Flame-retardant build materials and related printed 3D articles

Abstract

Described herein are polymerizable liquids for 3D printing applications that, in some embodiments, impart flame retardancy and / or flame resistance to articles printed from the build material. The polymerizable liquid can also impart desirable mechanical properties to the article. In some embodiments, the polymerizable liquid includes a curable isocyanurate component in an amount of at least 20% by weight, based on the total weight of the polymerizable liquid, and an organophosphate component including one or more organophosphate compounds. In some embodiments, the polymerizable liquid further includes an acrylate component.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority pursuant to 35 U.S.C. Section 119 of U.S. Provisional Patent Application No. 63 / 123,739, filed December 10, 2020, which is incorporated by reference in its entirety. [Technical field]

[0002] The present invention relates to three-dimensional building materials, and in particular to polymerizable liquids that impart flame retardant or flame resistant properties to articles printed from the polymerizable liquid. [Background technology]

[0003] 3D printers use build materials, also known as inks, to form various 3D objects, articles, or parts according to computer-generated files. In some examples, the build materials are solid at ambient temperatures and turn into liquids at elevated jetting temperatures. In other examples, the build materials are liquids at ambient temperatures.

[0004] The build material can include a variety of chemical species. The choice of chemical species included in the build material can be selected according to various considerations, including, but not limited to, the desired chemical and / or mechanical properties of the printed article and the operating parameters of the 3D printing device. For example, ultraviolet (UV) curable acrylate formulations can generally print parts at high resolution in DLP systems. However, often the resulting parts lack the desired mechanical properties and are prone to breakage or other degradation pathways. Such degradation pathways impair the performance of the article and lead to premature failure. Summary of the Invention [Problem to be solved by the invention]

[0005] Additionally, some build materials and the resulting articles printed therefrom may be unsuitable for other applications requiring high temperature and / or flame resistance, and as a result, 3D printing techniques may have limited application in fields requiring flame retardant or flame resistant materials and articles. [Means for solving the problem]

[0006] In view of the above, polymerizable liquids for 3D printing applications are described herein, which in some embodiments impart flame retardant and / or flame resistant properties to articles printed from the liquid, including when such polymerizable liquids are used as build materials or inks. The polymerizable liquid may also impart desirable mechanical properties to the article. In some embodiments, the polymerizable liquid comprises a curable isocyanurate component in an amount of at least 20% by weight, based on the total weight of the polymerizable liquid, and an organophosphate component comprising one or more organophosphate compounds. In some embodiments, the polymerizable liquid further comprises an acrylate component. The acrylate component may comprise an acrylate monomer, an acrylate oligomer, or a mixture thereof.

[0007] Further described herein is a method of printing a three-dimensional article. In some embodiments, the method includes providing a polymerizable liquid including a curable isocyanurate component in an amount of at least 20% by weight, based on the total weight of the polymerizable liquid, and an organophosphate component including one or more organophosphate compounds. The polymerizable liquid is printed and cured to form an article. In some embodiments, the article is formed via a layer-by-layer process, where the layer formation is performed via deposition and curing of a layer of the polymerizable liquid. In some embodiments, the polymerizable liquid also includes an acrylate component. The acylate component can include an acrylate monomer, an acrylate oligomer, or a mixture thereof.

[0008] As further described herein, the polymerizable liquid may further include a photoinitiator component, and curing of the polymerizable liquid may occur by irradiation of the liquid with light of an appropriate wavelength to initiate free radical polymerization.

[0009] These and other embodiments are further described in the detailed description that follows. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The embodiments described herein can be more easily understood by referring to the following detailed description and examples. However, the elements, devices, and methods described herein are not limited to the specific embodiments presented in the detailed description and examples. It should be recognized that these embodiments are merely illustrative of the principles of the present invention. Many modifications and adaptations will be readily apparent to those skilled in the art without departing from the spirit and scope of the present invention.

[0011] Moreover, all ranges disclosed herein should be understood to encompass any and all subranges subsumed therein. For example, a stated range of "1.0 to 10.0" should be considered to include any and all subranges beginning with a minimum value equal to or greater than 1.0 and ending with a maximum value equal to or less than 10.0, such as 1.0 to 5.3, or 4.7 to 10.0, or 3.6 to 7.9.

[0012] All ranges disclosed herein should also be considered to include the endpoints of the range, unless otherwise specifically stated. For example, the range "between 5 and 10" should generally be considered to include the endpoints 5 and 10.

[0013] Additionally, when the phrase "up to" is used in connection with an amount or quantity, it is understood that the amount is at least the detectable amount or quantity. For example, a substance present in an amount "up to" a particular amount can be present in an amount from the detectable amount up to and including the particular amount.

[0014] The articles "a" or "an" are also understood to refer to "at least one," unless the context of a particular usage requires otherwise.

[0015] Terms like "3D printing system," "3D printer," "printing," and the like generally describe various solid freeform manufacturing techniques for creating three-dimensional articles or objects by selective deposition, jetting, fused deposition modeling, multi-jet modeling, and other additive manufacturing techniques now or that may become known in the art that use build materials or inks to produce three-dimensional objects.

[0016] definition The term "alkyl" as used herein, alone or in combination, refers to a straight or branched chain saturated hydrocarbon group, optionally substituted with one or more substituents. For example, alkyl is any of C1 to C6. 30 Or C1~C 18 where the subscript refers to the number of carbon atoms.

[0017] The term "alkenyl," as used herein, alone or in combination, refers to a straight-chain or branched-chain hydrocarbon group having at least one carbon-carbon double bond and optionally substituted with one or more substituents.

[0018] The term "alkynyl," as used herein, alone or in combination, refers to a straight-chain or branched-chain hydrocarbon group having at least one carbon-carbon triple bond and optionally substituted with one or more substituents.

[0019] The term "aryl", as used herein, alone or in combination, refers to an aromatic monocyclic or polycyclic ring system optionally substituted with one or more ring substituents.

[0020] The term "heteroaryl," as used herein, alone or in combination, refers to an aromatic monocyclic or polycyclic ring system in which one or more of the ring atoms is an element other than carbon, such as nitrogen, boron, oxygen and / or sulfur.

[0021] The term "heterocycle", as used herein, alone or in combination, refers to a monocyclic or polycyclic ring system in which one or more atoms of the ring system are elements other than carbon, such as boron, nitrogen, oxygen and / or sulfur or phosphorus, and the ring system is optionally substituted with one or more ring substituents. Heterocyclic ring systems can include aromatic and / or non-aromatic rings, including rings with one or more points of unsaturation.

[0022] The term "heteroalkyl," as used herein, alone or in combination, refers to an alkyl moiety as defined above having one or more carbon atoms, e.g., 1, 2, or 3 carbon atoms, substituted with one or more heteroatoms, which may be the same or different.

[0023] The term "heteroalkenyl," as used herein, alone or in combination, refers to an alkenyl moiety as defined above having one or more carbon atoms, e.g., 1, 2, or 3 carbon atoms, substituted with one or more heteroatoms, which may be the same or different.

[0024] The term "cycloalkyl," as used herein, alone or in combination, refers to a non-aromatic, monocyclic or polycyclic ring system optionally substituted with one or more ring substituents.

[0025] In one aspect, a polymerizable liquid is described herein for use in 3D printing applications.The polymerizable liquid can be used in digital light processing (DLP), stereolithography (SLA), and multi-jet printing (MJP) printing applications, for example, in some embodiments.The polymerizable liquid comprises a curable isocyanurate component in an amount of at least 20% by weight based on the total weight of the polymerizable liquid, and an organophosphate component comprising one or more organophosphate compounds.

[0026] Turning now to specific components, the curable isocyanurate component can include any curable isocyanurate not inconsistent with the technical objectives described herein, in some embodiments, the curable isocyanurate comprises one or a mixture of isocyanurate species.

[0027] The curable isocyanurate includes at least one moiety or functional group operable to participate in a polymerization process. In some embodiments, the isocyanurate can include multiple polymerizable moieties or functional groups. For purposes of reference herein, a "polymerizable moiety" includes a moiety that can be polymerized or cured to provide a printed 3D article or object. Such polymerization or curing can be performed in any manner not inconsistent with the objectives of this disclosure. The polymerizable moiety or functional group can include, for example, one that is operable to undergo a non-radiation induced polymerization mechanism, including polycondensation or reaction between an isocyanate and a hydroxyl. In some embodiments, the curable isocyanurate can include one or more reactive functional groups, including, but not limited to, epoxy, amine, and thiol. Alternatively, the one or more polymerizable functional groups can include one or more unsaturated points suitable for free radical polymerization. The isocyanurate, in some embodiments, is an isocyanurate acrylate or isocyanurate polyacrylate. In some embodiments, the isocyanurate polyacrylate can be represented by Formula I: [ka] The In the formula, R 1 ~R 3 are each independently selected from the group consisting of hydrogen and alkyl, and m, n, and p are each independently an integer ranging from 1 to 10.

[0028] In some embodiments, the isocyanurate is an allyl isocyanurate, such as polyallyl isocyanurate, which in some embodiments has the formula II: [ka] The In the formula, m, n, and p are independently integers ranging from 1 to 10.

[0029] In some embodiments, the curable isocyanurate is present in an amount of 30 to 80 weight percent or 35 to 70 weight percent based on the total weight of the polymerizable liquid.

[0030] In addition to the curable isocyanurate component, the polymerizable liquid includes an organophosphate component that includes one or more organophosphate compounds. Any organophosphate compatible with imparting flame retardant or flame resistant properties to the polymerizable liquid and articles printed from the polymerizable liquid can be used.

[0031] In some embodiments, the one or more organophosphate compounds correspond to Formula III: [ka] In the formula, R 1 ~R 3are each independently selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, heteroalkyl, heteroalkenyl, heterocyclyl, aryl, and heteroaryl. In some embodiments, for example, the one or more organophosphate compounds include aryl phosphate or heteroaryl phosphate. The aryl phosphate can, in some embodiments, include triphenyl phosphate. Additionally, in some embodiments, the one or more phosphate salts include bis(organophosphate). The bis(organophosphate) can, in some embodiments, include resorcinol bis(diphenyl phosphate), bisphenol A bis(diphenyl phosphate), or mixtures thereof.

[0032] The organophosphate compound of the polymerizable liquid is in some embodiments non-halogenated, for example, with fluorine, chlorine, or bromine.

[0033] The organophosphate component can be present in the polymerizable liquid in any desired amount, hi some embodiments, the organophosphate component is present in an amount of 10 to 40 weight percent or 20 to 40 weight percent, based on the total weight of the polymerizable liquid.

[0034] As described herein, the polymerizable liquid can further include an acrylate component in addition to the curable isocyanurate and organophosphate components. The acrylate component can include one or a mixture of photopolymerizable acrylate species. In some embodiments, for example, the acrylate component can include an acrylate monomer, an acrylate oligomer, or a mixture thereof. As known to those skilled in the art, a monomer is a single structural unit of a polymer or copolymer, not an oligomer or polymer. In contrast, an oligomer includes multiple chemically bonded monomers. In some embodiments, the acrylate component can include a monofunctional acrylate, a difunctional acrylate, or a mixture thereof. In some embodiments, for example, the acrylate component is methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, n-decyl (meth)acrylate, n-dodecyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2- or 3-hydroxypropyl (meth)acrylate. acrylate, 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2- or 3-ethoxypropyl (meth)acrylate, tetrahydrofurfuryl methacrylate, isobornyl (meth)acrylate, 2-(2-ethoxyethoxy)ethyl acrylate, cyclohexyl methacrylate, 2-phenoxyethyl acrylate, glycidyl acrylate, isodecyl acrylate, 2-phenoxyethyl (meth)acrylate, lauryl methacrylate, or mixtures thereof. In some embodiments, the acrylate component comprises a mono- or difunctional aliphatic urethane (meth)acrylate.

[0035] In some embodiments, the acrylate component can include one or more of allyl acrylate, allyl methacrylate, triethylene glycol di(meth)acrylate, tricyclodecane dimethanol diacrylate, and cyclohexane dimethanol diacrylate. Further, in some embodiments, the acrylate component comprises diacrylate and / or dimethacrylate esters of aliphatic, alicyclic, or aromatic diols, including 1,3- or 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, tripropylene glycol, ethoxylated or propoxylated neopentyl glycol, 1,4-dihydroxymethylcyclohexane, 2,2-bis(4-hydroxycyclohexyl)propane or bis(4-hydroxycyclohexyl)methane, hydroquinone, 4,4′-dihydroxybiphenyl, bisphenol A, bisphenol F, bisphenol S, ethoxylated or propoxylated bisphenol A, ethoxylated or propoxylated bisphenol F, or ethoxylated or propoxylated bisphenol S.

[0036] Further non-limiting examples of species suitable for inclusion in the acrylate component include: isobornyl acrylate (IBOA), available from SARTOMER under the trade name SR 506A; a difunctional acrylate available from SARTOMER under the trade name SR 833S; a trifunctional acrylate monomer available from SARTOMER under the trade name SR 533; isobornyl methacrylate available from SARTOMER under the trade name SR 423A; an alkoxylated tetrahydrofurfuryl acrylate available from SARTOMER under the trade name SR 611; a monofunctional urethane acrylate available from RAHN USA under the trade name GENOMER 1122; an aliphatic urethane diacrylate available from ALLNEX under the trade name EBECRYL 8402; a difunctional aliphatic urethane (meth)acrylate available from DYMAX under the trade name BR-952; triethylene glycol diacrylate available from SARTOMER under the trade name SR 272; and SR 1,2-dimethyl-2,4-diphenyl ether available from SARTOMER under the trade name SR 122. Triethylene glycol dimethacrylate, commercially available under the trade name 205. Other commercially available curable components may be used. Additionally, in some cases, the mono- or di-functional acrylate comprises an aliphatic polyester urethane acrylate oligomer, a urethane (meth)acrylate resin, and / or an acrylate amine oligomer resin, such as EBECRYL 7100. In some embodiments, the acrylate component comprises one or more acrylate derivatives, such as acryloylmorpholine.

[0037] In addition to the monofunctional and difunctional acrylate species components described above, it is also possible in some cases to include trifunctional or higher functionality acrylate species in the polymerizable liquid described herein. For example, in some cases, one or more tri(meth)acrylates can be used. However, it should be understood that the functionality (i.e., mono-, di-, tri-, or higher functionality) and molecular weight of the acrylate species described herein can be selected to provide a build material with a viscosity suitable for use in a desired 3D printing system. Non-limiting examples of trifunctional or higher (meth)acrylates that may be suitable for use in some embodiments described herein include: 1,1-trimethylolpropane tri(meth)acrylate, ethoxylated or propoxylated 1,1,1-trimethylolpropane tri(meth)acrylate, ethoxylated or propoxylated glycerol tri(meth)acrylate, pentaerythritol monohydroxytri(meth)acrylate, dipentaerythritol monohydroxypenta(meth)acrylate, bis(trimethylolpropane) and tetra(meth)acrylate.

[0038] The acrylate component can be present in the polymerizable liquid in any amount consistent with the purposes described herein. In some embodiments, the acrylate component is present in an amount up to about 70% by weight. For example, the acrylate component can be present in an amount of 30-70% by weight, or 40-60% by weight, based on the total weight of the polymerizable liquid.

[0039] The polymerizable liquids described herein, in some embodiments, can further include a photoinitiator component to initiate polymerization of one or more components of the liquid upon exposure to light of an appropriate wavelength. In some embodiments, the photoinitiator component can initiate polymerization of an isocyanurate that includes one or more moieties polymerizable via a free radical mechanism, such as an isocyanurate acrylate. Similarly, a photoinitiator can be used to polymerize an acrylate component. In some embodiments, a curable isocyanurate can be copolymerized with an acrylate component. In other embodiments, the curable isocyanurate and acrylate components are polymerized independently.

[0040] Any photoinitiator not inconsistent with the objectives of the present disclosure may be used. In some embodiments, the photoinitiator comprises an alpha-cleavage (unimolecular decomposition process) photoinitiator or a hydrogen abstraction photosensitizer-tertiary amine synergist operable to absorb light at about 250 nm to about 420 nm or about 300 nm to about 385 nm to generate free radicals.

[0041] Examples of alpha-cleavage photoinitiators are Irgacure 184 (CAS 947-19-3), Irgacure 369 (CAS 119313-12-1), and Irgacure 819 (CAS 162881-26-7). An example of a photosensitizer-amine combination is Darocur BP (CAS 119-61-9) with diethylaminoethyl methacrylate.

[0042] Further, in some examples, suitable photoinitiators include: benzoins, including benzoin ethers, such as benzoin methyl ether, benzoin ethyl ether, and benzoin isopropyl ether, benzoin phenyl ether, and benzoin acetate; acetophenones, including 2,2-dimethoxyacetophenone and 1,1-dichloroacetophenone; benzil ketals, such as benzil, benzil dimethyl ketal, and benzil diethyl ketal; anthraquinones, including 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, and 2-amylanthraquinone; triphenyl anthraquinones, including benzoin ethers, such as benzoin methyl ether, benzoin ethyl ether, and benzoin isopropyl ether, benzoin phenyl ether, and benzoin acetate; Phenylphosphine, benzoylphosphine oxides, such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide (Lucirin TPO), benzophenone and benzophenones, such as 4,4'-bis(N,N'-dimethylamino)benzophenone, thioxanthones and xanthones, acridine derivatives, phenazine derivatives, quinoxaline derivatives or 1-phenyl-1,2-propanedione, 2-O-benzoyloxime, 1-aminophenyl ketones or 1-hydroxyphenyl ketones, such as 1-hydroxycyclohexyl phenyl ketone, phenyl 1-hydroxyisopropyl ketone and 4-isopropylphenyl 1-hydroxyisopropyl ketone.

[0043] Suitable photoinitiators may also include those operable for use with a HeCd laser radiation source, including acetophenones, 2,2-dialkoxybenzophenones, and 1-hydroxyphenyl ketones, such as 1-hydroxycyclohexyl phenyl ketone or 2-hydroxyisopropyl phenyl ketone (=2-hydroxy-2,2-dimethylacetophenone). Additionally, in some cases, suitable photoinitiators include those operable for use with an Ar laser radiation source, including benzil ketals, such as benzil dimethyl ketal. In some embodiments, the photoinitiator includes an α-hydroxyphenyl ketone, benzil dimethyl ketal, or 2,4,6-trimethylbenzoyldiphenylphosphine oxide, or mixtures thereof.

[0044] Another class of suitable photoinitiators includes ionic dye-counterion compounds, which in some instances can absorb actinic radiation and generate free radicals for polymerization initiation. In some embodiments, polymerizable liquids containing ionic dye-counterion compounds can polymerize upon exposure to visible light within a tunable wavelength range of about 400 nm to about 700 nm. Ionic dye-counterion compounds and their modes of operation are disclosed in EP 0223587 and U.S. Pat. Nos. 4,751,102; 4,772,530; and 4,772,541.

[0045] The photoinitiator can be present in the polymerizable liquid described herein in any amount not inconsistent with the objectives of the present disclosure. In some embodiments, the photoinitiator is present in an amount up to about 5% by weight, based on the total weight of the polymerizable liquid. In some cases, the photoinitiator is present in an amount ranging from about 0.1% to about 5% by weight.

[0046] Additionally, in some embodiments, the polymerizable liquids described herein may further include one or more sensitizers. Sensitizers may be added to increase the effectiveness of one or more photoinitiators that may also be present. Any sensitizer not inconsistent with the objectives of the present disclosure may be used. In some cases, the sensitizer includes isopropylthioxanthone (ITX) or 2-chlorothioxanthone (CTX).

[0047] The sensitizer can be present in the polymerizable liquid in any amount not inconsistent with the objectives of the present disclosure, hi some embodiments, the sensitizer is present in an amount ranging from about 0.1% to about 2% by weight, or from about 0.5% to about 1% by weight, based on the total weight of the polymerizable liquid.

[0048] In some embodiments, one or more UV absorbers and / or light stabilizers may be present in the polymerizable liquid. In some embodiments, for example, the one or more UV absorbers and / or light stabilizers may be present in an amount of 0.1 to 2% by weight, based on the total weight of the polymerizable liquid. In some embodiments, the UV absorbers and / or light stabilizers are commercially available under the trade designation TINUVIN® from BASF, Florham Park, New Jersey.

[0049] In another aspect, a method for printing a 3D article or object is described herein.The method for printing a 3D article or object can include forming a 3D article layer by layer from multiple layers of the polymerizable liquid described herein.Any of the polymerizable liquids or components described herein can be used to create an article by additive manufacturing.

[0050] In some embodiments, the method includes providing a polymerizable liquid including a curable isocyanurate component in an amount of at least 20% by weight, based on the total weight of the polymerizable liquid, and an organophosphate component including one or more organophosphate compounds. The polymerizable liquid is printed and cured to form an article. In some embodiments, the polymerizable liquid also includes an acrylate component. The acrylate component can include an acrylate monomer, an acrylate oligomer, or a mixture thereof.

[0051] As further described herein, the polymerizable liquid may further include a photoinitiator component, and curing of the polymerizable liquid may occur by irradiation of the liquid with light of an appropriate wavelength to initiate free radical polymerization.

[0052] In some embodiments, a layer of polymerizable liquid can be deposited according to an image of a 3D article in a computer-readable format during the formation of the three-dimensional article. The polymerizable liquid can be deposited according to preselected computer-aided design (CAD) parameters. Further, in some cases, one or more layers of polymerizable liquid described herein have a thickness of about 10 μm to about 100 μm, about 10 μm to about 80 μm, about 10 μm to about 50 μm, about 20 μm to about 100 μm, about 20 μm to about 80 μm, or about 20 μm to about 40 μm. Other thicknesses are possible.

[0053] It should further be understood that the methods of printing 3D articles described herein may include so-called "multi-jet" or "stereolithography" 3D printing methods. For example, in some examples, the multi-jet method of printing 3D articles includes selectively depositing layers of the polymerizable liquid described herein onto a substrate, such as a build pad of a 3D printing system. Furthermore, in some embodiments, the methods described herein further include supporting at least one of the layers of the polymerizable liquid with a support material. Any support material not inconsistent with the objectives of the present disclosure may be used.

[0054] It is also possible to use stereolithography to form 3D articles from the polymerizable liquids described herein. For example, in some cases, a method for printing a 3D article includes holding a polymerizable liquid in a container and selectively applying energy to the polymerizable liquid in the container to solidify at least a portion of the polymerizable liquid, thereby forming a solidified layer that defines a cross section of the 3D article. In addition, the method described herein further includes raising or lowering the solidified layer to provide a new or second layer of polymerizable liquid, and then selectively applying energy again to the polymerizable liquid in the container to solidify at least a portion of the new or second polymerizable liquid that defines a second cross section of the 3D article. Furthermore, the first and second cross sections of the 3D article can be bonded or adhered to each other in the z direction (or a build direction corresponding to the above-mentioned rising or lowering direction) by applying energy to solidify the polymerizable liquid. Additionally, selectively applying energy to the polymerizable liquid in the container can include applying electromagnetic radiation, e.g., UV and / or visible radiation, having sufficient energy to initiate polymerization of the polymerizable material described herein. Additionally, in some cases, raising or lowering the solidified layer of polymerizable liquid is performed using an elevator platform disposed within the container of fluid modeling material. The methods described herein can also include planarizing the new layer of polymerizable liquid provided by raising or lowering the elevator platform. Such planarization can, in some cases, be performed by a wiper or roller.

[0055] Articles printed according to the methods described herein can exhibit one or more desirable mechanical properties. 3D articles printed from the polymerizable liquids described herein can, in some embodiments, exhibit a tensile modulus of 2700-3200 MPa. 3D printed articles can, in some embodiments, exhibit a tensile strength of at least 55-65 MPa. The tensile strength and tensile modulus values ​​provided herein can be determined according to ASTM D638.

[0056] Articles printed according to the methods described herein can also exhibit desirable flame retardant and / or flame resistant properties. The articles can exhibit, for example, a Limiting Oxygen Index (LOI) of 25-30% or 28-30% according to ISO 4589. Additionally, articles printed according to the methods described herein can comply with the provisions of 14 CFR §23.2325.

[0057] These foregoing embodiments are further illustrated in the following non-limiting examples. EXAMPLES

[0058] Table 1 provides formulations of polymerizable liquids according to some embodiments described herein. [Table 1]

[0059] Three rectangular strips, each 3 mm thick, were printed from the polymerizable liquid of Formula 1. The strips had sufficient length and width for vertical burn testing in accordance with 14 CFR §23.2325. The burn length is the distance from the original edge to any evidence of damage to the specimen due to thermal shock, including areas of partial or complete consumption, charring, or embrittlement, but not including areas that are sooted, stained, bent, or discolored, or where the material has shrunk or melted from the heat source. The pass or pass criteria are as follows: Afterflame: Maximum average 15.0 seconds Drip burn: Maximum average 5.0 seconds Burn Length: Maximum average 8.0 inches

[0060] The results of the vertical burn test of the three sample strips are shown in Table 2: [Table 2]

[0061] As shown in Table 2, the printed samples passed the vertical burn flame test, demonstrating substantial flame retardancy.

[0062] Further non-limiting exemplary embodiments are described below.

[0063] Embodiment 1. A polymerizable liquid comprising: a curable isocyanurate component in an amount of at least 20% by weight, based on the total weight of the polymerizable liquid; and An organophosphate component comprising one or more organophosphate compounds.

[0064] Embodiment 2. The polymerizable liquid of embodiment 1, wherein the curable isocyanurate component is polymerizable via free radical polymerization.

[0065] Embodiment 3. The polymerizable liquid of embodiment 1 or embodiment 2, wherein the curable isocyanurate component comprises an isocyanurate polyacrylate, a polyallyl isocyanurate, or a mixture thereof.

[0066] Embodiment 4. The polymerizable liquid of any of the previous embodiments, wherein the isocyanurate polyacrylate is of Formula I: [ka] In the formula, R 1 ~R 3 is independently selected from the group consisting of hydrogen and alkyl, and m, n, and p are independently integers ranging from 1 to 10.

[0067] Embodiment 5. The polymerizable liquid of any of the previous embodiments, wherein the polyallyl isocyanurate is of Formula II: [ka] In the formula, m, n, and p are independently integers ranging from 1 to 10.

[0068] Embodiment 6. The polymerizable liquid of any of the preceding embodiments, wherein the organophosphate component is present in an amount of 10 to 40 weight percent, based on the total weight of the polymerizable liquid.

[0069] Embodiment 7. The polymerizable liquid of any of the preceding embodiments, wherein the one or more organophosphate compounds is of formula III: [ka] In the formula, R 1 ~R 3 is independently selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, heteroalkyl, heteroalkenyl, heterocyclyl, aryl, and heteroaryl.

[0070] Embodiment 8. The polymerizable liquid of any of the previous embodiments, wherein the one or more organophosphate compounds comprises a bis(organophosphate).

[0071] Embodiment 9. The polymerizable liquid of any of the preceding embodiments, wherein the curable isocyanurate component is present in an amount of 30 to 80 weight percent, based on the total weight of the polymerizable liquid.

[0072] Embodiment 10. The polymerizable liquid of any of the previous embodiments, further comprising an acrylate component.

[0073] Embodiment 11. The polymerizable liquid of embodiment 10, wherein the acrylate component is present in an amount of 30 to 70 weight percent, based on the total weight of the polymerizable liquid.

[0074] Embodiment 12. The polymerizable liquid of embodiment 10 or embodiment 11, wherein the acrylate component comprises a mixture of acrylate monomers and acrylate oligomers.

[0075] Embodiment 13. The polymerizable liquid of any of the previous embodiments, further comprising a photoinitiator component.

[0076] Embodiment 14. The polymerizable liquid of embodiment 13, wherein the photoinitiator component is present in an amount of 0.1 to 5 weight percent, based on the total weight of the polymerizable liquid.

[0077]

[0046] Embodiment 15. A method for printing a three-dimensional object, comprising: The polymerizable liquid of any of embodiments 1 to 14, for example, a curable isocyanurate component in an amount of at least 20% by weight, based on the total weight of the polymerizable liquid; and an organophosphate component comprising one or more organophosphate compounds; providing a polymerizable liquid comprising: A process in which a polymerizable liquid is printed and cured using light to form an article. A method comprising:

[0078] Embodiment 16. The method of embodiment 15, wherein the article has a limiting oxygen index according to ISO 4589 of 25 to 30%.

[0079] Embodiment 17. The method of embodiment 15 or embodiment 16, wherein the article has a limiting oxygen index according to ISO 4589 of 28 to 30%.

[0080] Embodiment 18. The method of any of embodiments 15-17, wherein the polymerizable liquid is provided in a layer-by-layer process.

[0081] Embodiment 19. The method of any of embodiments 15-18, wherein the polymerizable liquid further comprises a photoinitiator component, and curing of the polymerizable liquid proceeds via free radical polymerization.

[0082] Embodiment 20. The method of any of embodiments 15-19, wherein the curable isocyanurate component comprises an isocyanurate polyacrylate, a polyallyl isocyanurate, or a mixture thereof.

[0083] Embodiment 21. The method of embodiment 20, wherein the isocyanurate polyacrylate is of formula I: [ka] In the formula, R 1 ~R 3 is independently selected from the group consisting of hydrogen and alkyl, and m, n, and p are independently integers ranging from 1 to 10.

[0084] Embodiment 22. The method of embodiment 20, wherein the polyallyl isocyanurate is of formula II: [ka] In the formula, m, n, and p are independently integers ranging from 1 to 10.

[0085] Embodiment 23. The method of any of embodiments 15-22, wherein the organophosphate component is present in an amount of 10 to 40 weight percent, based on the total weight of the polymerizable liquid.

[0086] Embodiment 24. The method of any of embodiments 15-23, wherein the one or more organophosphate compounds is of the formula: [ka] In the formula, R 1 ~R 3 is independently selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, heteroalkyl, heteroalkenyl, heterocyclyl, aryl, and heteroaryl.

[0087] Embodiment 25. The method of any of embodiments 15-24, wherein the one or more organophosphate compounds comprises a bis(organophosphate).

[0088] Embodiment 26. The method of any of embodiments 15-25, wherein the curable isocyanurate is present in an amount from 30 to 80 weight percent, based on the total weight of the polymerizable liquid.

[0089] Embodiment 27. The method of any of embodiments 15-26, wherein the polymerizable liquid further comprises an acrylate component.

[0090] Embodiment 28. The method of embodiment 27, wherein the acrylate component is present in an amount of 30 to 70 weight percent, based on the total weight of the polymerizable liquid.

[0091] Embodiment 29. The method of embodiment 27 or embodiment 28, wherein the acrylate component comprises a mixture of acrylate monomers and acrylate oligomers.

[0092] All patents mentioned herein are incorporated by reference in their entirety. In accomplishing the various objectives of the present invention, various embodiments of the present invention have been described. It is to be recognized that these embodiments are merely illustrative of the principles of the present invention. Many modifications and adaptations thereof will be readily apparent to those skilled in the art without departing from the spirit and scope of the present invention.

Claims

1. A polymerizable liquid comprising: a curable isocyanurate component in an amount of at least 20% by weight, based on the total weight of the polymerizable liquid; and An organophosphate component comprising one or more organophosphate compounds. Including, The curable isocyanurate component comprises a mixture of isocyanurate polyacrylate and polyallyl isocyanurate. Polymerizable liquid.

2. The polymerizable liquid of claim 1 , wherein the curable isocyanurate component is polymerizable via free radical polymerization.

3. The isocyanurate polyacrylate has Formula I: 【Chemistry 1】 The In the formula, R １ ~R ３ are each independently selected from the group consisting of hydrogen and alkyl, and m, n, and p are each independently an integer ranging from 1 to 10. The polymerizable liquid according to claim 1 .

4. The polyallyl isocyanurate has the formula II: 【Chemistry 2】 The In the formula, m, n, and p are independently integers ranging from 1 to 10. The polymerizable liquid according to claim 1 .

5. 10. The polymerizable liquid of claim 1, wherein the organophosphate component is present in an amount of 10 to 40 weight percent, based on the total weight of the polymerizable liquid.

6. The one or more organophosphate compounds have the following formula: 【Chemistry 3】 The In the formula, R １ ~R ３ is independently selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, heteroalkyl, heteroalkenyl, heterocyclyl, aryl, and heteroaryl. The polymerizable liquid according to claim 1 .

7. 10. The polymerizable liquid of claim 1, wherein the curable isocyanurate component is present in an amount of 30 to 80 weight percent, based on the total weight of the polymerizable liquid.

8. The polymerizable liquid of claim 1, further comprising an acrylate component in addition to the curable isocyanurate component and the organophosphate component.

9. The polymerizable liquid of claim 8 , wherein the acrylate component comprises a mixture of acrylate monomers and acrylate oligomers.

10. The polymerizable liquid of claim 1 further comprising a photoinitiator component.

11. 11. The polymerizable liquid of claim 10, wherein the photoinitiator component is present in an amount of 0.1 to 5 weight percent, based on the total weight of the polymerizable liquid.

12. 1. A method for printing a three-dimensional object, comprising: Providing a polymerizable liquid; and Printing and curing the polymerizable liquid with light to form the article. Including, The polymerizable liquid is a curable isocyanurate component in an amount of at least 20% by weight, based on the total weight of the polymerizable liquid; and An organophosphate component comprising one or more organophosphate compounds. Including, The curable isocyanurate component comprises a mixture of isocyanurate polyacrylate and polyallyl isocyanurate. method.

13. 13. The method of claim 12, wherein the article has a limiting oxygen index according to ISO 4589 of 25 to 30%.

14. 13. The method of claim 12, wherein the polymerizable liquid is applied in a layer-by-layer process.

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