WO2025057020A1 - Photopolymerizable compositions including urea/acrylamide functional component, articles and methods - Google Patents

Abstract

The present disclosure provides a photopolymerizable composition comprising at least one (meth)acrylate reactive diluent and a polymerization reaction product of components comprising a urea functional component or an acrylamide functional component. The present disclosure also provides an orthodontic article and methods of making the orthodontic article. The method includes obtaining a photopolymerizable composition and selectively curing the photopolymerizable composition to form an orthodontic article. Further, methods are provided, including receiving, by a manufacturing device having one or more processors, a digital object comprising data specifying an orthodontic article; and generating, with the manufacturing device by an additive manufacturing process, the orthodontic article based on the digital object. A dental restorative tool or mold comprising a polymerized reaction product of a photopolymerizable composition is also provided.

Description

PHOTOPOLYMERIZABLE COMPOSITIONS INCLUDING UREA/ACRYLAMIDE FUNCTIONAL COMPONENT, ARTICLES AND METHODS

TECHNICAL FIELD

[0001] The present disclosure broadly relates to polymerizable compositions, articles, and methods of making the articles, such as additive manufacturing methods.

BACKGROUND

[0002] The recent development of 3D printing, also known as additive manufacturing, layered manufacturing, or rapid prototyping, is advantageous in the production of complex objects without the use of any mold or special machining. In particular, 3D photopolymerization based techniques, such as stereolithography, provides fabrication of multifunctional material-based systems with controllable mechanical, optical, physical, and chemical properties. The ability to achieve high resolution and flexibility of stereolithography technique makes it more suitable for 3D printing over other vat polymerization processes (over other vat polymerization techniques, such as digital light processing, and continuous liquid interface production).

[0003] Stereolithography utilizes the method of photo-curing or photo-crosslinking a liquid resin in the presence of a photoinitiator. Stereolithography 3D printing can be carried out by top-down or bottom-up process, is a layer-by layer addition and is a recurring two-step technique. The first step involves curing a layer of curable liquid composition corresponding to the desired cross-sectional area of the 3D printing article with the suitable radiation and the second step includes covering the first cured layer with a second new layer of the curable composition, and repeating the steps until the desired green body of the 3D article with definite shape and size is achieved. The process further involves post processing the green body of the 3D article to undergo complete curing and to strengthen the article.

[0004] Apart from photo-based 3D printing techniques, nozzle-based techniques, such as inkjet printing can also be employed for printing various three dimensional articles. Inkjet printing utilizes layer by layer deposition of ink/curable photopolymerizable liquid jetted through a print head followed by curing. The inkjet printers may optionally be used in conjunction with a support material or a bonding agent. In some cases, inkjet printers may use the ink or the build materials which are solid at ambient temperatures and becomes liquid at increased jetting temperatures. In a few other cases, the build material is liquid at ambient temperatures.

SUMMARY

[0005] Successful 3D printing ultimately lies in the use of compatible polymerizable/printable compositions which can exhibit desired hardness with least elongation and high glass transition temperature. Available polymeric resins are too brittle for an oral appliance, such as an aligner or a dental restorative tool or a mold. Oral appliances made out of existing polymeric resins could break easily and hence becomes harmful when used during oral treatment. Further, their poor tensile properties may cause tissue puncture, may abrade, or can crumble causing them to be ingested. Additionally, it is also important that the non-cured polymerizable composition have appropriate viscosity, and a suitable curing rate to aid 3D printing. Therefore there is an unmet need for curable liquid resin compositions that are tailored and well suited for the creation of resilient articles using 3D printing (e.g., additive manufacturing) method. Preferably, the curable liquid resin compositions should have low viscosity, an optimal curing rate, and excellent mechanical properties in the final cured article. In contrast, the compositions for inkjet printing processes need to be of a much lower viscosity to be able to be jetted through nozzles, which is not the case for most vat polymerization resins.

[0006] In a first aspect, a photopolymerizable composition is provided. The photopolymerizable composition includes a) 30-60 wt.% of at least one (meth)acrylate reactive diluent; b) a photoinitiator; and c) 30-60 wt.% of a polymerization reaction product of components including a urea functional component or an acrylamide functional component. The photopolymerizable composition exhibits a dynamic viscosity of less than 5000 centipoises (cP), when measured by a cone and plate rheometer at a temperature of 20 degrees Celsius and at a shear rate of 1 1/s.

[0008] In a second aspect, an orthodontic article is provided. The orthodontic article includes a polymerized reaction product of a photopolymerizable composition. The photopolymerizable composition includes 45-60 wt.% of at least one (meth)acrylate reactive diluent, based on a total weight of the photopolymerizable composition; a photoinitiator; and 30-50 wt.% of a first polymerization reaction product of components, based on the total weight of the photopolymerizable composition. The first polymerization reaction product includes a first polyether polyamine; and an ethylenically-unsaturated isocyanate functional monomer. The photopolymerizable composition optionally includes up to 10 wt.% of a crosslinker having a glass transition temperature (T_g) of 50°C or greater; and optionally up to 12 wt.% of a second polymerization reaction product of components, based on the total weight of the photopolymerizable composition. The second polymerization reaction product includes a second polyether polyamine; and an ethylenically-unsaturated isocyanate functional monomer. The photopolymerizable composition includes the provisos that: A) when the first polymerization reaction product of components is present in an amount of 40-50 wt.%, the composition contains no more than 5 wt.% of the second polymerization reaction product of components; and B) when the first polymerization reaction product of components is present in an amount of 30 wt.% to less than 40 wt.%, the composition includes at least one of the following: i) 55-60 wt.% of the (meth)acrylate reactive diluent; ii) 5-12 wt.% of the second polymerization reaction product of components; or iii) 5-10 wt.% of the crosslinker; or iv) 1-10 wt.% of methacrylic acid. The polymerized reaction product has a T_g of 50°C or greater.

[0009] In a third aspect, an orthodontic article is provided. The orthodontic article includes a polymerized reaction product of a photopolymerizable composition. The photopolymerizable composition includes 30-50 wt.% of a (meth)acrylate reactive diluent; a photoinitiator; and 40-60 wt.% of a polymerization reaction product. The polymerization reaction product includes a polymeric diol; and an azlactone. Often the polymerized reaction product has a T_g of 50 °C or greater.

[0010] In a fourth aspect, a method of making an orthodontic article is provided. The method includes (a) providing the photopolymerizable composition (e.g., the photopolymerizable composition according to the first aspect) and (b) selectively curing the photopolymerizable composition to form a layer of an orthodontic article. The method also includes (c) repeating steps (a) and (b) to form multiple layers and create the orthodontic article having a three-dimensional structure. The method optionally includes curing unpolymerized photopolymerizable composition remaining after step (c). The method further optionally includes removing at least a portion of the unpolymerized photopolymerizable composition remaining after step (c).

[0011] In a fifth aspect, a method is provided. The method includes receiving, by a manufacturing device having one or more processors, a digital object comprising data specifying a plurality of layers of an orthodontic article; and generating, with the manufacturing device by an additive manufacturing process, the orthodontic article based on the digital object, the orthodontic article comprising a reaction product of a photopolymerizable composition (e.g., the photopolymerizable composition according to the first aspect).

[0012] In a sixth aspect, a dental restorative tool or mold is provided. The dental restorative tool or mold includes a polymerized reaction product of a photopolymerizable composition according to the first aspect.

[0013] In a seventh aspect, a system is provided. The system includes a) a display that displays a 3D model of an orthodontic article; and b) one or more processors that, in response to the 3D model selected by a user, cause a 3D printer to create a physical object of an orthodontic article. The orthodontic article includes a reaction product of a photopolymerizable composition (e.g., the photopolymerizable composition according to the first aspect).

[0014] Clear tray aligners (e.g., orthodontic alignment trays) and tensile bars made according to at least certain embodiments of this disclosure were found to show low brittleness, good resistance to water, and good toughness.

[0015] The above summary of the present disclosure is not intended to describe each disclosed embodiment or every implementation of the present disclosure. The description that follows more particularly exemplifies illustrative embodiments. In several places throughout the application, guidance is provided through lists of examples, which examples can be used in various combinations. In each instance, the recited list serves only as a representative group and should not be interpreted as an exclusive list.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIG. 1 is a flowchart of a process for building an article using photopolymerizable compositions disclosed herein.

[0017] FIG. 2 is a generalized schematic of a stereolithography apparatus.

[0018] FIG. 3 is an isometric view of a printed clear tray aligner, according to one embodiment of the present disclosure.

[0019] FIG. 4 is a flowchart of a process for manufacturing a printed orthodontic appliance according to the present disclosure.

[0020] FIG. 5 is a generalized schematic of an apparatus in which radiation is directed through a container.

[0021] FIG. 6 is a block diagram of a generalized system 600 for additive manufacturing of an article.

[0022] FIG. 7 is a block diagram of a generalized manufacturing process for an article.

[0023] FIG. 8 is a high-level flow chart of an exemplary article manufacturing process.

[0024] FIG. 9 is a high-level flow chart of an exemplary article additive manufacturing process.

[0025] FIG. 10 is a schematic front view of an exemplary computing device 1000.

[0026] While the above-identified figures set forth several embodiments of the disclosure other embodiments are also contemplated, as noted in the description. The figures are not necessarily drawn to scale. In all cases, this disclosure presents the invention by way of representation and not limitation. It should be understood that numerous other modifications and embodiments can be devised by those skilled in the art, which fall within the scope and spirit of the principles of the invention.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

[0027] Those skilled in the art will be aware that the present disclosure is subject to variations and modifications other than those specifically described. It is to be understood that the present disclosure includes all such variations and modifications. The disclosure also includes all such steps, features, compositions, and compounds referred to or indicated in this specification, individually or collectively, and any and all combinations of any or more of such steps or features.

Definitions

[0028] For convenience, before further description of the present disclosure, certain terms employed in the specification, and examples are delineated here. These definitions should be read in light of the remainder of the disclosure and understood as by a person of skill in the art. The terms used herein have the meanings recognized and known to those of skill in the art, however, for convenience and completeness, particular terms and their meanings are set forth below.

[0029] As used herein, the term “at least one” is used to mean one or more and thus includes individual components as well as mixture s/combinations.

[0030] As used herein, the term “aliphatic group” means a saturated or unsaturated linear, branched, or cyclic hydrocarbon group. The term “cycloaliphatic” refers to cyclic hydrocarbon group. This term is used to encompass alkyl, alkenyl, and alkynyl groups, for example.

[0031] As used herein, the term “alkyl” means a linear or branched, cyclic or acyclic, saturated monovalent hydrocarbon having from one to thirty-two carbon atoms, e.g., methyl, ethyl, 1-propyl, 2 -propyl, pentyl, and the like.

[0032] As used herein, the term “alkenyl” refers to a monovalent linear or branched unsaturated aliphatic group with one or more carbon-carbon double bonds, e.g., vinyl. Unless otherwise indicated, the alkenyl groups typically contain from two to twenty carbon atoms.

[0033] As used herein, the term “alkynyl” refers to a monovalent linear or branched unsaturated aliphatic group with one or more carbon-carbon triple bonds. Unless otherwise indicated, the alkynyl groups typically contain from two to twenty carbon atoms.

[0034] As used herein, the term “arylene” or “aryl” refers to a carbocyclic and aromatic. The group has one to five rings that are connected, fused, or combinations thereof. The other rings can be aromatic, non-aromatic, or combinations thereof. In some embodiments, the arylene group has up to 5 rings, up to 4 rings, up to 3 rings, up to 2 rings, or one aromatic ring. For example, the arylene group can be phenylene.

[0035] As used herein, the term “cycloalkyl” refers to a carbocyclic group which is completely saturated. The group has one to five rings that are connected, fused, or combinations thereof. The other rings can be aromatic, non-aromatic, or combinations thereof. In some embodiments, the cycloalkyl group has up to 5 rings, up to 4 rings, up to 3 rings, up to 2 rings, or one saturated carbocyclic ring.

[0036] As used herein, the term “heterocyclic” refers to a group that is carbocyclic having at least one hetero atom. The group has one to five rings that are connected, fused, or combinations thereof. The other rings can be aromatic, non-aromatic, or combinations thereof. In some embodiments, the heterocyclic group has up to 5 rings, up to 4 rings, up to 3 rings, up to 2 rings, or one heterocyclyl ring. In some embodiments, the heterocyclic group has at least one, at least two or at least three hetero atoms. The heteroatoms include other atoms apart from carbon and hydrogen, which is preferably nitrogen, sulphur, oxygen, phosphorus and so on. [0037] As used herein, the term “essentially free” in the context of a composition being essentially free of a component, refers to a composition containing less than 1% by weight (wt.%), 0.5 wt.% or less, 0.25 wt.% or less, 0.1 wt.% or less, 0.05 wt.% or less, 0.001 wt.% or less, or 0.0001 wt.% or less of the component, based on the total weight of the composition.

[0038] As used herein, the term “glass transition temperature” (T_g), of a polymer refers to the temperature at which the glass transition occurs, i.e., transition of an uncrosslinked polymer from a glassy state to a rubbery state. T_g can be measured using Differential Scanning Calorimetry (DSC), such as at a heating rate of 10°C per minute in a nitrogen stream. T_g of a monomer also refers to the T_g of a homopolymer of that monomer. The homopolymer must have sufficiently high molecular weight such that the T_g reaches a limiting value, as it is generally appreciated that a T_g of a homopolymer will increase with increasing molecular weight to a limiting value. The homopolymer is also understood to be substantially free of moisture, residual monomer, solvents, and other contaminants that may affect the T_g. A suitable DSC method and mode of analysis is as described in Matsumoto, A. et. al., J. Polym. Sci. A., Polym. Chem. 1993, 31, 2531-2539. In an alternate method, T_g of a crosslinked polymer can be obtained by measuring tan delta of the crosslinked polymer, determined from dynamic mechanical analysis and the T_g is defined as the peak of tan delta.

[0039] As used herein, the term “Young’s modulus” refers to mechanical property of a polymer that is a measure of the tensile strength or stiffness of the polymer, in the presence of an external applied force. Young’s modulus also referred to as elastic modulus or tensile modulus indicates the ability of the material to stretch or bend. Higher young’s modulus indicates the polymer is much stiffer, less brittle and does not undergo any deformation.

[0040] As used herein, the term “tensile strain at break” refers to the measure of the maximum strain a material can withstand before breaking while being stretched. The tensile strain is the measure of increase in length that material will achieve before breaking. Higher tensile strain at break means the polymer is capable of withstanding large amounts of strain before breaking.

[0041] As used herein, the term “tensile stress at break” or “ultimate tensile strength” refers to the maximum stress a polymer can withstand while being stretched before breaking. The tensile stress is a measure of the polymer’s stiffness and higher tensile stress at break means the polymer is capable of withstanding large amounts of stress before breaking.

[0042] As used herein, the term “dynamic viscosity” refers to the measure of resistance of a polymer to flow when an external force is applied. The term “dynamic viscosity” as used herein is the viscosity of the moving fluid, i.e, the non-cured photopolymerizable composition. The dynamic viscosity of non-cured photopolymerizable composition of the present disclosure is measured by a cone and plate rheometer at a temperature of 20°C and at a shear rate of 1 1/s. [0043] As used herein, the term “hardenable” refers to a material that can be cured or solidified, e.g., by heating to remove solvent, heating to cause polymerization, chemical crosslinking, radiation- induced polymerization or crosslinking, or the like.

[0044] As used herein, the term “curing” refers to a process of complete hardening or partial hardening of a composition facilitated by any mechanism, such as heat, light, radiation, e-beam, microwave, chemical reaction, or combinations thereof.

[0045] As used herein, the term “cured” refers to a material or composition that has been hardened or partially hardened (e.g., polymerized or crosslinked) by curing.

[0046] As used herein, “integral” refers to being made at the same time or being incapable of being separated without damaging one or more of the (integral) parts.

[0047] As used herein, the term “(meth)acrylate” refers to acrylate, methacrylate, or combinations thereof, “(meth)acrylic” is a shorthand reference to acrylic, methacrylic, or combinations thereof, and “(meth)acryl” is a shorthand reference to acryl and methacryl groups. “Acryl” refers to derivatives of acrylic acid, such as acrylates, methacrylates, acrylamides, and methacrylamides. “(meth)acryl” refers to a monomer or oligomer having at least one acryl or methacryl groups, and linked by an aliphatic segment if containing two or more groups.

[0048] As used herein, the term “photopolymerizable composition” refers to hardenable composition capable of undergoing polymerization upon photoinitiation. Typically, prior to polymerization (e.g., hardening), the photopolymerizable composition has a viscosity profile consistent with the requirements and parameters of one or more 3D printing systems. In some embodiments, for instance, hardening comprises irradiating with actinic radiation having sufficient energy to initiate a polymerization or cross-linking reaction. It is noted that the polymerizable components of a photopolymerizable composition will add up to a total of 100 wt.%. Accordingly, additives that do not participate in the polymerization, like fillers, are not included in determining the wt.% of various components in the photopolymerizable compositions.

[0049] As used herein, “polymerized reaction product” refers to a product obtained by polymerization reaction of one or more components in the presence of suitable initiator and optionally a crosslinker. In some embodiments, the polymerized reaction product includes the reaction product of photopolymerizable composition as disclosed herein.

[0050] As used herein, “resin” contains all polymerizable components (monomers, oligomers and/or polymers) being present in a hardenable composition. The resin may contain only one polymerizable component compound or a mixture of different polymerizable compounds.

[0051] As used herein, “occlusal” means in a direction toward the outer tips of the patient's teeth; “facial” means in a direction toward the patient's lips or cheeks; and “lingual” means in a direction toward the patient's tongue. [0052] The words “preferred” and “preferably” refer to embodiments of the disclosure that may afford certain benefits, under certain circumstances. However, other embodiments may also be preferred, under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, and is not intended to exclude other embodiments from the scope of the disclosure.

[0053] As used herein, the terms, such as “a”, “an”, and “the” are not intended to refer to only a singular entity, but include the general class of which a specific example may be used for illustration. The terms “a”, “an”, and “the” are used interchangeably with the term “at least one”. The phrases “at least one of and “comprises” at least one of followed by a list refers to any one of the items in the list and any combination of two or more items in the list.

[0054] As used herein, the term “or” is generally employed in its usual sense including “and/or” unless the content clearly dictates otherwise.

[0055] As used herein, the term “and/or” means one or all of the listed elements or a combination of any two or more of the listed elements.

[0056] As used herein, the terms “comprise” and “comprising” are used in the inclusive, open sense, meaning that additional elements may be included. It is not intended to be construed as “consists of only”. Throughout this specification, unless the context requires otherwise the word “comprise”, and variations, such as “comprises” and “comprising”, will be understood to imply the inclusion of a stated element or step or group of element or steps but not the exclusion of any other element or steps.

[0057] The terms “including” is used to mean “including but not limited to”, “including” and “including but not limited to” are used interchangeably.

[0058] Also herein, all numbers are assumed to be modified by the term “about” and preferably by the term “exactly.” As used herein in connection with a measured quantity, the term “about” refers to that variation in the measured quantity as would be expected by the skilled artisan making the measurement and exercising a level of care commensurate with the objective of the measurement and the precision of the measuring equipment used. Also herein, the recitations of numerical ranges by endpoints include all numbers subsumed within that range as well as the endpoints (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, 5, etc.).

[0059] As used herein as a modifier to a property or attribute, the term “generally”, unless otherwise specifically defined, means that the property or attribute would be readily recognizable by a person of ordinary skill but without requiring absolute precision or a perfect match (e.g., within +/- 20 % for quantifiable properties). The term “substantially”, unless otherwise specifically defined, means to a high degree of approximation (e.g., within +/- 10% for quantifiable properties) but again without requiring absolute precision or a perfect match. Terms, such as same, equal, uniform, constant, strictly, and the like, are understood to be within the usual tolerances or measuring error applicable to the particular circumstance rather than requiring absolute precision or a perfect match.

[0060] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the disclosure, the preferred methods and materials are now described. All publications mentioned herein are incorporated herein by reference.

[0061] The present disclosure is not to be limited in scope by the specific embodiments described herein, which are intended for the purposes of exemplification only. Functionally equivalent products, compositions, and methods are clearly within the scope of the disclosure, as described herein.

[0062] In a first aspect, the present disclosure provides a photopolymerizable composition. The photopolymerizable composition includes a) 30-60 wt.% of at least one (meth)acrylate reactive diluent; b) a photoinitiator; and c) 30-60 wt.% of a polymerization reaction product of components including a urea functional component or an acrylamide functional component. The photopolymerizable composition exhibits a dynamic viscosity of less than 5000 centipoises (cP), when measured by a cone and plate rheometer at a temperature of 20 degrees Celsius and at a shear rate of 1 1/s.

[0063] The photopolymerizable composition includes a) 45-60 wt.% of the at least one (meth)acrylate reactive diluent, based on a total weight of the photopolymerizable composition; b) 30-50 wt.% of a first polymerization reaction product of components, based on the total weight of the photopolymerizable composition, the components comprising: a first polyether poly amine; and an ethylenically-unsaturated isocyanate functional monomer, c) optionally up to 10 wt.% of a crosslinker having a glass transition temperature (T_g) of 50°C or greater; and d) optionally up to 12 wt.% of a second polymerization reaction product of components, based on the total weight of the photopolymerizable composition, the components comprising a second polyether polyamine; and an ethylenically-unsaturated isocyanate functional monomer. The photopolymerizable composition includes the first polymerization reaction product of components in an amount of 40-50 wt.%, and the composition contains no more than 5 wt.% of the second polymerization reaction product of components. The photopolymerizable composition includes the first polymerization reaction product of components in an amount of 30 wt.% to less than 40 wt.%, then the composition includes at least one of 55-60 wt.% of the (meth) acrylate reactive diluent, 5-12 wt.% of the second polymerization reaction product of components, 5-10 wt.% of the crosslinker, or 1-10 wt.% of methacrylic acid. [0064] The photopolymerizable composition includes 30-50 wt.% of the (meth) acrylate reactive diluent; and 40-60 wt.% of the polymerization reaction product of components, the components comprising: a polymeric diol; and an azlactone.

(Meth)acrylate reactive diluent

[0065] The photopolymerizable compositions of the present disclosure include at least one (meth)acrylate reactive diluent. A “reactive diluent,” for reference purposes herein, is a component that contains at least one free radically reactive group that can co-react with another component (e.g., a urea functional component or an acrylamide functional component capable of undergoing polymerization). In an embodiment, the photopolymerizable composition comprises a (meth)acrylate reactive diluent having a glass transition temperature (T_g), i.e., whose cured homopolymer has a T_g of 30°C or greater. In few embodiments, a monofunctional (meth)acrylate monomer is present whose cured homopolymer has a T_g of 40 °C or greater, 50°C or greater, 60°C or greater, 70°C or greater, 80 °C or greater, 90 °C or greater, 100 °C or greater, 110 °C or greater, 120 °C or greater, 125 °C or greater, 130 °C or greater, 135 °C or greater, 140 °C or greater, 145 °C or greater, 150 °C or greater, 155 °C or greater, 160 °C or greater, 165 °C or greater, 170 °C or greater, 175 °C or greater, 180 °C or greater, 185 °C or greater, 190 °C or greater, or even 195 °C or greater. In select embodiments, a monofunctional (meth)acrylate monomer is present whose cured homopolymer has a T_g of 150 °C or greater, 170 °C or greater, or 180 °C or greater. The T_g of the homopolymer of the monofunctional (meth) acrylate monomer is typically no greater than about 260 °C. In some embodiments, the T_g of the homopolymer of the monofunctional (meth)acrylate monomer is no greater than 255 °C, 250 °C, 245 °C, 240 °C, 235 °C, 230 °C, 225 °C, 220 °C, 215 °C, 210 °C, 205 °C or 200 °C.

[0066] The inclusion of one or more monofunctional (meth)acrylate monomers whose cured homopolymer has a T_g of 50 °C or greater in a photopolymerizable composition contributes to drop in viscosity of the composition and also increase the relaxation modulus of a polymerization reaction product of the composition as measured after soaking in deionized water. Often, the T_g of a homopolymer of a monomer can be found in the literature, such as in Table A below. Table A includes the reported T_g of the homopolymer of a number of monofunctional (meth)acrylate monomers and the literature source of the reported T_g. Table A

[0067] In some embodiments, the (meth) acrylate reactive diluent is present in an amount of 30 parts or more by weight per 100 parts of the total photopolymerizable composition, 31 parts or more, 35 parts or more, 40 parts or more, 45 parts or more, 50 parts or more, or 55 parts or more; and 60 parts or less, 59 parts or less, 58 parts or less, 57 parts or less, 56 parts or less, or 55 parts or less, by weight per 100 parts of the total photopolymerizable composition.

[0068] In some embodiments, the (meth)acrylate reactive diluent having a T_g of at least 30°C are present in an amount of at least 15, 20, 25, 30, 35, 40, 45, 50, or 55 wt.%, based on the total weight of the organic components of the composition.

[0069] In some embodiments of the present disclosure, the cured material will be in contact with an aqueous environment. In those cases, it is advantageous to utilize materials that have a low affinity for water. The affinity for water of certain (meth)acrylate monomers can be estimated by the calculation of a partition coefficient (P) between water and an immiscible solvent, such as octanol. This can serve as a quantitative descriptor of hydrophilicity or lipophilicity. The octanol/water partition coefficient can be calculated by software programs, such as ACD ChemSketch, (Advanced Chemistry Development, Inc., Toronto, Canada) using the log of octanol/water partition coefficient (log P) module.

[0070] In embodiments of the present invention, the calculated log P value is greater than 1, 1.5, 2, 2.5, 3, 3.5, or 4. The calculated log P value is typically no greater than 12.5. In some embodiments, the calculated log P value is no greater than 12, 11.5, 11, 10.5, 10, 9.5, 9, 8.5, 8, 7.5, 7, 6.5, 6, or 5.5. Moreover, in some embodiments, the photopolymerizable compositions exclude the presence of a significant amount of hydrophilic (meth)acrylate monomers by being essentially free of any (meth)acrylate reactive diluent having a log P value of less than 3, less than 2, or less than 1.

[0071] In some embodiments, the photopolymerizable compositions contain hydrophilic (meth)acrylate monomers, oligomers, or polymers (e.g., hydrophilic urethane (meth)acrylate) having a log P value of less than 3, less than 2, or less than 1, in an amount of less than 30% by weight, based on the total weight of the photopolymerizable composition, such as 29% or less, 28%, 27%, 26%, 25%, 24%, 23%, 22%, 21%, 20%, 19%, 18%, 17%, 16%, 15%, 14%, 13%, 12%, or 11% or less of hydrophilic components; and 1% by weight or more, 2%, 3%, 4%, 5%, 7%, 9%, or 10% or more hydrophilic components, for example, 1% to 29% by weight, based on the total weight of the photopolymerizable composition. In some embodiments, the combination of a hydrophilic component and a monomer of (meth)acrylate reactive diluent whose cured homopolymer has a T_g of 150 °C or greater can impart advantageous properties to an article, for instance, 20% by weight or more of the high T_g monomer, 22%, 25%, 27%, 30%, 32%, 35%, 37%, 40%, 42%, 45%, 47%, or 50% by weight or more of a monofunctional (meth)acrylate monomer whose cured homopolymer has a T_g of 150 °C may be included when 1% to 29% by weight of a hydrophilic component is present, each based on the total weight of the photopolymerizable composition.

[0072] In some embodiments, the photopolymerizable compositions containing little to no low molecular weight difunctional component (e.g., a dimethacrylate), inclusion of an insufficient amount of a relatively high T_g monomer (e.g., over 125 °C, 140 °C, 150 °C, or over 160 °C), may negatively impact the ability of a polymerization reaction product of the photopolymerization composition to yield (e.g., having increased brittleness).

[0073] In some embodiments, the (meth) acrylate reactive diluent includes for instance without limitation, at least one of isobornyl methacrylate, isobornyl acrylate, methyl methacrylate, tertiobutyl cyclohexyl methacrylate, 3,3,5 trimethylcyclohexyl methacrylate, tricyclodecanedimethanol diacrylate or combinations thereof. In an embodiment, the (meth) acrylate reactive diluent is isobornyl methacrylate. Suitable (meth)acrylate reactive diluents for use in the components include for instance and without limitation, those commercially available from Sartomer, Warrington, Pennsylvania, under the trade series: SR423A, SR218, SR421, and SR506.

Urea functional component

[0074] In an embodiment, the photopolymerizable composition comprises 30 to 60 wt.% of a polymerization reaction product of components comprising a urea functional component. In some embodiments, the urea functional component is a reaction product of components comprising an amine and an isocyanate. In another embodiment, the urea functional component is obtained as a reaction product of a polyether polyamine and an ethylenically-unsaturated isocyanate functional monomer. In other embodiments, the urea functional component is obtained as a first polymerization reaction product of components comprising a first polyether polyamine and an ethylenically- unsaturated isocyanate functional monomer. In other embodiments, the urea functional component is obtained as a second polymerization reaction product of components comprising a second polyether polyamine and an ethylenically-unsaturated isocyanate functional monomer.

[0075] In some embodiments, the photopolymerizable composition comprises about 30 to 60 wt.% of a polymerization reaction product comprising a urea functional component. In various embodiments, the photopolymerizable composition comprises about 30 to 50 wt.% of a polymerization reaction product comprising a urea functional component. In other embodiments, the photopolymerizable composition comprises about 40 to 50 wt.% of a polymerization reaction product comprising a urea functional component. In some embodiments, the photopolymerizable composition comprises about 30 to 40 wt.% of a polymerization reaction product comprising a urea functional component.

[0076] In other embodiments, the photopolymerizable composition comprises about 30 to 50 wt.% of a first polymerization reaction product of components comprising a urea functional component. In other embodiments, the photopolymerizable composition optionally comprises up to 12 wt.% of a second polymerization reaction product of components comprising a urea functional component. [0077] In some embodiments, the polymerization reaction product comprises urea functional component in an amount of 30 parts or more by weight per 100 parts of the total photopolymerizable composition, 31 parts or more, 35 parts or more, 40 parts or more, 45 parts or more, 50 parts or more, or 55 parts or more; and 60 parts or less, 59 parts or less, 58 parts or less, 57 parts or less, 56 parts or less, or 55 parts or less, by weight per 100 parts of the total photopolymerizable composition. [0078] In some embodiments, the polymerization reaction product comprising urea functional component is a first polymerization reaction product of components and is present in an amount of 30 parts or more by weight per 100 parts of the total photopolymerizable composition, 31 parts or more, 35 parts or more, 40 parts or more, 45 parts or more, 49 parts or more; and 50 parts or less, 49 parts or less, 48 parts or less, 47 parts or less, 46 parts or less, or 45 parts or less, by weight per 100 parts of the total photopolymerizable composition.

[0079] In some embodiments, the polymerization reaction product comprising urea functional component is a second polymerization reaction product of components and is present in an amount of 5 parts or more by weight per 100 parts of the total photopolymerizable composition, 6 parts or more, 7 parts or more, 8 parts or more, 9 parts or more; and 12 parts or less, 11 parts or less, 10 parts or less, 9 parts or less, 8 parts or less, 7 parts or less, 6 parts or less, by weight per 100 parts of the total photopolymerizable composition.

[0080] In some embodiments, the photopolymerizable composition comprises the first polymerization reaction product of components in an amount of 40-50 wt.% and the composition contains no more than 5 wt.% of the second polymerization reaction product of components. In other embodiments, the photopolymerizable composition comprises the first polymerization reaction product of components in 30 wt.% to less than 40 wt.%, and the composition may include 5-12 wt.% of the second polymerization reaction product of components.

Polyether polyamine

Polyether triamine

[0081] In some embodiments, the polyether polyamine is a polyether triamine. In some embodiments, the polyether triamine has a structure of Formula II,

Formula II wherein, the subscript ‘n’ is typically at least 1, 2, 3, 4, 5, or more. The subscript ‘n’ is no greater than 10, 9, 8, 7 or 6. The subscript ‘x’ is typically at least 1, 2, 3, 4, 5, or more; and the subscript ‘x’ is no greater than 84, 80, 75, 70, 65, or 60. The subscript ‘y’ is typically at least 1, 2, 3, 4, 5, or more; and the subscript ‘y’ is no greater than 84, 80, 75, 70, 65, or 60. The subscript ‘z’ is typically at least 1, 2, 3, 4, 5, or more; and the subscript ‘z’ is no greater than 84, 80, 75, 70, 65, or 60.

[0082] In some embodiments, the poly ether triamine has a weight average molecular weight (M„) of 300 to 6,500 grams per mole (g/mol), wherein M„ is determined by gel permeation chromatography. In some embodiments, the polyether triamine is present having a M_n of 300 grams per mole (g/mol) or greater, 350 grams per mole (g/mol) or greater, 400 grams per mole (g/mol) or greater, 450 grams per mole (g/mol) or greater, 500 g/mol or greater, 550 g/mol or greater, 600 g/mol or greater, 650 g/mol or greater, 700 g/mol or greater, 750 g/mol or greater, 800 g/mol or greater, 850 g/mol or greater, 900 g/mol or greater, 950 g/mol or greater, 1,000 g/mol or greater, 2,000 g/mol or greater, or 3,000 g/mol or greater; and 6,500 g/mol or less, 6,000 g/mol or less, 5,500 g/mol or less, 5,000 g/mol or less, 4,500 g/mol or less, 4,000 g/mol or less, 3,900 g/mol or less, 3,800 g/mol or less, 3,700 g/mol or less, 3,600 g/mol or less, 3,500 g/mol or less, 3,400 g/mol or less, 3,300 g/mol or less, 3,200 g/mol or less, 3,100 g/mol or less, 3,000 g/mol or less, 2,900 g/mol or less, 2,800 g/mol or less, or 2,700 g/mol or less. Stated another way, the polyether triamine may have a M„ of 300 g/mol to 6,500 g/mol, 800 g/mol to 6,500 g/mol, 1,000 g/mol to 5,500 g/mol, 1,500 g/mol to 5,000 g/mol, 1,800 g/mol to 5,000 g/mol, 450 g/mol to 4,500 g/mol, 800 g/mol to 4,500 g/mol, 1,000 g/mol to 4,500 g/mol, 1,500 g/mol to 4,500 g/mol, or 1,800 g/mol to 4,500 g/mol.

[0083] Suitable polyether triamines for use in the components include for instance and without limitation, those commercially available from Huntsman, The Woodlands, Texas, under the trade designation of “Jeffamine”, e.g., Jeffamine T-3000 and Jeffamine T-5000. Also from BASF corporation, under the trade name of Baxxodur, specifically Baxxodur EC 310 from BASF corporation, Florham Park, New Jersey.

Polyether diamine

[0084] In some embodiments, the poly ether poly amine is a poly ether diamine. In some embodiments, the polyether diamine has a structure of Formula I,

Formula I wherein, the subscript ‘x’ is typically at least 4, 5, 6, 7, 8, or more. The subscript ‘x’ is no greater than 90, 89, 88, 87 or 86.

[0085] In some embodiments, the poly ether diamine has a weight average molecular weight (M„) of 100 to 4,000 grams per mole (g/mol), wherein M„ is determined by gel permeation chromatography. In some embodiments, the polyether diamine is present having a M„ of 100 grams per mole (g/mol) or greater, 150 grams per mole (g/mol) or greater, 200 grams per mole (g/mol) or greater, 250 grams per mole (g/mol) or greater, 300 g/mol or greater, 350 g/mol or greater, 400 g/mol or greater, 550 g/mol or greater, 600 g/mol or greater, 650 g/mol or greater, 700 g/mol or greater, 750 g/mol or greater, 800 g/mol or greater, 850 g/mol or greater, 900 g/mol or greater, 950 g/mol or greater, 1,000 g/mol or greater, 2,000 g/mol or greater, or 3,000 g/mol or greater; and 5,000 g/mol or less, 4,500 g/mol or less, 4,000 g/mol or less, 3,500 g/mol or less, 3,000 g/mol or less, 2,900 g/mol or less, 2,800 g/mol or less, 2,700 g/mol or less, 2,600 g/mol or less, 2,500 g/mol or less, 2,400 g/mol or less, 2,300 g/mol or less, 2,200 g/mol or less, 2,100 g/mol or less, 2,000 g/mol or less, 1,900 g/mol or less, 1,800 g/mol or less, or 1,700 g/mol or less. Stated another way, the polyether diamine may have a M„ of 100 g/mol to 5,000 g/mol, 200 g/mol to 4,000 g/mol, 500 g/mol to 5,000 g/mol, 1,500 g/mol to 4,000 g/mol, 1,800 g/mol to 4,000 g/mol, 250 g/mol to 3,500 g/mol, 800 g/mol to 3,500 g/mol, 1,000 g/mol to 3500 g/mol, 1,500 g/mol to 3,500 g/mol, or 1,800 g/mol to 3,500 g/mol.

[0086] Suitable polyether diamines for use in the components include for instance and without limitation, those commercially available from Huntsman, The Woodlands, Texas, under the trade designation of “Jeffamine”, e.g., Jeffamine D-400, Jeffamine D-2000, and Jeffamine D-4000 and also from BASF corporation under the trade name Baxxodur, obtained as Baxxodur EC 301 from BASF, Wyandotte, Michigan. Ethylenically-unsaturated isocyanate functional monomer

[0087] In some embodiments, ethylenically unsaturated isocyanate functional monomers include monomers and oligomers of esters having ethylenic saturation and one more acid groups. The acid functionality typically includes an oxygen containing acid group of carbon, sulfur, or phosphorous, such as carboxylic acid functionality, phosphoric acid functionality, phosphonic acid functionality, phosphinic acid functionality, sulfonic acid functionality, sulfinic acid functionality or combinations thereof. In some embodiments, the ethylenically unsaturated group is a (meth)acryl group, such as (meth)acrylate. Alternatively, such as in the case of acrylic acid, methacrylic acid, itaconic acid, fumaric acid, crotonic acid, citraconic acid, maleic acid, oleic acid; the acid has an unsaturated carbon bond (i.e. alkenyl group). In some embodiments, the ethylenically unsaturated component with acid functionality has a low affinity for water, such as in the case of oleic acid.

[0088] In some embodiments, the ethylenically unsaturated isocyanate functional monomer includes esters of ethylenically unsaturated (meth)acrylic acids. In some embodiments, the ethylenically unsaturated isocyanate functional monomer include isocyanatoalkyl esters of ethylenically unsaturated (meth)acrylic acids. Examples of isocyanatoalkyl esters include but are not limited to 2-isocyanatoethyl methacrylate and 2-isocyanatoethyl acrylate. In some embodiments, the ethylenically unsaturated isocyanate functional monomer includes acryloyl isocyanates. Examples of acryloyl isocyanates include but are not limited to methacryloyl isocyanate.

[0089] Suitable ethylenically unsaturated isocyanate functional monomers for use in the components include for instance and without limitation, those commercially available from Resonac Corporation, Tokyo, Japan, such as, 2-isocyanatoethyl methacrylate (IEM), and 2-isocyanatoethyl acrylate (IE A).

Acrylamide functional component

[0090] In an embodiment, the photopolymerizable composition comprises 30 to 60 wt.% of a polymerization reaction product of components comprising an acrylamide functional component. In some embodiments, the acrylamide functional component is a reaction product of components comprising a diol and a lactone. In some embodiments, the acrylamide functional component is obtained as a reaction product of a polymeric diol and an azlactone. In other embodiments, acrylamide functional component is obtained as a polymerization reaction product of a polymeric diol and an azlactone comprising 2-vinyl-4,4-dimethylazlactone. In other embodiments, the polymeric diol comprises a polyester diol, a polycarbonate diol, a polyether diol, a polyolefin diol, or combinations thereof. In other embodiments, the acrylamide functional component is obtained as a polymerization reaction product of a polycarbonate diol and an azlactone. In other embodiments, the acrylamide functional component is obtained as a polymerization reaction product of a polyester diol and an azlactone. In other embodiments, the acrylamide functional component is obtained as a polymerization reaction product of a poly ether diol and an azlactone. In other embodiments, the acrylamide functional component is obtained as a polymerization reaction product of a polyolefin diol and an azlactone.

[0091] In some embodiments, the photopolymerizable composition comprises about 40 to 60 wt.% of a polymerization reaction product of components comprising an acrylamide functional component. In other embodiments, the photopolymerizable composition comprises about 42 to 57 wt.% of a polymerization reaction product of components comprising an acrylamide functional component.

[0092] In some embodiments, the acrylamide functional component is present in an amount of 40 parts or more by weight per 100 parts of the total photopolymerizable composition, 41 parts or more, 45 parts or more, 50 parts or more, 55 parts or more, and 60 parts or less, 59 parts or less, 58 parts or less, 57 parts or less, 56 parts or less, or 55 parts or less, by weight per 100 parts of the total photopolymerizable composition.

Polycarbonate diol

[0093] In some embodiments, the polycarbonate diol is of Formula III:

H(O-Ri-O-C(=O))_m-O-R₂-OH

Formula III wherein each of Ri in each (O-Ri-O-C(=O)) repeat unit, and R₂, are independently an aliphatic, cycloaliphatic, or aliphatic/cycloaliphatic alkylene group and an average number of carbon atoms in a combination of all the Ri and R₂ groups is 4 to 10, and m is (an integer of) 2 to 23. Stated another way, while some repeat units of Ri and/or R₂, may have a carbon number of less than 4 (e.g., 2 or 3), enough of the repeat units have a sufficiently high carbon number that when the carbon numbers of all the repeat units of Ri and R₂ in the polycarbonate diol of Formula III are averaged, that average falls within the range of 4 to 10, or any of 4 to 6, 4 to 7, 4 to 8, 4 to 9, 5 to 7, 5 to 8, 5 to 9, 5 to 10, 6 to 8, 6 to 9, 6 to 10, 7 to 9, 7 to 10, or 8 to 10. In contrast, a polycarbonate diol having a molecular weight of about 1,500 g/mol made with CO₂ and propylene oxide available as “CONVERGE POLYOL 212-20” from Aramco, (Dhahran, Saudi Arabia), has an average number of carbon atoms in a combination of all the Ri and R₂ groups is just 3. In select embodiments, at least one of Ri or R₂ is -CH₂CH₂CH(CH3)CH₂CH₂-, -(CH₂)e-, or -(CH₂)4-, and preferably a combination of - CH₂CH₂CH(CH₃)CH₂CH₂-, and -(CH₂)₆-

[0094] In some embodiments, either the polycarbonate diol has a number average molecular weight (M_n) of greater than 1 ,000 grams per mole (g/mol) or a weighted average of all polycarbonate diols present in the components has a M_n of greater than 1 ,000 g/mol, wherein M_n is determined by OH value. Stated a different way, when the components contain a single polycarbonate diol of Formula III, the polycarbonate diol has a M_n higher than 1 ,000 g/mol. [0095] When the components contain two or more polycarbonate diols (e.g., one or more being of Formula III), the M_n of at least one of the polycarbonate diols may be 1,000 g/mol or less with the proviso that a weighted average of all the M_n values of the two or more polycarbonate diols is higher than 1,000 g/mol. For instance, components containing two polycarbonate diols could include a molar ratio of a first polycarbonate diol having a M_n of about 500 g/mol of 1 to a second polycarbonate diol having a M_n of about 1,500 g/mol of 2, resulting in a weighted average M_n of 1,167 g/mol. In certain embodiments, a polycarbonate diol (or a weighted average of all the polycarbonate diols present in the components) has number average molecular weight of 1,500 g/mol or higher. In certain embodiments, a polycarbonate diol (or a weighted average of all the polycarbonate diols present in the components) has number average molecular weight of 2,000 g/mol or higher.

[0096] In some embodiments, one or more polycarbonate diols are present having a M_n of 450 grams per mole (g/mol) or greater, 500 g/mol or greater, 550 g/mol or greater, 600 g/mol or greater, 650 g/mol or greater, 700 g/mol or greater, 750 g/mol or greater, 800 g/mol or greater, 850 g/mol or greater, 900 g/mol or greater, 950 g/mol or greater, or 1,000 g/mol or greater; and 3,200 g/mol or less, 3,100 g/mol or less, 3,000 g/mol or less, 2,900 g/mol or less, 2,800 g/mol or less, 2,700 g/mol or less, 2,600 g/mol or less, 2,500 g/mol or less, 2,400 g/mol or less, 2,300 g/mol or less, 2,200 g/mol or less, 2,100 g/mol or less, 2,000 g/mol or less, 1,900 g/mol or less, 1,800 g/mol or less, or 1,700 g/mol or less. Stated another way, the polycarbonate diol may have a M_n of 450 g/mol to 3,200 g/mol, 800 g/mol to 3,200 g/mol, 1,000 g/mol to 3,200 g/mol, 1,500 g/mol to 3,200 g/mol, 1,800 g/mol to 3,200 g/mol, 450 g/mol to 2,200 g/mol, 800 g/mol to 2,200 g/mol, 1,000 g/mol to 2,200 g/mol, 1,500 g/mol to 2,200 g/mol, or 1,800 g/mol to 2,200 g/mol. Inclusion of a polycarbonate diol having a M_n of greater than 3,200 g/mol, on the other hand, may negatively impact the stiffness of a polymerization reaction product of the polymerization composition, by increasing the elastomeric character of the polymerization reaction product.

[0097] In select embodiments, the photopolymerizable composition is essentially free of any diols that have a M_n lower than the one or more polycarbonate diols present in the components. In embodiments of photopolymerizable compositions containing a relatively low T_g monomer (e.g., under 90 °C, 80 °C, or under 60 °C), inclusion of a polycarbonate diol having a M_n of greater than 1,500 g/mol may negatively impact the ability of a polymerization reaction product of the polymerization composition to yield (e.g., having increased brittleness). Similarly, in embodiments of photopolymerizable compositions containing a polycarbonate diol having a M_n of greater than 1,500 g/mol, inclusion of an insufficient amount of a relatively high T_g monomer (e.g., over 90 °C, 100 °C, 125 °C, or over 150 °C), may negatively impact the ability of a polymerization reaction product of the photopolymerizable composition to yield (e.g., having increased brittleness). [0098] Suitable polycarbonate diols for use in the components include for instance and without limitation, those commercially available from Kuraray Co. Ltd. (Tokyo, JP) under the trade designation “KURARAY POLYOL”, e.g., specifically, each of the KURARAY POLYOL C series: C-590, C-1090, C-2050, C-2090, and C-3090; from Covestro LLC (Pittsburgh, PA) under the trade designation “DESMOPHEN”, e.g., specifically, each of the DESMOPHEN C series: C- 2100, C- 2200, and C XP-2613.

Polyester Diol

[0099] In some embodiments, the polyester diol has Formula IV, as follows:

H[O-R₅-O-C(=O)-R₆-C(=O)]₁ -O-R₅-OH

Formula IV wherein, Rs and R(> are independently straight or branched chain or cycle -containing alkylene, groups, that optionally include heteroatoms, such as oxygen. Rs and Re independently comprise 2 to 40 carbon atoms. The subscript “i” is typically at least 2, 3, 4, 5, 6, or 7. The subscript “i” is typically no greater than 50, 45, 40, 35, 30, 25, 20, or 15. In some embodiments, the Rs and Re are alkylene. [0100] Representative polyester diols include for example neopentyl glycol adipate diol, butane diol adipate diol, 3-methyl-l,5-pentanediol adipate diol, and 3-methyl-l,5-pentanediol sebecate diol, and dimer acid based polyols in which the dimer acid is derived for example from dimerization of two 18 carbon diacids, such as linoleic acid.

[0101] In some embodiments, such as the diols just described, the polyester diol comprises a single Rs group (e.g. neopentyl or 3 -methyl- 1,5 -pentyl) and a single Re group (e.g. adipate).

[0102] In other embodiments, the polyester diol can be prepared from more than one diol and more than one acid. In this embodiment, the diol can contain two or more different Rs groups and two or more different Rs groups, such as in the case of ethylene glycol-hexane diol/adipate-azelate copolyester diol.

[0103] In other embodiments, the polyester diol has Formula V, as follows: H[-O-R₈-C(=O)]j-O-R7-O-[C(=O)- R₈-O]_k-H

Formula V wherein, R? and Rs are independently straight or branched chain or cycle -containing alkylene groups that optionally include heteroatoms, such as oxygen, the alkylene groups independently comprise 2 to 40 carbon atoms. The subscripts “j” and “k” are typically independently at least 4, 5 or 6. The subscripts “j” and “k” are typically independently no greater than 25, 20, or 15.

[0104] One representative polyester diol of this type is polycaprolactone diol, such as available from Perstorp. In this embodiment, Rs is a C alkylene group and R? is the residue of an alcohol, such as ethylene glycol, butylene glycol, diethylene glycol, and the like. [0105] In some embodiments, at least one of R5 or R<> of Formula IV and at least one of R7 and Rs of Formula V is a straight or branched chain or cycle -containing alkylene group independently comprising at least 4, 5, or 6 carbon atoms.

[0106] In some embodiments, each of the R5 or Re of Formula IV are alkylene groups independently comprising at least 4, 5, or 6 carbon atoms. In some embodiments, each of the R7 and Rs groups of Formula V are alkylene groups independently comprising at least 4, 5, or 6 carbon atoms.

[0107] The values of i, j, and k are chosen such that the molecular weight (M_n) of the diol is at least 500, 600, 700, 800, 900, or 1000 g/mole. In some embodiments, the molecular weight (M_n) of the diol is at least 1100, 1200, 1300, 1400, 1500 g/mole. In some embodiments, the molecular weight (M_n) of the diol is at least 1600, 1700, 1800, 1900, or 2000 g/mole. In some embodiments, the molecular weight (M_n) of the diol is no greater than 10,000; 9,000; 8,000; 7,000; 6,000; 5000; 4000; or 3000 g/mole. The values of i, j, and k can vary widely due to the range of carbons for the R5, R<>. R7, and Rs groups.

Polyether diol

[0108] In some embodiments, the polyether diol is typically of Formula VI as follows: H[O-R₉]h-OH Formula VI wherein each R₉ is independently selected from straight or branched chain or cycle -containing alkylene groups of 2 to 6 carbon atoms, more preferably 3-4 carbon atoms, and h is typically is at least 7, but no higher than 80. The value of h is chosen such that the molecular weight (M_n) of the diol is at least 500, 600, 700, 800, 900, or 1000 g/mole. In some embodiments, the molecular weight (M_n) of the diol is at least 1100, 1200, 1300, 1400, 1500 g/mole. In some embodiments, the molecular weight (M_n) of the diol is at least 1600, 1700, 1800, 1900, or 2000 g/mole. In some embodiments, the molecular weight (M_n) of the diol is no greater than 10,000; 9,000; 8,000; 7,000; 6,000; 5000; 4000; or 3000 g/mole. When the molecular weight is too low the elongation can be insufficient (i.e., less than 15-20 %).

Polyolefin Diol

[0109] In some embodiments, the polyolefin diol is typically of Formula VII as follows:

H0[Rw]i-0H Formula VII wherein each Rio is independently selected from straight or branched chain or cycle -containing alkenyl groups of 2 to 12 carbon atoms, more preferably 3-4 carbon atoms, and 1 is typically is at least 7, but no higher than 80. The value of 1 is chosen such that the molecular weight (M_n) of the diol is at least 500, 600, 700, 800, 900, or 1000 g/mole. In some embodiments, the molecular weight (M_n) of the diol is at least 1100, 1200, 1300, 1400, 1500 g/mole. In some embodiments, the molecular weight (M_n) of the diol is at least 1600, 1700, 1800, 1900, or 2000 g/mole. In some embodiments, the molecular weight (M_n) of the diol is no greater than 10,000; 9,000; 8,000; 7,000; 6,000; 5000; 4000; or 3000 g/mole.

Azlactone

[0110] In some embodiments, an azlactone is typically of Formula VIII as follows:

Formula VIII wherein R_a and Rb are each independently selected from H, a nitrile group, an alkyl group, an alkenyl group, a cycloalkyl group, a heterocyclic group, and an aryl group, or R_a and R² taken together with the carbon to which they are attached form a carbocyclic ring; R_c and Rd are each independently selected from an alkyl group, a cycloalkyl group, an aryl group, or R_c and Rd taken together with the carbon to which they are attached form a carbocyclic ring; Q is a linking group selected from a covalent bond, an aryl group, (-CH2-)_o,-CO-O-(CH2)_o-, -CO-O-(CH2CH2O)_o-, -CO-NR^e-(CH2)_o,- CO-S-(CH2)_O-, wherein o is 1 to 12, and R^e is H, an alkyl group, a cycloalkyl group, a heterocyclic group or an aryl group; and n is 0 or 1.

[0111] Examples of azlactone include, but are not limited to, vinyl alkyl azlactones, such as 2-vinyl- 4,4-dimethylazlactone (also called 2-vinyl-4,4-dimethyl-2-oxazolin-5-one), 2-(4-vinylphenyl)-4,4- dimethylazlactone, 2-isopropenyl-4,4-dimethylazlactone, 2-vinyl-4-ethyl-4-methyl-2-oxazolin-5- one, and 2-vinyl-4,4-dimethyl-l,3-oxazin-6-one.

Crosslinker

[0112] The photopolymerizable composition of the present disclosure optionally comprises a crosslinker. A crosslinker may be used to increase the cohesive strength and the tensile strength of the polymerizable material. Suitable crosslinking additives for use herein may have multiple (meth)acrylate groups which may be alkoxylated. In some embodiments, crosslinker is selected from multifunctional methacrylate compounds with a glass transition temperature (T_g) of 50° C or greater and substituents capable of forming high crosslink densities can provide a matrix with improved gas and water vapor barrier properties. Suitable examples include, but are not limited to, those available under the trade designations SR 348 (ethoxylated (2) bisphenol A di(meth) acrylate), SR540 (ethoxylated (4) bisphenol A di(meth) acrylate), SR444 (pentaerythritol triacrylate), SR351 (trimethacrylolpropane triacrylate), SR368 (tris(2-hydroxy ethyl)isocyanurate triacrylate), SR833s(tricyclodecane dimethanol diacrylate) and SR239 (1,6-hexane diol di(meth)acrylate) from Sartomer USA, LLC, Exton, Pennsylvania. [0113] In some embodiments, crosslinkers include photocrosslinkers (e.g., UV photocrosslinkers). These photocrosslinkers can be copolymerizable with the various monomers used to form the elastomeric material (e.g., copolymerizable benzophenones) or can be added after polymerization. Suitable photocrosslinkers added after polymerization include, for example, multifunctional benzophenones, triazines (such as XL-330, which is 2,4,-bis(trichloromethyl)-6-(4- methoxyphenyl) -triazine from 3M Company, Saint Paul, MN), acetophenones, and the like.

[0114] In some embodiments, thermal crosslinkers may be used, optionally in combination with suitable accelerants and retardants. Suitable thermal crosslinkers for use herein include, but are not limited to, isocyanates, more particularly trimerized isocyanates and/or sterically hindered isocyanates that are free of blocking agents, or else epoxide compounds, such as epoxideamine crosslinker systems. Advantageous crosslinker systems and methods are described e.g., in the descriptions of DE202009013255 U1 , EP 2 305 389 A , EP 2 414 143 A , EP 2 192 148 A , EP 2 186 869 , EP 0 752 435 A , EP 1 802 722 A , EP 1 791 921 A , EP 1 791 922 A , EP 1 978 069 A , and DE 102008 059 050 A . Suitable accelerants and retardant systems for use herein are described e.g., in the description of US-A1-2011/0281964 . Suitable thermal crosslinkers for use herein include epoxycyclohexyl derivatives, in particular epoxycyclohexyl carboxylate derivatives, with particular preference to (3,4-epoxycyclohexane)methyl 3,4-epoxycyclohexylcarboxylate, commercially available from Cytec Industries Inc. under tradename UVACURE 1500.

[0115] In some embodiments, the crosslinker for use herein is activated/activable with actinic radiation, more preferably with e-beam irradiation.

[9116] In certain embodiments, the crosslinker comprises a polymerized reaction product of a polyamine and an azlactone. The crosslinker may be obtained as a polymerized reaction product of a polyether polyamine and an azlactone. The polyether polyamine may be selected from polyether diamine or polyether triamine according to embodiments herein. The azlactone include but not limited to 2-vinyl-4,4-dimethylazlactone, 2-(4-vinylphenyl)-4,4-dimethylazlactone, 2-isopropenyl- 4,4-dimethylazlactone, 2-vinyl-4-ethyl-4-methyl-2-oxazolin -5-one, and 2-vinyl-4,4-dimethyl- 1,3- oxazin-6-one. In some embodiments, the crosslinker may be obtained as a polymerized reaction product of a polyether diamine and 2-vinyl-4,4 dimethylazlactone.

[0117] The crosslinker if present, may be used for example in amounts of up to 10 wt.%, based on the total weight of the photopolymerizable composition. In some embodiments, the crosslinker may be used in amounts up to 10 wt.%, up to 5 wt.%, up to 3 wt.%, or up to 1 wt.%, based on the weight of the photopolymerizable composition. In some embodiments, the crosslinker may be used in an amount of 5 to 10 wt.%, based on the weight of the photopolymerizable composition.

Catalyst [0118] The photopolymerizable composition of the present disclosure optionally comprises a catalyst. Typically, catalyst is included in an amount of 0.001 wt.% to 5 wt.%, based on the total weight of the polymerizable components.

[0119] Examples of suitable catalysts include for instance and without limitation, 1,8-diazabicyclo- [5.4.0]-undec-7-ene (DBU), dioctyl dilaurate (DOTDL), stannous octoate, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin mercaptide, dibutyltin thiocarboxylate, dibutyltin dimaleate, dioctyltin mercaptide, dioctyltin thiocarboxylate, lead 2-ethylhexanoate, tetra-alkyl titanates, such as tetrabutyl titanate (TBT), triethylamine, N, N- dimethylcyclohexylamine, N-methylmorpholine, N-ethylmorpholine, N, N-dimethyl-p-toluidine, beta-(dimethylamino) propionitrile, N- methylpyrrolidone, N, N-dicyclohexylmethylamine, dimethylaminoethanol, dimethylaminoethoxyethanol, triethylenediamine, N, N, N'-trimethyl aminoethyl ethanol amine, N, N, N', N'- tetramethylethylenediamine, N, N, N', N'-tetramethyl-l,3- diamine, N, N, N', N'-tetramethyl-l,6- hexanediol-diamine, bis(N, N-dimethylaminoethyl) ether, N'-cyclohexyl-N, N-dimethyl- formamidine, N, N'-dimethylpiperazine, trimethyl piperazine, bis(aminopropyl) piperazine, N-(N, N'-dimethylaminoethyl) morpholine, bis(morpholinoethyl) ether, 1, 2-dimethyl imidazole, N- methylimidazole, 1,4-diamidines, diazabicyclo-[2.2.2]-octane (DABCO), 1,4- diazabicyclo [3.3.0]- oct-4-ene (DBN), 1,8- diazabicyclo-[4.3.0]-non-5-ene (DBN), and phenol salts, salts, such as octyl acid salts, N, N, N', N"-pentamethyldiethylenetriamine, N, N, N', N" -pentamethyl dipropylenetriamine, tetramethylguanidine, N-cyclohexyl-N', N', N", N" -tetramethyl guanidine, N - methyl -N'-(2- dimethyl amino ethyl) piperazine, 1,3,5-tris (N, N- dimethyl -propyl)-hexahydro- 1,3, 5 -triazine.

[0120] In one embodiment, the catalyst comprises zinc, an amine, tin, zirconium, or bismuth. The catalyst can comprise tin, such as dibutyltin diacrylate. Preferably, the catalyst is free of tin, as tin catalysts may not be desirable to include in orthodontic articles that will be in contact with a patient’s mouth.

[0121] The catalyst may comprise an organometallic zinc complex that is free of 2 -ethylhexyl carboxylate and 2 -ethylhexanoic acid, such as the zinc catalyst commercially available from King Industries, Inc. (Norwalk, CT) under the trade designation K-KAT XK-672, and/or other zinc catalysts available from King Industries, such as K-KAT XK-661, and K-KAT XK-635. Another suitable catalyst is bismuth neodecanoate, for instance commercially available from Sigma-Aldrich (St. Louis, MO), as well as bismuth catalysts available from King Industries under the trade designations K-KAT XK-651 and K-KAT 348. Available aluminum based catalysts include K- KAT 5218 from King Industries. Further, zirconium based catalysts include K-KAT 4205 and K- KAT 6212 available from King Industries. [0122] In some embodiments, a catalyst is present in an amount of 0.001 wt.% or more, 0.002 wt.% or more, 0.003 wt.% or more, 0.005 wt.% or more, 0.01 wt.% or more, 0.1 wt.% or more, 0.2 wt.% or more, 0.5 wt.% or more, 1 wt.% or more, 2.0 wt.% or more, 3.0 wt.% or more, or 4.0 wt.% or more; and 5 wt.% or less, 4.8 wt.% or less, 4.6 wt.% or less, 4.4 wt.% or less, 4.2 wt.% or less, 4.0 wt.% or less, 3.8 wt.% or less, 3.6 wt.% or less, 3.4 wt.% or less, 3.2 wt.% or less, 3.0 wt.% or less, 2.8 wt.% or less, 2.6 wt.% or less, 2.4 wt.% or less, 2.2 wt.% or less, 2.0 wt.% or less, 1.8 wt.% or less, or 1.6 wt.% or less. Stated another way, the catalyst may be present in an amount of about 0.001-5% by weight, 0.002-1% by weight, or 0.003-0.5% by weight, based on the total weight of the photopolymerizable composition.

Photoinitiator

[0123] Photopolymerizable compositions of the present disclosure typically include at least one photoinitiator.

[0124] Suitable exemplary photoinitiators are those available under the trade designations IRGACURE and DAROCUR from BASF (Ludwigshafen, Germany) and include 1- hydroxycyclohexyl phenyl ketone (IRGACURE 184), 2,2-dimethoxy-l,2-diphenylethan-l-one (IRGACURE 651), bis(2,4,6 trimethylbenzoyl)phenylphosphineoxide (IRGACURE 819), l-[4-(2- hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-l -propane- 1 -one (IRGACURE 2959), 2-benzyl-2- dimethylamino-l-(4-morpholinophenyl)butanone (IRGACURE 369), 2-methyl-l-[4- (methylthio)phenyl]-2- morpholinopropan- 1 -one (IRGACURE 907), Oligo[2-hydroxy-2-methyl-l- [4-(l -methyl vinyl)phenyl]propanone] ESACURE ONE (Lamberti S.p.A., Gallarate, Italy), 2- hydroxy-2-methyl-l -phenyl propan-l-one (DAROCUR 1173), 2,4,6- trimethylbenzoyldiphenylphosphine oxide (IRGACURE TPO), and 2,4,6-trimethylbenzoylphenyl phosphinate (IRGACURE TPO-L).

[0125] Other exemplary photoinitiators are those available under the trade designations OMNIRAD from IGM Resins (Waalwijk, The Netherlands) and include 1 -hydroxy cyclohexyl phenyl ketone (OMNIRAD 184), 2,2-dimethoxy-l,2-diphenylethan-l-one (OMNIRAD 651), bis(2,4,6 trimethylbenzoyl)phenylphosphineoxide (OMNIRAD 819), l-[4-(2- hy droxy ethoxy )phenyl] -2- hydroxy-2-methyl-l -propane- 1 -one (OMNIRAD 2959), 2-benzyl-2- dimethylamino-l-(4- morpholinophenyl)butanone (OMNIRAD 369), 2-dimethylamino-2-(4- methyl-benzyl)- l-(4- morpholin-4-yl -phenyl)- butan-1 -one (OMNIRAD 379), 2-methyl-l-[4- (methylthio)phenyl]-2- morpholinopropan-l-one (OMNIRAD 907), Oligo [2 -hydroxy-2 -methyl- 1- [4- (1- methylvinyl)phenyl]propanone] ESACURE ONE (Lamberti S.p.A., Gallarate, Italy), 2- hydroxy-2 -methyl- 1 -phenyl propan-l-one (DAROCUR 1173), 2, 4, 6- trimethylbenzoyldiphenylphosphine oxide (OMNIRAD TPO), and 2, 4, 6 -trimethylbenzoylphenyl phosphinate (OMNIRAD TPO-L). Additional suitable photoinitiators include for example and without limitation, benzyl dimethyl ketal, 2-methyl-2-hydroxypropiophenone, benzoin methyl ether, benzoin isopropyl ether, anisoin methyl ether, aromatic sulfonyl chlorides, photoactive oximes, and combinations thereof.

[0126] In some embodiments, a photoinitiator is present in a photopolymerizable composition in an amount of up to about 5% by weight, based on the total weight of polymerizable components in the photopolymerizable composition. In some cases, a photoinitiator is present in an amount of 0.1 wt.% or more, 0.2 wt.% or more, 0.3 wt.% or more, 0.4 wt.% or more, 0.5 wt.% or more, 0.6 wt.% or more, 0.7 wt.% or more, 0.8 wt.% or more, 0.9 wt.% or more, 1.0 wt.% or more, 1.25 wt.% or more, or 1.5 wt.% or more; and 5 wt.% or less, 4.8 wt.% or less, 4.6 wt.% or less, 4.4 wt.% or less, 4.2 wt.% or less, 4.0 wt.% or less, 3.8 wt.% or less, 3.6 wt.% or less, 3.4 wt.% or less, 3.2 wt.% or less, 3.0 wt.% or less, 2.8 wt.% or less, 2.6 wt.% or less, 2.4 wt.% or less, 2.2 wt.% or less, 2.0 wt.% or less, 1.8 wt.% or less, or 1.6 wt.% or less. Stated another way, the photoinitiator may be present in an amount of about 0.1 to 5% by weight, 0.2 to 5% by weight, 0.5 to 5%, or 0.5 to 3% by weight, based on the total weight of the photopolymerizable composition.

[0127] In some embodiments, an initiator comprises a polymer comprising a free -radical photoinitiator group, e.g., a polymer backbone and pendent photoinitiator groups or terminal photoinitiator groups linked by a polymer chain. In some embodiments, an initiator comprises a macromolecule comprising a photoinitiator group, in which the macromolecule typically has a molecular weight of at least 500 g/mole. Such initiators are described in detail in International Publication No. WO 2019/104072 (Chakraborty et al).

[0128] In certain aspects, the use of more than one initiator assists in increasing the percentage of monomer that gets incorporated into the reaction product of polymerizable components and thus decreasing the percentage of the monomer that remains uncured. In some embodiments, at least one initiator comprises a first free-radical photoinitiator having sufficient absorbance at a first wavelength range; and a second free -radical initiator selected from a second photoinitiator having sufficient absorbance at a second wavelength range, wherein the second wavelength range is different than the first wavelength range, or a thermal free -radical initiator. Such initiator systems are described in detail in International Publication No. WO 2019/104079 (Chakraborty et al).

Urethane Component

[0129] Photopolymerizable compositions of the present disclosure, may comprise no more than a small amount of a urethane component. In some embodiments, the photopolymerizable composition further comprises reaction products including a urethane component. Urethane is obtained as a reaction product of an isocyanate with an alcohol to form carbamate linkages. In some embodiments, the photopolymerizable composition comprises 5% by weight or less of a urethane component. In certain embodiments, the urethane component is present in an amount of 5 wt.% or less, 4 wt.% or less, 3 wt.% or less, 2 wt.% or less, or 1 wt.% or less. It has been discovered that suitable photopolymerizable compositions can be prepared having advantageously low viscosity using a urea or acrylamide component, without requiring the presence of a urethane component. As such, in some cases the photopolymerizable composition is free of a urethane component.

Additives

[0130] Photopolymerizable compositions of the present disclosure, optionally may further comprise at least one additive selected from the group consisting of inhibitors, stabilizing agents, sensitizers, absorption modifiers/ UV absorbers, fillers and combinations thereof.

[0131] In addition, a polymerizable material composition described herein can further comprise one or more sensitizers to increase the effectiveness of one or more photoinitiators that may also be present. In some embodiments, a sensitizer comprises isopropylthioxanthone (ITX) or 2- chlorothioxanthone (CTX). Other sensitizers may also be used. If used in the photopolymerizable composition, a sensitizer can be present in an amount ranging of about 0.01% by weight or about 1 % by weight, based on the total weight of the photopolymerizable composition.

[0132] A photopolymerizable composition described herein optionally comprises one or more polymerization inhibitors or stabilizing agents. A polymerization inhibitor is often included in a photopolymerizable composition to provide additional thermal stability to the composition. A stabilizing agent, in some instances, comprises one or more anti-oxidants. Any anti-oxidant not inconsistent with the objectives of the present disclosure may be used. In some embodiments, for example, suitable anti-oxidants include various aryl compounds, including butylated hydroxytoluene (BHT), which can also be used as a polymerization inhibitor in embodiments described herein. In addition to or as an alternative, a polymerization inhibitor comprises methoxyhydroquinone (MEHQ).

[0133] In some embodiments, a polymerization inhibitor, if used, is present in an amount of about 0.001 to 2% by weight, 0.001 to 1.5% by weight, or 0.001 to 1% by weight, based on the total weight of the photopolymerizable composition. Further, if used, a stabilizing agent is present in a photopolymerizable composition described herein in an amount of about 0.001 to 5% by weight, about 0.001 to 4% by weight, or about 0.001 to 3% by weight, based on the total weight of the photopolymerizable composition.

[0134] A photopolymerizable composition as described herein can also comprise one or more UV absorbers including dyes, optical brighteners, pigments, particulate fillers, etc., to control the penetration depth of actinic radiation. One particularly suitable UV absorber is Tinuvin 326 (2-(5- chloro-2H-benzotriazol-2-yl)-6-(l,l-dimethylethyl)-4-methylphenol, obtained from BASF Corporation, Florham Park, NJ. Another particularly suitable UV absorber that is an optical brightener that is Tinopal OB, a benzoxazole, 2,2'-(2,5-thiophenediyl)bis[5-(l,l-dimethylethyl)], also available from BASF Corporation. [0135] The UV absorber, if used, can be present in an amount of about 0.001 to 5% by weight, about 0.001 to 1% by weight, about 0.001 to 3% by weight, or about 0.001 to 1% by weight, based on the total weight of the photopolymerizable composition.

[0136] In some embodiments, the photopolymerizable compositions of the present disclosure may include at least one methacrylic acid. Methacrylic acid, if used, can be present in an amount of about 0.001 to 10% by weight, about 0.001 to 9.5% by weight, based on the total weight of the photopolymerizable composition.

[0137] Polymerizable compositions of the present disclosure may include fillers, including nanoscale fillers. Examples of suitable fillers are naturally occurring or synthetic materials including, but not limited to: silica (SiCE (e.g., quartz)); alumina (AI2O3), zirconia, nitrides (e.g., silicon nitride); glasses and fillers derived from, for example, Zr, Sr, Ce, Sb, Sn, Ba, Zn, and Al; feldspar; borosilicate glass; kaolin (china clay); talc; zirconia; titania; and submicron silica particles (e.g., pyrogenic silicas, such as those available under the trade designations AEROSIL, including “OX 50, ”“130, ”“150” and “200” silicas from Degussa Corp., Akron, OH and CAB-O-SIL M5 and TS- 720 silica from Cabot Corp., Tuscola, IL). Organic fillers made from polymeric materials are also possible, such as those disclosed in International Publication No. WO09/045752 (Kalgutkar et al.). [0138] The compositions may further contain fibrous reinforcement and colorants, such as dyes, pigments, and pigment dyes. Examples of suitable fibrous reinforcement include poly(glycolic acid) (PGA) microfibrils, collagen microfibrils, and others as described in U.S. Pat. No. 6,183,593 (Narang et al.). Examples of suitable colorants as described in U.S. Pat. No. 5,981,621 (Clark et al.) include l-hydroxy-4-[4-methylphenylamino]-9,10-anthracenedione (FD&C violet No. 2); disodium salt of 6-hydroxy-5-[(4-sulfophenyl)oxo]-2-naphthalenesulfonic acid (FD&C Yellow No. 6); 9-(o- carboxyphenyl)-6-hydroxy-2,4,5,7-tetraiodo-3H-xanthen-3-one, disodium salt, monohydrate (FD&C Red No. 3); and the like.

[0139] Discontinuous fibers are also suitable fillers, such as fibers comprising carbon, ceramic, glass, or combinations thereof. Suitable discontinuous fibers can have a variety of compositions, such as ceramic fibers. The ceramic fibers can be produced in continuous lengths, which are chopped or sheared to provide the discontinuous ceramic fibers. The ceramic fibers can be produced from a variety of commercially available ceramic filaments. Examples of filaments useful in forming the ceramic fibers include the ceramic oxide fibers sold under the trademark NEXTEL (3M Company, St. Paul, MN). NEXTEL is a continuous filament ceramic oxide fiber having low elongation and shrinkage at operating temperatures, and offers good chemical resistance, low thermal conductivity, thermal shock resistance, and low porosity. Specific examples of NEXTEL fibers include NEXTEL 312, NEXTEL 440, NEXTEL 550, NEXTEL 610 and NEXTEL 720. NEXTEL 312 and NEXTEL 440 are refractory aluminoborosilicate that includes AI2O3, SiCL and B2O3. NEXTEL 550 and NEXTEL 720 are aluminosilica and NEXTEL 610 is alumina. During manufacture, the NEXTEL filaments are coated with organic sizing or finishes which serves as aid in textile processing. Sizing can include the use of starch, oil, wax or other organic ingredients applied to the filament strand to protect and aid handling. The sizing can be removed from the ceramic filaments by heat cleaning the filaments or ceramic fibers as a temperature of 700 °C for one to four hours.

[0140] The ceramic fibers can be cut, milled, or chopped so as to provide relatively uniform lengths, which can be accomplished by cutting continuous filaments of the ceramic material in a mechanical shearing operation or laser cutting operation, among other cutting operations. Given the highly controlled nature of certain cutting operations, the size distribution of the ceramic fibers is very narrow and allow to control the composite property. The length of the ceramic fiber can be determined, for instance, using an optical microscope (Olympus MX61, Tokyo, Japan) fit with a CCD Camera (Olympus DP72, Tokyo, Japan) and analytic software (Olympus Stream Essentials, Tokyo, Japan). Samples may be prepared by spreading representative samplings of the ceramic fiber on a glass slide and measuring the lengths of at least 200 ceramic fibers at 10X magnification.

[0141] Suitable fibers include for instance ceramic fibers available under the trade name NEXTEL (available from 3M Company, St. Paul, MN), such as NEXTEL 312, 440, 610 and 720. One presently preferred ceramic fiber comprises poly crystalline 01-AI2O3. Suitable alumina fibers are described, for example, in U.S. Pat. No. 4,954,462 (Wood et al.) and U.S. Pat. No. 5, 185,299 (Wood et al.). Exemplary alpha alumina fibers are marketed under the trade designation NEXTEL 610 (3M Company, St. Paul, MN). In some embodiments, the alumina fibers are poly crystalline alpha alumina fibers and comprise, on a theoretical oxide basis, greater than 99 percent by weight AI2O3 and 0.2-0.5 percent by weight S1O2, based on the total weight of the alumina fibers. In other embodiments, some desirable poly crystalline, alpha alumina fibers comprise alpha alumina having an average grain size of less than one micrometer (or even, in some embodiments, less than 0.5 micrometer). In some embodiments, poly crystalline, alpha alumina fibers have an average tensile strength of at least 1.6 GPa (in some embodiments, at least 2.1 GPa, or even, at least 2.8 GPa). Suitable aluminosilicate fibers are described, for example, in U.S. Pat. No. 4,047,965 (Karst et al). Exemplary aluminosilicate fibers are marketed under the trade designations NEXTEL 440, and NEXTEL 720, by 3M Company (St. Paul, MN). Aluminoborosilicate fibers are described, for example, in U.S. Pat. No. 3,795,524 (Sowman). Exemplary aluminoborosilicate fibers are marketed under the trade designation NEXTEL 312 by 3M Company. Boron nitride fibers can be made, for example, as described in U.S. Pat. No. 3,429,722 (Economy) and U.S. Pat. No. 5,780,154 (Okano et al).

[0142] Ceramic fibers can also be formed from other suitable ceramic oxide filaments. Examples of such ceramic oxide filaments include those available from Central Glass Fiber Co., Ltd. (e.g., EFH75-01, EFH150-31). Also preferred are aluminoborosilicate glass fibers, which contain less than about 2% alkali or are substantially free of alkali (i.e.,“E-glass” fibers). E-glass fibers are available from numerous commercial suppliers.

[0143] Examples of useful pigments include, without limitation: white pigments, such as titanium oxide, zinc phosphate, zinc sulfide, zinc oxide and lithopone; red and red-orange pigments, such as iron oxide (maroon, red, light red), iron/chrome oxide, cadmium sulfoselenide and cadmium mercury (maroon, red, orange); ultramarine (blue, pink and violet), chrome-tin (pink) manganese (violet), cobalt (violet); orange, yellow and buff pigments, such as barium titanate, cadmium sulfide (yellow), chrome (orange, yellow), molybdate (orange), zinc chromate (yellow), nickel titanate (yellow), iron oxide (yellow), nickel tungsten titanium, zinc ferrite and chrome titanate; brown pigments, such as iron oxide (buff, brown), manganese/antimony/titanium oxide, manganese titanate, natural siennas (umbers), titanium tungsten manganese; blue-green pigments, such as chrome aluminate (blue), chrome cobalt-alumina (turquoise), iron blue (blue), manganese (blue), chrome and chrome oxide (green) and titanium green; as well as black pigments, such as iron oxide black and carbon black. Combinations of pigments are generally used to achieve the desired color tone in the cured composition.

[0144] The use of florescent dyes and pigments can also be beneficial in enabling the printed composition to be viewed under black-light. A particularly useful hydrocarbon soluble fluorescing dye is 2.5-bis(5-/ -butyl-2-benzoxazolyl) 1 thiophene. Fluorescing dyes, such as rhodamine, may also be bound to cationic polymers and incorporated as part of the resin.

[0145] If desired, the compositions of the disclosure may contain other additives, such as indicators, accelerators, surfactants, wetting agents, tartaric acid, chelating agents, buffering agents, and other similar ingredients that will be apparent to those skilled in the art. Additionally, medicaments or other therapeutic substances can be optionally added to the photopolymerizable compositions. Examples include, but are not limited to, fluoride sources, whitening agents, anticaries agents (e.g., xylitol), remineralizing agents (e.g., calcium phosphate compounds and other calcium sources and phosphate sources), enzymes, breath fresheners, anesthetics, clotting agents, acid neutralizers, chemotherapeutic agents, immune response modifiers, thixotropes, polyols, anti-inflammatory agents, antimicrobial agents, antifungal agents, agents for treating xerostomia, desensitizers, and the like, of the type often used in dental compositions.

[0146] Combinations of any of the above additives may also be employed. The selection and amount of any one such additive can be selected by one of skill in the art to accomplish the desired result without undue experimentation.

[0147] Photopolymerizable compositions materials herein can also exhibit a variety of desirable properties, non-cured, cured, and as post-cured articles. A photopolymerizable composition, when non-cured, has a viscosity profile consistent with the requirements and parameters of one or more additive manufacturing devices (e.g., 3D printing systems). Advantageously, in many embodiments, the photopolymerizable composition contains a minimal amount of solvent. For instance, the composition may comprise 95% to 100% solids, preferably 100% solids. In some instances, a photopolymerizable composition described herein when non-cured exhibits viscosity of less than 5000 centipoises (cP), when measured by a cone and plate rheometer at a temperature of 20 degrees Celsius and at a shear rate of 1 1/s. In some cases, a photopolymerizable composition described herein when non-cured exhibits viscosity of 4800 cP or less, 4700 cP or less, 4500 cP or less, 4300 cP or less, 4100 cP or less, 3900 cP or less, 3500 cP or less, 3000 cP or less, 2500 cP or less, 2000 cP or less; and 300 cP or more, 350 cP or more, 400 cP or more, 500 cP or more, 600 cP or more, 700 cP or more, 800 cP or more, 900 cP or more, 1000 cP or more, 1100 cp or more, or 1500 cp or more. In some cases, a photopolymerizable composition described herein when non-cured exhibits a dynamic viscosity of less than 2000 cP at 40 °C, 1900 cP or less, 1800 cP or less, 1500 cP or less, 1300 cP or less, or 1100 cP or less; and 800 cP or more, 900 cP or more, or 1000 cP or more. In some cases, a photopolymerizable composition described herein when non-cured exhibits a dynamic viscosity of less than 400 cP at 60°C, or 380 cP or less, 360 cP or less, 330 cP or less, or 300 cP or less; and 200 cP or more, 230 cP or more, 250 cP or more, or 280 cP or more.

Orthodontic Articles

[0148] In a second aspect, the present disclosure provides an orthodontic article. The orthodontic article includes a polymerized reaction product of a photopolymerizable composition. The photopolymerizable composition includes a) 45-60 wt.% of the at least one (meth)acrylate reactive diluent, based on a total weight of the photopolymerizable composition; b) a photoinitiator; c) SOSO wt.% of a first polymerization reaction product of components, based on the total weight of the photopolymerizable composition, the components comprising: a first polyether polyamine; and an ethylenically-unsaturated isocyanate functional monomer, d) optionally up to 10 wt.% of a crosslinker having a glass transition temperature (T_g) of 50°C or greater; and e) optionally up to 12 wt.% of a second polymerization reaction product of components, based on the total weight of the photopolymerizable composition, the components comprising a second polyether polyamine; and an ethylenically-unsaturated isocyanate functional monomer. The photopolymerizable composition includes the first polymerization reaction product of components in an amount of 40-50 wt.%, and the composition contains no more than 5 wt.% of the second polymerization reaction product of components. The photopolymerizable composition includes the first polymerization reaction product of components in an amount of 30 wt.% to less than 40 wt.%, then the composition includes at least one of 55-60 wt.% of the (meth) acrylate reactive diluent, 5-12 wt.% of the second polymerization reaction product of components, 5-10 wt.% of the crosslinker, or 1-10 wt.% of methacrylic acid. The polymerized reaction product has a T_g of 50°C or greater.

[0149] In a third aspect, an orthodontic article is provided. The orthodontic article includes a polymerized reaction product of a photopolymerizable composition. The photopolymerizable composition includes 30-50 wt.% of the (meth)acrylate reactive diluent; and 40-60 wt.% of the polymerization reaction product of components, the components comprising: a polymeric diol; and an azlactone. The polymerized reaction product has a T_g of 50 °C or greater.

[0150] A polymerized reaction product of a photopolymerizable composition according to the above disclosure comprises a shape of an orthodontic article. The conformability and durability of a cured orthodontic article made from the photopolymerizable compositions of the present disclosure can be determined in part by standard tensile, modulus, and/or elongation testing. The photopolymerizable compositions can typically be characterized by at least one of the following parameters after hardening.

[0151] As orthodontic articles are used in the moisture-rich environment of a patient’s mouth, the extent of water absorption is relevant to the composition of an orthodontic article. Select articles absorb less than 1%, less than 0.5%, less than 0. 2%, or even less than 0.1% water, when soaked in deionized water at a temperature of 20 to 25 °C for 72 hours.

[0152] The orthodontic article preferably exhibits at least one desirable physical property. These physical properties include the following: initial relaxation modulus, Young’s modulus, tensile stress at break, tensile strain at break, and exhibiting peaks in loss modulus and tan delta with large temperature separation, and percent weight of water absorption. Preferably, the orthodontic article exhibits at least two different desirable physical properties, more preferably at least three different desirable physical properties, and most preferably desirable Young’s modulus, tensile stress at break and tensile strain at break. The values of these different physical properties are described below.

[0153] An orthodontic article optionally exhibits tensile stress at break (or maximum) or tensile strength of 15 MPa or greater as determined according to ASTM-D638-14. Strength at yield (i.e., yield strength) is defined as the maximum tensile stress a material can handle before it is permanently deformed. Tensile stress at break refers to the point on the stress-strain curve where the material breaks. Samples that yield can undergo strain hardening by deformation, prior to breaking. The stress strain curves for brittle materials, however, do not have a yield point and are typically linear over the full range of strain, eventually terminating in fracture at a maximum tensile strength without appreciable plastic flow.

[0154] In certain embodiments, a polymerized composition (e.g., an orthodontic article) exhibits Young’s modulus of 175 MPa or greater, tensile strain at break of 65% or greater, and tensile stress at break of 15 MPa or greater, as determined according to ASTM D638-14. In select embodiments, an orthodontic article exhibits Young’s modulus of 175 MPa, tensile strain at break of 65%, and a tensile stress at break of 15 MPa. In certain embodiments, a polymerized composition (e.g., an orthodontic article) exhibits Young’s modulus of 300 MPa or greater, tensile strain at break of 65% or greater, and a tensile stress at break of 15 MPa or greater, as determined according to ASTM D638-14. In select embodiments, an orthodontic article exhibits Young’s modulus of 300 MPa, tensile strain at break of 65%, and a tensile stress at break of 15 MPa. Similarly, an article may exhibit any combination of the preferred values described above, of each of the Young’s modulus, tensile stress at break, and tensile strain at break. It was unexpectedly found that photopolymerizable compositions according to at least certain embodiments are capable of forming articles simultaneously having all three of these physical properties.

[0155] In certain embodiments, a polymerized composition (e.g., a dental restoration tool or mold) exhibits Young’s modulus of 500 MPa or greater, tensile strain at break of 4% or greater, and tensile stress at break of 25 MPa or greater, as determined according to ASTM D638-14.

[0156] In select embodiments, dynamic mechanical analysis of articles, according to the present disclosure, display a peak in the loss modulus below 20 °C, more preferably below 15 °C, most preferably below 10 °C. In some embodiments, the peak loss modulus temperature is at least -70 °C, -60 °C, or -50 °C. The term peak does not necessarily mean the global maximum value in loss modulus, but can be a local maximum value, or a shoulder on a larger peak. These articles tend to display high levels of elongation at break. In other embodiments, articles may display a tan delta peak > 70 °C, > 75 °C, more preferably >78 °C, most preferably >80 °C. In some embodiments, the peak tan delta temperature is no greater than 150 °C, 140 °C, 135 °C, 130 °C, 120 °C or 110 °C. Articles which displayed Young’s modulus of 175 MPa or greater and a tensile stress at break of 15 megapascals (MPa) or greater displayed a peak in the loss modulus below 20 °C and a tan delta peak greater than 70 °C. Articles which displayed Young’s modulus of 300 MPa or greater and a tensile stress at break of 15 megapascals (MPa) or greater displayed a peak in the loss modulus below 20 °C and a tan delta peak greater than 70 °C. In some embodiments, an article has a first phase having a peak loss modulus temperature of less than 0, -5, or -10 °C and a second phase having a peak tan delta temperature greater than 30, 40, 50, 60, 70, or 80 °C as determined according to dynamic mechanical analysis after conditioning in deionized water at 37 °C for 24 hours. Loss modulus and tan delta are explained, for instance, in Sepe, M.P. (1998 Dynamic Mechanical Analysis for Plastics Engineering. William Andrew Publishing/Plastics Design Library).

[0157] In select embodiments, the orthodontic article according to the present disclosure, optionally exhibits an initial relaxation modulus of 2 megapascals (MPa) or greater measured at 37° C under 95% humidity, and 1% strain, as determined by Dynamic Mechanical Analysis (DMA) following conditioning (i.e., soaking) of a sample of the material of the orthodontic article in deionized water for 48 hours at room temperature (i.e., 22 to 25° C.) (“Water Conditioning”). The DMA procedure is described in detail in the Examples below. Preferably, an orthodontic article exhibits an initial relaxation modulus of 2 MPa or greater, 3 MPa or greater, 4 MPa or greater, 5 MPa or greater, 6 MPa or greater, 7 MPa or greater, 8 MPa or greater, or 9 MPa or greater. In some embodiments, the initial relaxation modulus is no greater than about 15, 14, 13, 12, 11 or 10 MPa.

[0158] In select embodiments, the orthodontic article according to the present disclosure, optionally exhibits a (e.g., 30 minute) relaxation modulus of 100 MPa or greater as determined by DMA at 37° C under 95% humidity following overnight soaking in water under a 1% strain on for 11 hours followed by strain recovery measurement with 0 MPa stress for 1 hour. The DMA procedure for relaxation modulus is described in detail in the Examples below, and is performed on a sample of the material of the orthodontic article following water conditioning and initial relaxation modulus testing. Preferably, an orthodontic article exhibits a (e.g., 11 hours) relaxation modulus of 0.1 MPa or greater.

[0159] In select embodiments, the orthodontic article according to the present disclosure, optionally exhibits a percent loss of relaxation modulus of 70% or more as determined by DMA. The loss is determined by comparing the initial relaxation modulus to the relaxation modulus at 37° C under 95% humidity and 1% strain. It was discovered that orthodontic articles according to at least certain embodiments of the present disclosure exhibit a loss in relaxation modulus following exposure to water than articles made of different materials. Preferably, an orthodontic article exhibits loss of relaxation modulus of 99% or less, 90% or less, or 85% or less. In some embodiments, the loss of relaxation modulus is 80%, 85%, or 90% or greater.

[0160] In at least certain embodiments of orthodontic articles of the present disclosure, the articles are advantageously more resistant to staining than articles made from different, more hydrophilic components. For instance, dyes and other colored materials in beverages are typically hydrophilic, thus they will have a greater affinity for a more hydrophilic composition than a more hydrophobic composition.

[0161] The above mechanical properties are particularly well suited for orthodontic articles that require resiliency and flexibility, along with adequate wear strength and long term durability.

Methods

[0162] In a fourth aspect, the present disclosure provides a method of making an orthodontic article. The method comprises: a) providing a photopolymerizable composition comprising: 30-60 wt.% of at least one (meth) acrylate reactive diluent; a photoinitiator; and 30-60 wt.% of a polymerization reaction product of components comprising a urea functional component or an acrylamide functional component, wherein the photopolymerizable composition exhibits a dynamic viscosity of less than 5000 centipoises (cP), when measured by a cone and plate rheometer at a temperature of 20 degrees Celsius and at a shear rate of 1 1/s; b) selectively curing the photopolymerizable composition; and c) repeating steps a) and b) to form multiple layers and create the orthodontic article. The method optionally includes d) curing unpolymerized photopolymerizable composition remaining after step c). The method further optionally includes e) removing at least a portion of the unpolymerized photopolymerizable composition remaining after step c). In cases where both optional steps d) and e) are performed, step e) is typically performed before step d).

[0163] Polymerizable (e.g., photopolymerizable) components described herein can be mixed by known techniques. In some embodiments, for instance, a method for the preparation of a photopolymerizable composition described herein comprises the steps of mixing all or substantially all of the components of the composition, heating the mixture, and optionally filtering the heated mixture. Softening the mixture, in some embodiments, is carried out at a temperature of about 50 °C or in a range from about 50 °C to about 85 °C. In some embodiments, a photopolymerizable composition described herein is produced by placing all or substantially all components of the composition in a reaction vessel and heating the resulting mixture to a temperature ranging from about 50 °C to about 85 °C with stirring. The heating and stirring are continued until the mixture attains a substantially homogenized state.

[0164] In many embodiments, the photopolymerizable composition is vat polymerized, as discussed in detail below.

[0165] The shape of the article is not limited, and typically comprises a shaped integral (e.g., unitary) article, in which more than one variation in dimension is provided by a single integral article. For example, the article can comprise one or more channels, one or more undercuts, one or more perforations, or combinations thereof. Such features are typically not possible to provide in an integral article using conventional molding methods.

[0166] The components of the photopolymerizable (e.g., polymerizable) composition are as discussed in detail above. In many embodiments, the photopolymerizable composition is cured using actinic radiation comprising UV radiation, e-beam radiation, visible radiation, or a combination thereof. Moreover, the method optionally further comprises post curing the orthodontic article using actinic radiation.

[0167] In certain embodiments, the method comprises vat polymerization of the photopolymerizable composition. When vat polymerization is employed, the radiation may be directed through a wall of a container (e.g., a vat) holding the photopolymerizable composition, such as a side wall or a bottom wall.

[0168] A photopolymerizable composition described herein in a cured state, in some embodiments, can exhibit one or more desired properties. A polymerizable composition in a “cured” state can comprise a photopolymerizable composition that includes a polymerizable component that has been at least partially polymerized and/or crosslinked. For instance, in some instances, a cured article is at least about 10% polymerized or crosslinked or at least about 30% polymerized or crosslinked. In some cases, a cured polymerizable composition is at least about 50%, at least about 70%, at least about 80%, or at least about 90% polymerized or crosslinked. A cured polymerizable composition can also be between about 10% and about 99% polymerized or crosslinked.

Fabricating an Orthodontic Article

[0169] Once prepared as set forth above, the polymerizable (e.g., photopolymerizable) compositions of the present disclosure may be used in myriad additive manufacturing processes to create a variety of e.g., orthodontic articles. A generalized method 100 for creating three- dimensional articles is illustrated in FIG. 1. Each step in the method will be discussed in greater detail below. First, in Step 110 the desired photopolymerizable composition (e.g., comprising at least one (meth) acrylate reactive diluent) is provided and introduced into a reservoir, cartridge, or other suitable container for use by or in an additive manufacturing device. The additive manufacturing device selectively cures the photopolymerizable composition according to a set of computerized design instructions in Step 120. In Step 130, Step 110 and/or Step 120 is repeated to form multiple layers to create the article comprising a three-dimensional structure (i.e., an orthodontic article). Optionally uncured photopolymerizable composition is removed from the article in Step 140, further optionally, the article is subjected to additional curing to polymerize remaining uncured photopolymerizable components in the article in Step 150, and yet further optionally, the article is subjected to a heat treatment in Step 160.

[0170] Methods of printing a three-dimensional article or object described herein can include forming the article from a plurality of layers of a photopolymerizable composition described herein in a layer-by-layer manner. Further, the layers of a build material composition can be deposited according to an image of the three-dimensional article in a computer readable format. In some or all embodiments, the photopolymerizable composition is deposited according to preselected computer aided design (CAD) parameters.

[0171] Additionally, it is to be understood that methods of manufacturing a 3D article described herein can include so-called “stereolithography/vat polymerization” 3D printing methods. Other techniques for three-dimensional manufacturing are known, and may be suitably adapted to use in the applications described herein. More generally, three-dimensional fabrication techniques continue to become available. All such techniques may be adapted to use with photopolymerizable compositions described herein, provided they offer compatible fabrication viscosities and resolutions for the specified article properties. Fabrication may be performed using any of the fabrication technologies described herein, either alone or in various combinations, using data representing a three-dimensional object, which may be reformatted or otherwise adapted as necessary for a particular printing or other fabrication technology.

[0172] It is entirely possible to form a 3D article from a photopolymerizable composition described herein using vat polymerization (e.g., stereolithography). For example, in some cases, a method of printing a 3D article comprises retaining a photopolymerizable composition described herein in a fluid state in a container and selectively applying energy to the photopolymerizable composition in the container to solidify at least a portion of a fluid layer of the photopolymerizable composition, thereby forming a hardened layer that defines a cross-section of the 3D article.

[0173] Additionally, a method described herein can further comprise raising or lowering the hardened layer of photopolymerizable composition to provide a new or second fluid layer of unhardened photopolymerizable composition at the surface of the fluid in the container, followed by again selectively applying energy to the photopolymerizable composition in the container to solidify at least a portion of the new or second fluid layer of the photopolymerizable composition to form a second solidified layer that defines a second cross-section of the 3D article. Further, the first and second cross-sections of the 3D article can be bonded or adhered to one another in the z-direction (or build direction corresponding to the direction of raising or lowering recited above) by the application of the energy for solidifying the photopolymerizable composition. Moreover, selectively applying energy to the photopolymerizable composition in the container can comprise applying actinic radiation, such as UV radiation, visible radiation, or e-beam radiation, having a sufficient energy to cure the photopolymerizable composition. A method described herein can also comprise planarizing a new layer of fluid photopolymerizable composition provided by raising or lowering an elevator platform. Such planarization can be carried out, in some cases, by utilizing a wiper or roller or a recoater. Planarization corrects the thickness of one or more layers prior to curing the material by evening the dispensed material to remove excess material and create a uniformly smooth exposed or flat up-facing surface on the support platform of the printer.

[0174] It is further to be understood that the foregoing process can be repeated a selected number of times to provide the 3D article. For example, in some cases, this process can be repeated “n” number of times. Further, it is to be understood that one or more steps of a method described herein, such as a step of selectively applying energy to a layer of photopolymerizable composition, can be carried out according to an image of the 3D article in a computer-readable format. Suitable stereolithography printers include the Viper Pro SLA, available from 3D Systems, Rock Hill, SC and the Asiga PICO PLUS 39, available from Asiga USA, Anaheim Hills, CA.

[0175] FIG. 2 shows an exemplary stereolithography apparatus (“SLA”) that may be used with the photopolymerizable compositions and methods described herein. In general, the SLA 200 may include a laser 202, optics 204, a steering lens 206, an elevator 208, a platform 210, and a straight edge 212, within a vat 214 filled with the photopolymerizable composition. In operation, the laser 202 is steered across a surface of the photopolymerizable composition to cure a cross-section of the photopolymerizable composition, after which the elevator 208 slightly lowers the platform 210 and another cross section is cured. The straight edge 212 may sweep the surface of the cured composition between layers to smooth and normalize the surface prior to addition of a new layer. In other embodiments, the vat 214 may be slowly filled with liquid resin while an article is drawn, layer by layer, onto the top surface of the photopolymerizable composition.

[0176] A related technology, vat polymerization with Digital Light Processing (“DLP”), also employs a container of curable polymer (e.g., photopolymerizable composition). However, in a DLP based system, a two-dimensional cross section is projected onto the curable material to cure the desired section of an entire plane transverse to the projected beam at one time. All such curable polymer systems as may be adapted to use with the photopolymerizable compositions described herein are intended to fall within the scope of the term “vat polymerization system” as used herein. In certain embodiments, an apparatus adapted to be used in a continuous mode may be employed, such as an apparatus commercially available from Carbon 3D, Inc. (Redwood City, CA), for instance as described in U.S. Patent Nos. 9,205,601 and 9,360,757 (both to DeSimone et al.).

[0177] Referring to FIG. 5, a general schematic is provided of another SLA apparatus that may be used with photopolymerizable compositions and methods described herein. In general, the apparatus 500 may include a laser 502, optics 504, a steering lens 506, an elevator 508, and a platform 510, within a vat 514 filled with the photopolymerizable composition 519. In operation, the laser 502 is steered through a wall 520 (e.g., the floor) of the vat 514 and into the photopolymerizable composition to cure a cross-section of the photopolymerizable composition 519 to form an article 517, after which the elevator 508 slightly raises the platform 510 and another cross section is cured. [0178] More generally, the photopolymerizable composition is typically cured using actinic radiation, such as UV radiation, e-beam radiation, visible radiation, or any combination thereof. The skilled practitioner can select a suitable radiation source and range of wavelengths for a particular application without undue experimentation.

[0179] After the 3D article has been formed, it is typically removed from the additive manufacturing apparatus and cleaned, (e.g., an ultrasonic, or bubbling, or spray rinse in a solvent, which would dissolve a portion of the uncured photopolymerizable composition but not the cured, solid state article (e.g., green body). Any other conventional method for cleaning the article and removing uncured material at the article surface may also be utilized. In some embodiments, removing uncured material from the article comprises directing pressurized gas at the uncured photopolymerizable composition to force at least a portion of the composition off the article surface, e.g., using an air knife. In some embodiments, removing uncured material at the article surface comprises moving the article and thereby generating a mass inertial force in uncured photopolymerizable composition disposed on the article, thus forming a coating layer of uncured photopolymerizable composition on the article. The mass inertial force can be generated using a centrifuge, a shaker, or a mixer that spins along one or more axes. Suitable ways of generating a mass inertial force are described, for instance, in International Publication No. WO 2020/157598 (Chakraborty et al.), incorporated herein by reference in its entirety. For instance, the source of the mass inertial force may be generated using a centrifuge, a shaker, or a mixer that spins along one or more axes. In some embodiments, the moving of the object is a rotation or spinning of the object. Accordingly, the mass inertial force may be generated by a centrifugal force. One suitable mixer that spins along more than one axis is a dual asymmetric centrifugal mixer, such as the DAC 400 FVZ available from Flacktek, Landrum, SC. A dual asymmetric centrifugal mixer provides simultaneous dual axis spinning that automatically reorients the article during spinning, which tends to pull uncured composition out of concave features of the article in a short period of time (e.g., 20, 15, or 10 seconds or less). At this stage, the three-dimensional article typically has sufficient green strength for handling in the remaining optional steps of method 100.

[0180] It is expected in certain embodiments of the present disclosure that the formed article obtained in Step 120 will shrink (i.e., reduce in volume) such that the dimensions of the article after (optional) Step 150 will be smaller than expected. For example, a cured article may shrink less than 5% in volume, less than 4%, less than 3%, less than 2%, or even less than 1% in volume, which is contrast to other compositions that provide articles that shrink about 6-8% in volume upon optional post curing. The amount of volume percent shrinkage will not typically result in a significant distortion in the shape of the final object. It is particularly contemplated, therefore, that dimensions in the digital representation of the eventual cured article may be scaled according to a global scale factor to compensate for this shrinkage. For example, in some embodiments, at least a portion of the digital article representation can be at least 101% of the desired size of the printed appliance, in some embodiments at least 102%, in some embodiments at least 104%, in some embodiments, at least 105%, and in some embodiments, at least 110%.

[0181] A global scale factor may be calculated for any given photopolymerizable composition formulation by creating a calibration part according to Steps 110 and 120 above. The dimensions of the calibration article can be measured prior to post curing.

[0182] In general, the three-dimensional article formed by initial additive manufacturing in Step 120, as discussed above, is not fully cured, by which is meant that not all of the photopolymerizable material in the composition has polymerized even after rinsing. Some uncured photopolymerizable material is typically removed from the surface of the printed article during a cleaning process (e.g., optional Step 140). The article surface, as well as the bulk article itself, typically still retains uncured photopolymerizable material, suggesting further cure.

[0183] Removing residual uncured photopolymerizable composition is particularly useful when the article is going to subsequently be post cured, to minimize uncured residual photopolymerizable composition from undesirably curing directly onto the article.

[0184] Further curing can be accomplished by further irradiating with actinic radiation, heating, or both. Exposure to actinic radiation can be accomplished with any convenient radiation source, generally UV radiation, visible radiation, and/or e-beam radiation, for a time ranging from about 10 to over 60 minutes. Heating is generally carried out at a temperature in the range of about 75- 150°C, for a time ranging from about 10 to over 60 minutes in an inert atmosphere. So called post cure ovens, which combine UV radiation and thermal energy, are particularly well suited for use in the post cure processes of Step 150 and/or Step 160. In general, post curing improves the mechanical properties and stability of the three-dimensional article relative to the same three- dimensional article that is not post cured.

[0185] One particularly attractive opportunity for 3D printing is in the direct creation of dental restorative tool or a mold. The dental restorative tool is custom designed and preformed for a particular tooth (or set of teeth) of a particular patient. For use as a dental restoration tool or mold, the photopolymerizable resin from which it is made must be capable of printing at sufficiently high resolution to achieve small features like interproximal fins/spacers and hinges. Further, the cured resin must be of sufficient modulus to resist deformation pressure by the restoration material as it fills the mold. The cured resin must also be tough enough to be handled and fitted over the teeth without breaking. Preferably, the material does not undergo rapid physical or chemical aging and embrittlement. In some cases, the cured material must exhibit at least one of a Young’s modulus of 500 MPa or greater, tensile strain at break of 4% or greater, or tensile stress at break of 25 MPa or greater, each as determined according to ASTM D638-14. In certain cases, the cured material exhibits at least two of these physical characteristics, or even all three.

[0186] In some examples, such custom tools may be produced using three-dimensional printing techniques. Tools may also be produced by other methods of creating physical objects from digital data, such as CAD/CAM milling. In other examples, tools may be produced using vacuum forming techniques.

[0187] In one example, a tool for forming a dental restoration comprises a preformed mold body configured to provide a patient-specific, customized fit with at least one tooth to be restored of a patient, the mold body configured to align with a portion of a surface of the at least one tooth, the mold body being configured to combine with the at least one tooth to define a mold cavity encompassing at least a portion of desired tooth structure of the at least one tooth to be restored of the patient, wherein the portion of desired tooth structure of the at least one tooth to be restored defines a transition from a supragingival surface of the at least one tooth to a subgingival surface of the at least one tooth.

[0188] Custom tools may be formed based on a digital model of the teeth and mouth of an individual patient, which can be produced by an intra-oral 3D scan, such as an intraoral scanner. In one particular example, the custom tools may be digitally designed using CAD software, such as solid modeling software based on the digital model of the planned restored dentition. A custom tool may be designed to fit over the tooth or teeth to be restored (the restorative portion) and a portion of the neighboring teeth (the engagement portions). Production may optionally include other steps such as, curing (e.g., in a UV chamber) and/or cleaning, e.g., in alcohol solution. Engagement portions may be located in regions which correspond to regions of the teeth where they will extend from. Within the digital model, the design may be segmented into two sections (facial mold body and lingual mold body) to facilitate eventual assembly of the tool components on the teeth, with specific geometric interferences selected related to the arch lengths to provide the desired clamping forces. Within the digital model, engagement portions with certain interlocking geometries are designed, selecting overall heights of the engagement portions based where the engagement portions are placed within the patient’s mouth. The components within the CAD software may be converted into a 3D point mesh file or other format to facilitate production with a 3D printer, for instance. In some cases, a dental restorative tool or mold comprises a polymerized reaction product of a photopolymerizable composition according to at least certain embodiments described herein.

[0189] Suitable dental restoration tools and molds and methods of making them may be as described in detail in U.S. Patent Nos. 10,722,331, 11,123,165, 11,185,392, (each to Hansen et al.), and 11,547,530 (Dingeldein et al.); U.S. Publication Nos. 2019/0083208, 2023/0042808 (each to Hansen et al.), 2019/0298489, and 2021/0290349 (each to Dingeldein et al.); and International Publication Nos. WO 2023/031771, WO 2023/031761, and WO 2023/031766 (each to Hansen et al.).

[0190] Another opportunity for 3D printing is in the direct creation of orthodontic clear tray aligners. These trays, also known as aligners or polymeric or shell appliances, are provided in a series and are intended to be worn in succession, over a period of months, in order to gradually move the teeth in incremental steps towards a desired target arrangement. Some types of clear tray aligners have a row of tooth-shaped receptacles for receiving each tooth of the patient’s dental arch, and the receptacles are oriented in slightly different positions from one appliance to the next in order to incrementally urge each tooth toward its desired target position by virtue of the resilient properties of the polymeric material. A variety of methods have been proposed in the past for manufacturing clear tray aligners and other resilient appliances. Typically, positive dental arch models are fabricated for each dental arch using additive manufacturing methods, such as stereolithography described above. Subsequently, a sheet of polymeric material is placed over each of the arch models and formed under heat, pressure and/or vacuum to conform to the model teeth of each model arch. The formed sheet is cleaned and trimmed as needed and the resulting arch-shaped appliance is shipped along with the desired number of other appliances to the treating professional.

[0191] An aligner or other resilient appliance created directly by 3D printing would eliminate the need to print a mold of the dental arch and further thermoform the appliance. It also would allow new aligner designs and give more degrees of freedom in the treatment plan. Exemplary methods of direct printing clear tray aligners and other resilient orthodontic apparatuses are set forth in PCT Publication Nos. W02016/109660 (Raby et al.), WO2016/148960 (Cinader et al.), and W02016/149007 (Oda et al.) as well as US Publication Nos. US2011/0091832 (Kim, et al.) and US2013/0095446 (Kitching).

[0192] The following describes general methods for creating a clear tray aligner as printed appliance 300 (FIG. 3). However, other dental and orthodontic articles can be created using similar techniques and the photopolymerizable compositions of the present disclosure. Representative examples include, but are not limited to, the removable appliances having occlusal windows described in International Application Publication No. W02016/109660 (Raby et al.), the removable appliances with a palatal plate described in US Publication No. 2014/0356799 (Cinader et al); the resilient polymeric arch members described in International Application Nos. WO2016/148960 and W02016/149007 (Oda et al.) as well as US Publication No. 2008/0248442 (Cinader et al.); and molding techniques and tools for forming a dental restoration in a mouth as described in WO2016/094272 (Hansen et al.) and US Publication No. 2019/0083208 (Hansen et al.). Moreover, the photopolymerizable compositions can be used in the creation of indirect bonding trays, such as those described in International Publication No. WO2015/094842 (Paehl et al.) and US Publication No. 2011/0091832 (Kim, et al.) and other dental articles, including but not limited to crowns, bridges, veneers, inlays, onlays, fillings, and prostheses (e.g., partial or full dentures). Other orthodontic appliances and devices include, but not limited to, orthodontic brackets, buccal tubes, lingual retainers, orthodontic bands, class II and class III correctors, sleep apnea devices, bite openers, buttons, cleats, and other attachment devices.

Fabricating an Orthodontic Appliance with the Photopolymerizable Compositions

[0193] One particularly interesting implementation of an article is generally depicted in FIG. 3. The additive manufactured article 300 is a clear tray aligner and is removably positionable over some or all of a patient’s teeth. In some embodiments, the appliance 300 is one of a plurality of incremental adjustment appliances. The appliance 300 may comprise a shell having an inner cavity. The inner cavity is shaped to receive and resiliently reposition teeth from one tooth arrangement to a successive tooth arrangement. The inner cavity may include a plurality of receptacles, each of which is adapted to connect to and receive a respective tooth of the patient's dental arch. The receptacles are spaced apart from each other along the length of the cavity, although adjoining regions of adjacent receptacles can be in communication with each other. In some embodiments, the shell fits over all teeth present in the upper jaw or lower jaw. Typically, only certain one(s) of the teeth will be repositioned while others of the teeth will provide a base or anchor region for holding the dental appliance in place as it applies the resilient repositioning force against the tooth or teeth to be treated.

[0194] In order to facilitate positioning of the teeth of the patient, at least one of the receptacles may be aligned to apply rotational and/or translational forces to the corresponding tooth of the patient when the appliance 300 is worn by the patient in order to eventually align said tooth to a new desired position. In some particular examples, the appliance 300 may be configured to provide only compressive or linear forces. In the same or different examples, the appliance 300 may be configured to apply translational forces to one or more of the teeth within receptacles.

[0195] In some embodiments, the shell of the appliance 300 fits over some or all anterior teeth present in an upper jaw or lower jaw. Typically, only certain one(s) of the teeth will be repositioned while others of the teeth will provide a base or anchor region for holding the appliance in place as it applies the resilient repositioning force against the tooth or teeth to be repositioned. An appliance 300 can accordingly be designed such that any receptacle is shaped to facilitate retention of the tooth in a particular position in order to maintain the current position of the tooth.

[0196] A method 400 of creating an orthodontic appliance using the photopolymerizable compositions of the present disclosure can include general steps as outlined in FIG. 4. Individual aspects of the process are discussed in further detail below. The process includes generating a treatment plan for repositioning a patient’s teeth. Briefly, a treatment plan can include obtaining data representing an initial arrangement of the patient’s teeth (Step 410), which typically includes obtaining an impression or scan of the patient’s teeth prior to the onset of treatment. The treatment plan will also include identifying a final or target arrangement of the patient’s anterior and posterior teeth as desired (Step 420), as well as a plurality of planned successive or intermediary tooth arrangements for moving at least the anterior teeth along a treatment path from the initial arrangement toward the selected final or target arrangement (Step 430). One or more appliances can be virtually designed based on the treatment plan (Step 440), and image data representing the appliance designs can exported in STL format, or in any other suitable computer processable format, to an additive manufacturing device (e.g., a 3D printer system) (Step 450). An appliance can be manufactured using a photopolymerizable composition of the present disclosure retained in the additive manufacturing device (Step 460). [0197] In some embodiments, a (e.g., non-transitory) machine-readable medium is employed in additive manufacturing of articles according to at least certain aspects of the present disclosure. Data is typically stored on the machine -readable medium. The data represents a three-dimensional model of an article, which can be accessed by at least one computer processor interfacing with additive manufacturing equipment (e.g., a 3D printer, a manufacturing device, etc.). The data is used to cause the additive manufacturing equipment to create an article comprising a reaction product of a photopolymerizable composition, the photopolymerizable composition includes a blend of: 30-60 wt.% of at least one (meth)acrylate reactive diluent, a photoinitiator, and 30-60 wt.% of a polymerization reaction product of components comprising a urea functional component or an acrylamide functional component. A cured homopolymer of at least one (meth)acrylate reactive diluent has a T_g of 50°C or greater. The polymerized reaction product of the photopolymerizable composition has a shape of the orthodontic article. The details of the photopolymerizable composition are as described above.

[0198] Data representing an article may be generated using computer modeling, such as computer aided design (CAD) data. Image data representing the (e.g., polymeric) article design can be exported in STL format, or in any other suitable computer processable format, to the additive manufacturing equipment. Scanning methods to scan a three-dimensional object may also be employed to create the data representing the article. One exemplary technique for acquiring the data is digital scanning. Any other suitable scanning technique may be used for scanning an article, including X-ray radiography, laser scanning, computed tomography (CT), magnetic resonance imaging (MRI), and ultrasound imaging. Other possible scanning methods are described, e.g., in U.S. Patent Application Publication No. 2007/0031791 (Cinader, Jr., et al.). The initial digital data set, which may include both raw data from scanning operations and data representing articles derived from the raw data, can be processed to segment an article design from any surrounding structures (e.g., a support for the article). In select embodiments, scanning techniques may include, for example, scanning a patient’s mouth to customize an orthodontic article for the patient. Often, machine -readable media are provided as part of a computing device. The computing device may have one or more processors, volatile memory (RAM), a device for reading machine -readable media, and input/output devices, such as a display, a keyboard, and a pointing device. Further, a computing device may also include other software, firmware, or combinations thereof, such as an operating system and other application software. A computing device may be, for example, a workstation, a laptop, a personal digital assistant (PDA), a server, a mainframe or any other general -purpose or application-specific computing device. A computing device may read executable software instructions from a computer-readable medium (such as a hard drive, a CD-ROM, or a computer memory), or may receive instructions from another source logically connected to computer, such as another networked computer. Referring to FIG. 10, a computing device 1000 often includes an internal processor 1080, a display 1100 (e.g., a monitor), and one or more input devices such as a keyboard 1140 and a mouse 1120. In FIG. 10, an aligner article 1130 is shown on the display 1100. [0199] Referring to FIG. 6, in certain embodiments, the present disclosure provides a system 600. The system 600 comprises a display 620 that displays a 3D model 610 of an article (e.g., an aligner 1130 as shown on the display 1100 of FIG. 10); and one or more processors 630 that, in response to the 3D model 610 selected by a user, cause a 3D printer / additive manufacturing device 650 to create a physical object of the article 660. Often, an input device 640 (e.g., keyboard and/or mouse) is employed with the display 620 and the at least one processor 630, particularly for the user to select the 3D model 610. The article 660 comprises a reaction product of a photopolymerizable composition, the photopolymerizable composition includes a blend of: 30-60 wt.% of at least one (meth)acrylate reactive diluent and 30-60 wt.% of a polymerization reaction product of components comprising a urea functional component or an acrylamide functional component, wherein the photopolymerizable composition exhibits a dynamic viscosity of less than 5000 centipoises (cP), when measured by a cone and plate rheometer at a temperature of 20 degrees Celsius and at a shear rate of 1 1/s. The polymerized reaction product of the photopolymerizable composition has a shape of the orthodontic article. The details of the photopolymerizable composition are as described above. [0200] Referring to FIG. 7, a processor 720 (or more than one processor) is in communication with each of a machine -readable medium 710 (e.g., a non-transitory medium), a 3D printer / additive manufacturing device 740, and optionally a display 730 for viewing by a user. The 3D printer / additive manufacturing device 740 is configured to make one or more articles 750 based on instructions from the processor 720 providing data representing a 3D model of the article 750 (e.g., an aligner article 1130 as shown on the display 1100 of FIG. 10) from the machine-readable medium 710. Referring to FIG. 8, for example and without limitation, an additive manufacturing method comprises retrieving 810, from a (e.g., non-transitory) machine-readable medium, data representing a 3D model of an article according to at least one embodiment of the present disclosure. The method further includes executing 820, by one or more processors, an additive manufacturing application interfacing with a manufacturing device using the data; and generating 830, by the manufacturing device, a physical object of the article. The additive manufacturing equipment can selectively cure a photopolymerizable composition to form an article. The article comprises a reaction product of a photopolymerizable composition, the photopolymerizable composition includes a blend of: 30-60 wt.% of at least one (meth)acrylate reactive diluent, a photoinitiator, and 30-60 wt.% of a polymerization reaction product of components comprising a urea functional component or an acrylamide functional component. A cured homopolymer of at least one (meth)acrylate reactive diluent has a T_g of 50°C or greater. A cured homopolymer of at least one monofunctional (meth)acrylate monomer has a T_g of 30 degrees Celsius (°C) or greater. The polymerized reaction product of the photopolymerizable composition has a shape of the orthodontic article. The details of the photopolymerizable composition are as described above. One or more various optional post processing steps 840 may be undertaken. Typically, remaining unpolymerized photopolymerizable component may be cured. The article comprises an orthodontic article.

[0201] Additionally, referring to FIG. 9, a method of making an article comprises receiving 910, by a manufacturing device having one or more processors, a digital object comprising data specifying a plurality of layers of an orthodontic article; and generating 920, with the manufacturing device by an additive manufacturing process, the article based on the digital object. Again, the article may undergo one or more steps of post-processing.

Select Embodiments of the Disclosure

[0202] Embodiment 1 is a photopolymerizable composition. The photopolymerizable composition includes 30 to 60 wt.% of at least one (meth) acrylate reactive diluent, a photoinitiator, and 30-60 wt.% of a polymerization reaction product of components comprising a urea functional component or an acrylamide functional component. The photopolymerizable composition exhibits a dynamic viscosity of less than 5000 centipoises (cP), when measured by a cone and plate rheometer at a temperature of 20 degrees Celsius and at a shear rate of 1 1/s.

[0203] Embodiment 2 is a photopolymerizable composition of embodiment 1, wherein photopolymerizable composition exhibits a dynamic viscosity of less than 2000 cP at 40 °C.

[0204] Embodiment 3 is a photopolymerizable composition of embodiment 1 or embodiment 2, wherein photopolymerizable composition exhibits a dynamic viscosity of less than 400 cP at 60 °C. [0205] Embodiment 4 is a photopolymerizable composition of embodiments 1 to 3, wherein the photopolymerizable composition comprises 5% by weight or less of a urethane component.

[0206] Embodiment 5 is a photopolymerizable composition of embodiments 1 to 4, wherein the photopolymerizable composition comprises 45-60 wt.% of the at least one (meth)acrylate reactive diluent, based on a total weight of the photopolymerizable composition, 30-50 wt.% of a first polymerization reaction product of components, based on the total weight of the photopolymerizable composition, optionally up to 10 wt.% of a crosslinker having a glass transition temperature (T_g) of 50°C or greater, and optionally up to 12 wt.% of a second polymerization reaction product of components, based on the total weight of the photopolymerizable composition. The first polymerization reaction product comprises a first polyether polyamine, and an ethylenically- unsaturated isocyanate functional monomer. The second polymerization reaction product of components comprises a second polyether polyamine, and an ethylenically-unsaturated isocyanate functional monomer. [0207] Embodiment 6 is a photopolymerizable composition of embodiments 1 to 5, wherein the photopolymerizable composition comprises 40-50 wt.% of the first polymerization reaction product of components and the composition contains no more than 5 wt.% of the second polymerization reaction product of components.

[0208] Embodiment 7 is a photopolymerizable composition of embodiments 1 to 6, wherein the photopolymerizable composition comprises 40-50 wt.% of the first polymerization reaction product of components, a crosslinker, and the composition contains no more than 5 wt.% of the second polymerization reaction product of components.

[0209] Embodiment 8 is a photopolymerizable composition of embodiments 1 to 7, wherein the photopolymerizable composition comprises 30-40 wt.% of the first polymerization reaction product of components, then the composition includes at least one of 55-60 wt.% of the (meth)acrylate reactive diluent, 5-12 wt.% of the second polymerization reaction product of components, 5-10 wt.% of the crosslinker, or 1-10 wt.% of methacrylic acid.

[0210] Embodiment 9 is a photopolymerizable composition of embodiments 1 to 8, wherein the photopolymerizable composition comprises 30-40 wt.% of the first polymerization reaction product of components, and 55-60 wt.% of the (meth) acrylate reactive diluent.

[0211] Embodiment 10 is a photopolymerizable composition of embodiments 1 to 9, wherein the photopolymerizable composition comprises 30-40 wt.% of the first polymerization reaction product of components, 55-60 wt.% of the (meth) acrylate reactive diluent, 5-12 wt.% of the second polymerization reaction product of components, and 5-10 wt.% of the crosslinker.

[0212] Embodiment 11 is a photopolymerizable composition of embodiments 1 to 10, wherein the photopolymerizable composition comprises 30-40 wt.% of the first polymerization reaction product of components, 55-60 wt.% of the (meth)acrylate reactive diluent, and 1-10 wt.% of methacrylic acid.

[0213] Embodiment 12 is a photopolymerizable composition of embodiments 1 to 11, wherein the photopolymerizable composition comprises 30-40 wt.% of the first polymerization reaction product of components, 55-60 wt.% of the (meth)acrylate reactive diluent, and 5-12 wt.% of the second polymerization reaction product of components.

[0214] Embodiment 13 is a photopolymerizable composition of embodiments 1 to 12, wherein the photopolymerizable composition comprises 40-50 wt.% of the first polymerization reaction product of components, 55-60 wt.% of the (meth) acrylate reactive diluent, 5-12 wt.% of the second polymerization reaction product of components, and 5-10 wt.% of the crosslinker.

[0215] Embodiment 14 is a photopolymerizable composition of embodiments 1 to 13, wherein the photopolymerizable composition comprises 30-40 wt.% of the first polymerization reaction product of components, 55-60 wt.% of the (meth) acrylate reactive diluent, 5-12 wt.% of the second polymerization reaction product of components, and 1-10 wt.% of methacrylic acid.

[0216] Embodiment 15 is a photopolymerizable composition of embodiments 5 to 14, wherein the first polymerization reaction product of components comprises a polyether polyamine which is a polyether triamine having a weight average molecular weight (M„) of 300 to 6,500 grams per mole (g/mol), as determined by gel permeation chromatography.

[0217] Embodiment 16 is a photopolymerizable composition of embodiment 15, wherein the poly ether poly amine is a poly ether triamine having a structure of Formula II:

Formula II wherein n is 1 to 10; x is 1 to 84; y is 1 to 84; and z is 1 to 84.

[0218] Embodiment 17 is a photopolymerizable composition of embodiments 5 to 14, wherein the first polymerization reaction product of components comprises a polyether polyamine which is a polyether diamine having a M_n of 200 to 4,000 g/mol, as determined by gel permeation chromatography.

[0219] Embodiment 18 is a photopolymerizable composition of embodiment 17, wherein the polyether polyamine is a polyether diamine having a structure of Formula I:

Formula I wherein x is 4 to 90.

[0220] Embodiment 19 is a photopolymerizable composition of embodiments 1 to 18, wherein the first polymerization reaction product of components is present in an amount of 40-50 wt.%, based on the total weight of the photopolymerizable composition.

[0221] Embodiment 20 is a photopolymerizable composition of embodiments 1 to 19, wherein the first polymerization reaction product of components is present in an amount of 30 wt.% to less than 40 wt.%, based on the total weight of the photopolymerizable composition.

[0222] Embodiment 21 is a photopolymerizable composition of embodiments 1 to 20, wherein the (meth)acrylate reactive diluent is present in an amount of 55-60 wt.%, based on the total weight of the photopolymerizable composition. [0223] Embodiment 22 is a photopolymerizable composition of embodiments 20 to 21, wherein the second polymerization reaction product of components is present in an amount of 5-12 wt.%, based on the total weight of the photopolymerizable composition.

[0224] Embodiment 23 is a photopolymerizable composition of embodiments 20 to 22, wherein the crosslinker is present in an amount of 5-10 wt.%, based on the total weight of the photopolymerizable composition.

[0225] Embodiment 24 is a photopolymerizable composition of embodiments 1 to 4, wherein the photopolymerizable composition comprises 30-50 wt.% of the (meth)acrylate reactive diluent, and 40-60 wt.% of the polymerization reaction product of components. The polymerization reaction product of components comprises a polymeric diol and an azlactone.

[0226] Embodiment 25 is a photopolymerizable composition of embodiment 24, wherein the azlactone comprises 2-vinyl-4,4-dimethylazlactone.

[0227] Embodiment 26 is a photopolymerizable composition of embodiments 23 to 25, wherein the photopolymerizable composition further comprises a crosslinker.

[0228] Embodiment 27 is a photopolymerizable composition of embodiment 26, wherein the crosslinker comprises a polymerized reaction product of a polyamine and an azlactone.

[0229] Embodiment 28 is a photopolymerizable composition of embodiments 24 to 27, wherein the polymeric diol has a number average molecular weight (M_n) of 200 to 5,000 grams per mole (g/mol) or 400 to 3,000 g/mol, as determined by gel permeation chromatography.

[0230] Embodiment 29 is a photopolymerizable composition of embodiments 24 to 28, wherein the polymeric diol comprises a polyester diol, a polycarbonate diol, a polyether diol, a polyolefin diol, or combinations thereof.

[0231] Embodiment 30 is a photopolymerizable composition of embodiments 24 to 29, wherein the polymeric diol comprises a polycarbonate diol.

[0232] Embodiment 31 is a photopolymerizable composition of embodiments 24 to 30, wherein the polymeric diol comprises a polycarbonate diol of Formula III

H(O-Ri-O-C(=O))_m-O-R₂-OH

Formula III wherein each of Ri in each (O-Ri-O-C(=O)) repeat unit, and R₂, are independently an aliphatic, cycloaliphatic, or aliphatic/cycloaliphatic alkylene group and an average number of carbon atoms in a combination of all the Ri and R₂ groups is 4 to 10, and m is (an integer of) 2 to 23.

[0233] Embodiment 32 is a photopolymerizable composition of embodiments 24 to 31 , wherein the photopolymerizable composition further comprises an azlactone.

[0234] Embodiment 33 is a photopolymerizable composition of embodiments 1 to 32, wherein the (meth)acrylate reactive diluent comprises at least one of isobornyl methacrylate, isobornyl acrylate, methyl methacrylate, tertiobutyl cyclohexyl methacrylate, 3,3,5 trimethylcyclohexyl methacrylate, or tricyclodecanedimethanol diacrylate.

[0235] Embodiment 34 is a photopolymerizable composition of embodiments 1 to 33, wherein the (meth)acrylate reactive diluent is isobornyl methacrylate.

[0236] Embodiment 35 is a photopolymerizable composition of embodiments 1 to 34, wherein the photopolymerizable composition further comprises at least one of methacrylic acid, an antioxidant, or a UV absorber.

[0237] Embodiment 36 is an orthodontic article. The orthodontic article includes a polymerized reaction product of a photopolymerizable composition. The photopolymerizable includes 45-60 wt.% of the at least one (meth)acrylate reactive diluent, based on a total weight of the photopolymerizable composition, 30-50 wt.% of a first polymerization reaction product of components, based on the total weight of the photopolymerizable composition, optionally up to 10 wt.% of a crosslinker having a glass transition temperature (T_g) of 50°C or greater, and optionally up to 12 wt.% of a second polymerization reaction product of components, based on the total weight of the photopolymerizable composition. The first polymerization reaction product comprises a first polyether polyamine, and an ethylenically-unsaturated isocyanate functional monomer. The second polymerization reaction product of components comprises a second polyether polyamine, and an ethylenically-unsaturated isocyanate functional monomer. The polymerized reaction product has a T_g of 50°C or greater.

[0238] Embodiment 37 is an orthodontic article of embodiment 36, wherein the photopolymerizable composition comprises 40-50 wt.% of the first polymerization reaction product of components and the composition contains no more than 5 wt.% of the second polymerization reaction product of components.

[0239] Embodiment 38 is an orthodontic article of embodiments 36 to 37, wherein the photopolymerizable composition comprises 40-50 wt.% of the first polymerization reaction product of components, a crosslinker, and the composition contains no more than 5 wt.% of the second polymerization reaction product of components.

[0240] Embodiment 39 is an orthodontic article of embodiments 36 to 38, wherein the photopolymerizable composition comprises 30-40 wt.% of the first polymerization reaction product of components, then the composition includes at least one of 55-60 wt.% of the (meth)acrylate reactive diluent, 5-12 wt.% of the second polymerization reaction product of components, 5-10 wt.% of the crosslinker, or 1-10 wt.% of methacrylic acid.

[0241] Embodiment 40 is an orthodontic article of embodiments 36 to 39, wherein the photopolymerizable composition comprises 30-40 wt.% of the first polymerization reaction product of components, and 55-60 wt.% of the (meth) acrylate reactive diluent. [0242] Embodiment 41 is an orthodontic article of embodiments 36 to 40, wherein the photopolymerizable composition comprises 30-40 wt.% of the first polymerization reaction product of components, 55-60 wt.% of the (meth) acrylate reactive diluent, 5-12 wt.% of the second polymerization reaction product of components, and 5-10 wt.% of the crosslinker.

[0243] Embodiment 42 is an orthodontic article of embodiments 36 to 41, wherein the photopolymerizable composition comprises 30-40 wt.% of the first polymerization reaction product of components, 55-60 wt.% of the (meth)acrylate reactive diluent, and 1-10 wt.% of methacrylic acid.

[0244] Embodiment 43 is an orthodontic article of embodiments 36 to 42, wherein the photopolymerizable composition comprises 30-40 wt.% of the first polymerization reaction product of components, 55-60 wt.% of the (meth)acrylate reactive diluent, and 5-12 wt.% of the second polymerization reaction product of components.

[0245] Embodiment 44 is an orthodontic article of embodiments 36 to 43, wherein the photopolymerizable composition comprises 30-40 wt.% of the first polymerization reaction product of components, 45-60 wt.% of the (meth)acrylate reactive diluent, a photoinitiator, 5-12 wt.% of the second polymerization reaction product of components, and 5-10 wt.% of the crosslinker.

[0246] Embodiment 45 is an orthodontic article of embodiments 36 to 44, wherein the photopolymerizable composition comprises 30-40 wt.% of the first polymerization reaction product of components, 55-60 wt.% of the (meth) acrylate reactive diluent, 5-12 wt.% of the second polymerization reaction product of components, and 1-10 wt.% of methacrylic acid.

[0247] Embodiment 46 is an orthodontic article of embodiments 36 to 45, wherein the first polymerization reaction product of components comprises a polyether polyamine which is a polyether triamine having a eight average molecular weight (M„) of 300 to 6,500 grams per mole (g/mol), as determined by gel permeation chromatography.

[0248] Embodiment 47 is an orthodontic article of embodiment 46, wherein the poly ether poly amine is a polyether triamine having a structure of Formula II:

Formula II wherein n is 1 to 10; x is 1 to 84; y is 1 to 84; and z is 1 to 84.

[0249] Embodiment 48 is an orthodontic article of embodiments 36 to 45, wherein the first polymerization reaction product of components comprises a polyether polyamine which is a polyether diamine having a M_n of 200 to 4,000 g/mol, as determined by gel permeation chromatography.

[0250] Embodiment 49 is an orthodontic article of embodiment48, wherein the poly ether poly amine is a polyether diamine having a structure of Formula I:

Formula I wherein x is 4 to 90.

[0251] Embodiment 50 is an orthodontic article of embodiments 36 to 49, wherein the first polymerization reaction product of components is present in an amount of 40-50 wt.%, based on the total weight of the photopolymerizable composition.

[0252] Embodiment 51 is an orthodontic article of embodiments 36 to 50, wherein the first polymerization reaction product of components is present in an amount of 30 wt.% to less than 40 wt.%, based on the total weight of the photopolymerizable composition.

[0253] Embodiment 52 is an orthodontic article of embodiments 36 to 51, wherein the (meth)acrylate reactive diluent is present in an amount of 55-60 wt.%, based on the total weight of the photopolymerizable composition.

[0254] Embodiment 53 is an orthodontic article of embodiments 36 to 52, wherein the second polymerization reaction product of components is present in an amount of 5-12 wt.%, based on the total weight of the photopolymerizable composition.

[0255] Embodiment 54 is an orthodontic article of embodiments 36 to 53, wherein the crosslinker is present in an amount of 5-10 wt.%, based on the total weight of the photopolymerizable composition.

[0256] Embodiment 55 is an orthodontic article of embodiments 36 to 54, wherein the polymerized reaction product of a photopolymerizable composition exhibits each of a tensile stress at break of 15 megapascals (MPa) or greater, a Young’s modulus of 300 MPa or greater, and a tensile strain at break of 65% or greater.

[0257] Embodiment 56 is an orthodontic article. The orthodontic article is a polymerized reaction product of a photopolymerizable composition. The photopolymerizable composition comprises SOSO wt.% of the (meth) acrylate reactive diluent, and 40-60 wt.% of the polymerization reaction product of components. The polymerization reaction product of components comprises a polymeric diol and an azlactone. The polymerized reaction product of the photopolymerizable composition has a T_g of 50 °C or greater, more preferably above 80 °C or 90 °C. [0258] Embodiment 57 is an orthodontic article of embodiment 56, wherein the azlactone comprises 2-vinyl-4,4-dimethylazlactone.

[0259] Embodiment 58 is an orthodontic article of embodiments 56 to 57, wherein the photopolymerizable composition further comprises a crosslinker.

[0260] Embodiment 59 is an orthodontic article of embodiment 58, wherein the crosslinker comprises a polymerized reaction product of a poly amine and an azlactone.

[0261] Embodiment 60 is an orthodontic article of embodiments 56 to 59, wherein the polymeric diol has a number average molecular weight (M_n) of 200 to 5,000 grams per mole (g/mol) or 400 to 3,000 g/mol, as determined by gel permeation chromatography.

[0262] Embodiment 61 is an orthodontic article of embodiments 56 to 60, wherein the polymeric diol comprises a polyester diol, a polycarbonate diol, a polyether diol, a polyolefin diol, or combinations thereof.

[0263] Embodiment 62 is an orthodontic article of embodiments 56 to 61, wherein the polymeric diol comprises a polycarbonate diol.

[0264] Embodiment 63 is an orthodontic article of embodiments 56 to 62, wherein the polymeric diol comprises a polycarbonate diol of Formula III

H(O-Ri-O-C(=O))_m-O-R₂-OH

Formula III wherein each of Ri in each (O-Ri-O-C(=O)) repeat unit, and R₂, are independently an aliphatic, cycloaliphatic, or aliphatic/cycloaliphatic alkylene group and an average number of carbon atoms in a combination of all the Ri and R₂ groups is 4 to 10, and m is (an integer of) 2 to 23.

[0265] Embodiment 64 is an orthodontic article of embodiments 56 to 63, wherein the photopolymerizable composition further comprises an azlactone.

[0266] Embodiment 65 is an orthodontic article of embodiments 56 to 64, wherein the photopolymerizable composition further comprises 2-vinyl-4,4-dimethylazlactone (VDM).

[0267] Embodiment 66 is an orthodontic article of embodiments 56 to 65, wherein the (meth)acrylate reactive diluent comprises at least one of isobornyl methacrylate, isobornyl acrylate, methyl methacrylate, tertiobutyl cyclohexyl methacrylate, 3,3,5 trimethylcyclohexyl methacrylate, or tricyclodecanedimethanol diacrylate.

[0268] Embodiment 67 is an orthodontic article of embodiments 36 to 66, wherein the photopolymerizable composition further comprises at least one of methacrylic acid, an antioxidant, or a UV absorber.

[0269] Embodiment 68 is an orthodontic article of embodiments 56 to 67, wherein the polymerized reaction product of the photopolymerizable composition exhibits each of a tensile stress at break of 15 megapascals (MPa) or greater and a tensile strain at break of 65% or greater. [0270] Embodiment 69 is an orthodontic article of embodiments 56 to 68, wherein the polymerized reaction product of the photopolymerizable composition exhibits a Young’s modulus of 175 MPa or greater.

[0271] Embodiment 70 is an orthodontic article of embodiments 56 to 69, wherein the polymerized reaction product of the photopolymerizable composition exhibits a water uptake of no more than 1.5 percent by weight after soaking in deionized water at a temperature of 20-25 degrees Celsius for 72 hours.

[0272] Embodiment 71 is an orthodontic article of embodiments 56 to 70, wherein the polymerized reaction product of a photopolymerizable composition exhibits a peak loss modulus below 20 °C and a tan delta peak >70 °C.

[0273] Embodiment 72 is a method of making an orthodontic article. The method includes a) obtaining a photopolymerizable composition; b) selectively curing the photopolymerizable composition; and c) repeating steps a) and b) to form multiple layers and create the orthodontic article. The photopolymerizable composition includes a composition according to embodiments herein.

[0274] Embodiment 73 is a method of embodiment 72, wherein the method optionally includes curing unpolymerized photopolymerizable composition remaining after step (c).

[0275] Embodiment 74 is a method of embodiment 73 or embodiment 74, wherein the method further optionally includes removing at least a portion of the unpolymerized photopolymerizable composition remaining after step (c).

[0276] Embodiment 75 is the method of embodiments 72 to 74, wherein the photopolymerizable composition is cured using actinic radiation including UV radiation, e-beam radiation, visible radiation, or a combination thereof.

[0277] Embodiment 76 is the method of embodiment 75, wherein the actinic radiation is directed through a wall of a container holding the photopolymerizable composition.

[0278] Embodiment 77 is the method of embodiments 75 or embodiment 76, wherein 90% or greater of the actinic radiation is absorbed over a distance of 150 micrometers of the photopolymerizable composition.

[0279] Embodiment 78 is the method of any of embodiments 72 to 77, wherein the photopolymerizable composition is cured through a floor of a container holding the photopolymerizable composition.

[0280] Embodiment 79 is the method of any of embodiments 72 to 78, further including post curing the orthodontic article using actinic radiation.

[0281] Embodiment 80 is the method of any of embodiments 72 to 79, wherein the method includes vat polymerization of the photopolymerizable composition. [0282] Embodiment 81 is the method of any of embodiments 72 to 80, further including subjecting the orthodontic article to a heat treatment.

[0283] Embodiment 82 is the method of any of embodiments 72 to 81, wherein the orthodontic article exhibits each of a tensile stress at break of 15 megapascals (MPa) or greater, a Young’s modulus of 300 MPa or greater, and a tensile strain at break of 65% or greater.

[0284] Embodiment 83 is the method of any of embodiments 72 to 82, wherein the orthodontic article exhibits a Young’s modulus of 175 MPa or greater.

[0285] Embodiment 84 is the method of any of embodiments 72 to 83, wherein the orthodontic article exhibits a water uptake of no more than 1.5 percent by weight after soaking in deionized water at a temperature of 20-25 degrees Celsius for 72 hours.

[0286] Embodiment 85 is the method of any of embodiments 72 to 84, wherein the polymerized reaction product of a photopolymerizable composition exhibits a peak loss modulus below 20 °C and a tan delta peak >70 °C.

[0287] Embodiment 86 is the method of any of embodiments 72 to 85, wherein the orthodontic article contains 1.5 wt.% or less extractable components.

[0288] Embodiment 87 is the method of any of embodiments 72 to 86, wherein the orthodontic article includes a dental restorative tool, a mold, a dental tray, a retainer, or an aligner.

[0289] Embodiment 88 is the method of any of embodiments 72 to 87, wherein the orthodontic article includes a dental restorative tool, or a mold.

[0290] Embodiment 89 is a method including a) receiving, by a manufacturing device having one or more processors, a digital object comprising data specifying a plurality of layers of an orthodontic article; and b) generating, with the manufacturing device by an additive manufacturing process, the orthodontic article based on the digital object. The orthodontic article includes a reaction product of a photopolymerizable composition according to embodiments herein. The polymerized reaction product of the photopolymerizable composition has a shape of the orthodontic article.

[0291] Embodiment 90 is a system including a) a display that displays a 3D model of an orthodontic article; and b) one or more processors that, in response to the 3D model selected by a user, cause a 3D printer to create a physical object of an orthodontic article. The orthodontic article includes a reaction product of a photopolymerizable composition according to embodiments herein. The polymerized reaction product of the photopolymerizable composition has a shape of the orthodontic article.

[0292] Embodiment 91 is a dental restorative tool or mold comprising a polymerized reaction product of a photopolymerizable composition according to embodiments herein.

[0293] Embodiment 92 is a non-transitory machine readable medium comprising data representing a three-dimensional model of an orthodontic article, when accessed by one or more processors interfacing with a 3D printer, causes the 3D printer to create an orthodontic article including a reaction product of a photopolymerizable composition according to embodiments herein. The polymerized reaction product of the photopolymerizable composition has a shape of the orthodontic article.

[0294] Embodiment 93 is a method including a) retrieving from a non-transitory machine readable medium, data representing a 3D model of an article; b) executing, by one or more processors, a 3D printing application interfacing with a manufacturing device using the data; and c) generating, by the manufacturing device, a physical object of the orthodontic article. The orthodontic article includes a reaction product of a photopolymerizable composition according to embodiments herein. The polymerized reaction product of the photopolymerizable composition has a shape of the orthodontic article.

EXAMPLES

[0295] Objects and advantages of this disclosure are further illustrated by the following examples, but the particular materials and amounts thereof recited in these examples, as well as other conditions and details, should not be construed to unduly limit this disclosure.

Materials

[0296] Unless otherwise noted, all parts, percentages, ratios, etc. in the examples and the rest of the specification are expressed by weight. The Materials Table 1 below lists materials used in the examples and their sources.

Materials Table 1

PREPARATORY EXAMPLES

Synthesis of urea functional component

Synthesis of polypropylene glycol based polyurea (meth)acrylate polymers

[0297] Urea functional components of the composition were prepared by the methods explained herein as represented in Schemes 1 and 2. Scheme 1 illustrate the synthesis of polymerized reaction product from polyether diamine and an isocyanate monomer, wherein the polyether diamine and the isocyanate monomer were taken in mole ratio of 1:2. Similarly, Scheme 2 illustrate the synthesis of polymerized reaction product from polyether triamine and an isocyanate monomer, wherein poly ether triamine and an isocyanate monomer were taken in mole ratio of 1:3.

Scheme 2

Preparation of urea methacrylate T3000 (PEI)

[0298] Urea methacrylate T3000 (PEI) was prepared by the synthetic method as depicted in Scheme 2 above. To a two-neck round-bottom flask was added Jeffamine T3000 (30.00 g, 10.0 mmol). The flask was equipped with an overhead stirrer and a dropping funnel. The round-bottom flask was then submerged in a room-temperature water bath. IEM (neat, 4.75 g, 30.06 mmol) was added to dropwise to the flask through a under stirring. After addition of IEM, the reaction solution was stirred for 30 minutes (min). 'H NMR analysis on the obtained product indicated the amine completely reacted to form PEI. PEI was used without further purification. [0299] Similarly the samples in Table 2 below were prepared by method described above, illustrated by Scheme 1 or 2, using amounts and types of materials indicated herein. PE3 to PE6 were prepared by Scheme 1; and PE2 and PE7 were prepared by Scheme 2.

Table 2. Preparative Examples of Polypropylene Glycol Based Polyurea (Meth)Acrylates

Synthesis of acrylamide functional component

Synthesis of Acrylamide-Functional Polymer from C-2050 diol and VDM in solvent (PE8)

Scheme 3

[0300] Kuraray C-2050 diol (50.1 g, 0.051 moles -OH), VDM (8.3 g, 0.0593 moles, 1.17 eq to OH), DBU (0.15 mL, 0.155 g, 0.02 eq to -OH), and 280 mL DCM were added to a round bottom flask equipped with magnetic stirrer. The flask was fitted with a reflux condenser, dry air inlet, and bubbler and the reaction mixture was heated to reflux. The crude reaction was monitored by 'H NMR using the resonances corresponding to the methylene polymer-CHz-OH end group and found to be incomplete after 24 hours (h). At this time, additional DBU (0.15 mL, 0.155g, 0.02 eq to -OH) was added. The reaction mixture was then heated for additional 4 h, and the polymer was found to be fully end group functionalized by¹ H NMR analysis. The solvent was removed under vacuum to yield neat acrylamide functional polymer (PE8).

Synthesis of Acrylamide-Functional Polymer from C-2050 diol and VDM neat (PE9)

Scheme 4

[0301] Kuraray C-2050 diol (136 g, 0.139 moles -OH), VDM (22.4 g, 0.161 moles, 1.16 eq to OH), DBU (0.5 mL, 0.51 g, 0.0033 moles, 0.024 eq relative to -OH), and 100 mL DCM were added to a 250 mL round bottom flask equipped with magnetic stirrer. The flask was fitted with a reflux condenser, dry air inlet, and bubbler and the reaction mixture was heated to 80 °C. The crude reaction was monitored by¹ H NMR using the resonances corresponding to the methylene polymer-CHz-OH end group and found to be >95% complete after 4 h and thus the acrylamide functional polymer (PE9) was obtained. At this time the reaction mixture was diluted with IBOMA (111 g, target 41 wt.%) and this mixture was used to prepare resin compositions.

Synthesis of Crosslinkers

Synthesis of Acrylamide-Crosslinkers from Polyamine and VDM (PE10)

Scheme 5

[0302] Baxxodur EC301 (5.0 g, 0.043 moles -NH2), VDM 6.35g, 0.045moles, 1.05 eq to NH2), were added to a 3 -neck round bottom flask. The flask was fitted with an overhead stirrer, dry air inlet/bubbler, and thermocouple and the reaction mixture was heated to 80 °C. The crude reaction was monitored by¹ H NMR using the resonances corresponding to the methylene polymer-CHi-NHj end group and found to be incomplete after 24 h. At this time, additional DBU (0.15 mL, 0.155 g, 0.02 eq to -OH) was added. The reaction mixture was then heated for additional 4 h, and the polymer was found to be >95% end group functionalized by 'H NMR, and thereby resulting in PE10 crosslinker.

Synthesis of Succinic anhydride-derived amide-methacrylates

Synthesis of C-2050-amide-methacrylate using Succinic Anhydride (PE11)

[0303] 10.0 g of C-2050 diol taken in a round bottom flask equipped with an overhead stirrer with 10.0 g of IBOMA as a diluent afforded a viscous transparent solution. To this solution 0.98 g succinic anhydride and 0.0093 g (1%) p-toluene sulfonic acid were added. The reaction mixture was then heated at 65 °C and stirred overnight. Small amount of succinic anhydride sublimed to the neck of the flask, and was removed after the solution was cooled to room temperature. The conversion was calculated based on the¹ H NMR spectrum of the final product using ratio of resonance from the terminal methylene groups derived from succinic anhydride in the product at 2.58-2.75 ppm to the resonance of unreacted succinic anhydride at 3.02 ppm. The reaction yield reached 95-98% overnight. Addition of one equivalent of hexylamine to the products quenched unreacted succinic anhydride. The disappearance of resonances of succinic anhydride in the¹ H NMR of final products confirmed the complete consumption of succinic anhydride and complete formation of the product polyol C2050-acid.

[0304] To synthesize the polyol C2050 amide-ester di-methacrylate, 10.5 g of the previous product (5 g eq of polyol C2050-acid) was added to a brown vial equipped with a stir bar. The vial was then heated at 60 °C with the stirring on. 0.69 g 2-isocyanatoethyl methacrylate (IEM) was added dropwise into the flask and the reaction was initiated. The viscosity of the reaction mixture dropped with the addition of IEM. After few minutes, bubbles were found to be formed and the viscosity of the reaction mixture slowly increased. The reaction was maintained at 60 °C overnight. The progress of the reaction was tracked by the disappearance of the resonance of IEM using¹ H NMR technique. The conversion reached >99% overnight and the excess IEM was quenched via the addition of one equivalent of hexylamine. The exact percentage of IBOMA and polyol C-2050-amide dimethacrylate were determined by thermal gravimetric analysis (TGA), where about 5 mg of the product were heated to 450 °C with a rate of 10 °C/min. The weight percentage of IBOMA was calculated based on the first weight loss percentage from the TGA curve and the weight percentage of polyol C-2050-amide di-methacrylate was based on the remaining weight loss percentage.

Synthesis of amide-methacrylate from Jeffamine T3000 and succinic anhydride (PE12)

[0305] Jeffamine T3000 (10.0 g) and succinic anhydride (1.0 g) were added to a brown vial equipped with a stir bar. The reaction mixture was then heated at 65 °C and stirred overnight. The conversion was calculated based on the 'H NMR spectrum of the final product using ratio of resonance from the terminal methylene groups derived from succinic anhydride in the product at 2.58-2.75 ppm to the resonance of unreacted succinic anhydride at 3.02 ppm. The reaction yield reached 95-98% overnight. Addition of one equivalent of hexylamine to the products quenched unreacted succinic anhydride. The disappearance of resonances of succinic anhydride in the¹ H NMR of final products confirmed the complete consumption of succinic anhydride and the formation of Jeffamine T3000-acid.

[0306] To synthesize the Jeffamine T3000 amide-ester di-methacrylate, 10.5 g of the previous product (5 g eq of Jeffamine T3000-acid) was added to a brown vial equipped with a stir bar. The vial was then heated at 60 °C under stirring. 0.69 g of 2-isocyanatoethyl methacrylate (IEM) was added dropwise into the flask which initiated the reaction. The viscosity of the reaction mixture dropped with the addition of IEM. After a few minutes, bubbles were found to be formed and the viscosity of the reactants slowly increased. The reaction mixture was then kept at 60 °C overnight. The progress of the reaction was tracked by the disappearance of the resonance of IEM using¹ H NMR technique. The conversion reached >99% overnight and the excess IEM was quenched via the addition of one equivalent of hexylamine.

General procedure for preparation of formulations/photopolymerizable compositions General procedure for preparation of urea-based compositions [0307] Compositions were prepared by weighting the components (indicated in Tables 3-7) in an amber jar, followed by rolling on a roller (OLDE MIDWAY PRO 18) at room temperature until fully mixed.

Table 3. Examples for Urea-based compositions (Amount in parts by weight)

Table 4. Examples for Urea-based compositions (Amount in parts by weight)

Table 5. Comparative Examples for Urea-based compositions (Amount in parts by weight)

Table 6. Comparative Examples for Urea-based compositions (Amount in parts by weight)

Table 7. Prophetic Examples for Urea-based compositions (Amount in parts by weight)

General procedure for preparation of acrylamide-based compositions

[0308] To prepare resins for casting, acrylamide -functional polymer, IBOMA, TPO, BHT, and Tinuvin 326 were added in a 10 oz brown bottle. To fully dissolve the solids and mix the resin, the bottle was capped and put on a tube roller at room temperature overnight before use. [0309] The same procedure was used to make all of the following resins, charging the appropriate quantities to prepare copolymers with the weight percentages of each monomer as indicated in Tables 8-9.

Table 8 Summary of Resin Compositions with VDM-derived Acrylamides (Amount in parts by weight)

Table 9. Comparative compositions from Succinic anhydride -derived amide-methacrylates (Amount in parts by weight)

[0310] To create samples for mechanical testing, the formulated composition (resin mixture) was then poured into a silicone dogbone mold (Type V mold of 1 mm thickness, ASTM D638-14) for tensile tests or a silicone rectangle mold (1 mm thickness, trimmed to 20 mm x 6 mm x 1 mm before use) for dynamic mechanical thermal analysis (DMTA) and dynamic mechanical analysis (DMA). The filled mold was placed between two glass plates and cured in an Asiga Pico Flash post-curing device for 120 seconds (s). The sample was demolded and cured on the backside for another 120 s in the same device. The sample was then cured in a Clearstone CA3200 controlled-atmosphere cure chamber equipped with 365, 385, and 405 nm LEDs, with nitrogen passing through the chamber. The samples were kept in an oven set at 100 °C for 1 h to remove any residual unreacted monomer.

General procedure for tensile testing

[0311] The tensile strength was determined by performing uniaxial extension of dogbone shaped specimens (ASTM D638-14 Type-V) at a displacement rate of 5 mm min¹ using Instron 6800 universal testing system (Instron, Norwood, MA) instrument equipped with a 5 kN load cell. The initial grip was 1 inch (2.5 cm) and the gauge was set to 1 inch (2.5 cm) as well. Six replicate samples for each composition were tested and the average value are reported. The data were analyzed and the ultimate tensile strength (tensile stress at break), tensile strain at break, and Young’s Modulus were determined using Bluehill Universal Software. The tensile test method was very similar to ASTM D638-14, however the Young’s modulus for all examples is taken by using cross head velocity to approximate strain rather than by using an extensometer.

Table 10. Measured Tensile Properties Urea-Based Resin Samples.

Table 11: Tensile results on Acrylamide-based cast samples (reported as average and std deviation of 5 bars)

General procedure for termination of loss modulus and tan delta using dynamic mechanical analysis

[0312] The storage modulus (E’), loss modulus (E”), tan delta, and glass transition temperature (T_g) were obtained from DMTA using DMA 850 instrument (TA instrument). The T_g is defined as the peak of tan delta and were summarized in Table 12 for the samples.

Table 12. Measured Physical Properties of Samples

General procedure for termination of stress relaxation and strain recovery using dynamic mechanical analysis

[0313] Stress relaxation and strain recovery were measured on selected samples on a DMA 850 (TA instrument) under 95% humidity and 37 °C. The samples were soaked in DI water overnight and were then equilibrated in the DMA chamber under 95% humidity at 37 °C with 0 N preload force for 5 min, then the stress relaxation was measured with 1 % strain on for 11 h followed by strain recovery measurement with 0 MPa stress for 1 h under 95% humidity at 37 °C. The results are summarized in Tables 13 and 14.

Table 13. Measured Stress Relaxation and Strain Recovery of Hydrated Urea-Based Samples.

Table 14: Stress Relaxation and strain recovery of hydrated acrylamide-based samples

Water Uptake Experiments on acrylamide samples

[0314] Water swelling experiments were conducted on crosslinked resin formulations EX-24, EX- 25, and EX-26. Resins were cured using the procedure described for preparing dog bone specimens for mechanical testing. For each resin composition, three specimens were weighed dry, then immersed in deionized water. The specimens were removed at 72 hours, patted dry, and reweighed.

The difference in weight divided by the original weight of the bar was taken to be the percent water uptake. Results are given in Table 15, below.

Table 15. Water uptake of resin at 72 hours (% weight gain).

General Procedure for Urea-based Additive Manufacturing Resin Preparation

[0315] Formulations were prepared by weighting the components (indicated in table 16) in an amber jar, followed by rolling on a roller (OLDE MIDWAY PRO 18) at room temperature until fully mixed.

Table 16. Example Additive Manufacturing Formulations (Amount in parts by weight)

General Procedure for Additive Manufacturing of Formulated Resins

[0316] Unless otherwise noted, all 3D-printed examples were manufactured on an Asiga Max X printer (Asiga USA, Anaheium Hills, CA) with a LED light source of 385nm, or a Rapidshape D90 (Rapid Shape GmbH, Heimsheim, Germany) using a 385nm LED light source. STL files of projects were loaded into the software and support structures were generated as needed. The following settings were used for the Asiga printer: Slice thickness = 100 pm, Burn-In Layers = 5, Separation Velocity = 1.5 mm/s, Slides per Layer = 1. For the Asiga Max X printer, the normal exposure time was determined via cure depth study for the printing resins, where a pool of resin was exposed to the printer light source for a period of time to cure a solid disk with a diameter of 0.5 cm. The exposure time ranged from 1 s to 15 s with an increment of 1 s. The cured disks were then washed with iPA to remove excess resin and allowed to dry. The thicknesses of cured disks were measured using a thickness Gauge (Mitutoyo 543, MiSUMi USA, Schaumburg, IL). The normal exposure time was determined where the cured thickness measured to be 100 pm, and the burn-in exposure time is double of the normal exposure time. A typical normal exposure time is 4.0 s and a typical burn-in exposure time is 8.0 s. The printing parameter for Rapidshape D90 were listed in table 17. After printing, the photopolymerized objects were then centrifuged in Beckman Coulter Avanti J- 20 XP (GMI, Ramsey, MN) with a spin speed of 800 rpm for 4 min, and then post-cured in a Clearstone CA3200 controlled-atmosphere cure chamber equipped with 365, 385, and 405 nm LEDs, with nitrogen passing through the chamber for 5 min. Finally, the printed objects were baked in a vacuum oven 1 h at 100 °C to remove any unreacted monomers.

Table 17. Printing Parameter for Rapidshape D90 Printer.

Measurement of Resin Viscosity

[0317] Resin viscosity of composition EX-23 was measured on a TA Instruments Discovery DHR rheometer equipped with 40 mm 2° upper cone and Peltier heating/cooling enabled on the bottom plate. The sample was equilibrated at temperature for a hold time of 1 minute, then frequency sweeps were conducted between 1/s and 100/s. Reported viscosity at each temperature is the best fit of the frequency sweep. Results are reported in Table 18, below.

Table 18. Zero Sheer Viscosity of Resin EX-23, EX8, and PE8 different temperatures

[0318] Gel permeation chromatography (GPC) method to determine weight average molecular weight (Mw)

[0319] The GPC equipment consisted of a 1260 Infinity II liquid chromatography system (comprised of isocratic pump, autosampler, column compartment and variable wavelength UV/vis detector) from Agilent Technologies (Santa Clara, CA) operated at a flow rate of 1.0 mL/minute. The SEC column set was comprised of two PLgel 5 pm MIXED-C (300 millimeter (mm) length x 7.5 mm internal diameter) and a PLgel 5 pm guard column (50 millimeter (mm) length x 7.5 mm internal diameter) all from Agilent Technologies. The detection consisted of a miniDAWN 3 angle Light Scattering detector and an OPTILAB differential refractive index detector, both from Wyatt Technology Corporation (Santa Barbara, CA). Data were collected and analyzed using software ASTRA version 8 from Wyatt Technology Corporation. The column compartment, UV/vis detector, and differential refractive index detector were set to 40 °C. The solvent and eluent (or mobile phase) consisted of tetrahydrofuran (stabilized with 250 parts per million of butylated hydroxytoluene) OMNISOLV grade from EMD Millipore Corporation, Burlington, MA. The relative molar mass data was determined from the DIR data and is reported relative to EasiCal PS-1 PL2010-0501 and PL2010-0505 polystyrene standards (PS) in the range of Mp = 580 to Mp = 2,403,000 g/mol from Agilent Technologies. The calibration curve was constructed in the ASTRA software, using all of the PS standards except for the Mp = 6,570,000, owing to it being outside the upper molecular weight resolution limits of the columns.

Table 19. Weight Average Molecular Weight (Mw) of Baxxodur EC301 and Jeffamine T5000

[0320] Baxxodur EC301 is reported to have a molecular weight of 230 g/mol and Jeffamine T5000 is reported to have a molecular weight of 5000. As indicated by the results of Table 19 above, a measured Mw may vary somewhat from manufacturer reported values.

[0321] All of the patents and patent applications mentioned above are hereby expressly incorporated by reference. The embodiments described above are illustrative of the present invention and other constructions are also possible. Accordingly, the present invention should not be deemed limited to the embodiments described in detail above and shown in the accompanying drawings, but instead only by a fair scope of the claims that follow along with their equivalents

Claims

What is claimed is:

1. A photopolymerizable composition comprising:

30-60 wt.% of at least one (meth)acrylate reactive diluent; a photoinitiator; and

30-60 wt.% of a polymerization reaction product of components comprising a urea functional component or an acrylamide functional component, wherein the photopolymerizable composition exhibits a dynamic viscosity of less than 5000 centipoises (cP), when measured by a cone and plate rheometer at a temperature of 20 degrees Celsius and at a shear rate of 1 1/s.

2. The photopolymerizable composition of claim 1, wherein the components comprise 5% by weight or less of a urethane component.

3. The photopolymerizable composition of claim 1 or claim 2, comprising:

45-60 wt.% of the at least one (meth)acrylate reactive diluent, based on a total weight of the photopolymerizable composition;

30-50 wt.% of a first polymerization reaction product of components, based on the total weight of the photopolymerizable composition, the components comprising: a first polyether polyamine; and an ethylenically-unsaturated isocyanate functional monomer; optionally up to 10 wt.% of a crosslinker having a glass transition temperature (T_g) of 50°C or greater; and optionally up to 12 wt.% of a second polymerization reaction product of components, based on the total weight of the photopolymerizable composition, the components comprising: a second poly ether polyamine; and an ethylenically-unsaturated isocyanate functional monomer; with the provisos that:

A) when the first polymerization reaction product of components is present in an amount of 40-50 wt.%, the composition contains no more than 5 wt.% of the second polymerization reaction product of components; and

B) when the first polymerization reaction product of components is present in an amount of 30 wt.% to less than 40 wt.%, the composition includes at least one of the following: i) 55-60 wt.% of the (meth)acrylate reactive diluent; ii) 5-12 wt.% ofthe second polymerization reaction product of components; iii) 5-10 wt.% ofthe crosslinker; or iv) 1-10 wt.% of methacrylic acid.

4. The photopolymerizable composition of claim 3, wherein the poly ether poly amine is a polyether triamine having a weight average molecular weight (M„) of 300 to 6,500 grams per mole (g/mol), as determined by gel permeation chromatography.

5. The photopolymerizable composition of any of claims 3 to 4, wherein the poly ether poly amine is a poly ether triamine having a structure of Formula II:

wherein n is 1 to 10; x is 1 to 84; y is 1 to 84; and z is 1 to 84.

6. The photopolymerizable composition of claim 3, wherein the poly ether poly amine is a polyether diamine having a Mn of 200 to 4,000 g/mol, as determined by gel permeation chromatography.

7. The photopolymerizable composition of any of claims 3 to 4 or 6, wherein the polyether poly amine is a poly ether diamine having a structure of Formula I:

wherein x is 4 to 90.

8. The photopolymerizable composition of any of claims 1 to 7, wherein the first polymerization reaction product of components is present in an amount of 40-50 wt.%, based on the total weight of the photopolymerizable composition.

9. The photopolymerizable composition of any of claims 3 to 7, wherein the first polymerization reaction product of components is present in an amount of 30 wt.% to less than 40 wt.%, based on the total weight of the photopolymerizable composition.

10. The photopolymerizable composition of claim 9, wherein the (meth)acrylate reactive diluent is present in an amount of 55-60 wt.%, based on the total weight of the photopolymerizable composition.

11. The photopolymerizable composition of claim 9 or claim 10, wherein the second polymerization reaction product of components is present in an amount of 5-12 wt.%, based on the total weight of the photopolymerizable composition.

12. The photopolymerizable composition of any of claims 9 to 11, wherein the crosslinker is present in an amount of 5-10 wt.%, based on the total weight of the photopolymerizable composition.

13. The photopolymerizable composition of claim 1 or claim 2, comprising:

30-50 wt.% of the (meth)acrylate reactive diluent; and

40-60 wt.% of the polymerization reaction product of components, the components comprising: a polymeric diol; and an azlactone.

14. The photopolymerizable composition of claim 13, wherein the azlactone comprises 2- vinyl-4,4-dimethylazlactone.

15. The photopolymerizable composition of claim 13 or claim 14, wherein the photopolymerizable composition further comprises a crosslinker.

16. The photopolymerizable composition of claim 15, wherein the crosslinker comprises a polymerized reaction product of a polyamine and an azlactone.

17. The photopolymerizable composition of any of claims 13 to 16, wherein the polymeric diol has a number average molecular weight (Mn) of 200 to 5,000 grams per mole (g/mol) or 400 to 3,000 g/mol, as determined by gel permeation chromatography.

18. The photopolymerizable composition of any of claims 13 to 17, wherein the polymeric diol comprises a polyester diol, a polycarbonate diol, a polyether diol, a polyolefin diol, or combinations thereof.

19. The photopolymerizable composition of any of claims 13 to 17, wherein the polymeric diol comprises a polycarbonate diol.

20. The photopolymerizable composition of any of claims 13 to 19, wherein the photopolymerizable composition further comprises an azlactone.

21. The photopolymerizable composition of any of claims 1 to 20, wherein the (meth)acrylate reactive diluent comprises at least one of isobornyl methacrylate, isobornyl acrylate, methyl methacrylate, tertiobutyl cyclohexyl methacrylate, 3,3,5- trimethylcyclohexyl methacrylate, or tricyclodecanedimethanol diacrylate.

22. The photopolymerizable composition of any of claims 1 to 21, wherein the photopolymerizable composition further comprises at least one of methacrylic acid, an antioxidant, or a UV absorber.

23. An orthodontic article comprising a polymerized reaction product of a photopolymerizable composition comprising:

45-60 wt.% of at least one (meth)acrylate reactive diluent, based on a total weight of the photopolymerizable composition; a photoinitiator; 30-50 wt.% of a first polymerization reaction product of components, based on the total weight of the photopolymerizable composition, the components comprising: a first polyether polyamine; and an ethylenically-unsaturated isocyanate functional monomer; optionally up to 10 wt.% of a crosslinker having a glass transition temperature (T_g) of 50°C or greater; and optionally up to 12 wt.% of a second polymerization reaction product of components, based on the total weight of the photopolymerizable composition, the components comprising: a second poly ether polyamine; and an ethylenically-unsaturated isocyanate functional monomer; with the provisos that:

A) when the first polymerization reaction product of components is present in an amount of 40-50 wt.%, the composition contains no more than 5 wt.% of the second polymerization reaction product of components; and

B) when the first polymerization reaction product of components is present in an amount of 30 wt.% to less than 40 wt.%, the composition includes at least one of the following: i) 55-60 wt.% of the (meth)acrylate reactive diluent; ii) 5-12 wt.% ofthe second polymerization reaction product of components; or iii) 5-10 wt.% ofthe crosslinker; or iv) 1-10 wt.% of methacrylic acid; wherein the polymerized reaction product has a T_g of 50°C or greater.

24. The orthodontic article of claim 23, wherein the polymerized reaction product of a photopolymerizable composition exhibits each of a tensile stress at break of 15 megapascals (MPa) or greater, a Young’s modulus of 300 MPa or greater, and a tensile strain at break of 65% or greater.

25. An orthodontic article or dental restoration tool comprising a polymerized reaction product of a photopolymerizable composition comprising:

30-50 wt.% of a (meth)acrylate reactive diluent; a photoinitiator; and

40-60 wt.% of a polymerization reaction product of components, the components comprising: a polymeric diol; and an azlactone, wherein the polymerized reaction product has a T_g of 50 °C or greater.