Photocurable composition

Abstract

To provide a photocurable composition containing a photocurable resin having both high toughness and high thermal stability.SOLUTION: A first prepolymer having a number-average molecular weight of 2000g / mol or less and being a reaction product of a first reaction mixture comprising a cycloaliphatic diisocyanate, a hydroxy-functional (meth) acrylate, and isocyanate-reactive components; and a second prepolymer having a number-average molecular weight of 2000g / mol to 10000g / mol and being a reaction product of a second reaction mixture comprising a cycloaliphatic diisocyanate, a hydroxy-functional (meth) acrylate, and isocyanate-reactive components; A second prepolymer comprising a (meth) acrylate and a polyactive hydrogen compound, wherein the polyactive hydrogen compound of the second reaction mixture has a Hansen-solubility parameter δ of less than 18. 9MPa1 / 2, and a reactive diluent comprising a (meth) acrylate monomer and / or a (meth) acrylate prepolymer; and a photoinitiator, wherein the photocurable composition has a shear viscosity of less than 50s·s at a shear rate of 1Pa - 1 at 100 °C.SELECTED DRAWING: None

Description

[Background technology]

[0001] Photocurable resins based on multifunctional (meth)acrylate monomers are commonly applied as thin films (e.g., protective coatings, printing inks) and are also used to fabricate bulk objects such as dental fillings and 3D-printed components. Urethane (meth)acrylate (UA) prepolymers are particularly attractive for 3D printing applications due to their exceptional flexibility, toughness, abrasion resistance, and weatherability. The addition of vinyl monomers reduces the resin's viscosity, improves processability, and / or modifies its physical properties (e.g., heat resistance, weather resistance). Many factors affect the mechanical properties of crosslinked UA resin formulations, including, for example, (a) the ratio of hard and soft segments in the UA prepolymer, (b) the molecular weight of the prepolymer, (c) the concentration and nature of the reactive diluent, and (d) the curing process.

[0002] In many demanding applications of photocurable resins, it is highly desirable to increase the toughness of the polymer while maintaining good thermal stability, which often requires increasing the glass transition temperature (Tg) of the cured polymer. Various approaches have been attempted to achieve these properties, but with limited success. For example, some photocurable resins can achieve high toughness (e.g., high tensile strength and high elongation at break) but lack thermal stability. Other photocurable resins can achieve high thermal stability but suffer from low toughness (e.g., low tensile elongation at break). Summary of the Invention

[0003] In one aspect, the present disclosure describes a photocurable composition that may include a photocurable resin and a photoinitiator. The photocurable composition is typically heated at 100° C. for 50 seconds. -1 The polymerizable composition may have a shear viscosity of less than 1 Pa·s at a shear rate of 1000 MPa and may typically comprise a first prepolymer, a second prepolymer, and a reactive diluent.

[0004] In another aspect, the present disclosure describes a crosslinked material that includes a photocurable composition after curing.

[0005] In yet another aspect, the present disclosure describes a method for producing a crosslinked material comprising exposing a photocurable composition to polymerizing electromagnetic radiation.

[0006] Thus, one or more features of the present invention have been outlined rather broadly in order that the detailed description that follows may be better understood, and in order that the present contributions to the art may be better appreciated. Other features of the present invention will become more apparent from the following detailed description of the invention when taken in conjunction with the appended claims, or may be learned by the practice of the invention. DETAILED DESCRIPTION OF THE INVENTION

[0007] Although the following detailed description contains many specifics for purposes of illustration, those skilled in the art will understand that many variations and modifications can be made to the following details and are considered to be included herein. Accordingly, the following embodiments are described without any loss of generality to, and without imposing limitations on, any claims set forth herein. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. Unless otherwise defined, 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.

[0008] As used herein, the singular forms "a," "an," and "the" are used where the context clearly indicates otherwise. Unless expressly stated, references to plural referents are inclusive. Thus, for example, a reference to "a polymer" or "the polymer" may include a plurality of such polymers.

[0009] In this application, the words "comprises," "comprising," and " "Containing," "having," and the like, may have the meanings given to them in U.S. patent law, and may mean "includes," "including," and the like, and are generally construed as open-ended terms. The terms "consisting of" or "consists of," as used pursuant to U.S. patent law, are limiting terms and include only those components, structures, steps, etc. that are specifically recited in connection with such term. "Essentially of" or "consists essentially of" have the meanings generally given them by U.S. patent law. In particular, such terms, while generally restrictive terms, may include additional items, materials, components, steps, or elements that do not materially affect the basic novel characteristics or function of the item or items with which they are used. For example, trace elements that are present in a composition but do not affect the properties or characteristics of the composition are not included in the terms "consisting essentially of." When present below, such terminology is acceptable even if not explicitly listed in the list of items that follows. When open-ended terms such as "comprising" or "including" are used herein, the term "comprising" or "including" does not include anything that is explicitly stated. The phrase "consisting essentially of" Not only that, but the phrase "consisting of" also provides direct support. It is understood that the same should be true for all other entities, and vice versa.

[0010] As used herein and in the claims, terms such as "first," "second," "third," "fourth," etc. are used to distinguish between like elements and not necessarily to describe a particular sequence or chronological order. It should be understood that any terms so used are interchangeable under appropriate circumstances, and that the embodiments described herein may, for example, operate in sequences other than those illustrated or otherwise described herein. Similarly, when a method is described herein as including a series of steps, the order of such steps presented herein is not necessarily the only order in which such steps may be performed; certain of the specified steps may be omitted and / or certain other steps not described herein may be added to the method.

[0011] As used herein, the term "substantially" refers to the complete or nearly complete extent or degree of an action, attribute, property, state, structure, item, or result. For example, "substantially" surrounding an object would mean that the object is completely surrounded or nearly completely surrounded. The precise acceptable degree of deviation from absolute completeness may depend on the specific context. Generally speaking, however, approximation to completeness would result in the same overall result as would be obtained with absolute and total completeness. The use of "substantially" is equally applicable when used in a negative sense, referring to the complete or nearly complete absence of an action, attribute, property, state, structure, item, or result. For example, a composition "substantially free" of particles would be either completely devoid of particles or nearly completely devoid of particles to the extent that the effect is similar to that of the complete absence of particles. In other words, a composition "substantially free" of a component or element may actually still contain such an item, so long as there is no measurable effect of such an item.

[0012] As used herein, the term "about" means that a given value exceeds the endpoints by "a little more than" The term "about" is used to provide flexibility in the endpoints of numerical ranges by providing the possibility that the value may be "around" or "slightly below." Unless otherwise specified, the use of the term "about" in conjunction with a particular numerical value or numerical range should also be understood to support such numerical term or range without the term "about." For example, for convenience and simplicity, a numerical range of "about 50 milligrams to about 80 milligrams" should also be understood to support the range "50 milligrams to 80 milligrams." Furthermore, in this specification, even when the term "about" is used in conjunction with other terms, it should be understood that the actual numerical value is supported. For example, a statement of "about" 30 should be interpreted as supporting not only values ​​slightly above 30 and values ​​slightly below 30, but also the actual numerical value of 30. Unless otherwise specified, all numerical parameters should be understood to be preceded and modified in all instances by the term "about," given the inherent variability of the underlying measuring technique used to determine the numerical value of the parameter.

[0013] As used herein, for convenience, a plurality of items, structural elements, components, and / or materials may be presented in common lists. However, these lists should be construed as though each member of the list were individually identified as a separate and unique element. Accordingly, no individual member of such a list should be construed as being effectively equivalent to any other member of the same list solely based on their presentation in a common group, absent indication to the contrary.

[0014] Concentrations, amounts, and other numerical data may be expressed or presented in range format herein. It should be understood that such range format is used merely for convenience and simplicity and should be interpreted flexibly as if each numerical value and subrange were explicitly recited, so as to include not only the numerical values ​​explicitly recited as the limits of the range, but also all individual numerical values ​​or subranges contained within that range. By way of example, a numerical range of "1 to 5" should be interpreted as including not only the explicitly recited values ​​1 to 5, but also each individual value and subrange within the stated range. Thus, this numerical range includes individual values ​​such as 2, 3, and 4, as well as subranges such as 1 to 3, 2 to 4, and 3 to 5, and individually 1, 2, 3, 4, and 5.

[0015] This same principle applies to ranges listing only one numerical value as a minimum or maximum value, and such interpretation should apply regardless of the broadness of the range or characteristic being described.

[0016] References throughout this specification to "one example" mean that the particular feature, structure, or characteristic described in connection with the example is included in at least one embodiment. Thus, the appearances of the phrase "in one example" in various places throughout this specification are not necessarily all referring to the same embodiment.

[0017] Embodiment Photocurable resin formulations can be used to fabricate complex objects, for example, by 3D printing. In the formulation, urethane (meth)acrylate (UA) prepolymers can contribute to the toughness (e.g., high tensile strength and elongation at break) of the photocured composition. Typically, UA prepolymers can be synthesized from multifunctional polyols, diisocyanates, and hydroxy-functional (meth)acrylates. Alternatively, UA prepolymers can be synthesized from multifunctional polyols and NCO-functional (meth)acrylates. Photocured UA prepolymers typically have glass transition temperatures (Tg) related to the structure of the polyurethane soft segment (e.g., below 50°C). Combining reactive diluents (e.g., high Tg (meth)acrylate monomers) with UA prepolymers allows for tunable curing. This approach provides desirable mechanical properties (e.g., modulus, elongation at break, etc.) and allows for the adjustment of working temperatures suitable for some demanding applications. One typical challenge with this approach is that when the reactive diluent content becomes the major component of the formulation (e.g., greater than 50 wt%), the toughness of the resin rapidly decreases due to a decrease in tensile elongation.

[0018] When UA prepolymers are synthesized using low-molecular-weight diols, the cured UA prepolymers often exhibit high Tg and high modulus, but poor tensile elongation at break. In some cases, this may be due to a high crosslink density of the polyurethane hard segments, such as when the molecular weight of the UA prepolymer is relatively low. In contrast, synthesizing UA prepolymers with higher molecular weights to improve mechanical properties can lead to high viscosities that can be difficult to manage in many applications. While this approach can strengthen compositions containing hard-segment prepolymers, it often limits improvements in resin toughness (e.g., tensile elongation at break).

[0019] In one aspect, the present disclosure relates to a photocurable composition having a high Tg and a manageable viscosity that can also provide good mechanical properties, and a method for making the same. The photocurable composition can include a blend of a first prepolymer having a high Tg after curing and a second prepolymer having a low Tg after curing, where the cured composition has a microphase-separated structure. In some examples, the first prepolymer can have a melting point below 60°C. In some examples, the second prepolymer can have a Tg below -40°C. In some additional examples, the photocurable composition can further include a reactive diluent suitable as a solvent for both prepolymers.

[0020] Without wishing to be bound by theory, it is believed that the first prepolymer and reactive diluent can form a high Tg crosslinked network as the dominant continuous phase, which co-crosslinks with the low Tg rubber network formed by the second prepolymer and reactive diluent. The low Tg rubber network can microphase separate from the high Tg crosslinked network and affect the toughness of the cured photocurable composition without significantly affecting the thermal stability of the dominant phase.

[0021] In contrast, if the high Tg network and the low Tg network are miscible in the cured state, the soft phase plasticizes the high Tg phase, resulting in good tensile strength and high transparency, but may also result in a strong yield point and low tensile elongation at break. Conversely, if the high Tg network and the low Tg network are immiscible and macrophase separation occurs in the cured state, the cured composition may not have a yield point, but the mechanical properties and transparency may be impaired. Therefore, due to the synergistic effect of the high Tg network and the low Tg network, the microphase-separated composition can achieve a high modulus, a yield point at strains greater than 5%, high tensile strength, and good transparency while maintaining good thermal stability.

[0022] For example, in some cases, photocurable compositions having microphase-separated structures in the cured state can be obtained by polymerization-induced phase separation. This can be achieved by balancing the molecular weights of the first and second prepolymers to promote homogeneous mixing before curing, but the soft phase separates from the hard phase after curing due to the incompatibility of these phases within the polymerized prepolymer.

[0023] In addition, the miscibility between two polymer networks is typically temperature dependent, typically being more miscible at higher temperatures. Therefore, considerations in designing a suitable photocurable composition may include prepolymer structure, molecular weight, and comparable miscibility at the intended photocuring temperature.

[0024] More specifically, in some examples, the photocurable composition can include a photocurable resin and a photoinitiator. The photocurable resin can typically include a first prepolymer, a second prepolymer, and a reactive diluent.

[0025] The first prepolymer can typically be present in the photocurable resin in an amount of 20% to 60% by weight, based on the total weight of the photocurable resin. In some additional examples, the first prepolymer can be present in the photocurable resin in an amount of 30% to 50% by weight, based on the total weight of the photocurable resin. In further additional examples, the first prepolymer can be present in the photocurable resin in an amount of 30% to 40%, 35% to 45%, or 40% to 50% by weight, based on the total weight of the photocurable resin.

[0026] The first prepolymer may typically have a number average molecular weight of 2000 g / mol or less as measured by gel permeation chromatography using a polystyrene retention time standard. Generally, gel permeation chromatography is used to determine all molecular weight values ​​disclosed herein, and in each example, a polystyrene retention time standard is used unless otherwise specified. In some additional examples, the first prepolymer may have a number average molecular weight of 1800 g / mol or less. In yet further examples, the first prepolymer may have a number average molecular weight of 1500 g / mol or less. In some further examples, the first prepolymer may have a number average molecular weight of 1200 g / mol or less, 1100 g / mol or less, 1000 g / mol or less, or 900 g / mol or less.

[0027] The first prepolymer can typically be the reaction product of a first reaction mixture including a cycloaliphatic diisocyanate, an isocyanate-reactive component, and a hydroxy-functional (meth)acrylate. The first reaction mixture can include various cycloaliphatic diisocyanates. Non-limiting examples of cycloaliphatic diisocyanates include cyclohexane-1,3-diisocyanate, cyclohexane-1,4-diisocyanate, 1-isocyanato-2-isocyanatomethylcyclopentane, 1-isocyanato-3-isocyanatomethyl-3,5,5-trimethylcyclohexane (isophorone diisocyanate or IPDI), bis-(4-isocyanatocyclohexyl)-methane (H 12 MDI), 1,3-bis(isocyanatomethyl)-cyclohexane, 1,4-bis(isocyanatomethyl)-cyclohexane, bis-(4-isocyanato-3-methyl-cyclohexyl)methane, 1-isocyanato-1-methyl-4(3)-isocyanatomethylcyclohexane, 2,4-hexahydrotoluylene diisocyanate, 2,6-hexahydrotoluylene diisocyanate, and the like, or combinations thereof. In some particular examples, the cycloaliphatic diisocyanate of the first reaction mixture may be IPDI, H 12In a further example, the cycloaliphatic diisocyanate of the first reaction mixture may include IPDI, MDI, or a combination thereof. In yet a further example, the cycloaliphatic diisocyanate of the first reaction mixture may include H 12 May include MDI.

[0028] In some examples, the first reaction mixture does not include any aromatic or aliphatic polyisocyanates other than the cycloaliphatic diisocyanate. In other examples, the first reaction mixture includes the cycloaliphatic diisocyanate in an amount of 80% to 100%, 90% to 100%, or 95% to 100% by weight, based on the total weight of all polyisocyanates present in the first reaction mixture.

[0029] The first reaction mixture can also include a variety of isocyanate-reactive components. As used herein, "isocyanate-reactive component" refers to a component that includes a hydroxyl group, an amino group, a thiol group, or a combination thereof. The isocyanate-reactive component can typically have a functionality of 2, or greater than 2. Thus, the isocyanate-reactive component can be or include a variety of components, including, but not limited to: The isocyanate-reactive component of the first reaction mixture may include polyols (e.g., diols, triols, etc.), polyamines (e.g., diamines, triamines, etc.), polythiols (e.g., dithiols, trithiols, etc.), or combinations thereof. In some examples, the isocyanate-reactive component of the first reaction mixture may include C2 to C6 12 In some further examples, the isocyanate-reactive component of the first reaction mixture can be or can include a linear or branched aliphatic polyol, polyamine, polythiol, or combination thereof; a C2 to C8 linear or branched aliphatic polyol, polyamine, polythiol, or combination thereof; a C4 to C8 10 Linear or branched aliphatic polyols, polyamines, polythiols, or combinations thereof; C6-C 12In some specific examples, the isocyanate-reactive component of the first reaction mixture may be or may include a linear or branched aliphatic polyol, a polyamine, a polythiol, or a combination thereof; or any mixture thereof. 12 In some further examples, the isocyanate-reactive component of the first reaction mixture can be or can include a linear or branched aliphatic polyol, a C2 to C8 linear or branched aliphatic polyol, a C4 to C8 10 Linear or branched aliphatic polyols, C6-C 12The isocyanate-reactive component may be or may include a linear or branched aliphatic polyol, or a combination thereof. Non-limiting examples of isocyanate-reactive components include ethylene glycol, 1,2-propanediol, 1,3-propanediol, glycerol, 1,3-butanediol, 2,3-butanediol, 1,4-butanediol, 2-methyl-1,4-butanediol, 3-methyl-1,3-butanediol, 1,2,4-butanetriol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 3-methyl-2,4-pentanediol, 2-methyl-1,3 -Pentanediol, 2-methyl-1,5-pentanediol, 1,2,5-pentanetriol, 1,6-hexanediol, 1,2-hexanediol, 1,5-hexanediol, 2-methyl-1,6-hexanediol, 4-methyl-1,3-hexanediol, 5-methyl-2,4-hexanediol, 3-methyl-1,6-hexanediol, 1,2,6-hexanetriol, 1,7-heptanediol, 2,5-heptanediol, 4-methyl-1,6-heptanediol Tandiol, 3-methyl-2,4-heptanediol, 2-methyl-2,6-heptanediol, 5-methyl-2,4-heptanediol, 4-methyl-1,7-heptanediol, 1,2,7-heptanetriol, 1,8-octanediol, 2-methyl-1,8-octanediol, 7-methyl-1,7-octanediol, 6-methyl-1,7-octanediol, 3-methyl-1,4-octanediol, 1,2,8-octanediol, 1,9-nonanediol , 8-methyl-1,8-nonanediol, 1,2,9-nonanetriol, 1,10-decanediol, 2-methyl-1,10-decanediol, 2-methyl-2,5-decanediol, 4,8-bis(hydroxymethyl)tricyclo[5.2.1.02,6]decane (DCPDM), 1,11-undecanediol, 1,12-dodecanediol, etc., or their corresponding polyamines, or their corresponding polythiols, or combinations thereof. In some specific examples, the isocyanate-reactive component can be or can include 3-methyl-1,5-pentanediol.In some additional specific examples, the isocyanate-reactive component can be or include 1,4-butanediol. In some further specific examples, the isocyanate-reactive component can be or include DCPDM. In yet further specific examples, the isocyanate-reactive component can be or include 1,9-nonanediol.

[0030] The cycloaliphatic diisocyanate and the isocyanate-reactive component can generally be combined in the first reaction mixture at an NCO / OH value of 1.2 to 3.0. For simplicity, NCO / OH value is used throughout this disclosure, but it is also noted that these descriptions are intended to equally describe NCO / NH or NCO / SH values, depending on the particular situation. In some additional examples, the cycloaliphatic diisocyanate and the isocyanate-reactive component can be combined in the first reaction mixture at an NCO / OH value of 1.3 to 2.3, 1.5 to 2.5, or 1. The cycloaliphatic diisocyanate and the isocyanate-reactive component can be combined in a ratio of 0.8 to 2.8. In some examples, the cycloaliphatic diisocyanate and the isocyanate-reactive component can be combined in the first reaction mixture before the hydroxy-functional (meth)acrylate is added to the first reaction mixture. In other examples, the cycloaliphatic diisocyanate, the isocyanate-reactive component, and the hydroxy-functional (meth)acrylate can be added simultaneously to the first reaction mixture.

[0031] The first reaction mixture can include various hydroxy-functional (meth)acrylates. The term "(meth)acrylate" as used herein refers to an acrylate and / or the corresponding methacrylate. In some examples, the hydroxy-functional (meth)acrylate is a C4 to C6 acrylate. 10 The hydroxy-functional (meth)acrylate may be or may include a hydroxyalkyl (meth)acrylate (i.e., a hydroxyalkyl (meth)acrylate containing a total of 4 to 10 carbon atoms). In some particular examples, the hydroxy-functional (meth)acrylate may be a C4 to C8 hydroxyalkyl (meth)acrylate and / or a C6 to C8 hydroxyalkyl (meth)acrylate. 10The hydroxy-functional (meth)acrylate may be or may include a hydroxyalkyl (meth)acrylate. Non-limiting examples of hydroxy-functional (meth)acrylates include hydroxymethyl acrylate, hydroxymethyl methacrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate, hydroxybutyl methacrylate, hydroxypentyl acrylate, hydroxypentyl methacrylate, hydroxyhexyl acrylate, hydroxyhexyl methacrylate, etc., or combinations thereof. In some specific examples, the hydroxy-functional (meth)acrylate of the first reaction mixture may be or may include hydroxyethyl acrylate and / or hydroxyethyl methacrylate. In some examples, the hydroxy-functional (meth)acrylate of the first reaction mixture may be or may include hydroxyethyl acrylate. In some examples, the hydroxy-functional (meth)acrylate of the first reaction mixture may be or may include hydroxyethyl methacrylate.

[0032] The second prepolymer can typically be present in the photocurable resin in an amount of 15% to 40% by weight, based on the total weight of the photocurable resin. In some additional examples, the second prepolymer can be present in the photocurable resin in an amount of 20% to 35% by weight, or 25% to 30% by weight, based on the total weight of the photocurable resin. In still further examples, the second prepolymer can be present in the photocurable resin in an amount of 15% to 25% by weight, 20% to 30% by weight, or 25% to 35% by weight, based on the total weight of the photocurable resin.

[0033] The second prepolymer of the photocurable resin can typically have a number average molecular weight of 2,000 g / mol to 10,000 g / mol as determined by gel permeation chromatography using polystyrene retention time standards. In some additional examples, the second prepolymer can have a number average molecular weight of 3,000 g / mol to 8,000 g / mol. In still further examples, the second prepolymer can have a number average molecular weight of 2,500 g / mol to 5,000 g / mol. In some further examples, the second prepolymer can have a number average molecular weight of 2,000 g / mol to 4,000 g / mol, 2,500 g / mol to 3,500 g / mol, or 3,000 g / mol to 6,000 g / mol.

[0034] The second prepolymer can be the reaction product of a second reaction mixture comprising a (meth)acrylate and a multi-active hydrogen compound. The photocurable resin can include a variety of second prepolymers. Non-limiting examples of the second prepolymer include a di(meth)acrylate-functionalized multi-active hydrogen compound (e.g., HEMA-PTMG-HEMA, for example); a second reaction mixture comprising an isocyanate-terminated (meth)acrylate and a multi-active hydrogen compound; The reaction product may be or may include a reaction product of a second reaction mixture comprising a diisocyanate, a hydroxy-functional (meth)acrylate, and a polyactive hydrogen compound; or a combination thereof.

[0035] The second reaction mixture can include various (meth)acrylates. In some examples, the (meth)acrylates of the second reaction mixture can be or include isocyanate-terminated (meth)acrylates. In some additional examples, the (meth)acrylates of the second reaction mixture can be hydroxy-functional (meth)acrylates. In some examples, the (meth)acrylates of the second reaction mixture can be C4 to C6 10 In some particular examples, the (meth)acrylate of the second reaction mixture can be or can include a C4 to C8 hydroxyalkyl (meth)acrylate and / or a C6 to C8 hydroxyalkyl (meth)acrylate.10 The hydroxy-functional (meth)acrylate may be or may include a hydroxyalkyl (meth)acrylate. Non-limiting examples of hydroxy-functional (meth)acrylates include hydroxymethyl acrylate, hydroxymethyl methacrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate, hydroxybutyl methacrylate, hydroxypentyl acrylate, hydroxypentyl methacrylate, hydroxyhexyl acrylate, hydroxyhexyl methacrylate, etc., or combinations thereof. In some specific examples, the hydroxy-functional (meth)acrylate of the second reaction mixture may be or may include hydroxyethyl acrylate and / or hydroxyethyl methacrylate. In some examples, the hydroxy-functional (meth)acrylate of the second reaction mixture may be or may include hydroxyethyl acrylate. In some examples, the hydroxy-functional (meth)acrylate of the second reaction mixture may be or may include hydroxyethyl methacrylate.

[0036] The second reaction mixture can also contain various polyactive hydrogen compounds. As used herein, "polyactive hydrogen compound" refers to any compound containing multiple Zerewitinoff-active hydrogen atoms. "Zerewitinoff-active hydrogen" refers herein to an acidic or active hydrogen atom that can be identified using known Zerewitinoff measurement methods (e.g., by reactivity with a corresponding Grignard reagent). In some specific examples, the polyactive hydrogen compound can be or can include a polyol (e.g., a diol, a triol, etc.), a polyamine (e.g., a diamine, a triamine, etc.), a polythiol (e.g., a dithiol, a trithiol, etc.), or a combination thereof.

[0037] In some examples, the multi-active hydrogen compound may have a number average molecular weight of 1000 g / mol to 5000 g / mol as determined by gel permeation chromatography using polystyrene retention time standards. In some additional examples, the multi-active hydrogen compound may have a number average molecular weight of 1200 g / mol to 4000 g / mol or 1400 g / mol to 3000 g / mol. In some specific examples, the multi-active hydrogen compound may have a number average molecular weight of 1000 g / mol to 1500 g / mol, 1200 g / mol to 2000 g / mol, 1500 g / mol to 2500 g / mol, 2000 g / mol to 3000 g / mol, or 2500 g / mol to 3500 g / mol.

[0038] In some examples, the polyactive hydrogen compound has a viscosity of 18.9 MPa 1 / 2 In some additional examples, the polyactive hydrogen compound may have a Hansen solubility parameter δ of less than 16 MPa. 1 / 2 Larger than 18.9 MPa 1 / 2 The total solubility parameter (δ) may be a smaller Hansen solubility parameter, δ. Hansen describes the total solubility parameter (δ) as a combination of three components reflecting dispersive (δD), polar (δP), and hydrogen bonding (δH) interactions: δ 2 =δ 2 TOT= δD 2 +δP 2 +δH 2 The components δD, δP, and δH are calculated using the Hansen solubility parameters. Hansen also defines a 3D solubility diagram (δD, δP, δH) that can define the solubility sphere range with radius R0 for large molecules. Analysis of polymer HSP is based on solubility testing in solvents with known HSP, as described in Appendix A of Hansen Solubility Parameters, A User Guidebook, 2007, CRC Press. Based on the solubility test described, the total δ for Desmophen 1200 is 21.6 MPa. 1 / 2and the total δ of PTMG is 17.6 MPa. 1 / 2 and the total δ of the PPG is 18.9 MPa. 1 / 2 It was required that this be the case.

[0039] In some additional examples, the second reaction mixture can include a diisocyanate. When the second reaction mixture includes a diisocyanate, the diisocyanate can generally include a cycloaliphatic diisocyanate, an aromatic diisocyanate, or a combination thereof. In some examples, the diisocyanate of the second reaction mixture can be or can include a cycloaliphatic diisocyanate. In this case, the cycloaliphatic diisocyanate can be cyclohexane-1,3-diisocyanate, cyclohexane-1,4-diisocyanate, 1-isocyanato-2-isocyanatomethylcyclopentane, IPDI, H 12 In some specific examples, the cycloaliphatic diisocyanate of the second reaction mixture can be or include MDI, 1,3-bis(isocyanatomethyl)-cyclohexane, 1,4-bis(isocyanatomethyl)-cyclohexane, bis-(4-isocyanato-3-methyl-cyclohexyl)methane, 1-isocyanato-1-methyl-4(3)-isocyanatomethylcyclohexane, 2,4-hexahydrotoluylene diisocyanate, 2,6-hexahydrotoluylene diisocyanate, and the like, or combinations thereof. 12 In a further example, the cycloaliphatic diisocyanate of the second reaction mixture may include IPDI, MDI, or a combination thereof. In yet a further example, the cycloaliphatic diisocyanate of the second reaction mixture may include H 12It may include MDI. In other examples, the diisocyanate of the second reaction mixture may be or may include an aromatic diisocyanate. In this case, the aromatic diisocyanate of the second reaction mixture may be or may include methylene diphenyl diisocyanate (MDI) (e.g., 2,4'-MDI, 4,4'-MDI, or a mixture thereof), toluene diisocyanate (TDI) (e.g., 2,4-TDI, 2,6-TDI, or a mixture thereof), or a combination thereof. In some examples, the aromatic diisocyanate of the second reaction mixture may be or may include MDI.

[0040] When the second reaction mixture includes a diisocyanate, the diisocyanate and the multi-active hydrogen compound can generally be combined in the second reaction mixture at an NCO / OH value of 1.2 to 3.0. In some additional examples, the diisocyanate and the multi-active hydrogen compound can be combined in the second reaction mixture at an NCO / OH value of 1.3 to 2.3, 1.5 to 2.5, or 1.8 to 2.8. In some specific examples, the diisocyanate and the multi-active hydrogen compound can be combined in the second reaction mixture at an NCO / OH value of 2.

[0041] The photocurable resin may also include a reactive diluent. The reactive diluent may typically be present in the photocurable resin in an amount of 20% to 65% by weight, based on the total weight of the photocurable resin. In some additional examples, the reactive diluent may be present in the photocurable resin in an amount of 30% to 50% by weight, or 40% to 60% by weight, based on the total weight of the photocurable resin. In further additional examples, the reactive diluent may be present in the photocurable resin in an amount of 25% to 35% by weight, 35% to 45% by weight, or 40% to 50% by weight, based on the total weight of the photocurable resin.

[0042] Various reactive diluents can be included in the photocurable resin. In some examples, the reactive diluent is C 10 ~C 18 It may be a (meth)acrylate monomer or C 10 ~C 18 Non-limiting examples of (meth)acrylate monomers include isobornyl acrylate, isobornyl methacrylate, cyclohexyl methacrylate, cis-4-tert-butyl-cyclohexyl methacrylate, 4-tert-butylcyclohexyl methacrylate, 3,3,5-trimethylcyclohexyl acrylate, 3,3,5-trimethylcyclohexyl methacrylate, dicyclopentanyl acrylate, dicyclopentanyl methacrylate, 3,5-dimethyl-1-adamantyl acrylate, 3, Examples of the alkyl acrylate include 5-dimethyl-1-adamantyl methacrylate, tert-butyl methacrylate, 2-decahydronaphthyl methacrylate, 1-adamantyl acrylate, 1-adamantyl methacrylate, 2-ethylhexyl methacrylate, 3-tricyclo[4.4.0.1.1]dodecyl methacrylate, tetrahydrofurfuryl methacrylate, 2-phenoxyethyl methacrylate, N-vinylpyrrolidone, carboxyethyl acrylate, acryloylmorpholine, and the like, or combinations thereof.

[0043] In addition to the photocurable resin, the photocurable composition may also include a photoinitiator. The photocurable composition can include a variety of photoinitiators. Non-limiting examples include BASF's IRGACURE and DAROCUR, such as 1-hydroxycyclohexyl phenyl ketone (IRGACURE 184), 2,2-dimethoxy-1,2-diphenylethan-1-one (IRGACURE 651), bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (IRGACURE 819), 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propan-1-one (IRGACURE 2959), 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone (IRGACURE 369), 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one (IRGACURE 369), and the like. 907), oligo[2-hydroxy-2-methyl-1[4-(1-methylvinyl)phenyl]propane] (ESACURE ONE), 2-hydroxy-2-methyl-1-phenylpropan-1-one (DAROCUR 1173), 2,4,6-trimethylbenzoyldiphenylphosphine oxide (IRGACURE TPO), and 2,4,6-trimethylbenzoylphenylphosphinate (IRGACURE TPO-L), or the like, or combinations thereof. Additional non-limiting examples of photoinitiators include benzil dimethyl ketal, 2-methyl-2-hydroxypropiophenone, benzoin methyl ether, benzoin isopropyl ether, anisoin methyl ether, aromatic sulfonyl chlorides, photoactivatable oximes, etc., or combinations thereof.

[0044] The photocurable composition may optionally include various additives. Non-limiting examples of additives include impact modifiers, colorants, thickeners, resins, antifoaming agents, surfactants, UV absorbers, flame retardants, etc., or combinations thereof. In some specific examples, the photocurable composition may include a colorant. The type of colorant is not particularly limited, and any suitable colorant (e.g., dyes, pigments, etc., or combinations thereof) may be used in the photocurable composition. In some additional specific examples, the photocurable composition may include an impact modifier. The type of impact modifier is not particularly limited, and any suitable impact modifier (e.g., liquid rubber, core-shell rubber particles, etc., or combinations thereof) may be used in the photocurable composition.

[0045] The photocurable composition may have various viscosities depending on the application. Typically, the photocurable composition is heated at 100°C for 50 seconds. -1 In some additional examples, the photocurable composition may have a shear viscosity of less than 1 Pa·s at a shear rate of 80° C., 50 s -1 In yet an additional example, the photocurable composition may have a shear viscosity of less than 1 Pa·s at a shear rate of 70°C, 50 s -1 The polymer may have a shear viscosity of less than 1 Pa·s at a shear rate of

[0046] The present disclosure also describes a method for making a photocurable composition. Generally, the method comprises: The photocurable resin may be prepared by combining a first prepolymer, a second prepolymer, and a reactive diluent.

[0047] The first prepolymer can be prepared in a variety of ways. In some examples, the first prepolymer can be prepared by combining a cycloaliphatic diisocyanate and an isocyanate-reactive component to form a first product. Typically, the isocyanate-reactive component can be added gradually to the cycloaliphatic diisocyanate to minimize exotherm and narrow the molecular weight distribution. The first product can be combined with a hydroxy-functional (meth)acrylate to form the first prepolymer. In another example, the first prepolymer can be prepared by combining a cycloaliphatic diisocyanate with a hydroxy-functional (meth)acrylate to form an isocyanate-terminated (meth)acrylate. The isocyanate-terminated (meth)acrylate can then be combined with the isocyanate-reactive component to form the first prepolymer.

[0048] The second prepolymer can also be prepared in a variety of ways. In some examples, the second prepolymer can be prepared by combining a (meth)acrylate and a polyactive hydrogen compound under conditions suitable to form a di(meth)acrylate-functionalized polyactive hydrogen compound (e.g., HEMA-PTMG-HEMA, etc.). In other examples, the second prepolymer can be prepared by combining a diisocyanate with a (meth)acrylate to form an isocyanate-terminated (meth)acrylate. The isocyanate-terminated (meth)acrylate can be combined with a polyactive hydrogen compound to form the second prepolymer. In yet another example, the second prepolymer can be formed by combining a diisocyanate with a polyactive hydrogen compound to form a second product. Typically, the polyactive hydrogen compound can be added gradually to the diisocyanate to minimize exotherm. The second product can be combined with a (meth)acrylate to form the second prepolymer.

[0049] The first prepolymer and the second prepolymer can typically be homogeneously mixed with a reactive diluent to form a photocurable resin. Adding a photoinitiator to the photocurable resin can form a photocurable composition. Prior to photocuring, the photocurable composition can optionally be heated to a temperature suitable for photocuring. In other instances where photocuring is intended to occur at or below ambient temperature, heating may not be necessary. In some instances, the prepolymers may become more miscible as the temperature increases.

[0050] The present disclosure also describes crosslinked materials prepared by curing the photocurable compositions and methods of making the same. More specifically, the photocurable compositions can be exposed to suitable electromagnetic radiation to at least partially crosslink the photocurable compositions to form at least a portion of the crosslinked material.

[0051] In some examples, the crosslinked material may have a transparent or translucent appearance. In some specific examples, the crosslinked material may have a transparency or percent transmittance of 75% or greater at room temperature based on ASTM D1003 using a film having a thickness of 0.3 mm. In other examples, the crosslinked material may have a transparency or percent transmittance of 80% or greater at room temperature. In yet additional examples, the crosslinked material may have a transparency or percent transmittance of 85% or greater at room temperature.

[0052] The present disclosure also describes methods for producing crosslinked materials. In some examples, the methods can include applying (e.g., casting, coating, painting, rolling, dipping, spraying, depositing, etc.) a photocurable composition described herein to at least a portion of a substrate. Any suitable substrate can be used, such as wood, plastic, ceramic, metal, glass, etc. The photocurable composition can be cured (e.g., by exposure to electromagnetic radiation sufficient to induce photopolymerization) to form a crosslinked material on the substrate, or in other words, a coated substrate comprising a coating of crosslinked material.

[0053] In some additional examples, the method for producing the cross-linked material may be or include an additive manufacturing method. Additive manufacturing refers to a method for producing a product based on a 3D object model (e.g., a CAD model, etc.) by adding materials together, typically layer by layer, for example, by material deposition, material bonding, material solidification, or a combination thereof. In some specific examples, the additive manufacturing method may be or include stereolithography, digital light processing, continuous liquid interface manufacturing, etc. Other suitable additive manufacturing methods may also be used. In addition, other suitable non-additive manufacturing methods may be used to prepare the cross-linked material.

[0054] Photocurable compositions are typically cured at 100°C for 50 seconds. -1 The photocurable composition may have a shear viscosity of less than 1 Pa·s at a shear rate of 100°C. Thus, for coatings and additive manufacturing methods using photopolymerization, the photocurable compositions described herein can be applied as films / coatings or printed as 2D or 3D objects at relatively low temperatures. For example, in some cases, the photocurable composition can be applied or printed at a temperature of less than 100°C. In further additional examples, the photocurable composition can be applied or printed at a temperature of less than 90°C, less than 80°C, less than 70°C, less than 60°C, or less than 50°C. In some specific examples, the photocurable composition can be applied or printed at a temperature of 20°C to 100°C. In some additional examples, the photocurable composition can be applied or printed at a temperature of 20°C to 60°C or 20°C to 40°C.

[0055] Additionally, in some cases, curing (e.g., exposure to electromagnetic radiation sufficient to induce photopolymerization) can also occur at relatively low temperatures. In some specific examples (e.g., in DLP printing, etc.), curing and printing can occur in the same step. In other examples, applying / printing and curing can occur sequentially (e.g., applying a coating to a substrate and then curing the coating to form a coated substrate). In some examples, curing can occur at a temperature below 100°C. In still additional examples, curing can occur at a temperature below 90°C, below 80°C, below 70°C, below 60°C, or below 50°C. In some specific examples, curing can occur at a temperature between 20°C and 100°C. In some additional examples, curing can occur at a temperature between 20°C and 60°C or between 20°C and 40°C.

[0056] In some examples, a manufacturing method can include introducing a photocurable composition into a container. The container can be positioned so that the photocurable composition sufficiently contacts or covers a substrate or build platform. The portion of the substrate or build platform that contacts or is covered by the photocurable composition can depend on the direction(s) from which the photocurable composition is exposed to polymerizing electromagnetic radiation.

[0057] As used herein, "polymerizing electromagnetic radiation" can include any type of electromagnetic radiation suitable for promoting or inducing photopolymerization of a photocurable composition. In some examples, polymerization electromagnetic radiation can be or include ultraviolet electromagnetic radiation (e.g., electromagnetic radiation inducing wavelengths from 10 nm to 400 nm). In some examples, polymerization electromagnetic radiation can be or include visible electromagnetic radiation (e.g., electromagnetic radiation having a wavelength from 380 nm to 750 nm). In some examples, polymerization electromagnetic radiation can be or include infrared electromagnetic radiation (e.g., electromagnetic radiation having a wavelength from 700 nm to 1 mm).

[0058] The photocurable composition can be exposed to the polymerizing electromagnetic radiation for a time suitable to photopolymerize the photocurable composition and form a crosslinked material. The length of time can depend on the wavelength of the electromagnetic radiation, the intensity of the electromagnetic radiation, the thickness of the photocurable composition, etc. In some examples, the photocurable composition can be exposed to the polymerizing electromagnetic radiation multiple times, such as multiple times for a single layer, or one or more times for each of multiple layers or segments, or a combination thereof, to form a crosslinked material.

[0059] When applying a photocurable composition via additive manufacturing, the photocurable composition can be printed based on a 3D object model to form a 3D crosslinked material. For example, based on the 3D object model for the crosslinked material, the photocurable composition can be applied to a build platform and selectively exposed to electromagnetic radiation for polymerization to form a crosslinked interface layer that connects to the build platform. Based on the 3D object model, additional photocurable compositions can be applied to the interface layer (and / or additional crosslinked layers) and selectively exposed to electromagnetic radiation for polymerization to form one or more additional crosslinked layers until the 3D object is complete based on the 3D object model. In some examples, applying additional photocurable compositions to the interface layer and / or additional crosslinked layer(s) can include moving the build platform a distance of at least 1 μm and at most 2000 μm to apply additional photocurable compositions to the crosslinked interface layer and / or additional crosslinked layer(s). In some examples, applying the additional photocurable composition to the interface layer and / or the additional crosslinked layer(s) can include depositing the photocurable composition to the interface layer and / or the additional crosslinked layer(s) with or without moving the build platform.

[0060] The photocurable composition can be cured to form a crosslinked material comprising a co-crosslinked polymer network including a first polymer network having a first Tg and a second polymer network having a second Tg. The first polymer network can include a crosslinked first prepolymer and a reactive diluent. The first Tg can typically be greater than 80°C based on dynamic mechanical analysis with a 3°C / min heating ramp and a 1 Hz frequency for the loss modulus (E'') peak. In yet additional examples, the first Tg can be greater than 100°C or greater than 120°C based on dynamic mechanical analysis with a 3°C / min heating ramp and a 1 Hz frequency for the loss modulus (E'') peak.

[0061] The second polymer network can include a crosslinked second prepolymer and a reactive diluent. The second Tg can typically be less than −40° C. based on dynamic mechanical analysis at a 3° C. / min heating ramp and 1 Hz frequency for the loss modulus (E″) peak. In yet additional examples, the second Tg can be less than −50° C. or less than −60° C. based on dynamic mechanical analysis at a 3° C. / min heating ramp and 1 Hz frequency for the loss modulus (E″) peak.

[0062] The cross-linked material may have a variety of mechanical properties. In some examples, the cross-linked material may have a yield strain of 5% or greater based on tensile testing ASTM D638, Type 4 specimens using a tensile speed of 50 mm / min under ambient conditions. In further examples, the cross-linked material may have a yield strain of 6% or greater or 8% or greater based on tensile testing ASTM D638, Type 4 specimens using a tensile speed of 50 mm / min under ambient conditions.

[0063] In some additional examples, the cross-linked material may have an elastic modulus of 900 MPa or greater based on ASTM D638, Type 4 specimens using a tensile speed of 50 mm / min under ambient conditions. In still further examples, the cross-linked material may have an elastic modulus of 1000 MPa or greater based on ASTM D638, Type 4 specimens using a tensile speed of 50 mm / min under ambient conditions. The elastic modulus may be 1200 MPa or more, or 1500 MPa or more.

[0064] In some further examples, the cross-linked material may have a tensile stress at break of 30 MPa or greater based on an ASTM D638, Type 4 specimen using a tensile speed of 50 mm / min under ambient conditions. In still further examples, the cross-linked material may have a tensile stress at break of 35 MPa or greater or 40 MPa or greater based on an ASTM D638, Type 4 specimen using a tensile speed of 50 mm / min under ambient conditions.

[0065] In some additional examples, the crosslinked material may have an elongation at break of 15% or greater based on an ASTM D638, Type 4 specimen using a tensile speed of 50 mm / min under ambient conditions. In yet additional examples, the crosslinked material may have an elongation at break of 20% or greater, 25% or greater, or 30% or greater based on an ASTM D638, Type 4 specimen using a tensile speed of 50 mm / min under ambient conditions.

[0066] In some particular examples, the cross-linked material can be a 3D printed object. The 3D printed object can be formed by various 3D printing methods. In some particular examples, the 3D printing method can be or can include digital light processing (DLP).

[0067] In some further examples, the 3D printed object can form at least a portion of a medical device. Non-limiting examples of medical devices can include orthodontic appliances (e.g., dental aligners, dental retainers, surgical guides, etc.), hearing appliances (e.g., hearing aids, cochlear implants, etc.), and orthopedic appliances (e.g., braces, casts, skull plates, prosthetic devices, etc.). In some specific examples, the 3D printed object can be or include a dental aligner, surgical guide, hearing aid, or cochlear implant. [Example]

[0068] Materials used in the examples: Diol A 3-methyl-1,5-pentanediol (1,5-MPD) Diol B 1,4-butanediol (1,4-BDO) Diol C 4,8-bis(hydroxymethyl)tricyclo[5.2.1.02,6]decane (DCPDM) Diol D 1,9-nonanediol Diol E DESMOPHEN C2202 commercially available from COVESTRO Diol F DESMOPHEN PE225B commercially available from COVESTRO Diol G DESMOPHEN C1200 commercially available from COVESTRO Diol H ARCOL PPG 2000 commercially available from COVESTRO Diol I VELVETOL H2000 commercially available from ALLESSA Diol J Poly(tetrahydrofuran) (PTMG) 1000 Diol K PTMG 2000 Diol L PTMG 2900 Acrylate A Hydroxyethyl Methacrylate (HEMA) Acrylate B Hydroxyethyl acrylate (HEA) Acrylate C: PLACCEL FM1 commercially available from DAICEL Acrylate D Isobornyl methacrylate (IBOMA) Acrylate E Isobornyl acrylate (IBOA) Acrylate F Cyclohexyl methacrylate (CHMA) Acrylate G 4-tert-butylcyclohexyl methacrylate (t-BuCHMA) Isocyanate A: Isophorone diisocyanate (IPDI) Isocyanate B 4,4'-Diisocyanatodicyclohexylmethane (H 12 MDI)

[0069] Example 1 - Synthesis of UA prepolymer Solid diol samples were heated overnight in a 60°C oven before use. 10 wt% catalyst (e.g., dibutyltin dilaurate) solution in ethyl acetate, 10 wt% phenothiozine solution in ethyl acetate, and 5 wt% butylated hydroxytoluene in ethyl acetate were used. A diisocyanate (BHT) solution was prepared for use in prepolymer synthesis. At room temperature, the diol was mixed in ethyl acetate in a three-neck reactor equipped with a reflux condenser, thermocouple, and mechanical stirrer until a homogeneous solution was achieved. A catalyst (100 ppm) solution was added to the mixture. The stirring speed was set at 500 rpm, and the reaction was blanketed with nitrogen. After raising the temperature to 60°C, the diisocyanate was added dropwise to the reactor within approximately 15 minutes. A dry ice bath was used to cool the reactor and maintain the solution temperature below 70°C. After 1 hour, the NCO content was titrated against the NCO target. If the target was not achieved, the reaction was continued for an additional 30 minutes until the target was reached. Then, phenothiozine (50 ppm) and additional catalyst (400 ppm) were added to the reactor. The hydroxy-functional (meth)acrylate was added to the solution within 15 minutes. After 60 minutes, the NCO content was titrated, and the reaction was stopped when the NCO content reached less than 0.2 wt%. The reaction mixture was cooled to room temperature. Finally, the NCO content was titrated, and BHT (100 ppm) was added to the solution. In the synthesis, solvents can be replaced with reactive diluents.

[0070] TIFF2026021455000001.tif109170

[0071] TIFF2026021455000002.tif64170

[0072] Example 2 - Film preparation and evaluation All prepolymers were synthesized at 75 wt% in ethyl acetate. The prepolymers were then mixed with reactive diluents in the amounts shown in Tables 3, 5, 7, and 9, and further mixed with photoinitiator (3 wt% based on prepolymer solids) using a speed mixer to prepare photocurable compositions. The photocurable compositions were then heated at 100°C for 50 s. -1 The photocurable composition was cast into a 400 micron wet film and cured using a Liberty conveyor UV oven. The UV curing conditions were 200 W at 105 amps, 14 fpm (1530 mJ / cm). 2 ) A double pass post-heat cure followed by drying under ambient conditions: 80°C, 100°C and 125°C for 30 minutes each removed residual volatiles.

[0073] The film samples were then cut into Type 4 dog-bone specimens using a die cutter. Tensile tests were performed according to ASTM D638 at 23°C and 50% RH using an Instron 5900R equipped with a 10 kN load cell. The tensile speed was 50 mm / min. .

[0074] The hard segment prepolymer and reactive diluent were held constant, as can be seen in Table 3. Varying types and / or amounts of soft segment prepolymer were combined with the hard segment prepolymer and reactive diluent to determine the effect on the mechanical properties of the crosslinked material. The results of the mechanical testing can be seen in Table 4.

[0075] The soft segment prepolymers of Films 1 to 5 of the present invention are based on low Tg polyols with Mn greater than 2000. These polyols are relatively hydrophobic (Hansen solubility parameter of 18.9 MPa 1 / 2 When using the same hard segment prepolymer, the low Tg soft segment prepolymer exhibits desirable tensile properties (modulus greater than 900 MPa, tensile stress at break greater than 30 MPa, elongation at break greater than 15%, and yield strain greater than 5%).

[0076] Comparative films 1 to 5 have low hydrophobicity (Hansen solubility parameter of 18.9 MPa) 1 / 2 (greater than 0.05 g / mol), or Mn less than 2000 g / mol, or Tg greater than -40°C. In addition, the cured films exhibit relatively low tensile elongation at break and yield points less than 5%, despite exhibiting high modulus and tensile stress. Generally, Comparative Films 1-5 are also more brittle. For Comparative Film 6, a mixture of two polyols was used to synthesize the prepolymer, and the resulting film exhibits a yield point less than 5%, despite good mechanical properties.

[0077] TIFF2026021455000003.tif88170

[0078] TIFF2026021455000004.tif95170

[0079] As seen in Table 5, inventive films 6-9 each contain a different type of hard segment prepolymer in combination with the same type of soft segment prepolymer. As seen in Table 6, inventive films 6-9 exhibit similar tensile properties (modulus greater than 1000 MPa, tensile stress greater than 30 MPa, tensile elongation at break greater than 15%, and yield strain greater than 5%).

[0080] Comparative Films 7 and 8 used a high Tg dimethacrylate crosslinker that does not contain urethane groups. Comparative Films 7 and 8 do not exhibit the desired tensile properties. These examples clearly demonstrate the benefits of using hard segment UA prepolymers.

[0081] TIFF2026021455000005.tif83170

[0082] TIFF2026021455000006.tif52170

[0083] Various reactive diluents were combined with various hard and soft segment prepolymers to determine the effect of the reactive diluents on mechanical properties, as seen in Table 7. The results of the mechanical testing can be seen in Table 8. As can be seen from these results, inventive films 10-12 exhibited similar desirable tensile properties when different high Tg reactive diluents were used in the formulation.

[0084] TIFF2026021455000007.tif47170

[0085] TIFF2026021455000008.tif33170

[0086] Table 9 shows the formulation of photocurable resins with various molecular weights to determine the effect of molecular weight on the mechanical properties of the crosslinked materials. The results of the mechanical testing are shown in Table 10. As can be seen, inventive films 13-17 and 6 exhibited desirable tensile properties, even though they utilized various hard and soft segment prepolymer structures.

[0087] TIFF2026021455000009.tif74170

[0088] TIFF2026021455000010.tif55170

[0089] Dynamic mechanical analysis (DMA) was performed on inventive films 6 and 13 and comparative films 3, 4, and 6 using a 3°C / min heat ramp and 1 Hz frequency to determine the Tg of the cured hard segment prepolymer network and the cured soft segment prepolymer network after curing each photocurable composition. Each inventive film exhibits two distinct Tg points, below -40°C and above 100°C, respectively, based on the loss modulus (E'') peak in the DMA analysis. Comparative films 3 and 4 generally exhibited higher soft segment Tg and lower hard segment Tg. Comparative film 6 exhibited distinct soft segment Tg and lower hard segment Tg, likely due to more phase mixing in the cured resin when the two polyols were combined in the synthesis. It does not exhibit a segment Tg.

[0090] TIFF2026021455000011.tif41170

[0091] It should be understood that the above examples are merely illustrative of some embodiments of the present invention. Numerous modifications and alternative arrangements may be devised by those skilled in the art without departing from the spirit and scope of the present invention, and the appended claims are intended to cover such modifications and arrangements. Thus, while the present invention has been described with specificity and detail in connection with what are presently considered to be the most practical and preferred embodiments thereof, it will be apparent to those skilled in the art that changes can be made without departing from the principles and concepts set forth herein.

Claims

1. A photocurable composition comprising: A photocurable resin, a first prepolymer having a number average molecular weight of 2000 g / mol or less, an alicyclic diisocyanate; a hydroxy-functional (meth)acrylate; and an isocyanate-reactive component; and a first prepolymer that is the reaction product of a first reaction mixture comprising: a second prepolymer having a number average molecular weight of 2000 g / mol to 10000 g / mol; (meth)acrylate, a polyactive hydrogen compound; wherein the polyactive hydrogen compound of the second reaction mixture is a reaction product of １／２ a second prepolymer having a Hansen solubility parameter δ of less than a reactive diluent comprising a (meth)acrylate monomer and / or a (meth)acrylate prepolymer; a photocurable resin comprising: a photoinitiator; and Including, 100°C, 50s －１ The photocurable composition has a shear viscosity of less than 1 Pa·s at a shear rate of 1000 rpm.

2. The photocurable composition of claim 1 , wherein the cycloaliphatic diisocyanate of the first reaction mixture comprises isophorone diisocyanate.

3. the hydroxy-functional (meth)acrylate of the first reaction mixture is ４ ~C １０ The photocurable composition of claim 1 comprising a hydroxyalkyl (meth)acrylate.

4. the isocyanate-reactive component of the first reaction mixture is C ２ ~C １２ The photocurable composition of claim 1 comprising an aliphatic diol.

5. The (meth)acrylate of the second reaction mixture is C ４ ~C １０ The photocurable composition of claim 1 comprising a hydroxyalkyl (meth)acrylate.

6. The photocurable composition of claim 1 , wherein the second reaction mixture further comprises a diisocyanate.

7. The photocurable composition of claim 6 , wherein the diisocyanate comprises a cycloaliphatic diisocyanate.

8. The polyactive hydrogen compound of the second reaction mixture is heated to 16 MPa １／２ Larger than 18.9 MPa １／２ 10. The photocurable composition of claim 1, having a smaller Hansen solubility parameter δ.

9. The reactive diluent is C １０ ~C １８ The photocurable composition of claim 1 comprising a (meth)acrylate monomer.

10. The photocurable resin is 30% by weight to 50% by weight based on the total weight of the photocurable resin. The photocurable composition of claim 1 comprising a first prepolymer.

11. 10. The photocurable composition of claim 1, wherein the photocurable resin comprises 25% to 30% by weight of the second prepolymer, based on the total weight of the photocurable resin.

12. 2. The photocurable composition of claim 1, wherein the photocurable resin comprises 30% to 40% by weight of the reactive diluent, based on the total weight of the photocurable resin.

13. 10. A crosslinked material comprising the photocurable composition of claim 1, which upon curing forms a co-crosslinked polymer network comprising a first polymer network having a first Tg and a second polymer network having a second Tg.

14. 14. The crosslinked material of claim 13, wherein the first Tg is greater than 80°C.

15. 14. The crosslinked material of claim 13, wherein the second Tg is less than -40°C.

16. 14. The crosslinked material of claim 13, having a % transmittance of 75% or greater at room temperature based on ASTM D1003 using a 0.3 mm thick film.

17. 14. The cross-linked material of claim 13, which is a 3D printed article.

18. 20. The cross-linked material of claim 17, wherein the 3D printed article forms at least a portion of a medical device.

19. 20. The cross-linked material of claim 18, wherein the medical device is an orthodontic appliance, a hearing appliance, or an orthopedic appliance.

20. 10. A method of producing a crosslinked material comprising the step of exposing the photocurable composition of claim 1 to polymerizing electromagnetic radiation to form a crosslinked material.

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