and an alkyl acetoacetate or a dialkyl malonate. Upon mixing with other components of the MA-curable composition, these raw materials of the at least one reactive diluent undergo transesterification.

[0069] Surprisingly, when at least one reactive donor comprises at least one reactive diluent obtained from a diol or polyol via transesterification, MA-curable compositions with high solids content and low viscosity can be successfully formulated. For example, MA-curable compositions can be formulated to have a solids content of 70% by weight or higher, preferably 80% by weight or higher, more preferably 90% by weight or higher, and a viscosity of 16 seconds or lower, wherein the viscosity is measured using an Iwata-2 cup at 25°C.

[0070] Therefore, the MA-curable compositions described herein can be directly applied during application, such as by direct spraying, without further dilution. This application process significantly reduces VOC emissions. In some embodiments, the MA-curable compositions containing reactive diluents have a VOC content of 400 g / L or less, preferably 200 g / L or less, as measured by ISO 11890-1:2007.

[0071] Without being limited by theory, it is believed that at least one reactive donor (including at least one reactive diluent with a low molecular weight) is beneficial for formulating the MA-curable compositions described herein with high solids content and low viscosity. Therefore, in one embodiment, the aforementioned reactive diluent has a weight-average molecular weight (Mw) of 1000 g / mol or less, preferably 800 g / mol or less, more preferably 500 g / mol or less.

[0072] In one embodiment, at least one reactive donor obtained from a diol or polyol via transesterification may contain three or more, preferably four or more, more preferably six or more, and even more preferably eight or more acidic protons (CH) in the activated methylene group, methine group, or a combination thereof. Without being theoretically limited, it should be noted that MA-curable compositions formulated with reactive donors having at least three acidic protons (CH) functional groups exhibit excellent film hardness. Surprisingly, MA-curable compositions formulated with reactive donors having six or more, or preferably eight or more acidic protons (CH) even exhibit low film shrinkage.

[0073] In some embodiments, the MA-curable compositions described herein include at least one reactive donor having a backbone based on a polyester, acrylic, polyurethane, epoxy resin, or a mixture or combination thereof, and at least one reactive diluent obtained from a diol or polyol via transesterification. In many embodiments, the at least one reactive donor includes at least one reactive diluent obtained from at least one diol or at least one polyol via transesterification.

[0074] There is no particular limitation on the amount of at least one reactive donor, and it can be determined by the desired end use and performance characteristics of the MA-curable composition described herein.

[0075] The MA-curable compositions or systems described herein include at least one reactive acceptor. The at least one reactive acceptor can be any organic compound that is electron-deficient and olefinically unsaturated (i.e., includes at least one carbon-carbon double bond). For example, a suitable reactive acceptor can be an α,β-unsaturated carbonyl compound having a carbonyl group or other electron-withdrawing group appearing at the α-position of the double bond. In embodiments, the at least one reactive acceptor described herein includes at least one carbon-carbon double bond. Preferably, the at least one reactive acceptor has two or more carbon-carbon double bonds. Generally, during the curing and crosslinking process of the compositions described herein, the higher the functionality of the acceptor, the higher the crosslinking density of the cured product, and the higher the hardness. Surprisingly, reactive acceptors containing two carbon-carbon double bonds are particularly advantageous for improving the hardness of cured coatings derived from the MA-curable systems described herein, compared to reactive acceptors containing more than two carbon-carbon double bond groups (e.g., reactive acceptors containing three or four carbon-carbon double bonds).

[0076] In the implementation scheme, at least one carbon-carbon double bond group of the reactive acceptor is a compound having a structure represented by Formula II:

[0077] C = C - CX (Equation II)

[0078] Wherein, CX represents any one of the following groups: alkenyl group, alkynyl group, aldehyde group, ketone group, ester group, and cyano group. Preferably, the carbon-carbon double bond group is derived from one or more of α,β-unsaturated aldehydes, α,β-unsaturated ketones, α,β-unsaturated carboxylic acid esters, and α,β-unsaturated nitriles, and is preferably an α,β-unsaturated carboxylic acid ester.

[0079] In one embodiment, at least one reactive receptor may be selected from one or more of the α,β-unsaturated carboxylic esters represented by the following formula:

[0080]

[0081]

[0082]

[0083]

[0084] as well as

[0085]

[0086] In a preferred embodiment, at least one reactive receptor may be selected from one or more of the α,β-unsaturated carboxylic acid esters represented by free formulas A, B and C, most preferably an α,β-unsaturated carboxylic acid ester represented by formula A.

[0087] In other embodiments, suitable examples of the reactive acceptors described herein include, but are not limited to, olefinic unsaturated acids and / or their esters, including, for example, fumaric acid, maleic acid, itaconic acid, etc., or esters of (meth)acrylic acid, i.e., (meth)acrylate functional compounds derived from the reaction of a hydroxyl-functional compound (i) with (meth)acrylic acid or its ester derivative (ii), wherein the hydroxyl-functional compound may be monofunctional, difunctional, or polyfunctional, and has the following as a backbone containing an aliphatic, alicyclic, or aromatic chain: (poly)epoxy resins, (poly)ethers, (poly)esters (e.g., (poly)caprolactone), (poly)alkyd resins, (poly)urethanes, (poly)amines, (poly)amides, (poly)carbonates, (poly)olefins, (poly)siloxanes, (poly)acrylates, halogens (e.g., fluorine), melamine derivatives, copolymers of any of them, etc., and mixtures and combinations thereof.

[0088] The amount of at least one reactive acceptor is not particularly limited and can be determined by the desired end use and performance characteristics of the MA-curable composition described herein. In some embodiments, the molar ratio of the nucleophilic carbanion of at least one reactive donor to the carbon-carbon double bond of at least one reactive acceptor may be in the range of 0.7:1 to 1.3:1, preferably 0.8:1 to 1.2:1, and more preferably 0.9:1 to 1.1:1.

[0089] In the MA-curable compositions described herein, in addition to at least one reactive donor and at least one reactive acceptor, the composition also comprises a resin that does not participate in the Michael addition reaction, including but not limited to polyester resins, acrylic resins, epoxy resins, polyurethane resins, and any combination thereof. The amount of these resins is not particularly limited and can be determined empirically.

[0090] The MA-curable compositions or systems described herein include a catalyst for catalyzing a Michael addition crosslinking reaction of at least one reactive acceptor and at least one reactive donor. In some embodiments, the Michael addition-curable compositions may further contain at least one additional catalyst. The presence of the catalyst ensures that the MA-curable compositions described herein maintain a suitable balance between pot life and curing rate, even at ambient temperature or room temperature.

[0091] In the embodiments, the catalyst comprises at least one quaternary salt having the structure of a compound of formula I.

[0092] R 1 R 2 R 3 R 4 M + X - (Formula I)

[0093] in

[0094] ■R 1 R 2 R 3 and R 4 Each is independently selected from C1-C12 alkyl, C6-C14 aryl, C7-C15 alkylaryl, C7-C15 aralkyl, and any combination thereof, or R 1 R 2 R 3 and R 4 Any two of them, together with the M atoms to which they are attached, form a heterocycle;

[0095] ■M is N or P, preferably N; and

[0096] ■X - Derived from at least one acid, at least one acid anhydride, or a combination thereof, having a pKa value in the range of 0 to 10, preferably in the range of 1 to 8, wherein the pKa value is measured at 25°C in an aqueous solution of at least one acid, at least one acid anhydride, or a combination thereof, and wherein X - It is not an acid or anhydride derived from carbonic acid or carbamic acid.

[0097] Surprisingly, and not limited to theory, it should be noted that the pKa value of an acid or anhydride is a significant factor affecting the catalytic activity of catalysts formed from the acids or anhydrides described herein. In embodiments, catalysts with a pKa less than 10 exhibit optimal catalytic activity. Preferably, the acids or anhydrides, and combinations thereof, have pKa values ​​in the range of 0 to 10, more preferably in the range of 1 to 8. As an example, the acids or anhydrides may have pKa values ​​in the range of 1 to 2, or in the range of 2 to 3, or in the range of 3 to 4, or in the range of 4 to 5, or in the range of 5 to 6, or in the range of 6 to 7, or in the range of 7 to 8, or in the range of 1.5 to 2.5, or in the range of 2.5 to 3.5, or in the range of 3.5 to 4.5, or in the range of 4.5 to 5.5, or in the range of 5.5 to 6.5, or in the range of 6.5 to 7.5, or in the range of 7.5 to 8.5, or any range consisting of any of these values ​​and any other values.

[0098] Suitable acids and / or anhydrides include, but are not limited to, one or more of aliphatic carboxylic acids, aromatic carboxylic acids, alicyclic carboxylic acids, inorganic weak acids, any of their anhydrides, and mixtures or combinations thereof. Preferably, the acids or anhydrides include, for example, formic acid, acetic acid, oxalic acid, glycolic acid, monohaloacetic acid, dihaloacetic acid, trihaloacetic acid, propionic acid, malonic acid, acrylic acid, lactic acid, propynic acid, glyceric acid, pyruvic acid, n-butyric acid, isobutyric acid, 3-butenoic acid, succinic acid, maleic acid, tartaric acid, n-valeric acid, isovaleric acid, pentenoic acid, glutamate, citraconic acid, mesoconic acid, glutamic acid, n-hexanoic acid, isohexanoic acid, hexenoic acid, citric acid, sebacic acid, ethylenediaminetetraacetic acid (EDTA), 1,2-cyclohexanedicarboxylic acid, gluconic acid, phthalic acid, trimellitic acid, pyromellitic acid, arsenic acid, hydrofluoric acid, hydrogen selenic acid, selenite, and their anhydrides.

[0099] In the MA-curable compositions described herein, tetraalkyl and trialkylaralkyl salts are preferably used as catalysts. Nitrogen-containing heterocyclic salts, such as those derived from pyridine, piperidine, piperazine, or morpholine, may also be used. Specific examples of cations include, but are not limited to, tetrabutylammonium cation, tetramethylammonium cation, tetraethylammonium cation, triethylbenzylammonium cation, tetrapropylammonium cation, tetrahexylammonium cation, tetraoctylammonium cation, tetradecylammonium cation, tetraacetylammonium cation, triethylhexylammonium cation, 2-hydroxyethyltrimethylammonium cation, methyltrioctylammonium cation, hexadecyltrimethylammonium cation, and 2-chloroethyltrimethylammonium cation.

[0100] The amount of catalyst used herein is not particularly limited and can be varied depending on the properties and end use of the MA-curable composition described herein. Preferably, the amount of catalyst present is at least 1.0% by weight, preferably at least 1.4% by weight, but preferably not more than 5% by weight, based on the amount of catalyst relative to the total solids of the MA-curable composition. In some embodiments, the Michael addition-curable composition may also contain at least one additional catalyst.

[0101] In another embodiment, the Michael addition-curable composition may comprise: A) at least one reactive donor capable of providing two or more nucleophilic carbanions; B) at least one reactive acceptor comprising two or more carbon-carbon double bonds; C) a catalyst for catalyzing the Michael addition crosslinking reaction between at least one reactive donor and at least one reactive acceptor; and D) a co-catalyst comprising a metal oxide or metal salt, wherein the catalyst comprises at least one quaternary salt having the following structural formula I:

[0102] R 1 R 2 R 3 R 4 M + X- (Formula I)

[0103] In this formula,

[0104] R 1 R 2 R 3 and R 4 Each is independently selected from C1-C12 alkyl, C6-C14 aryl, C7-C15 alkylaryl, C7-C15 aralkyl, and any combination thereof, or R 1 R 2 R 3 and R 4 Any two of them, together with the M atom to which they are attached, form a heterocycle; M is selected from N or P, preferably from N; X - It is derived from at least one acid, at least one acid anhydride, or a combination thereof; and wherein the metal oxide or metal salt has a pH in the range of 8 to 12.

[0105] In this embodiment, at least one reactive donor and at least one reactive acceptor are similar to those described above. However, quaternary salts (including quaternary ammonium salts) can be derived from acids or anhydrides as catalysts in the Michael addition crosslinking reaction between reactive donors and acceptors, and combined with metal oxides or metal salts having a specific pH value. Surprisingly, this combination can provide a synergistic effect. The aforementioned metal oxides or metal salts having a specific pH value can particularly enhance the catalytic efficiency of at least one of the aforementioned quaternary salts as catalysts in the Michael addition crosslinking system and improve the curing rate of the curing system, especially when the amount of catalyst is significantly reduced. In addition, the Michael addition curing system described herein is particularly suitable for curing at low temperatures and is therefore suitable as a coating for coating heat-sensitive substrates (especially wood substrates). Furthermore, the aforementioned metal oxides and metal salts can also increase the hardness of the Michael addition curing system described herein.

[0106] Furthermore, Michael addition curing systems are highly adaptable and can be applied to a wide range of Michael addition reactions between reactive donors and reactive acceptors based on various resin systems. For example, the Michael addition curing systems described herein are applicable to reaction systems based on epoxy resins, polyester resins, polyacrylic resins, polyurethane resins, di- or polyol-based compounds, or combinations thereof.

[0107] In addition to the components described above, the Michael addition-curing compositions according to this document may also contain metal oxides or metal salts. As mentioned above, metal oxides or metal salts are compounds that can dissociate metal ions when added to a system, and are therefore basic. In some embodiments, the metal oxides or metal salts have a pH in the range of 8 to 12. In other embodiments, the metal oxides or metal salts have a pH in the range of 8 to 11, 8 to 10, 8 to 9, 9 to 11, 9 to 10, or 10 to 11.

[0108] It is well known that metal oxides or metal salts, particularly magnesium oxide, aluminum oxide, metal silicates (such as magnesium aluminum silicate), and combinations thereof, are commonly used in lubricants, food additives, ceramics, animal feed additives, and other fields, and their application in paints and coatings is very rare. Without being bound by theory, metal oxides or metal salts can particularly enhance the catalytic efficiency of quaternary salts as catalysts in Michael addition curing systems and increase the curing rate of the curing system. Therefore, in the context of this application, such basic metal oxides or metal salts can also be referred to as promoters. Furthermore, the application of promoters is particularly suitable for situations where the amount of catalyst is significantly reduced.

[0109] In embodiments of the invention, the metal oxide or metal salt comprises one or more metals selected from alkali metals, alkaline earth metals, and aluminum. In some embodiments, the alkali metal is selected from lithium (Li), sodium (Na), potassium (K), rubidium (RB), cesium (Cs), and francium (Fr), preferably sodium and potassium; and the alkaline earth metal is selected from beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra), preferably magnesium and calcium. In some embodiments, the alkali metal oxide or metal salt comprises one metal selected from alkali metals, alkaline earth metals, and aluminum, and preferably comprises magnesium, aluminum, calcium, or sodium. In some embodiments, the alkali metal oxide or metal salt comprises a combination of two or more metals selected from alkali metals, alkaline earth metals, and aluminum, such as a combination of aluminum and magnesium or a combination of sodium and aluminum.

[0110] In the embodiments described herein in which a metal oxide is used to promote the catalyst, the metal oxide may be selected from one or more of alkali metal oxides, alkaline earth metal oxides, and alumina, preferably selected from magnesium oxide, alumina, or combinations thereof. As an example of magnesium oxide, any commercially available magnesium oxide may be used, such as those commercially available under the trademarks ZH-V4I and ZH-V2-1 from Wuxi Zehui Chemical Co., Ltd. As an example of alumina, any commercially available alumina may be used, such as white fused alumina 500# or white fused alumina F800 commercially available from Shandong Luxin Sisha Taishan Abrasive Co., Ltd.

[0111] In the embodiments described herein where a metal salt is used to promote the catalyst, the metal salt is selected from one or more metal carbonates and metal silicates, preferably including sodium carbonate, calcium carbonate, calcium silicate, sodium aluminum silicate, magnesium aluminum silicate, and combinations thereof. Examples of sodium carbonate include any commercially available sodium carbonate, such as sodium carbonate available from Shandong Haihua Co., Ltd.; examples of calcium carbonate include any commercially available calcium carbonate, such as calcium carbonate available from Shangdong Langfang Qianyao Technology Co., Ltd.; examples of sodium aluminum silicate include any commercially available sodium aluminum silicate, such as sodium aluminum silicate available from Kunshan Shengan Biological Co., Ltd.; and examples of magnesium aluminum silicate include any commercially available magnesium aluminum silicate, such as 3M magnesium aluminum silicate available from 3M Company. TM Ceramic microsphere series, such as W-210, W-410 and W-610 microspheres.

[0112] In one embodiment, as used herein, the amount of metal oxide or metal salt may vary depending on the nature of the composition. Preferably, based on the total weight of the composition, the metal oxide or metal salt is present in an amount of 0.5 wt% to 50 wt%, preferably in an amount of 1 wt% to 40 wt%, more preferably in an amount of 1 wt% to 30 wt%, even more preferably in an amount of 1 wt% to 20 wt%, even more preferably in an amount of 1 wt% to 10 wt%, even more preferably in an amount of 1 wt% to 8 wt%, and particularly preferably in an amount of 2 wt% to 7 wt%.

[0113] Unbound by theory, the Michael addition-curing compositions described herein may contain the aforementioned basic metal oxides or metal salts and maintain appropriate curing rates even with very low amounts of quaternary catalysts (e.g., 1.0 wt% or less or 0.9 wt% or less based on the total weight of the composition), which was unexpected prior to this application.

[0114] Unbound by theory, the Michael addition curing compositions containing such metal oxides or metal salts described herein can achieve coatings with significantly improved hardness after curing, compared to comparable Michael addition curing compositions that do not contain the aforementioned metal oxides or metal salts.

[0115] The MA-curable compositions described herein may also contain one or more solvents to adjust the viscosity of the composition to achieve the desired processability.

[0116] In some embodiments, the solvent includes ethanol. Surprisingly, it has been found that incorporating a certain amount of ethanol into the MA-curable compositions described herein can result in a longer pot life or gel time for compositions or coating compositions formulated therefrom, without adversely affecting their curing rate. In some embodiments, the solvent contains at least about 2% by weight, preferably at least about 5% by weight, and more preferably at least about 10% by weight of ethanol relative to the total weight of the solvent. In many embodiments, one or more solvents further include: (A) alcohols other than ethanol, (B) esters, (C) ketones, (D) ethers, (E) aliphatic solvents, (F) aromatic solvents, (G) alkylated aromatic solvents, or (H) combinations thereof.

[0117] In some embodiments, the solvent may include other alcohols, such as methanol, isopropanol, isobutanol, n-propanol, n-butanol, 2-butanol, pentanol, tert-pentanol, neopentanol, n-hexanol, ethylene glycol, etc.; esters, such as ethyl acetate, butyl acetate, methoxypropyl acetate, isobutyl acetate, etc.; ketones, such as methyl ethyl ketone, methyl n-pentyl ketone, etc.; ethers, such as ethylene glycol butyl ether, etc.; aliphatic solvents, such as solvent oils, etc.; and aromatic or alkylated aromatic solvents, such as toluene, xylene, etc.

[0118] When the solvent includes alcohols and other non-alcohol solvents, the weight percentages of the alcohol solvent and the other non-alcohol solvents can vary within a wide range. Preferably, the alcohol solvent is present in a weight percentage ranging from about 10% to 50% by weight, preferably from about 15% to 50% by weight, and more preferably from about 20% to 40% by weight, relative to the total weight of the solvent. Furthermore, preferably, the other non-alcohol solvents are present in a weight percentage ranging from about 50% to 90% by weight, preferably from 50% to 85% by weight, and more preferably from 60% to 80% by weight, relative to the total weight of the solvent.

[0119] In one specific embodiment, the solvent further includes butyl acetate, isobutanol, or a combination thereof.

[0120] In one embodiment, the amount of solvent relative to the total weight of the composition can vary over a wide range, preferably from 0.1% by weight to 35% by weight. In some embodiments, where at least one reactive donor comprises at least one reactive diluent, for example, to reduce the VOC content of the composition, preferably, the composition contains as little solvent as possible relative to the total weight of the composition, preferably 30% by weight or less, more preferably 15% by weight or less, and even more preferably 10% by weight or less of solvent. In some other embodiments, where at least one reactive donor comprises more than 90% by weight of at least one reactive diluent, for example, the amount of solvent used in the coating composition may be less than 5% by weight, preferably less than 3% by weight, more preferably less than 2% by weight. In specific embodiments, such as where at least one reactive donor comprises 100% by weight of reactive diluent, the coating composition may contain no solvent.

[0121] In embodiments, the compositions described herein may optionally include other additional additives commonly used in coating compositions, which do not adversely affect the composition or the cured product obtained therefrom. Suitable additives include, for example, those that improve the processing or manufacturing properties of the composition, enhance the aesthetics of the composition or the cured product obtained therefrom, or improve specific functional properties or characteristics (such as adhesion to a substrate) of the composition or the cured product obtained therefrom. Additives that may be included are, for example, selected from tackifiers, curing accelerators, open time regulators, pigments and fillers, surfactants, lubricants, defoamers, dispersants, UV absorbers, colorants, coalescing agents, thixotropic agents, antioxidants, stabilizers, preservatives, fungicides, or combinations thereof, to provide the desired performance as needed. The amount of each optional component is preferably sufficient to achieve its intended purpose without adversely affecting the composition or the cured product obtained therefrom.

[0122] In some embodiments, the MA-curable composition includes a quantity of one or more epoxy functional components. The epoxy functional components may be present as a single component of the MA-curable composition, or they may be present as part of a reactive donor and / or reactive acceptor in the MA-curable composition.

[0123] In other embodiments, the MA-curable composition is substantially free of epoxy functional components. As used herein, “substantially free of epoxy functional components” means that the composition contains no more than about 3% by weight, preferably no more than about 2.8% by weight, and more preferably no more than about 2.5% by weight of epoxy functional components relative to the total weight of the composition.

[0124] When an epoxy functional component is added as a separate component to the MA-curable composition described herein, the amount of the epoxy functional component is based on the weight of the added separate component relative to the total weight of the MA-curable composition. When an epoxy functional component is added to the MA-curable composition by covalent bonding to a reactive donor and / or a reactive acceptor, the amount of the epoxy functional component is determined based on the weight of the raw material used to provide the epoxy functional groups relative to the total weight of the MA-curable composition.

[0125] The MA-curable compositions described herein are environmentally acceptable, i.e., substantially free of volatile organic compounds (VOCs). In some embodiments, the compositions have a VOC content of 420 g / L or less, as measured by ISO 11890-1:2007. In other embodiments, the compositions have a VOC content of 400 g / L or less, preferably 200 g / L. The VOC content is determined based on the total weight of the composition.

[0126] After mixing the components of the MA-curable composition described herein, the resulting composition has a relatively long pot life and exhibits particularly excellent processability. In one embodiment, after mixing the components of the composition, the resulting mixture has a pot life of 6 hours or longer, preferably 7 hours or longer, and more preferably 8 hours or longer, and even more preferably 10 hours or longer at 25°C.

[0127] The MA-curable compositions described herein can be cured at a temperature determined by the application process, the nature of the substrate to which the composition is applied, or the end use of the composition. In some embodiments, curing is carried out at ambient temperature, particularly in the range of about 15°C to 40°C, and preferably in the range of about 20°C to 27°C. In other embodiments, it can be cured under high-temperature baking conditions, such as above 100°C.

[0128] The MA-curable compositions described herein can be cured for an appropriate period of time at a given curing temperature. For example, at room temperature, curing can be completed in 7 days or less, preferably 5 days or less, and more preferably 3 days or less.

[0129] In one embodiment, after mixing the components of the composition, the resulting composition is applied as a wet coating of about 100 micrometers thickness and dried at room temperature for 24 hours. The resulting cured coating exhibits a pendulum impact hardness of about 5 or greater, preferably about 20 or greater, more preferably about 40 or greater, even more preferably about 80 or greater, and even more preferably 100 or greater. As used herein, “pendulum impact hardness” is determined according to ASTM D-4366 (the standard test method for determining the hardness of organic coatings by means of a pendulum damping test).

[0130] The MA-curable compositions described herein are suitable for a variety of applications and can be used to manufacture coatings, adhesives, sealants, foams, elastomers, films, molded articles, or inks.

[0131] Prior to use, the MA-curable compositions described herein can be stored in various ways. In some embodiments, the components of the Michael addition-curable composition, such as at least one reactive donor, at least one reactive acceptor, and catalyst, are stored separately. In other embodiments, some components of the Michael addition-curable composition may be premixed; for example, at least one reactive donor and at least one reactive acceptor may be premixed, and the catalyst may be stored separately, or the catalyst may be premixed with at least one reactive donor or at least one reactive acceptor, and the remaining components may be stored separately. In use, at least one reactive donor, at least one reactive acceptor, catalyst, and other components are simply mixed in a mixing container at a predetermined weight ratio. The mixed curable composition can be shaped using various methods familiar to those skilled in the art, such as by molding, coating, extrusion, etc. The resulting composition can be cured to form a desired cured product. Therefore, the content described herein also relates to cured products obtained and / or obtainable through the MA-curable compositions described herein.

[0132] The Michael addition-curable compositions described herein are particularly suitable for application as coating compositions in the coating industry. Therefore, this specification provides coating compositions comprising the Michael addition-curable compositions described herein. The compositions can be applied in a variety of ways familiar to those skilled in the art, including spraying (e.g., air-assisted, airless, or electrostatic spraying), brushing, rolling, overflow, and dipping. In the embodiments described herein, the mixed coating composition is applied by spraying.

[0133] The coating composition can be applied at various wet film thicknesses. In embodiments, the coating composition is applied at a wet film thickness of about 100 μm to about 400 μm, preferably about 100 μm to 200 μm. The applied coating can be cured by air drying at room temperature or by accelerated drying using various drying devices (e.g., ovens familiar to those skilled in the art).

[0134] This specification provides a coated article comprising a substrate having at least one main surface and a cured coating formed by the coating composition described herein, the cured coating being applied directly or indirectly at least partially to the main surface.

[0135] As described herein, the substrate has at least one, preferably two, main surfaces opposite each other. In some embodiments, the main surfaces of the substrate may contain polar groups, such as hydroxyl groups, amino groups, thiol groups, etc., to promote adhesion. The hydroxyl groups on the substrate surface may be derived from the substrate itself, such as from cellulose when the substrate is a woody substrate, or may be introduced onto the substrate surface by surface treatment on the main surfaces of the substrate, such as by corona treatment, or by pretreatment of a metal substrate, as known to those skilled in the art.

[0136] The coating compositions described herein can be applied to a wide variety of substrates. Suitable examples include, but are not limited to, natural and engineered building and construction materials, freight containers, flooring materials, walls, furniture, other building materials, motor vehicles, motor vehicle parts, aircraft parts, trucks, rail vehicles and engines, bridges, water towers, telephone towers, wind towers, radio towers, lighting fixtures, statues, signboard supports, fences, railroad sidings, tunnels, pipes, ship components, machinery parts, laminates, equipment parts, electrical appliances, and packaging. Exemplary substrates include, but are not limited to, wood, metal, plastic, ceramic, cement board, or any combination thereof. In one embodiment, the substrate is a wood substrate. In another embodiment, the substrate is a metal, preferably stainless steel.

[0137] Example

[0138] The following examples describe the contents described herein in more detail. They are for illustrative purposes only, as various modifications and variations will be apparent to those skilled in the art given the scope of the contents described herein. Unless otherwise stated, all parts, percentages, and ratios reported in the following examples are by weight, and all reagents used in the examples are commercially available and can be used without further processing.

[0139] Example 1: Reactive Donor

[0140] The reactive donor A1 is a malonate-functionalized polyester resin, which is commercially available as ACURE 510-170 (Allnex USA).

[0141] Reactive donor A2 was prepared as follows: At room temperature, 187.40 g of trimethylolpropane, 359.43 g of neopentyl glycol, 86.02 g of adipic acid, and 596.00 g of phthalic anhydride were charged into a four-necked flask equipped with a thermometer, top stirrer, gas inlet, and distillation apparatus. Nitrogen gas was supplied through the gas inlet for nitrogen protection. The resulting reaction mixture was then slowly heated to approximately 180 °C and maintained at this temperature until distilled water was produced. The temperature of the mixture was increased to 230 °C. The mixture was then allowed to stand until an acid value below 2 mg KOH / g was achieved. The mixture was then cooled to below 150 °C, and then 216.41 g of tert-butyl acetoacetate was added. The temperature of the mixture was increased to 120 °C to proceed with the reaction. The distillate tert-butanol was collected, and the mixture was maintained at this temperature until the distillation temperature did not exceed 78 °C. The temperature of the mixture was increased to 160 °C. After distillation, the mixture was cooled to below 100°C and then mixed with 429.20 g of n-butyl acetate (n-BA) with a solid content of about 70% by weight. The resulting reactive donor A2 has the following properties: Mn = 4339, Mw = 19494, PDI = 4.5, and Tg = 6°C.

[0142] Reactive donor A3, an epoxy-based reactive donor, was prepared as follows: At room temperature, 209.36 g of epoxy resin (NanYa, EEW: 772 g / mol) and 90.64 g of tert-butyl acetoacetate (t-BAA) were charged into a four-necked flask equipped with a thermometer, top stirrer, gas inlet, and distillation apparatus. Nitrogen gas was supplied through the gas inlet for nitrogen protection. The resulting reaction mixture was then slowly heated to approximately 130 °C, the distillate (tert-butanol) was collected, and maintained at this temperature until the distillation temperature did not exceed 78 °C. The temperature of the mixture was then raised to 160 °C. After distillation, the mixture was then cooled to below 100 °C and then mixed with 102.96 g of n-butyl acetate (n-BA) with a solids content of approximately 70 wt%.

[0143] The reactive donor A4 is ethyl acetoacetate (CAS No. 141-97-9) with a solids content of approximately 98% and a CH functionality of 2.

[0144] Reactive donor A5, a polyol-based reactive donor, was prepared as follows: At room temperature, 195.4358 g (1.8765 mol) of neopentyl glycol and 604.5642 g (3.7530 mol) of tert-butyl acetoacetate were charged into a four-necked flask equipped with a thermometer, top stirrer, gas inlet, and distillation apparatus. Nitrogen gas was supplied through the gas inlet for nitrogen protection. The resulting reaction mixture was then slowly heated to approximately 105 °C and maintained at this temperature until the tert-butanol was distilled off, with the distillation temperature maintained at 78 °C ± 2 °C. The temperature of the mixture was then increased to 170 °C. When the temperature of the mixture reached 170 °C, it was maintained for a period of time until the distillation temperature was below 60 °C. The mixture was then cooled to below 60 °C. The resulting reactive donor had the following properties: molecular weight of 272.29 g / mol; solids content of approximately 91%; viscosity at 25 °C not exceeding 300 mPa·s; and CH functionality of 4.

[0145] Reactive donor A6, a polyol-based reactive donor, was prepared as follows: At room temperature, 251.451 g (1.8765 mol) of trimethylolpropane and 906.8463 g (5.6295 mol) of tert-butyl acetoacetate were charged into a four-necked flask equipped with a thermometer, top stirrer, gas inlet, and distillation apparatus. Nitrogen gas was supplied through the gas inlet for nitrogen protection. The resulting reaction mixture was then slowly heated to approximately 105 °C and maintained at this temperature until tert-butanol was distilled off, with the distillation temperature maintained at 78 °C ± 2 °C. The temperature of the mixture was then increased to 170 °C. When the temperature of the mixture reached 170 °C, it was maintained for a period of time until the distillation temperature was below 60 °C. The mixture was then cooled to below 60 °C. The resulting reactive donor had the following properties: molecular weight of 386.38 g / mol; solids content of approximately 91.3%; viscosity at 25 °C not exceeding 300 mPa·s; and CH functionality of 6.

[0146] Reactive donor A7 is a polyol-based reactive donor prepared as follows: At room temperature, 255.485 g (1.8765 mol) of pentaerythritol and 1187.37414 g (7.506 mol) of tert-butyl acetoacetate were charged into a four-necked flask equipped with a thermometer, top stirrer, gas inlet, and distillation apparatus. Nitrogen gas was supplied through the gas inlet for nitrogen protection. The resulting reaction mixture was then slowly heated to approximately 105 °C and maintained at this temperature until the tert-butanol was distilled off, with the distillation temperature maintained at 78 °C ± 2 °C. The temperature of the mixture was increased to 170 °C without exceeding 78 °C. When the temperature of the mixture reached 170 °C, it was maintained for a period of time until the distillation temperature was below 60 °C. The mixture was then cooled to below 60 °C. The resulting reactive donor has the following properties: molecular weight of 472.43 g / mol; solids content of approximately 91.6%; viscosity at 25 °C of 350 mPa·s; and CH functionality of 8.

[0147] Example 2: Reactive Receptors

[0148] Reactive acceptor B1 is an acid-free tetrafunctional polyester acrylate resin that is commercially available as ACURE 550-105 (Allnex USA).

[0149] Reactive acceptor B2 is a low-viscosity bifunctional acrylate monomer that is commercially available as Sartomer SR833 (Arkema USA).

[0150] The reactive receptor B3 is dipropylene glycol diacrylate (DPGDA).

[0151] The reactive receptor B4 is trimethylolpropane triacrylate (TMPTA).

[0152] The reactive receptor B5 is bis(trimethylolpropane)acrylate (Di-TMPTA).

[0153] Example 3: Catalyst

[0154] Catalysts C1 to C18 are prepared as follows. Each acid or anhydride shown in Table 1 is added dropwise to an aqueous solution of tetrabutylammonium hydroxide. For each acid listed in Table 1, the amount of acid is such that the stoichiometric ratio of ––OH to –COOH is 1:1. Similarly, for each anhydride used, the stoichiometric ratio is 2:1. If necessary, a certain amount of ethanol may be added to promote the dissolution of the acid or anhydride. A catalyst solution with a solid content of 20% by weight is obtained.

[0155] Table 1

[0156]

[0157]

[0158]

[0159] Example 4: Preparation of MA-curable coating composition

[0160] Various MA-curable test compositions were prepared and are listed in Table 2 as Examples 1-1 to 1-19 and Comparative Examples 1-1 to 1-4. Each MA-curable composition was formulated using the reactive donor, reactive acceptor, solvent, and catalyst shown in Table 2, with butyl acetate as the solvent. In Examples 1-1 to 1-14 and Comparative Examples 1-1 to 1-4, the weight ratio of reactive donor A1, reactive acceptor B1, solvent, and catalyst was 60:28:36:10. In Examples 1-15 to 1-19, the weight ratio of reactive donor A2, reactive acceptor B2, solvent, and catalyst was 287:83:45:41. After mixing the reactive donor, reactive acceptor, catalyst, and solvent, a certain amount of butyl acetate was selectively added to adjust the viscosity of the composition, thereby forming the MA-curable compositions of Examples 1-1 to 1-19 and Comparative Examples 1-1 to 1-4.

[0161] Example 5: Curing Properties

[0162] To determine the effect of the catalyst on the curing of the MA-curable composition, the test composition prepared as described in Example 4 and shown in Table 2 was applied to an aluminum test substrate with a wet coating thickness of 100 micrometers and cured at 25°C. The curing time, i.e., the time required for the coating to feel dry to the touch, is recorded in Table 2.

[0163] Table 2

[0164] Reactive donors Reactive receptors catalyst Curing time (h) Example 1-1 A1 B1 C1 3 Examples 1-2 A1 B1 C2 2 Examples 1-3 A1 B1 C3 1 Examples 1-4 A1 B1 C4 8 Examples 1-5 A1 B1 C5 2 Examples 1-6 A1 B1 C6 2 Examples 1-7 A1 B1 C7 2 Examples 1-8 A1 B1 C8 2 Examples 1-9 A1 B1 C9 2 Examples 1-10 A1 B1 C10 1 Examples 1-11 A1 B1 C11 1 Examples 1-12 A1 B1 C12 1 Examples 1-13 A1 B1 C13 2 Examples 1-14 A1 B1 C14 2 Examples 1-15 A2 B2 C1 1 Examples 1-16 A2 B2 C2 3 Examples 1-17 A2 B2 C4 8 Examples 1-18 A2 B2 C5 2 Examples 1-19 A2 B2 C14 1 Comparative Example 1-1 A1 B1 C15 It does not cure within 24 hours Comparative Examples 1-2 A1 B1 C16 It does not cure within 24 hours Comparative Examples 1-3 A1 B1 C17 It does not cure within 24 hours Comparative Examples 1-4 A1 B1 C18 It does not cure within 24 hours

[0165] As can be seen from Table 2, when the catalyst is a quaternary salt derived from an acid or anhydride with a pKa value in the range of 0 to 10, the MA-curable composition can be cured at room temperature or ambient temperature.

[0166] Example 6: Performance Testing

[0167] The impact hardness of the test compositions prepared as described in Example 4 and shown in Table 2 was tested. The impact hardness was tested using an impact hardness tester (BYK-Gardner GmbH) according to ASTM D-4366. The impact hardness of the test compositions was tested after a specific number of days of allowed curing. The obtained impact hardness is expressed as a count, and the results are shown in Table 3.

[0168] Table 3

[0169]

[0170]

[0171] Note: As shown in Table 3, "x" indicates uncured, and " / " indicates untested data.

[0172] The results in Table 3 show that the MA-curable compositions described herein provide cured coatings with optimal, or even excellent, hardness.

[0173] Example 7: Effect of the reaction diluent

[0174] To determine the effect of using at least one reactive diluent, test samples of the Michael addition-curable composition were prepared. These test samples are specified as Examples 2-1 to 2-10 in Table 4. The test samples were formulated with at least one reactive diluent as a reactive donor, along with a reactive acceptor and a catalyst, wherein the reactive donor and reactive acceptor are shown in Table 2, and the catalyst is C14 with a solids content of 25% by weight. No solvent was used.

[0175] In Examples 2-11, epoxy reactive donor A3 and reactive diluent A7 having CH functionality of 8 were mixed as reactive donors.

[0176] After the compositions of Examples 2-1 to 2-11 were prepared, their solid content (wt%), viscosity and VOC content were tested and recorded in Table 4, wherein the solid content and VOC content were measured according to GB / T23985-22209 / ISO 11890-1:2007, and the viscosity was measured using an Iwata-2 cup at 25°C.

[0177] Each of the test compositions labeled Examples 2-1 to 2-11 was applied to an aluminum test substrate with a wet coating thickness of 100 micrometers and cured at 25°C. The pendulum impact hardness of these cured coatings was tested at specific curing days using a pendulum impact hardness tester (BYK-Gardner GmbH) according to ASTM D-4366, and the results are expressed as counts and recorded in Table 4.

[0178] In addition, each test composition was placed in a plastic cup and cured at room temperature. The shrinkage of each composition was observed visually, and the results are recorded in Table 4.

[0179] Table 4

[0180]

[0181] Note: As shown in Table 4, "x" indicates uncured, and " / " indicates untested data.

[0182] The results in Table 4 demonstrate that the MA-curable compositions containing reactive diluents can be successfully cured and are suitable for use in coating compositions. Furthermore, the MA-curable compositions containing reactive donors exhibit high solids content, low viscosity, and low VOC content. Therefore, these compositions can be used by adding solvent during application without further dilution, thereby reducing VOC emissions into the atmosphere.

[0183] The hardness test results shown in Table 4 demonstrate that the MA-curable compositions containing reactive diluents described herein exhibit optimal, or even excellent, hardness. Furthermore, when using reactive donors with high CH functionality, the resulting MA-curable compositions exhibit additional benefits, such as excellent film shrinkage.

[0184] Example 8: The effect of solvent on pot life

[0185] To determine the effect of solvent on pot life, various MA-curable test compositions were prepared and are designated as Samples 1-10 and Examples 3-1 to 3-4 in Table 5. The test compositions were formulated using a reactive donor, a reactive acceptor, a solvent, and a catalyst. The reactive donor was a mixture of A3 and A7 in a weight ratio of 2.3:1, and the reactive acceptor was a mixture of B3 and B4 in a weight ratio of 12:30. The catalyst was C14 with a solids content of 50%, and the solvents used were as shown in Table 5. The weight ratio of the reactive donor, reactive acceptor, solvent, and catalyst was 62:33:30:3.6.

[0186] After mixing the reactive donor, reactive acceptor, catalyst, and solvent, the resulting mixture was placed in a glass bottle. To quickly screen for a more preferred solvent, the mixture was placed in a constant-temperature water bath at 40°C, and its viscosity was periodically tested using an Iwata-2 cup.

[0187] In Table 5-8, the solvent abbreviations used are as follows: n-butyl acetate as BAC; ethanol as EtOH; isopropanol as IPA; isobutanol as IBA; propylene glycol monomethyl ether acetate as PMA; and methyl pentyl ketone as MAK.

[0188] The viscosity results at 40°C are shown in Table 5.

[0189] Table 5

[0190]

[0191]

[0192] The results in Table 5 indicate that solvent mixtures of butyl acetate and ethanol provide coating compositions with the longest pot life. Adding ethanol to the solvent is particularly beneficial for extending the pot life of these compositions.

[0193] Example 9: The effect of temperature on the service life

[0194] To determine the effect of temperature on the pot life of the MA-curable compositions, various test compositions using different mixing schemes of butyl acetate, isobutanol, and ethanol were used, as shown in the tables below. Tables 6, 7, and 8 show the viscosity of the MA-curable test compositions of Examples 3-1 to 3-4 over time at temperatures of 28°C, 30°C, and 35°C.

[0195] Table 6

[0196]

[0197] At a curing temperature of 28°C, when using a mixture of butyl acetate, isobutanol, and ethanol as a solvent, the MA-curable compositions described herein have a pot life of more than 3 hours.

[0198] Table 7

[0199]

[0200] Note: As shown in Table 7, " / " indicates untested data.

[0201] At a curing temperature of 30°C, when using a mixture of butyl acetate, isobutanol, and ethanol as a solvent, the MA-curable compositions described herein exhibit a pot life of more than 2.5 hours.

[0202] Table 8

[0203]

[0204] As can be seen from the results shown in Table 8, at a curing temperature of 35°C, when a mixture of butyl acetate, isobutanol, and ethanol is used as a solvent, the MA-curable coating composition described herein exhibits a pot life of more than 2 hours.

[0205] Example 9: Comparison with other Michael addition catalysts

[0206] To compare the MA catalysts described herein with commercially available, previously known MA catalysts, MA-curable compositions of Examples 4-1 to 4-7 and Comparative Examples 4-1 to 4-7 were formulated using reactive donors, reactive acceptors, solvents, and catalysts. For Examples 4-1 to 4-7, the reactive donor was a mixture of A3 and A7 in a weight ratio of 2.3:1, the reactive acceptor was a mixture of B3 and B4 in a weight ratio of 12:30, and the catalyst C14 had a 50% solids content. In Comparative Examples 4-1 to 4-7, the catalyst used was ACURE 500, a capped potential base catalyst commercially available from Allnex USA. For all compositions in these examples, the solvent used was butyl acetate, wherein the weight ratio of reactive donor, reactive acceptor, and solvent was 55.5:32:17.

[0207] After mixing the components of the compositions of Examples 4-1 to 4-7 and Comparative Examples 4-1 to 4-7, the pot life was measured. Each composition of Examples 4-1 to 4-7 was applied to a test substrate in a wet coating thickness of 200 micrometers and cured at room temperature. After 18 hours of curing, the pendulum impact hardness of the coating was tested using a BYK-Gardner pendulum impact hardness tester according to ASTM D-4366. The obtained pendulum impact hardness is expressed as a count, and the results are recorded in Table 9.

[0208] Table 9

[0209] catalyst Amount of catalyst Impact Hardness gel time Example 4-1 C14 1.0％ 61 >2h Example 4-2 C14 1.2％ 45 >2h Example 4-3 C14 1.4％ 89 >2h Example 4-4 C14 1.8％ 100 2h Examples 4-5 C14 2.0％ 105 1h Examples 4-6 C14 2.2％ 85 50min Examples 4-7 C14 2.4％ 115 40min Comparative Example 4-1 Acure500 1.0％ 86 35min Comparative Example 4-2 Acure500 1.2％ 87 30min Comparative Example 4-3 Acure500 1.4％ 83 30min Comparative Example 4-4 Acure500 1.8％ 65 20min Comparative Examples 4-5 Acure500 2.0％ 64 20min Comparative Examples 4-6 Acure500 2.2％ 77 20min Comparative Examples 4-7 Acure500 2.4％ 66 20min

[0210] As can be seen from the results shown in Table 9, the MA-curable compositions with catalysts as described herein exhibit superior properties, including better hardness and longer pot life, compared to systems using known commercially available alternative catalysts.

[0211] Example 10: The effect of co-catalysts on the catalytic activity of catalysts

[0212] The metal oxides or metal salts D1-D5 listed in Table 10 are used as cocatalysts in the following examples.

[0213] Table 10

[0214] serial number type pH solubility D1 magnesium oxide 9.43 Slightly soluble D2 Alumina 8.04 Slightly soluble D3 Sodium carbonate 10.61 Completely soluble D4 Calcium carbonate 8.93 Slightly soluble D5 Magnesium aluminum silicate (ceramic beads) 9.64 Slightly soluble

[0215] The examples in this section examine the effect of co-catalysts, i.e., metal oxides or salts, on the catalytic activity of catalysts in various systems.

[0216] The Michael addition-curing compositions of Examples 5-1 to 5-10 and Comparative Examples 5-11 to 5-18 were formulated using a reactive donor, a reactive acceptor, a solvent, a catalyst, and a co-catalyst in a weight ratio of (donor, acceptor, and additive):catalyst:co-catalyst:solvent = 100:3.6:4:30. The specific types of reactive donors, reactive acceptors, catalysts, and co-catalysts used in each example are shown in Table 11, and the solvent was a mixture of 90% by weight butyl acetate and 10% by weight ethanol. After mixing the reactive donor, reactive acceptor, catalyst, and solvent, a certain amount of butyl acetate may be selectively added to adjust the viscosity of the composition, thereby forming a Michael addition-curing composition. Comparative Examples 5-11 to 5-17 did not contain the co-catalyst component; Comparative Examples 5-17 and 5-18 were Michael addition-curing systems formulated with Acure catalyst (C19).

[0217] The components described in the examples and comparative examples shown in Table 11 below were mixed, and the time required for the resulting mixture to reach a non-flowing gel state was measured. The gel time was then recorded in Table 11.

[0218] Table 11

[0219] donor receptor catalyst co-catalyst gel time Example 5-1 A3 B2 C14 D1 15min Example 5-2 A3 B2 C14 D2 60min Example 5-3 A3 B2 C14 D3 90min Example 5-4 A3 B2 C14 D4 20min Example 5-5 A3 B2 C14 D5 60min Examples 5-6 A2 B2 C14 D1 15min Examples 5-7 A2 B2 C1 D1 15min Examples 5-8 A2 B2 C2 D1 10min Examples 5-9 A2 B2 C4 D1 10min Examples 5-10 A2 B2 C5 D1 30min Comparative Example 5-11 A3 B2 C14 / >4h Comparative Example 5-12 A2 B2 C14 / >4h Comparative Example 5-13 A2 B2 C1 / >24h Comparative Example 5-14 A2 B2 C2 / 16h Comparative Example 5-15 A2 B2 C4 / >24h Comparative Example 5-16 A2 B2 C5 / 16h Comparative Example 5-17 A1 B2 C19 / >4h Comparative Example 5-18 A1 B2 C19 D1 >4h

[0220] The results in Table 11 show that, compared with comparable Michael addition curing systems that do not contain the aforementioned metal oxides or metal salts, metal oxides or metal salts significantly improved the curing rate of Michael addition curing systems containing quaternary salts as catalysts, but had no effect on those Michael addition curing systems containing Acure 500, a potential catalyst available from Allnex.

[0221] Furthermore, the results in Table 11 also show that the aforementioned metal oxides or metal salts with specific pH values ​​promote quaternary salt catalysts in both epoxy curing systems and polyester curing systems, and are unaffected by the reactive donors and reactive acceptors of the curing system.

[0222] Example 11: Michael addition-curing composition with reduced amount of catalyst

[0223] Since we found that adding a co-catalyst to Michael addition-curing compositions can significantly shorten the gel time of the compositions, we investigated compositions with reduced catalyst amounts. Examples 6-2 to 6-10 shown in Table 12 used less catalyst compared to Example 6-1. Their gel times were tested and recorded in Table 12.

[0224] Table 12

[0225]

[0226]

[0227] The results in Table 12 show that, compared with the standard Michael addition curing system without metal oxides, the Michael addition curing system described in this paper still exhibits a comparable curing rate due to the presence of metal oxides, even with a three-fold reduction in the amount of quaternary ammonium catalyst.

[0228] Example 12: Effect of co-catalyst on coating hardness of Michael addition curing system

[0229] The examples in this section examine the effect of metal oxides or salts on the coating hardness of epoxy-based Michael addition curing systems.

[0230] The compositions prepared in Examples 5-2 and 5-5 and Comparative Example 5-11 as shown in Table 12 above were applied to aluminum substrates with a wet coating thickness of 200 micrometers and dried at room temperature for different days. The impact hardness of the cured coatings was then measured according to ASTM D-4366. The results are recorded in Table 13 below.

[0231] Table 13

[0232] 1 day 2 days 3 days 5 days 10 days Example 5-2 84 105 111 119 121 Example 5-5 112 130 132 133 134 Comparative Example 5-11 78 103 107 109 112

[0233] The results in Table 13 show that the metal oxides or metal salts described in this paper improve the coating hardness of the Michael addition curing system.

[0234] Implementation Plan

[0235] The following implementation schemes are envisioned. All combinations of features and implementation schemes are envisioned.

[0236] Implementation Scheme 1: A Michael addition-curable composition comprising: A) at least one reactive donor capable of providing two or more nucleophilic carbanions; B) at least one reactive acceptor comprising two or more carbon-carbon double bonds; and C) a catalyst for catalyzing a Michael addition crosslinking reaction between at least one reactive donor and at least one reactive acceptor, wherein the catalyst comprises at least one quaternary salt having a compound structure of Formula I.

[0237] R 1 R 2 R 3 R 4 M + X - (Formula I)

[0238] In this formula,

[0239] R 1 R 2 R3 and R 4 Each is independently selected from C1-C12 alkyl, C6-C14 aryl, C7-C15 alkylaryl, C7-C15 aralkyl, and any combination thereof, or R 1 R 2 R 3 and R 4 Any two of them, together with the M atoms to which they are attached, form a heterocycle;

[0240] M is N or P; and

[0241] X - Derived from at least one acid, at least one acid anhydride, or a combination thereof, wherein X - Having a pKa value in the range of 0 to 10, wherein the pKa value is obtained by measuring in an aqueous solution of at least one acid, at least one acid anhydride, or a combination thereof at 25°C, and wherein X - It is not an acid or anhydride derived from carbonic acid or carbamic acid.

[0242] Implementation Scheme 2: According to the implementation scheme described in Implementation Scheme 1, wherein X - Derived from at least one acid, at least one anhydride, or a combination thereof, with a pKa value in the range of 1 to 8.

[0243] Implementation Scheme 3: According to any one of Implementation Schemes 1 to 2, the at least one acid includes one or more of aliphatic carboxylic acids, aromatic carboxylic acids, alicyclic carboxylic acids, inorganic weak acids or their anhydrides, and any combination thereof.

[0244] Implementation Scheme 4: According to any one of Implementation Schemes 1 to 3, wherein at least one acid or at least one anhydride comprises formic acid, acetic acid, oxalic acid, glycolic acid, monohaloacetic acid, dihaloacetic acid, trihaloacetic acid, propionic acid, malonic acid, acrylic acid, lactic acid, propynic acid, glyceric acid, pyruvic acid, n-butyric acid, isobutyric acid, 3-butenoic acid, succinic acid, maleic acid, tartaric acid, n-valeric acid, isovaleric acid, pentenoic acid, glutamate, itaconic acid, citraconic acid, mesoconic acid, glutamic acid, n-hexanoic acid, isohexanoic acid, hexenoic acid, citric acid, sebacic acid, ethylenediaminetetraacetic acid (EDTA), 1,2-cyclohexanedicarboxylic acid, gluconic acid, phthalic acid, trimellitic acid, pyromellitic acid, arsenic acid, hydrofluoric acid, hydrogen selenic acid, selenite, and one or more of their anhydrides.

[0245] Implementation Scheme 5: According to any one of Implementation Schemes 1 to 4, wherein at least one reactive donor comprises two or more acidic protons CH from an activated methylene group, a methine group, or a combination thereof.

[0246] Implementation Scheme 6: According to the implementation scheme of Implementation Scheme 5, wherein two or more acidic protons CH of the activated methylene group, methine group, or combination thereof are derived from acetoacetate or malonate compounds.

[0247] Implementation Scheme 7: According to any one of Implementation Schemes 1 to 6, at least one reactive donor comprises a reactive donor having a backbone based on epoxy resin, polyester resin, acrylic resin, polyurethane resin or a combination thereof.

[0248] Implementation Scheme 8: According to any one of Implementation Schemes 1 to 7, wherein at least one reactive donor comprises at least one reactive diluent obtained by transesterification of at least one diol or at least one polyol.

[0249] Implementation Scheme 9: An embodiment according to any one of Implementation Schemes 1 to 8, wherein the Michael addition-curing composition has a solids content of 70% by weight or more, preferably 80% by weight or more, and more preferably 90% by weight or more.

[0250] Implementation Scheme 10: An embodiment according to any one of Implementation Schemes 1 to 9, wherein the Michael addition-curing composition has a volatile organic compound (VOC) content of 400 g / L or less, as measured by ISO 11890-1:2007.

[0251] Implementation Scheme 11: According to any one of Implementation Schemes 1 to 10, wherein at least one reactive acceptor comprises a carbon-carbon double bond having the structure of Formula II:

[0252] C = C - CX (Equation II)

[0253] Where CX represents any one of the following groups: aldehyde group (-CHO), ketone group (-CO-), ester group (-C(O)O-), and cyano group (-CN).

[0254] Implementation Scheme 12: According to any one of Implementation Schemes 1 to 11, the scheme further includes one or more solvents.

[0255] Implementation Scheme 13: According to the implementation scheme described in Implementation Scheme 12, one or more solvents include ethanol.

[0256] Implementation Scheme 14: According to the implementation scheme of Implementation Scheme 12, one or more solvents further include: (A) alcohols other than ethanol, (B) esters, (C) ketones, (D) ethers, (E) aliphatic solvents, (F) aromatic solvents, (G) alkylated aromatic solvents, or (H) combinations thereof.

[0257] Implementation Scheme 15: According to the implementation scheme of Implementation Scheme 12, one or more solvents further include butyl acetate, isobutanol, or combinations thereof.

[0258] Implementation Scheme 16: The implementation scheme according to any one of Implementation Schemes 1 to 14 further includes at least one additional catalyst.

[0259] Implementation Scheme 17: According to any one of Implementation Schemes 1 to 16, wherein after mixing the components of the composition, the resulting mixture has a pot life of 2 hours or longer at 25°C.

[0260] Implementation Scheme 18: According to any one of Implementation Schemes 1 to 17, wherein the Michael addition curing composition is cured in the range of 20°C to 27°C.

[0261] Implementation Scheme 19: According to any one of Implementation Schemes 1 to 18, wherein the Michael addition curing composition is cured in a range of 20°C to 27°C for 7 days or less.

[0262] Embodiment 20: A coating composition comprising the composition according to any one of Embodiments 1 to 19.

[0263] Implementation Scheme 21: According to the embodiment of Implementation Scheme 20, the coating composition is applied with a wet coating thickness of 100 micrometers and dried for 24 hours to form a cured coating, and the cured coating exhibits a pendulum impact hardness of about 5 or greater, as measured by ASTM D-4366.

[0264] Embodiment 22: A coated article comprising: 1) a substrate having at least one main surface; and 2) a cured coating formed by a coating composition according to any one of Embodiments 20 or 21, the cured coating being applied directly or indirectly at least partially to the main surface.

[0265] Implementation Scheme 23: According to the implementation scheme of Implementation Scheme 22, the substrate includes wood, metal, plastic, ceramic, cement board or any combination thereof.

[0266] Implementation Scheme 24: A Michael addition-curable composition comprising: A) at least one reactive donor capable of providing two or more nucleophilic carbanions; B) at least one reactive acceptor comprising two or more carbon-carbon double bonds; C) a catalyst for catalyzing a Michael addition crosslinking reaction between at least one reactive donor and at least one reactive acceptor; and D) a co-catalyst comprising at least one metal oxide, at least one metal salt, or a combination thereof, wherein the catalyst comprises at least one quaternary salt having the following structural formula I.

[0267] R 1 R 2 R 3 R 4 M + X - (Formula I)

[0268] In this formula,

[0269] R 1 R 2 R 3 and R 4 Each is independently selected from C1-C12 alkyl, C6-C14 aryl, C7-C15 alkylaryl, C7-C15 aralkyl, and any combination thereof, or R 1 R 2 R 3 and R 4 Any two of them, together with the M atoms to which they are attached, form a heterocycle;

[0270] M is selected from N or P, preferably from N; and

[0271] X - Derived from at least one acid, at least one of its anhydrides, or a combination thereof;

[0272] The metal oxides, metal salts, or combinations thereof have a pH in the range of 8 to 12.

[0273] Implementation Scheme 25: According to the implementation scheme described in Implementation Scheme 24, wherein X - Derived from at least one acid, at least one anhydride, or a combination thereof, with a pKa value in the range of 1 to 8.

[0274] Implementation Scheme 26: According to any one of Implementation Schemes 24 to 25, the at least one acid includes one or more of aliphatic carboxylic acids, aromatic carboxylic acids, alicyclic carboxylic acids, inorganic weak acids or their anhydrides, and any combination thereof.

[0275] Implementation Scheme 27: According to any one of Implementation Schemes 24 to 26, wherein at least one acid or at least one anhydride comprises formic acid, acetic acid, oxalic acid, glycolic acid, monohaloacetic acid, dihaloacetic acid, trihaloacetic acid, propionic acid, malonic acid, acrylic acid, lactic acid, propynic acid, glyceric acid, pyruvic acid, n-butyric acid, isobutyric acid, 3-butenoic acid, succinic acid, maleic acid, tartaric acid, n-valeric acid, isovaleric acid, pentenoic acid, glutamate, itaconic acid, citraconic acid, mesoconic acid, glutamic acid, n-hexanoic acid, isohexanoic acid, hexenoic acid, citric acid, sebacic acid, ethylenediaminetetraacetic acid (EDTA), 1,2-cyclohexanedicarboxylic acid, gluconic acid, phthalic acid, trimellitic acid, pyromellitic acid, arsenic acid, hydrofluoric acid, hydrogen selenic acid, selenite, and one or more of their anhydrides.

[0276] Implementation Scheme 28: According to any one of Implementation Schemes 24 to 27, wherein at least one reactive donor comprises two or more acidic protons CH from an activated methylene group, a methine group, or a combination thereof.

[0277] Implementation Scheme 29: According to the implementation scheme of Implementation Scheme 28, two or more acidic protons CH of the activated methylene group, methine group or combination thereof are derived from acetoacetate or malonate compounds.

[0278] Implementation Scheme 30: According to any one of Implementation Schemes 24 to 29, wherein at least one reactive donor comprises a reactive donor having a backbone based on epoxy resin, polyester resin, acrylic resin, polyurethane resin or a combination thereof.

[0279] Implementation Scheme 31: According to any one of Implementation Schemes 24 to 30, wherein at least one reactive donor comprises at least one reactive diluent obtained by transesterification of at least one diol or at least one polyol.

[0280] Embodiment 32: An embodiment according to any one of embodiments 24 to 31, wherein the Michael addition-curing composition has a solids content of 70% by weight or more, preferably 80% by weight or more, and more preferably 90% by weight or more.

[0281] Implementation Scheme 33: An embodiment according to any one of Implementation Schemes 24 to 32, wherein the Michael addition-curing composition has a volatile organic compound (VOC) content of 400 g / L or less, as measured by ISO 11890-1:2007.

[0282] Implementation Scheme 34: According to any one of Implementation Schemes 24 to 33, wherein at least one reactive acceptor comprises a carbon-carbon double bond having the structure of Formula II:

[0283] C = C - CX (Equation II)

[0284] Where CX represents any one of the following groups: aldehyde group (-CHO), ketone group (-CO-), ester group (-C(O)O-), and cyano group (-CN).

[0285] Implementation Scheme 35: According to any one of Implementation Schemes 24 to 34, it further includes one or more solvents.

[0286] Implementation Scheme 36: According to the implementation scheme of Implementation Scheme 35, one or more solvents include ethanol.

[0287] Implementation Scheme 37: According to the implementation scheme of Implementation Scheme 35, one or more solvents include: (A) alcohols other than ethanol, (B) esters, (C) ketones, (D) ethers, (E) aliphatic solvents, (F) aromatic solvents, (G) alkylated aromatic solvents, or (H) combinations thereof.

[0288] Implementation Scheme 38: According to the implementation scheme of Implementation Scheme 35, one or more solvents further include butyl acetate, isobutanol, or combinations thereof.

[0289] Implementation Scheme 39: According to any one of Implementation Schemes 24 to 38, wherein after mixing the components of the composition, the resulting mixture has a pot life of 2 hours or longer at 25°C.

[0290] Implementation Scheme 40: An embodiment according to any one of Implementation Schemes 24 to 39, wherein the Michael addition curing composition is cured in the range of 20°C to 27°C.

[0291] Implementation Scheme 41: According to any one of Implementation Schemes 24 to 40, wherein the Michael addition curing composition is cured in a range of 20°C to 27°C for 7 days or less.

[0292] Implementation Scheme 42: According to any one of Implementation Schemes 24 to 41, wherein at least one metal oxide comprises magnesium oxide, aluminum oxide, metal silicates, and combinations thereof.

[0293] Implementation Scheme 43: According to any one of Implementation Schemes 23 to 42, the at least one metal salt comprises one or more of metal carbonates and metal silicates selected from sodium carbonate, calcium carbonate, calcium silicate, sodium aluminum silicate, magnesium aluminum silicate, and combinations thereof.

[0294] Embodiment 44: A coating composition comprising the composition according to any one of embodiments 24 to 43.

[0295] Implementation Scheme 45: According to the embodiment of Implementation Scheme 44, the coating composition is applied with a wet coating thickness of 100 micrometers and dried for 24 hours to form a cured coating, and wherein the cured coating exhibits a pendulum impact hardness of about 5 or greater, as measured by ASTM D-4366.

[0296] Implementation Scheme 46: A coated article comprising: 1) a substrate having at least one main surface; and 2) a cured coating formed by the coating composition according to claim 44, the cured coating being applied directly or indirectly at least partially to at least one main surface.

[0297] Implementation Scheme 47: According to the implementation scheme of Implementation Scheme 46, the substrate includes wood, metal, plastic, ceramic, cement board or any combination thereof.

[0298] All patents, patent applications, and publications cited herein, including their full disclosures and electronically available materials, are incorporated herein by reference. The foregoing detailed descriptions and embodiments are given solely for clarity of understanding. It should be understood that no unnecessary limitations are intended. The disclosure herein is not limited to the exact details shown and described; variations that will be apparent to those skilled in the art will be included within the scope of what is set forth herein and defined by the claims. In some embodiments, the disclosure herein may be practiced in the absence of any elements not specifically disclosed herein.

Claims

1. A Michael addition-curable composition comprising: A) It can provide at least one reactive donor for two or more nucleophilic carbanions; B) At least one reactive acceptor containing two carbon-carbon double bonds; C) A catalyst for catalyzing the Michael addition crosslinking reaction between the at least one reactive donor and the at least one reactive acceptor; and D) A co-catalyst containing at least one metal oxide. The catalyst comprises at least one quaternary salt having the following structural formula I. R 1 R 2 R 3 R 4 M + X - (Formula I) In the above formula, R 1 R 2 R 3 and R 4 Each is independently selected from C1-C12 alkyl, C6-C14 aryl, C7-C15 alkylaryl, C7-C15 aralkyl, and any combination thereof, or R 1 R 2 R 3 and R 4 Any two of them, together with the M atoms to which they are attached, form a heterocycle; M is selected from N or P; and X - Derived from hydrofluoric acid; The metal oxide is magnesium oxide; and The at least one reactive donor includes a reactive donor having an epoxy resin-based backbone; and The at least one reactive receptor contains a carbon-carbon double bond having a structure of C=CC(O)O-.

2. The Michael addition-curable composition according to claim 1, wherein the at least one reactive donor comprises two or more acidic protons CH from an activated methylene group, a methine group, or a combination thereof.

3. The Michael addition-curable composition according to claim 2, wherein the two or more acidic protons CH of the activated methylene group, methine group, or combination thereof are derived from acetoacetate or malonate compounds.

4. The Michael addition-curable composition according to claim 1, wherein the at least one reactive donor comprises at least one reactive diluent obtained by transesterification of at least one diol or at least one polyol.

5. The Michael addition-curable composition according to claim 1 further comprises ethanol.

6. The Michael addition-curable composition according to claim 1, further comprising: (A) alcohols other than ethanol, (B) esters, (C) ketones, (D) ethers, (E) aliphatic solvents, (F) aromatic solvents, (G) alkylated aromatic solvents, or (H) combinations thereof.

7. The Michael addition-curable composition according to claim 1, wherein M is selected from N.

8. A coating composition comprising the Michael addition-curing composition according to claim 1.

9. A coated article, comprising: A substrate having at least one main surface; and A cured coating formed from the coating composition according to claim 8, the cured coating being applied directly or indirectly at least partially to the at least one main surface; The substrate may include wood, metal, plastic, ceramic, cement board, or any combination thereof.

Images