One-component moisture-heat multi-curing photosensitive resin and preparation method thereof

Abstract

The application relates to the technical field of light-cured materials, and particularly discloses a single-component moisture-heat multi-curing photosensitive resin and a preparation method thereof. The single-component moisture-heat multi-curing photosensitive resin comprises the following components in parts by weight: 40-70 parts of a hindered urea polyurethane acrylate, 10-30 parts of a multifunctional acrylate component, 10-40 parts of a monomer diluent, 1-5 parts of a photoinitiator and 3-15 parts of a latent curing agent; the mass ratio of the hindered urea polyurethane acrylate to the latent curing agent is 6.5:1-15:1. The hindered urea polyurethane acrylate and the latent curing agent are compounded, and the mass ratio of the two is controlled, so that the system can perform a subsequent curing reaction under a moisture-heat condition, and meanwhile, the multifunctional acrylate component, the monomer diluent and the photoinitiator form a light-curing system, thereby achieving the effects of reducing carbon dioxide gas generation and improving the compactness of a cured entity.

Description

Technical Field

[0001] This application relates to the field of photocurable materials technology, and more specifically, to a single-component, hygrothermal, multi-curable photosensitive resin and its preparation method. Background Technology

[0002] Photopolymer 3D printing is an additive manufacturing technology that utilizes photosensitive resin to polymerize and cure under specific wavelengths of light, forming a three-dimensional solid through layer-by-layer exposure. Common molding methods include SLA, DLP, and LCD. Photosensitive resin is a key material in photopolymer 3D printing, and its composition and curing method directly affect the printing process and the structural properties of the cured part. Photosensitive resin typically uses acrylate oligomers, reactive monomers, and photoinitiators as its main components, achieving rapid molding by initiating the polymerization of acrylate double bonds through light irradiation. However, when relying solely on photopolymerization, the reactive groups in the system are difficult to fully transform due to factors such as oxygen inhibition and limited chain segment movement in the later stages of crosslinking. Therefore, a combination of photopolymerization and subsequent curing is usually used to further improve the degree of curing.

[0003] In existing technologies, to achieve further crosslinking after photocuring, epoxy, isocyanate, or latent thermal reactive groups can be introduced into the photosensitive resin, so that the resin is first rapidly shaped by light irradiation, and then the subsequent crosslinking is completed by heat curing or humid heat curing. In existing single-component humid heat curing resins, blocked isocyanates can be used to participate in the subsequent curing reaction under humid heat conditions. However, in a humid heat environment, isocyanate groups may also react directly with water and produce carbon dioxide. The gas produced is prone to forming bubbles inside the cured entity, resulting in a non-dense internal structure of the cured entity. Summary of the Invention

[0004] To address the issue that isocyanate groups may react directly with water to produce carbon dioxide in humid and hot environments, and the resulting gas can easily form bubbles inside the cured entity, leading to a non-dense internal structure, this application provides a single-component humid and hot multi-curing photosensitive resin and its preparation method.

[0005] This application provides a single-component, hygrothermal, multi-curing photosensitive resin and its preparation method, employing the following technical solution: In a first aspect, this application provides a single-component, hygrothermal, multi-curing photosensitive resin, employing the following technical solution: A single-component, hygrothermal, multi-curing photosensitive resin comprises the following components in parts by weight: 40-70 parts of hindered urea polyurethane acrylate, 10-30 parts of multifunctional acrylate component, 10-40 parts of monomer diluent, 1-5 parts of photoinitiator, 0.5-3 parts of colorant, and 3-15 parts of latent curing agent; wherein the mass ratio of hindered urea polyurethane acrylate to latent curing agent is 6.5:1 to 15:1.

[0006] By adopting the above technical solution, the system can undergo subsequent curing reactions under humid and hot conditions by using hindered urea polyurethane acrylate and latent curing agent in combination and controlling their mass ratio. This reduces the chance of side reactions between the reactive groups in the hindered urea polyurethane acrylate and water. At the same time, the system is combined with multifunctional acrylate components, monomer diluents and photoinitiators to form a photocuring system. Therefore, the system achieves the effect of reducing carbon dioxide gas production and improving the internal density of the cured entity. This solves the problem that carbon dioxide is generated by the reaction of isocyanate groups with water in humid and hot environments, which leads to the formation of bubbles and non-density in the cured entity.

[0007] Preferably, the hindered urea polyurethane acrylate has any one of the following structures: TBAEMA-HMDI-PTMG2000-HMDI-TBAEMA; TBAEMA-IPDI-PTMG1000-IPDI-TBAEMA; Among them, TBAEMA is ethyl 2-(tert-butylamino)methacrylate, HMDI is 4,4'-dicyclohexylmethane diisocyanate, IPDI is isophorone diisocyanate, and PTMG2000 and PTMG1000 are polytetrahydrofuran diols with number average molecular weights of 2000 and 1000, respectively.

[0008] By adopting the above technical solution, by using the two hindered urea polyurethane acrylate structures mentioned above, and by compounding them with multifunctional acrylate components, monomer diluents and latent curing agents, the resulting photosensitive resin can form a curing system with different mechanical properties, while maintaining a multi-curing mode that combines photocuring and post-humidification curing.

[0009] Preferably, the hindered urea polyurethane acrylate is prepared by the following method: PTMG and diisocyanate were stirred and reacted at 20–40 °C for 0.5–2 h, then 500–2000 ppm of organometallic catalyst was added, and the temperature was raised to 60–80 °C for 1–3 h until the NCO content was below 5.5%. After cooling, TBAEMA is added dropwise. After the addition is complete, the mixture is kept at 70-80℃ for 1-3 hours until the NCO reaction endpoint is reached, thus obtaining the hindered urea polyurethane acrylate.

[0010] By adopting the above technical solution, the reaction between PTMG, diisocyanate and TBAEMA is controlled in stages, and the NCO content is used as the basis for controlling the reaction process. This allows the obtained hindered urea polyurethane acrylate to be stably used in the formulation of subsequent photosensitive resin systems. When it is compounded with latent curing agents and photocuring components, a single-component system with both photocuring and humid heat curing capabilities can be formed, providing the corresponding main resin structure for subsequent multiple curing processes.

[0011] Preferably, the PTMG includes PTMG2000 or PTMG1000, the diisocyanate includes HMDI or IPDI, and the organometallic catalyst includes at least one of dibutyltin dilaurate, stannous octoate, di(dodecyl sulfide)dibutyltin, and dibutyltin diacetate.

[0012] By adopting the above technical solution and selecting PTMG, diisocyanate and organometallic catalysts as described above, hindered urea polyurethane acrylates with different structures can be prepared according to the corresponding reaction routes, and formed with photocurable components and latent curing agents to form corresponding resin systems, so that the obtained single-component photosensitive resin can take into account both photocuring and subsequent hygrothermal curing.

[0013] Preferably, the multifunctional acrylate component includes at least one of trifunctional to hexafunctional polyurethane acrylate, polyester acrylate and epoxy acrylate.

[0014] By adopting the above technical solution, trifunctional to hexafunctional acrylate components are combined with hindered urea polyurethane acrylate, monomer diluent and photoinitiator, so that the system forms a photocurable crosslinked structure under light irradiation, and provides a pre-formed polymer network for subsequent hygrothermal curing, so that photocuring and hygrothermal post-curing can be carried out sequentially to form a multi-curing system.

[0015] Preferably, the monomer diluent includes at least one of isobornyl acrylate, acrylmorpholine, 2-phenoxyethyl acrylate, ethoxyethoxyethyl acrylate, tetrahydrofurfuryl acrylate, and laurate.

[0016] By adopting the above technical solution, the monomer diluent is compounded with hindered urea polyurethane acrylate, multifunctional acrylate components and photoinitiator, so that each photocurable component can jointly form a uniform photosensitive resin system and participate in the photocuring process; at the same time, it coexists with the latent curing agent in the single-component system, so that the resulting resin can continue to be cured by humid heat after the photocuring process is completed.

[0017] Preferably, the photoinitiator includes at least one of acylphosphine oxide photoinitiators, α-hydroxy ketone photoinitiators, α-amino ketone photoinitiators, benzoin ether photoinitiators, benzophenone photoinitiators, thioxanthone photoinitiators, and anthraquinone photoinitiators.

[0018] By adopting the above technical solution, the photoinitiator is combined with hindered urea polyurethane acrylate, multifunctional acrylate components and monomer diluent, so that the resin can undergo photocuring reaction under light irradiation and form an initial molded structure; on this basis, subsequent reaction between latent curing agent and hindered urea polyurethane acrylate is carried out for hydrothermal curing, thereby realizing the continuous process of photocuring and hydrothermal curing.

[0019] Preferably, the latent curing agent includes at least one of aldimine, ketimine, and oxazolidine.

[0020] By adopting the above technical solution, the latent curing agent and the hindered urea polyurethane acrylate are pre-dispersed in the photosensitive resin. Under normal temperature storage conditions, the degree of premature reaction of the active curing component can be reduced, while under humid heat conditions, active groups that participate in subsequent curing can be generated and further react with the reactive groups in the hindered urea polyurethane acrylate, thereby taking into account both the storage stability of the single-component system and the ability to cure after humid heat.

[0021] Secondly, this application provides a method for preparing a single-component, hygrothermal, multi-curing photosensitive resin, employing the following technical solution: A method for preparing a single-component, moisture-heat-cured, multi-stage photosensitive resin, applied to the aforementioned single-component, moisture-heat-cured, multi-stage photosensitive resin, includes the following steps: By weight, hindered urea polyurethane acrylate, multifunctional acrylate component, monomer diluent, photoinitiator, colorant and latent curing agent are mixed evenly to obtain the single-component hygrothermal multi-curing photosensitive resin.

[0022] By adopting the above technical solution, the hindered urea polyurethane acrylate, the photocuring component and the latent curing agent are pre-mixed to form a uniform single-component system. There is no need to mix the resin and the active curing agent on site before use. This allows the photocuring reaction component and the subsequent hygrothermal curing reaction component to coexist in the same resin system, thereby taking into account both photocuring printing and subsequent hygrothermal curing, and extending the continuous printing working time of the resin.

[0023] Thirdly, this application provides the application of the aforementioned single-component, hygrothermal, multi-curing photosensitive resin in photopolymerization 3D printing, employing the following technical solution: Based on the above-mentioned application of single-component hygrothermal multi-curing photosensitive resin in photocuring 3D printing, the single-component hygrothermal multi-curing photosensitive resin is used for photocuring 3D printing to obtain a photocured molded part, and the photocured molded part is subjected to hygrothermal post-curing; the temperature of the hygrothermal post-curing is 100-120℃, the relative humidity is ≥85%, and the time is 2-6h.

[0024] By adopting the above technical solution, the photosensitive resin is first formed into a photocurable part with a predetermined shape by photocuring 3D printing, and then it is subjected to humid heat curing at 100-120℃ and relative humidity ≥85% to further react the latent curing system inside the part, thereby improving the curing degree and mechanical properties of the part.

[0025] In summary, this application has the following beneficial effects: 1. Because this application uses hindered urea polyurethane acrylate and a latent curing agent in combination and controls their mass ratio, the system can carry out subsequent curing reactions under humid and hot conditions, reducing the chance of side reactions between the reactive groups in the hindered urea polyurethane acrylate and water. At the same time, it combines multifunctional acrylate components, monomer diluents and photoinitiators to form a photocuring system. Therefore, it achieves the effect of reducing carbon dioxide gas generation and improving the internal density of the cured entity, solving the problem that isocyanate groups react with water to generate carbon dioxide in a humid and hot environment, resulting in the formation of bubbles and non-dense structure inside the cured entity.

[0026] 2. This application uses hindered urea polyurethane acrylate and latent curing agent to form a single-component system, so that the reaction components required for subsequent curing can coexist in the photosensitive resin in advance. Under normal temperature storage conditions, it is not easy for the system to undergo reactions that cause rapid thickening or gelation. Therefore, it can improve the storage stability of the photosensitive resin and extend the continuous printing working window.

[0027] 3. The photosensitive resin of this application can first be rapidly molded by light curing, and then further extended and cross-linked inside the molded part by moisture heat curing, thereby further improving the degree of cross-linking of the polymer network and the mechanical properties of the molded part. Attached Figure Description

[0028] Figure 1 This is a diagram illustrating the synthesis of hindered urea polyurethane acrylate provided in this application; Figure 2 This is a diagram illustrating the hydrothermal curing mechanism provided in this application; Figure 3 This is a flowchart of a method for preparing a single-component, hygrothermal, multi-curing photosensitive resin provided in this application. Detailed Implementation

[0029] The present application will be further described in detail below with reference to the accompanying drawings and embodiments.

[0030] Technical Concept: Photopolymer 3D printing typically uses acrylic photosensitive resins for rapid prototyping. However, relying solely on photopolymerization, reactive groups in the system are difficult to fully transform due to factors such as oxygen inhibition and limited chain segment movement in the later stages of crosslinking. Therefore, existing technologies usually introduce a thermosetting reaction to improve the curing degree of the molded part. Existing resins combining photopolymerization and thermosetting are mostly in a two-component form, storing the photosensitive resin and thermosetting agent separately and mixing them before use. However, after the two components are mixed, they gradually react, causing the resin viscosity to continuously increase and shortening the usable time. To extend the resin's usability window, existing technologies further propose a single-component moisture-curing system, using water to participate in the subsequent curing reaction to achieve secondary crosslinking. However, during the research process, the applicant discovered that when isocyanate groups are present in the moisture-curing system, the isocyanate groups may also react directly with water to produce carbon dioxide. The generated gas is easily trapped inside the molded part and forms bubbles, resulting in a non-dense internal structure of the cured entity. Therefore, how to reduce the direct reaction between isocyanate groups and water to produce carbon dioxide while achieving single-component storage and moisture-curing is the technical problem that this application needs to solve.

[0031] Based on this, the applicant studied the combination of photocuring reaction system and humid heat post-curing reaction system, and found that by introducing hindered urea polyurethane acrylate and latent curing agent into the photosensitive resin and controlling their compatibility, the photosensitive resin can first complete rapid molding through photopolymerization of acrylate groups, and then be further cured under humid heat conditions. Under humid heat conditions, the latent curing agent generates active groups that can participate in subsequent curing and react with the corresponding reactive groups in the hindered urea polyurethane acrylate, thereby reducing the chance of isocyanate groups directly reacting with water, reducing carbon dioxide production, and further extending and cross-linking the molded parts. At the same time, the hindered urea polyurethane acrylate and latent curing agent can coexist in the same resin system in advance, so that the resulting photosensitive resin forms a single-component system and completes the multiple curing process of photocuring and humid heat post-curing while maintaining a long printing working window.

[0032] Unless otherwise specified, all experimental methods used below are conventional methods. All materials, reagents, methods, and instruments used, unless otherwise specified, are conventional materials, reagents, methods, and instruments in this field, which can be obtained commercially or prepared according to literature methods by those skilled in the art.

[0033] Please see the appendix Figure 1 Preparation Example 1: Hindered Urea Polyurethane Acrylate: Brief Synthesis of PUA1: TBAEMA-HMDI-PTMG2000-HMDI-TBAEMA Add 0.5 mol PTMG2000 (water content < 500 ppm; if it exceeds this, dehydration is required beforehand) and 1 mol HMDI to a reaction flask and stir at 30°C for 1 h. Then add 1000 ppm dibutyltin dilaurate and slowly raise the temperature to 70°C and maintain this temperature for 2 h. Check the NCO content (slightly less than 5.5%). Cool down to 50°C. Once the NCO content is within the acceptable range, slowly add TBAEMA dropwise using a dropping funnel. Start stirring in the reaction flask and control the heating rate at 2°C / min, ensuring the temperature does not exceed 75°C. After the addition is complete, maintain the temperature at 75°C for 2 h and check the NCO content. If NCO ≤ 0, the reaction is terminated. Pour the solution into a light-proof sample bottle for later use.

[0034] Preparation Example 2: Brief Synthesis of Hindered Urea Polyurethane Acrylate: PUA2: TBAEMA-IPDI-PTMG1000-IPDI-TBAEMA Add 0.5 mol PTMG1000 (water content < 500 ppm; if it exceeds this, dehydration is required beforehand) and 1 mol IPDI to a reaction flask and stir at 30°C for 1 h. Then add 1000 ppm dibutyltin dilaurate and slowly raise the temperature to 70°C and maintain this temperature for 2 h. Check the NCO content (slightly less than 5.5%). Cool down to 50°C. Once the NCO content is within the acceptable range, slowly add TBAEMA dropwise using a dropping funnel. Start stirring in the reaction flask and control the heating rate at 2°C / min, ensuring the temperature does not exceed 75°C. After the addition is complete, maintain the temperature at 75°C for 2 h and check the NCO content. If NCO ≤ 0, the reaction is terminated. Pour the solution into a light-proof sample bottle for later use.

[0035] The photoinitiators of this application include, but are not limited to, acylphosphine oxides (TPO-L / TPO / TMO / 819), α-hydroxy ketones (184 / 2959 / 1173), α-amino ketones (369), benzoin ethers, benzophenones such as benzophenone (BP) and its derivatives, thioxanthones such as ITX, DETX, etc., anthraquinones such as 2-ethylanthraquinone, etc., or combinations thereof.

[0036] To better understand the above technical solutions, the technical solutions of this application will be clearly and completely described below in conjunction with the embodiments.

[0037] Please see the appendix Figures 1 to 3 The following is a further description with reference to the embodiments: Example 1: Preparation of a single-component, moisture-cured, multi-stage photosensitive resin: 2 parts of photoinitiator (TPO) were dissolved in 20 parts of EOEOEA, then 10 parts of DPGDA and 1 part of color paste were added, followed by 60 parts of PUA1 and stirring until homogeneous. 8.22 parts of aldehyde-imine (hydrolysis equivalent 240) were added as curing agent at room temperature, and the mixture was stirred for 1 hour until completely homogeneous. The UV resin was then prepared.

[0038] 3D printing: DLP oxygen permeation machine printing, exposure energy 5mW / cm² 2 With a layer thickness of 0.1 mm and a single-layer exposure time of 4 s, tensile test specimens for elastomers and tear resistance test specimens were printed, and residual resin on the specimen surface was cleaned.

[0039] Post-curing: The sample was placed in an oven at 110℃ for 4 hours with a humidity of >85% to complete the preparation.

[0040] Example 2: Preparation of a single-component, hygrothermal, multi-curing photosensitive resin: 2 parts of photoinitiator (TPO) were dissolved in 20 parts of EOEOEA, then 10 parts of DPGDA and 1 part of color paste were added, followed by 60 parts of PUA1 and stirring until homogeneous. At room temperature, 6.17 parts of aldehyde-imine (hydrolysis equivalent 240) were added as curing agent, and the mixture was stirred for 1 hour until completely homogeneous. The UV resin preparation was completed.

[0041] 3D printing: DLP oxygen permeation machine printing, parameters: exposure energy 5mW / cm² 2 With a layer thickness of 0.1 mm and a single-layer exposure time of 4 s, tensile test specimens for elastomers and tear resistance test specimens were printed, and residual resin on the specimen surface was cleaned.

[0042] Post-curing: The sample was placed in an oven at 110℃ for 4 hours and the humidity was >85% to complete the preparation.

[0043] Example 3: Preparation of a single-component, hygrothermal, multi-curable photosensitive resin: 2 parts of photoinitiator (TPO) were dissolved in 20 parts of EOEOEA, then 10 parts of DPGDA and 1 part of color paste were added, followed by 60 parts of PUA1 and stirring until homogeneous. At room temperature, 4.11 parts of aldehyde-imine (hydrolysis equivalent 240) were added as curing agent, and the mixture was stirred for 1 hour until completely homogeneous. The UV resin was then prepared.

[0044] 3D printing: DLP oxygen permeation machine printing, exposure energy 5mW / cm² 2 With a layer thickness of 0.1 mm and a single-layer exposure time of 4 s, tensile test specimens for elastomers and tear resistance test specimens were printed, and residual resin on the specimen surface was cleaned.

[0045] Post-curing: The sample was placed in an oven at 110℃ for 4 hours with a humidity of >85% to complete the preparation.

[0046] Example 4: Preparation of a single-component, hygrothermal, multi-curing photosensitive resin: 2 parts of photoinitiator (TPO) were dissolved in 27 parts of ACMO, then 10 parts of NPGDA and 1 part of color paste were added, followed by 50 parts of PUA2 and stirring until homogeneous. At room temperature, 3.67 parts of curing agent aldehyde-imide (hydrolysis equivalent 160) were added and stirred for 1 hour until completely mixed. The UV resin was then prepared.

[0047] 3D printing: DLP oxygen permeation machine printing, parameters: exposure energy 5mW / cm²2 With a layer thickness of 0.1 mm and a single-layer exposure time of 4 s, test strips for tensile and bending elastomers are printed, and residual resin on the surface of the strips is cleaned.

[0048] Post-curing: The sample was placed in an oven at 110℃ for 4 hours with a humidity of >85% to complete the preparation.

[0049] Example 5: Preparation of a single-component, hygrothermal, multi-curing photosensitive resin: 2 parts of photoinitiator (TPO) were dissolved in 27 parts of ACMO, then 10 parts of NPGDA and 1 part of color paste were added, followed by 50 parts of PUA2 and stirring until homogeneous. At room temperature, 5.50 parts of curing agent aldehyde-imide (hydrolysis equivalent 240) were added and stirred for 1 hour until completely mixed. The UV resin was then prepared.

[0050] 3D printing: DLP oxygen permeation machine printing, parameters: exposure energy 5mW / cm² 2 With a layer thickness of 0.1 mm and a single-layer exposure time of 4 s, test strips for tensile and bending elastomers are printed, and residual resin on the surface of the strips is cleaned.

[0051] Post-curing: The sample was placed in an oven at 110℃ for 4 hours with a humidity of >85% to complete the preparation.

[0052] Example 6: Preparation of a single-component, hygrothermal, multi-curing photosensitive resin: 2 parts of photoinitiator (TPO) were dissolved in 27 parts of ACMO, then 10 parts of NPGDA and 1 part of color paste were added, followed by 50 parts of PUA2 and stirring until homogeneous. At room temperature, 7.33 parts of curing agent aldehyde-imide (hydrolysis equivalent 240) were added and stirred for 1 hour until completely mixed. The UV resin was then prepared.

[0053] 3D printing: DLP oxygen permeation machine printing, parameters: exposure energy 5mW / cm² 2 With a layer thickness of 0.1 mm and a single-layer exposure time of 4 s, test strips for tensile and bending elastomers are printed, and residual resin on the surface of the strips is cleaned.

[0054] Post-curing: The sample was placed in an oven at 110℃ for 4 hours with a humidity of >85% to complete the preparation.

[0055] Comparative Example 1: Preparation of a single-component, hygrothermal, multi-curing photosensitive resin: 2 parts of photoinitiator (TPO) were dissolved in 20 parts of EOEOEA, then 10 parts of DPGDA and 1 part of colorant were added, followed by 60 parts of PUA1 and stirring until homogeneous. At room temperature, 7 parts of curing agent (3,3'-diethyl-4,4'-diaminodiphenylmethane) were added and stirred for 1 hour until completely mixed. The UV resin was then prepared.

[0056] 3D printing: DLP oxygen permeation machine printing, parameters: exposure energy 5mW / cm² 2With a layer thickness of 0.1 mm and a single-layer exposure time of 4 s, tensile test specimens for elastomers and tear resistance test specimens were printed, and residual resin on the specimen surface was cleaned.

[0057] Post-curing: The sample was placed in an oven at 110℃ for 4 hours to complete the preparation.

[0058] Comparative Example 2: Preparation of a single-component, hygrothermal, multi-curing photosensitive resin: 2 parts of photoinitiator (TPO) were dissolved in 27 parts of ACMO, then 10 parts of NPGDA and 1 part of color paste were added, followed by 50 parts of PUA2 and stirring until homogeneous. At room temperature, 10 parts of curing agent polyetheramine T403 were added and stirred for 1 hour until completely mixed. The UV resin was then prepared.

[0059] 3D printing: DLP oxygen permeation machine printing, parameters: exposure energy 5mW / cm² 2 With a layer thickness of 0.1 mm and a single-layer exposure time of 4 s, test strips for tensile and bending elastomers are printed, and residual resin on the surface of the strips is cleaned.

[0060] Post-curing: The sample was placed in an oven at 110℃ for 4 hours to complete the preparation.

[0061] Comparative Example 3: Unlike Example 4, no post-curing was performed.

[0062] The above embodiments and comparative examples were tested, and the test results are as follows: Table 1: Elastomers

[0063] Table 2: Rigid Plastics

[0064] The resins of Examples 2 and 5 showed only a 5% viscosity change after being left at room temperature for 7 days, ensuring a continuous printing window of more than a week, which is completely unattainable by Comparative Examples 1 and 2 (direct amine addition, gelling within 24 hours). Moreover, after curing with humid heat, the tensile strength (20.5 MPa vs 18.5 MPa) of Example 2 and the tensile strength (45.6 MPa vs 42.3 MPa), elongation at break, and tear strength of Example 5 were all comparable to the comparative examples, demonstrating performance comparable to UV + thermosetting two-component resins.

[0065] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A single-component, moisture-curing, multi-stage photosensitive resin, characterized in that, The product comprises the following components in parts by weight: 40-70 parts of hindered urea polyurethane acrylate, 10-30 parts of multifunctional acrylate component, 10-40 parts of monomer diluent, 1-5 parts of photoinitiator, 0.5-3 parts of colorant, and 3-15 parts of latent curing agent; the mass ratio of the hindered urea polyurethane acrylate to the latent curing agent is 6.5:1 to 15:

1.

2. The single-component, moisture-curing, multi-stage photosensitive resin according to claim 1, characterized in that: The hindered urea polyurethane acrylate has any of the following structures: TBAEMA-HMDI-PTMG2000-HMDI-TBAEMA; TBAEMA-IPDI-PTMG1000-IPDI-TBAEMA; Among them, TBAEMA is ethyl 2-(tert-butylamino)methacrylate, HMDI is 4,4'-dicyclohexylmethane diisocyanate, IPDI is isophorone diisocyanate, and PTMG2000 and PTMG1000 are polytetrahydrofuran diols with number average molecular weights of 2000 and 1000, respectively.

3. The single-component, moisture-curing, multi-stage photosensitive resin according to claim 2, characterized in that: The hindered urea polyurethane acrylate is prepared by the following method: PTMG and diisocyanate were stirred and reacted at 20–40 °C for 0.5–2 h, then 500–2000 ppm of organometallic catalyst was added, and the temperature was raised to 60–80 °C for 1–3 h until the NCO content was below 5.5%. After cooling, TBAEMA is added dropwise. After the addition is complete, the mixture is kept at 70-80℃ for 1-3 hours until the NCO reaction endpoint is reached, thus obtaining the hindered urea polyurethane acrylate.

4. The single-component, moisture-curing, multi-stage photosensitive resin according to claim 3, characterized in that: The PTMG includes PTMG2000 or PTMG1000, the diisocyanate includes HMDI or IPDI, and the organometallic catalyst includes at least one of dibutyltin dilaurate, stannous octoate, di(dodecyl sulfide)dibutyltin, and dibutyltin diacetate.

5. The single-component, moisture-curing, multi-stage photosensitive resin according to claim 1, characterized in that: The multifunctional acrylate component includes at least one of trifunctional to hexafunctional polyurethane acrylate, polyester acrylate and epoxy acrylate.

6. The single-component, moisture-curing, multi-stage photosensitive resin according to claim 1, characterized in that: The monomer diluent includes at least one of isobornyl acrylate, acrylmorpholine, 2-phenoxyethyl acrylate, ethoxyethoxyethyl acrylate, tetrahydrofurfuryl acrylate, and laurate.

7. The single-component, moisture-curing, multi-stage photosensitive resin according to claim 1, characterized in that: The photoinitiator includes at least one of acylphosphine oxide photoinitiators, α-hydroxy ketone photoinitiators, α-amino ketone photoinitiators, benzoyl ether photoinitiators, benzophenone photoinitiators, thioxanthone photoinitiators, and anthraquinone photoinitiators.

8. The single-component, moisture-curing, multi-stage photosensitive resin according to claim 1, characterized in that: The latent curing agent includes at least one of aldimine, ketimine, and oxazolidine.

9. A method for preparing a single-component, moisture-curing, multi-stage photosensitive resin, characterized in that: The application of the single-component, hygrothermal, multi-curing photosensitive resin according to any one of claims 1 to 8 includes the following steps: By weight, hindered urea polyurethane acrylate, multifunctional acrylate component, monomer diluent, photoinitiator, colorant and latent curing agent are mixed evenly to obtain the single-component hygrothermal multi-curing photosensitive resin.

10. The application of the single-component, hydrothermal multi-curing photosensitive resin according to any one of claims 1 to 8 in photocuring 3D printing, characterized in that, The single-component, hygrothermal multi-curing photosensitive resin is subjected to photocuring 3D printing to obtain a photocured molded part. The photocured molded part is then subjected to hygrothermal post-curing. The hygrothermal post-curing temperature is 100-120℃, the relative humidity is ≥85%, and the time is 2-6 hours.

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