Preparation method of light-cured resin for 3D printing

Abstract

The invention relates to a preparation method of light-cured resin for 3D printing. The preparation method comprises the following steps: obtaining a monodisperse nano low-carbon composite filler; pre-polymerizing the monodisperse nano low-carbon composite filler, a photosensitive monomer and a photoinitiator to target viscosity to obtain a first prepolymer; adding a cross-linking agent into the first prepolymer to obtain a second prepolymer; mixing and stirring the second prepolymer, a reactive diluent, a nano filler and a pigment dispersant to obtain a prepolymer mixed system; and sequentially defoaming and adjusting the viscosity of the prepolymer mixed system, and adding a lubricant into the prepolymer mixed system after the viscosity is adjusted to obtain the light-cured resin. Through preparation of the monodisperse nano low-carbon composite filler and a surface modification process, low viscosity and rapid curing performance of the high-solid-content light-cured resin are achieved, and the requirement for efficient and precise forming of 3D printing is met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of composite materials, and particularly relates to a preparation method of a photocuring resin for 3D printing. BACKGROUND

[0002] The photocuring (SLA) 3D printing technology firstly adds a photoinitiator into a liquid photosensitive resin to form a uniform mixture, and then is placed into a 3D printer; a target three-dimensional entity model is processed in layers, and a specific wavelength ultraviolet light is used to scan the resin layer by layer, so that the irradiation area is selectively cured to form, and the non-scanning area remains liquid; after layer-by-layer accumulation and curing, the final product is formed, which has the advantages of high production efficiency, energy saving and environmental protection, etc.

[0003] However, the resin system relied on by the technology has long used epoxy acrylate, polyurethane acrylate, polyester acrylate and silicone polymer as a base material, and has inherent defects such as high viscosity, slow curing or high cost. In order to reduce the cost of raw materials and reduce resource consumption, the existing technology introduces a low-carbon composite filler derived from steel slag solid waste, forms a porous structure material through superfine vertical grinding and surface modification, and significantly reduces the production cost. However, under high filler content, the problems of deteriorated rheological property and low curing efficiency cannot be solved. Therefore, synergistically reducing the viscosity of the resin and shortening the exposure time have become a technical problem to be solved to break through the printing speed bottleneck of high filler resin. SUMMARY

[0004] The present application provides a preparation method of a photocuring resin for 3D printing to solve the technical problem of how to improve the flow efficiency of the photocuring resin and accelerate the curing response. The present application provides a preparation method of a photocuring resin for 3D printing, comprising: obtaining monodisperse nanometer low-carbon composite fillers; prepolymerizing the monodisperse nanometer low-carbon composite fillers, a photosensitive monomer and a photoinitiator to a target viscosity to obtain a first prepolymer; adding a crosslinking agent to the first prepolymer to obtain a second prepolymer; mixing and stirring the second prepolymer, an active diluent, a nanofiller and a pigment dispersant to obtain a prepolymer mixture system; performing defoaming and adjusting the viscosity of the prepolymer mixture system in sequence, and adding a lubricant to the prepolymer mixture system after adjusting the viscosity to obtain a photocuring resin.

[0005] Optionally, the monodisperse nanometer low-carbon composite fillers comprise lysine, deionized water and low-carbon composite fillers.

[0006] Optionally, the particle size of the low-carbon composite fillers is greater than or equal to 800 mesh.

[0007] Optionally, the low-carbon composite filler is insoluble in water and organic solvents.

[0008] Optionally, the stirring is carried out under nitrogen protection.

[0009] Optionally, the target viscosity is 5000cps-7000cps, and the reaction temperature of the prepolymerization is 60℃-70℃.

[0010] Optionally, the nanofiller comprises monodisperse nanometer low-carbon material and modified titanium dioxide, and the modified titanium dioxide is obtained by surface modification with a silane coupling agent.

[0011] Optionally, the defoaming is carried out by vacuum defoaming, the vacuum degree of the vacuum defoaming is-0.1MPa--0.05MPa, and the time of the vacuum defoaming is 10min-30min.

[0012] Optionally, the lubricant comprises at least one of the following: silicone leveling agent, fluorine surfactant, and metal soap compound coated with inorganic nanometer layer.

[0013] Optionally, the viscosity of the photocuring resin is 20cps-35cps, the single-layer exposure time of the photocuring resin is ≤1.0s, and the critical exposure amount of the photocuring resin is ≤4.15mJ / cm 2 .

[0014] Compared with the prior art, the above technical solution provided by the embodiments of the present application has the following advantages: This application provides a method for preparing a photocurable resin for 3D printing. By designing a micro-nano porous structure and surface photosensitive functionalization of steel slag filler, low viscosity and ultra-fast curing of the resin are synergistically achieved at high solids content, overcoming the technical problem of "high viscosity-slow curing" in traditional photocurable materials. First, a monodisperse nano-low-carbon composite filler is obtained. The monodisperse nano-low-carbon composite filler, photosensitive monomer, and photoinitiator are prepolymerized to a target viscosity to obtain a first prepolymer. A crosslinking agent is added to the first prepolymer to obtain a second prepolymer. This process constructs a controllable crosslinked network framework through prepolymerization, locking in the uniform distribution of the monodisperse filler while regulating rheological behavior, enabling the resin to reach the target viscosity before curing, providing a structural basis for high-precision and rapid printing. Subsequently, the second prepolymer, reactive diluent, nanofiller, and pigment dispersant are mixed and stirred to obtain a prepolymer mixture system. This process synergistically regulates the system viscosity and curing shrinkage rate through the reactive diluent, while simultaneously enhancing the dispersion stability of the nanofiller and the uniformity of pigment color development, achieving precise construction of a high-solids-content, low-viscosity prepolymer mixture system under nitrogen protection. Finally, the prepolymer mixture is defoamed and its viscosity adjusted sequentially, and a lubricant is added to the prepolymer mixture after viscosity adjustment to obtain a photocurable resin. This process eliminates microbubbles through vacuum defoaming, precisely controls rheological behavior through viscosity adjustment, and introduces a light-transmitting lubricant to optimize interfacial slip, simultaneously ensuring smooth resin printing, uniform curing, and surface precision of the finished product. Attached Figure Description

[0015] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a flowchart illustrating a method for preparing a photocurable resin for 3D printing, as provided in an embodiment of this application. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0019] The range descriptions used herein, such as numerical ranges and proportional ranges, include all possible sub-ranges and single numerical values ​​within that range. For example, the range descriptions of "1 to 6" or "1~6" cover all sub-ranges (such as 1 to 3, 2 to 5, etc.) and single numbers (such as 1, 2, 3, 4, 5, 6) between 1 and 6. Unless otherwise specified, the terms "including" and "contains" as used herein mean "including but not limited to"; relational terms such as "first" and "second" are used only to distinguish different entities or operations and do not imply an actual order or relationship; "and / or" indicates that multiple situations can exist individually or simultaneously; expressions such as "at least one," "multiple," and "at least one" refer to any combination of the corresponding objects, including combinations of single or multiple objects. The proportional relationships mentioned herein, such as mass ratios and molar ratios, should be understood as the correspondence between the first and second terms of a proportional formula, according to the order of description. The raw materials, reagents, instruments, and equipment used herein can all be obtained through commercial purchase or prepared using existing methods.

[0020] Figure 1 This is a flowchart illustrating a method for preparing a photocurable resin for 3D printing, as provided in an embodiment of this application.

[0021] Please see Figure 1 This application provides a method for preparing a photocurable resin for 3D printing, comprising: S1. Obtain monodisperse nano-low-carbon composite filler; S2. Prepolymerize the monodisperse nano-low-carbon composite filler, photosensitive monomer and photoinitiator to the target viscosity to obtain the first prepolymer; S3. Add a crosslinking agent to the first prepolymer to obtain a second prepolymer; S4. Mix and stir the second prepolymer, reactive diluent, nanofiller and pigment dispersant to obtain a prepolymer mixture system; S5. The prepolymer mixture is defoamed and its viscosity is adjusted sequentially, and a lubricant is added to the prepolymer mixture after the viscosity is adjusted to obtain a photocurable resin.

[0022] Low-carbon composite filler: Porous inorganic microparticles formed from steel slag through ultrafine vertical milling and surface modification. Monodisperse nano-low-carbon composite material: A nanoscale dispersion formed by modifying low-carbon composite filler with lysine aqueous phase interface. Stable monodispersion and interfacial compatibilization of the filler in the resin are achieved through double-layer repulsion and organic chain segment grafting. Photosensitive monomer: A low-molecular-weight compound containing photocurable active groups. Under UV initiation, it participates in polymerization reactions to form the resin network framework and provides viscosity control. Photoinitiator: A photosensitive compound that generates free radicals or cations under specific wavelength UV excitation. It initiates the polymerization reaction of photosensitive monomers and prepolymers to achieve rapid resin curing. Crosslinking agent: A multifunctional compound containing ≥2 photocurable active groups. It introduces three-dimensional crosslinking points into the prepolymer system to improve the resin's mechanical strength and control curing shrinkage. Reactive diluent: A low-viscosity monomer containing a single photocurable group. It reduces the viscosity of the resin system and participates in the construction of the crosslinking network, simultaneously optimizing leveling and controlling shrinkage. Pigment dispersant: This is a pre-mixed mixture of pigment and dispersant. The dispersant molecules directionally coat the pigment particles, breaking down surface energy barriers to achieve a stable nanoscale dispersion. This eliminates uneven color development and rheological runaway caused by agglomeration, ensuring color consistency and smooth printing of high-solids resins. Lubricant: By reducing the separation resistance between the resin and the molding interface and inhibiting interlayer adhesion, this synergistically optimizes print release smoothness and cured part surface finish, while maintaining the system's UV transmittance to ensure curing efficiency.

[0023] In the above technical solution, the low-carbon composite filler is monodispersed by lysine aqueous phase modification, breaking the agglomeration energy barrier; the modified filler is prepolymerized with photosensitive monomer and photoinitiator to the target viscosity to construct a cross-linked network skeleton to lock the filler distribution and suppress sedimentation and stratification; then a cross-linking agent is added to strengthen the network, and then it is mixed with reactive diluent, nanofiller and pigment dispersant under nitrogen protection. The viscosity stability of the high solid content system is maintained by the viscosity reduction of the diluent through pore penetration and the anchoring synergy of the dispersant; finally, microbubbles are eliminated by vacuum degassing, and a light-transmitting lubricant is added to optimize the interfacial slip, so as to achieve ultra-low viscosity flow and high-speed light response simultaneously.

[0024] In some embodiments, the monodisperse nano-low-carbon composite filler includes: lysine, deionized water, and low-carbon composite filler.

[0025] By using lysine in an aqueous phase to modify the interface of low-carbon composite fillers and deagglomerate them, monodisperse nanoscale dispersions are formed.

[0026] In some embodiments, the particle size of the low-carbon composite filler is ≥800 mesh.

[0027] Particle size: refers to the size distribution range of filler particles, determined by standard sieving methods, and characterizes the physical dispersion scale of the filler in the resin system. Low-carbon composite fillers with a particle size ≥800 mesh ensure that the filler possesses a fully developed porous structure and a suitable surface-to-volume ratio. While maintaining resin flowability, this provides efficient penetration channels for photosensitive components, synergistically achieving uniform photocuring in high-solids-content systems. For example, the particle size of low-carbon composite fillers can be 800 mesh, 810 mesh, 820 mesh, 830 mesh, 840 mesh, 850 mesh, 860 mesh, etc.

[0028] In some embodiments, the low-carbon composite filler is insoluble in water and organic solvents.

[0029] Low-carbon composite fillers are insoluble in water and organic solvents. This is to maintain the physical structural integrity and porous characteristics of the filler in the resin system, and to avoid pore collapse, interfacial compatibility deterioration and rheological property loss caused by dissolution or swelling, thereby ensuring the storage stability and printing reliability of high solids content resins.

[0030] In some embodiments, the stirring is carried out under nitrogen protection.

[0031] The prepolymer is stirred under nitrogen protection to isolate oxygen and suppress the oxygen inhibition effect in free radical polymerization, ensuring that the prepolymer maintains stable reactivity during stirring, and guaranteeing the uniformity of deep crosslinking and final mechanical properties of the photocurable resin.

[0032] In some embodiments, the target viscosity is 5000 cps to 7000 cps, and the reaction temperature of the prepolymer is 60°C to 70°C.

[0033] The target viscosity is between 5000 cps and 7000 cps. This aims to balance the structural stability and processing flowability of the prepolymer, ensuring uniform filler dispersion while resisting sedimentation and stratification, and providing a controllable rheological window for subsequent dilution processes. Ultimately, this guarantees the printing accuracy and curing consistency of the high-solids-content resin. For example, the target viscosity can be 5000 cps, 5500 cps, 6000 cps, 6500 cps, or 7000 cps. The prepolymer reaction temperature is between 60℃ and 70℃. This aims to optimize the prepolymer network structure while ensuring a controllable reaction rate, avoiding the risk of gelation caused by localized overheating. Simultaneously, it activates active sites on the filler surface to enhance interfacial bonding, providing a homogeneous and stable pre-crosslinked foundation for the high-solids-content resin. For example, the prepolymer reaction temperature can be 60℃, 62℃, 64℃, 66℃, 68℃, or 70℃.

[0034] In some embodiments, the nanofiller comprises monodisperse low-carbon nanomaterials and modified titanium dioxide, wherein the modified titanium dioxide is obtained by surface modification with a silane coupling agent.

[0035] The nanofillers include monodisperse low-carbon nanomaterials and modified titanium dioxide. Through the synergistic effect of enhanced interfacial bonding and photomodulation, they improve interlayer bonding strength and UV response efficiency while maintaining the low viscosity of the resin, achieving a dual breakthrough in mechanical properties and curing precision in high-solids content systems. The modified titanium dioxide is obtained by surface modification with a silane coupling agent, which aims to break the surface energy barrier of nanoparticles to achieve stable monodispersion in the resin system. At the same time, the UV scattering behavior is directionally regulated by chemically grafting photosensitive groups, synergistically ensuring the deep curing uniformity and interfacial bonding reliability of high-solids content resins.

[0036] In some embodiments, the degassing is performed using vacuum degassing, wherein the vacuum degree of the vacuum degassing is -0.1MPa to -0.05MPa, and the vacuum degassing time is 10min to 30min.

[0037] Vacuum degassing is employed, using a negative pressure environment to physically release microbubbles from within the resin. This eliminates light scattering defects and weak interfacial areas during curing, ensuring uniform UV penetration in the high-solids-content system and the structural integrity of the final product. The vacuum level during degassing is between -0.1 MPa and -0.05 MPa to establish a balance between efficiently removing microbubbles and maintaining resin component stability. Precise negative pressure control enables the directional migration and escape of bubbles, while simultaneously preventing the prepolymer's rheological properties from becoming uncontrollable due to the vaporization of low-boiling-point components. For example, the vacuum level during degassing can be -0.1 MPa, -0.09 MPa, -0.08 MPa, -0.07 MPa, -0.06 MPa, or -0.05 MPa. The degassing time is between 10 and 30 minutes to ensure the directional migration and escape of bubbles while avoiding over-treatment that could lead to the volatilization of active components or uncontrolled prepolymerization. For example, the vacuum degassing time can be 10 min, 15 min, 20 min, 25 min, 30 min, etc.

[0038] In some embodiments, the lubricant includes at least one of the following: silicone leveling agents, fluorinated surfactants, and metal soap compounds with an inorganic nanolayer coated on the surface.

[0039] The lubricant contains organosilicon leveling agents, fluorinated surfactants, and metal soap compounds with inorganic nanolayers coated on the surface. Through multiple mechanisms, it synergistically regulates the interfacial tension and slip properties of the resin, suppressing interlayer adhesion and leveling defects while ensuring light transmittance, thus achieving high-precision printing surface quality in a high-solids content system.

[0040] In some embodiments, the viscosity of the photocurable resin is 20 cps to 35 cps, the single-layer exposure time of the photocurable resin is ≤1 s, and the critical exposure dose of the photocurable resin is ≤4.15 mJ / cm².2 .

[0041] The viscosity of the photocurable resin is between 20 cps and 35 cps to achieve spontaneous wetting of microchannels and submicron-level feature reproduction in ultra-high precision printing scenarios. Its extremely low viscosity eliminates leveling shear stress, ensuring the molding fidelity and optical-grade surface quality of micro / nano structure devices. For example, the viscosity of the photocurable resin can be 20 cps, 25 cps, 30 cps, 35 cps, etc. The single-layer exposure time of the photocurable resin is the duration of light irradiation required for a single layer of resin to reach the critical curing conversion rate. A single-layer exposure time of ≤1.0 s is used to overcome the photocuring kinetics bottleneck of high-solids-content resins. This achieves the second-level molding speed required for industrial-grade mass production through a qualitative improvement in UV response efficiency, while simultaneously eliminating thermal accumulation deformation caused by long-term irradiation, ensuring printing accuracy and production economy. For example, the single-layer exposure time of the photocurable resin can be 0.2 s, 0.4 s, 0.6 s, 0.8 s, 1.0 s, etc. Critical exposure threshold of a photocurable resin: the minimum light energy threshold per unit area required to initiate a photocuring reaction in the resin system. The critical exposure threshold of a photocurable resin is ≤4.15 mJ / cm². 2 This is to achieve a qualitative leap in the photocuring kinetics of high-solids-content resin systems, breaking through the speed limits of industrial mass production through hypersensitive photoresponse while ensuring deep penetration capability, thus providing an energetic basis for the ultra-fast, high-precision printing of complex and precise components. For example, the critical exposure dose of the photocurable resin can be 4.10 mJ / cm². 2 4.12 mJ / cm 2 4.13 mJ / cm 2 4.14 mJ / cm 2 4.15 mJ / cm 2 wait.

[0042] The present application is further illustrated below with reference to specific embodiments. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to national / industry standards; if there is no corresponding national / industry standard, they are performed according to general international standards, conventional conditions, or conditions recommended by the manufacturer.

[0043] Example 1 Add 2g of lysine to a single-necked flask, then add deionized water and stir at 1000rpm for 12min in an oil bath at 60℃. Then add 20g of low-carbon composite filler to the single-necked flask and stir at 60℃ for 12h until the solution is clear to obtain monodisperse nano low-carbon composite filler.

[0044] The monodisperse nano-low carbon composite filler, photosensitive monomer and photoinitiator were prepolymerized at 60°C to a target viscosity of 5000 cps to obtain the first polymer.

[0045] A crosslinking agent was added to the first prepolymer and reacted at 90°C for 8 hours to obtain the second prepolymer.

[0046] The second prepolymer, reactive diluent, and nanofiller were stirred at 300 rpm in an oil bath at 50°C under nitrogen protection, and then a pre-mixed pigment dispersant was added to obtain a prepolymer mixture system; wherein, the nanofiller was titanium dioxide surface modified with silane coupling agent.

[0047] The prepolymer mixture was degassed under vacuum at -0.1 MPa for 30 min, the viscosity was adjusted to 9000 cps, and 0.1 parts of zinc stearate were added to obtain the photocurable resin.

[0048] Example 2 Add 2g of lysine to a single-necked flask, then add deionized water and stir at 1000rpm for 12min in an oil bath at 60℃. Then add 25g of low-carbon composite filler to the single-necked flask and stir at 60℃ for 12h until the solution is clear to obtain monodisperse nano low-carbon composite filler.

[0049] The monodisperse nano-low carbon composite filler, photosensitive monomer and photoinitiator were prepolymerized at 65°C to a target viscosity of 6000 cps to obtain the first polymer.

[0050] A crosslinking agent was added to the first prepolymer and reacted at 85°C for 9 hours to obtain the second prepolymer.

[0051] The second prepolymer, reactive diluent, and nanofiller were stirred at 350 rpm in an oil bath at 50°C under nitrogen protection, and then a pre-mixed pigment dispersant was added to obtain a prepolymer mixture system; wherein, the nanofiller was titanium dioxide surface modified with silane coupling agent.

[0052] The prepolymer mixture was degassed under vacuum at -0.1 MPa for 30 min, the viscosity was adjusted to 9000 cps, and 0.2 parts of zinc stearate were added to obtain the photocurable resin.

[0053] Example 3 Add 2g of lysine to a single-necked flask, then add deionized water and stir at 1000rpm for 12min in an oil bath at 60℃. Then add 30g of low-carbon composite filler to the single-necked flask and stir at 60℃ for 12h until the solution is clear to obtain monodisperse nano low-carbon composite filler.

[0054] The monodisperse nano-low carbon composite filler, photosensitive monomer and photoinitiator were prepolymerized at 70°C to a target viscosity of 7000 cps to obtain the first polymer.

[0055] A crosslinking agent was added to the first prepolymer and reacted at 85°C for 9 hours to obtain the second prepolymer.

[0056] The second prepolymer, reactive diluent, and nanofiller were stirred at 350 rpm in an oil bath at 50°C under nitrogen protection, and then a pre-mixed pigment dispersant was added to obtain a prepolymer mixture system; wherein, the nanofiller was titanium dioxide surface modified with silane coupling agent.

[0057] The prepolymer mixture was degassed under vacuum at -0.1 MPa for 30 min, the viscosity was adjusted to 9000 cps, and 0.3 parts of zinc stearate were added to obtain the photocurable resin.

[0058] Example 4 Add 2g of lysine to a single-necked flask, then add deionized water and stir at 1000rpm for 12min in an oil bath at 60℃. Then add 35g of low-carbon composite filler to the single-necked flask and stir at 60℃ for 12h until the solution is clear to obtain monodisperse nano low-carbon composite filler.

[0059] The monodisperse nano-low carbon composite filler, photosensitive monomer and photoinitiator were prepolymerized at 70°C to a target viscosity of 7000 cps to obtain the first polymer.

[0060] A crosslinking agent was added to the first prepolymer and reacted at 90°C for 9 hours to obtain the second prepolymer.

[0061] The second prepolymer, reactive diluent, and nanofiller were stirred at 350 rpm in an oil bath at 50°C under nitrogen protection, and then a pre-mixed pigment dispersant was added to obtain a prepolymer mixture system; wherein, the nanofiller was titanium dioxide surface modified with silane coupling agent.

[0062] The prepolymer mixture was degassed under vacuum at -0.1 MPa for 30 min, the viscosity was adjusted to 9000 cps, and 0.4 parts of zinc stearate were added to obtain the photocurable resin.

[0063] Example 5 Add 2g of lysine to a single-necked flask, then add deionized water and stir at 1000rpm for 12min in an oil bath at 60℃. Then add 40g of low-carbon composite filler to the single-necked flask and stir at 60℃ for 12h until the solution is clear to obtain monodisperse nano low-carbon composite filler.

[0064] The monodisperse nano-low carbon composite filler, photosensitive monomer and photoinitiator were prepolymerized at 70°C to a target viscosity of 7000 cps to obtain the first polymer.

[0065] A crosslinking agent was added to the first prepolymer and reacted at 95°C for 9 hours to obtain the second prepolymer.

[0066] The second prepolymer, reactive diluent, and nanofiller were stirred at 350 rpm in an oil bath at 50°C under nitrogen protection, and then a pre-mixed pigment dispersant was added to obtain a prepolymer mixture system; wherein, the nanofiller was titanium dioxide surface modified with silane coupling agent.

[0067] The prepolymer mixture was degassed under vacuum at -0.1 MPa for 30 min, the viscosity was adjusted to 9000 cps, and 0.5 parts of zinc stearate were added to obtain the photocurable resin.

[0068] Comparative Example 1 Add 3g of lysine to a single-necked flask, then add deionized water and stir at 1000rpm for 20min in an oil bath at 60℃. Then add 20g of low-carbon composite filler to the single-necked flask and stir at 80℃ for 12h until the solution is clear to obtain monodisperse nano low-carbon composite filler.

[0069] The monodisperse nano-low carbon composite filler, photosensitive monomer and photoinitiator were prepolymerized at 60°C to a target viscosity of 5000 cps to obtain the first polymer.

[0070] A crosslinking agent was added to the first prepolymer and reacted at 90°C for 8 hours to obtain the second prepolymer.

[0071] The second prepolymer, reactive diluent, and nanofiller were stirred at 300 rpm in an oil bath at 50°C under nitrogen protection, and then a pre-mixed pigment dispersant was added to obtain a prepolymer mixture system; wherein, the nanofiller was titanium dioxide surface modified with silane coupling agent.

[0072] The prepolymer mixture was degassed under vacuum at -0.1 MPa for 30 min, the viscosity was adjusted to 9000 cps, and 0.1 parts of zinc stearate were added to obtain the photocurable resin.

[0073] Comparative Example 2 Add 4g of lysine to a single-necked flask, then add deionized water and stir at 1000rpm for 20min in an oil bath at 60℃. Then add 25g of low-carbon composite filler to the single-necked flask and stir at 80℃ for 12h until the solution is clear to obtain monodisperse nano low-carbon composite filler.

[0074] The monodisperse nano-low carbon composite filler, photosensitive monomer and photoinitiator were prepolymerized at 65°C to a target viscosity of 6000 cps to obtain the first polymer.

[0075] A crosslinking agent was added to the first prepolymer and reacted at 85°C for 9 hours to obtain the second prepolymer.

[0076] The second prepolymer, reactive diluent, and nanofiller were stirred at 350 rpm in an oil bath at 50°C under nitrogen protection, and then a pre-mixed pigment dispersant was added to obtain a prepolymer mixture system; wherein, the nanofiller was titanium dioxide surface modified with silane coupling agent.

[0077] The prepolymer mixture was degassed under vacuum at -0.1 MPa for 30 min, the viscosity was adjusted to 9000 cps, and 0.2 parts of zinc stearate were added to obtain the photocurable resin.

[0078] Comparative Example 3 Add 5g of lysine to a single-necked flask, then add deionized water and stir at 1000rpm for 20min in an oil bath at 60℃. Then add 30g of low-carbon composite filler to the single-necked flask and stir at 80℃ for 12h until the solution is clear to obtain monodisperse nano low-carbon composite filler.

[0079] The monodisperse nano-low carbon composite filler, photosensitive monomer and photoinitiator were prepolymerized at 70°C to a target viscosity of 7000 cps to obtain the first polymer.

[0080] A crosslinking agent was added to the first prepolymer and reacted at 85°C for 9 hours to obtain the second prepolymer.

[0081] The second prepolymer, reactive diluent, and nanofiller were stirred at 350 rpm in an oil bath at 50°C under nitrogen protection, and then a pre-mixed pigment dispersant was added to obtain a prepolymer mixture system; wherein, the nanofiller was titanium dioxide surface modified with silane coupling agent.

[0082] The prepolymer mixture was degassed under vacuum at -0.1 MPa for 30 min, the viscosity was adjusted to 9000 cps, and 0.3 parts of zinc stearate were added to obtain the photocurable resin.

[0083] Comparative Example 4 Add 6g of lysine to a single-necked flask, then add deionized water and stir at 1000rpm for 25min in an oil bath at 60℃. Then add 35g of low-carbon composite filler to the single-necked flask and stir at 80℃ for 12h until the solution is clear to obtain monodisperse nano low-carbon composite filler.

[0084] The monodisperse nano-low carbon composite filler was prepolymerized with a photosensitive monomer and a photoinitiator at 70°C to a target viscosity of 7000 cps to obtain the first polymer.

[0085] A crosslinking agent was added to the first prepolymer and reacted at 90°C for 9 hours to obtain the second prepolymer.

[0086] The second prepolymer, reactive diluent, and nanofiller were stirred at 350 rpm in an oil bath at 50°C under nitrogen protection, and then a pre-mixed pigment dispersant was added to obtain a prepolymer mixture system; wherein, the nanofiller was titanium dioxide surface modified with silane coupling agent.

[0087] The prepolymer mixture was degassed under vacuum at -0.1 MPa for 30 min, the viscosity was adjusted to 9000 cps, and 0.4 parts of zinc stearate were added to obtain the photocurable resin.

[0088] Comparative Example 5 Add 7g of lysine to a single-necked flask, then add deionized water and stir at 1000rpm for 20min in an oil bath at 60℃. Then add 40g of low-carbon composite filler to the single-necked flask and stir at 80℃ for 12h until the solution is clear to obtain monodisperse nano low-carbon composite filler.

[0089] The monodisperse nano-low carbon composite filler was prepolymerized with a photosensitive monomer and a photoinitiator at 70°C to a target viscosity of 7000 cps to obtain the first polymer.

[0090] A crosslinking agent was added to the first prepolymer and reacted at 95°C for 9 hours to obtain the second prepolymer.

[0091] The second prepolymer, reactive diluent, and nanofiller were stirred at 350 rpm in an oil bath at 50°C under nitrogen protection, and then a pre-mixed pigment dispersant was added to obtain a prepolymer mixture system; wherein, the nanofiller was titanium dioxide surface modified with silane coupling agent.

[0092] The prepolymer mixture was degassed under vacuum at -0.1 MPa for 30 min, the viscosity was adjusted to 9000 cps, and 0.5 parts of zinc stearate were added to obtain the photocurable resin.

[0093] Effect data: The effect data of Examples 1 to 5 and Comparative Examples 1 to 5 are shown in Table 1.

[0094] Experimental methods for obtaining effect data: Double bond content determination: Fourier transform infrared spectroscopy was used. The resin sample was coated onto a wafer (e.g., KBr) and placed in an infrared spectrometer, simultaneously irradiated with UV light of a specific wavelength, and the spectrum was continuously acquired. Double bond conversion rate determination: Fourier transform infrared spectroscopy was used. Viscosity determination: A rotational rheometer was used. Critical exposure determination: The Working Curve method was used. This method measures the cured thickness at a series of different exposure energies and then fits the result using a mathematical model. Curing depth determination: The Working Curve method was used. This method measures the cured thickness at a series of different exposure energies and then fits the result using a mathematical model. Table 1

[0095] The above effect data table provides a clear comparison of the differences between various embodiments and comparative examples. The following conclusions can be drawn: As shown in Examples 1-5 and Comparative Examples 1-5, the critical exposure amount gradually decreases with the increase of low-carbon composite filler. The lower the critical exposure amount, the shorter the exposure time required to reach critical curing under a fixed light source irradiance, and the more layers can be formed per unit time, thus resulting in a faster printing speed.

[0096] As shown in Examples 1-5 and Comparative Example 5, the double bond content gradually decreases with the increase of low-carbon composite filler. However, due to the additional reactive sites provided by surface photosensitive modification and the oxygen-blocking effect of the dense interface layer, the double bond conversion rate gradually increases to 60%, significantly higher than the conversion rate (58%) of Comparative Example 5 with the same double bond content. This indicates that the present invention achieves ultra-low viscosity flow of high-filler resin (20cps~35cps) and ≤4.15mJ / cm³ simultaneously through surface photosensitive modification and a porous viscosity-reducing structure. 2 High-speed photoresponse overcomes the contradiction between flow efficiency A and curing speed.

[0097] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed in this application.

Claims

1. A method for the preparation of a photocured resin for 3D printing, characterized in that, The application relates to a method for preparing a light-cured resin. The method comprises the following steps: a monodisperse nanometer low-carbon composite filler is obtained; the monodisperse nanometer low-carbon composite filler, a photosensitive monomer and a photoinitiator are pre-polymerized to a target viscosity to obtain a first pre-polymer; a crosslinking agent is added into the first pre-polymer to obtain a second pre-polymer; the second pre-polymer, an active diluent, a nanometer filler and a pigment dispersant are mixed and stirred to obtain a pre-polymer mixed system; 2. The method of claim 1, wherein the photopolymerizable resin is prepared by mixing the monomer, the photopolymerization initiator, the photopolymerization inhibitor, and the photopolymerization synergist. the pre-polymer mixed system is subjected to bubble removal and viscosity adjustment in sequence, and a lubricant is added into the pre-polymer mixed system after viscosity adjustment to obtain the light-cured resin.

3. The method of claim 1, wherein the photocurable resin is prepared by mixing the monomer, the photopolymerization initiator, and the photopolymerization inhibitor. The monodisperse nanometer low-carbon composite filler comprises lysine, deionized water and a low-carbon composite filler.

4. The method of claim 1, wherein the photocurable resin is prepared by mixing the monomer, the photopolymerization initiator, and the photopolymerization inhibitor. The particle size of the low-carbon composite filler is greater than or equal to 800 meshes.

5. The method of claim 1, wherein the photocurable resin is prepared by mixing the monomer, the photopolymerization initiator, and the photopolymerization inhibitor. The low-carbon composite filler is insoluble in water and organic solvents.

6. The method of claim 1, wherein the photocurable resin is prepared by mixing the monomer, the photopolymerization initiator, and the photopolymerization inhibitor. The stirring is carried out under nitrogen protection.

7. The method of claim 1, wherein the photocurable resin is prepared by mixing the monomer, the photopolymerization initiator, and the photopolymerization inhibitor. The target viscosity is 5000cps-7000cps, and the pre-polymerization reaction temperature is 60 DEG C-70 DEG C.

8. The method for preparing the photocurable resin according to claim 1, characterized in that, The nanometer filler comprises a monodisperse nanometer low-carbon material and modified titanium dioxide, and the modified titanium dioxide is obtained through surface modification by a silane coupling agent.

9. The method of claim 1, wherein the photocurable resin is prepared by mixing the monomer, the photopolymerization initiator, and the photopolymerization inhibitor. The vacuum degree of the vacuum bubble removal is-0.1MPa to-0.05MPa, and the vacuum bubble removal time is 10min-30min. The lubricant comprises at least one of the following: a silicone leveling agent, a fluorine surfactant and a metal soap compound coated with an inorganic nanometer layer.

10. The method for preparing the photocurable resin according to claim 1, characterized in that, The viscosity of the photocuring resin is 20cps-35cps, the single-layer exposure time of the photocuring resin is ≤1.0s, and the critical exposure amount of the photocuring resin is ≤4.15mJ / cm 2 .

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