Method and composition for additive manufacturing with high water permeability

Abstract

To provide improved compositions or build materials for 3D printing having improved properties related to specific end uses that may require high strength and / or exposure to specific environmental conditions.SOLUTION: Described herein are build materials and methods for 3D printing. In one aspect, the build material includes an acrylate component, a photoinitiator component, and a porogen component, where the porogen component is water soluble. In some embodiments, the porogen component is present in the build material in an amount of 55-75 wt. % based on a total weight of the build material.SELECTED DRAWING: Figure 1A

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority pursuant to 35 U.S.C. Section 119 to U.S. Provisional Patent Application No. 63 / 633,255, filed April 12, 2024, which is incorporated herein by reference in its entirety. [Technical Field]

[0002] The present invention relates generally to systems, methods, and compositions used in three-dimensional (3D) printing or additive manufacturing. [Background technology]

[0003] Additive manufacturing systems or three-dimensional (3D) printers use build materials, sometimes referred to as inks or polymerizable liquids, to form various 3D objects, articles, or parts according to a computer-generated file or other digital representation of the object, article, or part. In some examples, the build material is solid at ambient temperature and is converted to a liquid at an elevated jetting temperature. In other examples, the build material is liquid at ambient temperature. The build material can be formed into a 3D object in various ways, for example, by jetting or depositing the build material onto a substrate. The build material can also be selectively cured, solidified, or otherwise transformed during printing. For example, some 3D printers form 3D articles from a reservoir, vat, or container of fluid or powder build material. In some cases, a binder material or a laser, digital light processing (DLP) light source, or other light source is used to selectively solidify or consolidate layers of the build material in stages to provide the 3D article.

[0004] Additive manufacturing or 3D printing systems can be used to form articles for a variety of end uses. However, the end uses of some articles formed by additive manufacturing may be limited by the build materials used to form the articles. For example, some articles formed by additive manufacturing may not withstand high temperatures, may not dissolve or disperse or be removable in the desired manner, and / or may not provide sufficient mechanical strength for certain end uses. Biologically relevant applications may be particularly difficult to achieve. Summary of the Invention [Problem to be solved by the invention]

[0005] Thus, there is a need for improved compositions or build materials for 3D printing that have improved properties, particularly related to certain end uses that may require high strength and / or exposure to specific environmental conditions. [Means for solving the problem]

[0006] In one aspect, described herein are build materials or compositions for use in 3D printers. In some embodiments, the build materials described herein include an acrylate component; a photoinitiator component; and a porogen component. In some such embodiments, the porogen component is water-soluble. In some cases, the porogen component is present in the build material in an amount of 55-75 wt. %, based on the total weight of the build material.

[0007] Additionally, in some embodiments, the porogen component is miscible in water at 20° C. In some examples, the porogen component has a solubility of 20% to 100% in water at 20° C. In some cases, the porogen component has a solubility of at least 150 g / L in water at 20° C. Furthermore, in other embodiments, the porogen component has a Hansen solubility parameter δ d is 14-17 (J / cm 3 ) 1 / 2 , Hansen solubility parameter δ p is 2 to 8 (J / cm3 ) 1 / 2 , Hansen solubility parameter δ h is 10-15 (J / cm 3 ) 1 / 2 Additionally, in some embodiments, the porogen component has a surface tension of 25-30 dynes / cm at 25° C. when measured according to ASTM D 1331-20.

[0008] In some examples, the porogen component of the build materials described herein comprises a glycol ether. In some such examples, the glycol ether comprises propylene glycol methyl ether or tripropylene glycol methyl ether.

[0009] In some embodiments, the acrylate component of the build materials described herein comprises a urethane ether. In some such embodiments, the urethane acrylate comprises a polyether urethane acrylate. In other such embodiments, the urethane acrylate comprises a polyurethane acrylate. In some cases, the acrylate component is present in the build material in an amount of 20-40 wt. % based on the total weight of the build material.

[0010] Additionally, in some cases, the photoinitiator component of the build materials described herein is present in the build material in an amount of 0.5 to 2 wt. %, based on the total weight of the build material. In some embodiments, the photoinitiator component comprises benzoylphosphine oxide. In some examples, the build material further comprises a colorant.

[0011] In another aspect, described herein are methods of forming three-dimensional articles by additive manufacturing. In some embodiments, such methods include providing a build material or composition described herein, and printing and curing the build material or composition to form a printed three-dimensional article. Further, in some cases, the build material or composition is provided in a layer-by-layer process. In some embodiments, the method further includes washing the printed three-dimensional article with an aqueous solution.

[0012] In another aspect, described herein are printed three-dimensional articles, including articles formed from the build materials or compositions described herein. In some cases, the printed three-dimensional articles are -17 ~10 -14 m 2 or 10 -16 ~10 -14 m 2 In another embodiment, the article is a medical implant.

[0013] These and other embodiments are described in further detail in the detailed description that follows. [Brief explanation of the drawings]

[0014] [Figure 1A] FIG. 1 is a schematic exploded perspective view of a Franz cell according to one embodiment described herein. [Figure 1B] 1B is an unexploded perspective view of the Franz cell of FIG. 1A when the cell is assembled. [Figure 2] FIG. 1 is a perspective view of a Franz cell set up to measure the water permeability of an article printed using the compositions and / or methods described herein, using a Franz cell at 60 mmHg pressure, according to one embodiment described herein. [Figure 3] FIG. 1 is a perspective view of a Franz cell set up to measure the water permeability of an article printed using the compositions and / or methods described herein, using a Franz cell at 30 mmHg pressure, according to one embodiment described herein. DETAILED DESCRIPTION OF THE INVENTION

[0015] 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 disclosure. Many modifications and adaptations will be readily apparent to those skilled in the art without departing from the spirit and scope of the present disclosure.

[0016] Furthermore, 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 deemed 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, 1 to 4, 3 to 7, 4.7 to 10.0, 3.6 to 7.9, or 5 to 8.

[0017] All ranges disclosed herein should also be considered to include the endpoints of the range, unless otherwise specified. For example, a range "between 5 and 10," "from 5 to 10," or "5 to 10" should generally be considered to include the endpoints 5 and 10.

[0018] Furthermore, when the term "up to" is used in connection with an amount or quantity, it is understood that the amount is at least a detectable amount or quantity (i.e., the amount is a non-zero amount). For example, a substance present in an amount "up to" a particular amount can be present in an amount from a detectable (or non-zero) amount up to and including the particular amount.

[0019] The article "a" or "an" should also be understood to refer to "at least one," unless the context of the particular use requires otherwise.

[0020] Terms such as "three-dimensional printing system," "three-dimensional printer," and "printing" generally describe various solid freeform manufacturing techniques for creating three-dimensional articles or objects by stereolithography (SLA), digital light processing (DLP), selective deposition, jetting, fused deposition modeling (FDM), multi-jet modeling (MJM), and other additive manufacturing techniques currently known or that may become known in the art that use build materials to fabricate three-dimensional objects.

[0021] I. 3D printing materials In one aspect, described herein are build materials (or compositions) for use in a 3D printer or additive manufacturing system. In some embodiments, the build materials described herein include an acrylate component; a photoinitiator component; and a porogen component. In some such embodiments, the porogen is water-soluble. In some cases, the porogen component is present in the build material in an amount of 55-75% by weight, based on the total weight of the build material. Other components may also be present in some embodiments of the build materials or compositions described herein.

[0022] Referring now in more detail to the specific components of the build materials or compositions described herein, the build materials or compositions described herein include a porogen component. In some embodiments, the porogen component described herein includes a material that forms or generates pores in an article printed or formed from the build materials described herein. For example, in some instances, without intending to be bound by theory, the porogen component forms a separate phase within the build material (including during additive manufacturing processes described herein), such as porogen "bubbles." Thus, in some such embodiments, the porogen component can be removed from the finished article (e.g., by washing with the methods described herein), leaving behind cavities, voids, or pores.

[0023] Additionally, in some embodiments, the porogen component of the build materials described herein is water soluble. In other embodiments, the porogen component is miscible in water at 20° C. In some cases, the porogen component has a solubility of 20% to 100% in water at 20° C. In other examples, the porogen may have a solubility of 20% to 90%, 20% to 80%, 20% to 70%, 20% to 60%, 20% to 50%, 20% to 40%, 20% to 30%, 30% to 100%, 30% to 90%, 30% to 80%, 30% to 70%, 30% to 60%, 30% to 50%, 30% to 40%, 40% to 100%, 40% to 90%, 40% to 80%, 40% to 80%, 40% to 9 ... In some embodiments, the porogen component has a solubility of 0% to 70%, 40% to 60%, 40% to 50%, 50% to 100%, 50% to 90%, 50% to 80%, 50% to 70%, 50% to 60%, 60% to 100%, 60% to 90%, 60% to 80%, 60% to 70%, 70% to 100%, 70% to 90%, 70% to 80%, 80% to 100%, 80% to 90%, or 90% to 100%. Additionally, in some embodiments, the porogen component has a solubility in water at 20° C. of at least 100 g / L, 125 g / L, 150 g / L, 175 g / L, or 200 g / L.

[0024] Additionally, in some instances, the porogen component may have a viscosity of 14 to 17 (J / cm 3 ) 1 / 2 Hansen solubility parameter δ d (dispersion solubility parameter). In such a case, the porogen component has a dispersibility of 14 to 15 (J / cm 3 ) 1 / 2 , 16-17 (J / cm 3 ) 1 / 2 , or 15-16 (J / cm 3 ) 1 / 2 Hansen solubility parameter δ d Further, in some embodiments, the porogen has a viscosity of 2 to 8 (J / cm 3 ) 1 / 2 Hansen solubility parameter δ p (polar solubility parameter). In some such implementations, the porogen has a polar solubility parameter of 2 to 6 (J / cm 3 ) 1 / 2 , 2 to 4 (J / cm 3 )1 / 2 , 4 to 8 (J / cm 3 ) 1 / 2 , 4 to 6 (J / cm 3 ) 1 / 2 , or 6 to 8 (J / cm 3 ) 1 / 2 Hansen solubility parameter δ p Furthermore, in some cases, the porogen has a viscosity of 10 to 15 (J / cm 3 ) 1 / 2 Hansen solubility parameter δ h (hydrogen bond solubility parameter). In some such embodiments, the porogen has a solubility parameter of 10 to 14 (J / cm 3 ) 1 / 2 , 10~13(J / cm 3 ) 1 / 2 , 10~12(J / cm 3 ) 1 / 2 , 10-11 (J / cm 3 ) 1 / 2 , 11-15 (J / cm 3 ) 1 / 2 , 11-14 (J / cm 3 ) 1 / 2 , 11-13 (J / cm 3 ) 1 / 2 , 11-12 (J / cm 3 ) 1 / 2 , 12-15(J / cm 3 ) 1 / 2 , 12-14 (J / cm 3 ) 1 / 2 , 12-13 (J / cm 3 ) 1 / 2 , 13-15 (J / cm 3 ) 1 / 2 , 13-14 (J / cm 3 ) 1 / 2 , or 14-15 (J / cm 3 ) 1 / 2 Hansen solubility parameter δ h It has.

[0025] In some embodiments, the surface tension of the porogen component is 20-35 dynes / cm at 25° C. when measured according to ASTM D1331-20. In some cases, the surface tension of the porogen component is 25-30 dynes / cm at 25° C. when measured according to ASTM D1331-20. In still other examples, the surface tension of the porogen component is 20-25, 20-30, 25-35, or 30-35 dynes / cm at 25° C. when measured according to ASTM D1331-20.

[0026] Any porogen component not inconsistent with the technical objectives of the present disclosure can be used in the build materials described herein. In some embodiments, the porogen component comprises a glycol ether. In some such embodiments, the glycol ether comprises propylene glycol methyl ether or tripropylene glycol methyl ether. Other chemical species can also be used as or in the porogen components described herein.

[0027] The porogen component can be present in the compositions or build materials described herein in any amount consistent with the technical objectives of the present disclosure. In some cases, the porogen component is present in the build material in an amount of 55-75 wt.%, based on the total weight of the build material. In some such examples, the porogen component is present in the build material in an amount of 55-70 wt.%, 55-65 wt.%, 55-60 wt.%, 60-80 wt.%, 60-75 wt.%, 60-70 wt.%, 60-65 wt.%, 65-80 wt.%, 65-75 wt.%, 65-70 wt.%, 70-80 wt.%, 70-75 wt.%, or 75-80 wt.%, based on the total weight of the build material.

[0028] Regarding other components of the composition or build material, the composition or build material described herein includes an acrylate component. Any acrylate component consistent with the technical objectives of the present disclosure may be used. In particular, it is observed that, for reference purposes herein, the "acrylate" component may include one or more chemical species containing at least one acrylate, (meth)acrylate, acrylamide, or (meth)acrylamide moiety or functional group. Furthermore, the term "(meth)acrylate" should be understood to include acrylate or methacrylate, or a mixture or combination thereof. Similarly, the term "(meth)acrylamide" should be understood to include chemical species containing at least one acrylamide or (meth)acrylamide moiety or functional group. In some cases, the acrylate component includes a (meth)acrylate monomer, a (meth)acrylate oligomer, or a mixture thereof.

[0029] The (meth)acrylate monomers and / or (meth)acrylate oligomers described herein can include monofunctional, difunctional, trifunctional, tetrafunctional, pentafunctional, or higher functional acrylate species. For reference purposes herein, a "monofunctional" acrylate species includes a species containing one acrylate moiety. Similarly, a "difunctional" acrylate species includes a species containing two acrylate moieties; a "trifunctional" acrylate species includes a species containing three acrylate moieties; a "tetrafunctional" acrylate species includes a species containing four acrylate moieties; and a "pentafunctional" curable species includes a species containing five acrylate moieties. Thus, in some embodiments, the monofunctional acrylate component of the compositions described herein comprises a mono(meth)acrylate, the difunctional acrylate component of the compositions described herein comprises a di(meth)acrylate, the trifunctional acrylate component of the compositions described herein comprises a tri(meth)acrylate, the tetrafunctional acrylate component of the compositions described herein comprises a tetra(meth)acrylate, and the pentafunctional acrylate component of the compositions described herein comprises a penta(meth)acrylate. Other monofunctional, difunctional, trifunctional, tetrafunctional, and pentafunctional acrylate species can also be used.

[0030] Additionally, the mono-, di-, tri-, tetra-, and penta-functional (meth)acrylates may optionally contain relatively low molecular weight species, i.e., (meth)acrylate monomers (e.g., species having a molecular weight of less than 300, less than 200, or less than 100), or relatively high molecular weight species, i.e., (meth)acrylate oligomer components (e.g., species having a molecular weight (e.g., weight average molecular weight in the case of species having a molecular weight distribution) greater than 300, greater than 400, greater than 500, or greater than 600, and optionally less than 10,000).

[0031] Further, in some embodiments, the (meth)acrylate monomer has a viscosity of 500 centipoise (cP) or less at 25°C, as measured according to ASTM D2983, while the (meth)acrylate oligomer has a viscosity of 1000 cP or more at 25°C, as measured according to ASTM D2983.

[0032] As noted above, the build materials described herein can include (meth)acrylate monomers (e.g., as part of the acrylate component). The (meth)acrylate monomers can include any (meth)acrylate monomers not inconsistent with the objectives of the present disclosure. For example, in some cases, the (meth)acrylate monomers include one or more (meth)acrylates and / or one or more (meth)acrylamides. Furthermore, in some embodiments described herein, the one or more (meth)acrylates and / or one or more (meth)acrylamides are hydrophilic or water-soluble. A "water-soluble" species or substance, for purposes of reference herein, has a solubility in water (or an acidic or basic aqueous solution as further described herein) of at least 1 gram per liter of water (or aqueous solution) at 25°C. In some cases, the water-soluble species or substance has a solubility of at least 5 g / L, at least 10 g / L, or at least 100 g / L at 25°C.

[0033] In some embodiments described herein, the (meth)acrylate monomer comprises a hydrophilic or water-soluble mono-, di-, and / or tri(meth)acrylate species. The (meth)acrylate monomer may comprise, for example, one or more of hydroxyalkyl (meth)acrylate (e.g., hydroxypropyl acrylate), hydroxyalkyl (meth)acrylamide (e.g., N-hydroxyethyl acrylamide), ethoxylated trimethylolpropane triacrylate ("TAC" or trimethylolpropane ethoxylate triacrylate), acryloylmorpholine, and various combinations or mixtures thereof. In some embodiments, the hydroxyalkyl (meth)acrylate comprises hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, and / or mixtures thereof.

[0034] The (meth)acrylate monomers of the build materials described herein can also include a poly(ethylene glycol) diacrylate (PEGDA) component. As used herein, referring to a poly(ethylene glycol) diacrylate component, the PEGDA component can include a single poly(ethylene glycol) diacrylate species or multiple poly(ethylene glycol) diacrylate species with different molecular weights. In some embodiments, the PEGDA species have a weight-average molecular weight of 0.1 kilodaltons (kDa) to 20 kDa, or 0.2 to 20 kDa.

[0035] The molecular weight of an individual species of PEGDA can be, for example, within one or more ranges shown in Table 1. [Table 1]

[0036] Any combination or mixture of poly(ethylene glycol) diacrylates of different molecular weights is contemplated. In some cases, the PEGDA component comprises a mixture of two or more PEGDA species, each having a weight average molecular weight of 0.5 to 5 kDa.

[0037] Additionally, in some cases, the (meth)acrylate monomer of the compositions described herein comprises a cyclocarbonate (meth)acrylate monomer. In some such examples, the cyclocarbonate (meth)acrylate monomer has the structure of Formula I: [ka] wherein Y is a linear or branched C1-C6 alkylene moiety; and wherein Z is H or CH3.

[0038] For reference purposes herein, a "Cn-Cm alkylene moiety" (e.g., a "C1-C4 alkylene moiety") is understood to be a divalent saturated aliphatic radical having from "n" to "m" carbon atoms (e.g., 1 to 4 carbon atoms, but not more than 4 carbon atoms). In some preferred embodiments, Y is a linear or branched C1-C4 alkylene moiety, particularly preferably, for example, CH2. Further, in some embodiments, Z is H. Furthermore, in some instances, Y is CH2 and Z is H. Thus, in some instances, the cyclocarbonate (meth)acrylate monomer of the compositions described herein has the structure of Formula II: [ka]

[0039] It should be understood that the (meth)acrylate monomers of the build materials described herein can include combinations of monomer species, such as combinations of the (meth)acrylate and / or (meth)acrylamide species described above. For example, in some cases, the (meth)acrylate monomers include one or more hydroxyalkyl (meth)acrylates, one or more poly(ethylene glycol) acrylates, one or more poly(ethylene glycol) diacrylates, one or more hydroxyalkyl (meth)acrylamides, one or more cyclocarbonate (meth)acrylates, or combinations of two or more of the foregoing. Thus, the present disclosure contemplates many combinations and compositions of (meth)acrylate monomers that may be included in exemplary implementations, but which are not explicitly listed herein.

[0040] The build materials or compositions described herein may also optionally include a (meth)acrylate oligomer (e.g., as part of the acrylate component of the build material). Any (meth)acrylate oligomer species consistent with the technical objectives of the present disclosure may be used. In some preferred embodiments, the (meth)acrylate oligomer includes one or more hydrolyzable oligomer species. For purposes of reference herein, a "hydrolyzable" oligomer species includes at least one hydrolyzable bond. In some cases, the hydrolyzable bond is part of a repeat unit of the oligomer. For example, in some instances, the hydrolyzable oligomer species includes one or more urethane linkages, one or more ester linkages, or one or more carbonate linkages in the backbone of the oligomer species. As one skilled in the art will appreciate, such bonds can be relatively easily hydrolyzed by water when exposed to water or an aqueous solution described herein for the time and temperature described herein.

[0041] Furthermore, in some preferred embodiments, the (meth)acrylate oligomers may be not only hydrolyzable but also difunctional or higher functional. Furthermore, in some preferred embodiments, a majority of the total amount of (meth)acrylate oligomers is difunctional or higher functional. For example, in some cases, at least 60% by weight, at least 70% by weight, at least 80% by weight, or at least 90% by weight of the (meth)acrylate oligomer component is difunctional or higher functional, the aforementioned weight percentages being based on the total amount of the (meth)acrylate oligomer component.

[0042] In some embodiments of the build materials described herein, the (meth)acrylate oligomer material comprises a urethane acrylate oligomer, a urethane methacrylate oligomer, a polyether urethane oligomer, an aliphatic polyester urethane acrylate oligomer, or a combination of two or more of the foregoing. In some such embodiments, the urethane acrylate can comprise a polyether urethane acrylate or a polyurethane acrylate. In some examples, the polyether urethane acrylate can be monofunctional or difunctional. Furthermore, in some cases, the (meth)acrylate oligomer can comprise an aliphatic urethane diacrylate oligomer.

[0043] Non-limiting examples of commercially available (meth)acrylate oligomers useful in some embodiments described herein include: 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; an aliphatic urethane diacrylate oligomer available from IGM Resins under the trade name PHOTOMER 6210; an aliphatic urethane diacrylate oligomer available from IGM Resins under the trade name PHOTOMER 6710; a multifunctional acrylate oligomer available from DYMAX Corporation under the trade name BR-952; an aliphatic polyether urethane acrylate available from DYMAX Corporation under the trade name BR-371S; and a polyether urethane methacrylate available from DYMAX Corporation under the trade name BR-541MD. Other commercially available oligomeric curable materials may also be used.

[0044] Urethane (meth)acrylates suitable for use in the build materials described herein can be prepared by known methods, typically by reacting a hydroxyl-terminated urethane with acrylic or methacrylic acid to obtain the corresponding urethane (meth)acrylate, or by reacting an isocyanate-terminated prepolymer with a hydroxyalkyl acrylate or methacrylate to obtain the urethane (meth)acrylate. Suitable processes are disclosed, inter alia, in EP-A 114 982 and EP-A 133 908. The weight-average molecular weight of such (meth)acrylate oligomers can be, in some cases, about 500 to 6,000. Urethane (meth)acrylates are commercially available from SARTOMER under the product names CN980, CN981, CN975, and CN2901. In some embodiments, urethane acrylate oligomers are used in the build materials described herein. Suitable urethane acrylates include difunctional aliphatic urethane acrylates available from DYMAX Corporation under the trade names BR-741 and BR-970. In some embodiments, the (meth)acrylate oligomer comprises an aliphatic polyester urethane acrylate or an aliphatic polyether urethane acrylate. Commercially available products of these oligomer species are available from DYMAX Corporation under the trade names BR-7432 and BR-543, respectively.

[0045] The acrylate component of the build materials or compositions described herein can be present in any amount consistent with the technical objectives of the present disclosure. In some embodiments, for example, the acrylate component can be present in an amount of 1-40 wt%, 1-35 wt%, 1-30 wt%, 1-20 wt%, 5-40 wt%, 5-35 wt%, 5-30 wt%, 5-20 wt%, 5-15 wt%, 10-40 wt%, 10-35 wt%, 10-30 wt%, 10-20 wt%, 15-40 wt%, 15-35 wt%, 15-30 wt%, 15-25 wt%, 20-40 wt%, 20-35 wt%, 20-30 wt%, 25-40 wt%, or 25-35 wt%, based on the total weight of the composition.

[0046] The build materials or compositions described herein also include a photoinitiator component for initiating polymerization of one or more components of the build material or composition upon exposure to light of an appropriate wavelength. Any photoinitiator not inconsistent with the objectives of the present disclosure can be used in the build materials or compositions described herein. In some embodiments, for example, the photoinitiator component includes an alpha-cleavage (unimolecular decomposition process) photoinitiator or a hydrogen-abstraction photosensitizer-tertiary amine synergist that can be used to absorb light at about 250 nm to about 400 nm, about 250 nm to about 405 nm, or about 300 nm to about 385 nm to generate free radicals. Examples of alpha-cleavage photoinitiators include 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) and diethylaminoethyl methacrylate.

[0047] Further, in some examples, photoinitiators include benzoins including benzoin, benzoin ethers such as benzoin methyl ether, benzoin ethyl ether, and benzoin isopropyl ether, benzoin phenyl ether, and benzoin acetate, acetophenone, acetophenones including 2,2-dimethoxyacetophenone and 1,1-dichloroacetophenone, benzil, benzil ketals such as benzil dimethyl ketal and benzil diethyl ketal, anthraquinones including 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, and 2-aminoanthraquinone, triphenylphosphine, benzoylphosphine oxides such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide (Lucirin TPO), benzophenones such as benzophenone and 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 ketone, or 1-hydroxyphenyl ketones such as 1-hydroxycyclohexyl phenyl ketone, phenyl 1-hydroxyisopropyl ketone, and 4-isopropylphenyl 1-hydroxyisopropyl ketone.

[0048] Suitable photoinitiators can also include those usable with HeCd laser radiation sources, including acetophenone, 2,2-dialkoxybenzophenone, 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 usable with Ar laser radiation sources, including benzil ketals, such as benzil dimethyl ketal. In some embodiments, suitable photoinitiators include α-hydroxyphenyl ketone, benzil dimethyl ketal, or 2,4,6-trimethylbenzoyldiphenylphosphine oxide, or mixtures thereof.

[0049] Another class of photoinitiators that can be included in the compositions described herein includes ionic dye-counterion compounds that can absorb actinic radiation and generate free radicals for polymerization initiation. In some embodiments, compositions 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.

[0050] In some cases, photoinitiators that can be included in the build materials or compositions described herein include water-soluble pyrrolidones or phosphine oxides, such as monoacylphosphine oxide (MAPO) salts or bisacylphosphine oxide (BAPO) salts, which can optionally be sodium or lithium MAPO or BAPO salts. In some embodiments, the photoinitiators included in the build materials or compositions described herein have the structure of Formula III or Formula IV: [ka] [ka] In the formula, X is Na or Li, and R1 to R 10 is independently H, CH, or CHCH. For example, in some preferred embodiments, R, R, and R in Formula III are each CH, and R, R, R, R, R, R, and R 10is H. Such species may be referred to herein as "NaP," "Na-TPO," "sodium TPO," or "sodium TPO-L" when X is Na, and as "LiP," "Li-TPO," "lithium TPO," or "lithium TPO-L" when X is Li. In other preferred embodiments, R, R, R, R, R, and R in Formula IV are 10 is CH3, and each of R2, R4, R7, and R9 is H. Such species may be referred to herein as BAPO-ONa when X is Na, and as BAPO-OLi when X is Li. Furthermore, with reference to Formula III and Formula IV above, it should also be understood that these structures represent resonance structures, or (for convenience of depiction) structures in which the PO single bond and PO double bond "swap places" in the depiction of the structure (e.g., the PO double bond points "up" instead of "down" as described above).

[0051] The photoinitiator component can be present in the build materials or compositions described herein in any amount consistent with the objectives of the present disclosure. In some embodiments, the photoinitiator component is present in the build material or composition in an amount of up to about 7%, up to about 5%, up to about 3%, or up to about 2% by weight, based on the total weight of the build material or composition. In some cases, the photoinitiator is present in an amount of about 0.1-7%, 0.1-5%, 0.1-3%, 0.1-2%, 0.5-5%, 0.5-3%, 0.5-2%, 1-7%, 1-5%, or 1-3% by weight, based on the total weight of the build material or composition.

[0052] It should be further understood that the amounts (weight percent) described in the immediately preceding paragraph refer to non-oligomeric and non-polymeric photoinitiators. That is, the amounts described above refer to "monomeric" or "molecular" photoinitiators, which may have a molecular weight of less than 400, for example. However, it should also be understood that oligomeric or polymeric photoinitiators may be used in the compositions and methods described herein. However, in such cases (when oligomeric or polymeric photoinitiators are used), the amounts (weight percent) described above are calculated without taking into account the weight of the oligomeric or polymeric portion or portions of the oligomeric or polymeric photoinitiator. In other words, to determine the total amount (weight percent) of oligomeric or polymeric photoinitiator present in a composition, the calculation (specifically, the molecular weight) is based solely on the molecular weight of the photoactive portion of the photoinitiator, and not (for purposes of this disclosure) on the molecular weight of the remaining portions or repeat units of the oligomeric or polymeric photoinitiator.

[0053] The build materials or compositions described herein may optionally further comprise one or more photosensitizers. Generally, such sensitizers may be added to the build material to enhance the effectiveness of one or more photoinitiators that may also be present. In some cases, the sensitizer comprises isopropylthioxanthone (ITX) or 2-chlorothioxanthone (CTX).

[0054] The sensitizer may be present in the composition in any amount consistent with the technical objectives of the present disclosure. In 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 composition. However, in other cases, the compositions described herein exclude such sensitizers.

[0055] Considering another possible component of the build materials or compositions described herein, the build materials or compositions described herein may further include a colorant. Such colorants of the build materials described herein may be particulate colorants, such as particulate pigments, or molecular colorants, such as molecular dyes. Any such particulate or molecular colorant not inconsistent with the technical objectives of the present disclosure may be used. In some cases, for example, the colorant of the composition includes an inorganic pigment, such as TiO and / or ZnO. In some embodiments, the colorant of the composition may be any of RGB, sRGB, CMY, CMYK, L * a * b * or colorants for use in Pantone® color schemes. Additionally, in some cases, the particulate colorants described herein have an average particle size of less than about 5 μm, or less than about 1 μm. In some examples, the particulate colorants described herein have an average particle size of less than about 500 nm, e.g., less than about 400 nm, less than about 300 nm, less than about 250 nm, less than about 200 nm, or less than about 150 nm. In some examples, the particulate colorants have an average particle size of about 50-5000 nm, about 50-1000 nm, or about 50-500 nm.

[0056] The colorant may be present in any amount consistent with the technical objectives of the present disclosure in the compositions described herein. In some cases, the colorant is present in the composition in an amount of up to about 2% by weight, or in an amount of about 0.005-2%, 0.01-2%, 0.01-1.5%, 0.01-1%, 0.01-0.5%, 0.1-2%, 0.1-1%, 0.1-0.5%, or 0.5-1.5% by weight, based on the total weight of the composition. In some embodiments, the compositions described herein exclude the colorants described above.

[0057] The molding materials or compositions described herein can be produced by any method consistent with the technical objectives of the present disclosure. In some embodiments, for example, methods for preparing the compositions described herein include mixing the components of the composition, optionally melting the mixture, and filtering the (optionally melted) mixture. In some cases, the components are mixed and optionally melted at a temperature of about 25°C to about 35°C, or at a temperature within a range of 25°C to 55°C, 35°C to 65°C, or 45°C to 75°C. In some instances where melting one or more solid components of the composition is desirable or necessary, mixing and / or melting can be carried out at a temperature within a range of about 75°C to about 85°C. In some embodiments, the compositions described herein are produced by placing all of the components of the composition in a reaction vessel, optionally heating the resulting mixture, and stirring the resulting mixture at a temperature within a range of about 25°C to about 75°C or about 75°C to about 85°C. Stirring (and optionally heating) is continued until the mixture reaches a substantially homogenized liquid (or molten) state. Generally, the liquid (or molten) mixture can be filtered while in a fluid state to remove large, undesirable particles that may interfere with the jetting, extrusion, or other printing process. The filtered mixture is then cooled to ambient temperature (if cooling is required) and stored until ready for use in the 3D printing system.

[0058] II. Methods for Forming 3D Articles by Additive Manufacturing In another aspect, methods of forming or "printing" 3D articles or objects by additive manufacturing are described herein. The methods of forming 3D articles or objects described herein can include forming the 3D article layer-by-layer from multiple layers of the compositions described herein. In such cases, the compositions can be used as build materials. In some embodiments, the compositions described herein can also be used as support materials. The methods of forming 3D articles by additive manufacturing can also include forming the object by methods other than layer-by-layer. Any of the compositions described above in Section I can be used in the methods described herein. For example, in some embodiments, the methods described herein include providing a composition, the composition comprising an acrylate component; a photoinitiator component; and a porogen component. In some such embodiments, the porogen component is water-soluble. In some cases, the porogen component is present in the build material in an amount of 55-75% by weight, based on the total weight of the build material.

[0059] In some examples, the methods described herein include providing a build material comprising the composition described above and selectively curing portions of the build material using incident curing radiation having a Gaussian distribution of wavelengths and a peak wavelength at wavelength λ. Furthermore, in some embodiments described herein, the build material is selectively cured according to a digital file or image of the desired article, e.g., according to preselected computer-aided design (CAD) parameters. Furthermore, in some cases, one or more layers of the build material 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 10 μm to about 40 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.

[0060] The printing processes described herein can be used to provide 3D articles printed from the build materials described herein with high feature resolution. For reference purposes herein, the "feature resolution" of an article can be the smallest controllable physical feature size of the article, or the pixel or voxel size of the printing process, with "pixel" and "voxel" understood to refer to the CAD parameters or other digital model of the article. In some embodiments, the printed articles described herein have an average voxel size that averages more than 50 μm per side (e.g., when the average voxel size corresponds to a volume having an average length in all three dimensions of 50-100 μm, 50-75 μm, 60-100 μm, 60-80 μm, or 60-70 μm). In other cases, the printed articles described herein have an average voxel size that is, on average, less than 50 μm, less than 40 μm, less than 30 μm, or less than 20 μm per side (e.g., where the average voxel size corresponds to a volume having an average length in all three dimensions of 10-45 μm, 10-40 μm, 10-30 μm, 10-25 μm, 10-20 μm, 15-45 μm, or 15-40 μm).

[0061] Furthermore, it should be understood that the methods of printing 3D articles described herein can include, for example, MJP, DLP, or SLA 3D printing methods. For example, in some examples, an MJP method of printing a 3D article includes selectively depositing a layer of a build material described herein in a fluid state 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 build material with a support material. Any support material not inconsistent with the objectives of the present disclosure can be used.

[0062] The methods described herein may include curing the layer of build material, including with the curing radiation described above (e.g., curing radiation having a peak wavelength λ). Additionally, the curing may include polymerizing one or more polymerizable moieties or functional groups of one or more components of the build material. In some cases, a deposited layer of build material is cured prior to deposition of another or adjacent layer of build material. Additionally, curing one or more layers of deposited build material is, in some embodiments, performed by exposing the one or more layers to electromagnetic radiation, such as UV light, visible light, or infrared light, as described above.

[0063] Furthermore, it should be noted that the wavelength λ used to cure materials according to the methods described herein can be any wavelength consistent with the objectives of the present disclosure. For example, in some cases, λ is a wavelength in the ultraviolet (UV) or visible region of the electromagnetic spectrum. In some cases, the peak wavelength λ is in the infrared (IR) region of the electromagnetic spectrum. In some embodiments, the wavelength λ is 250 nm to 400 nm, 300 nm to 385 nm, or 385 nm to 405 nm. In other cases, the wavelength λ is 600 nm to 800 nm, or 900 nm to 1.3 μm. However, the exact wavelength λ is not particularly limited.

[0064] Furthermore, it should be understood that the 3D article printing methods described herein may further include a step of washing the formed (printed) 3D article. In some embodiments, the article may be rinsed with an aqueous solution, alcohol, or a mixture thereof. Any aqueous solution not inconsistent with the technical objectives of the present disclosure may be used. In some examples, pure water, deionized water, or sterile water may be used. In other embodiments, an aqueous buffer may be used. For example, phosphate-buffered saline (PBS), Dulbecco's phosphate-buffered saline (DPBS), Hank's balanced salt solution (HBSS), or Earle's balanced salt solution (EBSS) may be used in some cases. Furthermore, in some embodiments, any alcohol not inconsistent with the technical objectives of the present disclosure may be used. In some embodiments, isopropyl alcohol, methanol, or ethanol may be used.

[0065] Further details regarding various methods, including "material deposition" methods (such as MJP) or "vat polymerization" methods (such as SLA), are provided below.

[0066] A. Material deposition method In the material deposition method, one or more layers of the build material described herein are selectively deposited on a substrate and cured, and curing of the build material may occur after the selective deposition of one, each, several, or all layers of the build material.

[0067] In some examples, a build material described herein (e.g., a composition described above in Section I) is selectively deposited in a fluid state onto a substrate, such as a build pad of a 3D printing system. Selective deposition may include, for example, depositing the build material according to preselected CAD parameters. For example, in some embodiments, a CAD file drawing corresponding to the desired 3D article to be printed is generated and sliced ​​into a sufficient number of horizontal slices. The build material is then selectively deposited layer-by-layer according to the horizontal slices of the CAD file drawing to print the desired 3D article. A "sufficient" number of horizontal slices is, for example, the number necessary to successfully print the desired 3D article for accurate and precise manufacturing.

[0068] Furthermore, in some embodiments, a preselected amount of the build material described herein is heated to an appropriate temperature and jetted through one or more print heads of a suitable inkjet printer to form a layer on a print pad within a print chamber. In some cases, each layer of build material is deposited according to preselected CAD or other preselected parameters based on a digital file, image, or model of the desired article. A print head suitable for depositing the build material is, in some embodiments, a piezoelectric print head. Additional print heads suitable for depositing the build materials and support materials described herein are commercially available from various inkjet printing device manufacturers. For example, print heads from Xerox, Hewlett-Packard, or Ricoh may be used in some instances.

[0069] Additionally, in some embodiments, the build materials described herein maintain a substantially fluid state after deposition. Alternatively, in other examples, the build material exhibits a phase change upon deposition and / or solidifies upon deposition. Furthermore, in some cases, the temperature of the printing environment can be controlled so that jetted droplets of the build material solidify upon contact with the receiving surface. In other embodiments, the jetted droplets of the build material do not solidify upon contact with the receiving surface but remain in a substantially fluid state. Furthermore, in some examples, after each layer is deposited and before the deposition of the next layer, the deposited material is planarized and cured with electromagnetic radiation (e.g., UV, visible, or infrared light). Optionally, multiple layers can be deposited before planarization and curing, or multiple layers can be deposited and cured, followed by deposition of one or more layers and then planarization without curing. Planarization compensates for the thickness of one or more layers by flattening the jetted material to remove excess material and form a uniformly smooth, exposed, or flat, upward-facing surface on the printer's support platform before the material is cured. In some embodiments, the planarization is performed using a wiper device, such as a roller, that counter-rotates in one or more print directions but not in one or more other print directions. In some cases, the wiper device comprises a roller and a wiper that removes excess material from the roller. Additionally, in some cases, the wiper device is heated. It should be noted that in some embodiments, it is desirable for the viscosity of the jetted build material described herein before curing to be such that it maintains its shape and does not experience excessive viscous drag from the planarization device.

[0070] Additionally, if a support material is used, it can be deposited in a manner consistent with that described above for the build material. The support material can be deposited according to preselected CAD parameters (or other parameters described herein), for example, so that the support material is adjacent to or contiguous with one or more layers of the build material. In some embodiments, the jetted droplets of support material solidify or freeze upon contact with the receiving surface. In some cases, the deposited support material is also subjected to planarization, hardening, or planarization and hardening. Any support material not inconsistent with the objectives of this disclosure can be used.

[0071] The layer-by-layer deposition of the build material and the support material can be repeated until the 3D article is formed. In some embodiments, the method of printing a 3D article further includes removing the support material from the build material. The support material can be removed by any method not inconsistent with the technical objectives of the present disclosure. In some cases, for example, removing the support material includes melting the support material. In some such embodiments, the support material is melted to a temperature below the melting point, softening point, heat distortion temperature (HDT), or T of the build material. g The support material has a melting point that is at least 20°C, at least 30°C, at least 40°C, at least 50°C, at least 70°C, or at least 100°C lower than the support material. In such cases, the support material comprises or is formed from a wax. Furthermore, in some preferred embodiments described herein, the support material is not removed by dissolving or dispersing the support material in water or by using the aqueous solutions described herein.

[0072] Curing of the build material may occur after selective deposition of one, each, multiple, or all layers of build material necessary to print the desired 3D article. In some embodiments, partial curing of the deposited build material occurs after selective deposition of one, each, multiple, or all layers of build material necessary to print the desired 3D article. For reference purposes herein, a "partially cured" build material refers to one that is capable of further curing. For example, a partially cured build material is up to about 30% polymerized or crosslinked, or up to about 50% polymerized or crosslinked. In some embodiments, a partially cured build material is up to about 60%, up to about 70%, up to about 80%, up to about 90%, or up to about 95% polymerized or crosslinked.

[0073] Partially curing the deposited build material can include irradiating the build material with an electromagnetic radiation source or photocuring the build material (including with curing radiation as described herein above). Any electromagnetic radiation source consistent with the objectives of this disclosure can be used, for example, an electromagnetic radiation source that emits UV, visible, or infrared light. For example, in some embodiments, the electromagnetic radiation source can emit light having a wavelength of about 300 nm to about 900 nm, such as a Xe arc lamp.

[0074] Further, in some embodiments, a post-cure is performed after the partial curing. For example, in some cases, the post-cure is performed after selectively depositing all layers of build material necessary to form the desired 3D article, after partially curing all layers of build material, or after both of the aforementioned steps are performed. Further, in some embodiments, the post-cure includes photo-curing, including with the aforementioned curing radiation having a peak wavelength λ. Again, any electromagnetic radiation source consistent with the objectives of the present disclosure can be used for the post-cure step described herein. For example, in some embodiments, the electromagnetic radiation source can be a light source having higher energy, lower energy, or the same energy as the electromagnetic radiation source used for the partial curing. If the electromagnetic radiation source used for the post-cure has higher energy (i.e., shorter wavelength) than that used for the partial curing, a Xe arc lamp can be used for the partial curing and a Hg lamp can be used for the post-cure.

[0075] Furthermore, after post-curing, in some cases, the deposited layer of build material is at least about 80% polymerized or crosslinked, or at least about 85% polymerized or crosslinked. In some embodiments, the deposited layer of build material is at least about 90%, at least about 95%, at least about 98%, or at least about 99% polymerized or crosslinked. In some examples, the deposited layer of build material is about 80-100%, about 80-99%, about 80-95%, about 85-100%, about 85-99%, about 85-95%, about 90-100%, or about 90-99% polymerized or crosslinked. The degree of polymerization or crosslinking can be determined using any protocol or method consistent with the technical objectives of the present disclosure, for example, by determining the percentage of monomer incorporated into the polymer network (e.g., based on the molecular weight of the polymer compared to the molecular weight of the monomer, or based on the total mass of the polymer compared to the theoretical maximum for the total mass of the polymer) or by determining the amount of unincorporated monomer. When multiple methods are used to determine the degree of polymerization or crosslinking, the results of the methods may be averaged to arrive at the percentages described herein. Furthermore, it should be understood that the degree of polymerization or crosslinking described herein is different from the "degree of polymerization," which is defined as the number of repeat units in a polymer molecule.

[0076] B. Vat Polymerization Method 3D articles can also be formed from the build materials described herein using vat polymerization methods, such as SLA and DLP. Accordingly, in some cases, methods of printing 3D articles described herein include maintaining the build materials described herein in a fluid state within a container and selectively applying energy (e.g., curing radiation having a peak wavelength λ) to the build material within the container to solidify at least a portion of the fluid layer of build material, thereby forming a solidified layer that defines a cross-section of the 3D article. Additionally, methods described herein can further include raising or lowering the solidified layer of build material to provide a new or second fluid layer of unsolidified build material on the surface of the fluid build material within the container, and then again selectively applying energy (e.g., curing radiation) to the build material within the container to solidify at least a portion of the new or second fluid layer of build material, thereby forming a second solidified layer 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 one another in the z-direction (or a build direction corresponding to the above-mentioned direction of raising or lowering) by application of energy to solidify the build material. Furthermore, in some examples, the electromagnetic radiation has an average wavelength of 300-900 nm, while in other embodiments, the electromagnetic radiation has an average wavelength of less than 300 nm. In some cases, the curing radiation is provided by a computer-controlled laser beam, DLP light source, or other light source. Furthermore, in some cases, raising or lowering the solidified layer of build material is accomplished using an elevator platform positioned within the container of fluid build material. The methods described herein can also include planarizing the new layer of fluid build material provided by raising or lowering the elevator platform. In some cases, such planarization can be accomplished by a wiper or roller.

[0077] It should further be understood that the foregoing process can be repeated as many times as desired to provide a 3D article. For example, in some cases, the process can be repeated "n" times, where n can be up to about 100,000, up to about 50,000, up to about 10,000, up to about 5,000, up to about 1,000, or up to about 500. Thus, in some embodiments, methods of printing 3D articles described herein include selectively applying energy (e.g., curing radiation at a peak wavelength λ) to build material in a container to solidify at least a portion of the nth fluid layer of build material, thereby forming an nth solidified layer that defines the nth cross-section of the 3D article; raising or lowering the nth solidified layer of build material to provide an (n+1)th layer of unsolidified build material on the surface of the fluid build material in the container; selectively applying energy to the (n+1)th layer of build material in the container to solidify at least a portion of the (n+1)th layer of build material, thereby forming an (n+1)th solidified layer that defines the (n+1)th cross-section of the 3D article; raising or lowering the (n+1)th solidified layer of build material to provide an (n+2)th layer of unsolidified build material on the surface of the fluid build material in the container; and continuing to repeat the foregoing steps to form the 3D article. It should further be understood that one or more steps of the methods described herein, such as selectively applying energy (e.g., curing radiation as described herein) to layers of build material, can be performed according to an image of the 3D article in a computer-readable format. General methods of 3D printing using stereolithography are further described in, among other places, U.S. Patent Nos. 5,904,889 and 6,558,606.

[0078] In vat polymerization methods such as those described above, the build material can be partially cured, as described in Section IIA above. For example, in some embodiments, selectively applying energy to the build material in the container to solidify at least a portion of the fluid layer of build material can include partially curing at least a portion of the fluid layer of build material. In other embodiments, partially curing at least a portion of the fluid layer of build material can occur after a first layer of build material is applied and solidified, before or after a second layer of build material is applied or solidified, or before or after one, more, or all subsequent layers of build material are applied or solidified.

[0079] Additionally, in some embodiments of the batch polymerization methods described herein, post-curing, as described above in Section IIA, can occur after partial curing or after the desired 3D article has been formed. The desired 3D article may be, for example, an article that corresponds to a design in a CAD file or other digital file, image, or model that corresponds to the desired 3D article.

[0080] III. Printed Articles In another aspect, printed 3D articles are described herein. In some embodiments, the printed 3D articles are formed from the compositions or build materials described herein and / or are formed using the additive manufacturing methods described herein. Any of the compositions described above in Section I can be used. For example, in some cases, the composition includes an acrylate component; a photoinitiator component; and a porogen component. Furthermore, in some such cases, the porogen component is water-soluble. Similarly, any of the methods described above in Section II can be used to form articles according to the present disclosure.

[0081] Articles printed according to the methods described herein can have high water permeability. In some embodiments, the articles can be -17 ~10 -14 m 2In some such instances, the article has a water permeability of 10 -16 ~10 -14 m 2 In another example, the article has a water permeability of 10 -16 ~10 -15 m 2 In yet another embodiment, the article has a water permeability of 10 -15 ~10 -14 m 2 It has a water permeability of .

[0082] To evaluate the water permeability of printed articles, a Franz cell is used. Non-limiting examples of a Franz cell are shown in Figures 1A and 1B. Non-limiting examples of experimental setups for measuring the water permeability of articles using a Franz cell are shown in Figures 2 and 3.

[0083] Referring to Figures 1A, 1B, 2, and 3, the Franz cell (10) is maintained at 37°C by an incubator (not shown). The printed article (200) replaces the normal membrane in the Franz cell. The tested article (200) typically has a thickness of 0.46 mm to 0.63 mm, or 0.5 mm to 1 mm. However, in some embodiments, materials as thin as 0.01 mm and as thick as 1.3 mm can be tested. Materials thicker than 1.3 mm can also be evaluated. The Franz cell (10) includes a donor chamber (110) and a receptor chamber (111) and a sampling arm or port (116). Additionally, flat flanges (112) associated with the donor chamber (110) and receptor chamber (111) can form a joint with the printed article (200) positioned between the flanges (112), as shown in Figure 1B. A clamp (120) can be used to clamp the donor chamber (110) and receptor chamber (111) together via flange (112). Clamp (120) is shown in Figures 2 and 3, but is not shown in Figures 1A or 1B for clarity. Figure 1A shows the Franz cell (10) in an exploded view. Figure 1B shows the Franz cell (10) in an assembled or unexploded view.

[0084] The experimental setup also includes an air pressure pump (not shown) to apply pressure to the donor chamber (110) of the Franz cell (10). The pressure is applied in the direction indicated by the arrow (100) in Figures 1 and 2. The air pressure pump is typically set to 30 mmHg or 60 mmHg. Water is supplied to the donor chamber (110) from a reservoir (300) or similar. A camera (320) is used to monitor the movement and flow of water through the article (200) and into the receptor chamber (111) over time. The change in water level in the donor chamber (110) is also measured. The experiment is continued for 2 to 24 hours, or until all of the water applied to the donor chamber (110) has migrated through the article (200) and into the receptor chamber (111). The flow rate of water transported through the membrane (printed article (200)) is determined by measuring the distance traveled by water in the receptor chamber (111) over time, for example, based on the movement of the water level (118) in the sampling port (116), as indicated by the ruler (240). The pressure of the setup is also monitored, such as by using a pressure sensor (310) connected to the Franz cell (10) using a hose and / or connector (312). Based on the measurements obtained, the permeability (k) can be calculated using Darcy's law using the following equation:

number

[0085] Articles printed by the methods described herein can find use in a variety of fields, including the medical field. The article can be, for example, a medical implant. [Example]

[0086] Some specific embodiments of the build materials (or inks or polymerizable liquids), methods, and articles are further illustrated in the following non-limiting examples.

[0087] Table 2 provides formulations of build materials prepared according to some embodiments described herein, specifically Examples 1-3. In Table 2, "Ex." means "Example," and the amounts listed for a given Example composition are weight percents based on the total weight of the Example composition. It should be understood that all components of a given Example composition total 100 weight percent. "PI" means "photoinitiator," and "PS" means "photosensitizer." Table 3 lists the components of Examples 1-3. Table 4 lists water permeability information for articles printed from such compositions, measured as described above. Additionally, in Table 3, "QY" refers to quinoline yellow, "PGME" refers to propylene glycol methyl ether, and "TGME" refers to tripropylene glycol methyl ether. Additionally, in Table 3, "EPA" refers to ethoxylated o-phenylphenol acrylate, and "TDD" refers to tricyclodecane dimethanol diacrylate. [Table 2] [Table 3] [Table 4]

[0088] Table 5 provides additional formulations of build materials according to some embodiments described herein, specifically Examples 4-6. Table 6 provides the components of Examples 4-6. The same abbreviations as shown in Tables 2 and 3 also apply to Tables 5 and 6. [Table 5] [Table 6]

[0089] Some additional non-limiting exemplary embodiments are as follows:

[0090] Embodiment 1. A building material comprising: acrylate component; a photoinitiator component; and porogen component; Including, The porogen component is water soluble, A build material wherein the porogen component is present in the build material in an amount of 55 to 75 weight percent based on the total weight of the build material.

[0091] Embodiment 2. The build material of embodiment 1, wherein the porogen component is miscible in water at 20°C.

[0092] Embodiment 3. The build material of embodiment 1, wherein the porogen component has a solubility of 20% to 100% in water at 20°C.

[0093] Embodiment 4. The build material of embodiment 1, wherein the porogen component has a solubility in water of at least 150 g / L at 20°C.

[0094] Embodiment 5. The build material of any one of embodiments 1-4, wherein the porogen component has a surface tension of 25-30 dynes / cm at 25° C. as measured according to ASTM D1331-20.

[0095] Embodiment 6: The porogen component is 14 to 17 (J / cm 3 ) 1 / 2 Hansen solubility parameter δ d , 2 to 8 (J / cm 3 ) 1 / 2 Hansen solubility parameter δ p , and 10-15 (J / cm 3 ) 1 / 2 Hansen solubility parameter δ h 2. The building material of embodiment 1, having

[0096] Embodiment 7. The build material of any one of embodiments 1-6, wherein the porogen component comprises a glycol ether.

[0097] Embodiment 8. The build material of embodiment 7, wherein the glycol ether comprises propylene glycol methyl ether or tripropylene glycol methyl ether.

[0098] Embodiment 9. The build material of any one of embodiments 1-8, wherein the acrylate component comprises a urethane acrylate.

[0099] Embodiment 10. The building material of any one of embodiments 1-9, wherein the urethane acrylate comprises a polyether urethane acrylate.

[0100] Embodiment 11. The build material of embodiment 9, wherein the urethane acrylate comprises a polyurethane acrylate.

[0101] Embodiment 12. The build material of any one of embodiments 1 to 11, wherein the acrylate component is present in the build material in an amount of 20 to 40% by weight, based on the total weight of the build material.

[0102] Embodiment 13. The build material of any one of embodiments 1 to 12, wherein the photoinitiator component is present in the build material in an amount of 0.5 to 2% by weight, based on the total weight of the build material.

[0103] Embodiment 14. The build material of any one of embodiments 1-13, wherein the photoinitiator component comprises benzoylphosphine oxide.

[0104] Embodiment 15. The building material of any one of embodiments 1 to 14, wherein the building material further comprises a colorant.

[0105] Embodiment 16. A method of forming a three-dimensional article by additive manufacturing, comprising: Providing a building material according to any one of embodiments 1 to 15; and Printing and curing the build material to form a printed three-dimensional article. A method comprising:

[0106] Embodiment 17. The method of embodiment 16, wherein the build material is provided in a layer-by-layer process.

[0107] Embodiment 18. The method of embodiment 16 or embodiment 17, further comprising washing the printed three-dimensional article with an aqueous solution.

[0108] Embodiment 19. A printed three-dimensional article formed from the build material of any one of embodiments 1-15.

[0109] Embodiment 20.10 -17 ~10 -14 m 2 20. The article of claim 19, having a water permeability of

[0110] Embodiment 21.10 -16 ~10 -14 m 2 21. The article of claim 20, having a water permeability of

[0111] Embodiment 22. The article of embodiment 19, 20, or 21, which is a medical implant.

[0112] All patents mentioned herein are incorporated by reference in their entirety. Various embodiments of the present invention have been described to achieve various objectives of the present invention. It should be recognized that these embodiments are merely illustrative of the principles of the present invention. Numerous modifications and adaptations will be readily apparent to those skilled in the art without departing from the spirit and scope of the present invention.

Claims

1. A building material comprising: acrylate component; a photoinitiator component; and porogen component; Including, the porogen component is water-soluble; The porogen component is present in the build material in an amount of 55 to 75 weight percent based on the total weight of the build material. A molding material characterized by:

2. The build material of claim 1 , wherein the porogen component is miscible in water at 20° C.

3. 2. The build material of claim 1, wherein the porogen component has a solubility of 20% to 100% in water at 20°C.

4. The build material of claim 1 , wherein the porogen component has a solubility in water of at least 150 g / L at 20° C.

5. 10. The build material of claim 1, wherein the porogen component has a surface tension of 25-30 dynes / cm at 25°C as measured according to ASTM D1331-20.

6. The porogen component has a viscosity of 14 to 17 (J / cm ３ ) １／２ Hansen solubility parameter δ ｄ , 2 to 8 (J / cm ３ ) １／２ Hansen solubility parameter δ ｐ , and 10 to 15 (J / cm ３ ) １／２ Hansen solubility parameter δ ｈ 10. The building material of claim 1, wherein

7. The build material of claim 1 , wherein the porogen component comprises a glycol ether.

8. 8. The build material of claim 7, wherein the glycol ether comprises propylene glycol methyl ether or tripropylene glycol methyl ether.

9. The build material of claim 1 , wherein the acrylate component comprises a urethane acrylate.

10. 10. The build material of claim 9, wherein the urethane acrylate comprises a polyether urethane acrylate.

11. 10. The build material of claim 9, wherein the urethane acrylate comprises a polyurethane acrylate.

12. 2. The build material of claim 1, wherein the acrylate component is present in the build material in an amount of 20 to 40% by weight, based on the total weight of the build material.

13. 2. The build material of claim 1, wherein the photoinitiator component is present in the build material in an amount of 0.5 to 2% by weight, based on the total weight of the build material.

14. The build material of claim 1 , wherein the photoinitiator component comprises benzoylphosphine oxide.

15. The build material of claim 1 , further comprising a colorant.

16. 1. A method of forming a three-dimensional article by additive manufacturing, comprising: Providing the build material of claim 1; and printing and curing said build material to form a printed three-dimensional article. A method comprising:

17. 17. The method of claim 16, wherein the build material is applied in a layer-by-layer process.

18. 17. The method of claim 16, further comprising washing the printed three-dimensional article with an aqueous solution.

19. 10. A printed three-dimensional article formed from the build material of claim 1.

20. 10 －１７ ~10 －１４ m ２ 20. The article of claim 19, having a water permeability of

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