Flame-retardant curable compositions

Abstract

A flame-retardant curable composition comprises at least 25% by weight of a monomer having at least one (meth)acrylate group, based on the total weight of the polymerizable components; at least 5% by weight of a phosphorus-containing non-reactive filler, based on the total weight of the polymerizable components; and a free radical photoinitiator, wherein the phosphorus-containing non-reactive filler is in solid form at room temperature and contains at least 10% by weight of phosphorus, and wherein the composition is substantially free of any halogens. A cured composition and a three-dimensional printed article comprising the cured composition are also described.

Description

[0001] Flame retardant compositions are commonly used in many applications, but may have drawbacks such as the need for halogens or metals or flame retardant thermosetting materials (FR thermosetting materials). These additives, when used to achieve the desired level of flame retardancy, can lead to a loss of flame retardancy over time when exposed to high temperatures, or poor resolution during 3D printing. In particular, halogen-containing flame retardant compositions are toxic and harmful to the environment.

[0002] As a method for imparting flame retardancy without these components, US 2022 / 0185928 A1 discloses the combined use of liquid phosphate fillers with isocyanurate-containing monomers. However, the use of liquid fillers leads to reduced flame retardancy and produces defective materials over time or upon exposure to heat. Liquid fillers leach from the cured material at elevated temperatures, regardless of their boiling point. Using solid FR fillers instead of liquid FR fillers is advantageous to ensure the flame retardant lifespan of these materials.

[0003] The compositions of the present invention overcome the aforementioned disadvantages by achieving flame retardancy without requiring large amounts of halogens, metals, or FR thermosetting materials. Furthermore, by using solid fillers that do not leach out over time at high temperatures, the compositions retain their flame retardancy over time and also provide good resolution during 3D printing. Summary of the Invention

[0004] One aspect of the present invention is a curable composition comprising, substantially consisting of, or consisting of the following:

[0005] - At least 25% by weight of at least one isocyanurate-containing monomer having at least one (meth)acrylate group, based on the total weight of the polymerizable components;

[0006] - At least 5% by weight of a phosphorus-containing non-reactive filler based on the total weight of the polymerizable components, wherein the filler is in solid form at room temperature and contains at least 10% by weight of phosphorus; and

[0007] - Free radical photoinitiators

[0008] The composition therein is substantially free of any halogens (e.g., halogen-containing compounds).

[0009] One aspect of the present invention is a cured composition formed from a curable composition as described herein.

[0010] One aspect of the invention is an article comprising a cured composition as described herein.

[0011] One aspect of the present invention is a three-dimensional (3D) printed article comprising a cured composition as described herein.

[0012] One aspect of the present invention is a method for increasing the flame retardancy of an article, comprising coating at least one surface of the article with a curable composition as described herein.

[0013] Various embodiments of the invention have been described in more detail throughout this disclosure. The foregoing general description and the following detailed description provide exemplary embodiments and offer a general overview or framework for understanding the nature and characteristics of the technology. Furthermore, these descriptions are merely illustrative and are not intended to limit the scope of the claims in any way. Detailed Implementation

[0014] definition

[0015] The term "photochemical source" refers to an electromagnetic radiation source capable of inducing photochemical reactions, with at least a portion of its electromagnetic radiation falling within the ultraviolet range (100 nm to 400 nm).

[0016] The term "aliphatic" refers to saturated and unsaturated hydrocarbons, straight-chain (i.e., unbranched) or branched, cyclic or acyclic, excluding aromatic groups, and including but not limited to alkyl, alkenyl, and alkynyl groups. Therefore, descriptive aliphatic groups include, but are not limited to, for example, methyl, ethyl, n-propyl, isopropyl, allyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, sec-pentyl, isopentyl, n-hexyl, sec-hexyl, alkenyl such as vinyl, propenyl, 1-methyl-2-buten-1-yl, and alkynyl such as ethynyl, 2-propynyl (propynyl), and 1-propynyl.

[0017] The terms "cationic curable monomer," "cationic curable compound," "cationic polymerizable monomer," or "cationic polymerizable compound" refer to monomers / compounds that contain curable / polymerizable functional groups that can be polymerized via a cationic mechanism. For example, caticic curable / polymerizable functional groups may contain heterocyclic groups or carbon-carbon double bonds substituted with electron-donating groups.

[0018] The terms “cationically curable resin” or “cationically polymerizable resin” refer to a mixture of organic compounds / monomers in which at least some form a polymer in the presence of a cationic initiator.

[0019] The term "curable composition" refers to a composition whose properties are altered based on a stimulus. Typically, curable compositions as described herein are cured by polymerization and / or crosslinking. Generally, those curable compositions cure upon the addition of energy to the system, which can be in the form of photochemical light, heat, or both. Typically, when the compounds in the curable composition contain carbon-carbon double bonds, polymerization (curing) involves the reaction of such carbon-carbon double bonds.

[0020] The term "epoxide" refers to a compound containing one or more epoxy groups, such as a monomer.

[0021] The term "photoinitiator" refers to any type of substance that, upon exposure to radiation (e.g., photochemical radiation), forms a substance that initiates a reaction and cures a polymerizable organic substance in a curable composition. Typically, such polymerization (curing) involves the reaction of these carbon-carbon double bonds when the compound present in the reactive component contains carbon-carbon double bonds.

[0022] The term "free radical photoinitiator" refers to a compound that undergoes a photoreaction upon absorbing light, producing reactive free radicals. These reactive substances then initiate the curing (polymerization) of the reactive components of a curable composition.

[0023] The term "free radical polymerizable resin" refers to a resin that can polymerize when exposed to free radicals.

[0024] The term "(meth)acrylate group" refers to either an acrylate group or a methacrylate group. An acrylate group corresponds to a group with the formula -OC(=O)-CH=CH2. A methacrylate group corresponds to a group with the formula -OC(=O)-C(CH3)=CH2.

[0025] The term "monofunctional" refers to a compound having a single functional group. For example, a monofunctional (meth)acrylate monomer is a monomer having a single (meth)acrylate group.

[0026] The term "monomer" refers to a molecule having one or more polymerizable functional groups. Monomers have a single molecular weight, typically below 1000 g / mol, preferably from 100 to 950 g / mol. As is generally recognized in the art, commercial products of particular monomers may contain impurities or other chemicals.

[0027] The term "number-average molecular weight" or "Mn" refers to the statistical average molecular weight of polymer chains in a sample or group. Unless otherwise explicitly stated, the number-average molecular weights reported herein were determined using size exclusion chromatography (SEC).

[0028] The term "oligomer" refers to a molecule having a molecular weight distribution and may or may not have one or more polymerizable functional groups. Oligomers can be the product of the reaction of two or more monomers and typically have a number-average molecular weight of 500 g / mol or greater, preferably from 500 g / mol to 30,000 g / mol, more preferably from 1,000 g / mol to 8,000 g / mol. Oligomers do not always have a single molecular weight.

[0029] The term "cycloalkyl" refers to a monovalent hydrocarbon group that contains an optionally substituted non-aromatic ring. A cycloalkyl group may contain a single non-aromatic ring or more than one non-aromatic ring. When a cycloalkyl group contains more than one ring, these rings may be covalently fused, bridged, or linked. Examples of cycloalkyl groups include cyclopentyl, cyclohexyl, isobenyl, dicyclopentyl, tricyclodecane, and adamantyl, any of which may be optionally substituted.

[0030] The term "heterocyclic alkyl" refers to an optionally substituted cycloalkyl group in which one or more ring atoms are independently replaced by a heteroatom selected from O, N, or S. Examples of heterocyclic alkyl groups include tetrahydrofuran, 1,3-dioxacyclopentane, tetrahydropyran, and 1,3-dioxacyclohexane.

[0031] The term "aryl" refers to an optionally substituted monovalent aromatic group. An aryl group may contain a single aromatic ring (i.e., a phenyl group) or more than one ring, wherein at least one ring is aromatic. When an aryl group contains more than one ring, the rings may be covalently fused or linked (e.g., biphenyl). Each aromatic ring may optionally contain one or two additional fused rings (i.e., cycloalkyl, heteroalkyl, or heteroaryl). Examples of aryl groups include phenyl, naphthyl, tetrahydronaphthyl, biphenyl, phenanthrene, tetraphenyl, fluorenyl, tetrahydrofluorenyl, indacenyl, hexahydroindacenyl, indene, dihydroindacenyl, anthracene, and octahydroanthrayl. The term "(C6-C)" is also used. 40 "Aryl" refers to an aryl group having 6 to 40 carbon atoms, of which 6 to 14 carbon atoms are aromatic ring carbon atoms.

[0032] The term “heteroaryl” refers to an aryl group with optional substitution, in which one or more ring atoms are independently replaced by heteroatoms selected from O, N or S.

[0033] The term "optionally substituted group" means that one or more hydrogen atoms in a group can be independently substituted by a substituent selected from alkyl, cycloalkyl, aryl, heteroaryl, alkoxy, alkylaryl, haloalkyl, hydroxyl, halogen, isocyanate, nitrile, amine, oxo(=O), carboxylic acid, -C(=O)-R', -C(=O)-OR', -C(=O)NH-R', -NH-C(=O)R', -OC(=O)-NH-R', -NH-C(=O)-O-R', -C(=O)-OC(=O)-R' and -SO2-NH-R', where each R' is independently an optionally substituted group selected from alkyl, aryl and alkylaryl.

[0034] The term "weight % (wt%)" means weight percentage. Unless otherwise stated, the weight percentage of the compounds or components in a composition is expressed relative to the weight of the composition.

[0035] Isocyanurates with (meth)acrylate groups

[0036] The curable composition comprises at least one isocyanurate-containing monomer having at least one (meth)acrylate group. In one exemplary embodiment, the isocyanurate-containing monomer has one, two, or three (meth)acrylate groups, such as, but not limited to, mono-, di-, and tri-(2-hydroxyethyl)(meth)acrylate-substituted isocyanurates and their alkoxylated derivatives (e.g., ethoxylated, propoxylated, etc.). Tri-(2-hydroxyethyl)isocyanurate trimethacrylate (e.g., Sartomer's SR290) and tri-(2-hydroxyethyl)isocyanurate triacrylate (e.g., Sartomer's SR368) are shown below as exemplary embodiments, Structure 1 and Structure 2, respectively.

[0037]

[0038] In one exemplary embodiment, the isocyanurate-containing monomer has a (meth)acrylate group (i.e., a monosubstituted isocyanurate).

[0039] In one exemplary embodiment, the isocyanurate-containing monomer has two (meth)acrylate groups (i.e., a disubstituted isocyanurate).

[0040] In one exemplary embodiment, the isocyanurate-containing monomer has three (meth)acrylate groups (i.e., a trisubstituted isocyanurate).

[0041] In one exemplary embodiment, the curable composition comprises at least 25% by weight of at least one isocyanurate-containing monomer having at least one (meth)acrylate group based on the total weight of the polymerizable components, for example at least 30% by weight, for example at least 35% by weight, for example at least 45% by weight, for example at least 55% by weight, for example at least 65% by weight, for example at least 75% by weight, for example at least 85% by weight, for example at least 90% by weight, for example from 25% to 90% by weight, for example from 25% to 80% by weight, for example from 25% to 75% by weight, for example from 25% to 70% by weight, for example from 30% to 90% by weight, for example from 30% to 80% by weight, for example from 30% to 70% by weight.

[0042] In a preferred embodiment, the curable composition comprises 30% to 90% by weight of at least one isocyanurate-containing monomer having at least one (meth)acrylate group.

[0043] Other isocyanurate-containing monomers

[0044] The curable composition may also contain at least one non-acrylic isocyanurate monomer.

[0045] In one exemplary embodiment, at least one non-acrylic isocyanurate monomer is an isocyanurate having at least one thiol group or at least one allyl group.

[0046] In one exemplary embodiment, the non-acrylic isocyanurate monomer is an isocyanurate having a thiol group (i.e., a monosubstituted isocyanurate).

[0047] In one exemplary embodiment, the non-acrylic isocyanurate monomer is an isocyanurate having two thiol groups (i.e., a disubstituted isocyanurate).

[0048] In one exemplary embodiment, the non-acrylic isocyanurate monomer is an isocyanurate having three thiol groups (i.e., a trisubstituted isocyanurate).

[0049] In one exemplary embodiment, the non-acrylic isocyanurate monomer is an isocyanurate having an allyl group (i.e., a monosubstituted isocyanurate).

[0050] In one exemplary embodiment, the non-acrylic isocyanurate monomer is an isocyanurate having two allyl groups (i.e., a disubstituted isocyanurate).

[0051] In one exemplary embodiment, the non-acrylic isocyanurate monomer is an isocyanurate having three allyl groups (i.e., a trisubstituted isocyanurate).

[0052] In one exemplary embodiment, a non-acrylic isocyanurate having at least one thiol group and a non-acrylic isocyanurate having at least one allyl group are present in the curable composition.

[0053] Tri-[2-(3-mercaptopropionyloxy)ethyl]isocyanurate (e.g., Bruno Bock's TEMPIC) and triallyl isocyanurate (e.g., Sartamomer's SR533) are shown below as exemplary embodiments of non-acrylic isocyanurate-containing monomers of structures 3 and 4, respectively.

[0054]

[0055] In one exemplary embodiment, the curable composition comprises 1% to 75% by weight of a non-acrylic isocyanurate-containing monomer based on the total weight of the polymerizable components, for example, 1% to 65% by weight, for example, 1% to 55% by weight, for example, 1% to 45% by weight, for example, 3% to 75% by weight, for example, 3% to 65% by weight, for example, 3% to 55% by weight, for example, 3% to 45% by weight, for example, 5% to 75% by weight, for example, 5% to 65% by weight, for example, 5% to 5% by weight. 5% by weight, for example, 5% to 45% by weight, for example, 5% to 40% by weight, for example, 5% to 30% by weight, for example, 10% to 75% by weight, for example, 10% to 65% by weight, for example, 10% to 55% by weight, for example, 10% to 45% by weight, for example, 10% to 40% by weight, for example, 15% to 75% by weight, for example, 15% to 65% by weight, for example, 15% to 55% by weight, for example, 15% to 45% by weight, for example, 15% to 40% by weight.

[0056] Phosphorus-containing fillers

[0057] The curable composition comprises at least one non-reactive (i.e., does not participate in polymerization under curing conditions) phosphorus-containing filler, wherein the filler is in solid form at room temperature (25°C) and contains at least 10% by weight of phosphorus.

[0058] In one exemplary embodiment, the phosphorus-containing filler is in granular form.

[0059] In one exemplary embodiment, the phosphorus-containing filler is substantially insoluble in water.

[0060] In one exemplary embodiment, the phosphorus-containing filler is a phosphinate filler.

[0061] In one exemplary embodiment, the phosphorus-containing filler is a phosphonate filler.

[0062] In one exemplary embodiment, the phosphorus-containing filler is a phosphate (ester) filler, such as an inorganic phosphate (ester) filler.

[0063] In one exemplary embodiment, the phosphorus-containing filler includes, but is not limited to, polyphosphates, particularly ammonium polyphosphate (e.g., AP423), dialkylphosphinates, particularly aluminum diethylphosphinate (e.g., Clariant's OP945), red phosphorus, melamine phosphate, phosphates, solid trialkyl phosphates, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), cyclic phenoxyphosphazenes, solid phosphoramides, melamine polyphosphates, cyclic phosphonates (e.g., Antiblaze19 from Rhodia), phosphorus nitrogen oxide radicals, phosphine oxides, and mixtures thereof.

[0064] In one exemplary embodiment, the phosphorus-containing filler includes, but is not limited to, ammonium polyphosphate (e.g., AP423), aluminum diethylphosphonate (e.g., Clariant's OP945), red phosphorus, melamine phosphate, phosphate, or trialkyl phosphate.

[0065] In a preferred embodiment, the phosphorus-containing filler includes, but is not limited to, ammonium polyphosphate (e.g., AP423), aluminum diethylphosphonate (e.g., Clariant's OP945), and mixtures thereof.

[0066] In one exemplary embodiment, the cured composition has a UL-94 rating of V-2 or better, such as V-1 or better, such as V-0.

[0067] In one exemplary embodiment, the curable composition comprises at least 5% by weight of at least one non-reactive phosphorus-containing filler based on the total weight of the polymerizable components, which contains at least 10% by weight of phosphorus, for example, at least 6% by weight, for example, at least 8% by weight, for example, at least 10% by weight, for example, at least 12% by weight, for example, at least 15% by weight, for example, at least 20% by weight, for example, at least 25% by weight, for example, at least 35% by weight, for example, at least 45% by weight, for example, at least 55% by weight, for example, at least 65% by weight, for example, at least 75% by weight, for example, 5% to 75% by weight, for example, 5% to 75% by weight. 65% by weight, for example, 5% to 55% by weight, for example, 5% to 45% by weight, for example, 5% to 35% by weight, for example, 5% to 25% by weight, for example, 5% to 20% by weight, for example, 5% to 15% by weight, for example, 8% to 75% by weight, for example, 8% to 65% by weight, for example, 8% to 55% by weight, for example, 8% to 45% by weight, for example, 8% to 35% by weight, for example, 8% to 25% by weight, for example, 12% to 20% by weight, for example, 10% to 75% by weight, for example, 10% to 65% by weight. For example, 10% to 55% by weight, for example, 10% to 45% by weight, for example, 10% to 35% by weight, for example, 10% to 25% by weight, for example, 10% to 20% by weight, for example, 12% to 75% by weight, for example, 12% to 65% by weight, for example, 12% to 55% by weight, for example, 12% to 45% by weight, for example, 12% to 35% by weight, for example, 12% to 25% by weight, for example, 12% to 20% by weight, for example, 15% to 75% by weight, for example, 15% to 65% by weight, for example, 15% by weight % to 55% by weight, for example, 15% to 45% by weight, for example, 15% to 35% by weight, for example, 15% to 25% by weight, for example, 20% to 75% by weight, for example, 20% to 65% by weight, for example, 20% to 55% by weight, for example, 20% to 45% by weight, for example, 20% to 35% by weight, for example, 30% to 75% by weight, for example, 30% to 65% by weight, for example, 30% to 55% by weight, for example, 40% to 75% by weight, for example, 40% to 65% by weight, for example, 50% to 75% by weight.

[0068] In a preferred embodiment, the curable composition comprises at least one non-reactive phosphorus-containing filler at a weight percentage of 8% to 75% based on the total weight of the polymerizable components.

[0069] In another preferred embodiment, the curable composition comprises 15% to 75% by weight of at least one non-reactive phosphorus-containing filler based on the total weight of the polymerizable components.

[0070] In one exemplary embodiment, the phosphorus-containing filler contains at least 10% by weight of phosphorus, such as at least 15% by weight of phosphorus, such as at least 20% by weight of phosphorus, such as at least 25% by weight of phosphorus, such as at least 35% by weight of phosphorus, such as at least 45% by weight of phosphorus, such as at least 55% by weight of phosphorus, such as at least 65% by weight of phosphorus, such as at least 75% by weight of phosphorus, such as at least 85% by weight of phosphorus, such as at least 95% by weight of phosphorus, such as 10% to 100% by weight of phosphorus, such as 10% by weight of phosphorus. Phosphorus from 1% to 90% by weight, for example, 10% to 80% by weight, for example, 10% to 70% by weight, for example, 10% to 60% by weight, for example, 10% to 50% by weight, for example, 10% to 40% by weight, for example, 10% to 30% by weight, for example, 10% to 20% by weight, for example, 20% to 100% by weight, for example, 20% to 90% by weight, for example, 20% to 80% by weight. For example, 20% to 70% by weight of phosphorus, for example, 20% to 60% by weight of phosphorus, for example, 20% to 50% by weight of phosphorus, for example, 20% to 40% by weight of phosphorus, for example, 30% to 100% by weight of phosphorus, for example, 30% to 90% by weight of phosphorus, for example, 30% to 80% by weight of phosphorus, for example, 30% to 70% by weight of phosphorus, for example, 30% to 60% by weight of phosphorus, for example, 30% to 50% by weight of phosphorus, for example, 40% to 100% by weight of phosphorus, for example, 40% to 80% by weight of phosphorus, for example, 50% to 100% by weight of phosphorus.

[0071] It has been observed that there is an inverse relationship between the amount of at least one isocyanurate-containing monomer having at least one (meth)acrylate group in the curable composition and the amount of at least one non-reactive phosphorus-containing filler. Therefore, as the amount of isocyanurate-containing monomer having at least one (meth)acrylate group increases, the amount of phosphorus-containing filler can decrease without a decrease in the flame retardant properties of the composition. Alternatively, as the amount of phosphorus-containing filler increases, the amount of isocyanurate-containing monomer having at least one (meth)acrylate group can decrease without a decrease in the flame retardant properties of the composition. Increasing the amount of both the isocyanurate-containing monomer having at least one (meth)acrylate group and the phosphorus-containing filler allows for improved flame retardancy in increasingly thinner objects (e.g., objects 5 inches long and 0.5 inches wide with varying thicknesses).

[0072] Free radical photoinitiators

[0073] The curable composition comprises at least one free radical photoinitiator. The free radical photoinitiator is operable to cure the free radical polymerizable resin. Typically, free radical photoinitiators can employ two different modes of action and are classified as Norrish Type I and Norrish Type II photoinitiators based on their mode of action. In some embodiments, the free radical photoinitiator comprises a Norrish Type I photoinitiator, a Norrish Type II photoinitiator, or both.

[0074] As used herein, the term "activity" in relation to Norrish type I and Norrish type II activity is intended to refer to Norrish photoinitiation and similar reactions. For example, a photoinitiator with Norrish type I activity would be one that, upon exposure to photochemical radiation within a selected wavelength range, undergoes a cleavage reaction to form a radical fragment of the original photoinitiator. For an initiator with Norrish type II activity, exposure to photochemical radiation within a selected wavelength range induces the formation of a radical substance that can abstract hydrogen to generate a second radical substance capable of initiating photopolymerization. The Norrish type I and Norrish type II mechanisms are known to those skilled in the art.

[0075] Suitable classes of free radical photoinitiators for curable compositions as described herein include, but are not limited to, benzoin, benzoin ether, acetophenone, α-hydroxyacetophenone, benzyl ketal, anthraquinone, phosphine oxide, acylphosphine oxide, α-hydroxy ketone, phenylglyoxylate, α-amino ketone, benzophenone, thioxanthone, xanthones, acridine derivatives, phenazene derivatives, quinoxaline derivatives, triazine, benzoylcarbamate, aromatic oximes, metallocene, acylsilyl or acylgermanyl compounds, camphorquinone, their polymeric derivatives, and mixtures thereof.

[0076] Examples of suitable free radical photoinitiators include, but are not limited to, 2-methylanthraquinone, 2-ethylanthraquinone, 2-chloroanthraquinone, 2-benzylanthraquinone, 2-tert-butylanthraquinone, 1,2-benzo-9,10-anthraquinone, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, α-methylbenzoin, α-phenylbenzoin, Michler ketone, 2,2-dialkoxybenzophenone, 1-hydroxyphenyl ketone, benzophenone, 4,4'-bis-(diethylamino)benzophenone, acetophenone, 2,2-diethyloxyacetophenone, diethyloxyacetophenone, 2-isopropylthioxanthone, thioxanthone, diethylthioxanthone, 1,5-acetylnaphthalene, benzoinone, α-hydroxy ketone, 2,4,6-trimethyl Benzoyl diphenylphosphine oxide, benzyl dimethyl ketal, 2,2-dimethoxy-1,2-diphenyl ethyl ketone, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinoacetone-1, 2-hydroxy-2-methyl-1-phenyl-propanone, oligo-α-hydroxy ketone, benzoyl phosphine oxide, phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide, ethyl (2,4,6-trimethylbenzoyl)phenylphosphine ester, anisolein, anthraquinone, anthraquinone-2-sulfonic acid, (benzene)tricarbonylchromium, benzoyl, benzoin isobutyl ether, benzophenone / 1-hydroxycyclohexylphenyl ketone (50 / 50 blend), 3,3′,4,4′-benzophenone tetra Carboxylic acid dianhydride, 4-benzoylbiphenyl, 2-benzyl-2-(dimethylamino)-4′-morpholinophenylbutanone, 4,4′-bis(diethylamino)benzophenone, 4,4′-bis(dimethylamino)benzophenone, camphorquinone, 2-chlorothiazol-9-one, dibenzocycloheptenone, 4,4′-dihydroxybenzophenone, 2,2-dimethoxy-2-phenylacetophenone, 4-(dimethylamino)benzophenone, 4,4′-dimethylbenzoin, 2,5-dimethylbenzophenone, 3,4-dimethylbenzophenone, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide / 2-hydroxy-2-methylphenylacetone (50 / 50 blend), 4′-ethoxyacetophenone, 2,4 6-Trimethylbenzoyl diphenylphosphine oxide, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, ferrocene, 3′-hydroxyacetophenone, 4′-hydroxyacetophenone, 3-hydroxybenzophenone, 4-hydroxybenzophenone, 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methylphenylacetone, 2-methylbenzophenone, 3-methylbenzophenone, methylbenzoylcarbamate, 2-methyl-4'-(methylthio)-2-morpholinophenylacetone, phenanthrenequinone, 4'-phenoxyacetophenone, (cumene)cyclopentadienyl iron(ii) hexafluorophosphate, 9,10-diethoxy and 9,10-dibutoxyanthracene, 2-ethyl-9,10-dimethoxyanthracene, thioxanthone-9-one and combinations thereof.

[0077] Preferred free radical photoinitiators include benzophenone (e.g., available from Sartamomer under the trademark Speedcure). TM BP, Speedcure TM 7005 and Speedcure TM Those obtained from 7006), thioxanthone (e.g., available from Sartomer under the trademark Speedcure) TM 7010 and Speedcure TM ITX), α-hydroxyacetophenone, acylphosphine oxide (e.g., available from Sartomer under the trademark Speedcure) TM BPO, Speedcure TM TPO and Speedcure TM TPO-L (obtained) and its combinations.

[0078] In one exemplary embodiment, the free radical photoinitiator is an acylphosphine oxide. As used herein, the term "phosphine oxide" refers to a compound containing a -P (=O)- group. Acylphosphine oxide may have a structure 5

[0079]

[0080] In one exemplary embodiment, the free radical photoinitiator is phenylacetone, such as phenylacetone having structure 6.

[0081]

[0082] In one exemplary embodiment, the free radical photoinitiator is a blend of acylphosphine oxide and phenylacetone.

[0083] wetting agent

[0084] In one exemplary embodiment, the curable composition further comprises at least one wetting agent (dispersant). Suitable wetting agents include cationic, anionic, and nonionic wetting agents, as well as amphoteric and zwitterionic wetting agents.

[0085] In one exemplary embodiment, suitable wetting agents include, but are not limited to, anionic phosphate wetting agents, anionic sulfate wetting agents, anionic sulfonic acid wetting agents, anionic carboxylic acid wetting agents, nonionic alkoxylated wetting agents, amino acid-based wetting agents, cationic amine wetting agents, and cationic quaternary ammonium wetting agents. In another exemplary embodiment, suitable wetting agents include, but are not limited to, sodium lauryl sulfate, quaternary ammonium compounds (e.g., hexadecyltrimethylammonium chloride), aromatic compounds having hydrophilic polyethylene oxide chains and lipophilic or hydrophobic hydrocarbon groups (e.g., Triton X-100), nonylphenol polyethylene glycol ether, sodium salts of naphthalenesulfonic acid-formaldehyde condensation products, and combinations thereof.

[0086] In one exemplary embodiment, the curable composition comprises at least 0.1 wt% of a wetting agent based on the total weight of the polymerizable components, such as at least 0.5 wt%, at least 1 wt%, at least 3 wt%, at least 5 wt%, at least 10 wt%, from 0.1 wt% to 10 wt%, from 0.1 wt% to 5 wt%, from 0.1 wt% to 3 wt%, from 0.1 wt% to 1 wt%, from 0.5 wt% to 10 wt%, from 0.5 wt% to 5 wt%, from 0.5 wt% to 3 wt%, from 1 wt% to 10 wt%, from 1 wt% to 5 wt%, from 3 wt% to 10 wt%, from 5 wt% to 10 wt%.

[0087] Other reagents

[0088] In one exemplary embodiment, the curable composition further comprises at least one additional agent selected from olefinically unsaturated isocyanurate-free monomers, epoxide-containing monomers, oxobutane-containing monomers, oligomers thereof, and mixtures thereof.

[0089] In one exemplary embodiment, the curable composition comprises, based on 1 wt% to 75 wt% of the total weight of the polymerizable components, one or more olefinically unsaturated isocyanurate-free monomers and / or epoxide-containing monomers and / or oxetane-containing monomers, and / or their oligomers, for example, 1 wt% to 65 wt%, for example, 1 wt% to 55 wt%, for example, 1 wt% to 45 wt%, for example, 1 wt% to 35 wt%, for example, 1 wt% to 25 wt%, for example, 1 wt% to 15 wt%, for example, 5 wt% to 75 wt%, for example, 5 wt% to 65 wt%, for example, 5 wt% to 55 wt%, for example, 5 wt% to 45 wt%, for example, 5 wt% to 35 wt%, for example, 5 wt% to 5 wt%. % to 25% by weight, for example, 5% to 15% by weight, for example, 10% to 75% by weight, for example, 10% to 65% by weight, for example, 10% to 55% by weight, for example, 10% to 45% by weight, for example, 10% to 35% by weight, for example, 10% to 25% by weight, for example, 15% to 75% by weight, for example, 15% to 65% by weight, for example, 15% to 55% by weight, for example, 15% to 45% by weight, for example, 15% to 35% by weight, for example, 20% to 75% by weight, for example, 20% to 65% by weight, for example, 20% to 55% by weight, for example, 30% to 75% by weight, for example, 30% to 65% by weight.

[0090] The curable composition of the present invention may contain at least one olefinic unsaturated monomer and / or oligomer that does not contain isocyanurate groups.

[0091] In one exemplary embodiment, one or more olefinically unsaturated isocyanurate-free monomers and / or oligomers include, but are not limited to, at least one (meth)acrylate monomer, at least one (meth)acrylate oligomer, or both, wherein the (meth)acrylate monomer may be monofunctional (e.g., comprising a single (meth)acrylate group) or polyfunctional (e.g., comprising more than one (meth)acrylate group), including difunctional, trifunctional, and higher functionalities or combinations thereof, and at least one (meth)acrylate oligomer may be polyfunctional, including difunctional, trifunctional, and higher functionalities. As is well known, (meth)acrylate oligomers may have a non-integer average functionality (e.g., an average functionality between 1.9 and 2.1), and such (meth)acrylate oligomers are applicable herein.

[0092] The categories of (meth)acrylate oligomers are diverse and well known to those skilled in the art, and include urethane (meth)acrylates, (meth)acrylated epoxy resins (“epoxy (meth)acrylates”), (meth)acrylated polyesters and (meth)acrylated siloxanes.

[0093] In addition to (meth)acrylate groups, at least one (meth)acrylate oligomer may also contain urethane bonds. The at least one (meth)acrylate oligomer may be an aliphatic urethane (meth)acrylate oligomer. A suitable (meth)acrylate oligomer, under the name CN9018, is available from Sartamomer.

[0094] The class of (meth)acrylate monomers is diverse and well known to those skilled in the art. A wide range of (meth)acrylate monomers can be used herein.

[0095] Examples of suitable monofunctional (meth)acrylate monomers include, but are not limited to, (meth)acrylates of aliphatic alcohols (wherein the aliphatic alcohol may be linear, branched, or alicyclic, and may be a monohydric or polyhydric alcohol (e.g., a diol), provided that only one hydroxyl group is (meth)acrylated); (meth)acrylates of aromatic alcohols (e.g., phenols, including alkylated phenols); (meth)acrylates of alkylaryl alcohols (e.g., benzyl alcohol); oligomeric glycols and polymeric glycols (e.g., diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, polyethylene glycol, and polypropylene glycol). (Meth)acrylates; (meth)acrylates of monoalkyl ethers of glycols and oligomeric glycols; (meth)acrylates of alkoxylated (e.g., ethoxylated and / or propoxylated) aliphatic alcohols (wherein the aliphatic alcohol may be linear, branched or alicyclic, and may be a monohydric or polyhydric alcohol (e.g., a glycol), provided that only one hydroxyl group of the alkoxylated aliphatic alcohol is (meth)acrylated); (meth)acrylates of alkoxylated (e.g., ethoxylated and / or propoxylated) aromatic alcohols (e.g., alkoxylated phenols); caprolactone mono(meth)acrylates; etc.

[0096] The following compounds are specific examples of suitable monofunctional (meth)acrylate monomers: methyl methacrylate; ethyl methacrylate; n-propyl methacrylate; n-butyl methacrylate; isobutyl methacrylate; n-hexyl methacrylate; 2-ethylhexyl methacrylate; n-octyl methacrylate; isooctyl methacrylate; n-decyl methacrylate; n-dodecyl methacrylate; tridecyl methacrylate; tetradecyl methacrylate; hexadecyl methacrylate; 2-hydroxyethyl methacrylate; 2- and 3-hydroxypropyl methacrylate; 2-methoxyethyl methacrylate; 2-ethoxyethyl methacrylate; 2- and 3-ethoxypropyl methacrylate; tetrahydrofurfuryl methacrylate; alkoxylated tetrahydrofurfuryl methacrylate; 2-(2-ethoxyethoxy)ethyl methacrylate Esters; cyclohexyl (meth)acrylate; glycidyl (meth)acrylate; isodecanyl (meth)acrylate; lauryl (meth)acrylate; 2-phenoxyethyl (meth)acrylate; alkoxylated phenol (meth)acrylate; alkoxylated nonylphenol (meth)acrylate; cyclic trimethylolpropane acetal (meth)acrylate; isobornyl (meth)acrylate; tricyclodecane methanol (meth)acrylate; tert-butylcyclohexanol (meth)acrylate; trimethylcyclohexanol (meth)acrylate; diethylene glycol monomethyl ether (meth)acrylate; diethylene glycol monoethyl ether (meth)acrylate; diethylene glycol monobutyl ether (meth)acrylate; triethylene glycol monoethyl ether (meth)acrylate; ethoxylated lauryl (meth)acrylate; methoxy polyethylene glycol (meth)acrylate; hydroxyethyl-butylcarbamate (meth)acrylate; 3-(2-hydroxyalkyl)oxazolidinone (meth)acrylate; and combinations thereof.

[0097] Other suitable examples of monofunctional (meth)acrylate monomers include, for example, caprolactone (meth)acrylate, 2-(2-ethoxyethoxy)ethyl (meth)acrylate, 2-phenoxyethyl (meth)acrylate, isooctyl (meth)acrylate, 2-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isodecanyl (meth)acrylate, ethoxyethoxyethyl (meth)acrylate, neopentyl glycol (meth)acrylate and their alkoxylated analogs, and caprolactone-based (meth)acrylates (“caprolactone adducts of (meth)hydroxyalkyl esters”) and combinations thereof prepared by adding one, two, three or more moles of caprolactone to a hydroxyalkyl (meth)acrylate, such as hydroxyethyl (meth)acrylate.

[0098] As described herein, (meth)acrylate monomers can be multifunctional. Multifunctional (meth)acrylate monomers can have 2 to 6 (meth)acrylate groups, particularly 2 or 3 (meth)acrylate groups. Examples of suitable multifunctional (meth)acrylate monomers include bisphenol A di(meth)acrylate; hydrogenated bisphenol A di(meth)acrylate; ethylene glycol di(meth)acrylate; diethylene glycol di(meth)acrylate; triethylene glycol di(meth)acrylate; tetraethylene glycol di(meth)acrylate; polyethylene glycol di(meth)acrylate; propylene glycol di(meth)acrylate; dipropylene glycol di(meth)acrylate; tripropylene glycol di(meth)acrylate; tetrapropylene glycol di(meth)acrylate; polypropylene glycol di(meth)acrylate; polytetramethylene glycol di(meth)acrylate. Esters; 1,2-Butanediol di(meth)acrylate; 2,3-Butanediol di(meth)acrylate; 1,3-Butanediol di(meth)acrylate; 1,4-Butanediol di(meth)acrylate; 1,5-Pentanediol di(meth)acrylate; 1,6-Hexanediol di(meth)acrylate; 1,8-Octanediol di(meth)acrylate; 1,9-Nonanediol di(meth)acrylate; 1,10-Nonanediol di(meth)acrylate; 1,12-Dodecanediol di(meth)acrylate; Neopentyl glycol di(meth)acrylate; Neopentyl glycol hydroxyneopentate dipropylene glycol Acrylates; 2-Methyl-2,4-pentanediol di(meth)acrylate; polybutadiene di(meth)acrylate; cyclohexane-1,4-diethanol di(meth)acrylate; tricyclodecanediethanol di(meth)acrylate; metal di(meth)acrylate; modified metal di(meth)acrylate; glyceryl di(meth)acrylate; glyceryl tri(meth)acrylate; trimethylolethane tri(meth)acrylate; trimethylolethane di(meth)acrylate; trimethylolpropane tri(meth)acrylate; trimethylolpropane di(meth)acrylate; pentaerythritol di(meth)acrylate Acrylates; pentaerythritol tri(meth)acrylates; pentaerythritol tetra(meth)acrylates; di(trimethylolpropane)diacrylates; difunctional ester diol diacrylates; di(trimethylolpropane)triacrylates; di(trimethylolpropane)tetraacrylates; sorbitol penta(meth)acrylates; di(pentaerythritol)tetraacrylates; di(pentaerythritol)pentaacrylates; di(pentaerythritol)hexa(meth)acrylates; tri(2-hydroxyethyl)isocyanurate tri(meth)acrylates; and their alkoxylated (e.g., ethoxylated and / or propoxylated) derivatives; and combinations thereof.

[0099] In one exemplary embodiment, the curable composition comprises a separate cationic curable monomer or as a component of a resin. In the cationic polymerization mechanism, a cationic initiator accepts a charge from a cationic curable compound, then becomes reactive and causes chain growth through reaction with another cationic curable compound.

[0100] In one exemplary embodiment, the curable composition comprises 1% to 75% by weight of a cationic curable compound or resin based on the total weight of the polymerizable components, for example, 1% to 65% by weight, for example, 1% to 55% by weight, for example, 1% to 45% by weight, for example, 1% to 35% by weight, for example, 1% to 25% by weight, for example, 1% to 15% by weight, for example, 5% to 75% by weight, for example, 5% to 65% by weight, for example, 5% to 55% by weight, for example, 5% to 45% by weight, for example, 5% to 35% by weight, for example, 5% to 25% by weight, for example, 5% to 15% by weight. For example, 10% to 75% by weight, for example, 10% to 65% by weight, for example, 10% to 55% by weight, for example, 10% to 45% by weight, for example, 10% to 35% by weight, for example, 10% to 25% by weight, for example, 15% to 75% by weight, for example, 15% to 65% by weight, for example, 15% to 55% by weight, for example, 15% to 45% by weight, for example, 15% to 35% by weight, for example, 20% to 75% by weight, for example, 20% to 65% by weight, for example, 20% to 55% by weight, for example, 30% to 75% by weight, for example, 30% to 65% by weight.

[0101] The cationic curable monomer can be selected from epoxides, oxetanes, vinyl ethers, vinylamides, oxetanes, cyclic acetals, cyclic lactones, thiohexacyclopropanes, thiohexacyclobutanes, spiro-orthoesters, olefinic unsaturated compounds other than (meth)acrylates, their derivatives, and mixtures thereof.

[0102] Epoxides can include aromatic epoxides, alicyclic epoxides, oxetanes, and mixtures thereof. Suitable epoxy-functionalized compounds capable of cationic polymerization include glycidyl ethers, particularly mono-, di-, tri-, and polyglycidyl ether compounds, and alicyclic ether compounds, including those containing carboxylic acid residues, such as alkyl carboxylic acid residues, alkylcycloalkyl carboxylic acid residues, and dialkyl dicarboxylic acid residues. For example, epoxy-functionalized compounds can be bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol S diglycidyl ether, brominated bisphenol A diglycidyl ether, brominated bisphenol F diglycidyl ether, brominated bisphenol S diglycidyl ether, epoxy phenolic varnish resin, hydrogenated bisphenol A diglycidyl ether, hydrogenated bisphenol F diglycidyl ether, hydrogenated bisphenol S diglycidyl ether, 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexane carboxylate, 2-(3,4'-epoxycyclohexane carboxylate, etc.) -Epoxycyclohexyl-5,5-spiro-3,4-epoxy)cyclohexane-1,4-dioxacyclohexane, bis(3,4-epoxycyclohexylmethyl) adipate, vinylcyclohexene oxide, limonene dioxide, bis(3,4-epoxy-6-methylcyclohexylmethyl) adipate, 3,4-epoxy-6-methylcyclohexyl-3',4'-epoxy-6'-methylcyclohexane carboxylate, methylene bis(3,4-epoxycyclohexane), dicyclopentadiene diepoxide ethylene glycol di(3,4-epoxycyclohexylmethyl) ether, ethylene bis(3,4-epoxycyclohexane carboxylate), epoxy hexahydrodioctyl phthalate, epoxy hexahydrodi-2-ethylhexyl phthalate, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerol triglycidyl ether, trimethylolpropane triglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, by incorporating aliphatic polyols such as ethylene glycol Polyether polyols obtained by adding one or more epoxides to propylene glycol and glycerol include polyglycidyl ethers, diglycidyl esters of aliphatic long-chain dicarboxylic acids, monoglycidyl ethers of aliphatic higher alcohols, phenol, cresol, butylphenol, or monoglycidyl ethers of polyether alcohols obtained by adding epoxides to these compounds, glycidyl esters of higher fatty acids, epoxidized soybean oil, epoxidized butyl stearic acid, epoxidized octyl stearic acid, epoxidized linseed oil, epoxidized polybutadiene, etc.

[0103] The cationic curable resin may include an epoxide resin, preferably a multifunctional (preferably bifunctional) epoxide resin.

[0104] Epoxides may include alicyclic epoxides. Cationic curable resins may contain difunctional epoxide monomers, such as difunctional alicyclic epoxide monomers. Difunctional alicyclic epoxide monomers may have structure 7.

[0105]

[0106] The cationic curable monomer may contain at least 80% by weight, for example, at least 90% by weight, at least 95% by weight, at least 99% by weight, or even at least 99.9% by weight, of an epoxide resin, based on the total weight of the cationic curable resin. The cationic curable resin may contain at least one epoxide monomer, be substantially composed of, or be composed of.

[0107] Suitable oxetane monomers that can be cationically curable include trimethylene oxide, 3,3-dimethyloxetane, 3,3-dichloromethyloxetane, 3-ethyl-3-phenoxymethyloxetane, bis(3-ethyl-3-methoxy)butane, and 3-ethyl-3-oxetanemethanol.

[0108] Suitable oxacyclopentanes capable of cationic polymerization include tetrahydrofuran and 2,3-dimethyltetrahydrofuran.

[0109] Suitable cyclic acetals capable of cationic polymerization include trioxane, 1,3-dioxane, and 1,3,6-trioxanecyclooctane.

[0110] Suitable cyclic lactones capable of cationic polymerization include β-propiolactone and ε-caprolactone.

[0111] Suitable thiohexacyclopropanes capable of cationic polymerization include cyclothioethanes, 1,2-propylidenes, and thio-representing chlorohydrins.

[0112] Suitable thioheterocyclic butanes capable of cationic polymerization include 3,3-dimethylthioheterocyclic butane.

[0113] Suitable spiro-orthoesters capable of cationic polymerization are compounds obtained through the reaction of epoxides and lactones.

[0114] Other suitable olefinically unsaturated compounds capable of cationic polymerization include vinyl ethers, such as ethylene glycol divinyl ether, triethylene glycol divinyl ether, and trimethylolpropane trivinyl ether; aliphatic vinyl monomers, such as vinylcyclohexane; olefins, such as isobutylene; dienes, such as butadiene; vinyl alkyl ethers; vinyl aromatic monomers, such as styrene and alkylstyrene; unsaturated polymers, such as polybutadiene; derivatives of the above organic substances; etc., at least some of which can also be polymerized via a free radical mechanism.

[0115] In one exemplary embodiment, the curable composition may contain at least one chain transfer agent, including but not limited to thiols, amines, or alcohols. In various embodiments, the curable composition may contain 0% to 45% by weight of one or more chain transfer agents based on the total weight of the polymerizable components.

[0116] In one exemplary embodiment, the curable composition further comprises one or more additives, including but not limited to UV blockers, pigments, dyes, stabilizers, inhibitors, antioxidants, UV absorbers, light stabilizers, foam inhibitors (defoamers), flow agents or leveling agents, colorants, dispersants, diluents, slip additives, fillers other than phosphorus-containing fillers described herein, thixotropic agents, matting agents, accelerators, adhesion promoters (e.g., acid adhesion promoters), tackifiers, polymers other than those described herein, waxes, or various other additives, including any additives conventionally used in coatings, sealants, adhesives, inks, or flame-retardant coatings.

[0117] In various embodiments, the curable composition may comprise one or more of these additives in amounts from 0% to 20% by weight based on the total weight of the polymerizable components, such as 0.01% to 20% by weight, such as 0.01% to 10% by weight, such as 0.01% to 5% by weight, such as 0.01% to 1% by weight, such as 0.1% to 20% by weight, such as 0.1% to 10% by weight, such as 0.1% to 5% by weight, such as 0.1% to 1% by weight, such as 0.5% to 20% by weight, such as 0.5% to 10% by weight, such as 0.5% to 5% by weight, such as 0.5% to 1% by weight.

[0118] Preparation of the composition

[0119] When the curable composition contains at least one cationic curable monomer (e.g., a component in a resin), a cationic photoinitiator is also present. Cationic photoinitiators are typically salts, such as onium salts, such as iodonium salts, sulfonium salts, pyridinium salts, alkoxypyridinium salts, phosphonium salts, oxonium salts, or diazonium salts. In embodiments, the cationic photoinitiator may comprise sulfonium salts, iodonium salts, and / or other onium salts. Specifically, the cationic photoinitiator may be an onium salt, such as a diaryliodonium salt and / or a triarylsulfonium salt. Such cationic photoinitiators include sulfonium salts. Among the sulfonium salts are aromatic sulfonium salts. Specific examples include triphenylsulfonium salts, methyl diphenylsulfonium salts, dimethylphenylsulfonium salts, diphenylnaphthylsulfonium salts, and di(methoxy-naphthyl)methylsulfonium salts. Such aromatic sulfonium salts include those containing hexafluorophosphate ions (PF6). - ) or hexafluoroantimonate ion (SbF6) - Aromatic sulfonium salts as counterions. Specific examples include triphenylsulfonium hexafluorophosphate, methyl diphenyl-sulfonium hexafluorophosphate, dimethylphenyl-sulfonium hexafluorophosphate, diphenylnaphthyl-sulfonium hexafluorophosphate, di(methoxynaphthyl)methyl-sulfonium hexafluorophosphate, and triarylsulfonium hexafluoroantimonate (e.g., Speedcure 976).

[0120] Cationic photoinitiators may comprise triarylsulfonium salts, such as (thioalkyldiphenyl-4,1-diyl)bis(diphenylsulfonium)bis(hexafluoroantimonate). Triarylsulfonium salts may comprise compounds with structures 8, 9, or both. Suitable triarylsulfonium-based cationic photoinitiators are available from Sartamomer under the trademark Speedcure™ 976.

[0121]

[0122] In an embodiment, based on the total weight of the cationic photoinitiator, the cationic photoinitiator may contain at least 80% by weight, such as at least 90% by weight, such as at least 95% by weight, such as at least 99% by weight, such as at least 99.9% by weight, of an onium salt, such as a sulfonium salt. The cationic photoinitiator may contain, consist of, or be substantially composed of at least one onium salt.

[0123] The cationic photoinitiator may optionally be coupled to the photosensitive compound. Without being theoretically limited, certain radical photoinitiators can act as reducing agents when photoexcited to interact with the cationic photoinitiator (e.g., iodonium salt) in a redox reaction. The resulting oxidative radical photoinitiator is then a cation that can directly initiate cationic polymerization or interact with other components in the formulation to generate an active cation capable of initiating cationic photopolymerization. In embodiments, the photosensitive compound may be a radical photoinitiator sensitive to photochemical radiation. In embodiments, the radical photoinitiator may be a Norrish type I photoinitiator. Examples of such type I photoinitiators include, but are not limited to, Speedcure TPO, Speedcure BKL (Irgacure 651), and Speedcure BPO (BAPO). In other embodiments, the free radical photoinitiator may be selected from various Norrish type II photoinitiators, such as xanthones, thioxanthone, isopropylthioxanthone, chloropropoxythioxanthone, diethylthioxanthone, benzophenone, and acetophenone, or derivatives thereof, provided that the photosensitizer absorbs at the desired wavelength. In embodiments, the cationic photoinitiator may be an iodonium salt, and the free radical photoinitiator may be selected from xanthones, thioxanthone, isopropylthioxanthone, chloropropoxythioxanthone, diethylthioxanthone, benzophenone, acetophenone, acylphosphine oxide, or derivatives thereof.

[0124] Suitable iodonium salts may be selected from bis(4-dodecylphenyl)iodonium hexafluoroantimonate (structure 10); bis-(4-tert-butylphenyl)iodonium hexafluorophosphate (structure 11); and 4-isopropyl-4'-methyldiphenyliodonium tetra(pentafluorophenyl)borate (structure 12). Suitable commercially available bis(4-dodecylphenyl)iodonium hexafluoroantimonate of structure 10 can be branded under the name Speedcure. TM937 was purchased from Sartomer. Suitable commercially available bis-(4-tert-butylphenyl)-iodonium hexafluorophosphate of structure 11 is available under the trademark Speedcure. TM 938 was purchased from Sartomer. Suitable commercially available 4-isopropyl-4'-methyldiphenyliodonium tetra(pentafluorophenyl)borate of structure 12 is marketed under the trademark Speedcure. TM Purchased from Sartomer for 939.

[0125]

[0126] Photochemical radiation may include ultraviolet (UV) light, such as light in the UVB and UVC range, for example, light with wavelengths from 180 nm to 400 nm, such as 200 nm to 400 nm or 200 nm to 320 nm. In an embodiment, the photochemical radiation range may be generated by a mercury lamp, such as an H lamp.

[0127] The curable composition is substantially free of any halogen atoms and therefore contains less than 2% by weight, for example less than 1% by weight, for example less than 0.5% by weight, for example less than 0.2% by weight, for example 0 to 2% by weight, for example 0 to 1% by weight, for example 0 to 0.5% by weight, for example 0% by weight, relative to the total weight of the polymerizable components.

[0128] In one exemplary embodiment, the curable composition is a liquid dispersion at room temperature (25°C). Specifically, at room temperature, the curable composition may be in the form of a plurality of solid phosphorus-containing filler particles dispersed in a liquid phase, said liquid phase comprising at least a portion of the polymerizable component of the curable composition.

[0129] In one exemplary embodiment, the curable composition comprises less than 5% by weight of a reactive flame retardant, for example less than 3% by weight, for example less than 1% by weight, for example less than 0.3% by weight, for example 0 to less than 5% by weight, for example 0 to 3% by weight, for example 0 to 1% by weight, for example 0% by weight of a reactive flame retardant, relative to the total weight of the polymerizable components. For clarification, the term "reactive flame retardant" as used herein does not include isocyanurates as described herein.

[0130] In one exemplary embodiment, the curable composition comprises less than 5% by weight of polyamide-forming monomers, for example less than 3% by weight, for example less than 1% by weight, for example less than 0.3% by weight, for example 0 to less than 5% by weight, for example 0 to 3% by weight, for example 0 to 1% by weight, for example 0% by weight of polyamide-forming monomers, relative to the total weight of the polymerizable components. As used herein, the term polyamide-forming monomers encompasses amino acids, diacids, and diamines.

[0131] This disclosure includes photocurable compositions comprising products obtained by photocuring curable compositions as described herein. The curable compositions can be cured by exposing them to photochemical radiation and optionally by heating.

[0132] use

[0133] The curable compositions described herein can be used in moldings and coatings.

[0134] The curable compositions described herein can also be used as 3D printing compositions and in 3D printing processes.

[0135] A curable composition can be partially cured during the 3D printing process to form a green composition. As described below, the green composition can then be post-cured to form a post-cured composition. It should be understood that the cured composition may include both the green composition and the post-cured composition. Therefore, curable compositions can be used to construct 3D printed articles, which may contain a curable composition, a green composition, a post-cured composition, or a combination thereof.

[0136] Methods for preparing 3D printed articles may include curing the photocurable composition. Specifically, the curable composition may be cured by exposing it to photochemical radiation. In particular, the photochemical radiation may include UV, near-UV, visible light, infrared and / or near-infrared radiation, or electron beam radiation.

[0137] 3D printed articles can be obtained using methods for preparing 3D printed articles, including printing 3D printed articles with curable compositions as described herein. In particular, the method may include printing 3D printed articles layer by layer or continuously.

[0138] Multiple layers of the curable composition as described herein can be applied to a substrate surface; the multiple layers can be cured simultaneously (e.g., by exposure to a single dose of radiation), or each layer can be cured sequentially before the application of another layer of the curable composition. In some embodiments, each layer can be cured sequentially before the application of another layer, and then multiple layers can be cured simultaneously.

[0139] The curable compositions described herein can be used as resins in 3D printing applications. 3D printing (also known as additive manufacturing) is the process of creating 3D digital models by building up material. 3D printed objects are created by sequentially constructing two-dimensional (2D) layers or slices corresponding to the cross-sections of the object using computer-aided design (CAD) data. Stereolithography (SL) is a type of additive manufacturing in which liquid resin is selectively exposed to radiation to form each 2D layer. The radiation can be in the form of electromagnetic waves or electron beams. The most commonly used energy sources are ultraviolet, visible, or infrared radiation.

[0140] Suitable 3D printing processes may include digital light printing (DLP), stereolithography (SLA), inkjet printing, multijet printing, piezoelectric printing, photocurable extrusion, liquid crystal display (LCD) printing, and gel deposition printing, as well as any combination of these.

[0141] Stereolithography and other photocurable 3D printing methods typically apply a low-intensity light source to irradiate each layer of a curable composition to form a desired article containing a green composition. Therefore, the polymerization kinetics, green strength, and homopolymer volume shrinkage rate of the photocurable composition during curing are important criteria for determining whether a particular curable composition will fully polymerize (cur) upon irradiation and have sufficient print fidelity for its intended purpose.

[0142] The desired article containing the green composition can then be exposed to an additional dose of photochemical radiation in a process known as post-curing. Post-curing the article containing the green composition produces an article containing the post-cured composition.

[0143] The curable compositions described herein are particularly useful as 3D printing resin formulations, i.e., compositions intended for the manufacture of three-dimensional articles using 3D printing technology. Such three-dimensional articles can be self-supporting / self-supporting and can comprise, consist essentially of, or be composed of the compositions described herein, regardless of whether the curable composition has been cured. The three-dimensional articles can also be composite materials comprising at least one component that is substantially composed of or consists of the cured composition as described above, and at least one additional component comprising one or more materials different from such cured compositions (e.g., metallic or thermoplastic components, inorganic fillers, or fiber reinforcements). The curable compositions described herein can be used in 3D printing operations with another material that serves as a support or scaffold for the article formed from the curable compositions described herein.

[0144] Therefore, the curable compositions described herein can be used to practice various types of three-dimensional manufacturing or printing techniques, including methods in which three-dimensional objects are constructed in a step-by-step or layer-by-layer manner. In such methods, layer formation can be achieved by solidifying (curing) the curable composition upon exposure to radiation (e.g., visible light, UV, or other photochemical radiation). For example, a new layer can be formed at the top surface or the bottom surface of the grown object. The curable compositions described herein can also be advantageously used in methods of producing three-dimensional objects by additive manufacturing, wherein the method is carried out continuously. For example, the object can be produced by a liquid interface. Suitable methods of this type are sometimes referred to in the art as “continuous liquid interface (or phase-to-phase) product (or printing)” (“CLIP”) methods. Such methods are described, for example, in WO 2014 / 126830; WO 2014 / 126834; WO 2014 / 126837; and Tumbleston et al., “Continuous Liquid Interface Production of 3D Objects”, Science 347(6228), 1349-1352 (2015), all of which are incorporated herein by reference in their entirety for all purposes.

[0145] When stereolithography is performed above an oxygen-permeable building window, articles can be produced using curable compositions as described herein by creating an oxygen-containing “dead zone” in the CLIP process. This dead zone is a thin, uncured layer of the curable composition between the window and the surface of the cured article being produced. In this method, a curable composition is used in which curing (polymerization) is inhibited by the presence of molecular oxygen; this inhibition is typically observed in curable compositions, for example, those capable of curing via a free radical mechanism. The desired dead zone thickness can be maintained by selecting various control parameters, such as photon flux and the optical and curing properties of the curable composition. The CLIP process is performed by projecting a continuous sequence of photochemical radiation (e.g., UV) images (e.g., which may be generated by a digital light processing imaging unit) through an oxygen-permeable, photochemical radiation (e.g., UV) transparent window held beneath a bath of curable composition in liquid form. The liquid interface beneath the advancing (growing) article is maintained by the dead zone created above the window. The cured article is continuously extracted from a curable composition bath above the dead zone. The dead zone can be replenished by feeding additional amounts of curable composition into the bath to compensate for the amount of curable composition that has been cured and incorporated into the grown article.

[0146] In another embodiment, the curable composition can be supplied by jetting it from the printhead rather than from a barrel. This type of process is commonly referred to as inkjet or multijet 3D printing. One or more UV curing sources mounted directly behind the inkjet printhead cure the curable composition immediately after it is applied to the build surface substrate or a previously applied layer. Two or more printheads can be used in this method, allowing different compositions to be applied to different areas of each layer. For example, compositions of different colors or different physical properties can be applied simultaneously to produce 3D printed parts with different compositions. In typical use, a support material (which is subsequently removed during post-processing) is deposited simultaneously with the composition used to produce the desired 3D printed part. The printhead can operate at temperatures from about 25°C to about 100°C. At the operating temperature of the printhead, the viscosity of the curable composition is less than 30 mPa⁻².

[0147] Methods for preparing 3D printed articles may include the following steps:

[0148] a) Providing (e.g., coating) a first layer of the curable composition as described herein onto a surface;

[0149] b) Curing the first layer at least partially to provide a cured first layer;

[0150] c) Provide (e.g., coat) a second layer of the curable composition as described herein onto the cured first layer;

[0151] d) Curing the second layer at least partially to provide a cured second layer that adheres to the cured first layer; and

[0152] e) Repeat steps c) and d) as desired to build the 3D printed article.

[0153] Methods for preparing 3D printed articles may include the following steps:

[0154] a) Providing (e.g., coating) a first layer of a curable composition in liquid form as described herein onto a surface;

[0155] b) Expose the first layer to photochemical radiation in an image-wise manner to form an image cross-section of the first exposure, wherein the photochemical radiation has sufficient intensity and duration to cause at least partial curing of the layer in the exposed area;

[0156] c) Provide (e.g., coat) an additional layer of the curable composition as described herein onto the previously exposed imaging cross section;

[0157] d) Expose the additional layer to photochemical radiation in an imaging manner to form an additional imaging cross section, wherein the photochemical radiation has sufficient intensity and duration to cause at least partial curing of the additional layer in the exposed area and to cause the additional layer to adhere to the previously exposed imaging cross section.

[0158] e) Repeat steps c) and d) as desired to build the 3D printed article.

[0159] Either of the above two methods may further include step f) exposing the 3D-printed article to photochemical radiation, wherein the photochemical radiation has sufficient intensity and duration to cure at least 50 wt%, at least 60 wt%, at least 70 wt%, at least 80 wt%, at least 90 wt%, at least 95 wt%, or even at least 99 wt% of the polymerizable components in the curable composition, based on the total weight of the polymerizable components in the curable composition. All or part of the 3D-printed article may be exposed to photochemical radiation.

[0160] While the curing step can be performed in any suitable manner, which in some cases will depend on the components present in the curable composition, in certain embodiments of this disclosure, curing is accomplished by exposing the layer to be cured to an effective amount of radiation (particularly photochemical radiation). Photochemical radiation may include, for example, electron beam radiation, UV radiation, and visible light radiation. The 3D printed article can be heat-formed to achieve thermosetting.

[0161] After a 3D printed article has been printed, it may undergo one or more post-processing steps. Post-processing steps may be selected from one or more of the following: removal of any printed support structures, washing with water and / or organic solvents to remove residual resin, and post-curing simultaneously or sequentially using heat treatment and / or photochemical radiation. Post-processing steps can be used to transform a newly printed article into a finished functional article ready for its intended application.

[0162] In some embodiments of one or more post-processing steps, curing can be accelerated or promoted by providing energy to the curable composition, for example by heating the curable composition. Photocurable compositions can be cured by exposure to photochemical radiation, wherein further curing is achieved by heating the partially cured article. For example, articles formed from curable compositions (e.g., 3D printed articles) can be heated at temperatures from 40°C to 250°C for periods ranging from 5 minutes to 12 hours.

[0163] 3D printed articles may contain curable compositions as described herein. Upon curing, 3D printed articles may contain photocurable compositions as described herein. It should be understood that some portions of a 3D printed article may contain curable compositions, while other portions of the same article may contain photocurable compositions.

[0164] The invention is illustrated by the following non-limiting examples.

[0165] Example

[0166] abbreviations

[0167] SR368-Tris(2-hydroxyethyl)isocyanurate triacrylate

[0168] SR533-1,3,5-tris-2-propenyl-1,3,5-triazine-2,4,6(1H,3H,5H)-trione

[0169] SR606A - Neopentyl glycol hydroxyneopentate diacrylate

[0170] TEMPIC-tris[(3-mercaptopropionyloxy)-ethyl]-isocyanurate

[0171] TPO–L-phenyl(2,4,6-trimethylbenzoyl)phosphine ethyl ester

[0172] OP945 - Organic Phosphate Granules

[0173] AP423-Inorganic Phosphate Granules

[0174] TEP-triethyl phosphate

[0175] OB+-2,2'-(2,5-thiophenediyl)-bis(5-tert-butylbenzoxazole)

[0176] BYK-1799 - Contains Si surface additives

[0177] Q1301-N-Nitrophenylhydroxylamine aluminum salt

[0178] MeHQ–4-methoxyphenol

[0179] TBC-4-tert-butylcatechol

[0180] HQ – Hydroquinone

[0181] Preparation of the curable composition of the present invention

[0182] The curable compositions from Tables 1 and 2 were prepared as follows: 200 g of liquid resin was prepared by combining the listed components in the amounts described in their respective tables and stirring them at 65°C for 1–3 hours using a magnetic stirring plate. Once all components were fully mixed, the resin was cooled, and solid fillers were added and thoroughly mixed using a high-shear blade and an overhead vertical mixer.

[0183] Table 1

[0184]

[0185] Table 2

[0186]

[0187] UL-94 FR test

[0188] The UL-94 rating of compositions that pass the stability test is evaluated according to the UL-94 standard for vertical burning tests. Full details of the test method can be found in Section 8 of the UL-94 standard. However, only a summary of the method is given here for illustrative purposes: The test uses a rectangular specimen with dimensions of 125±5 mm × 13±0.5 mm. The long axis of the test specimen is oriented vertically, and a cotton indicator is placed below the specimen. The bottom of the specimen is ignited with a Bunsen burner for 10 seconds. After the flame is removed, the time it takes for the specimen to extinguish is recorded. After extinguishing, the sample is reignited for 10 seconds. After the flame is removed, the time required for the specimen to extinguish a second time and the time for the afterglow to cease are recorded. The flame retardancy of the materials is classified using the standards in Table 8.1 of the UL-94 standard. The UL-94 results for the compositions in Tables 1 and 2 are summarized in Table 3, where V-0 is the best possible classification for the tested compositions under the UL-94 standard for vertical burning tests, and "NR" indicates "no rating".

[0189] Table 3

[0190]

[0191] Filler leaching through mass loss test

[0192] The UL-94 bars were cured using the desired composition and weighed on the same day. The bars were then placed in an 80°C oven for 14 days and the mass loss relative to their initial weight was weighed. The results are shown in Table 4.

[0193] Table 4

[0194]

[0195] Table 4 illustrates the advantageous effects of solid phosphorus-containing fillers (e.g., OP945 or AP423) compared to liquid phosphorus-containing fillers (e.g., TEP). No mass loss was expected in any of the samples from Table 4. Samples 8, 9, 12, and 13 each contained solid phosphorus-containing fillers, and the liquid phosphorus-containing filler (TEP) in sample 11 had a boiling point of 215°C, significantly lower than the 80°C at which this study was conducted. However, sample 11 showed significant mass loss after 24 hours and 14 days at 80°C compared to the unfilled control material (composition 10). No significant mass loss was observed in the other samples compared to the unfilled control material. The mass loss in sample 11 indicates the loss of FR filler. Loss of FR filler in these materials, whether over time or upon exposure to heat, leads to reduced flame retardancy and the production of defective materials. Regardless of boiling point, it is advantageous to use solid flame retardant fillers instead of liquid flame retardant fillers to ensure the flame retardant life of these materials.

[0196] The invention described herein is intended to cover not only all aspects or exemplary embodiments of the invention, but also all combinations of aspects and embodiments.

Claims

1. A curable composition comprising, substantially consisting of, or consisting of the following: - At least 25% by weight of at least one isocyanurate-containing monomer having at least one (meth)acrylate group, based on the total weight of the polymerizable components; - At least 5% by weight of a phosphorus-containing non-reactive filler based on the total weight of the polymerizable components, wherein the filler is in solid form at room temperature and contains at least 10% by weight of phosphorus; and - Free radical photoinitiator The composition described therein contains virtually no halogens.

2. The curable composition according to claim 1, wherein the composition is a liquid dispersion at room temperature.

3. The curable composition according to claim 1 or 2, wherein the composition contains less than 5% by weight of a reactive flame retardant based on the total weight of the polymerizable components.

4. The curable composition according to any one of claims 1 to 3, wherein the phosphorus-containing non-reactive filler is in particulate form.

5. The curable composition according to any one of claims 1 to 4, wherein the at least one isocyanurate-containing monomer has at least two (meth)acrylate groups.

6. The curable composition according to any one of claims 1 to 5, wherein the at least one isocyanurate-containing monomer has at least three (meth)acrylate groups.

7. The curable composition according to any one of claims 1 to 6, wherein the curable composition comprises 30% to 90% by weight of at least one isocyanurate-containing monomer having at least one (meth)acrylate group.

8. The curable composition according to any one of claims 1 to 7, wherein the phosphorus-containing filler is a phosphonate or phosphonate filler.

9. The curable composition according to any one of claims 1 to 8, wherein the phosphorus-containing filler is a phosphonate or phosphonate filler.

10. The curable composition according to any one of claims 1 to 9, wherein the phosphorus-containing filler is a phosphate or phosphate ester filler.

11. The curable composition according to any one of claims 1 to 10, wherein the phosphorus-containing filler is an inorganic phosphate filler.

12. The curable composition according to any one of claims 1 to 11, wherein the phosphorus-containing filler comprises polyphosphates, particularly ammonium polyphosphates, dialkylphosphinates, particularly aluminum diethylphosphinate, red phosphorus, melamine phosphate, phosphates, solid trialkyl phosphates, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, cyclic phenoxyphosphazenes, solid phosphoramides, melamine polyphosphate, cyclic phosphonates, phosphorus nitrogen oxide radicals, phosphine oxides, and mixtures thereof.

13. The curable composition according to any one of claims 1 to 12, wherein the curable composition comprises at least one non-reactive phosphorus-containing filler at a weight percentage of 8% to 75% based on the total weight of the polymerizable components.

14. The curable composition according to any one of claims 1 to 12, wherein the curable composition comprises at least one non-reactive phosphorus-containing filler at a weight percentage of 15% to 75% based on the total weight of the polymerizable components.

15. The curable composition according to any one of claims 1 to 14, further comprising at least one non-acrylic isocyanurate-containing monomer.

16. The curable composition of claim 15, wherein the non-acrylic isocyanurate-containing monomer has at least one allyl group.

17. The curable composition of claim 15, wherein the non-acrylic isocyanurate-containing monomer has at least two allyl groups.

18. The curable composition of claim 15, wherein the non-acrylic isocyanurate-containing monomer has at least three allyl groups.

19. The curable composition according to claim 15, wherein the non-acrylic isocyanurate-containing monomer has at least one thiol group.

20. The curable composition of claim 15, wherein the non-acrylic isocyanurate-containing monomer has at least two thiol groups.

21. The curable composition of claim 15, wherein the non-acrylic isocyanurate-containing monomer has at least three thiol groups.

22. The curable composition according to claim 15, wherein a non-acrylic isocyanurate monomer having at least one allyl group and a non-acrylic isocyanurate monomer having at least one thiol group are both present in the composition.

23. The curable composition according to any one of claims 1 to 22, further comprising at least one olefinic unsaturated monomer and / or oligomer without isocyanurate groups.

24. The curable composition according to claim 23, wherein the olefinic unsaturated monomer and / or oligomer has at least one (meth)acrylate group.

25. The curable composition according to any one of claims 1 to 24, further comprising at least one cationic curable monomer.

26. The curable composition according to any one of claims 1 to 25, further comprising at least one cationic curable resin.

27. The curable composition of claim 25, wherein the cationic curable monomer has at least one epoxy group.

28. The curable composition of claim 25, wherein the cationic curable monomer has at least one oxobutyryl group.

29. The curable composition according to claim 26, wherein the cationic curable resin is an epoxy resin.

30. The curable composition according to claim 26, wherein the cationic curable resin is an oxobutane resin.

31. The curable composition according to any one of claims 1 to 30, further comprising a wetting agent.

32. The curable composition according to any one of claims 1 to 31, further comprising one or more ultraviolet blocking agents, pigments, dyes, stabilizers, inhibitors, antioxidants, ultraviolet absorbers, light stabilizers, foam inhibitors, flow agents or leveling agents, colorants, dispersants, diluents, slip additives, fillers other than phosphorus-containing fillers described herein, thixotropic agents, matting agents, accelerators, adhesion promoters, tackifiers, polymers other than those described herein, and waxes.

33. A partially cured composition formed from a curable composition according to any one of claims 1 to 32.

34. A cured composition formed from the curable composition according to any one of claims 1 to 32.

35. The cured composition according to claim 34, having a UL 94 rating of V-2 or better.

36. The cured composition according to claim 34, having a UL 94 rating of V-1 or better.

37. The cured composition according to claim 34, having a UL 94 rating of V-0.

38. An article comprising a curable composition according to any one of claims 1 to 32 or a cured composition according to any one of claims 34 to 37.

39. A three-dimensional printed article formed from a curable composition according to any one of claims 1 to 32, or comprising a partially cured composition according to claim 33, or comprising a cured composition according to any one of claims 34 to 37.

40. A method for increasing the flame retardancy of an article, comprising coating at least one surface of the article with a curable composition according to any one of claims 1-32.

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