Build materials for 3D printing

Abstract

To provide polymerizable liquids which, in some embodiments, can produce 3D printed articles of high resolution and desirable mechanical properties.SOLUTION: In one aspect, a polymerizable liquid comprises an acrylate component, a polymeric additive, and a monomeric curing agent, where the acrylate component and monomeric curing agent are copolymerizable upon exposure to light. If being copolymerizable, the acrylate component and monomeric curing agent can form a copolymer. As described further herein, the monomeric curing agent can cause further reaction of the copolymer with one or more crosslinking species to link the copolymer with one more polymeric networks.SELECTED DRAWING: None

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority pursuant to Patent Cooperation Treaty Article 8 to U.S. Provisional Patent Application No. 62 / 873,486, filed July 12, 2019, which is incorporated herein by reference in its entirety. [Technical Field]

[0002] The present invention relates to three-dimensional build materials, and more particularly to polymerizable liquids for use in three-dimensional printing systems. [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 instances, the build material is solid at ambient temperature and is converted to a liquid at elevated jetting temperatures. In other instances, the build material is liquid at ambient temperature.

[0004] The build material can include a variety of chemical species. The selection of chemical species to include 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 are generally capable of printing parts with high resolution in DLP systems. However, in many cases, the resulting parts lack the desired mechanical properties and can be prone to fracture or other degradation pathways. Summary of the Invention [Means for solving the problem]

[0005] In view of the above, in some embodiments, described herein is a polymerizable liquid capable of producing 3D-printed articles with high resolution and desirable mechanical properties. In one aspect, the polymerizable liquid includes an acrylate component, a polymer additive, and a monomeric curing agent, where the acrylate component and the monomeric curing agent are copolymerizable upon exposure to light. When copolymerizable, the acrylate component and the monomeric curing agent can form a copolymer. As further described herein, the monomeric curing agent can further react with one or more crosslinking species to chemically link the copolymer to one or more polymer networks. In some embodiments, the monomeric curing agent enables linkage between the copolymer and the polymeric additive. The chemical linkage of the polymer networks can provide 3D-printed articles with enhanced mechanical properties. In some embodiments, the polymeric additive includes one or more thermoplastics, such as a multiblock copolymer. In some cases, the multiblock copolymer includes a polyurethane.

[0006] In another aspect, methods of printing three-dimensional articles are described herein. In some embodiments, the methods of printing three-dimensional articles include providing a polymerizable liquid comprising an acrylate component, a polymer additive, and a monomer curing agent. The polymerizable liquid is irradiated with light to form an article, the article comprising a polymer composite material comprising the polymer additive and a copolymer comprising the acrylate component and the monomer curing agent. In some embodiments, the article is formed by a layer-by-layer process, where the formation of layers is achieved by depositing and irradiating layers of the polymerizable liquid.

[0007] Additionally, the polymerizable liquid may further include a cross-linking component, and the monomeric curing agent of the copolymer may initiate a cross-linking reaction with the cross-linking component. The monomeric curing agent, in some embodiments, may initiate a cross-linking reaction to link the copolymer with one or more polymeric species in the polymerizable liquid. For example, the monomeric curing agent may initiate a reaction to cross-link the copolymer with a polymeric additive. In some embodiments, the cross-linking reaction is initiated following the formation of the article. The article may be heated or irradiated, for example, to initiate cross-linking or curing via the monomeric curing agent. The cross-linking or curing, in some embodiments, may induce a color change in the article. Notably, such a color change may occur in the absence of any pigment added to the polymerizable liquid.

[0008] In some embodiments, no polymer additive is present in the polymerizable liquid. In such embodiments, the polymerizable liquid includes an acrylate component, a monomer curing agent, and a cross-linking component. Irradiation of the polymer liquid can form a copolymer between the acrylate component and the monomer curing agent. As described herein, the monomer curing agent of the copolymer can then initiate a reaction with the cross-linking component via thermal and / or light stimulation.

[0009] In another aspect, the polymerizable liquid includes an acrylate component, a polymer additive, and a monomer solvent for the polymer additive, where the monomer solvent and the acrylate component are copolymerizable upon exposure to light. The monomer solvent can partially or completely solubilize the polymer additive in the polymerizable liquid. Thus, the monomer solvent allows for the incorporation of polymeric materials into the polymerizable liquid that would otherwise phase separate in a mixture containing the acrylate component. In some embodiments, for example, the polymer additive includes one or more thermoplastics. In some embodiments, the thermoplastics can include a multiblock copolymer.

[0010] In a further aspect, a method for printing a three-dimensional article includes providing a polymerizable liquid comprising an acrylate component, a polymer additive, and a monomer solvent for the polymer additive. The polymerizable liquid is irradiated with light to form an article, the article comprising a polymer composite comprising the polymer additive and a copolymer comprising the acrylate component and the monomer solvent. In some embodiments, the article is formed by a layer-by-layer process, where the formation of layers is achieved by depositing and irradiating layers of the polymerizable liquid.

[0011] These and other embodiments are further described in the detailed description that follows. DETAILED DESCRIPTION OF THE INVENTION

[0012] The embodiments described herein can be more readily understood by reference 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.

[0013] Additionally, 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" is considered to include any and all subranges beginning with a minimum value of 1.0 or greater and ending with a maximum value of 10.0 or less, such as 1.0 to 5.3, or 4.7 to 10.0, or 3.6 to 7.9.

[0014] All ranges disclosed herein should also be considered to include the endpoints of the range, unless otherwise stated. For example, a range "between 5 and 10" should generally be considered to include the endpoints 5 and 10.

[0015] Furthermore, when the phrase "up to" is used in reference to an amount or quantity, it is understood that the amount is at least a detectable amount or quantity. For example, a substance present in an amount that is up to a particular amount can be present in an amount from a detectable amount up to and including the particular amount.

[0016] The terms "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 currently known in the art or that may become known in the future that use build materials or inks to produce three-dimensional objects.

[0017] In one aspect, a polymerizable liquid for use in 3D printing applications is described herein. The polymerizable liquid can be used, for example, in some embodiments, in DLP, SLA, and MJP printing applications. The polymerizable liquid includes an acrylate component, a polymer additive, and a monomer curing agent, and the acrylate component and the monomer curing agent are copolymerizable upon exposure to light. When copolymerizable, the acrylate component and the monomer curing agent can form a copolymer.

[0018] The acrylate component can comprise one or a mixture of photopolymerizable acrylate species. In some embodiments, for example, the acrylate component can comprise 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 comprises multiple chemically linked monomers. In some embodiments, the acrylate component can comprise 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 β-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 monofunctional or difunctional aliphatic urethane (meth)acrylate.

[0019] The acrylate component, in some embodiments, 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.

[0020] Further non-limiting examples of species suitable for inclusion in the acrylate component include: isobornyl acrylate (IBOA), available commercially from SARTOMER under the trade name SR 506A; isobornyl methacrylate, available commercially from SARTOMER under the trade name SR 423A; alkoxylated tetrahydrofurfuryl acrylate, available commercially from SARTOMER under the trade name SR 611; monofunctional urethane acrylate, available commercially from RAHN USA under the trade name GENOMER 1122; aliphatic urethane diacrylate, available commercially from ALLNEX under the trade name EBECRYL 8402; difunctional aliphatic urethane (meth)acrylate, available commercially from DYMAX under the trade name BR-952; triethylene glycol diacrylate, available commercially from SARTOMER under the trade name SR 272; and triethylene glycol dimethacrylate, available commercially from SARTOMER under the trade name SR 205. Other commercially available curable components may also 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.

[0021] 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 of up to about 90 wt%, up to about 85 wt%, up to about 80 wt%, or up to about 75 wt%, based on the total weight of the ink; up to about 90 wt%, up to about 85 wt%, up to about 80 wt%, or up to about 75 wt%, based on the total weight of the polymerizable liquid. For example, the acrylate component can be present in an amount of 20-90 wt%. In some embodiments, the polymerizable liquid comprises about 20-70 wt%, 40-90 wt%, 55-90 wt%, 60-90 wt%, 65-90 wt%, 65-85 wt%, 70-90 wt%, 75-90 wt%, or 80-90 wt% of the acrylate component, based on the total weight of the ink. Additionally, in some embodiments, the polymerizable liquid comprises 30 to 45% or 50 to 70% by weight of the acrylate component, based on the total weight of the ink.

[0022] In addition to the monofunctional and difunctional acrylate species components described above, in some cases, it is also possible to include trifunctional or higher functionality acrylate species in the polymerizable liquids 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, and bis(trimethylolpropane)tetra(meth)acrylate.

[0023] As described herein, the polymerizable liquid also includes a polymer additive. The inclusion of the polymer additive along with the acrylate component can improve one or more mechanical properties of an article formed from the polymerizable liquid via additive manufacturing techniques. In some embodiments, the inclusion of the polymer additive can increase one or more of the tensile strength, shear strength, flexibility, elongation, heat deflection temperature, and / or impact resistance of the article.

[0024] In some cases, the polymer additives described herein include one or more thermoplastics or thermoplastic components. The thermoplastics described herein can include multiblock copolymers. In some embodiments, for example, the polymer additive includes a thermoplastic polyurethane (TPU). The thermoplastic polyurethane can be a polyester TPU, a polyether TPU, a polycaprolactone TPU, or a mixture thereof. In some cases, the thermoplastic polyurethane is aromatic (based on isocyanates such as MDI) or aliphatic (based on isocyanates such as H12 MDI, HDI, and IPDI). TPUs can have hard and soft sequences or domains, with the hard segments formed from short-chain diols ("chain extenders") and the soft segments formed from long-chain diols. The hard-to-soft ratio, as well as the structure and / or molecular weight of the diols, can be varied to produce TPU variants with a wide range of physical properties.

[0025] The polymeric additive can be present in the polymerizable liquid in any amount consistent with the purposes described herein. The amount of polymeric additive in the polymerizable liquid can be selected according to several considerations, including, but not limited to, the chemical identity of the acrylate component, the chemical identity of the polymeric additive, and / or the desired mechanical properties of the resulting article formed from the polymerizable liquid via additive manufacturing. In some embodiments, the polymer additive is present in the build material in an amount of 5-50%, 10-40%, 15-35%, 20-30%, 5-25%, 5-20%, 5-15%, 5-10%, 10%-25%, 30%-40%, 14%-20%, 5%, 7%, 9%, 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, or 30% by weight.

[0026] In addition to the acrylate component and the polymer additive, the polymerizable liquid also contains a monomeric curing agent. The acrylate component and the monomeric curing agent are copolymerizable upon exposure to light. When copolymerizable, the acrylate component and the monomeric curing agent form a copolymer. In particular, the monomeric curing agent allows the copolymer to further react with one or more crosslinking species, linking the copolymer into one or more polymer networks. In some embodiments, the monomeric curing agent allows the copolymer to link with the polymeric additive. Chemical linking of the polymer networks can provide 3D-printed articles with enhanced mechanical properties. Furthermore, chemical linking between polymer networks presents a fundamentally different structure compared to physically interpenetrating polymer networks.

[0027] Following copolymer formation with the acrylate component, the monomeric curing agent can further react with one or more crosslinking species. In some embodiments, heat or light is applied to stimulate the reaction between the monomeric curing agent and the crosslinking species. In some embodiments, the monomeric curing agent can act as an initiator or catalyst for the crosslinking reaction. The monomeric curing agent can include any species that can copolymerize with the acrylate component while maintaining functionality to participate in the crosslinking reaction following copolymer formation. In some embodiments, the monomeric curing agent acts as an initiator or catalyst for the crosslinking reaction. In some embodiments, for example, the monomeric curing agent includes one or more imidazoles, which can be used to copolymerize with the acrylate component. In one embodiment, for example, the monomeric curing agent includes vinyl-imidazole. In some embodiments, epoxy and / or isocyanate crosslinking species can react with the imidazole to form crosslinks between the imidazole-acrylate copolymer and polymer additives or other species in the polymerizable liquid. In some cases, the unsaturated nitrogen in the imidazole ring can act as an anionic initiator, forming a 1:1 epoxy-imidazole adduct, which can then be further polymerized by reacting with another epoxy resin crosslinking component.

[0028] In some embodiments, the entire article or portion thereof is formed prior to initiation of the reaction between the monomeric curing agent and the cross-linking component. For example, the article can be printed via copolymerization of the acrylate component and the monomeric curing agent. Subsequent formation can involve heating or irradiating the article to initiate the reaction between the monomeric curing agent and the cross-linking component.

[0029] Additionally, in some embodiments, the monomeric curing agent can partially or completely solubilize the polymeric additive. Thus, the monomeric curing agent allows for the incorporation of polymeric materials into the polymerizable liquid that would otherwise phase separate in a mixture containing an acrylate component. In some embodiments, for example, the monomeric curing agent can be a solvent for one or more of the TPU species described above.

[0030] The monomeric curing agent can be present in the polymerizable liquid in any desired amount. The amount of monomeric curing agent can be selected according to several considerations, including, but not limited to, the chemical identity of the acrylate component and the desired amount of crosslinking between the copolymer incorporating the monomeric curing agent and one or more polymer species in the polymerizable liquid. Generally, the monomeric curing agent can be present in the polymerizable liquid in an amount of 2 to 20 weight percent.

[0031] The crosslinking component for reaction with the monomer curing agent can include an epoxy resin, an isocyanate component, a polyol component, or a mixture thereof. Any epoxy resin consistent with the objectives of the present disclosure can be used, such as epoxidized bisphenol A, epoxidized bisphenol F, epoxidized phenol novolac epoxy, epoxidized cresol novolac epoxy, brominated multifunctional epoxy, multifunctional epoxy resin (TGMDA or TGPAP), cycloaliphatic epoxy, epoxidized polypropylene glycol carrier (weight average molecular weight 400, 1000, or 2000), epoxidized phenoxyethyl acrylate carrier, or any combination thereof. Any isocyanate component consistent with the objectives of the present disclosure can be used. Exemplary isocyanate components include aliphatic diisocyanates, such as hexamethylene diisocyanate (HDI), methylene dicyclohexyl diisocyanate (HMDI) or hydrogenated MDI, and isophorone diisocyanate (IPDI). Any polyol component consistent with the objectives of the present disclosure can also be used.

[0032] In some embodiments, a crosslinking component can be coated onto the particles to form a core-shell configuration. The particles coated with the crosslinking component can have any desired chemical identity. The chemical identity of the particles can be selected according to several considerations, including, but not limited to, the identity of the acrylate component and the desired mechanical properties of the resulting article formed from the polymerizable liquid via additive manufacturing. In some embodiments, the particles comprise a thermoplastic or thermoset material. Alternatively, the particles can comprise an elastomer. In some embodiments, for example, the coated particles are commercially available from Kaneka Texas Corporation under the trade name Kane Ace® MX. The particle coating can be crosslinked with an acrylate copolymer containing a monomeric curing agent. The monomeric curing agent can, for example, react with the crosslinking component of the particle to chemically link the coated particle to the acrylate copolymer incorporating the monomeric curing agent.

[0033] The cross-linking component can be present in the polymerizable liquid in any desired amount. The amount of cross-linking component can be selected according to several considerations, including, but not limited to, the identity of the copolymer comprising the acrylate component and the monomer curing agent, the identity of the cross-linking component, and / or the amount of cross-linking desired. Generally, the cross-linking component can be present in the polymerizable liquid in an amount of 15 to 50 weight percent.

[0034] In some embodiments, the polymerizable liquid does not include a polymer component. The polymerizable liquid can include, for example, an acrylate component, a cross-linking component, and a monomeric curing agent, where the acrylate component and the monomeric curing agent are copolymerizable upon exposure to light. In such embodiments, the acrylate component and the monomeric curing agent form a copolymer. As described herein, the monomeric curing agent of the copolymer can subsequently react with a species of the cross-linking component. In this manner, the copolymer including the monomeric curing agent and the acrylate component is chemically linked to one or more polymer networks formed by the cross-linking component. In some embodiments, the monomeric curing agent is activated by heat or light to react with the cross-linking component. The monomeric curing agent can be, for example, a catalyst or initiator for reaction with the cross-linking component and cross-linking.

[0035] The polymerizable liquid also includes a photoinitiator component for initiating copolymerization of the acrylate component and the monomer curing agent upon exposure to light. Any photoinitiator not inconsistent with the objectives of the present disclosure may be used. In some embodiments, the photoinitiator preferably includes an alpha-cleavage (unimolecular decomposition process) photoinitiator or a hydrogen abstraction photosensitizer-tertiary amine synergist capable of absorbing light at about 250 nm to about 420 nm or about 300 nm to about 385 nm to generate free radicals.

[0036] 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.

[0037] 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; benzil ketals, such as dimethyl ketal and benzil diethyl ketal; anthraquinones, including 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, and 2-amylanthraquinone; triphenylphosphine; benzoylphosphine oxides, such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide (Lucirin TPO); benzophenone and benzophenones such as 4,4'-bis(N,N'-dimethylamino)benzophenone; thioxanthone and xanthone; 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.

[0038] Suitable photoinitiators also include those that can be used with HeCd laser radiation sources, including acetophenone, 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 that can be used with Ar laser radiation sources, including benzil ketals such as benzil dimethyl ketal. In some embodiments, the photoinitiator includes α-hydroxyphenyl ketone, benzil dimethyl ketal, or 2,4,6-trimethylbenzoyldiphenylphosphine oxide, or mixtures thereof.

[0039] Another class of suitable photoinitiators includes ionic dye-counterion compounds, which can optionally 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 mode of operation are disclosed in EP 0223587 and U.S. Pat. Nos. 4,751,102; 4,772,530; and 4,772,541.

[0040] The photoinitiator can be present in the polymerizable liquids described herein in any amount consistent with the objectives of the present disclosure. In some embodiments, the photoinitiator is present in an amount of up to about 5 wt. %, based on the total weight of the polymerizable liquid. In some cases, the photoinitiator is present in an amount ranging from about 0.1 wt. % to about 5 wt. %.

[0041] Additionally, in some embodiments, the polymerizable liquids described herein can further include one or more sensitizers. The sensitizers can 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 can be used. In some cases, the sensitizer includes isopropylthioxanthone (ITX) or 2-chlorothioxanthone (CTX).

[0042] The sensitizer can be present in the polymerizable liquid in any amount consistent 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.

[0043] 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 wt. %, based on the total weight of the polymerizable liquid. In some embodiments, the UV absorbers and / or light stabilizers are commercially available from BASF, Florham Park, New Jersey, under the trade designation TINUVIN®.

[0044] 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 polymerizable material described herein can be used to manufacture an article by additive manufacturing.

[0045] In some embodiments, a method for printing a three-dimensional article includes providing a polymerizable liquid including an acrylate component, a polymer additive, and a monomer curing agent. The polymerizable liquid is irradiated with light to form an article, the article including a polymer composite including the polymer additive and a copolymer including the acrylate component and the monomer curing agent. In some embodiments, the article is formed by a layer-by-layer process, where the layer formation occurs by depositing and irradiating layers of the polymerizable liquid. The acrylate component, the polymer additive, and the monomer curing agent can have any composition and / or properties described herein. In some embodiments, for example, the polymer additive includes one or more TPU species, and the monomer curing agent includes one or more polymerizable imidazole species.

[0046] As described herein, the polymerizable liquid may further include a cross-linking component. The cross-linking component can have any composition and / or properties described herein. In some embodiments, for example, the cross-linking component includes an epoxy resin, an isocyanate component, a polyol component, or a mixture thereof. Additionally, the cross-linking component can be coated onto particles as described herein. In embodiments in which the cross-linking component is present in the polymerizable liquid, the method of printing a 3D article can further include cross-linking the cross-linking component with a copolymer including an acrylate component and a monomeric curing agent. In some embodiments, the cross-linking is initiated by reaction of the monomeric curing agent with the cross-linking component. The monomeric curing agent can be, for example, a catalyst or initiator for the cross-linking reaction. After formation of the copolymer including the monomeric curing agent and the acrylate component, heat or light can be applied to initiate cross-linking between the copolymer and the cross-linking component. In some embodiments, the cross-linking component chemically bonds the copolymer into one or more polymer networks. For example, the cross-linking component can chemically bond the copolymer including the acrylate component and the monomeric curing agent to a polymer additive in the polymerizable liquid. In certain embodiments, the cross-linking component can chemically bond the copolymer to one or more TPU species of the polymerizable liquid. Alternatively, the cross-linking component can chemically bond the copolymer including the acrylate component and the monomer curing agent to a particle coated with the cross-linking component.

[0047] In some embodiments, three-dimensional articles printed from polymerizable liquids are black after the cross-linking reaction between the monomer curing agent and the cross-linking component. In such embodiments, the polymerizable liquid is free or substantially free of any pigment species. Thus, the desired black color can be achieved using the materials and systems described herein without the need to add pigments to the polymerizable liquid. The black color of the three-dimensional article, in some embodiments, can be homogeneous or substantially homogeneous throughout the article.

[0048] In another aspect, the polymerizable liquid comprises an acrylate component, a polymer additive, and a monomer solvent for the polymer additive, wherein the monomer solvent and the acrylate component are copolymerizable upon exposure to light. In some embodiments, the acrylate component and the polymer additive can comprise any of the compositions and / or properties described hereinabove.

[0049] The monomer solvent can partially or completely solubilize the polymer additive in the polymerizable liquid. Thus, the monomer solvent allows for the incorporation of polymeric materials into the polymerizable liquid that would otherwise phase separate in a mixture containing an acrylate component. In some embodiments, for example, the polymer additive comprises one or more thermoplastics, including any of the TPU species described herein. In some embodiments, the monomer solvent can partially or completely solubilize one or more TPU species in the polymerizable liquid. In some embodiments, the monomer solvent comprises N-vinylcaprolactam, N-vinylimidazole, N-vinylpyrrolidone, an acrylate monomer, or a mixture thereof.

[0050] The monomer solvent can be present in the polymerizable liquid in any amount consistent with the objectives described herein. The amount of monomer solvent in the polymerizable liquid can be selected according to several considerations, including, but not limited to, the identity of the polymer additive, the amount of the polymer additive, and / or the identity of the acrylate component. Generally, the monomer solvent can be present in an amount of 2 to 20 weight percent of the polymerizable liquid.

[0051] In a further aspect, a method for printing a three-dimensional article includes providing a polymerizable liquid comprising an acrylate component, a polymer additive, and a monomer solvent for the polymer additive. The polymerizable liquid is irradiated with light to form an article, the article comprising a polymer composite comprising the polymer additive and a copolymer comprising the acrylate component and the monomer solvent. In some embodiments, the article is formed by a layer-by-layer process, where the formation of layers is achieved by depositing and irradiating layers of the polymerizable liquid.

[0052] In some embodiments, a layer of polymerizable liquid can be deposited according to an image of the three-dimensional article in a computer-readable format during formation of the three-dimensional article. The polymerizable liquid can be deposited according to preselected computer-aided design (CAD) parameters. Furthermore, in some cases, one or more layers of the 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 also possible.

[0053] It should further be understood that the methods of printing 3D articles described herein can include so-called "multi-jet" or "stereolithography" 3D printing methods. For example, in some examples, a multi-jet method of printing a 3D article includes selectively depositing layers of a 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 polymerizable liquid with a support material. Any support material not inconsistent with the objectives of the present disclosure can be used.

[0054] Stereolithography can also be used 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. Furthermore, the methods described herein can further include 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 within 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, optionally, raising or lowering the solidified layer of polymerizable liquid is accomplished using an elevator platform disposed within the container of fluid build 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 optionally be accomplished with a wiper or roller.

[0055] In another aspect, printed 3D articles are described herein. In some embodiments, the printed 3D articles are formed from any of the polymerizable liquids described herein. 3D articles formed from the polymerizable liquids described herein can, in some embodiments, have an impact resistance of greater than about 53.38 Joules / meter (1 ft.lb / in.). For example, in some embodiments, the 3D articles can exhibit an impact resistance of about 58.72 to about 106.76 Joules / meter (1.1 to 2 ft.lb / in.). In some embodiments, the impact resistance can be determined according to ASTM D256. In other embodiments, the 3D articles can exhibit an impact resistance of about 21.35 to about 53.38 Joules / meter (0.4 to 1.0 ft.lb / in.).

[0056] Additionally, 3D articles printed from the polymerizable liquids described herein, in some embodiments, can exhibit a flexural modulus in the range of 1400-3500 MPa at 25° C. The flexural modulus of the 3D articles can, in some embodiments, be 1400-1700 MPa or 2000-3200.

[0057] Additionally, 3D articles printed from the polymerizable liquids described herein can, in some embodiments, exhibit a heat deflection temperature (HDT) by DMA ranging from 110° C. to 190° C. In some embodiments, the HDT of the 3D article can range, for example, from 110° C. to 130° C. or from 150° C. to 185° C. As shown in the examples below, the properties of the 3D article can be tuned by varying the compositional parameters of the polymerizable liquid used to print the 3D article.

[0058] These foregoing embodiments are further illustrated in the following non-limiting examples. [Example]

[0059] Table 1 provides formulations of polymerizable liquids according to some embodiments described herein. [Table 1]

[0060] Table 2 shows the physical properties of 3D articles printed using Formulations 1-5, where Formulation 1 was polymerized by exposure to UV light, and Formulations 2-5 were polymerized by exposure to UV light to form copolymers containing acrylate components and monomeric curing agents. Following 3D article formation, crosslinking by the monomeric curing agent was induced by heating at 110°C for 2 hours. [Table 2]

[0061] Table 3 provides formulations of polymerizable liquids according to some embodiments described herein. [Table 3]

[0062] Table 4 shows the physical properties of 3D articles printed using Formulations 6-11. [Table 4]

[0063] Table 5 provides formulations of polymerizable liquids according to some embodiments described herein. [Table 5]

[0064] Table 6 shows the physical properties of 3D articles printed using Formulations 12-19. [Table 6]

[0065] All patent documents mentioned herein are incorporated by reference in their entirety. In accomplishing 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. Other embodiments 1. A polymerizable liquid, acrylate component; polymer additives; and Monomer Curing Agent Including, A polymerizable liquid, wherein the acrylate component and the monomer curing agent are copolymerizable upon exposure to light. 2. The polymerizable liquid of embodiment 1, wherein the polymer additive comprises one or more thermoplastics. 3. The polymerizable liquid of embodiment 2, wherein the thermoplastic material comprises a multi-block copolymer. 4. The polymerizable liquid of embodiment 3, wherein the multi-block copolymer comprises a polyurethane. 5. The polymerizable liquid of embodiment 4, wherein the monomer curing agent comprises an N-vinyl moiety. 6. The polymerizable liquid of embodiment 1, wherein the monomer curing agent comprises one or more imidazoles. 7. The polymerizable liquid of embodiment 1, wherein the monomeric curing agent is present in an amount of 2 to 20 weight percent. 8. The polymerizable liquid of embodiment 1, wherein the monomer curing agent is a solvent for the polymer additive. 9. The polymerizable liquid of embodiment 1, further comprising a cross-linking component. 10. The polymerizable liquid of embodiment 9, wherein the crosslinking component comprises an epoxy resin, an isocyanate component, a polyol component, or a mixture thereof. 11. The polymerizable liquid of embodiment 10, wherein the cross-linking component is coated onto particles. 12. The polymerizable liquid of embodiment 11, wherein the particles are elastomeric. 13. The polymerizable liquid of embodiment 9, wherein the cross-linking component is present in an amount of 15 to 50 weight percent. 14. A method of printing a three-dimensional article, comprising: providing a polymerizable liquid comprising an acrylate component, a polymer additive, and a monomer curing agent; and irradiating the polymerizable liquid with light to form an article. Including, The method, wherein the article comprises a polymer composite comprising the polymer additive and a copolymer comprising the acrylate component and a monomeric curing agent. 15. The method of embodiment 14, wherein the polymerizable liquid is applied in a layer-by-layer process. 16. The method of embodiment 14, wherein the polymer additive comprises a multi-block copolymer. 17. The method of claim 16, wherein the multi-block copolymer comprises a polyurethane. 18. The method of embodiment 14, wherein the polymer additive is present in the layer in an amount of 5 to 30 weight percent. 19. The method of claim 14, wherein the article has an impact resistance greater than 1. 20. The method of embodiment 14, wherein the polymerizable liquid further comprises a cross-linking component. 21. The method of claim 20, wherein the crosslinking component comprises an epoxy resin, an isocyanate component, a polyol component, or a mixture thereof. 22. The method of embodiment 21, wherein the cross-linking moiety is coated onto particles. 23. The method of embodiment 20, further comprising crosslinking the copolymer and polymer additive with a crosslinking component. 24. The method of embodiment 23, wherein the crosslinking is initiated by reaction of the monomeric curing agent with the crosslinking component. 25. The method of embodiment 24, wherein the reaction is activated by heat. 26. The method of claim 23, wherein the article is black. 27. The method of claim 26, wherein no black pigment is added to the polymerizable liquid. 28. A polymerizable liquid, acrylate component; a cross-linking component; and Monomer Curing Agent Including, A polymerizable liquid, wherein the acrylate component and the monomer curing agent are copolymerizable upon exposure to light. 29. The polymerizable liquid of embodiment 28, wherein the monomeric hardener comprises an N-vinyl moiety. 30. The polymerizable liquid of embodiment 28, wherein the monomer curing agent comprises one or more imidazoles. 31. The polymerizable liquid of embodiment 28, wherein the monomeric curing agent is present in an amount of 2 to 20 weight percent. 32. The polymerizable liquid of embodiment 28, wherein the crosslinking component comprises an epoxy resin, an isocyanate component, a polyol component, or a mixture thereof. 33. The polymerizable liquid of embodiment 32, wherein the cross-linking component is coated onto particles. 34. The polymerizable liquid of embodiment 33, wherein the particles are elastomeric. 35. The polymerizable liquid of embodiment 28, wherein the cross-linking component is present in an amount of 15-50 weight percent. 36. A polymerizable liquid comprising: acrylate component; polymer additives; and Monomer solvent for the polymer additive Including, A polymerizable liquid, wherein the monomer solvent and acrylate components are copolymerizable upon exposure to light. 37. The polymerizable liquid of embodiment 36, wherein the polymer additive comprises one or more thermoplastics. 38. The polymerizable liquid of embodiment 37, wherein the thermoplastic material comprises a multi-block copolymer. 39. The polymerizable liquid of embodiment 38, wherein the multi-block copolymer comprises a polyurethane. 40. The polymerizable liquid of embodiment 36, wherein the monomer solvent comprises N-vinylcaprolactam, N-vinylimidazole, N-vinylpyrrolidone, an acrylate monomer, or a mixture thereof. 41. The polymerizable liquid of embodiment 36, wherein the monomer solvent is present in an amount from 2 to 20 weight percent. 42. A method of printing a three-dimensional article, comprising: providing a polymerizable liquid comprising an acrylate component, a polymer additive, and a monomer solvent for said polymer additive; and irradiating the polymerizable liquid with light to form an article. Including, The method, wherein the article comprises a polymer composite comprising the polymer additive and a copolymer comprising the acrylate component and a monomer solvent. 43. The method of embodiment 42, wherein the polymerizable liquid is applied in a layer-by-layer process. 44. The method of embodiment 42, wherein the polymer additive comprises a thermoplastic polyurethane. 45. A polymerizable liquid comprising: acrylate component; Thermoplastic polyurethane; a cross-linking component; and Monomer Curing Agent Including, A polymerizable liquid, wherein the acrylate component and the monomer curing agent are copolymerizable upon exposure to light. 46. ​​The polymerizable liquid of embodiment 45, wherein the thermoplastic polyurethane is present in an amount of 5 to 30 weight percent of the polymerizable liquid. 47. The polymerizable liquid of embodiment 45, wherein the monomeric curing agent comprises an amine moiety for participating in a reaction with the cross-linking component. 48. A method of printing a three-dimensional article, comprising: providing a polymerizable liquid comprising an acrylate component, a thermoplastic polyurethane, a crosslinking component, and a monomeric curing agent; irradiating the polymerizable liquid with light to form an article; and crosslinking the copolymer with the thermoplastic polyurethane via reaction of the monomeric curative with the crosslinking component. Including, The method, wherein the article comprises a polymer composite comprising the thermoplastic polyurethane, a crosslinking component, and a copolymer comprising the acrylate component and a monomeric curing agent. 49. The method of claim 48, wherein the crosslinking is induced by heating the article.

Claims

1. A polymerizable liquid, acrylate component; a cross-linking component coated on the particle; and Monomer Hardener Including, the acrylate component and the monomer curing agent are copolymerizable upon exposure to light; The crosslinking component comprises an epoxy resin, an isocyanate component, a polyol component, or a mixture thereof. A polymerizable liquid characterized by:

2. 10. The polymerizable liquid of claim 1, wherein the monomeric hardener comprises an N-vinyl moiety.

3. The polymerizable liquid of claim 1 , wherein the monomer curing agent comprises one or more imidazoles.

4. 10. The polymerizable liquid of claim 1, wherein the monomeric curing agent is present in an amount of 2 to 20 weight percent.

5. The polymerizable liquid of claim 1 , wherein the particles are elastomeric.

6. 10. The polymerizable liquid of claim 1, wherein the cross-linking component is present in an amount of 15 to 50 weight percent.

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