Curable composition comprising a polythiol

Abstract

The present disclosure describes a curable composition comprising: (a) an epoxy-containing compound; (b) a polythiol curing agent comprising at least three sulfhydryl moieties, wherein the polythiol comprises a cyclic (hetero)carbonaceous ring structure containing 0 to 4 nitrogen atoms and from 3 to 15 carbon atoms, optionally substituted by from one to four pendant groups containing from 1 to 4 carbon atoms and optionally containing at least one of the sulfhydryl moieties; and (c) a curing enhancement catalyst, wherein the curable composition typically comprises a molar ratio of epoxy moieties to sulfhydryl moieties from about 0.95:1 to about 2.0:1. In some embodiments, at least three of the sulfhydryl moieties in the polythiol curing agent are secondary thiol groups, and / or the polythiol curing agent may comprise no nitrogen or oxygen atoms. Kits comprising the curable composition, as well as desirable characteristics of a cured composition are also described herein.

Description

CURABLE COMPOSITION COMPRISING A POLYTHIOLFIELD

[0001] The present disclosure describes a curable composition comprising: (a) an epoxycontaining compound; (b) a polythiol curing agent comprising at least three sulfhydryl moieties; and (c) a curing enhancement catalyst. In some embodiments, at least three of the sulfhydryl moieties in the polythiol curing agent are secondary thiol groups, and / or the polythiol curing agent comprises no nitrogen or oxygen atoms. Kits comprising the curable composition in at least two vessels, as well as desirable characteristics of cured compositions, are also described herein. Also described herein are methods of making cured compositions, comprising curing the curable composition, and the use of such cured compositions as an adhesive, an ink, a coloring system, a paint, a 3D printing resin, a thermosetting resin (and / or composite), a sealant, a coating, or a dental resin, among other potential applications.BACKGROUND

[0002] Thiol- / Mercaptan- / Sulfhydryl- containing compounds are generally known as curing agents, but the impact of their chemistries on applications in epoxy-curable formulations / systems is not universally known or discussed in public disclosures, some of which are enumerated below.

[0003] U.S. Patent No. 3,676,440 discloses trithiols comprising the tris(3-mercaptopropionate) ester of tris(2-hydroxyethyl)isocyanurate, but more generally high polarity tri-mercapto-functional isocyanurates, which are purported to be useful as curing agents in curable liquid polymer systems containing polyenes and a free-radical initiator.

[0004] U.S. Patent No. 4,266,055 discloses tris(3-acetylthiopropyl)isocyanurate compounds as an intermediate in the preparation of tris(3-mercaptopropyl)isocyanurate compounds, which are useful as polymerization reaction regulators, crosslinking agents, curing agents, lubricant adjuncts, etc.

[0005] Japanese Patent Publication No. JP 2012153794A very broadly discloses thiol compounds having cyclic structures, specifically l,4-bis(mercaptomethyl)benzene, for improved water esistance in curable systems.

[0006] PCT Publication No. WO 2015 / 060439 discloses what is called a “one-component” thermosetting composition having both low-temperature curability and maintenance of adhesivestrength, although the composition contains both an aromatic epoxy component and a tris(3- mercaptopropyl)isocyanurate component.

[0007] Japanese Patent No. JP 6983380 also discloses a “one-component” resin epoxy-resin composition that uses a curing agent combination of a non-ester-containing dithiol and a non-ester- containing polythiol.

[0008] PCT Publication No. WO 2018 / 159564 discloses glass-flake-filled epoxy resin compositions incorporating a polythiol. Such compositions are disclosed as having low viscosity, high fluidity, and excellent shelf-life and low-temperature curability.

[0009] U.S. Patent No. 3,081,352 discloses cyclic mercapto-derivative vulcanization agents, specifically including mono-mercapto-cyclododecadiene and di-mercapto-cyclododecene made by reacting cyclododecatriene with thioacetic acid. Because the cyclic unsaturations are disclosed to make the final vulcanized product less susceptible to ozone degradation / rupture, the patent teaches the undesirability of full reaction of the cyclic unsaturations to form tri-mercapto- cyclododecanes.

[0010] U.S. Patent No. 8,461,293 discloses polythiol compositions derived from mercaptanization of olefinic hydrocarbons such as cyclooctadiene, cyclododecatriene, and trivinylcyclohexane, as well as their utility as curing agents in adhesive and other applications.

[0011] U.S. Patent No. 10,189,779 discloses processes for producing thiol / sulfide compounds from olefins, which processes focus on using diphenylamine and / or phenolic compounds to replace phosphite scavengers that are difficult to separate out from desired products.

[0012] There remains a need to improve curable formulations, for example in thermosetting and / or epoxy-containing resins. There is also a need to improve the curing agent + curing enhancement catalyst component combination, possibly in combination with the breadth of all resin compounds or with one or two of the most common resin compounds. The present disclosure identifies not only individual components of curable compositions, but their combination and the unexpected performance characteristics that can be simultaneously attained in a cured system.SUMMARY

[0013] The present disclosure provides curable composition comprising: (a) an epoxy-containing compound; (b) a polythiol curing agent comprising at least three sulfhydryl moieties; and (c) a curing enhancement catalyst. In advantageous embodiments, the curable composition cancomprise a molar ratio of epoxy moieties to sulfhydryl moieties from about 0.95: 1 to about 2.0: 1. Additionally or alternatively, the polythiol can comprise a cyclic (hetero)carbonaceous ring structure containing 0 to 4 nitrogen atoms and from 3 to 15 carbon atoms, optionally substituted by from one to four pendant groups containing from 1 to 4 carbon atoms and optionally containing at least one of the sulfhydryl moieties.

[0014] In a particular embodiment, at least three of the sulfhydryl moieties in the polythiol curing agent are secondary thiol groups. In an additional or alternative particular embodiment, the polythiol curing agent may comprises no nitrogen or oxygen atoms.

[0015] When cured, the composition can exhibit one or more, two or more, three or more, four or more, or all five of the following characteristics: (i) a glass transition temperature (Tg) of at least 115°C; (ii) a lap shear strength of at least 600 psi; (iii) a shore D hardness of at least 77.0; (iv) in a solvent resistance test, a weight change when exposed to water, 10 wt% aqueous HC1, and / or 10wt% aqueous NaOH of 0.25% or less; and (v) in a solvent resistance test, at least two, at least three, at least four, or all five of the following (which collectively count as one with respect to the alphanumeric (v)): a dimensional change of 0.20% or less when exposed to distilled water; a dimensional change of 0.40% or less when exposed to 10 wt% aqueous HC1; a dimensional change of 0.50% or less when exposed to 10 wt% aqueous NaOH; a dimensional change of 1.0% or less when exposed to methyl ethyl ketone; and a dimensional change of 0.25% or less when exposed to toluene.

[0016] In some embodiments, the polythiol curing agent can comprise a trimercapto-C7-C16- cycloalkane, a tetramercapto-C7-C16-cycloalkane, a l,3,5-tris(mercapto-Cl-C4-alkyl)-l,3,5- triazine-2, 4, 6-trione, a pentaerythritol tetrakis(mercapto-Cl-C6-alkanoate ester), a tri-Cl-C4- alkylol-C2-C6-alkane tris(mercapto-C2-C6 alkanoate ester), or a combination thereof, and in particular can comprise trimercaptocyclododecane. The polythiol curing agent can be present in an amount from 3.0% to 40%, based on a total weight of the composition.

[0017] In some embodiments, the curing enhancement catalyst can comprise an oxygencontaining amine, examples of which can include nitroguanidine, an N,N-di-Cl-C4-alkyl-C2-C6- alkanolamine, a bis(di-Cl-C4-alkylamino-C2-C6-alkyl)ether, a di-Cl-C4-alkylamino-C2-C6- alkoxy-C2-C6-alkanol, a (di-C 1 -C4-alkylamino-C2-C6-alkoxy)-C2-C6-alkylamino-C2-C6- alkanol, (bis(di-Cl-C4-alkylamino)-C2-C6-alkyl)amino-C2-C6-alkanol, morpholine, an N-Cl- C6-alkylmorpholine, a dimorpholino-di-Cl-C6-alkylether, an N-Cl-C6-alkylmorpholine,imidazole, an N-Cl-C6-alkylimidazole, a l,2-di-Cl-C4-alkylimidazole, a dimercapto-dioxa-C7- C12-alkane, a tris(di-Cl-C4-alkylamino-C2-C6-alkyl)-hydroxy-C6-C14-aromatene, a C2-C6- alkyl,bis(di-C 1 -C4-alkylamino-C2-C6-alkyl)-hydroxy-C6-C 14-aromatene, a bis(di-C 1 -C4- alkylamino-C2-C6-alkyl)-dihydroxy-C6-C14-aromatene, or a combination thereof.

[0018] Additionally or alternatively, the curing enhancement catalyst can comprise a non-oxygen- containing carbonaceous amine, examples of which can include a tetra-Cl-ClO-alkylguanidine, a penta-Cl-C5-alkylguanidine, a diazabicyclo-C7-C12-alkane, a diazabicyclo-C7-C12-alkene, a tri- C2-C12-alkylamine, a tri-C2-C12-alkyamine, a di-Cl-C6-alkyl-cyclo-C5-C12-alkylamine, penta- C 1 -C4-alkyl-di-C2-C4-alkylenetriamine, tetra-C 1 -C4-alkyl-C2-C4-alkylenediamine, di-C2-C6- alkylpiperazine, or a combination thereof. The curing enhancement catalyst can be present in an amount from 0.1% to 20%, based on a total weight of the composition.

[0019] In some embodiments, the epoxy-containing compound can comprise a polyglycidyl ether of bisphenol A, a polyglycidyl ether of bisphenol F, a polyglycidyl ether of bisphenol AF, a polyglycidyl ether of bisphenol B, a polyglycidyl ether of bisphenol C, a polyglycidyl ether of bisphenol S, a polyglycidyl ether of bisphenol Z, a polyglycidyl ether of bisphenol TMC, a polyglycidyl ether of a biphenyl polyalcohol, a polyglycidyl ether of a binaphthol, a polyglycidyl ether of a polyhydroxy naphthalene, a polyglycidyl ether of a polyhydroxy benzene, a polyglycidyl ether of a hydroxy(Cl-C4 alkyl) phenol, a polyglycidyl ether of a poly[hydroxy(Cl-C4 alkyl)] benzene, a halogenated version thereof, a reaction product thereof with an extender to form an epoxy-adduct, or a combination thereof. Additionally or alternatively, the epoxy-containing compound: (a) is at least partially aromatic; (b) comprises substantially no nitrogen; (c) is at least 90% difunctional, based on the total weight of all epoxy-containing compounds; (d) satisfies two of (a), (b), and (c); or (e) satisfies all of (a), (b), and (c). The epoxy-containing compound can be present in an amount from 10% to 85%, based on a total weight of the composition.

[0020] In some (many) embodiments, the composition can further comprise an organic solvent, an antioxidant, a pH adjuster, a colorant, a dye, a pigment, a decolorizer, a deodorant, a dispersant (wetting agent), a toughener, a thixotropic agent, a matting agent, a wax, a filler, a non-nitrogen- containing curing agent, or a combination thereof.

[0021] The present disclosure also describes a kit, which can comprise the curable composition disclosed herein, which kit comprises at least two vessels adapted to be in fluid communication with each other. The at least epoxy-containing compound (a) is present in one of the at least twovessels but isolated from curing enhancement catalyst (c) in at least another of the at least two vessels, so as to not allow contact and / or chemical reaction between components (a) and (c) until desired. In some embodiments, at least a portion of polythiol curing agent (b) is optionally present in the same vessel as curing enhancement catalyst (c).

[0022] The present disclosure also describes a method of forming a cured composition comprising: providing the kit disclosed herein and / or providing the curable composition disclosed herein as disposed in at least two vessels; and allowing the components from the kit isolated in the at least two vessels and / or the components in the disclosed curable composition disposed in the at least two vessels to fluidly contact each other outside said vessels, at a temperature sufficient to achieve substantial curing, such as within 15 minutes, to thereby form the cured composition. The cured composition so formed by this method can comprise or represent at least a portion of an adhesive, an ink, a coloring system, a paint, a 3D printing resin, a thermosetting resin (and / or composite), a sealant, a coating, or a dental resin.

[0023] In advantageous embodiments, wherein the method can result in cured composition that exhibit one or more, two or more, three or more, four or more, or all five of the following: (i) a glass transition temperature (Tg) of at least 115°C; (ii) a lap shear strength of at least 600 psi; (iii) a shore D hardness of at least 77.0; (iv) in a solvent resistance test, a weight change when exposed to water, 10 wt% aqueous HC1, and / or 10 wt% aqueous NaOH of 0.25% or less; and (v) in a solvent resistance test, at least two, at least three, at least four, or all five of the following (which collectively count as one with respect to the alphanumeric (v)): a dimensional change of 0.20% or less when exposed to water; a dimensional change of 0.40% or less when exposed to 10 wt% aqueous HC1; a dimensional change of 0.50% or less when exposed to 10 wt% aqueous NaOH; a dimensional change of 1.0% or less when exposed to methyl ethyl ketone; and a dimensional change of 0.25% or less when exposed to toluene.BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The Drawings / Figures associated with this description are meant to supplement and / or illustrate, but not necessarily to limit, selected aspects of the Examples and / or the invention described herein, in association with the description text. Elements pictured therein may not be to scale generally, nor with respect to other elements pictured in the Figures.

[0025] Figure 1 shows a visual representation of different volume ratio cartridges, empty and filled, as well as their assembly into a dispenser or applicator (kit) for mixing and application, e.g., as an adhesive (but in this case for testing of formulations as Examples and Comparative Examples).

[0026] Figure 2 shows an example of lap shear strength sample preparation. Top view and side view show the application of a formulation atop a nonstick tape covering a cold-rolled steel plate. An alternative sample preparation (not shown) is where the ~0.5” offset buffer / gap at the upper edge of the coated plate is removed, such that the -0.5” formulation casting is at the very top of the plate. Curing sample shows a considerable weight being applied to encourage sample thickness uniformity.DETAILED DESCRIPTION

[0027] As used herein, a range of values referencing real numbers [A] and [B], expressed as “between [A] and [B]”, should be understood as including [A] and [B] unless otherwise specified for either / both of [A] and [B], the same as if the range were expressed as “from [A] to [B]” or “at least [A]” or “up to [B]”.

[0028] Any description herein, even if described in relation to one or some specific embodiment(s), should be understood to be applicable to and interchangeable with other embodiments described or contemplated herein, to the extent that such application and / or interchangeability is not inoperable or specifically precluded.Definitions

[0029] As used herein, the range “C[m]-C[p]”, with [m] and [p] as non-zero numbers (typically integers, unless meant to subsume an average, in context), should be understood to refer to a number of carbon atoms “from C[m] to C[p]”, including the endpoints, such as in a specific moiety or chemical substitution containing carbon atoms. For example, a “C1-C4” alkyl is an alkyl comprising from 1 to 4 carbon atoms.

[0030] As used herein, the term “alkyl” should be understood to mean a monovalent saturated linear, branched, or cyclic (in some cases, linear or branched but acyclic) hydrocarbon moiety of formula -CnH2n+l wherein n is an integer from 1 to 100, such as from 1 to 75, from 1 to 50, from 1 to 25, from 1 to 18, or from 1 to 12. Non-limiting examples of alkyl groups can include, but arenot necessarily limited to, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, amyl, 2-methylbutyl, 2,2-dimethylpropyl, cyclopentyl, hexyl, 2-methylpentyl, 2,2- dimethylbutyl, 2,3 -dimethylbutyl, cyclohexyl, methyl cyclopentyl, cyclopentylmethyl, heptyl, 2- ethylhexyl, cycloheptyl, methylcyclohexyl, cyclohexylmethyl, dimethylcyclopentyl, methylcylopentylmethyl, ethylcyclopentyl, cyclopentylethyl, norbomane (bicyclo[2.2.1]heptane), octyl, cyclooctyl, 2-ethylhexyl, decyl, cyclodecyl, dodecyl, cyclododecyl, tetradecyl, cyclotetradecyl, and the like, as well as mixtures thereof.

[0031] As used herein, the terms “alkylene” and “alkylenyl” should be understood to interchangeably refer to a divalent saturated linear, branched, or cyclic (in some cases, linear or branched but acyclic) hydrocarbon moiety of formula -CnH2n-, wherein n is an integer from 1 to 100, such as from 1 to 75, from 1 to 50, from 1 to 25, from 1 to 18, or from 1 to 12. Non-limiting examples of alkylene(yl) groups can include, but are not necessarily limited to, methylene(yl), ethylene(yl), propylene(yl), isopropylene(yl), butylene(yl), isobutylene(yl), methylpropylene(yl), pentylene(yl), 2-methylbutyl ene(yl), 2,2-dimethylpropylene(yl), cyclopentylene(yl), hexylene(yl), 2-methylpentylene(yl), 2,2-dimethylbutylene(yl), 2,3-dimethylbutylene(yl), cyclohexylene(yl), methylcyclopentylene(yl), cyclopentylmethylene(yl), heptylene(yl), 2-ethylhexylene(yl), cycloheptylene(yl), methylcyclohexylene(yl), cyclohexylmethylene(yl), dimethylcyclopentylene(yl), methylcylopentylmethylene(yl), ethylcyclopentylene(yl), cyclopentylethylene(yl), norbomylene(yl), and the like, as well as mixtures thereof. In certain cases, based on their divalent nature, alkylenyl moieties can be attached to two separate moieties to link them or may be attached, directly or indirectly to a single moiety to form a cyclic compound.

[0032] As used herein, the term “aliphatic” should be understood to refer to a linear or branched, saturated or unsaturated, cyclic or acyclic but non-aromatic hydrocarbon compound or moiety. Optionally, aliphatic compounds or moieties may be substituted with one or more nonhydrocarbon functional groups, such as, but not limited to, hydroxyl (-OH), monosubstituted ether (-O-R’), disubstituted ether (-O-), sulfhydryl (-SH), monosubstituted thioether (-S-R’), disubstituted thioether (-S-), halogen (-Br, -Cl, -F, and / or -I), aldehyde (-C(=O)-H), monosubstituted ketone (-C(=O)-R’), disubstituted ketone (-C(=O)-), carboxylic acid (-COOH), monosubstituted carboxylate ester (-COOR’), disubstituted carboxylate ester (-C(=O)-O-), monosubstituted anhydride (-C(=O)-O-C(=O)-R’), disubstituted anhydride (-C(=O)-O-C(=O)-), monosubstituted carbonate (-O-C(=O)-O-R’), disubstituted carbonate (-O-C(=O)-O-),monosubstituted amine (-NR’2), monosubstituted imine (-N=R’), divalent amine (>N-R’), disubstituted amide (-N(R’)-C(=O)-), monosubstituted amide (-C(=O)-NR’2), disubstituted urethane (-NR’-C(=O)-O-), monosubstituted urea (-NR’-C(=0)-NR’2), disubstituted urea (-NR’- C(=O)-NR’-), monosubstituted organosilane (-SiR’3), disubstituted organosilane (-SiR’2-), and mixtures thereof, each R’ being independently hydrogen or a Cl -Cl 2 alkyl, such as a C1-C6 alkyl (however, it should be understood that the R’ in each of the monosubstituted ether, monosubstituted thioether, monosubstituted ketone, and monosubstituted carboxylate ester cannot be hydrogen, lest they devolve into the hydroxyl, sulfhydryl, aldehyde, and carboxylic acid, respectively).

[0033] As used herein, the terms “aromatic” and “aryl” should be understood to interchangeably refer to a compound or a moiety comprising at least one aromatic ring (z.e., a ring respecting Hiickel’s aromaticity rule, such as a phenyl, naphthalenyl, anthracenyl, phenanthrenyl, phenalenyl, chrysenyl, pyrenyl, benzanthracenyl, triphenylenyl, and the like), in particular containing one, two or three aromatic rings (typically but not necessarily connected aromatically to each other), preferably containing one or two aromatic rings (typically but not necessarily connected aromatically to each other). Araliphatic and / or aralkyl compounds, groups or linkers (z.e., comprising both an aromatic moiety and a non-aromatic moiety) are encompassed by the term “aromatic”. Such “aromatic” compounds need not be strictly hydrocarbons, as heteroatoms within ring structures still allow for aromaticity (e.g., pyridinyl, pyrazinyl, traizinyl, quinolinyl, isoquionlinyl, quinoxalinyl (benzopyrazinyl), phenanthrolinyl, acridinyl, benzoquinolinyl, phenanthridinyl, phenazonyl, naphthoquinolinyl, benzacridinyl, and the like), and functional groups containing heteroatoms, such as but not limited to those enumerated in the definition of “aliphatic,” may additionally or alternatively be present (or one or both kinds of heteroatoms may be absent, as desired).

[0034] As used herein, and unless otherwise specifically defined herein, the prefix “poly”, when used in reference to functional groups on a moiety but pointedly not in reference to repeat units and / or polymers / oligomers, should be understood to mean containing two or more such functional groups. For example, a polythiol should be understood to mean a compound having two or more thiol / sulfhydryl (mercaptan) functional groups attached thereto, and a polyglycidyl ether should be understood to mean a compound having at least two glycidyl ether (1,2-epoxy, or oxirane) moieties.

[0035] In the context of the present invention, the term “organic solvent” should be understood to include any solvent comprising one or more carbon atoms (carbonaceous). However, it should be understood that water, by itself or in combination with a carbonaceous solvent, is also considered “organic” herein, although mineral acids and bases, even in combination with water but with substantially no carbonaceous solvent (e.g., aqueous HC1, aqueous NaOH, and the like), are considered “inorganic” herein. Mineral acids / bases or other inorganic compounds present at impurity levels in water are unsatisfactory to make water inorganic.Curable Composition

[0036] The present disclosure describes a curable composition including (a) an epoxy-containing compound, (b) a polythiol curing agent (a.k.a. hardener), and (c) optionally but preferably a curing enhancement catalyst.Epoxy-Containing Compound

[0037] Epoxy-containing compounds (a) herein can include those containing 1,2-, 1,3-, or 1,4- cyclic rings, typically constrained, containing an ether oxygen linkage within the ring. Although epoxy-containing compounds useful herein typically have some aromatic character, it is possible (though not usually preferred) for the epoxy-containing compound (a) to be entirely non-aromatic (aliphatic). In preferred embodiments, epoxy-containing compounds useful for curable compositions herein can comprise or be polyepoxy compounds, in particular predominantly (more than 50%, based on the total weight of all epoxy-containing compounds) diepoxides. Nevertheless, in some embodiments and / or for certain applications, it may be advantageous for a portion of the epoxy-containing compounds to be monoepoxy compounds. When present, the amount and character of the monoepoxy compounds should not be so great as to frustrate or prevent appropriate levels of hardening / curing of the curable compositions herein. Non-limiting examples of epoxy-containing compounds (a) can include, but are not necessarily limited to, a polyglycidyl ether of bisphenol A, a polyglycidyl ether of bisphenol F, a polyglycidyl ether of bisphenol AF, a polyglycidyl ether of bisphenol B, a polyglycidyl ether of bisphenol C, a polyglycidyl ether of bisphenol S, a polyglycidyl ether of bisphenol Z, a polyglycidyl ether of bisphenol TMC, a polyglycidyl ether of a biphenyl polyalcohol, a polyglycidyl ether of a binaphthol, a polyglycidyl ether of a polyhydroxy naphthalene, a polyglycidyl ether of apolyhydroxy benzene, a polyglycidyl ether of a hydroxy(Cl-C4 alkyl) phenol, a polyglycidyl ether of a poly[hydroxy(Cl-C4 alkyl)] benzene, a halogenated (e.g., brominated, fluorinated, etc.) version thereof, a polyepoxidized phenolic (including but not limited to those based on phenol, chlorophenol, allylphenol, cresol, resorcinol, bisphenol A, bisphenol F, pyrogallol, hydroxy quinol, phloroglucinol, or the like, or combinations thereof) novolac resin / precursor, a polyepoxidized aminophenolic novolac, a poly epoxidized monoaminobenzene, a poly epoxidized diaminobenzene, cyclopentene oxide; cyclohexene oxide; cycloheptene oxide; cyclooctene oxide; norbornene oxide; dicyclopentadiene oxide; dicyclopentadiene dioxide; cyclic terpene oxides such as terpineol oxide, alpha-ionone oxide, limonene oxide, terpinene oxide, alpha-pinene oxide, menthadiene oxide, and mixtures thereof, as well as (typically partial) reaction products thereof with extenders to increase initial viscosity / molecular weight, such as forming epoxy-adducts (non-limiting examples of such extenders potentially including, but not necessarily limited to, epichlorohydrin, polyols having a number average molecular weight (Mn) less than 3000 g / mol, in particular about 2000 g / mol or less, about 1000 g / mol or less, about 500 g / mol or less, or about 250 g / mol or less, poly carboxylic acids having a number average molecular weight (Mn) less than 3000 g / mol, in particular about 2000 g / mol or less, about 1000 g / mol or less, about 500 g / mol or less, or about 250 g / mol or less, polyorganosilanols having a number average molecular weight (Mn) less than 2000 g / mol, in particular about 1000 g / mol or less, about 700 g / mol or less, about 400 g / mol or less, or about 250 g / mol or less, or the like, or combinations thereof). In some embodiments, the epoxy-containing compound is at least partially aromatic, comprises substantially no nitrogen, or is at least 95% difunctional, based on the total weight of all epoxy-containing compounds, or two of these, or all three of these.

[0038] In most embodiments, the epoxy-containing compound can be present in the curable composition in an amount from 8.0% to 90%, in particular from 10% to 85%, from 12% to 80%, or from 15% to 70%, based on a total weight of the curable composition.Polythiol Curing Agent

[0039] Non-limiting examples of polythiol curing agents can include, but are not necessarily limited to, a trimercapto-C7-C16-cycloalkane (in particular, trimercaptocyclododecane), a tetramercapto-C7-C16-cycloalkane, a 1, 3, 5-tris(mercapto-Cl-C4-alkyl)-l, 3, 5-triazine-2, 4,6- trione (in particular, mercaptopropyl), a pentaerythritol tetrakis(mercapto-Cl-C6-alkanoate ester)(in particular, mercaptopropionate and / or mercaptobutylate), a tri-Cl-C4-alkylol-C2-C6-alkane tris(mercapto-C2-C6 alkanoate ester) (in particular, trimethylolpropane tris(mercaptopropionate)), or a combination thereof. The polythiol curing agent may additionally or alternatively comprise a cyclic (hetero)carbonaceous ring structure containing 0 to 4 nitrogen atoms and from 3 to 15 carbon atoms, optionally substituted by from one to four pendant groups containing from 1 to 4 carbon atoms and optionally containing at least one of the sulfhydryl moieties. In some advantageous embodiments, at least three of the sulfhydryl moieties in the polythiol curing agent (b) can be secondary thiol groups. In additional or alternative advantageous embodiments, the polythiol curing agent (b) can comprise no nitrogen atoms, no oxygen atoms, or both (in particular, neither nitrogen nor oxygen atoms). A particular polythiol curing agent comprises or is trimercaptocyclododecane.

[0040] In some embodiments, the polythiol curing agent described herein may be prepared using methods that are readily available or commonly employed in the field. Reference may notably be made to the process described in co-pending patent application filed at the French Patent Office on March 31, 2023, under application number FR2303201 or in GB1352527 filed by Ciba Geigy, the contents of which are hereby incorporated by reference in their entirety.

[0041] In most embodiments, the polythiol curing agent can be present in the curable composition in an amount from 2.5% to 45%, in particular from 3.0% to 40% or from 4.0 to 36%, based on a total weight of the curable composition.Curing Enhancement Catalyst

[0042] The curing enhancement catalyst (c) can comprise an oxygen-containing amine, a non- oxygen-containing carbonaceous amine, a phosphonium salt, a phosphine, or a mixture thereof. Non-limiting examples of oxygen-containing amines can include, but are not necessarily limited to, nitroguanidine, an N,N-di-Cl-C4-alkyl-C2-C6-alkanolamine, a bis(di-Cl-C4-alkylamino-C2- C6-alkyl)ether, a di-Cl-C4-alkylamino-C2-C6-alkoxy-C2-C6-alkanol, a (di-Cl-C4-alkylamino- C2-C6-alkoxy)-C2-C6-alkylamino-C2-C6-alkanol, (bis(di-Cl-C4-alkylamino)-C2-C6- alkyl)amino-C2-C6-alkanol, morpholine, an N-Cl-C6-alkylmorpholine, a dimorpholino-di-Cl- C6-alkylether, anN-Cl-C6-alkylmorpholine, imidazole, anN-Cl-C6-alkylimidazole, a 1,2-di-Cl - C4-alkylimidazole, a dimercapto-dioxa-C7-C12-alkane (in particular, l,8-dimercapto-3,6- dioxaoctane), a tris(di-Cl-C4-alkylamino-C2-C6-alkyl)-hydroxy-C6-C14-aromatene, a C2-C6-alky 1 ,bi s(di -C 1 -C4-alkylamino-C2-C6-alkyl)-hydroxy-C6-C 14-aromatene, a bis(di-C 1 -C4- alkylamino-C2-C6-alkyl)-dihydroxy-C6-C14-aromatene, or a combination thereof. Non-limiting examples of non-oxygen-containing carbonaceous amines can include, but are not necessarily limited to, atetra-Cl-ClO-alkylguanidine, a penta-Cl-C5-alkylguanidine, a diazabicyclo-C7-C12- alkane (in particular, l,4-diazabicyclo[2.2.2]octane), a diazabicyclo-C7-C12-alkene (in particular, l,8-diazabicyclo[5.4.0]undec-7-ene), a tri-(C5-C16-aryl)amine, a tri-(C2-C12-alkyl)amine, a trial -Cl 6-hydrocarbyl)amine, a di-Cl-C6-alkyl-cyclo-C5-C12-alkylamine, penta-Cl-C4-alkyl-di- C2-C4-alkylenetriamine, tetra-C 1 -C4-alkyl-C2-C4-alkylenediamine, di-C2-C6-alkylpiperazine, or a combination thereof.

[0043] In most embodiments, the curing enhancement catalyst can be present in the curable composition in an amount from 0.07% to 25%, in particular from 0.1% to 20% from 0.5% to 18%, from 1.0% to 15%, or from 3.0% to 12%, based on a total weight of the curable composition.Curable / Cured Composition Characteristics

[0044] In advantageous embodiments, the curable compositions according to the present disclosure can be additionally defined by a molar ratio of epoxy moieties to sulfhydryl moieties (curing stoichiometry) from about 0.90: 1 to about 2.1 : 1, such as from about 0.95: 1 to about 2.0: 1, from about 0.99: 1 to about 1.97: 1, from about 1.0: 1 to about 1.9: 1, from about 1.05: 1 to about 1.85:1, from about 1.1 : 1 to about 1.8: 1, from about 1.15: 1 to about 1.7: 1, from about 1.2: 1 to about 1.65:1, from about 1.1 : 1 to about 1.60: 1, from about 1.15: 1 to about 1.55: 1, from about 1.15:1 to about 1.8: 1, from about 1.2: 1 to about 1.75: 1, from about 1.25: 1 to about 1.75: 1, or from about 1.3:1 to about 1.7: 1 (in particular, from about 0.95: 1 to about 2.0: 1, from about 1.1 : 1 to about 1.8:1, from about 1.2: 1 to about 1.65: 1, from about 1.1 :1 to about 1.60: 1, or from about 1.25: 1 to about 1.75: 1).

[0045] The curable composition can be cured (or hardened). Those skilled in the art should understand that the term “cured,” particularly in the case of thermosetting liquid compositions having a viscosity to enable reasonable handling and / or when a component having epoxyfunctionality is involved, usually indicates attainment of solid character (extremely high viscosity, or effective solidification), due to reaction of curable composition components, typically via chemical (and / or physical) crosslinks, whether based on the curable composition components alone or in combination with external components, additives, and / or impact (such as applicationof pressure / energy to facilitate or cause reaction). Nevertheless, technically, some level of curing / hardening can occur without solidification / crosslinking, but a practical application of the term “cured” typically still involves at least a doubling of, preferably at least a quintupling of or an order of magnitude (-10 times) increase in, initial (unreacted and / or based on a limited prereaction level) viscosity. It should be noted that effective solidification (e.g., crosslinking sufficient to impart substantially infinite viscosity) may still occur, such as in certain thermosetting systems, at undesirably low reaction extent (conversion), while, in other circumstances, reaction may be arrested by physico-chemical factors (such as polymeric glass transition temperature, relative to curing temperature, as well as kinetic reactive effects, inter alia), thereby severely limiting or preventing further reaction (conversion). Aside from judging the partiality or completeness of the curing process by visual and / or tactile observation, which can be somewhat subjective to the observer, one optional test of “sufficient” curing (a.k.a., gel time or gelation time) can represent the time it takes a dynamic mechanical analyzer (DMA) to resist -0.1% strain in time sweep oscillation mode while held at constant room temperature (~17-23°C). An alternative test of sufficient curing can be represented by a compositional weight loss of no more than 1% under thermogravimetric analysis (via TGA) while maintained at ~50°C constant temperature for at least 30 minutes.

[0046] Curing, such as in epoxy-based thermosetting systems, can advantageously occur in -5 minutes or less, such as in -3 minutes or less, in -1 minute or less, in -30 seconds or less, in -20 seconds or less, in -15 seconds or less, or in -10 seconds or less. Optionally in some applications, it can be practical for curing to take at least 1 second, or at least 3 seconds, so that the curable composition can be distributed into a desired shape or part form while still being liquid enough (having low enough viscosity) to enable manipulation.

[0047] In advantageous embodiments, the composition according to the present disclosure, when cured, can exhibit one, two, three, four, or all of the following: (i) a glass transition temperature (Tg) of at least 90°C, such as at least 95°C, at least 100°C, at least 105°C, at least 110°C, at least 115°C, or at least 120°C (in particular, at least 105°C, at least 115°C, or at least 120°C); (ii) a lap shear strength of at least 500 psi, such as at least 550 psi, at least 600 psi, at least 650 psi, at least 700 psi, at least 750 psi, or at least 800 psi (in particular, at least 550 psi, at least 600 psi, or at least 750 psi); (iii) a shore D hardness of at least 75.0, such as at least 76.0, at least 77.0, at least 78.0, at least 79.0, at least 80.0, or at least 81.0 (in particular, at least 76.0, at least 77.0, or atleast 80.0); (iv) in a solvent resistance test, a weight change when exposed to one, two, or all three of water, 10 wt% aqueous HC1, and 10wt% aqueous NaOH of 0.45% or less, such as 0.40% or less, 0.35% or less, 0.30% or less, 0.25% or less, 0.20% or less, or 0.15% or less (in particular, 0.40% or less, 0.35% or less, 0.30% or less, or 0.25% or less); and (v) in a solvent resistance test, at least one, at least two, at least three, at least four, or all of the following (in particular, at least three, at least four, or all) may be satisfied (satisfaction of whatever incarnation of the list within (v) counting as “one” with respect to the list of (i)-(v)): a dimensional change of 0.50% or less, such as 0.40% or less, 0.30% or less, 0.25% or less, 0.20% or less, 0.15% or less, 0.10% or less, or 0.05% or less, when exposed to distilled water (in particular, 0.50% or less, 0.25% or less, 0.20% or less, or 0.15% or less); a dimensional change of 0.50% or less, such as 0.40% or less, 0.30% or less, 0.20% or less, 0.10% or less, or 0.05% or less, when exposed to 10 wt% aqueous HC1 (in particular, 0.40% or less, 0.30% or less, or 0.20% or less); a dimensional change of 0.80% or less, such as 0.70% or less, 0.65% or less, 0.60% or less, 0.55% or less, 0.50% or less, 0.50% or less, 0.45% or less, 0.40% or less, 0.35% or less, or 0.30% or less, when exposed to 10 wt% aqueous NaOH (in particular, 0.80% or less, 0.65% or less, 0.50% or less, or 0.35% or less); a dimensional change of 3.0% or less, such as 2.5% or less, 2.0% or less, 1.5% or less, 1.2% or less, 1.1% or less, 1.0% or less, 0.9% or less, 0.8% or less, 0.7% or less, 0.6% or less, 0.5% or less, 0.4% or less, or 0.3% or less, when exposed to methyl ethyl ketone (in particular, 2.0% or less, 1.2% or less, 0.9% or less, 0.8% or less, or 0.5% or less); and a dimensional change of 0.65% or less, such as 0.60% or less, 0.55% or less, 0.50% or less, 0.45% or less, 0.35% or less, 0.25% or less, or 0.20% or less, when exposed to toluene (in particular, 0.65% or less, 0.45% or less, or 0.35% or less). As used herein, identification of a “[zz] wt% aqueous” solvent / component, where [zz] is a real number greater than 0 and less than 100, should be understood to mean a mixture / solution of ~[zz] wt% solvent / component and ~[100-zz] wt% of water (with allowance for impurities and / or other compounds within the water, such as salts, buffers, etc.).

[0048] Glass transition temperatures (Tg’ s) can be measured using an RDA III™ strain-controlled rotational rheometer, alternatively called a dynamic mechanical analyzer or DMA (commercially available from Anton Paar), running TA Instruments’ Orchestrator™ software, in torsion mode. Tg’s represent the average of at least two analyses.

[0049] Lap shear strength measurements were done according to ASTM DI 002, using an Instron 5500R™ mechanical tester running BlueHill v3.0 software. Opposing -1” x -4” (width x length) cold-rolled steel (CRS) plates (-0.06” thick) coated with nonstick (3M 5480™ PTFE) tape / film were cleaned with methyl ethyl ketone (MEK), sanded using -180 grit sandpaper, and cleaned again with MEK. Then samples of the curable compositions were applied to the upper portions of each plate in a -0.5” swath across the full 1” width between opposing plates to create an offset junction, and a -1.5 kg weight was applied thereacross (to approximate uniform adhesive thickness). Except as specifically noted herein, results represent an average of at least 5 samples (e.g., about 10 samples) tested.

[0050] Shore D hardness measurements were done according to ASTM D2240, using aPhase II Plus PHT-980 Shore D Durometer. Curable compositions were cured in a -45 mm x -65 mm silicone mold at ambient / room temperature (~17-23°C) for -1 week before sample measurement. Except as specifically noted herein, results represent an average of at least 5 points tested on each sample.

[0051] For solvent resistance tests, curable compositions are thoroughly mixed and cast into a -30 mm x -30 mm (length x width) silicone mold, with height determined by use of -4-5 grams of composition used (-10 mm, measured by caliper), and each sample is then cured at room temperature (-17-23) for at least -1 week. Samples are weighed and measured, then immersed (completely covered) in the solvent in a closed environment at room temperature (~17-23°C) for -1 week. The samples are then removed from the solvent, towel dried, and their dimensions and weight re-measured. Percent weight increase / decrease and percent dimensional increase / decrease (average of measurements in length and width dimensions only, not in height dimension) are calculated, said increases (positive numbers) may reflect solvent absorption / uptake and said decreases (negative numbers) may reflect solvent degradation and / or solublization of unreacted / lower molecular weight components, respectively.Solvents / Diluents

[0052] The curable composition of the present description may comprise one or more solvents / diluents (used interchangeably herein). The solvent(s) / diluent(s) can advantageously be non-reactive, organic, or both.

[0053] Suitable organic solvents can include, but are not limited to, primary and / or secondary alcohols (e.g., methanol, ethanol, propanol, isopropanol, cyclohexanol, benzyl alcohol, and the like), water (e.g., distilled, deionized, double distilled, double deionized, filtered, purified, or a combination thereof), butyl acetate, ethyl acetate, dioxane, methyl acetate, acetone, tert-butyl methyl ether, D-limonene, terpineol, geraniol, acetonitrile, dichloromethane, chloroform, dichloromethane, chlorobenzene, dichlorobenzene, tri chlorobenzene, difluorobenzene, tetrahydrofuran, dimethyl sulfoxide, dimethyl formamide, dimethylacetamide, dimethylformamide, N-methylpyrrolidone, anisole, morpholine, methyl ethyl ketone, toluene, xylene, benzene, mineral spirits, isoparaffins (such as commercially available under the tradename Isopar™ from ExxonMobil), glycol ethers (such as commercially available under the tradename Dowanol™ from Dow), and the like, and combinations thereof.

[0054] Advantageously, the curable composition of the present disclosure may be formulated to be substantially free of solvent or free of intentionally added solvent. For example, the curable composition of the present invention may contain little or no solvent, e.g., less than 10 wt%, less than 5 wt%, less than 1 wt%, less than 0.5 wt%, less than 0.1 wt%, or even about 0 wt%, based on the total weight of the curable composition.Additives

[0055] Additionally or alternatively vis-a-vis solvents / diluents above, the curable compositions of the present disclosure may optionally additionally comprise one or more additives, as desired, as necessary for short- or long- term stability, and / or as desired / necessary for its application. Such additives, when present, may include but are not necessarily limited to, antioxidants, ultraviolet absorbers, stabilizers (e.g., hindered phenolic such as C1-C4 di -substituted phenols in alpha position vs OH; hindered cyclic amines such as having double substitution by C1-C4 alkyls in alpha position from the amine in the cycle, for example 2,2,6,6-tetramethyl piperidine derivatives; and the like and combinations thereof), foam inhibitors, flow or leveling agents, colorants, dyes, pigments, decolorizers, dispersants (wetting agents), deodorants, slip additives, fillers (e.g., including but not limited to glass particles, quartz, graphite powder, carbon black, alumina powder, silica, carbon nanotubes, non-elastomeric fibers, and the like, and combinations thereof), elastomers (such as RTV rubber, silicone rubber, and the like, and combinations thereof), tougheners (such as EPDM copolymers, ABS copolymers, and the like, and combinations thereof),thixotropic agents, matting agents, waxes, non-nitrogen-containing curing agents, any additive conventionally utilized in coating, sealant, adhesive, ink or molding compositions, and combinations thereof. When present in the curable composition, the additive(s) may individually or collectively comprise from 0.001 wt% to 70 wt%, such as from 0.005 wt% to 50 wt%, from 0.01 wt% to 30 wt%, or from 0.001 wt% to 5.0 wt%, based on the total weight of the curable composition. In alternative embodiments, the curable compositions of the present disclosure may optionally be substantially free from one, some, or all of such additives and / or may optionally be free from one, some, or all such intentionally added additives.Ethylenically Unsaturated Compounds

[0056] In some cases, in addition to epoxy-containing compounds (a), the curable composition can comprise ethylenically unsaturated compounds (e.g., independently polymerizable such as by addition polymerization and / or reactive with one or more thiol / mercaptan / sulfhydryl functional groups on the polythiol curing agent). Non-limiting examples of ethylenically unsaturated compounds can include mono-(meth)acrylate-functionalized monomers, poly-(meth)acrylate- functionalized monomers, and combinations thereof. Details regarding such ethylenically unsaturated compounds, their amounts, their polymerization / curing conditions, and other relevant details can be found, for example in a co-pending European patent application filed on the same day as this application and entitled “Curable Composition Comprising a Polythiol”, the entire and / or relevant contents of which are hereby incorporated by reference. In some alternative embodiments, the curable composition may comprise substantially no ethylenically unsaturated compounds or substantially no mono- / poly- (meth)acrylate.Initiators

[0057] Although the curable compositions according to the present disclosure typically react under ambient or controlled (elevated or reduced) temperatures without initiation, an initiator may be included in some embodiments, particularly in situations where an ethylenically unsaturated (polymerizable / reactive) component is also present (in alternative embodiments, the curable composition may comprise substantially no additional initiators, other than components (a), (b), and (c)). Being consumptive, initiators should be understood as clearly distinct from curing enhancement catalysts (component (c)). In many embodiments, particularly in but not limited tothose where an ethylenically unsaturated component is not present or intentionally added (e.g., for polymerization purposes), the curable composition can be substantially free of initiator, or free of intentionally added initiator.

[0058] When an initiator is present, it can be a free radical initiator (including photoinitiators and / or thermal initiators) and / or a cationic initiator e.g., iodonium salts, sulfonium salts, and the like, and combinations thereof, which can be activated such as by actinic radiation to undergo (homolytic) bond cleavage, which can cause reaction with a proton donor to give a Bronsted / Lewis acid).

[0059] Non-limiting types of photoinitiators may include, for example, benzoins, benzoin ethers, acetophenones, a-hydroxy acetophenones, benzyl, benzyl ketals, anthraquinones, phosphine oxides, acylphosphine oxides, a-hydroxyketones, phenylglyoxylates, a-aminoketones, benzophenones, thioxanthones, xanthones, acridine derivatives, phenazene derivatives, quinoxaline derivatives, triazine compounds, benzoyl formates, aromatic oximes, metallocenes, acylsilyl or acylgermanyl compounds, camphorquinones, polymeric derivatives thereof, and mixtures thereof.

[0060] When present, specific examples of suitable photoinitiators can include, but are not necessarily limited to, 2-methylanthraquinone, 2-ethylanthraquinone, 2-chloroanthraquinone, 2- benzyanthraquinone, 2-t-butylanthraquinone, l,2-benzo-9,10-anthraquinone, benzyl, benzoins, benzoin ethers, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, alphamethylbenzoin, alpha-phenylbenzoin, Michler’s ketone, acetophenones such as 2,2- dialkoxybenzophenones and 1 -hydroxyphenyl ketones, benzophenone, 4,4’-bis-(diethylamino) benzophenone, acetophenone, 2,2-diethyloxyacetophenone, diethyloxyacetophenone, 2- isopropylthi oxanthone, thioxanthone, diethyl thioxanthone, 1,5-acetonaphthylene, benzil ketone, a-hydroxy keto, 2,4,6-trimethylbenzoyldiphenyl phosphine oxide, benzyl dimethyl ketal, 2,2- dimethoxy-l,2-diphenylethanone, 1 -hydroxy cylclohexyl phenyl ketone, 2-methyl-l-[4- (methylthio) phenyl]-2-morpholinopropanone-l, 2-hydroxy-2-methyl-l-phenyl-propanone, oligomeric a-hydroxy ketone, benzoyl phosphine oxides, phenylbis(2,4,6- trimethylbenzoyl)phosphine oxide, ethyl(2,4,6-trimethylbenzoyl)phenyl phosphinate, anisoin, anthraquinone, anthraquinone-2-sulfonic acid, sodium salt monohydrate, (benzene) tricarbonylchromium, benzil, benzoin isobutyl ether, benzophenone / 1 -hydroxy cyclohexyl phenyl ketone, 50 / 50 blend, 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 4-benzoylbiphenyl, 2-benzyl -2-(dimethylamino)-4'-morpholinobutyrophenone, 4,4'-bis(diethylamino)benzophenone, 4,4'-bis(dimethylamino)benzophenone, camphorquinone, 2-chlorothioxanthen-9-one, dibenzosuberenone, 4,4'-dihydroxybenzophenone, 2,2-dimethoxy-2-phenylacetophenone, 4- (dimethylamino)benzophenone, 4,4'-dimethylbenzil, 2,5-dimethylbenzophenone, 3,4- dimethylbenzophenone, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide / 2-hydroxy-2- methylpropiophenone, 50 / 50 blend, 4' -ethoxy acetophenone, 2,4,6- trimethylbenzoyldiphenylphophine oxide, phenyl bis(2,4,6-trimethyl benzoyl)phosphine oxide, ferrocene, 3'-hydroxyacetophenone, 4'-hydroxyacetophenone, 3 -hydroxybenzophenone, 4- hydroxybenzophenone, 1 -hydroxy cyclohexyl phenyl ketone, 2-hydroxy-2-methylpropiophenone, 2-methylbenzophenone, 3 -methylbenzophenone, methybenzoylformate, 2-methyl-4'-(methylthio)-2-morpholinopropiophenone, phenanthrenequinone, 4'-phenoxyacetophenone, (cumene)cyclopentadienyl iron(ii) hexafluorophosphate, 9, 10-di ethoxy and 9,10- dibutoxyanthracene, 2-ethyl-9,10-dimethoxyanthracene, thioxanthen-9-one, and the like, and combinations thereof.

[0061] In particular, when present, the photoinitiator may comprise a photoinitiator selected from a benzophenone such as SpeedCure® BP (benzophenone), SpeedCure® 7005 (polymeric benzophenone), SpeedCure® 7006 (polymeric benzophenone), SpeedCure® EMK (4,4’- bis(diethylamino)benzophenone) or SpeedCure® BMS (4-benzoyl-4’ -methyl diphenyl sulphide); a thioxanthone such as SpeedCure® 7010 (polymeric thioxanthone), SpeedCure® ITX (isopropyl thioxanthone), SpeedCure® DETX (2, 4-di ethylthioxanthone) or SpeedCure® CPTX (l-chloro-4- propoxythioxanthone); an a-hydroxy acetophenone; an acylphosphine oxide such as SpeedCure® BPO (phenyl bis(2,4,6-trimethylbenzoyl)-phosphine oxide), SpeedCure® TPO (2,4,6- trimethylbenzoyldiphenylphosphine oxide) or SpeedCure® TPO-L (ethyl (2,4,6- trimethylbenzoyl)phenyl phosphinate); a phenylglyoxylate such as SpeedCure® MBF (methylbenzoylformate); and mixtures thereof.

[0062] Non-limiting types of thermal initiators may include, for example, peroxides (z.e., a compound comprising an oxygen-oxygen single bond), especially inorganic persulfate compounds such as ammonium persulfate, potassium persulfate and sodium persulfate; hydrogen peroxide; organic peroxides such as cumene hydroperoxide, t-butyl hydroperoxide, acetyl peroxide, benzoyl peroxide, lauroyl peroxide; peracids such as peracetic acid and perbenzoic acid; redox initiators wherein a reducing agent such as a ferrous compound promotes the decomposition of a peroxide;as well as other free radical producing materials such as an azo-initiator (z.e., a compound comprising an nitrogen-nitrogen double bond), for example 2,2'-azobisisobutyronitrile, 4,4'- azobis(4-cyanovaleric acid) or 2,2’-azobis(2-methylbutyronitrile); and combinations thereof.

[0063] When utilizing a photoinitiator, with or without a catalyst, it is generally advisable to employ a wavelength that corresponds to, or comprises, an effective absorption wavelength of the initiator. In various embodiments, a high pressure mercury lamp, a medium pressure mercury lamp, a low pressure mercury lamp, an excimer lamp or an LED light source may be useful for this purpose.End-use Applications

[0064] The curable compositions of the invention may be useful as adhesives, inks, coloring systems, paints, 3D printing resins (including stereolithography), thermoset resins / composites, sealants, coatings or dental resins, among other potential applications.

[0065] The present invention is therefore directed to the use of the curable composition described herein (or to a method of using the curable composition described herein) as an adhesive, an ink, a coloring system, a paint, a 3D printing resin, a thermosetting resin (and / or composite), a sealant, a coating, a photosensible material (e.g., photosensitive dry film), resins used in the manufacturing process of microelectronics and optical equipment (e.g., semiconductors and printing circuit board) or a dental resin.

[0066] Cured compositions may be especially useful for, among others, outdoor (coating) materials, in housings for electronic products, microelectronics, optical materials, home electric appliances and precision apparatuses such as cameras and watches or for adhesive and sealant materials especially in automotive, aerospace / aircraft.Additional Embodiments

[0067] Additionally or alternatively, the present disclosure can include one or more of the following embodiments.

[0068] Embodiment 1. A curable composition comprising: (a) an epoxy-containing compound; (b) a polythiol curing agent comprising at least three sulfhydryl moieties, wherein the polythiol comprises a cyclic (hetero)carbonaceous ring structure containing 0 to 4 nitrogen atoms and from 3 to 15 carbon atoms, optionally substituted by from one to four pendant groups containing from1 to 4 carbon atoms and optionally containing at least one of the sulfhydryl moieties; and (c) a curing enhancement catalyst, e.g., wherein the curable composition comprises a molar ratio of epoxy moieties to sulfhydryl moieties from about 0.95:1 to about 2.0: 1.

[0069] Embodiment 2 The composition of embodiment 1, wherein at least three of the sulfhydryl moieties in the polythiol curing agent are secondary thiol groups, wherein the polythiol curing agent comprises no nitrogen or oxygen atoms, or both.

[0070] Embodiment 3. The composition of embodiment 1 or embodiment 2, wherein the composition, when cured, exhibits one or more, two or more, three or more, four or more, or all five of the following: (i) a glass transition temperature (Tg) of at least 115°C; (ii) a lap shear strength of at least 600 psi; (iii) a shore D hardness of at least 77.0; (iv) in a solvent resistance test, a weight change when exposed to water, 10 wt% aqueous HC1, and / or 10wt% aqueous NaOH of 0.25% or less; and (v) in a solvent resistance test, at least two, at least three, at least four, or all five of the following (which collectively count as one with respect to the alphanumeric (v)): a dimensional change of 0.20% or less when exposed to distilled water; a dimensional change of 0.40% or less when exposed to 10 wt% aqueous HC1; a dimensional change of 0.50% or less when exposed to 10 wt% aqueous NaOH; a dimensional change of 1.0% or less when exposed to methyl ethyl ketone; and a dimensional change of 0.25% or less when exposed to toluene.

[0071] Embodiment 4. The composition of any one of the preceding embodiments, wherein the polythiol curing agent comprises a trimercapto-C7-C16-cycloalkane, a tetramercapto-C7-C16- cycloalkane, a l,3,5-tris(mercapto-Cl-C4-alkyl)-l,3,5-triazine-2,4,6-trione, a pentaerythritol tetrakis(mercapto-Cl-C6-alkanoate ester), a tri-Cl-C4-alkylol-C2-C6-alkane tris(mercapto-C2- C6 alkanoate ester), or a combination thereof.

[0072] Embodiment 5. The composition of any one of the preceding embodiments, wherein the polythiol curing agent comprises trimercaptocyclododecane.

[0073] Embodiment 6. The composition of any one of the preceding embodiments, wherein the polythiol curing agent is present in an amount from 3.0% to 40%, based on a total weight of the composition.

[0074] Embodiment 7. The composition of any one of the preceding embodiments, wherein the curing enhancement catalyst comprises an oxygen-containing amine.

[0075] Embodiment 8. The composition of embodiment 7, wherein the oxygen-containing amine comprises nitroguanidine, an N,N-di-Cl-C4-alkyl-C2-C6-alkanolamine, a bis(di-Cl-C4-alkylamino-C2-C6-alkyl)ether, a di-Cl-C4-alkylamino-C2-C6-alkoxy-C2-C6-alkanol, a (di-Cl- C4-alkylamino-C2-C6-alkoxy)-C2-C6-alkylamino-C2-C6-alkanol, (bis(di-C 1 -C4-alkylamino)- C2-C6-alkyl)amino-C2-C6-alkanol, morpholine, an N-Cl-C6-alkylmorpholine, a dimorpholino- di-Cl-C6-alkylether, anN-Cl-C6-alkylmorpholine, imidazole, anN-Cl-C6-alkylimidazole, a 1,2- di-Cl-C4-alkylimidazole, a dimercapto-dioxa-C7-C12-alkane, a tris(di-Cl-C4-alkylamino-C2- C6-alkyl)-hydroxy-C6-C14-aromatene, a C2-C6-alkyl,bis(di-Cl-C4-alkylamino-C2-C6-alkyl)- hydroxy-C6-C14-aromatene, a bis(di-Cl-C4-alkylamino-C2-C6-alkyl)-dihydroxy-C6-C14- aromatene, or a combination thereof.

[0076] Embodiment 9. The composition of any one of the preceding embodiments, wherein the curing enhancement catalyst comprises a non-oxygen-containing carbonaceous amine.

[0077] Embodiment 10. The composition of embodiment 9, wherein the non-oxygen-containing carbonaceous amine comprises a tetra-Cl-ClO-alkylguanidine, a penta-Cl-C5-alkylguanidine, a diazabicyclo-C7-C12-alkane, a diazabicyclo-C7-C12-alkene, a tri-C2-C12-alkylamine, a tri-C2- C12-alky amine, a di-Cl-C6-alkyl-cyclo-C5-C12-alkylamine, penta-Cl-C4-alkyl-di-C2-C4- alkylenetriamine, tetra-Cl-C4-alkyl-C2-C4-alkylenediamine, di-C2-C6-alkylpiperazine, or a combination thereof.

[0078] Embodiment 11. The composition of any one of the preceding embodiments, wherein the curing enhancement catalyst is present in an amount from 0.1% to 20%, based on a total weight of the composition.

[0079] Embodiment 12. The composition of any one of the preceding embodiments, wherein the epoxy-containing compound comprises a polyglycidyl ether of bisphenol A, a polyglycidyl ether of bisphenol F, a polyglycidyl ether of bisphenol AF, a polyglycidyl ether of bisphenol B, a polyglycidyl ether of bisphenol C, a polyglycidyl ether of bisphenol S, a polyglycidyl ether of bisphenol Z, a polyglycidyl ether of bisphenol TMC, a polyglycidyl ether of a biphenyl polyalcohol, a polyglycidyl ether of a binaphthol, a polyglycidyl ether of a polyhydroxy naphthalene, a polyglycidyl ether of a polyhydroxy benzene, a polyglycidyl ether of a hydroxy(Cl- C4 alkyl) phenol, a polyglycidyl ether of a poly[hydroxy(Cl-C4 alkyl)] benzene, a halogenated version thereof, a reaction product thereof with an extender to form an epoxy-adduct, or a combination thereof.

[0080] Embodiment 13. The composition of any one of the preceding embodiments, wherein the epoxy-containing compound: (a) is at least partially aromatic; (b) comprises substantially nonitrogen; (c) is at least 90% difunctional, based on the total weight of all epoxy-containing compounds; (d) satisfies two of (a), (b), and (c); or (e) satisfies all of (a), (b), and (c).

[0081] Embodiment 14. The composition of any one of the preceding embodiments, wherein the epoxy-containing compound is present in an amount from 10% to 85%, based on a total weight of the composition.

[0082] Embodiment 15. The composition of any one of the preceding embodiments, wherein the composition further comprises an organic solvent, an antioxidant, a pH adjuster, a colorant, a dye, a pigment, a decolorizer, a deodorant, a dispersant (wetting agent), a toughener, a thixotropic agent, a matting agent, a wax, a filler, a non-nitrogen-containing curing agent, or a combination thereof.

[0083] Embodiment 16. A kit comprising the curable composition of any of the preceding embodiments, wherein the kit comprises at least two vessels adapted to be in fluid communication with each other, wherein at least epoxy-containing compound (a) is present in one of the at least two vessels but isolated from curing enhancement catalyst (c) in at least another of the at least two vessels, so as to not allow contact and / or chemical reaction between components (a) and (c) until desired, and wherein at least a portion of polythiol curing agent (b) is optionally present in the same vessel as curing enhancement catalyst (c).

[0084] Embodiment 17. A method of forming a cured composition comprising: providing the kit of embodiment 16 and / or providing the curable composition of any of embodiments 1-15 disposed in at least two vessels; and allowing the components from the kit isolated in the at least two vessels and / or the components in the curable composition from any of claims 1-15 in the at least two vessels to fluidly contact each other outside said vessels, at a temperature sufficient to achieve substantial curing within 15 minutes, to thereby form the cured composition, wherein the cured composition comprises or represents at least a portion of an adhesive, an ink, a coloring system, a paint, a 3D printing resin, a thermosetting resin (and / or composite), a sealant, a coating, or a dental resin.

[0085] Embodiment 18. The method of embodiment 17, wherein the cured composition exhibits two or more, three or more, four or more, or all five of the following: (i) a glass transition temperature (Tg) of at least 115°C; (ii) a lap shear strength of at least 600 psi; (iii) a shore D hardness of at least 77.0; (iv) in a solvent resistance test, a weight change when exposed to water, 10 wt% aqueous HC1, and / or 10 wt% aqueous NaOH of 0.25% or less; and (v) in a solventresistance test, at least two, at least three, at least four, or all five of the following (which collectively count as one with respect to the alphanumeric (v): a dimensional change of 0.20% or less when exposed to water; a dimensional change of 0.40% or less when exposed to 10 wt% aqueous HC1; a dimensional change of 0.50% or less when exposed to 10 wt% aqueous NaOH; a dimensional change of 1.0% or less when exposed to methyl ethyl ketone; and a dimensional change of 0.25% or less when exposed to toluene.

[0086] The following Examples are intended to support and / or exemplify, but not necessarily limit, the scope of the invention, as recited in the claims. In this disclosure, the roots of the inclusive words “comprising” and “including” can alternatively include exclusionary or semi- exclusionary terms, such as variations of “consisting of’ and / or “consisting essentially of’, respectively, the latter of which should be understood to be given the meaning provided by United States case law.EXAMPLES

[0087] As described in these Examples, commercially available epoxy formulations, e.g., as sold under the tradenames 3M DP100 Clear™, 3M DP100 FR Cream™, 3M DP125 Translucent™, 3M DP190 Translucent™, MG Chemicals 8332™, and Lord 363™ (each available through their respective company manufacturers and / or through second-hand distributors, including Amazon, TestEquity, Grainger, and Ellsworth Adhesives) were used as comparators to the inventive formulations.

[0088] As used in these Examples, pentaerythritol tetrakis(3-mercaptopropionate) (PETMP), trimethylolpropane tris(3-mercaptopropionate) (TMPMP), tris(dimethylaminomethyl)-2,4,6- phenol (TDAMP; commercially available as DMP-30™ or Versamine EH-30™), 1,4- diazabicyclo[2.2.2]octane (DABCO or triethylenediamine; commercially available as in solution as DABCO 33LV™, which is -33% DABCO in 67% dipropylene glycol), 1,8- diazabicyclo[5.4.0]undec-7-ene (DBU), and bisphenol A diglycidyl ether (BADGE or BPADGE; commercially available as DER 332™) was purchased from Sigma. Capcure 3-800™ (aka GPM800) polythiol is commercially available from Atom Adhesives, and Karenz MT PE-1™ polythiol was provided by Showa Denko (now commercially available from Resonac). Epon 826™ and Epon 828™ were purchased from Westlake Chemical (formerly Hexion). Othersolvents, such as toluene and methyl ethyl ketone, were purchased from Sigma. All chemicals were used as received.

[0089] Cold rolled steel (CRS) plates were purchased from ACT Test Panels (product #17929). 30 x 30 mm2 silicone molds were purchased from Amazon for solvent resistance testing. Empty 2-part cartridges (vessels containing various divided formulation ratios - from 1 :1 to 10: 1 by volume), dispensers, static mixers were purchased from Perigee Direct, and physical combinations of these elements are shown in Figure 1. PTFE tapes, 1” and 0.5” (#5480, commercially available from 3M), were purchased from Uline and / or Grainger. Steel weight bars (for even pressure for adhesive curing, -150 grams each, ~”1 x -1” x -12”) and PTFE films (to cover non-target area for preventing undesired adhesion, -0.002” and -0.003”, or 2-3 mils, in thickness) were purchased from Grainger.

[0090] For use in the Examples, cartridge vessels (A and B from Figure 1) were degassed by SpeedMixer (DAC 1200-300™, commercially available from FlackTek) with optional vacuum function. Each of the compositional / formulational elements (components) was transferred to a cartridge and sealed by sealing pistons to maintain essentially a gas-tight environment. For cartridge having -10:1 by volume formulation rations, physical mixtures of epoxy and polythiol components did not appear to substantially increase viscosity for -1 week, indicating substantially no reaction of these components under ambient condition. It is believed that all comparator adhesives used herein contained TDAMP as a curing enhancement catalyst.

[0091] Examples 1-7 and Comparative Examples 8-13

[0092] Inventive and comparative epoxy -based formulations were provided with the cartridges, amounts / ratios, and other data shown in Table 1 below. Inventive Examples are identified only by a number, whereas Comparative Examples are identified by the letter “C” plus a number.Table 1.! Curing Agent not specified. However, based on information from each SDS, in each case, the curing agent is believed to exhibit a similar chemistry to Capcure 3-800™.xAmine system components are not reported in Table 1.Max / Min values of epoxy (**) and curing agent (*) loading parts were reported based on data taken from each SDS. *** Molar testing of polythiol curing agent-based commercial formulations C8-C11 were conducted to determine the molar equivalent ratio of epoxy groups to thiol groups, and, based on the assumption of commercially available BADGE epoxy and SDS information, calculated max / min values were reported.

[0093] In Table 1, the epoxy-containing compound in each Inventive Example was BADGE (commercial Epon 826™ was used), and the curing enhancement catalyst in each Inventive Example was TDAMP (commercial DMP-30™ was used). TAIC means l,3,5-tris(3- mercaptopropyl)-l,3,5-triazine-2,4,6(lH,3H,5H)-trione which, as a product, may contain other compounds not isolated out during the making of TAIC. CDT means cyclododecanetrithiol, which, as a product, may contain other carbon number trithiols ranging from C9-C15, as well as a minor amount (less than 20% by weight, less than 10% by weight, less than 5% by weight, or less than 1% by weight) of C9-C15 dithiols.

[0094] The formulations of Examples 1-7 and Comparative Examples C8-C13 were tested to determine set time (also called “working time”, represents approximation of time to kinetically cure). To an A3 size (white) cardboard, ~0.5” masking tape (commercially available 3M 234™high temperature tape) was applied as a guideline. Along the line, the formulations were dispensed from their cartridges at room temperature (~17-23°C) and carefully observed to check for “stickiness” over time. Once each formulation maintained approximately static properties, as observed using visual and / or tactile means, set time was recorded, with values representing numerical averages of (at least) three tests conducted under approximately identical conditions. Set time results are shown in Table 2 below.

[0095] The formulations of Examples 1-7 and Comparative Examples C8-C13 were also tested to determine glass transition temperature (Tg). Tg’s were measured using an RDA III™ strain- controlled rotational rheometer, alternatively called a dynamic mechanical analyzer or DMA (commercially available from Anton Paar), running TA Instruments’ Orchestrator™ software, in torsion mode. DMA testing samples were -10 mm x -130 mm monoliths made by casting formulations in a silicone mold in a closed environment and allowing to cure for -1 week at room temperature (~17-23°C). Thereafter, each sample was tested at a frequency of -6.283 rad / s from an initial temperature of ~130°C to a final temperature of ~180°C at a ramp rate of ~5°C / min, involving an applied strain of 0.03%. Each reported Tg represents the average of at least two analyses and is shown in Table 2 below.

[0096] The formulations of Examples 1-7 and Comparative Examples C8-C13 were also tested to determine Shore D hardness, which was measured using a Phase II Plus PHT-980™ durometer. Hardness samples were -45 mm x -65 mm monoliths made by casting formulations in a silicone mold in a closed environment and allowing to cure for -1 week at room temperature (~17-23°C). Analyses were done according to ASTM D2240, with reported values representing an average of at least five measurements, as shown in Table 2 below.

[0097] The formulations of Examples 1-7 and Comparative Examples C8-C13 were also tested to determine solvent resistance. Solvent resistance samples were -30 mm x -30 mm monoliths made by casting formulations in a silicone mold in a closed environment and allowing to cure for -1 week at room temperature (~17-23°C). Samples were weighed and measured (in length and / or width), then immersed (completely covered) in each of five media (solvents) in a closed environment at room temperature (~17-23°C) for -1 week. The samples were then removed from the medium / solvent, towel dried, and their dimensions and weight re-measured. Percent weight increase / decrease and percent dimensional increase / decrease (average of measurements in length and width dimensions only, not in height dimension) are calculated, said increases (positive- 1 -numbers) may reflect solvent absorption / uptake and said decreases (negative numbers) may reflect degradation and / or solubilization of unreacted / lower molecular weight components, respectively. The five media were deionized water, 10% (w / v) aqueous hydrochloric acid (10% HC1 in water), 10% (w / v) aqueous sodium hydroxide (10% NaOH in water), methyl ethyl ketone (MEK), and toluene.Table 2.

[0098] Although not shown in Table 2, other tests substituted l,4-diazabicyclo[2.2.2]octane (DABCO; commercially available in solution as DABCO-LV 33™) and 1,8- diazabicyclo[5.4.0]undec-7-ene (DBU) for the TDAMP curing enhancement catalyst used in Examples 1-7 at varying concentrations (less than 1 part per 100 parts epoxy, ~1.6 parts per 100 parts epoxy, -4.8 parts per 100 parts epoxy, and -14 parts per 100 parts epoxy). At similar concentration (-14 parts per 100 parts epoxy) to that of Examples 2-4, using the CDT polythiol curing agent, those same formulations with DABCO curing enhancement catalyst exhibited a set time of less than 2 minutes. At -4.8 parts, the set time was measured at -2-3 minutes, and at -1.6 parts, the set time was measured at -6-7 minutes, which is approximately equal to the relatively quick set times of the PETMP and commercial epoxy formulations of Example 5 and Comparative Examples C8-C11. At less than 1 part, the DABCO enhancement catalyst versions of Examples 2-4 also exhibited a set time around 15-21 minutes, similar to those with TDAMP enhancement catalyst.

[0099] The formulations of Examples 1-7 and Comparative Examples C8-C13 were also tested to determine lap shear strength. Lap shear strength measurements were made using Instron 5500R™ equipment running Bluehill v3.0 software, using parameters matched to ASTM D1002 (e.g., ramp rate of ~0.05’7min). Lap shear samples were made by applying each formulation to -1” x -4” cold-rolled steel (CRS) plates (ACT test panel #17929) in a ~0.5” layer across the upper portion of a plate on which a nonstick (PTFE / Teflon™) tape was disposed (between sample layer and CRS plate), with a -0.5” gap from the joining edge and a -1” margin on the opposite side of the layer, representing a common overlap as shown in Figure 2. An alternative configuration has the -0.5” formulation cast layer at the very top of the plate, still with nonstick tape beneath it and extending to a -1” margin below (non-overlap version). In both cases, a weight was applied to encourage relatively uniform layer thickness - measured thicknesses were relatively consistent at an average of about 0.1”. Only results from the common overlap sample measurements are reported here, and such results represent an average of at least 5 samples (e.g., about 10 samples) tested, as shown in Table 3. Before formulations were applied, the plates were cleaned once with methyl ethyl ketone (MEK), sanded using -180 grit sandpaper, and cleaned again with MEK before samples of the curable compositions were applied to each plate. Although statistical error / variability are not show for these samples, the magnitude of the error range is -20% or higher, which is significantly larger than that of the other average values reported herein.Table 3.

[0100] Even given the larger potential error range, it should be noted that the samples with lower relative epoxy / thiol molar ratios exhibited significant improvement in lap shear strength (as compared to higher molar ratios), approximating or surpassing commercial comparators.

Claims

CLAIMSWhat is claimed is:

1. A curable composition comprising:(a) an epoxy-containing compound;(b) a polythiol curing agent comprising at least three sulfhydryl moieties, wherein the polythiol comprises a cyclic (hetero)carbonaceous ring structure containing 0 to 4 nitrogen atoms and from 3 to 15 carbon atoms, optionally substituted by from one to four pendant groups containing from 1 to 4 carbon atoms and optionally containing at least one of the sulfhydryl moieties; and(c) a curing enhancement catalyst, wherein the curable composition comprises a molar ratio of epoxy moieties to sulfhydryl moieties from about 0.95:1 to about 2.0: 1.

2. The composition of claim 1, wherein at least three of the sulfhydryl moieties in the polythiol curing agent are secondary thiol groups, wherein the polythiol curing agent comprises no nitrogen or oxygen atoms, or both.

3. The composition of claim 1 of claim 2, wherein the composition, when cured, exhibits one or more of the following:(i) a glass transition temperature (Tg) of at least 115°C;(ii) a lap shear strength of at least 600 psi;(iii) a shore D hardness of at least 77.0;(iv) in a solvent resistance test, a weight change when exposed to water, 10 wt% aqueous HC1, and / or 10wt% aqueous NaOH of 0.25% or less; and(v) in a solvent resistance test, at least three of the following: a dimensional change of 0.20% or less when exposed to distilled water; a dimensional change of 0.40% or less when exposed to 10 wt% aqueous HC1; a dimensional change of 0.50% or less when exposed to 10 wt% aqueous NaOH; a dimensional change of 1.0% or less when exposed to methyl ethyl ketone; and a dimensional change of 0.25% or less when exposed to toluene.

4. The composition of any one of the preceding claims, wherein the polythiol curing agent comprises a trimercapto-C7-C16-cycloalkane, a tetramercapto-C7-C16-cycloalkane, a 1,3,5-tris(mercapto-Cl-C4-alkyl)-l, 3, 5-triazine-2, 4, 6-trione, a pentaerythritol tetrakis(mercapto-Cl- C6-alkanoate ester), a tri-Cl-C4-alkylol-C2-C6-alkane tris(mercapto-C2-C6 alkanoate ester), or a combination thereof.

5. The composition of any one of the preceding claims, wherein the polythiol curing agent comprises trimercaptocyclododecane.

6. The composition of any one of the preceding claims, wherein the polythiol curing agent is present in an amount from 3.0% to 40%, based on a total weight of the composition.

7. The composition of any one of the preceding claims, wherein the curing enhancement catalyst comprises nitroguanidine, an N,N-di-Cl-C4-alkyl-C2-C6-alkanolamine, a bis(di-Cl-C4- alkylamino-C2-C6-alkyl)ether, a di-Cl-C4-alkylamino-C2-C6-alkoxy-C2-C6-alkanol, a (di-Cl- C4-alkylamino-C2-C6-alkoxy)-C2-C6-alkylamino-C2-C6-alkanol, (bis(di-C 1 -C4-alkylamino)- C2-C6-alkyl)amino-C2-C6-alkanol, morpholine, an N-Cl-C6-alkylmorpholine, a dimorpholino- di-Cl-C6-alkylether, anN-Cl-C6-alkylmorpholine, imidazole, anN-Cl-C6-alkylimidazole, a 1,2- di-Cl-C4-alkylimidazole, a dimercapto-dioxa-C7-C12-alkane, a tris(di-Cl-C4-alkylamino-C2- C6-alkyl)-hydroxy-C6-C14-aromatene, a C2-C6-alkyl,bis(di-Cl-C4-alkylamino-C2-C6-alkyl)- hydroxy-C6-C14-aromatene, a bis(di-Cl-C4-alkylamino-C2-C6-alkyl)-dihydroxy-C6-C14- aromatene, or a combination thereof.

8. The composition of any one of the preceding claims, wherein the curing enhancement catalyst comprises a tetra-Cl-ClO-alkylguanidine, a penta-Cl-C5-alkylguanidine, a diazabicyclo- C7-C12-alkane, a diazabicyclo-C7-C12-alkene, a tri-C2-C12-alkylamine, a tri-C2-C12- alkyamine, a di-Cl-C6-alkyl-cyclo-C5-C12-alkylamine, penta-Cl-C4-alkyl-di-C2-C4- alkylenetriamine, tetra-Cl-C4-alkyl-C2-C4-alkylenediamine, di-C2-C6-alkylpiperazine, or a combination thereof.

9. The composition of any one of the preceding claims, wherein the curing enhancement catalyst is present in an amount from 0.1% to 20%, based on a total weight of the composition.

10. The composition of any one of the preceding claims, wherein the epoxy-containing compound comprises a polyglycidyl ether of bisphenol A, a polyglycidyl ether of bisphenol F, a polyglycidyl ether of bisphenol AF, a polyglycidyl ether of bisphenol B, a polyglycidyl ether of bisphenol C, a polyglycidyl ether of bisphenol S, a polyglycidyl ether of bisphenol Z, a polyglycidyl ether of bisphenol TMC, a polyglycidyl ether of a biphenyl polyalcohol, a polyglycidyl ether of a binaphthol, a polyglycidyl ether of a polyhydroxy naphthalene, apolyglycidyl ether of a polyhydroxy benzene, a polyglycidyl ether of a hydroxy(Cl-C4 alkyl) phenol, a polyglycidyl ether of a poly[hydroxy(Cl-C4 alkyl)] benzene, a halogenated version thereof, a reaction product thereof with an extender to form an epoxy-adduct, or a combination thereof.

11. The composition of any one of the preceding claims, wherein the epoxy-containing compound:(a) is at least partially aromatic;(b) comprises substantially no nitrogen;(c) is at least 90% difunctional, based on the total weight of all epoxy-containing compounds;(d) satisfies two of (a), (b), and (c); or(e) satisfies all of (a), (b), and (c).

12. The composition of any one of the preceding claims, wherein the epoxy-containing compound is present in an amount from 10% to 85%, based on a total weight of the composition.

13. The composition of any one of the preceding claims, wherein the composition further comprises an organic solvent, an antioxidant, a pH adjuster, a colorant, a dye, a pigment, a decolorizer, a deodorant, a dispersant (wetting agent), a toughener, a thixotropic agent, a matting agent, a wax, a filler, a non-nitrogen-containing curing agent, or a combination thereof.

14. A kit comprising the curable composition of any of the preceding claims, wherein the kit comprises at least two vessels adapted to be in fluid communication with each other, wherein at least epoxy-containing compound (a) is present in one of the at least two vessels but isolated from curing enhancement catalyst (c) in at least another of the at least two vessels, so as to not allow contact and / or chemical reaction between components (a) and (c) until desired, and wherein at least a portion of polythiol curing agent (b) is optionally present in the same vessel as curing enhancement catalyst (c).

15. A method of forming a cured composition comprising: providing the kit of claim 14; and allowing the components isolated in the at least two vessels to fluidly contact each other outside said vessels, at a temperature sufficient to achieve substantial curing within 15 minutes, to thereby form the cured composition, wherein the cured composition comprises or represents a portion of an adhesive, an ink, a coloring system, a paint, a 3D printing resin, a thermosetting resin (and / or composite), a sealant, a coating, or a dental resin.

Images