Zirconia ceramic slurry, preparation method and application thereof, and 3D printed zirconia ceramic and application thereof

Abstract

The application provides a zirconia ceramic slurry, a preparation method and application thereof, and 3D printed zirconia ceramic and application thereof, and relates to the field of additive manufacturing technology.The composition of the zirconia ceramic slurry provided by the application comprises modified zirconia powder, resin premix liquid, additives, photoinitiator and thermal initiator; the modified zirconia powder is obtained by modifying yttria-doped zirconia powder with one or more modifiers selected from the group consisting of methacrylic acid, 3-(isobutenoyloxy)propyl trimethoxysilane and stearic acid; and the components of the resin premix liquid comprise acrylate oligomer and active diluent. The zirconia ceramic slurry provided by the application has high solid content and low viscosity, is suitable for various models of DLP printers of ultraviolet light and visible light, and the 3D printed zirconia ceramic obtained through 3D printing, photocuring, thermal curing, defatting and sintering has high density and excellent mechanical properties, and can meet the mechanical property standards of dental restoratives.

Description

Technical Field

[0001] This invention relates to the field of additive manufacturing technology, specifically to a zirconia ceramic slurry, its preparation method and application, and 3D printing of zirconia ceramics and its application. Background Technology

[0002] Zirconia ceramics possess structural properties such as high strength, high hardness, high temperature resistance, corrosion resistance, and high gloss. They also have a wide range of functionalities, including dielectric, piezoelectric, semiconductor, acousto-optic, superconducting, magnetic, and biocompatible properties. As a result, they are widely used in many defense and civilian fields such as aerospace, 5G communication, sensors, biomedicine, and jewelry.

[0003] Photopolymerization 3D printing technology is a new technological approach for the preparation, processing, and production of dental ceramic materials, offering advantages such as digitalization, intelligence, high precision, high efficiency, personalized customization, mass production, and ease of molding complex shapes. It only requires obtaining a medical image model of the teeth through oral scanning, CT, or CBCT scans, followed by 3D reconstruction, and then rapidly manufacturing personalized all-ceramic dental restorations such as crowns, inlays, high-mount inlays, veneers, and bridges using 3D printing technology. Currently, the flexural strength of all-ceramic crowns prepared using traditional methods can reach over 1200 MPa. The density of 3D-printed all-ceramic crowns is around 95%, and their flexural strength is mostly between 500 and 600 MPa, even less than half the strength of all-ceramic crowns prepared using traditional methods. The key issues restricting the industrialization of 3D-printed all-ceramic dental restorations are the low density and poor mechanical properties of the material after printing and sintering. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a zirconia ceramic slurry, its preparation method and application, and 3D printed zirconia ceramics and their applications. The zirconia ceramic slurry provided by this invention has a high solid content and low viscosity, and exhibits high double bond conversion efficiency after photocuring and thermocuring, which can significantly improve the density and mechanical properties of 3D printed zirconia ceramics.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] The present invention provides a zirconia ceramic slurry, comprising the following components by mass percentage: 75-85% modified zirconia powder, 5-10% resin premix, 4-8% additives, 2-6% photoinitiator, and 0.1-1% thermal initiator;

[0007] The modified zirconia powder is obtained by modifying yttrium-doped zirconia powder with a modifier; the yttrium-doped zirconia powder has a medium particle size of 100–500 nm and a specific surface area of ​​7–9.5 m². 2 / g, the yttrium oxide content is 5-10wt%; the mass of the modifier is 0.4-1% of the mass of the yttrium oxide-doped zirconium oxide powder.

[0008] Preferably, the modifier includes one or more of methacrylic acid, 3-(isobutyryloxy)propyltrimethoxysilane, and stearic acid.

[0009] Preferably, the resin premix comprises, by weight percentage, the following components: 15-40% acrylate oligomers and 60-85% reactive diluent.

[0010] Preferably, the reactive diluent comprises one or more of hydroxyethyl methacrylate, isooctyl acrylate, 1,6-hexanediol diacrylate, triethylene glycol diacrylate, pentaerythritol triacrylate, tetrahydrofuran methyl acrylate, bis(trimethylolpropane)tetraacrylate, and polyethylene glycol diacrylate.

[0011] Preferably, the photoinitiator comprises one or more of 1-hydroxycyclohexylphenyl ketone, bis(2,6-difluoro-3-pyrrolephenyldicyclopentadiene), phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, 2-hydroxy-2-methyl-1-phenyl-1-propanone, diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide, photoinitiator 1300, and camphorquinone.

[0012] Preferably, the thermal initiator includes at least one of organic peroxide initiators such as dicumyl peroxide, benzoyl peroxide, and tert-butanol hydroperoxide.

[0013] Preferably, the additive includes one or more of surfactants, dispersants, or defoamers.

[0014] Preferably, the surfactant comprises one or more of the following: silane coupling agents, polyvinylpyrrolidone, lower alcohols, organic amines, carboxylic acids, carboxylates, sulfates, and sulfonates.

[0015] Preferably, the dispersant includes one or more of stearic acid, oleic acid, polyvinylpyridinium, sodium polyacrylate, polypropoxy quaternary ternary ammonium chloride, ammonium polyacrylate, silane coupling agent, BYK, BYK103, KOS110, KOS163, Solsperse 2000, Digo 685, Shanggao 9030 and Shanggao 9070.

[0016] This invention provides a method for preparing the zirconia ceramic slurry described in the above technical solution, comprising the following steps:

[0017] Modified zirconia powder, resin premix, and additives are mixed to obtain zirconia-resin slurry;

[0018] The zirconia-resin slurry, photoinitiator, and thermal initiator are mixed to obtain a zirconia ceramic slurry.

[0019] This invention provides a 3D printed zirconia ceramic, which is obtained by sequentially performing 3D printing, photocuring, thermocuring, debinding and sintering on a zirconia ceramic slurry;

[0020] The zirconia ceramic slurry is the zirconia ceramic slurry described in the above technical solution or the zirconia ceramic slurry prepared by the preparation method described in the above technical solution.

[0021] Preferably, the density of the photocured preform obtained by photocuring is ≥3.1 g / cm³. 3 ;

[0022] The density of the dual-cured preform obtained by thermosetting is 3.13–3.9 g / cm³. 3 .

[0023] The present invention also provides the application of the zirconia ceramic slurry described in the above technical solution, the zirconia ceramic slurry prepared by the preparation method described in the above technical solution, or the 3D printed zirconia ceramic described in the above technical solution in the preparation of dental restorations.

[0024] This invention controls the particle size, specific surface area, and yttrium oxide content range of zirconia powder. It employs a modifier to modify the zirconia powder, transforming the hydrophilic powder into a hydrophobic surface. This increases the compatibility between the zirconia powder and the resin premix, thereby increasing the solid content of the zirconia ceramic slurry and improving the mechanical properties of the 3D-printed material. The resin premix used in this invention features a simple and safe system composition, low viscosity, and high curing efficiency. It significantly improves the cured strength and density of the printed sample, and further enhances the density through a thermosetting process. This invention, by introducing photoinitiators and thermal initiators and controlling their ratio, significantly improves the double bond conversion efficiency of zirconia ceramic slurry after two curing processes—photocuring and thermal curing. This means more double bonds participate in the polymerization reaction, forming a more complete polymer network structure. This more complete polymer network improves the material's density and hardness, reduces sintering resistance, and results in superior mechanical properties such as flexural strength and durability after final firing, meeting the mechanical performance standards for dental restorations. The zirconia ceramic slurry provided by this invention is applicable to various models of DLP printers using ultraviolet and visible light, offering a wide range of applications and meeting the needs of irregular, personalized, and customized dental material applications.

[0025] This invention provides a method for preparing the zirconia ceramic slurry described in the above technical solution. The preparation method provided by this invention is simple in process, easy to operate, low in energy consumption, low in production cost, green, safe and environmentally friendly, and suitable for industrial production.

[0026] This invention also provides a 3D-printed zirconia ceramic, obtained by sequentially performing 3D printing, photocuring, thermocuring, debinding, and sintering on the zirconia ceramic slurry. The zirconia ceramic slurry used in this invention features high solids content and low viscosity, making it suitable for UV and visible light printers. After 3D printing, photocuring, and thermocuring, the double bond conversion rate is high, significantly improving the hardness, flexural strength, and durability of the 3D-printed zirconia ceramic. Furthermore, this invention adds a thermocuring step after photocuring, further enhancing the polymerization degree of the slurry after curing, increasing the material's density and strength, reducing defects during debinding and sintering, and reducing sintering resistance in subsequent sintering processes. This significantly improves the density and mechanical properties of the 3D-printed zirconia ceramic. The resulting 3D-printed zirconia ceramic exhibits excellent mechanical properties, meeting the mechanical performance standards for dental restorations, and also satisfying the needs of irregular, personalized, and customized applications. Detailed Implementation

[0027] This invention provides a zirconia ceramic slurry, comprising the following components by weight percentage: 75-85% modified zirconia powder, 5-10% resin premix, 4-8% additives, 2-6% photoinitiator, and 0.1-1% thermal initiator;

[0028] The modified zirconia powder is obtained by modifying yttrium-doped zirconia powder with a modifier; the yttrium-doped zirconia powder has a medium particle size of 100–500 nm and a specific surface area of ​​7–9.5 m². 2 / g, the yttrium oxide content is 5-10 wt%; the mass of the modifier is 0.4-1% of the mass of the yttrium oxide-doped zirconium oxide powder.

[0029] The resin premix comprises, by weight percentage: 15-40% acrylate oligomers and 60-85% reactive diluent;

[0030] Unless otherwise specified, the materials and equipment used in this invention are all commercially available products in the field.

[0031] The zirconia ceramic slurry provided by this invention comprises 75-85% modified zirconia powder, preferably 78-85%, and more preferably 80-82%, by weight percentage. In this invention, the modified zirconia powder is obtained by modifying yttrium-doped zirconia powder with a modifier. In this invention, the yttrium-doped zirconia powder has a particle size of 100-500 nm, preferably 150-480 nm, and more preferably 170-450 nm. Excessively large particle size of the yttrium-doped zirconia powder will affect the density and mechanical properties of the final product, while excessively small particle size will reduce the increase in the solid content of the slurry, similarly affecting the density and mechanical properties of the final product. The specific surface area of ​​the yttrium-doped zirconia powder is 7-9.5 m². 2 / g, preferably 7-9m 2 / g, more preferably 7-8.8m 2 / g, an excessively large specific surface area of ​​the yttrium-doped zirconia powder will reduce the increase of slurry solid content, increase slurry viscosity, affect the printability controllability of the finished product, increase the risk of defects, and ultimately affect the performance of the finished product. An excessively small specific surface area will affect the density and mechanical properties of the final product. The yttrium content in the yttrium-doped zirconia powder is 5-10 wt%, preferably 5-9 wt%, more preferably 6-8 wt%. Excessive yttrium content in the yttrium-doped zirconia powder will reduce the mechanical properties of the final product, and too little yttrium content will also reduce the mechanical properties. The yttrium-doped zirconia powder preferably includes 3Y-TZP zirconia powder. This invention, by controlling the particle size, specific surface area, and yttrium content of the yttrium-doped zirconia powder, helps to reduce slurry viscosity, increase slurry solid content, control product defects, and ultimately improve the density and mechanical properties of the final product. In this invention, the modifier preferably includes one or more of methacrylic acid (MAA), 3-(isobutyryloxy)propyltrimethoxysilane (γ-MPS), and stearic acid (SA). In this invention, the particle size of the modified zirconia powder is preferably ≥100 mesh. In this invention, modification with the above-mentioned carboxyl-containing modifier results in the formation of a hydrophobic surface on the hydrophilic zirconia powder, increasing the solubility of the zirconia powder in the resin and increasing the solid content of the zirconia ceramic slurry.

[0032] The zirconia ceramic slurry provided by the present invention comprises, by weight percentage, 2-6% photoinitiator, preferably 3-5%, and more preferably 3-4%. In the present invention, the photoinitiator preferably includes one or more of the following: 1-hydroxycyclohexylphenyl ketone (photoinitiator 184), bis(2,6-difluoro-3-pyrrolephenyl)titanium oxide (photoinitiator 784), phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (photoinitiator 819), 2-hydroxy-2-methyl-1-phenyl-1-propanone (photoinitiator 1173), diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide (photoinitiator TPO), photoinitiator 1300, and camphorquinone.

[0033] The zirconia ceramic slurry provided by the present invention comprises, by mass percentage, 0.1-1%, preferably 0.1-0.7%, and more preferably 0.2-0.6% of a thermal initiator. In the present invention, the thermal initiator preferably comprises an organic peroxide initiator, and more preferably one or more of dicumyl peroxide (CHP), benzoyl peroxide (BPO), and tert-butanol hydroperoxide (TBHP).

[0034] The zirconium oxide ceramic slurry provided by the present invention comprises 5-10% resin premix, preferably 5-8%, and more preferably 5-7%, by mass percentage.

[0035] In this invention, the resin premix preferably comprises, by weight percentage, 15-40% acrylate oligomers, more preferably 15-30%, and even more preferably 20-30%; and 60-85% reactive diluent, more preferably 65-80%, and even more preferably 70-80%. In this invention, the acrylate oligomers preferably comprise one or more of epoxy acrylates, polyester acrylates, and polyurethane acrylates (PUA); the weight-average molecular weight of the acrylate oligomers is preferably 500-5000, more preferably 500-3000. In this invention, the reactive diluent preferably includes one or more of the following: hydroxyethyl methacrylate (HEMA), isooctyl acrylate (EHA), 1,6-hexanediol diacrylate (HDDA), triethylene glycol diacrylate (TEGDA), pentaerythritol triacrylate (PETA), tetrahydrofuran methyl acrylate (THFA), bis(trimethylolpropane)tetraacrylate (Di-TMPTA), and polyethylene glycol diacrylate (PEG(200)DA).

[0036] The zirconia ceramic slurry provided by this invention comprises 4-8% additives by weight percentage, preferably 4.5-7.5%, more preferably 5-7%, and even more preferably 5.5-6%. In this invention, the additives preferably include one or more of surfactants, dispersants, or defoamers, more preferably including dispersants, or a mixture of one or two of surfactants and defoamers with a dispersant. The resin premix used in this invention has the characteristics of simple and safe system composition, low viscosity, high curing efficiency, and can significantly improve the curing strength and density of the printed sample. Further thermal curing can further improve the density of the sample.

[0037] In this invention, the additives, by weight percentage, include 0-40% surfactant, preferably 0-30%, more preferably 0-25%; 50-100% dispersant, more preferably 65-100%, further preferably 70-100%; and 0-13% defoamer, more preferably 0-12%, further preferably 0-10%.

[0038] In this invention, the surfactant preferably comprises one or more of the following: silane coupling agents, polyvinylpyrrolidone, lower alcohols, organic amines, carboxylic acids, carboxylates, sulfates, and sulfonates. In this invention, the silane coupling agent preferably comprises one or more of γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-methacryloyloxypropyltrimethoxysilane. In this invention, the lower alcohol preferably comprises one or more of ethylene glycol, n-butanol, and isopropanol. In this invention, the organic amine preferably comprises one or more of dodecylamine, octadecylamine, and cocoylamine. In this invention, the carboxylic acid preferably comprises succinic acid. In this invention, the carboxylate preferably comprises one or more of sodium oleate, sodium laurate, and sodium stearate. In this invention, the sulfate preferably comprises sodium fatty alcohol polyoxyethylene ether sulfate (AES) and / or sodium dodecyl sulfate. In this invention, the sulfonate preferably comprises sodium dodecylbenzenesulfonate.

[0039] In this invention, the dispersant preferably includes one or more of stearic acid, oleic acid, polyvinylpyridinium, sodium polyacrylate, polypropoxy quaternary ternary ammonium chloride, ammonium polyacrylate, silane coupling agent, BYK, BYK103, KOS110, KOS163, Solsperse2000, Digo 685, Shanggao 9030, and Shanggao 9070. In this invention, the silane coupling agent includes one or more of γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-methacryloyloxypropyltrimethoxysilane.

[0040] In this invention, the defoamer preferably includes one or more of n-octanol, BYK-1790, BYK-1794, DIG-Airex920, AKN-39203, and AKN-3386.

[0041] The present invention does not have any particular limitation on the preparation method of the resin premix liquid; it is sufficient to mix the components of the aforementioned resin premix liquid evenly.

[0042] This invention provides a method for preparing the zirconia ceramic slurry described in the above technical solution, comprising the following steps:

[0043] Modified zirconia powder, resin premix, and additives are mixed to obtain zirconia-resin slurry;

[0044] The zirconia-resin slurry, photoinitiator, and thermal initiator are mixed to obtain a zirconia ceramic slurry.

[0045] The preparation method of modified zirconia powder will be explained in detail below.

[0046] In this invention, the method for preparing the modified zirconia powder preferably includes the following steps: mixing yttrium-doped zirconia powder, an alcohol solvent and a modifier, ball milling the mixture and then drying it to obtain the modified zirconia powder.

[0047] In this invention, the alcohol solvent preferably includes anhydrous ethanol. In this invention, the mass ratio of the zirconium oxide powder to the alcohol solvent is preferably 1–1.2:1.8–2, more preferably 1–1.1:1.9–2.

[0048] In this invention, the mass ratio of zirconium oxide powder to modifier is preferably 1:0.004 to 0.01, more preferably 1:0.005 to 0.006.

[0049] In this invention, the mixing of zirconium oxide powder, alcohol solvent, and modifier preferably includes: mixing the modifier with an alcohol solvent to obtain a modifier solution; and mixing the modifier solution with zirconium oxide powder.

[0050] In this invention, the ball milling media used for the ball milling modification preferably include large grinding balls and small grinding balls. In this invention, the particle size of the large grinding balls is preferably 10-15 mm, and the material of the large grinding balls preferably includes one or more of zirconium oxide, alumina, and silicon nitride; the mass ratio of zirconium oxide powder to large grinding balls is preferably 1-1.2:1.8-2, more preferably 1-1.1:1.9-2. In this invention, the particle size of the small grinding balls is preferably 5-10 mm; the material of the small grinding balls preferably includes one or more of zirconium oxide, alumina, and silicon nitride; the mass ratio of zirconium oxide powder to small grinding balls is preferably 1-1.2:1-1.2, more preferably 1-1.1:1-1.1. In this invention, the ball milling speed is preferably 300-900 r / min, more preferably 400-700 r / min; the ball milling time is preferably 2-12 h, more preferably 2-6 h.

[0051] In this invention, the drying temperature is preferably 60-80°C, more preferably 70°C. This invention does not have a special limitation on the drying time; drying to constant weight is sufficient. The drying is preferably carried out in a forced-air drying oven.

[0052] After the drying process is completed, the present invention preferably further includes: grinding the obtained dried powder and sieving it through a 100-mesh sieve, with the undersize portion being modified zirconia powder. In the present invention, after ball milling modification, the hydrophilic zirconia powder has a hydrophobic surface, thereby increasing the solubility of zirconia powder and resin, and increasing the solid content of zirconia ceramic slurry.

[0053] After obtaining modified zirconia powder, the present invention mixes the modified zirconia powder, resin premix and additives to obtain zirconia-resin slurry.

[0054] In this invention, the mixing of the modified zirconia powder, resin premix, and additives is preferably as follows: the resin premix and additives are mixed to obtain a mixture; the modified zirconia powder is added to the mixture under a first ball milling condition; and after the modified zirconia powder is added, a second ball milling is performed. In this invention, the modified zirconia powder is preferably added in 1 to 6 portions, more preferably 2 to 5 portions, and even more preferably 3 to 4 portions. In this invention, the rotation speed of the first and second ball milling is independently preferably 500 to 900 r / min, more preferably 600 to 800 r / min, and even more preferably 700 r / min; the time of the first ball milling (i.e., the total time for adding the modified zirconia powder) is preferably 4 to 18 hours, more preferably 5 to 15 hours, and even more preferably 6 to 10 hours; the time of the second ball milling is preferably 4 to 12 hours, more preferably 5 to 10 hours, and even more preferably 6 to 8 hours, resulting in a uniform suspension of the modified zirconia-resin mixture.

[0055] After obtaining the zirconia-resin slurry, the present invention mixes the zirconia-resin slurry, a photoinitiator, and a thermal initiator to obtain a zirconia ceramic slurry. In the present invention, the mixing is preferably ball milling, the ball milling speed is preferably 500-900 r / min, more preferably 600-800 r / min, and even more preferably 700 r / min; the ball milling time is preferably 1-4 h, more preferably 1.5-3.5 h, and even more preferably 2-3 h; the ball milling is intermittent ball milling, which preferably includes ball milling for 30-90 min (more preferably 50-60 min), stopping for 5-15 min (more preferably 8-10 min), and then performing the next ball milling.

[0056] After the mixing is completed, the present invention preferably further includes degassing the resulting zirconia-resin-dual initiator slurry to obtain a zirconia ceramic slurry. In this invention, the degassing treatment is preferably vacuum degassing, and the pressure of the vacuum degassing treatment is preferably -0.1 to 0.1 MPa, more preferably -0.1 to 0 MPa, and even more preferably -0.1 MPa. The present invention does not have a specific limitation on the time of the degassing treatment; the degassing treatment continues until no obvious bubbles are generated on the surface of the slurry, specifically for 3 to 6 hours, more preferably 4 to 5 hours. In this invention, the zirconia ceramic slurry is preferably stored in a light-proof bottle to avoid light.

[0057] This invention provides a 3D printed zirconia ceramic, which is obtained by sequentially performing 3D printing, photocuring, thermocuring, debinding and sintering on a zirconia ceramic slurry; the zirconia ceramic slurry is the zirconia ceramic slurry described in the above technical solution or the zirconia ceramic slurry prepared by the preparation method described in the above technical solution.

[0058] This invention does not impose any special limitations on the 3D printing process. The printer is leveled and calibrated according to actual needs, and then the zirconia ceramic slurry is placed in the material tank of the 3D printing equipment. The 3D printing parameters are set according to the actual size and precision requirements of the printed sample. In a specific embodiment of this invention, the light source used for 3D printing and photopolymerization preferably includes visible light or ultraviolet light, with the wavelength of the light source preferably being 385–460 nm; the wavelength of the visible light is preferably 430–460 nm, more preferably 450 nm; the wavelength of the ultraviolet light is preferably 385–410 nm, more preferably 405 nm; and the light intensity for 3D printing and photopolymerization is preferably 30–70 mV / cm. 2 More preferably 40–50 mV / cm 2 The photocuring time is preferably 4–20 s, more preferably 6–15 s. In this invention, the density of the photocured preform obtained by photocuring is preferably ≥3.1 g / cm³.3 More preferably, it is 3.1–3.7 g / cm³. 3 .

[0059] After photocuring, the present invention preferably further includes: removing the photocured preform using a special tool without damaging the printing substrate, removing the support and cleaning it with a cleaning solution and / or an ethanol aqueous solution, and then blowing away the residual cleaning solution and / or ethanol aqueous solution with a spray gun (i.e., drying) to prevent the residual cleaning solution and / or ethanol aqueous solution from corroding the sample. In the present invention, the volume fraction of ethanol in the ethanol aqueous solution is preferably 60-100%, more preferably 70-90%.

[0060] In this invention, the thermosetting is preferably carried out in a low-temperature resistance furnace. In this invention, the thermosetting is preferably programmed thermosetting, which preferably includes: starting from room temperature, heating to 70-75°C (more preferably 71-74°C, more preferably 72-73°C) at a rate of 0.1-0.5°C / min (more preferably 0.1-0.4°C / min, even more preferably 0.2-0.3°C / min), holding at that temperature for 50-70 min (more preferably 55-65 min, even more preferably 60 min), and then heating to 80-85°C (more preferably 81-84°C, even more preferably 0.1-0.5°C / min (more preferably 0.1-0.4°C / min, even more preferably 0.2-0.3°C / min) at a rate of 0.1-0.5°C / min (more preferably 0.1-0.4°C / min, even more preferably 0.2-0.3°C / min). The temperature is preferably 82-83℃, then held for 50-70 min (more preferably 55-65 min, even more preferably 60 min), then increased to 90-95℃ (more preferably 91-94℃, even more preferably 92-93℃) at 0.1-0.5℃ / min (more preferably 0.1-0.4℃ / min, even more preferably 0.2-0.3℃ / min), held for 100-150 min, then increased to 95-100℃ (more preferably 96-99℃, even more preferably 97-98℃) at 0.1-0.5℃ / min (more preferably 0.1-0.4℃ / min, even more preferably 0.2-0.3℃ / min), and held for 100-150 min. The temperature is increased to 100-105°C (more preferably 101-104°C, more preferably 102-103°C) at a rate of 0.1-0.5°C / min (more preferably 0.1-0.4°C / min, more preferably 0.2-0.3°C / min) for 50-70 minutes (more preferably 55-65 minutes, more preferably 60 minutes), and then increased to 105-110°C (more preferably 101-104°C, more preferably 102-103°C) at a rate of 0.1-0.5°C / min (more preferably 0.1-0.4°C / min, more preferably 0.2-0.3°C / min) for 50-70 minutes (more preferably 55-65 minutes, more preferably 60 minutes) at a rate of 0.1-0.5°C / min (more preferably 0.1-0.4°C / min, more preferably 0.2-0.3°C / min) for 50 minutes (more preferably 110-140 minutes, more preferably 120-130 minutes). After heating to 106–109°C, more preferably 107–108°C, hold for 50–70 min (more preferably 55–65 min, more preferably 60 min), then heat to 110–115°C (more preferably 111–114°C, more preferably 112–113°C) at a rate of 0.1–0.5°C / min (more preferably 0.1–0.4°C / min, more preferably 0.2–0.3°C / min), hold for 80–120 min (more preferably 90–110 min, more preferably 100 min), and then heat to 0.1–0.5°C / min (more preferably 0.1–0.4°C / min, more preferably 0.2–0.5°C / min).The temperature is increased to 115–120°C (more preferably 116–119°C, even more preferably 117–118°C) at a rate of 3°C / min, held at that temperature for 100–150 min (more preferably 110–140 min, even more preferably 120–130 min), and then cooled to room temperature in the furnace.

[0061] In this invention, the density of the dual-cured preform obtained by thermosetting is preferably 3.13–3.9 g / cm³. 3 More preferably, it is 3.3–3.9 g / cm³. 3 After thermosetting, the density of the dual-cured preform increased by 1 to 10% compared to the density of the photocured preform.

[0062] In this invention, the degreasing is preferably programmed degreasing, which preferably includes: starting from room temperature, heating to 170-200°C (more preferably 180-190°C) at a rate of 0.2-1.5°C / min (more preferably 0.5-1°C / min), holding at that temperature for 120-180 min (more preferably 130-150 min), then heating to 325-345°C (more preferably 330-340°C) at a rate of 1-1.5°C / min (more preferably 1.2-1.3°C / min), holding at that temperature for 120-180 min (more preferably 130-150 min), and then heating at a rate of 1-1.5°C / min (more preferably 1.2-1.3°C / min). The temperature is increased to 430-450°C (more preferably 435-440°C) at a rate of 0.3°C / min, and then held for 120-180 min (more preferably 130-150 min). Then the temperature is increased to 600-630°C (more preferably 610-620°C) at a rate of 1-1.5°C / min (more preferably 1.2-1.3°C / min), and then held for 240-300 min (more preferably 250-270 min). Then the temperature is increased to 1000-1100°C (more preferably 1030-1050°C) at a rate of 1-3°C / min (more preferably 2°C / min), and then held for 60-90 min (more preferably 70-80 min).

[0063] After the degreasing is completed, the present invention preferably further includes cooling the obtained degreased sample to room temperature to obtain a degreased sample. In the present invention, the cooling preferably includes cooling to 200-400°C (more preferably 300°C) at a rate of 1-3°C / min (more preferably 2°C / min) and then cooling to room temperature in the furnace.

[0064] In this invention, the sintering temperature is preferably programmed sintering, which preferably includes: starting from room temperature, heating at a rate of 2-7°C / min (more preferably 3-5°C / min) to 900-1000°C (more preferably 930-950°C), holding at that temperature for 30-60 min (more preferably 40-50 min), and then heating at a rate of 3-5°C / min (more preferably 4-4.5°C / min) to 1520-1550°C (more preferably 1530-1540°C) and holding at that temperature for 120-150 min (more preferably 130-140 min).

[0065] After the sintering is completed, the present invention preferably further includes cooling the obtained sintered sample to room temperature to obtain 3D printed zirconia ceramic. In the present invention, the cooling preferably includes cooling to 700-900°C (more preferably 800°C) at a rate of 5-15°C / min (more preferably 10°C / min) and then cooling to room temperature in the furnace.

[0066] Ceramic photopolymerization 3D printing technology relies on the selective photopolymerization of ceramic slurry under ultraviolet light or other light sources. Its main drawback is that the presence of ceramic powder in the slurry causes refraction, scattering, and absorption of incident light, significantly reducing the degree of photopolymerization and resulting in a decrease in slurry thickness. This affects the bonding between adjacent layers during printing and leads to defects such as delamination during debinding and sintering. This invention adds a thermal curing process after 3D printing and photopolymerization, employing a dual-curing system of photopolymerization and thermal curing. This further enhances the polymerization degree of the slurry, increases density, and reduces defects during debinding and sintering, thereby significantly improving the mechanical properties of 3D-printed zirconia ceramics. By strictly controlling the debinding and sintering procedures (temperature, time, heating rate), this invention ensures that the debinding and sintering processes do not crack or deform, further improving the mechanical properties of 3D-printed zirconia ceramics. It is suitable for ultraviolet and visible light printers, and the resulting 3D-printed zirconia ceramics exhibit high mechanical properties, meeting the mechanical performance standards for dental restorations, especially long dental bridge restorations.

[0067] In this invention, the density of the 3D printed zirconia ceramic is preferably ≥99%, more preferably 99.2-99.4%; the flexural strength of the 3D printed zirconia ceramic is preferably ≥910MPa, more preferably 910-927MPa; and the Vickers hardness of the 3D printed zirconia ceramic is preferably ≥12.5GPa, more preferably 12.9-13.1GPa.

[0068] This invention also provides the application of the zirconia ceramic slurry described in the above-described technical solutions, the zirconia ceramic slurry prepared by the preparation method described in the above-described technical solutions, or the 3D-printed zirconia ceramic described in the above-described technical solutions in the preparation of dental restorations. In this invention, the dental restoration preferably includes one or more of the following: inner crown, full crown, inlay, and bridge.

[0069] To further illustrate the present invention, the following detailed descriptions of zirconia ceramic slurry, its preparation method and application, and 3D printed zirconia ceramics and their applications are provided in conjunction with embodiments, but these should not be construed as limiting the scope of protection of the present invention.

[0070] In the following examples, the weight-average molecular weight of polyurethane acrylate (PUA) is 3000, and the weight-average molecular weight of 1,6-hexanediol diacrylate (HDDA) is 238.

[0071] Example 1

[0072] (1) Preparation of modified zirconia powder

[0073] The dried 3Y zirconium oxide powder (with a particle size of 450 nm and a specific surface area of ​​8.5 m²) was then processed. 2 Add / g) to a ball mill jar, along with anhydrous ethanol and methacrylic acid (MAA). Prepare 10mm and 7mm zirconia grinding balls to achieve a mass ratio of anhydrous ethanol: powder: large grinding ball: small grinding ball = 2:1:2:1. Add the powder, solvent, and grinding balls to the ball mill jar separately and stir until homogeneous. Then, place the prepared ball mill jar on a ball mill for ball milling (4 hours). Finally, place the homogeneous mixture in a forced-air drying oven to dry (70℃). The dried powder is then ground in a mortar and pestle and passed through a 100-mesh sieve; the undersize portion is modified zirconia powder. The MAA content is 0.5% of the dry weight of the 3Y zirconia powder; the mass ratio of anhydrous ethanol: dried 3Y zirconia powder: large grinding ball: small grinding ball = 2:1:2:1; and the rotation speed of each ball mill is 700 r / min.

[0074] (2) Preparation of zirconia ceramic slurry

[0075] The zirconia ceramic slurry, by weight percentage, comprises: 83% modified zirconia powder, 8.1% resin premix, 4.4% additives (0.8% succinic acid, 3.5% dispersant BYK103, 0.1% defoamer AKN-3386), 3.5% photoinitiator, and 1% thermal initiator cumene hydroperoxide (CHP).

[0076] Resin premix: The mass ratio of polyurethane acrylate (PUA), 1,6-hexanediol diacrylate (HDDA), and polyethylene glycol diacrylate (PEG(200)DA) is 1.5:5:1.6;

[0077] Resin premix - additive mixture: Polyurethane acrylate (PUA), 1,6-hexanediol diacrylate (HDDA), polyethylene glycol diacrylate (PEG(200)DA), succinic acid, dispersant BYK103 and defoamer AKN-3386 are mixed evenly in a mass ratio of 1.5:5:1.6:0.8:3.5:0.1 to obtain the resin premix - additive mixture.

[0078] Under stirring conditions, 80% of the modified zirconia powder was first added to the resin premix-additive mixture and placed in a ball mill. The remaining modified zirconia powder was added in three portions under ball milling conditions (600 r / min). After the modified zirconia powder was added, ball milling continued at 600 r / min for 8 hours. After the ball milling was uniform, photoinitiator and thermal initiator were added, and ball milling continued for 3 hours (pausing for 10 minutes after each hour of ball milling). After the ball milling was completed, the mixture was placed in a vacuum defoamer and vacuum defoamed for 3 hours under a vacuum degree of -0.1 MPa to obtain zirconia ceramic slurry.

[0079] (3) Photopolymer 3D printing (one-time photopolymerization)

[0080] Visible light band printing: at a light intensity of 40mV / cm 2 Under a visible light source with a wavelength of 450 nm, zirconia ceramic slurry was 3D printed in layers with a thickness of 25 μm, followed by exposure and curing for 8 seconds to obtain a photocured green body (density 3.30 g / cm³). 3 );

[0081] Or ultraviolet light printing: at a light intensity of 45mV / cm 2 Under a surface light source with an ultraviolet wavelength of 405 nm, zirconia ceramic slurry was 3D printed in layers with a thickness of 40 μm, followed by exposure and curing for 15 seconds to obtain a photocured green body (density 3.35 g / cm³). 3 ).

[0082] (4) Sample disassembly, cleaning and drying

[0083] Remove the photocured preform from the printing platform and clean it with cleaning fluid or alcohol. To prevent residual cleaning fluid from corroding the sample, blow off the residual cleaning fluid with a spray gun after cleaning.

[0084] (5) Thermosetting (secondary thermosetting)

[0085] Programmed thermosetting was performed using a low-temperature resistance furnace: starting from room temperature, the temperature was increased to 75°C at a rate of 0.2°C / min and held for 60 min; then increased to 85°C at a rate of 0.1–0.2°C / min and held for 60 min; next, increased to 95°C at a rate of 0.1–0.2°C / min and held for 100 min; then increased to 100°C at a rate of 0.1–0.2°C / min and held for 120 min; finally, the temperature was increased to... The temperature was initially set at 105℃ and held for 60 min. Then, the temperature was increased to 110℃ at a rate of 0.1–0.2℃ / min and held for 60 min. Next, the temperature was increased to 115℃ at a rate of 0.1–0.2℃ / min and held for 90 min. Finally, the temperature was increased to 120℃ at a rate of 0.1–0.2℃ / min and held for 120 min. The mixture was then cooled to room temperature in the furnace to obtain a dual-cured preform. When the preform obtained by visible light printing was used as raw material, the density of the dual-cured preform was 3.62 g / cm³. 3 When using a photocurable preform obtained by ultraviolet light printing as raw material, the density of the dual-curing preform is 3.68 g / cm³. 3 .

[0086] (6) Degreasing and sintering

[0087] The dual-cured preform was placed in a debinding oven for degreasing (segmented debinding): starting from room temperature, the temperature was increased to 170℃ at a rate of 0.8℃ / min and held for 120 min; then increased to 325℃ at a rate of 1℃ / min and held for 180 min; then increased to 430℃ at a rate of 1℃ / min and held for 180 min; then increased to 630℃ at a rate of 1.2℃ / min and held for 240 min; then increased to 1000℃ at a rate of 2℃ / min and held for 60 min; and finally decreased to 300℃ at a rate of 2℃ / min and cooled to room temperature in the oven to obtain the degreased sample.

[0088] After degreasing, final sintering is performed: the degreased sample is heated from room temperature to 900℃ at a rate of 4℃ / min and held for 60min, then heated to 1530℃ at a rate of 3℃ / min and held for 120min, and then cooled to 800℃ at a rate of 10℃ / min and cooled to room temperature in the furnace to obtain 3D printed zirconia ceramic.

[0089] The zirconia ceramic slurry prepared in this embodiment has a solid content of 83 wt% and is prepared at 20°C for 30 seconds. -1With a viscosity of 22 Pa·s at the shear rate, the double bond conversion rate of the dual-cured preform (printed using UV light in photopolymerization 3D printing) reached 89.92% after two curing cycles. The density of the 3D-printed zirconia ceramic (printed using UV light in photopolymerization 3D printing) was 99.4%, exhibiting excellent physicochemical properties, a flexural strength of 927 MPa, and a Vickers hardness of 13.1 GPa, meeting the clinical requirements for dental restoration. When photopolymerization 3D printing is performed using visible light, the technical effects of the dual-cured preform and the 3D-printed zirconia ceramic are similar.

[0090] Example 2

[0091] The zirconia ceramic slurry and 3D-printed zirconia ceramics were prepared according to the method of Example 1, with the only difference from Example 1 being:

[0092] In step (2), succinic acid is replaced with n-butanol;

[0093] The zirconia ceramic slurry, by mass percentage, comprises: 82.5% modified zirconia powder, 8.1% resin premix, 4.4% additives (0.8% succinic acid, 3.5% dispersant BYK103, 0.1% defoamer AKN-3386), 4% a mixture of photoinitiator 819 and photoinitiator 784, and 1% thermal initiator benzoyl peroxide (BPO), wherein the mass ratio of photoinitiator 819 to photoinitiator 784 is 1.5:1.

[0094] In step (3) of visible light printing, the light intensity is 50mV / cm. 2 With an exposure time of 6 seconds, the density of the photocured preform obtained by visible light printing is 3.25 g / cm³. 3 In ultraviolet light printing, the light intensity is 40 mV / cm. 2 With an exposure time of 13 seconds, the density of the photocured preform obtained by ultraviolet light printing was 3.20 g / cm³. 3 ;

[0095] In step (5), when the photocurable preform obtained by printing in the visible light band is used as raw material, the density of the dual-curing preform is 3.52 g / cm³. 3 When using a photocurable preform obtained by ultraviolet light printing as raw material, the density of the dual-curing preform is 3.48 g / cm³. 3 ;

[0096] In step (6), degreasing: starting from room temperature, the temperature is increased to 175℃ at a rate of 0.8℃ / min and held for 120min, then increased to 340℃ at a rate of 1℃ / min and held for 180min, then increased to 440℃ at a rate of 1℃ / min and held for 180min, then increased to 630℃ at a rate of 1.2℃ / min and held for 240min, then increased to 1000℃ at a rate of 2℃ / min and held for 60min, and then decreased to 300℃ at a rate of 2℃ / min and cooled to room temperature in the furnace.

[0097] The zirconia ceramic slurry prepared in this embodiment has a solid content of 82.5 wt% and is prepared at 20°C for 30 seconds. -1 With a viscosity of 21 Pa·s at the shear rate, the double bond conversion rate of the dual-cured preform (photopolymerized 3D printing in the visible light band) reached 88.75% after two curing cycles. The density of the 3D-printed zirconia ceramic (photopolymerized 3D printing in the visible light band) was 99.3%, exhibiting excellent physicochemical properties, a flexural strength of 910 MPa, and a Vickers hardness of 12.9 GPa, meeting the clinical requirements for dental restoration. The flexural strength was tested using a three-point bending test. When photopolymerized 3D printing is performed in the visible light band, the technical effects of the dual-cured preform and the 3D-printed zirconia ceramic are similar.

[0098] Example 3

[0099] The zirconia ceramic slurry and 3D-printed zirconia ceramics were prepared according to the method of Example 1, with the only difference from Example 1 being:

[0100] In step (2), the zirconia ceramic slurry, by mass percentage, contains: 84% modified zirconia powder, 7.1% resin premix, 4.8% additives (0.8% succinic acid, 4% dispersant BYK103), 3.5% photoinitiator, and 0.6% thermal initiator cumene hydroperoxide (CHP).

[0101] Resin premix: The mass ratio of polyurethane acrylate (PUA), 1,6-hexanediol diacrylate (HDDA), and polyethylene glycol diacrylate (PEG(200)DA) is 1.5:4:1.6;

[0102] Resin premix - additive mixture: Polyurethane acrylate (PUA), 1,6-hexanediol diacrylate (HDDA), polyethylene glycol diacrylate (PEG(200)DA), succinic acid, and dispersant BYK103 are mixed in a mass ratio of 1.5:4:1.6:0.8:4.

[0103] In step (3) of visible light printing, the light intensity is 55mV / cm. 2With an exposure time of 6 seconds, the density of the photocured preform obtained by visible light printing is 3.40 g / cm³. 3 In ultraviolet light printing, the light intensity is 45mV / cm. 2 With an exposure time of 15 seconds, the density of the photocured preform obtained by ultraviolet light printing was 3.46 g / cm³. 3 ;

[0104] In step (5), when the photocurable preform obtained by printing in the visible light band is used as raw material, the density of the dual-curing preform is 3.78 g / cm³. 3 When using a photocurable preform obtained by ultraviolet light printing as raw material, the density of the dual-curing preform is 3.85 g / cm³. 3 .

[0105] The zirconia ceramic slurry prepared in this embodiment has a solid content of 84 wt% and is prepared at 20°C for 30 seconds. -1 The viscosity at the shear rate is 23.5 Pa·s. After two curing cycles, the double bond conversion rate of the dual-cured preform (photopolymerized 3D printing in the visible light band) reaches 88.95%, and the density of the 3D-printed zirconia ceramic (photopolymerized 3D printing in the visible light band) is 99.4%. It exhibits excellent physicochemical properties, with a flexural strength of 950 MPa and a Vickers hardness of 13.2 GPa, meeting the clinical requirements for dental restoration. When photopolymerized 3D printing is performed in the visible light band, the technical effects of the dual-cured preform and the 3D-printed zirconia ceramic are similar.

[0106] Comparative Example 1

[0107] No thermal initiator is added; the resin premix is ​​used to make up 100% of the product, and there is no thermal curing step.

[0108] The zirconia ceramic slurry and 3D-printed zirconia ceramics were prepared according to the method of Example 1, with the only difference from Example 1 being:

[0109] In step (2), the mass ratio of the resin premix (polyurethane acrylate (PUA), 1,6-hexanediol diacrylate (HDDA) and polyethylene glycol diacrylate (PEG(200)DA)) is 1.5:6:1.6.

[0110] Zirconia ceramic slurry, by mass percentage: modified zirconia powder 83%, resin premix 9.1%, additives 4.4% (succinic acid 0.8%, dispersant BYK103 3.5%, defoamer AKN-3386 0.1%), photoinitiator 819 3.5%;

[0111] Resin premix - additive - mixture: The mass ratio of polyurethane acrylate (PUA), 1,6-hexanediol diacrylate (HDDA), polyethylene glycol diacrylate (PEG(200)DA), succinic acid, dispersant BYK103 and defoamer AKN-3386 is 1.5:6:1.6:0.8:3.5:0.1;

[0112] The density of the photocured preform obtained by visible light band printing in step (3) is 3.28 g / cm³. 3 The density of the photocured preform obtained by ultraviolet light printing is 3.32 g / cm³. 3 ;

[0113] The solid content of the zirconia ceramic slurry prepared in this comparative example was 83 wt%, and it was prepared at 20°C for 30 seconds. -1 The viscosity at the shear rate was 18 Pa·s. After one photocuring, the double bond conversion rate of the photocured preform (photocuring 3D printing in the visible light band) reached 79.24%, and the density of the 3D-printed zirconia ceramic (photocuring 3D printing in the visible light band) was 98.5%. It exhibited excellent physicochemical properties, with a flexural strength of 508 MPa and a Vickers hardness of 11.2 GPa. Compared with Example 1, the mechanical properties of the material were significantly reduced. When photocuring 3D printing was performed in the visible light band, the technical effects of the photocured preform and the 3D-printed zirconia ceramic were similar.

[0114] Comparative Example 2

[0115] No thermal initiator is added, and there is no thermal curing step.

[0116] The zirconia ceramic slurry and 3D-printed zirconia ceramics were prepared according to the method of Example 1, with the only difference from Example 2:

[0117] In step (2), the mass ratio of the resin premix (polyurethane acrylate (PUA), 1,6-hexanediol diacrylate (HDDA) and polyethylene glycol diacrylate (PEG(200)DA)) is 1.5:6:1.6.

[0118] The zirconia ceramic slurry, by weight percentage, comprises: 82.5% modified zirconia powder, 9.1% resin premix, 4.9% additives (0.8% n-butanol, 4% dispersant BYK103, 0.1% defoamer AKN-3386), and 3.5% a mixture of photoinitiator 819 and photoinitiator 784 (819:784 mass ratio = 1.5:1).

[0119] Resin premix - additive mixture: The mass ratio of polyurethane acrylate (PUA), 1,6-hexanediol diacrylate (HDDA), polyethylene glycol diacrylate (PEG(200)DA), succinic acid, dispersant BYK103 and defoamer AKN-3386 is 1.5:6:1.6:0.8:4:0.1;

[0120] The density of the photocured preform obtained by visible light band printing in step (3) is 3.25 g / cm³. 3 The density of the photocured preform obtained by ultraviolet light printing is 3.20 g / cm³. 3 ;

[0121] The solid content of the zirconia ceramic slurry prepared in this comparative example was 82.5 wt%, and it was prepared at 20°C for 30 seconds. -1 The viscosity at the shear rate is 18.5 Pa·s. After one photocuring, the double bond conversion rate of the photocured preform (photocuring 3D printing is done in the visible light band) reaches 78.35%. The density of the 3D printed zirconia ceramic (photocuring 3D printing is done in the visible light band) is 98.3%. It has excellent physical and chemical properties, with a flexural strength of 469 MPa and a Vickers hardness of 11.0 GPa. However, a small number of defects such as cracks and pores are generated. Compared with Example 1, the mechanical properties of the material are significantly reduced.

[0122] Comparative Example 3

[0123] The zirconia ceramic slurry and 3D-printed zirconia ceramics were prepared according to the method of Example 1, with the only difference from Example 1 being:

[0124] In step (1), the 3Y zirconium oxide powder has a particle size of 400 nm and a specific surface area of ​​10.2 m². 2 / g);

[0125] In step (2), the zirconia ceramic slurry, by mass percentage, contains: 80% modified zirconia powder, 11.1% resin premix, 4.4% additives (0.8% succinic acid, 3.5% dispersant BYK103, 0.1% defoamer AKN-3386), 3.5% photoinitiator, and 1% thermal initiator cumene hydroperoxide (CHP).

[0126] The density of the photocured preform obtained by visible light band printing in step (3) is 3.18 g / cm³. 3 The density of the photocured preform obtained by ultraviolet light printing is 3.17 g / cm³. 3 ;

[0127] In step (5), when the photocurable preform obtained by printing in the visible light band is used as raw material, the density of the dual-curing preform is 3.23 g / cm³. 3When using a photocurable preform obtained by ultraviolet light printing as raw material, the density of the dual-curing preform is 3.22 g / cm³. 3 .

[0128] The zirconia ceramic slurry prepared in this comparative example had a solid content of 80 wt% and was prepared at 20°C for 30 seconds. -1 The viscosity at the shear rate is 23.5 Pa·s. After two curing cycles, the double bond conversion rate of the double-cured preform (photocuring 3D printing is done in the visible light band) reaches 78%. The density of the 3D printed zirconia ceramic (photocuring 3D printing is done in the visible light band) is 97.2%. It has excellent physical and chemical properties, with a flexural strength of 350 MPa and a Vickers hardness of 10.5 GPa. A small number of defects such as cracks and pores are generated. Compared with Example 1, the slurry solid content is significantly reduced, the viscosity is increased, and the density and mechanical properties of the material are also significantly reduced.

[0129] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, not all embodiments. People can obtain other embodiments based on the present invention without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A zirconia ceramic slurry, characterized in that, By weight percentage, it comprises the following components: 75-85% modified zirconia powder, 5-10% resin premix, 4-8% additives, 2-6% photoinitiator, and 0.1-1% thermal initiator; The modified zirconia powder is obtained by modifying yttrium-doped zirconia powder with a modifier; the yttrium-doped zirconia powder has a particle size of 100~500nm and a specific surface area of ​​7~9.5m². 2 / g, the yttrium oxide content is 5~10wt%; the modifier includes one or more of methacrylic acid, 3-(isobutenoyloxy)propyltrimethoxysilane and stearic acid; the mass of the modifier is 0.4~1% of the mass of the yttrium oxide-doped zirconium oxide powder; The resin premix comprises, by weight percentage, the following components: 15-40% acrylate oligomers and 60-85% reactive diluent; wherein the acrylate oligomers are one or more of epoxy acrylates, polyester acrylates, and polyurethane acrylates. The reactive diluent is one or more of the following: hydroxyethyl methacrylate, isooctyl acrylate, 1,6-hexanediol diacrylate, triethylene glycol diacrylate, pentaerythritol triacrylate, tetrahydrofuran methyl acrylate, bis(trimethylolpropane)tetraacrylate, and polyethylene glycol diacrylate.

2. The zirconia ceramic slurry according to claim 1, characterized in that, The photoinitiator includes one or more of 1-hydroxycyclohexylphenyl ketone, bis(2,6-difluoro-3-pyrrolephenyldicyclopentadiene), phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, 2-hydroxy-2-methyl-1-phenyl-1-propanone, diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide, photoinitiator 1300, and camphorquinone.

3. The zirconia ceramic slurry according to claim 1, characterized in that, The thermal initiator includes an organic peroxide initiator, wherein the organic peroxide initiator is at least one of dicumyl peroxide, benzoyl peroxide, and tert-butanol hydroperoxide.

4. The zirconia ceramic slurry according to claim 1, characterized in that, The additives include one or more of surfactants, dispersants, or defoamers.

5. The zirconia ceramic slurry according to claim 4, characterized in that, The surfactants include one or more of the following: silane coupling agents, polyvinylpyrrolidone, lower alcohols, organic amines, carboxylic acids, carboxylates, sulfates, and sulfonates.

6. The zirconia ceramic slurry according to claim 4, characterized in that, The dispersant includes one or more of stearic acid, oleic acid, polyvinylpyridinium, sodium polyacrylate, polypropoxy quaternary ternary ammonium chloride, ammonium polyacrylate, silane coupling agent, BYK, BYK103, KOS110, KOS163, Solsperse 2000, Digo 685, Shanggao 9030 and Shanggao 9070.

7. A method for preparing the zirconia ceramic slurry according to any one of claims 1 to 6, characterized in that, Includes the following steps: Modified zirconia powder, resin premix, and additives are mixed to obtain zirconia-resin slurry; The zirconia-resin slurry, photoinitiator, and thermal initiator are mixed to obtain a zirconia ceramic slurry.

8. A 3D-printed zirconia ceramic, characterized in that, It is obtained by sequentially 3D printing, photocuring, thermocuring, debinding and sintering zirconia ceramic slurry; The zirconia ceramic slurry is the zirconia ceramic slurry according to any one of claims 1 to 6 or the zirconia ceramic slurry prepared by the preparation method according to claim 7.

9. The 3D-printed zirconia ceramic according to claim 8, characterized in that, The density of the photocured preform obtained by photocuring is ≥3.1 g / cm³. 3 ; The density of the dual-cured preform obtained by thermosetting is 3.13~3.9 g / cm³. 3 .

10. The application of the zirconia ceramic slurry according to any one of claims 1 to 6, the zirconia ceramic slurry prepared by the preparation method according to claim 7, or the 3D printed zirconia ceramic according to any one of claims 8 to 9 in the preparation of dental restorations.