TWI820340B - Resin materials for making three-dimensional objects and methods of using the same - Google Patents

Abstract

A polymerizable liquid that can be used for producing three-dimensional objects by methods of additive manufacturing is disclosed. The polymerizable liquid may comprise: (a) a blocked or reactively blocked polyurethane prepolymer; (b) (optional) a reactive diluent; (c) a blocked or reactively blocked curing agent; (d) a photoinitiator; and (e) (optional) a blocked or reactively blocked diisocyanate. The method using such polymerizable liquid to form three-dimensional objects is also described.

Description

Resin materials for preparing three-dimensional objects and methods of using them

The present application relates to polymerizable resin materials and methods of producing three-dimensional objects using the materials.

This application claims priority to U.S. Provisional Application No. 62/942,678, filed on December 2, 2019, and U.S. Provisional Application No. 62/982,154, filed on February 27, 2020, and Priority to the PCT application with application number PCT/CN2020/095715 filed on June 12, 2020, the entire content of which is incorporated into this application by reference.

Light-curing 3D printing technology uses light-curable resin as raw material, which is cured under the irradiation of visible light or ultraviolet light. Photocurable resins are generally in a liquid state and undergo photopolymerization under the irradiation of visible light or ultraviolet light of a specific wavelength to complete curing. In a typical stereolithography 3D printing process, three-dimensional objects are formed layer by layer. Each layer is formed by projecting the two-dimensional pattern of the layer onto a photocurable liquid resin, thereby curing the liquid resin to obtain a solid shape that matches the two-dimensional pattern. The pattern is usually displayed on a programmable display, such as a display based on Liquid Crystal Display (LCD) or Digital Light Processing (DLP) technology based on digital micromirror devices. Patterns are projected onto the liquid from the display device via optics. Because the display device is programmable, the patterns on the display can be changed for different layers.

Traditional light-curing 3D printing usually includes two printing technologies: top-down and bottom-up. In the free-liquid printing process, the photocurable resin is cured by a light source placed above the resin container and attached to the build platform. After the curing of the previous layer is completed, the build platform is lowered toward the resin container to prepare the next layer for curing. Each new solidified layer is formed on the upper surface of the three-dimensional object being built. In contrast, in the constrained liquid printing process, the photocurable resin is cured by a light source placed under a light-transmitting window at the bottom of the resin container, and each new cured layer is formed on the lower surface of the three-dimensional object being built. In the constrained liquid printing process, the build platform is lifted from the resin container and a peeling step is performed between each layer to peel the cured layer from the bottom of the resin container. Continuous Liquid Interface Production (CLIP) is a constrained liquid surface printing technology in which photocurable resin is cured through a light source placed under an oxygen-permeable window at the bottom of the resin container. The oxygen layer above the oxygen-permeable window (called the "dead space" or "inhibition layer") prevents liquid resin from adhering to the bottom of the resin container, so no peeling step is required, allowing for continuous exposure. However, this technology also has its limitations. For example, the dead zone is very sensitive to temperature, and small temperature fluctuations may cause printing failure.

US Patent 9,676,963 discloses a method of producing a three-dimensional object using a polymerizable liquid that includes a first photopolymerizable liquid component and a second curable component different from the first component. However, this method uses a mixture of multiple different components. When the two components are mixed, premature curing may occur, resulting in excessive viscosity of the mixture. Therefore, 3D printing must begin within a few hours of mixing the two components, otherwise the mixture becomes too viscous and unusable. This requires separate storage of different components, adding complexity to the production process.

Therefore, there is a need to provide better materials and production methods to use light-curing 3D printing technology to create three-dimensional objects.

This application describes methods and materials for producing three-dimensional objects using additive manufacturing technology. In some embodiments, materials useful for forming three-dimensional objects comprise a polymerizable liquid comprising: (a) a blocked or reactive blocked polyurethane prepolymer; (b) (optionally) a reactive diluent agent; (c) a blocked or reactive blocked curing agent; (d) a photoinitiator; and (e) (optional) a blocked or reactive blocked diisocyanate.

In some embodiments, the blocked or reactive blocked polyurethane prepolymer includes a polyisocyanate.

，其中A和R為獨立選擇的烴基，R’為NH或O，Z為包含反應型環氧基、烯基、炔基或硫醇端基的封閉基團。 In some embodiments, the blocked or reactive blocked polyurethane prepolymer has the structure of formula (A):

, where A and R are independently selected hydrocarbon groups, R' is NH or O, and Z is a blocking group containing a reactive epoxy, alkenyl, alkynyl or thiol end group.

In some embodiments, Z is 2-methyl-2-acrylic acid-2-[(1,1-dimethylethyl)amino]ethyl ester (t-BAEMA).

(A₃)，其中R₁、R₂和R₃為獨立選擇的直鏈或支鏈C1-C36烷基或亞烷基、烯基或亞烯基、芳基或亞芳基、雜芳基或亞雜芳基、環烷基或環烯基基團；Y₁和Y₂為獨立選擇的保護氨基或羥基的保護基團。 In some embodiments, the blocked or reactive blocked curing agent contained in the polymerizable liquid has the structure of formula (A1), formula (A2) or formula (A3):

(A ₃ ), wherein R ₁ , R ₂ and R ₃ are independently selected linear or branched C1-C36 alkyl or alkylene, alkenyl or alkenylene, aryl or arylene, heteroaryl Or a heteroarylene, cycloalkyl or cycloalkenyl group; Y ₁ and Y ₂ are independently selected protecting groups for protecting amino or hydroxyl groups.

In some embodiments, the protecting groups Y ₁ and Y ₂ have different structures.

In some embodiments, the blocked or reactive blocked curing agent includes an imino group that is a substituent resulting from the reaction of an aldehyde or ketone with an amine.

In some embodiments, the blocked or reactive blocked curing agent includes a urethane group that is a substituent derived from a carboxylic acid or carboxylate ester and an amine.

In some embodiments, the protecting group Y ₁ and/or Y ₂ further includes a photocurable group.

In some embodiments, Y ₁ and/or Y ₂ comprise photocurable groups comprising acrylate or methacrylate groups.

(A6)，其中R₄、R₅和R₆為獨立選擇的二烴基-氨基、C3-C36芳基或亞芳基、環烷基或環烯基基團；Y₁和Y₂為獨立選擇的保護氨基或羥基的保護基團；以及X包含一個可光固化基團。 In some embodiments, the blocked or reactive blocked curing agent contained in the polymerizable liquid has the structure of formula (A4), formula (A5) or formula (A6):

(A6), wherein R ₄ , R ₅ and R ₆ are independently selected dialkyl-amino, C3-C36 aryl or arylene, cycloalkyl or cycloalkenyl groups; Y ₁ and Y ₂ are independently selected a protecting group protecting an amino or hydroxyl group; and X contains a photocurable group.

The present application further provides a method for forming a three-dimensional object, which method includes: (a) providing a printing range defined by a building platform and a resin container containing a molding surface; (b) using the aforementioned A polymerizable liquid fills the printing range; (c) exposing the printing range to energy to form a solid printing intermediate substantially the same shape as the three-dimensional object; (d) (optional) cleaning the array printing intermediate; (e) Heating, microwave radiation, or using other methods to provide energy to the printing intermediate to form the three-dimensional object.

In some embodiments, the blocked or reactive blocked curing agent is present in the printing intermediate in a cured form.

In some embodiments, the formed three-dimensional object includes a blend polymer of polyurethane and polyacrylate, an interpenetrating polymer network, a semi-interpenetrating polymer network, or a sequential interpenetrating polymer network.

In some embodiments, the formed three-dimensional object includes a copolymer of polyurethane and polyacrylate.

The embodiments of the present application have other advantages and features. When combined with the examples in the following drawings, these advantages and features will be more obvious in the following detailed description and patent application scope: [Figure 1] is a curing mechanism A Schematic diagram of an embodiment using a dual-cure resin and a curing agent that does not participate in light curing.

[Fig. 2] is a schematic diagram of an embodiment of the curing mechanism B, which uses a dual-curing resin and a curing agent that participates in photocuring.

[Fig. 3] is a schematic diagram of an example of curing mechanism C using a dual-curing resin and a curing agent containing an asymmetric protecting group.

[Fig. 4] is a schematic diagram of an embodiment of the curing mechanism D using a dual curing resin and a curing agent further including a cross-linked curing site.

The drawings and the following description refer to preferred embodiments by way of illustration only. It should be noted that it will be readily apparent from the following discussion that alternative embodiments of structures and methods are possible alternatives without departing from the scope of the claims.

"Diisocyanate" and "polyisocyanate" are used interchangeably, and both can refer to aliphatic isocyanates, lipids, and lipids that contain multiple, or in some embodiments more than two, isocyanate (NCO) groups per molecule. Cyclic and aromatic isocyanates.

"Diols" and "polyols" are used interchangeably, and both refer to aliphatic alcohols that contain an average of multiple, or in some embodiments more than two, hydroxyl (OH) groups per molecule. Alicyclic alcohols and aromatic alcohols.

As used herein, the term "and/or" refers to any and all possible combinations of one or more of the listed components, as well as combinations lacking any component. For example, "A, B and/or C" means all of the following possibilities: A alone, B alone, C alone, A and B, A and C, B and C, A and B and C.

As used in this application, the term "visible light" refers to electromagnetic radiation with a wavelength of 400-700 nm, and "ultraviolet light" refers to electromagnetic radiation with a wavelength of 10-400 nm.

As used in this application, the term "stereolithography" or "photopolymerization" refers to the technique of photopolymerizing liquid resin in the presence of a photoinitiator to create three-dimensional objects.

As used herein, the terms "curing," "hardening," or "polymerization" refer to the process of forming monomers, oligomers, prepolymers, and/or polymers into a three-dimensional polymer network, which may or may not There may be no curing agent present.

The polymerizable liquids described in this application can be used in additive manufacturing to produce three-dimensional objects. In some embodiments, the polymerizable liquid includes the following components: (a) a blocked or reactive blocked polyurethane prepolymer; (b) (optional) a reactive diluent; (c) a blocked or reactive Closed curing agent; (d) a photoinitiator; and (e) (optional) a blocked or reactive blocked diisocyanate.

Polymerizable liquids: blocked or reactive blocked polyurethane prepolymers

，其中A和R為獨立選擇的烴基，R’為NH或O，Z為封閉基團。封閉基團Z與異氰酸酯(-NCO)基團之間的連接鍵是熱不穩定或其他方式不穩定的，因此在不穩定的條件下，此類連接鍵會發生斷裂從而暴露出異氰酸酯基團(-NCO)，從而使其自由的與其它組分發生後續反應。NCO封閉基團的實例包括但不限於：酚、壬基酚、吡啶醇、肟、硫代酚、硫醇、醯胺、環醯胺、醯亞胺、咪唑、咪唑啉、甲基乙基酮肟(methylethylketoxime,MEKO)、醇、ε-己內醯胺、吡唑、三唑、脒、羥酸酯或類似物。 In some embodiments, the blocked or reactive blocked polyurethane prepolymer comprises a compound having the following formula (A):

, where A and R are independently selected hydrocarbon groups, R' is NH or O, and Z is a blocking group. The bond between the blocking group Z and the isocyanate (-NCO) group is thermally or otherwise unstable, so under unstable conditions, such bond will break and expose the isocyanate group ( -NCO), leaving it free for subsequent reactions with other components. Examples of NCO blocking groups include, but are not limited to: phenol, nonylphenol, pyridinol, oxime, thiophenol, thiol, amide, cyclic amide, amide imine, imidazole, imidazoline, methyl ethyl ketone Oxime (methylethylketoxime, MEKO), alcohol, ε-caprolactam, pyrazole, triazole, amidine, hydroxy acid ester or the like.

。在這個實例中，大叔丁基的空間位阻造成封閉基團與異氰酸酯(-NCO)基團之間的連接鍵不穩定，加熱時可能會發生斷裂，因此在加熱條件下該連接鍵的斷裂使異氰酸酯(-NCO)基團可以與固化劑或者可聚合液體中的其它組分發生反應。在其它的一些實例中，封閉基團Z有可能為甲基丙烯酸叔戊基氨基乙基酯(tertiary penylaminoethyl methacrylate, TPAEMA)，甲基丙烯酸叔己基氨基乙基乙酯(tertiary hexylaminoethyl methacrylate,THAEMA)，甲基丙烯酸叔丁基氨基丙基酯(tertiary-butylaminopropyl methacrylate,TBAPMA)及其混合物。本領域具有通常知識者可以將(甲基)丙烯酸酯基團偶聯至上述已知的NCO封閉基團之上。 In some embodiments, the NCO blocking group Z may optionally include a reactive end group, so that the polyurethane prepolymer is reactively blocked. Examples of reactive end groups included by Z include, but are not limited to, epoxy, olefin, alkyne, thio, and vinyl groups. In one embodiment, blocking group Z is 2-methyl-2-acrylic acid-2-[(1,1-dimethylethyl)amino]ethyl ester (t-BAEMA), having the following molecular formula:

. In this example, the steric hindrance of the tert-butyl group causes the bond between the blocking group and the isocyanate (-NCO) group to be unstable and may break when heated. Therefore, the bond breaks under heating conditions. Isocyanate (-NCO) groups can react with curing agents or other components in the polymerizable liquid. In some other examples, the blocking group Z may be tertiary penylaminoethyl methacrylate (TPAEMA), tertiary hexylaminoethyl methacrylate (THAEMA), Tertiary-butylaminopropyl methacrylate (TBAPMA) and its mixtures. One of ordinary skill in the art can couple (meth)acrylate groups to the known NCO blocking groups described above.

In some embodiments, the blocked or reactive blocked polyurethane prepolymer includes a polyisocyanate oligomer resulting from the reaction of at least one diisocyanate and at least one polyol. Examples of diisocyanates include, but are not limited to, isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), methylenebis(phenyl isocyanate), MDI), toluene diisocyanate (TDI), naphthalene diisocyanate (NDI), methylene bis-cyclohexylisocyanate (HMDI). Examples of polyols include, but are not limited to, polyether polyols and polyester polyols, of which a specific example is poly(propylene oxide), PPO. Examples of such reactions are described in Journal of Applied Polymer Science 162, 1361 (1996) by Velankar, Pazos, and Cooper, the disclosure of which is incorporated herein by reference.

Polymerizable liquid: reactive diluent

In some embodiments, the reactive diluent can be a photocurable monomer or oligomer having photocurable groups. In some embodiments, the photocurable group may be a radically polymerizable group. In other embodiments, the photocurable group may be a cationically polymerizable group. In some embodiments, photocurable monomers or oligomers may include acrylates, methacrylates, olefins, N-vinyl, vinylamide, vinyl ether, vinyl ester, acrylamide, Methacrylamide, styrene, acrylic, epoxy, thio, 1,3-diene, vinyl halide, acrylonitrile, vinyl ester, maleimide, vinyl ether, and two of the above one or more combinations. In some embodiments, the photocurable monomer or oligomer can comprise epoxy/amine, epoxy/hydroxyl, oxygen Hetetane/amine, oxetane/alcohol. The reactive diluent reduces the viscosity of the photocurable polymer network and copolymerizes with the photocurable component in the polymerizable liquid.

In some embodiments, a reactive diluent may have one or more functionalities. Examples of reactive diluents may include, but are not limited to, 1,3-propanediol diacrylate and 1,3-propanediol dimethacrylate, 1,4-butanediol diacrylate and 1,4-butanediol Dimethacrylate, 1,5-pentanediol diacrylate and 1,5-pentanediol dimethacrylate, 1,6-hexanediol diacrylate and 1,6-hexanediol dimethyl acrylate, 1,7-heptanediol diacrylate and 1,7-heptanediol dimethacrylate, 1,8-octanediol diacrylate and 1,8-octanediol dimethacrylate Esters, trimethylolpropane triol triacrylate and trimethylolpropane triol trimethacrylate, ethoxylated trimethylolpropane triol triacrylate and ethoxylated trimethylolpropane Triol trimethacrylate, neopentyl glycol diacrylate and neopentyl glycol dimethacrylate, tripropylene glycol diacrylate and tripropylene glycol dimethacrylate, pentaerythritol triacrylate and pentaerythritol trimethacrylate Esters, and similar compounds. In some embodiments, the selection of certain reactive diluents or certain combinations of reactive diluents can increase the solubility of the photoinitiators used herein. In a preferred embodiment, monomers with low functionality are suitable for increasing the solubility of the photoinitiator in powder form.

Polymerizable liquid: photoinitiator

)、二烷基苯乙酮 (

)、羥烷基酮(

)、醯基氧化膦 (

)、氨基酮(

)、二苯甲酮 (

)、噻噸酮(

)、1，2二酮 (

)、1，7，7-三甲基-二環〔2.2.1〕庚烷-2，3-二酮 (

)、雙2，6-二氟-3-吡咯苯基二茂鈦(

)，其中R₁、R₂、R₃、R₄是任意數目的包括H、O、C、N、S在內的其它原子。在一些優選實施例中，本申請使用的光引發劑為苯甲醯基膦氧化物，包括TPO(

)、819(

)、TEPO (

)、819DW(

)。 The photoinitiator may be any photoinitiator capable of initiating a photocuring reaction together with the light source used to initiate the photocuring reaction. In some embodiments, the wavelength of the light used to initiate the photocuring reaction is 405 nm, and in other embodiments, the wavelength of the light used to initiate the photocuring reaction is 385 nm. Examples of photoinitiators include, but are not limited to, benzoin ether (

), dialkyl acetophenone (

), hydroxyalkyl ketone (

), acylphosphine oxide (

), aminoketone (

),Benzophenone(

), thioxanthone (

), 1,2 dione (

), 1,7,7-trimethyl-bicyclo[2.2.1]heptane-2,3-dione (

), bis-2,6-difluoro-3-pyrrophenyl titanocene (

), where R ₁ , R ₂ , R ₃ , and R ₄ are any number of other atoms including H, O, C, N, and S. In some preferred embodiments, the photoinitiator used in this application is benzylphosphine oxide, including TPO (

), 819(

), TEPO (

), 819DW(

).

Polymerizable liquids: blocked or reactive blocked diisocyanates

，其中R為烴基，Z為封閉基團，封閉基團Z的實例可包括但不限於酚、壬基酚、吡啶醇、肟、硫代酚、硫醇、醯胺、環醯胺、醯亞胺、咪唑、咪唑啉、甲基乙基酮肟(MEKO)、醇、ε-己內醯胺、吡唑、三唑、脒、羥酸酯或類似物。封閉基團Z與異氰酸酯(-NCO)基團之間的連接鍵是熱不穩定或其他方式不穩定的，因此在不穩定的條件下，此類連接鍵會發生斷裂從而暴露出異氰酸酯基團(-NCO)，從而使其自由的與其它組分發生後 續反應。在一些實施例中，NCO封閉基團Z可選的可以包含一個反應型端基，使二異氰酸酯被反應型封閉。Z包含的反應型端基的實例包括但不限於環氧、烯烴、炔烴、硫代、乙烯基基團。在一個實施例方案中，封閉基團Z為2-甲基-2-丙烯酸-2-〔(1，1-二甲基乙基)氨〕乙酯(t-BAEMA)，具有下列分子式：

。在這個實例中，大叔丁基的空間位阻造成封閉基團與異氰酸酯(-NCO)基團之間的連接鍵不穩定，加熱時可能會發生斷裂，因此在加熱條件下該連接鍵的斷裂使異氰酸酯(-NCO)基團可以與可聚合液體中的固化劑發生反應。在其它的一些實例中，封閉基團Z有可能為甲基丙烯酸叔戊基氨基乙基酯(TPAEMA)、甲基丙烯酸叔己基氨基乙基乙酯(THAEMA)、甲基丙烯酸叔丁基氨基丙基酯(TBAPMA)及其混合物。本領域具有通常知識者可以將(甲基)丙烯酸酯基團偶聯至上述已知的NCO封閉基團之上。 In some embodiments, the polymerizable liquid may optionally comprise a blocked or reactive blocked diisocyanate. In some embodiments, blocked or reactive blocked diisocyanates may include the following compounds:

, where R is a hydrocarbyl group and Z is a blocking group. Examples of the blocking group Z may include but are not limited to phenol, nonylphenol, pyridinol, oxime, thiophenol, thiol, amide, cycloamide, amide Amine, imidazole, imidazoline, methyl ethyl ketoxime (MEKO), alcohol, ε-caprolactam, pyrazole, triazole, amidine, hydroxy acid ester or the like. The bond between the blocking group Z and the isocyanate (-NCO) group is thermally or otherwise unstable, so under unstable conditions, such bond will break and expose the isocyanate group ( -NCO), leaving it free for subsequent reactions with other components. In some embodiments, the NCO blocking group Z may optionally include a reactive end group so that the diisocyanate is reactively blocked. Examples of reactive end groups included by Z include, but are not limited to, epoxy, olefin, alkyne, thio, and vinyl groups. In one embodiment, the blocking group Z is 2-methyl-2-acrylic acid-2-[(1,1-dimethylethyl)amino]ethyl ester (t-BAEMA), which has the following molecular formula:

. In this example, the steric hindrance of the tert-butyl group causes the bond between the blocking group and the isocyanate (-NCO) group to be unstable and may break when heated. Therefore, the bond breaks under heating conditions. Isocyanate (-NCO) groups can react with curing agents in polymerizable liquids. In other examples, the blocking group Z may be tert-pentylaminoethyl methacrylate (TPAEMA), tert-hexylaminoethyl methacrylate (THAEMA), tert-butylaminopropyl methacrylate ester (TBAPMA) and its mixtures. One of ordinary skill in the art can couple (meth)acrylate groups to the known NCO blocking groups described above.

Polymerizable liquids: blocked or reactive blocked curing agents

其中R₁、R₂和R₃為獨立選擇的直鏈或支鏈C1-C36烷基或亞烷基、烯基或亞烯基、芳基或亞芳基、雜芳基或亞雜芳基、環烷基或環烯基基團；Y₁和Y₂為獨立選擇的保護氨基或羥基的保護基團。在一些實施例中，Y₁和Y₂各自獨立選擇並具有不同的結構，在其它一些實施例中，Y₁和Y₂可以具有相同的結構。使用具有保護基團的固化劑可以幫助提高可聚合液體的穩定性。以這種方式，當不同組分混合儲存時，聚氨酯預聚體與固化劑之間不會過早的發生固化反應。該固 化反應可以控制為僅在保護基團被移除時才發生。 In some embodiments, the blocked or reactive blocked curing agent may comprise the structure of Formula (A1), Formula (A2), or Formula (A3):

Wherein R ₁ , R ₂ and R ₃ are independently selected linear or branched C1-C36 alkyl or alkylene, alkenyl or alkenylene, aryl or arylene, heteroaryl or heteroarylene , cycloalkyl or cycloalkenyl group; Y ₁ and Y ₂ are independently selected protecting groups for protecting amino or hydroxyl groups. In some embodiments, Y ₁ and Y ₂ are each independently selected and have different structures. In other embodiments, Y ₁ and Y ₂ may have the same structure. The use of curing agents with protecting groups can help improve the stability of polymerizable liquids. In this way, when different components are mixed and stored, there is no premature curing reaction between the polyurethane prepolymer and the curing agent. The curing reaction can be controlled to occur only when the protecting group is removed.

)、叔丁氧羰基(Boc

)、笏甲氧羰基(Fmoc，

)、烯丙氧羰基(Alloc，

)、三甲基矽乙氧羰基(Teoc，

)、甲(或乙)氧羰基(

)及其組合。在一些實施例 中，醯基基團可以包含鄰苯二甲醯基(Pht，

)、對甲苯磺醯基、 (Tos，

)、三氟乙醯基(Tfa，

)及其組合。在一些實施例 中，烷基基團可以包含三苯甲基(Trt，

)、2，4-二甲氧基苄基(Dmb，

)、對甲氧基苄基(PMB，

)、苄基(Bn，

)及其組合。在一些實施例中，氨基保護基團Y₁及/或Y₂也可以包含1-氯乙基氨基甲酸酯、4-甲氧基苯磺醯胺、乙醯胺、苄胺、苄氧基氨基甲酸酯、甲醯胺、氨基甲酸甲酯、三氟乙醯胺及其組合。氨基保護基團的更多實例可以在Protective Groups in Organic Chemistry,J.McOmie,Springer Science & Business Media,declaration 2012中獲得。 Examples of amino protecting groups Y ₁ and/or Y ₂ may include but are not limited to benzyloxycarbonyl (Cbz,

), tert-butoxycarbonyl (Boc

), Wat methoxycarbonyl (Fmoc,

), allyloxycarbonyl (Alloc,

), trimethylsilyl ethoxycarbonyl (Teoc,

), methyl (or ethyl)oxycarbonyl (

) and their combinations. In some embodiments, the acyl group can comprise phthalyl (Pht,

), p-toluenesulfonyl group, (Tos,

), trifluoroacetyl (Tfa,

) and their combinations. In some embodiments, the alkyl group may include trityl (Trt,

), 2,4-dimethoxybenzyl (Dmb,

), p-methoxybenzyl (PMB,

), benzyl (Bn,

) and their combinations. In some embodiments, the amino protecting groups Y ₁ and/or Y ₂ may also include 1-chloroethyl carbamate, 4-methoxybenzenesulfonamide, acetylamine, benzylamine, benzyloxy Carbamate, formamide, methyl carbamate, trifluoroacetamide and combinations thereof. More examples of amino protecting groups can be found in Protective Groups in Organic Chemistry, J. McOmie, Springer Science & Business Media, declaration 2012.

Examples of hydroxyl protecting groups Y ₁ and/or Y ₂ may include, but are not limited to, silicon ethers, benzyl ethers, substituted benzyl ethers, substituted methyl ethers, alkoxy methyl ethers, allyl ethers, aryl ethers, and the like. combination. In some embodiments, silicon ethers may include trimethylsilyl (TMS) ether, t-Butyldimethylsilyl (TBDMS) ether, tert-butyldiphenylsilyl (TBDPS) ether, Tri-isopropylsilyl (TIPS) ether and combinations thereof. In some embodiments, benzyl (Bn) ethers may include benzyl ethers of alkylhydroxyl groups, p-methoxybenzyl (PMB) ethers, trityl ethers, and combinations thereof. In some embodiments, alkoxymethyl ethers may include 2-tetrahydropyran (THP) ether, methoxymethyl (MOM) ether, a 2-ethoxyethyl (EE) ether , 2-Trimethylsilylethoxymethyl ((Trimethylsilyl)ethoxy]methyl, SEM) ether and combinations thereof. In some embodiments, the hydroxyl protecting groups Y ₁ and/or Y ₂ may include acetyl, benzyl, pivalyl, acetate, benzoate, pivalate, and combinations thereof. In some embodiments, the hydroxyl protecting groups Y ₁ and/or Y ₂ may also include 2,2,2-trichloroethyl carbonate, 2-methoxyethoxymethyl ether, 2-naphthylmethyl Methyl ether, 4-methoxybenzyl ether, acetate, benzoate, benzyl ether, benzyloxymethyl acetal, ethoxyethyl acetal, methoxymethyl acetal, methoxy Propyl acetal, methyl ether, tetrahydropyranyl acetal, triethylsilyl ether, triisopropylsilyl ether, trimethylsilyl ether, tert-butyldiphenylmethyl Silyl ethers, acetylides, benzaldehyde acetals, carbonates, benzaldehyde acetals, di-tert-butyldioxetane and combinations thereof. More examples of hydroxyl protecting groups can be found in Protective Groups in Organic Chemistry, J. McOmie, Springer Science & Business Media, declaration 2012.

In some embodiments, when the curing agent is a protected amine or imine, the protecting groups Y ₁ and/or Y ₂ may include carboxylic acid or anhydride groups (an example of an anhydride is di-tert-butyl dicarbonate (Boc ₂ O)), a chloride group (examples are described in U.S. Patent Nos. 5,231,147, 3,639,657, and 4,430,489, the disclosures of which are incorporated herein by reference), aldehyde or ketone groups (examples are described in U.S. Patent Nos. 3,932,357 Described in , the disclosure of which is incorporated herein by reference), complexes of metal salts (examples of such metal salts are described in US patent application US 20070213497A1, diaminodiphenylmethane-NaCl, which The disclosures of are incorporated into this application by reference).

In some embodiments, the protecting groups Y ₁ and/or Y ₂ may further include a photocurable group. Examples of the photocurable group may include but are not limited to acrylate, methacrylate, olefin, N - Vinyl, acrylamide, methacrylamide, styrene, epoxy, thio, 1,3-diene, vinyl halide, acrylonitrile, vinyl ester, maleimide, vinyl ether and A combination of two or more of the foregoing. In some embodiments, the photocurable groups may include epoxy/amine, epoxy/hydroxy, oxetane/amine, oxetane/alcohol. In some embodiments, Y ₁ and/or Y ₂ are independently selected and have different structures, for example, one protecting group includes a photocurable end group and the other protecting group does not include such an end group.

In some embodiments, the protecting groups Y ₁ and/or Y ₂ may include a photocurable methacrylate group. In some embodiments, the protecting groups Y ₁ and/or Y ₂ are independently selected and have the same or different structures. One of ordinary skill in the art can couple (meth)acrylate groups to the above-mentioned known protecting groups.

(當偶聯至氨基或羥基起保護作用時酮基中的氧原子被取代)，其中Ry可以是： In some embodiments, the unsubstituted protecting groups Y ₁ and/or Y ₂ may include compounds of the following formula:

(The oxygen atom in the ketone group is substituted when coupled to the amino or hydroxyl group for protection), where Ry can be:

；在另一個實例中，未被取代的保護基團Y₁及/或Y₂ 可以包含下式的化合物：

，其中n為範圍在1-10內的整數。 (1) Straight chain or branched hydrocarbon group. In some embodiments, the number of carbon atoms in the hydrocarbon group may be in the range of 1-10; in one example, the unsubstituted protecting groups Y ₁ and/or Y ₂ may include compounds of the following formula:

; In another example, the unsubstituted protecting groups Y ₁ and/or Y ₂ may include compounds of the following formula:

, where n is an integer in the range 1-10.

，其中n為範圍在1-10內的整數，R為直鏈或支鏈的烴基。 (2) Repeating units containing alkoxy groups. In some embodiments, the number of repeating units may range from 1 to 10. In one example, the unsubstituted protecting groups Y ₁ and/or Y ₂ may include compounds of the following formula:

, where n is an integer in the range of 1-10, and R is a linear or branched hydrocarbon group.

(3) Repeating units containing ester groups;

(4) Repeating units containing siloxane groups; or

(5) Repeating units containing thioether groups.

其中CAT為相轉移催化劑。可在此處使用的相轉移催化劑的實例可以包含胺鹽(例如苄基三乙基氯化銨(benzyltriethylammonium,TEBA)或溴化銨(ammonium bromide,TEBA-Br)、苄基三甲基氯化銨、溴化銨或氫氧化銨(Triton B)、四丁基氯溴化銨、碘化銨或氫氧化銨、十六烷基三甲基溴化銨、氯化銨、四正己基溴化銨、氯化銨或類似物)、冠醚(如15冠5、18冠6、二苯並18冠6)、鹽(例如溴化三丁基phosph、溴化乙基三苯基phosph、氯化四苯基phosph或類似物)。在一些實施例中，相轉移催化劑可以與試劑例如二環己基碳二亞胺(dicyclohexylcarbodiimide,DCC)一起使用以促進酯化反應。 The following reaction formula shows some examples of preparation methods of the above-mentioned protecting groups Y ₁ and/or Y ₂ :

CAT is a phase transfer catalyst. Examples of phase transfer catalysts that may be used here may include amine salts such as benzyltriethylammonium chloride (TEBA) or ammonium bromide (TEBA-Br), benzyltrimethyl chloride Ammonium, ammonium bromide or ammonium hydroxide (Triton B), tetrabutylammonium chloride bromide, ammonium iodide or ammonium hydroxide, cetyltrimethylammonium bromide, ammonium chloride, tetra-n-hexyl bromide Ammonium, ammonium chloride or similar), crown ethers (such as 15-crown 5, 18-crown 6, dibenzo-18-crown 6), salts (such as tributylphosph bromide, ethyltriphenylphosph bromide, chlorine tetraphenylphosph or similar). In some embodiments, a phase transfer catalyst can be used with a reagent such as dicyclohexylcarbodiimide (DCC) to promote the esterification reaction.

In some embodiments, the unsubstituted protecting groups Y ₁ and/or Y ₂ can be methyl isobutyl ketone (MIBK), in which the oxygen atom plays a protective role when coupled to the amino or hydroxyl group. time to be replaced.

其中R₄、R₅和R₆為獨立選擇的二烴基-氨基、C3-C36芳基或亞芳基、環烷基或環烯基基團；Y₁和Y₂為獨立選擇的保護氨基或羥基的保護基團；X包含一個可光固化基團；Y₁及/或Y₂為獨立選擇的氨基或羥基保護基團。在一些實施例中，Y₁和Y₂獨立選擇並具備不同結構；而在另一些實施例中，Y₁和Y₂可以具備相同結構。在一些實施例中，固化劑可以包含一個交聯固化部位，使其能夠在雙重固化流程中使熱塑性聚氨酯鏈段與UV-固化的交聯聚丙烯酸酯部分交聯，以形成丙烯酸酯^-氨基甲酸酯共聚物網路。與丙烯酸酯部分與聚氨酯鏈段未發生共聚的丙烯酸酯^-氨基甲酸酯體系相比，這種共聚物網路不僅保持了高伸長率和彈性，同時使網路更加牢固耐用。在一些實施例中，R₄、R₅和R₆可以含有多於三個的取代位置。 In some embodiments, the blocked or reactive blocked curing agent has the structure of formula (A4), formula (A5) or formula (A6):

Wherein R ₄ , R ₅ and R ₆ are independently selected dihydrocarbyl-amino, C3-C36 aryl or arylene, cycloalkyl or cycloalkenyl groups; Y ₁ and Y ₂ are independently selected protected amino or Protective group for hydroxyl; X contains a photocurable group; Y ₁ and/or Y ₂ are independently selected amino or hydroxyl protecting groups. In some embodiments, Y ₁ and Y ₂ are independently selected and have different structures; while in other embodiments, Y ₁ and Y ₂ can have the same structure. In some embodiments, the curing agent may include a cross-linking cure site that enables it to cross-link thermoplastic polyurethane segments with UV-cured cross-linked polyacrylate moieties in a dual cure process to form acrylate ^- urethane segments Acid ester copolymer network. Compared with the acrylate ^- urethane system in which the acrylate part and the polyurethane segment are not copolymerized, this copolymer network not only maintains high elongation and elasticity, but also makes the network stronger and more durable. In some embodiments, R ₄ , R ₅ and R ₆ may contain more than three substitution positions.

，作為一個公式(A₅)的實例，R₅為二乙氨基，X為甲基丙烯酸2-羥丙酯，Y₁和Y₂為甲基異丁基酮(MIBK)(其中的氧原子當偶聯至氨基起保護作用時被取代)。在這個實例中，該固化劑可以由下式所示的反應機制產生：

除了可以使用二亞乙基三胺(diethylenetriamine,DETA)合成上述固化劑之外，本領域具有通常知識者可以使用其它類型的胺化合物來製備具有交聯固化位置的固化劑，實例可以包括但不限於三亞乙基四胺(triethylenetetramine,TETA)和N-(4-氨基環己基)-1，4-環己二胺。 In some embodiments, the curing agent may have the structure of the following formula:

, as an example of formula (A ₅ ), R ₅ is diethylamino, X is 2-hydroxypropyl methacrylate, Y ₁ and Y ₂ are methyl isobutyl ketone (MIBK) (the oxygen atom is Substituted when coupled to the amino group for protection). In this example, the curing agent can be produced by the reaction mechanism shown in the following formula:

In addition to the use of diethylenetriamine (DETA) to synthesize the above-mentioned curing agents, those with ordinary knowledge in the art can use other types of amine compounds to prepare curing agents with cross-linked curing sites. Examples may include but not Limited to triethylenetetramine (TETA) and N-(4-aminocyclohexyl)-1,4-cyclohexanediamine.

Some embodiments of the present application provide a method for producing a three-dimensional object using the polymerizable liquid described in the present application, the method comprising the following steps:

(1) Provide a printing range defined by a build platform and a resin container containing the molding surface;

(2) Fill the printing range with a polymerizable liquid, which liquid contains: (a) a blocked or reactive blocked polyurethane prepolymer; (b) (optional) a reactive diluent; (c) ) a blocked or reactive blocked curing agent; (d) a photoinitiator; and (e) (optional) a blocked or reactive blocked diisocyanate.

(3) Expose the printing range to form a solid printing intermediate that is substantially the same shape as the three-dimensional object; in some embodiments, a blocked or reactive blocked curing agent is included in the printing intermediate in an uncured form In other embodiments, the blocked or reactive blocked curing agent can participate in the photocuring reaction during the exposure process through the photocurable end group, so the curing agent is included in the printing intermediate in a cured form. middle.

(4) (Optional) Clean the printing intermediate;

(5) Heating, microwave radiation, exposure to water vapor or using other methods to provide energy to the printing intermediate through the second curing step to form the three-dimensional object. Under heating, microwave radiation, humid conditions or other known conditions, the blocking group of the polyurethane prepolymer and the protecting group of the curing agent are cleaved, which means that the blocking/protecting group and its blocked/protected part The bonds break, exposing the enclosed/protected area for further solidification. Depending on the different designs of the curing agents described in this application, this application may have different curing mechanisms. Non-limiting examples of these curing mechanisms are described further below.

A. Dual-curing resin materials using curing agents that do not participate in the light-curing reaction

In some embodiments, protecting groups Y ₁ and Y ₂ are independently selected amino or hydroxyl protecting groups and do not contain a photocurable group. In these embodiments, the printing intermediate includes the curing agent in an uncured form when the polymerizable liquid containing such curing agent is exposed to light to form the printing intermediate. After photocuring, under heating, microwave radiation, humid conditions or other known suitable conditions, the protecting groups Y ₁ and Y ₂ are cleaved to expose the protected amino or hydroxyl groups for further curing. An example of this solidification mechanism is shown in Figure 1.

In the example shown in Figure 1, a polyurethane prepolymer blocked with ethylenically unsaturated blocking groups undergoes a photocuring reaction together with an (optional) reactive diluent to form cross-linked networks (i.e., solid arrays). printing intermediate) containing a protected curing agent in an uncured form. In the curing mechanism shown in Figure 1, the curing agent is a diamine compound. After the photocuring reaction, under heating, microwave radiation, moist conditions or other known suitable conditions, the blocking group blocking the isocyanate group is cleaved to expose it for further curing. Also under the same conditions, the protecting group protecting the amino group is also cleaved, exposing the amino group and reacting with the isocyanate group to form a network structure. The network structure includes the following components: (a) linear thermoplastic polyurethane, polyurea and/or Copolymers thereof; (b) cross-linked thermosetting polyurethanes, polyureas and/or copolymers thereof; (c) UV-cured polyacrylates (linear or cross-linked); (d) Combination of the aforementioned components. The network may be an interpenetrating polymer network (IPN), semi-interpenetrating or pseudo IPN, or sequential IPN. However, in these examples, the polyurethane portion of the network is not covalently bonded to the polyacrylate portion of the network. In some embodiments, the network also includes other components, such as a copolymer of a deprotected curing agent and a reactive diluent, as well as unreacted photoinitiator or the like.

B. Dual-curing resin materials using curing agents that participate in photocuring reactions

In some embodiments, protecting groups Y ₁ and Y ₂ are independently selected amino or hydroxyl protecting groups and also include photocurable groups. In these embodiments, the printing intermediate includes the curing agent in a cured form when the polymerizable liquid containing such curing agent is exposed to light to form the printing intermediate. An example of this solidification mechanism is shown in Figure 2.

In the example shown in Figure 2, a polyurethane prepolymer blocked with ethylenically unsaturated blocking groups is used together with a curing agent also blocked with ethylenically unsaturated groups, and (optionally) a reactive diluent. A photocuring reaction is carried out to form a cross-linked network (i.e., a solid printing intermediate), which contains a protected curing agent in a cured form. In the curing mechanism shown in Figure 2, the curing agent is a diamine compound, and both ends are protected by photocurable groups. In these embodiments, because the curing agent in the printing intermediate exists in a cured form, the printing intermediate has better mechanical properties and a post-processing process that is easier to operate. After the photocuring reaction, under heating, microwave radiation, moist conditions or other known suitable conditions, the blocking group blocking the isocyanate group is cleaved to expose it for further curing. Also under the same conditions, the protecting group protecting the amino group is also cleaved, exposing the amino group and reacting with the isocyanate group to form a network structure. The network structure includes the following components: (a) linear thermoplastic polyurethane, polyurea and/or Copolymers thereof; (b) cross-linked thermosetting polyurethane, polyurea and/or copolymers thereof; (c) UV-cured polyacrylate (linear or cross-linked); (d) combinations of the aforementioned components. The network may be an interpenetrating polymer network (IPN), semi-interpenetrating or pseudo IPN, or sequential IPN. However, in these examples, the polyurethane portion of the network is not covalently bonded to the polyacrylate portion of the network. combine. In some embodiments, the network also includes other components, such as a copolymer of a deprotected curing agent and a reactive diluent, as well as unreacted photoinitiator or the like.

C. Dual-cure resin materials using curing agents with asymmetric protective groups

In some embodiments, the protecting groups Y ₁ and Y ₂ are independently selected amino or hydroxyl protecting groups and have different structures. In some examples, one of the protecting groups includes a photocurable end group and the other protecting group does not include a photocurable end group. In these embodiments, the printing intermediate includes the curing agent in a cured form when the polymerizable liquid containing such curing agent is exposed to light to form the printing intermediate. An example of this solidification mechanism is shown in Figure 3.

In the example shown in Figure 3, a polyurethane prepolymer blocked by an ethylenically unsaturated blocking group is combined with a curing agent that is also blocked by an ethylenically unsaturated group on only one end, and (optional) reactive dilution The photocuring reaction is carried out together with the printing agent to form a cross-linked network (i.e., a solid printing intermediate), which contains a protected curing agent in a cured form. In the curing mechanism shown in Figure 3, the curing agent is a diamine compound with only one end protected by a photocurable group. In these embodiments, because the curing agent in the printing intermediate exists in a cured form, the printing intermediate has better mechanical properties and a post-processing process that is easier to operate. After the photocuring reaction, under heating, microwave radiation, moist conditions or other known suitable conditions, the blocking group blocking the isocyanate group is cleaved to expose it for further curing. Also under the same conditions, the protecting group protecting the amino group is also cleaved, exposing the amino group and reacting with the isocyanate group to form a network structure. The network structure includes the following components: (a) linear thermoplastic polyurethane, polyurea and/or Copolymers thereof; (b) cross-linked thermosetting polyurethane, polyurea and/or copolymers thereof; (c) UV-cured polyacrylate (linear or cross-linked); (d) combinations of the aforementioned components. The network may be an interpenetrating polymer network (IPN), semi-interpenetrating or pseudo IPN, or sequential IPN. However, in these examples, the polyurethane portion of the network is not covalently bonded to the polyacrylate portion of the network. Compared with the above-mentioned curing mechanism B, curing mechanism C provides another possible option for adjusting the composition of three-dimensional objects, thereby achieving the purpose of adjusting the physical properties of three-dimensional printed objects. in some In embodiments, the network also includes other components, such as a copolymer formed by a deprotected curing agent and a reactive diluent, as well as unreacted photoinitiator or the like.

D. Dual-cured resin materials using curing agents with cross-linked curing sites

In some embodiments, protecting groups Y ₁ and Y ₂ are independently selected amino or hydroxyl protecting groups but do not contain a photocurable group. The curing agent also contains a cross ^- linking cure site, things. In these embodiments, the printing intermediate includes the curing agent in a cured form when the polymerizable liquid containing such curing agent is exposed to light to form the printing intermediate. An example of this solidification mechanism is shown in Figure 4.

In the example shown in Figure 4, a polyurethane prepolymer blocked by ethylenically unsaturated blocking groups is combined with a curing agent that is also blocked by ethylenically unsaturated groups at the crosslinking cure site, and (optionally) The reactive diluent undergoes a photocuring reaction together to form a cross-linked network (i.e., a solid printing intermediate), which contains the protected curing agent in a cured form. In addition to the cross-linked curing site that enables the curing agent to participate in the photocuring reaction, the curing agent also contains one or more protected amino groups or hydroxyl groups. Once the amino groups or hydroxyl groups are deprotected, they can be combined with the deblocked polyurethane. The prepolymers react to produce polyurethane. In the curing mechanism shown in Figure 4, the curing agent is a diamine compound containing two protected amino groups and an ethylenically unsaturated cross-linking curing site. In these embodiments, because the curing agent in the printing intermediate exists in a cured form, the printing intermediate has better mechanical properties and a post-processing process that is easier to operate. After the photocuring reaction, under heating, microwave radiation, moist conditions or other known suitable conditions, the blocking group blocking the isocyanate group is cleaved to expose it for further curing. Also under the same conditions, the protecting group protecting the amino group is also cleaved, exposing the amino group and reacting with the isocyanate group to form a network structure. The network structure includes the following components: (a) linear thermoplastic polyurethane, polyurea and/or Copolymers thereof; (b) Cross-linked thermosetting polyurethanes, polyureas and/or copolymers thereof; (c) UV-cured polyacrylates (linear or cross-linked); (d) Copolymers of polyurethanes, polyureas and/or copolymers thereof with UV-cured polyacrylates and (e) the aforementioned components in combination. Compared with the previous curing mechanism, this curing mechanism covalently combines the polyurethane part of the network and the polyacrylate part of the network, so the three-dimensional object formed not only maintains good extensibility, but also provides better strength and durability. In some embodiments, the network also includes other components, such as a copolymer of a deprotected curing agent and a reactive diluent, as well as unreacted photoinitiator or the like.

The polymerizable liquid disclosed in the present application can be implemented using commonly known light-curing 3D printing technologies, such as stereolithography (SLA), digital light processing (DLP) and material jetting (MJ). Examples are used to create three-dimensional objects. In some embodiments, an additive manufacturing method for forming a three-dimensional object of the present application includes the following steps: (a) providing a printing range defined by a building platform and a resin container containing a molding surface ; (b) filling the printing range with the polymerizable liquid described in the present application; (c) exposing the printing range to energy to form a solid printing intermediate that is substantially the same shape as the three-dimensional object; (d) ) (optional) cleaning the printing intermediate; (e) heating, microwave radiation, or using other methods to provide energy to the printing intermediate to form the three-dimensional object.

In some embodiments, in the methods described herein, the polymerizable liquid includes a blocked or reactive blocked polyurethane prepolymer in a range of 1% to 99% by weight and a blocked or reactive blocked polyurethane prepolymer in a range of 1% to 99% by weight. Blocking or reactive blocking curing agent.

In some embodiments, the printing intermediate is first produced by photocuring in a first curing step using a DLP printer. In some embodiments, the wavelength used to initiate photocuring is 405 nm, and in other embodiments, the wavelength used to initiate photocuring is 385 nm. Anything that can be used to initiate photocuring Photoinitiators that initiate the photocuring reaction together with the reactive light source can be used. In some preferred embodiments, light with a wavelength exceeding 400 nm is used to initiate photocuring, with a wavelength of 405 nm being particularly used. In these preferred embodiments, photoinitiator 819 is used to initiate light with wavelengths in excess of 400 nm because 819 photoinitiator has stronger absorption in the long wavelength UV range within the phosphine oxide photoinitiator family.

After the printing intermediate is formed, the printing intermediate may optionally be cleaned and dried. In some embodiments, the cleaning solution may be aqueous, containing water and surfactants. In some embodiments, the water can be deionized water. Examples of surfactants may include, but are not limited to, anionic surfactants (e.g., sulfates, sulfonates, carboxylates, and phosphates), cationic surfactants, zwitterionic surfactants, nonionic surfactants, or the like Objects, and their combinations. Common examples include, but are not limited to, sodium stearate, linear alkylbenzene sulfonate, lignosulfonate, fatty alcohol ethoxylate, alkylphenol ethoxylate or the like, and combinations thereof.

After an optional cleaning step, the printed intermediate is further cured to form the final printed 3D object. The second-step curing can be performed by heating, humidification, microwave radiation, or other suitable energy sources, which can cause the blocking and protecting groups in the polymerizable liquid to cleave to initiate the second-step curing. In some embodiments, the second step of curing is thermal curing. In some embodiments, the thermal curing temperature ranges from room temperature to 200 C, and the thermal curing time ranges from 0.5 to 200 h. In some embodiments, the second step of curing may be heating under humidified conditions.

Embodiments of the present application are explained in detail in the following non-limiting examples:

Example 1 Synthesis of Reactive Blocked Polyurethane Prepolymers

Add 200 g of anhydrous polybutylene glycol (PTMG 1000) into a 500 mL three-neck flask equipped with an overhead stirrer, nitrogen protection and a thermometer. Then, 67.2g of hexamethylene diisocyanate (HDI) was added to the flask and stirred into a uniform solution with PTMG for 10 min. Then, 140 μL of catalyst dibutyltin dilaurate (DBTL) was added and reacted at 70°C for 3 h. After 3 h, 75 g of 2-methyl-2-acrylic acid-2-[(1,1-dimethylethyl)amino]ethyl ester (tertiary-butylaminoethyl methacrylate, TBAEMA) was gradually added. The temperature was then set to 50°C and 100 ppm hydroquinone was added. The reaction was continued for 10 h to obtain product A as a clear liquid. The reaction formula is as follows:

Example 2 Synthesis of Reactive Blocked Isocyanates

Add 88.9g isophorone diisocyanate (IPDI) into a 500mL three-neck flask with an overhead stirrer, nitrogen protection and thermometer, add 140μL catalyst DBTL and 75g TBAEMA, 100ppm hydroquinone and react at 70°C After 3h, a transparent liquid product B was obtained. The reaction formula is as follows:

Example 3 One-pot synthesis of reactive blocked polyurethane prepolymers and reactive blocked isocyanates

200 g of anhydrous polybutylene glycol (PTMG 1000) was added to a 500 mL three-neck flask equipped with an overhead stirrer, nitrogen protection, and a thermometer. Then 134.4g HDI was added to the flask and stirred into a homogeneous solution with PTMG for 10 min, then 240 μL of catalyst DBTL was added and reacted at 70°C 3 h. After 3h, 255g TBAEMA was gradually added. The temperature was then set to 50°C and 100 ppm hydroquinone was added. The reaction was continued for 10 hours to obtain a transparent liquid product C, which was a mixture of reactive blocked polyurethane prepolymer and reactive blocked diisocyanate.

Example 4 Synthesis of Carboxylic Acid-Protected Polyamines

Under nitrogen, 504.6g of 2-methylpentamethylenediamine and 295.4g of sebacic acid were charged and gradually heated to 245°C. The reaction temperature was kept above 230°C for about 10 hours. After vacuuming to remove traces of moisture, the molten product D was discharged and cooled under nitrogen in a desiccator. Once completely cooled and solidified, the resin is broken into medium-sized pieces and ground into a powder using a centrifugal mill. The ground polyamide was then passed through a 250 μ screen to remove coarse particles. The powdered resin is then packaged under nitrogen for future use or further use.

Example 5 DLP 3D printing test using the products of Examples 1, 2 and 4

Mix polyethylene glycol (600) acrylate, 1,4-butanediol diacrylate and photoinitiator (TPO) at room temperature, stir for 30 minutes using a rotor mixer, rotate at 500r/min, to obtain a transparent liquid . To the above mixture, add products A, B and D, stir for 40 minutes using a rotor mixer at a rotation speed of 1500 r/min until a transparent liquid is obtained. Add the blue slurry and use a rotor mixer to stir for 30 minutes at a speed of 2000r/min to obtain the required 3D printing material. The viscosity of this light-curing 3D printing material is 4400cps at room temperature. After 3 months of storage at room temperature, the viscosity was 4500cps, an increase of only 2%, proving its good long-term storage stability. The exact amounts of each reactant used to produce the final printed material are listed in the table below. Use a Form 1+SLA 3D printer to print the 3D printing material, with a laser power of 5mw and a scanning speed of 3m/s to obtain a printed spline. The sample was placed in an oven at 140°C and heated for 10 h to complete thermal curing. The tensile test was conducted in accordance with the ASTM D412 standard. The tensile strength was 36.7±1.3MPa and the elongation at break was 352±25%.

Example 6 Synthesis of MIBK protected curing agent DMDC

Put 3,3-dimethyl-4,4-diaminodicyclohexylmethane (DMDC) and excess methyl isobutyl ketone (MIBK) (molar ratio 1:4) into the reactor, The reaction was heated and stirred in an oil bath. First, the temperature is raised to 130°C to form a reflux reaction. After 2 hours of reaction, the temperature is raised to 150-160°C to continue the reflux reaction. The reaction time is about 4 hours. After the reaction is completed, purify under reduced pressure at 120°C for 2-3 hours to remove product water and excess methyl isobutyl ketone to obtain light yellow transparent liquid E with a yield of about 95%. The reaction formula is as follows:

Example 7 DLP 3D printing test using the products of Examples 3 and 6

Dissolve photoinitiator TPO in 1,6-hexanediol dimethacrylate and polyethylene glycol (600) dimethacrylate (polyethylene glycol (600) dimethacrylate, PEG (600) DMA), then add product C and MIBK-terminated ketimine curing agent DMDC-MIBK to the solution, and then mix further Prepare the printing liquid evenly. Pour the evenly mixed printing liquid into the material box, and use LEAP technology to print a dog-bone-shaped test sample according to ASTM D412 mold C. After cleaning with the cleaning solution, place the sample at 25°C and 65% Leave it in a humid environment for 12 hours, then heat cure at 120°C for 8 hours. Use a CTM tensile machine to test the mechanical properties of the cured elastomer splines according to ASTM standard D412. According to the ASTM D412 standard, the tensile strength is 20MPa and the elongation at break is 310%.

Example 8 Boc ₂ Synthesis of O-Protected Curing Agent PACM

Add 120g water and 9.14g (0.0435mol) 4,4 ^- diaminodicyclohexylmethane (PACM) into a 250mL single-neck flask, stir for 20min, and add 20.9g di-tert-butyl dicarbonate (Boc ₂ O) (0.0957mol) , reacted at room temperature (30-35°C), the reactants in the flask turned into white emulsion, and a few bubbles were generated on the wall of the bottle. After 3 hours of reaction, a large amount of white precipitate appeared, indicating that the reaction was basically completed. Use a vacuum funnel to filter the reaction product and remove the water phase. Wash the filtered solid three times with 200 ml of distilled water and filter. The obtained white solid material is vacuum dried at 90°C for 4 hours to obtain white powdery solid product F, with a yield of about 50%. . The reaction formula is as follows:

Example 9 DLP 3D printing test using the products of Examples 3 and 8

Dissolve the photoinitiator TPO in lauryl methacrylate (LMA) and polyethylene glycol (600) dimethacrylate (PEG (600) DMA), and then add product C to the solution. Then further mix evenly to prepare the printing liquid. Pour the evenly mixed printing liquid into the material box, and use LEAP technology to print a dog-bone-shaped test sample according to ASTM D412 mold C. After cleaning with the cleaning solution, place the sample at 120°C for heat curing for 8 hours. . Use a CTM tensile machine to test the mechanical properties of the cured elastomer splines according to ASTM standard D412. According to the ASTM D412 standard, the tensile strength is 18MPa and the elongation at break is 280%.

Example 10 DLP 3D printing test using the product of Example 3 and diaminodiphenylmethane sodium chloride complex

Mix polyethylene glycol (600) methacrylate, 2-ethylhexyl acrylate, diaminodiphenylmethane sodium chloride complex curing agent and photoinitiator TPO at room temperature, and stir using a rotor mixer. 30min, rotating speed 500r/min, to obtain a transparent liquid. To the above mixture, add product C and stir for 40 minutes using a rotor mixer at a rotation speed of 1500 r/min until a transparent liquid is obtained. Add the red slurry and use a rotor mixer to stir for 30 minutes at a speed of 2000r/min to obtain the required 3D printing material. The viscosity of this light-curing 3D printing material is 3400cps at room temperature. After three months of storage at room temperature, the viscosity is 3700cps, an increase of only 8%, proving its good long-term storage stability. The exact amounts of each reactant used to produce the final printed material are listed in the table below. Use a Form 1+SLA 3D printer to print the 3D printing material, with a laser power of 3.5mw and a scanning rate of 3.5m/s to obtain a printed spline. The sample was placed in a 140°C oven and heated for 10 hours to complete thermal curing. The tensile test was conducted in accordance with the ASTM D412 standard. The tensile strength was 25.3±2.7MPa and the elongation at break was 452±15%.

Example 11 Synthesis of photocurable ketone protective curing agent

Mix 3,3-dimethyl-4,4-diaminodicyclohexylmethane (DMDC) and excess 3,3-dimethyl-4-oxopentyl methacrylate (molar ratio of substances 1: 2), put it into the reactor, heat it up in the oil bath and stir the reaction. Raise the temperature to 150-160°C and maintain reflux reaction. The reaction time is about 8 hours. After the reaction is completed, purify under reduced pressure at 120°C for 2-3 hours to remove the product water and excess 3,3-dimethyl-4-oxopentyl methacrylate to obtain a light yellow transparent liquid H with a yield of 85%. about. The reaction formula is as follows:

Example 12 DLP 3D printing test using the products of Examples 3 and 11

Mix polyethylene glycol (600) methacrylate and 1,6-hexanediol dipropylene at room temperature. Mix the acrylic acid ester and photoinitiator 819, stir for 30 minutes using a rotor mixer, and rotate at 500 r/min to obtain a transparent liquid. To the above mixture, add products C and D, and stir for 40 minutes using a rotor mixer at a rotation speed of 1500 r/min until a transparent liquid is obtained. Add the white slurry and use a rotor mixer to stir for 30 minutes at a speed of 2000r/min to obtain the required 3D printing material. The viscosity of this light-curing 3D printing material is 3500cps at room temperature. After three months of storage at room temperature, the viscosity was 3800cps, an increase of only 8%, proving its good long-term storage stability. The exact amounts of each reactant used to produce the final printed material are listed in the table below. Use a Form 1+SLA 3D printer to print the 3D printing material, with a laser power of 8mw and a scanning speed of 2.5m/s to obtain a printed spline. The sample was placed in a 120°C oven and heated for 15 hours to complete thermal curing. The tensile test was conducted in accordance with the ASTM D412 standard. The tensile strength was 22.2±3.3MPa and the elongation at break was 283±12%.

Example 13 Photocurable Boc ₂ Synthesis of O-Protected Curing Agent PACM

Add 120g water and 9.14g (0.0435mol) 4,4-diaminodicyclohexylmethane (PACM) to the reaction vessel, stir for 20 minutes, add 30.5g ((dioxy(carbonyl)bis(oxy))bis(2) -Methylpropane-2,1-substituent)bis(2-methacrylic acid), react at room temperature (30-35°C), the reactant in the flask turns into a white emulsion, and a few bubbles are generated at the side of the bottle, react for 5 hours Afterwards, a large amount of white precipitate appeared, indicating that the reaction was basically completed. Use a vacuum funnel to filter the reaction product, remove the aqueous phase, and wash the filtered solid three times with 200 mL distilled water and filter. The obtained white solid material was vacuum dried at 90°C for 4 hours to obtain White powdery solid product G, yield is about 60%. The reaction formula is as follows:

Example 14 DLP 3D printing test using the products of Examples 1 and 13

Mix isobornyl methacrylate, 2-ethylhexyl acrylate, product G and photoinitiator TPO at room temperature, and stir for 30 minutes using a rotor mixer at a rotation speed of 500 r/min to obtain a transparent liquid. To the above mixture, add product A and stir for 40 minutes using a rotor mixer at a rotation speed of 1500 r/min until a transparent liquid is obtained. Add the red slurry and use a rotor mixer to stir for 30 minutes at a speed of 2000r/min to obtain the required 3D printing material. The viscosity of this light-curing 3D printing material is 2200cps at room temperature. After three months of storage at room temperature, the viscosity was 2400cps, an increase of only 9%, proving its good long-term storage stability. The exact amounts of each reactant used to produce the final printed material are listed in the table below. Use a Form 1+SLA 3D printer to print the 3D printing material, with a laser power of 3.5mw and a scanning rate of 3.5m/s to obtain a printed spline. The sample was placed in a 140°C oven and heated for 10 hours to complete thermal curing. The tensile test was conducted in accordance with the ASTM D412 standard. The tensile strength was 55.3±2.7MPa and the elongation at break was 102±11%.

Example 15 Synthesis of DMDC protected by acetyl n-propyl methacrylate

Put 3,3-dimethyl-4,4-diaminodicyclohexylmethane (DMDC) and excess acetyl n-propyl methacrylate (molar ratio 1:2) into the reactor, and place it in an oil bath Stir the reaction at medium-high temperature. Raise the temperature to 150-160°C and maintain reflux reaction. The reaction time is about 8 hours. After the reaction is completed, purify under reduced pressure at 120°C for 2-3 hours to remove product water and excess acetyl n-propyl methacrylate to obtain a light yellow transparent liquid I with a yield of about 85%. The reaction formula is as follows:

Example 16 DLP 3D printing test using the product of Example 15

Dissolve the photoinitiator TPO, light stabilizer 292, and antioxidant 1135 in lauryl methacrylate (LMA) and polyethylene glycol (600) dimethacrylate (PEG (600)) on a Thinky ^TM mixer. DMA), and then add the tert-butylaminoethyl methacrylate (TBAEMA)-terminated polyurethane prepolymer (TBAEMA-IPDI-PTMO2000-IPDI-TBAEMA) and the product I obtained in Example 15 to the solution, Then use a Thinky ^TM mixer to further mix evenly to prepare the printing liquid. Use the Thinky ^TM mixer to mix the printing liquid evenly, pour it into the material box, and use LEAP technology to print the dog bone-shaped test sample according to ASTM D412 mold C. After cleaning with the cleaning solution, place the sample in Soak in water at 60°C for 30 minutes, then heat cure at 120°C for 8 hours. Use a CTM tensile machine to test the mechanical properties of the cured elastomer splines according to ASTM standard D412. The exact amounts of each reactant used to produce the final printed material are listed in the table below along with the mechanical properties of the test specimens.

Example 17 Synthesis of ketones used to protect polyamines

，其中n=3，攪拌加熱，反應溫度控制在80-120℃之間。4-8h後停止反應，過濾除去 NaCl，所得濾液，30-60℃減壓蒸餾蒸出未反應原料及溶劑，然後在80-130℃溫度下精餾得到無色透明產物。這個實施例中，阻聚劑可以是受阻酚類、芳胺類、醌類或類似物。溶劑可以是苯類(苯、甲苯)烷烴類(環己烷、正庚烷、石油醚或類似物)。相轉移催化劑可以是苄基三乙基氯化銨(TEBA)。 In a three-necked flask equipped with a stirrer, condenser and thermometer, add 1 mol of dry methacrylic acid sodium salt, polymerization inhibitor (0.1%-0.3% quality), 3-6 mol of solvent, and phase transfer catalyst (0.1%-0.5 % quality) and 2-6 mol of ketones containing chlorine groups, for example,

, where n=3, stir and heat, and the reaction temperature is controlled between 80-120°C. The reaction was stopped after 4-8 hours, and NaCl was removed by filtration. The resulting filtrate was distilled under reduced pressure at 30-60°C to evaporate the unreacted raw materials and solvent, and then rectified at 80-130°C to obtain a colorless and transparent product. In this embodiment, the polymerization inhibitor may be hindered phenols, aromatic amines, quinones or the like. Solvents may be benzene (benzene, toluene) alkanes (cyclohexane, n-heptane, petroleum ether or the like). The phase transfer catalyst may be benzyltriethylammonium chloride (TEBA).

Example 18 Another example of a ketone used to protect polyamines

，其中n=3，甲基丙烯酸1mol，溶劑二氯甲烷8-10mol，催化劑0.03-0.1mol 4-二甲氨基吡啶(dimethylaminopyridine,DMAP)，攪拌均勻，降低溫度至0-20℃，加入二環己基碳二亞胺(dicyclohexylcarbodiimide,DCC)，控制反應溫度不超過40℃，反應4-10h，停止反應。產物過濾除去產生的不溶物二環己基脲，濾液使用1mol/L酸清洗分液；分出油相，使用飽和碳酸氫鈉清洗分液；分出油相，減壓蒸餾除去溶劑，得淡黃色澄清粗產品，粗產品經減壓精餾得到無色透明餾分，即為產物。 Add 1.1-3.5 mol of alcohol with carbonyl group into the reactor, for example:

, where n=3, 1 mol of methacrylic acid, 8-10 mol of solvent dichloromethane, 0.03-0.1 mol of catalyst 4-dimethylaminopyridine (DMAP), stir evenly, lower the temperature to 0-20°C, and add bicyclic For dicyclohexylcarbodiimide (DCC), control the reaction temperature not to exceed 40°C, react for 4-10 hours, and then stop the reaction. The product is filtered to remove the insoluble substance dicyclohexylurea produced. The filtrate is washed and separated using 1mol/L acid. The oil phase is separated and washed and separated with saturated sodium bicarbonate. The oil phase is separated and the solvent is distilled under reduced pressure to obtain a light yellow color. The crude product is clarified, and the crude product is distilled under reduced pressure to obtain a colorless and transparent fraction, which is the product.

Example 19 Curing agent with cross-linking curing site

Add 1 mol of diethylenetriamine (DETA) and 1-3 mol of methyl isobutyl ketone to the reactor, and remove the water produced by azeotrope in a solvent (such as benzene, toluene, xylene or an alkane solvent). Carry out the reaction. After the water in the water separator reaches the calculated value, lower the temperature and reduce the pressure to remove the solvent and excess ketone to obtain the ketimine of diethylenetriamine; add 100-500ppm polymerization inhibitor to the product, and then add 1 mol of an epoxy acrylate compound, such as glycidyl methacrylate (GMA), is heated to 60-100°C for reaction to produce a modified UV-reactive ketimine product J. The reaction formula is as follows:

Example 20 DLP 3D printing test using the product of Example 19

Dissolve the photoinitiator TPO, light stabilizer 292, and antioxidant 1135 in lauryl methacrylate (LMA) and polyethylene glycol (600) dimethacrylate (PEG (600) DMA) on a Thinky ^TM mixer. ), then add the tert-butylaminoethyl methacrylate (TBAEMA)-terminated polyurethane prepolymer (TBAEMA-IPDI-PTMO2000-IPDI-TBAEMA) and the product J obtained in Example 19 to the mixture, and then Use a Thinky ^TM mixer to further mix and prepare the printing liquid. Use the Thinky ^TM mixer to mix the printing liquid evenly, pour it into the material box, and use LEAP technology to print the dog bone-shaped test sample according to ASTM D412 mold C. After cleaning with the cleaning solution, place the sample in Soak in water at 60°C for 30 minutes, then heat cure at 120°C for 8 hours. The mechanical properties of the cured elastomer splines were tested using an Instron tensile machine according to ASTM standard D412. According to the ASTM D412 standard, the tensile strength is 22MPa and the elongation at break is 340%.

Example 21 Synthesis of Curing Agents with Asymmetric Protecting Groups

Add 1 mol of 3,3-dimethyl-4,4-diaminodicyclohexylmethane (DMDC) and 1 mol of methyl isobutyl ketone to the reactor, and add 1 mol of methyl isobutyl ketone to the reactor. ), remove the produced water azeotropically, and after generating the calculated amount of water, obtain the MIBK-protected amine DMDC at one end; add 1 mol of the product obtained in Example 17 to the system, and continue the azeotropic reaction with water; after generating the calculated amount of water, The solvent was distilled off under reduced pressure to obtain product K.

Example 22 DLP 3D printing test using the product of Example 21

Dissolve the photoinitiator TPO, light stabilizer 292, and antioxidant 1135 in lauryl methacrylate (LMA) and polyethylene glycol (600) dimethacrylate (PEG (600) DMA) on a Thinky ^TM mixer. ), then add the tert-butylaminoethyl methacrylate (TBAEMA)-terminated polyurethane prepolymer (TBAEMA-IPDI-PTMO2000-IPDI-TBAEMA) and the product K obtained in Example 21 to the mixture, and then Use a Thinky ^TM mixer to further mix and prepare the printing liquid. Use the Thinky ^TM mixer to mix the printing liquid evenly, pour it into the material box, and use LEAP technology to print the dog bone-shaped test sample according to ASTM D412 mold C. After cleaning with the cleaning solution, place the sample in Soak in water at 60°C for 30 minutes, then heat cure at 120°C for 8 hours. The mechanical properties of the cured elastomer splines were tested using an Instron tensile machine according to ASTM standard D412. According to the ASTM D412 standard, the tensile strength is 28MPa and the elongation at break is 640%.

Claims (18)

A polymerizable liquid that can be used to form three-dimensional objects using additive manufacturing technology, the polymerizable liquid comprising: (a) a blocked or reactive blocked polyurethane prepolymer; (b) (optional) a reactive dilution agent; (c) a blocked or reactive blocked curing agent, the curing agent includes a protecting group for protecting amino or hydroxyl groups and a photocurable group; (d) a photoinitiator; and (e) (optional) ) a blocked or reactive blocked diisocyanate. For example, in the polymerizable liquid of claim 1, the blocked or reactive blocked polyurethane prepolymer includes a polyisocyanate. For example, the polymerizable liquid of item 1 of the patent application, wherein: the blocked or reactive blocked polyurethane prepolymer has the structure of formula (A):

Wherein A and R are independently selected hydrocarbon groups, R' is NH or O, and Z is a blocking group including a reactive epoxy group, alkenyl group, alkynyl group or thiol end group. For example, the polymerizable liquid in item 3 of the patent application, wherein: Z is 2-methyl-2-acrylic acid-2-[(1,1-dimethylethyl)amino]ethyl ester (tert-butyl aminoethyl methacrylate, t-BAEMA). For example, the polymerizable liquid of item 1 of the patent application, wherein: the blocked or reactive blocked curing agent has a structure of formula (A1) (A2) or (A3):

Wherein R ₁ , R ₂ and R ₃ are independently selected linear or branched C1-C36 alkyl or alkylene, alkenyl or alkenylene, aryl or arylene, heteroaryl or heteroarylene , a cycloalkyl or cycloalkenyl group; and Y ₁ and Y ₂ are independently selected protecting groups for protecting amino or hydroxyl groups. For example, the polymerizable liquid of item 5 of the patent application, wherein: Y ₁ and Y ₂ have different structures. For example, the polymerizable liquid of item 5 of the patent application, wherein: the blocked or reactive blocked curing agent includes an imino group, and the imino group is a substituent generated by the reaction of an aldehyde or ketone with an amine. For example, the polymerizable liquid of item 5 of the patent application, wherein: the blocked or reactive blocked curing agent includes a carbamate group, and the carbamate group is a carboxylic acid or a carboxylic acid ester and an amine. resulting substituents. For example, the polymerizable liquid of item 5 of the patent application wherein: Y ₁ and/or Y ₂ further includes a photocurable group. For example, the polymerizable liquid of claim 9, wherein the photocurable group includes an acrylate or methacrylate group. For example, the polymerizable liquid in item 1 of the patent application scope, wherein: the blocked or reactive blocked curing agent has a structure of formula (A4), formula (A5) or formula (A6):

Wherein R ₄ , R ₅ and R ₆ are independently selected dihydrocarbyl ^- amino, C3-C36 aryl or arylene, cycloalkyl or cycloalkenyl groups; Y ₁ and Y ₂ are independently selected protected amino or a protecting group for hydroxyl; and X includes a photocurable group. For example, in the polymerizable liquid of claim 11, the blocked or reactive blocked curing agent includes an imino group, and the imino group is a substituent generated by the reaction of an aldehyde or ketone with an amine. Such as the polymerizable liquid of item 11 of the patent application, wherein: the blocked or reactive blocked curing agent includes a urethane group, and the urethane group is a carboxylic acid or a carboxylic ester and an amine. resulting substituents. For example, the polymerizable liquid of claim 11, wherein: X includes an acrylate or methacrylate group. A method of forming a three-dimensional object, the method comprising: (a) providing a printing range defined by a building platform and a resin container including a molding surface; (b) using the patent application scope 1 to The polymerizable liquid of any one of 14 fills the printing range; (c) exposing the printing range to energy to form a solid printing intermediate that is substantially the same shape as the three-dimensional object; (d) (Optional) cleaning the printing intermediate; (e) heating, microwave radiation, or using other methods to provide energy to the printing intermediate to form the three-dimensional object. Such as the method of claim 15, wherein: the blocked or reactive blocked curing agent exists in the printing intermediate in a cured form. Such as the method of claim 15, wherein: the three-dimensional object includes a blended polymer of polyurethane and polyacrylate, an interpenetrating polymer network, a semi-interpenetrating polymer network, or a sequential interpenetrating polymer network road. For example, the method in Item 15 of the patent application scope includes: The three-dimensional object includes a copolymer of polyurethane and polyacrylate.