A β-tricalcium phosphate-based photocurable ceramic slurry and its preparation method

Abstract

This invention discloses a β-tricalcium phosphate-based photocurable ceramic slurry and its preparation method. By volume, it comprises the following components: 66-75 parts modified ceramic powder, 25-30 parts resin premix, and a dispersant comprising 10-20% of the modified ceramic powder by mass. The modified ceramic powder is KH560 or KH570 modified ceramic powder. The mass ratio of β-tricalcium phosphate, hydroxyapatite, and 3Y-TZP is 4-10:2-6:1. The average particle size of β-tricalcium phosphate is 6-12 μm and / or 1-4 µm; the average particle size of HA particles is 1-4 µm and / or 300-500 nm; and the average particle size of 3Y-TZP particles is 300-500 nm and / or 80-120 nm. While ensuring high solids content, high dispersion stability and good rheological properties, it can also achieve degreasing and sintering densification, effectively improve the mechanical stability of green bodies, optimize the density and mechanical properties of sintered bodies, and retain the good biocompatibility and bioactivity of β-TCP, thereby meeting the needs of high-standard medical applications such as bone repair and bone replacement.

Description

Technical Field

[0001] This invention relates to the field of ceramic photocuring additive manufacturing technology, and in particular to a β-tricalcium phosphate-based photocurable ceramic slurry and its preparation method. Background Technology

[0002] The statements herein provide only background information in relation to this invention and do not necessarily constitute prior art.

[0003] In recent years, photopolymerization additive manufacturing technologies such as digital light processing (DLP) and stereolithography (SLA) have developed rapidly, providing new solutions for the precision forming of high-performance ceramic materials. Particularly in the field of biomedical materials, photopolymerization forming processes based on ceramic slurries have attracted much attention due to their high precision and ability to manufacture complex structures. Among these, β-tricalcium phosphate (β-TCP), as an inorganic material with excellent bioactivity, biodegradability, and the ability to promote bone regeneration, is widely used in the preparation of artificial bone substitutes and bone tissue engineering scaffolds.

[0004] Currently, photocurable ceramic additive manufacturing typically involves mixing UV-sensitive resin monomers with ceramic powder to form a slurry, then curing it layer by layer to obtain a green body, followed by debinding and high-temperature sintering to obtain a dense ceramic part. However, for β-TCP powders, traditional photocurable ceramic slurry systems still face the following problems and challenges:

[0005] The ceramic slurry for photocuring β-tricalcium phosphate has poor rheological properties. When the slurry has a high solid content, it will result in high viscosity, which can easily cause coating difficulties or forming defects during the printing process. Therefore, its solid content is generally low. However, low solid content can easily lead to insufficient structural strength after printing, large shrinkage and severe deformation during sintering.

[0006] Furthermore, β-tricalcium phosphate-based photocured ceramic slurries exhibit poor dispersion stability and are prone to sedimentation or flocculation after prolonged standing, affecting printing accuracy and consistency. Moreover, they are susceptible to cracking and porosity during the debinding stage, have a narrow sintering temperature window, and struggle to achieve microstructural densification. Additionally, β-TCP exhibits significant brittleness, resulting in insufficient density and fracture toughness, ultimately leading to mechanical properties in the final product that fail to meet clinical application requirements and limiting its application scenarios. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide a β-tricalcium phosphate-based photocurable ceramic slurry and its preparation method. This slurry ensures high solids content, high dispersion stability, and good rheological properties while simultaneously achieving debinding, sintering, and densification. This effectively improves the mechanical stability of the green body, optimizes the density and mechanical properties of the sintered body, and retains the good biocompatibility and bioactivity of β-TCP, thereby meeting the needs of high-standard medical applications such as bone repair and bone replacement.

[0008] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0009] In a first aspect, the present invention provides a β-tricalcium phosphate-based photocurable ceramic slurry, comprising, by volume, the following components: 55-70 parts of modified ceramic powder, 30-45 parts of resin premix, and a dispersant comprising 10-20% by mass of the modified ceramic powder;

[0010] The modified ceramic powder is a ceramic powder modified with silane coupling agent γ-glycidoxypropyltrimethoxysilane (KH560) or silane coupling agent γ-methacryloyloxypropyltrimethoxysilane (KH570).

[0011] In the ceramic powder, the mass ratio of β-tricalcium phosphate, hydroxyapatite, and yttrium-stabilized zirconium oxide (3Y-TZP) is 4-10:2-6:1. The average particle size of β-tricalcium phosphate is 6-12 μm and / or 1-4 µm; the average particle size of HA particles is 1-4 µm and / or 300-500 nm; and the average particle size of 3Y-TZP particles is 300-500 nm and / or 80-120 nm.

[0012] KH560 or KH570 accounts for 15-25% of the mass of ceramic powder.

[0013] KH550 tends to settle in photocurable slurry systems, while KH560 and KH570 can form a more stable coating layer on the surface of ceramic particles, thereby reducing particle agglomeration, improving slurry dispersibility, and ensuring the uniformity and rheological properties of the slurry. Specifically, the epoxy groups retained in KH560 can undergo ring-opening reactions with carboxyl groups or photosensitive resin monomers (TMPTA, HDDA) in subsequent reactions, leading to copolymerization and curing; while the methacrylate groups in KH570 can directly undergo free radical polymerization with the photosensitive resin, jointly participating in the formation of the curing network.

[0014] In some embodiments, the mass ratio of β-tricalcium phosphate, hydroxyapatite, and yttrium-stabilized zirconium oxide is 4-7:2-5:1.

[0015] In some embodiments, the ball milling medium used in the ball milling modification of modified ceramic powder is anhydrous ethanol.

[0016] In some embodiments, the modified ceramic powder is KH560 modified ceramic powder.

[0017] Introducing fine HA and ZrO2 / 3Y-TZP particles into a slurry with coarse β-TCP particles as the matrix, using a ternary particle size distribution such as 10 μm, 2 μm, and 400 nm, allows the mass ratio of large particles to reach 70% or more, which is beneficial to improving the rheological properties of the slurry. Among them, coarse particles shrink less during sintering, which is beneficial to improving the structural support after sintering and can reduce overall shrinkage and prevent deformation and cracking; fine particles can fill the voids between particles, increase the particle packing density, and promote sintering densification.

[0018] Preferably, the average particle size of β-tricalcium phosphate is 6-12 μm; the average particle size of HA particles is 1-4 µm and / or 300-500 nm; and the average particle size of 3Y-TZP particles is 300-500 nm and / or 80-120 nm.

[0019] Further preferred, the average particle size of β-tricalcium phosphate is 6-12 μm; the average particle size of HA particles is 1-4 µm and 300-500 nm; and the average particle size of 3Y-TZP particles is 300-500 nm.

[0020] In a further preferred embodiment, the mass ratio of HA particles with an average particle size of 1-4 µm to HA particles with an average particle size of 300-500 nm is 1:0.5-2.

[0021] Preferably, β-tricalcium phosphate and HA particles are amorphous particles, while 3Y-TZP particles are spherical particles.

[0022] Spherical particles have a lower specific surface area and surface friction coefficient than irregular particles, which is beneficial to improving the fluidity of the slurry. More ceramic powder can be added at the same viscosity, thereby increasing the solid content of the slurry and the forming quality. At the same time, the smooth surface of spherical particles is not easy to agglomerate or settle, which can improve the dispersion stability; reduce light scattering and shading effects, improve the uniformity of photocuring, which is beneficial to the formation of sintering necks and grain rearrangement, and reduce printing defects.

[0023] In some embodiments, the dispersant is at least one of monolauryl ether phosphate, ammonium polyacrylate PAA-NH4, PEG400, BYK190, BYK192, AG160, AG165, AG169, silane coupling agent KH550, silane coupling agent KH560, or silane coupling agent KH570, and the dispersant accounts for 10-20% of the mass of the ceramic powder.

[0024] Preferably, the dispersant is a mixture of KH560 and PEG400, with a mass ratio of KH560 to PEG400 of 1.5-2.5:1, preferably 2:1.

[0025] The silane coupling agent KH560 has siloxane groups that can chemically bond with hydroxyl groups on the surface of ceramic particles, while the PEG400 molecular chain contains a large number of ether bonds and hydroxyl groups that can form an adsorption layer on the particle surface to prevent particle aggregation. When KH560 and PEG400 are used together as dispersants, better dispersion can be achieved.

[0026] Preferably, the dispersant is KH560.

[0027] In some embodiments, the resin premix includes a photosensitive resin monomer and a photoinitiator, wherein the photosensitive resin monomer is 1,6-hexanediol diacrylate (HDDA), polyethylene glycol diacrylate (PEGDA), trimethylolpropane triacrylate (TMPTA), or polyethylene glycol triacrylate (PEGTA).

[0028] Preferably, the resin premix contains at least one of HDDA or PEGDA, and one of TMPTA or PEGTA.

[0029] In the photosensitive resin monomer, the mass ratio of HDDA to TMPTA is 7:3 or 6:4.

[0030] Using only bifunctional monomers (such as HDDA or PEGDA) can form a linear or slightly cross-linked structure, giving the resin a certain degree of flexibility and tensile strength, but the cross-linking density is low, and the heat resistance and hardness may be insufficient. Trifunctional monomers (such as HDDA or PEGDA) can form a highly cross-linked three-dimensional network structure, which can significantly improve the hardness, heat resistance and chemical stability of the resin, but excessive cross-linking will make the resin brittle and reduce its flexibility and impact resistance.

[0031] By mixing bifunctional and trifunctional monomers, a balance can be achieved between properties such as crosslinking density, flexibility, hardness, and heat resistance.

[0032] Preferably, the photoinitiator is TPO, and the photoinitiator accounts for 3-6% of the mass of the resin monomer.

[0033] Secondly, the present invention provides a method for preparing the β-tricalcium phosphate-based photocurable ceramic slurry, comprising the following steps:

[0034] The photosensitive resin monomer and photoinitiator are mixed evenly in a certain proportion to obtain a resin premix;

[0035] After β-TCP, HA and 3Y-TZP are mixed evenly in proportion, they are ultrasonically mixed with KH560 or KH570 and anhydrous ethanol, and then ball-milled to obtain modified ceramic powder.

[0036] The resin premix, modified ceramic powder, and dispersant were mixed in proportion and ball-milled to obtain a ceramic slurry.

[0037] In some embodiments, the volume ratio of anhydrous ethanol to ceramic powder is 2-6:1, preferably 3-6:1.

[0038] In some embodiments, when preparing ceramic slurry by ball milling, the ball milling method is as follows: first forward ball milling, then reverse ball milling, with the forward ball milling time being 3-5 hours and the reverse ball milling time being 3-5 hours.

[0039] Preferably, the rotational speed during ball milling is 150-250 r·min. -1 .

[0040] Further preferably, the forward ball milling time is 4 hours, the reverse ball milling time is 4 hours, and the ratio of 6mm grinding balls to 8mm grinding balls is 1:1.

[0041] The beneficial effects achieved by one or more embodiments of the present invention described above are as follows:

[0042] In this invention, fine HA and ZrO2 / 3Y-TZP particles are introduced into a slurry with coarse β-TCP particles as the matrix. A ternary particle size distribution of 10 μm, 2 μm, and 400 nm is adopted, so that the mass ratio of large particles is 70%, which is beneficial to improving the rheological properties of the slurry. Among them, the coarse particles shrink less during sintering, which can improve the structural support after sintering and reduce overall shrinkage to prevent deformation and cracking. The fine particles can fill the voids between particles, increase the particle packing density, and promote sintering densification. Attached Figure Description

[0043] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0044] Figure 1 This is a flow chart of the slurry preparation process in Embodiment 1 of the present invention;

[0045] Figure 2 This is the multi-element high-solids, low-viscosity ceramic slurry provided in Embodiment 1 of the present invention;

[0046] Figure 3 These are the viscosity curves of the ceramic slurry at 70 vol.% and 65 vol.% for Examples 1 and 2;

[0047] Figure 4 This is a comparison chart of slurry viscosities from Examples 2, 5, and 6;

[0048] Figure 5 This is a comparison chart of slurry viscosities from Examples 6, 7, and 4;

[0049] Figure 6This is a comparison chart of slurry viscosity between Examples 2 and 8;

[0050] Figure 7 This is a viscosity comparison chart of the slurries from Examples 3 and 6;

[0051] Figure 8 This is a comparison chart of the viscosity of the slurry prepared in Example 1 under different forward and reverse ball milling times;

[0052] Figure 9 The effect of ball milling method on slurry uniformity;

[0053] Figure 10 SEM images of the green blanks and sintered parts for Examples 3 and 6;

[0054] Figure 11 The images show the XRD patterns of the modified powders from Examples 6, 7, and Comparative Example 1.

[0055] Figure 12 This is a comparison chart of the viscosity of the slurries prepared in Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3;

[0056] Figure 13 Photographs of sintered parts prepared by photopolymerization and 3D printing of the slurry used in Comparative Example 3.

[0057] Figure 14 This is a comparison graph showing the changes in energy storage modulus, loss modulus, and loss factor with shear strain for Example 1 and Comparative Example 3. Detailed Implementation

[0058] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0059] The present invention will be further described below with reference to the embodiments.

[0060] Example 1

[0061] A method for preparing a β-tricalcium phosphate-based photocurable ceramic slurry includes the following steps:

[0062] Composition: 20 wt.% KH560 modified ceramic powder, 70 vol.% resin premix, 30 vol.% dispersant KH560 (added at 15 wt.% of ceramic powder).

[0063] In the resin premix, the mass ratio of photosensitive resin HDDA:TMPTA is 6:4, and the amount of photoinitiator TPO added is 5 wt.% of the photosensitive resin monomer.

[0064] The ceramic powder includes 50 wt.% β-TCP (D 50 =10 μm) and 20 wt.% HA (D 50 =2 μm) and 20 wt.% HA (D 50 =400 nm) and 10 wt.% spherical 3Y-TZP (D 50 =400nm).

[0065] Step 1: Weigh 70gD 50 =10 μm β-TCP powder, 28 g D 50 =2 μm HA and 28 g D 50 =400 nm HA powder, 14 g D 50 =400 nm 3Y-TZP powder.

[0066] Step 2: Weigh 28 g of modifier KH560, mix the ceramic powder from Step 1 with the modifier, add 4 times the volume of anhydrous ethanol, and ball mill in a planetary ball mill at 200 r / min for 4 h. After centrifugation and cleaning, dry in a vacuum drying oven at 100 ℃ for 2 h, and pass through a 200 mesh sieve to obtain the modified powder.

[0067] Step 3: Weigh 10.91 g HDDA and 7.92 g TMPTA, and weigh 0.94 g TPO according to the 5% mass fraction of resin monomers, and mix the two together.

[0068] Step 4: Sonicate the mixture from Step 3 at 30 °C for 30 min to completely dissolve the photoinitiator in the resin monomer.

[0069] Step 5: Weigh 15 wt.% KH560 as a dispersant based on the powder mass weighed in Step 1, with a weighing amount of 21 g.

[0070] Step 6: Add the modified ceramic powder from Step 2, the resin medium obtained in Step 4, and the dispersant from Step 5 into a ball mill jar. Add 6 mm and 10 mm zirconia grinding balls to the ball mill jar in a 1:1 ratio. The ball-to-material mass ratio is 4:1. Mill the mixture in both directions at 200 r / min for 4 h each to obtain β-TCP-based ceramic slurry.

[0071] Example 2

[0072] The difference from Example 1 is that 20 wt.% KH560 modified ceramic powder accounted for 65 vol.%.

[0073] Example 3

[0074] The difference from Example 1 is that: 60 vol.% of ceramic powder modified with 15 wt.% KH560 (KH560 added at 15 wt.% of the ceramic powder mass) and 40 vol.% resin premix.

[0075] The total weight of the ceramic powder is the same as in Example 1, including 70 wt.% of β-TCP (D50=5 μm) and 30 wt.% of HA (D50=2 μm), excluding 3Y-TZP, and otherwise the same as in Example 1.

[0076] Example 4

[0077] The difference from Example 6 is that the dispersant used is PEG400+KH560, and the mass ratio of PEG400 to KH560 is 1:2.

[0078] Example 5

[0079] The difference from Example 2 is that 20 wt.% of KH560 modified ceramic powder accounts for 60 vol.%, and the ceramic powder composition is β-TCP:HA:3Y-TZP= 6:3:1.

[0080] Example 6

[0081] The difference from Example 3 is that the total weight of the ceramic powder is the same as in Example 3, and the specific composition is β-TCP:HA:3Y-TZP= 6:3:1. Everything else is the same as in Example 3.

[0082] Example 7

[0083] The difference from Example 6 is that the modifier is KH570.

[0084] Example 8

[0085] The difference from Example 2 is that the content of modifier KH560 is 15% of the mass of ceramic powder.

[0086] By comparing the slurry viscosity of Examples 1 and 2 ( Figure 3 It was found that when the solid content was >60 vol.%, a modifier content of 20 wt.% of the ceramic powder mass and a dispersant content of 15 wt.% of the ceramic powder mass could maintain the slurry viscosity at 30 s. -1 The time is less than 5 Pa·s, which meets the requirements for SLA printing.

[0087] By comparing the slurry viscosity of Examples 2, 5, and 6 (e.g., ... Figure 4 It was found that for a slurry with a solid content of 60 vol.%, the dispersion effect was better and the viscosity was lower when the modifier content was reduced from 20 wt.% to 15 wt.%.

[0088] By comparing the slurry viscosity of Examples 4, 6, and 7 (e.g. Figure 5 When KH570 was used as a modifier, it was found that it had a 30-second effect. -1 When the viscosity at the shear rate is greater than 5 Pa·s, PEG400+KH560 can still meet the viscosity requirements of slurry for SLA 3D printing. Using KH560 as a dispersant results in better dispersion.

[0089] By comparing the slurry viscosity of Examples 2 and 8 (e.g.) Figure 6 It was found that when the solid content was >65 vol.%, the rheological properties were not as good as when the modifier content was 15 wt.%.

[0090] Regarding the optimal ball milling time for the slurry: The slurry from Example 1 was selected, and its viscosity was tested at the same ball milling time in both forward and reverse directions. Figure 8 and Figure 9 Findings: The slurry viscosity was lowest when ball milling was performed for 4 hours in both directions, i.e., the total ball milling time was 8 hours.

[0091] Photopolymerization printing was performed on the slurry from Example 3. Some green bodies exhibited weak adhesion. Normal green bodies were sintered at 1250 °C. Mechanical property analysis of the sintered parts revealed a maximum flexural strength of 14 MPa. SEM image analysis of the sintered parts showed numerous pores, indicating weak adhesion after sintering of the binary particle size distribution. The density of the sintered parts was relatively low at 80%.

[0092] The ceramic slurry prepared in Example 6 was subjected to photopolymerization printing. The green body showed high printing strength and good forming. The green body was sintered at 1250 °C, and the mechanical properties of the sintered part were analyzed: its flexural strength reached 55 MPa; SEM images showed that the powder had strong adhesion and few pores after sintering; the density reached 90%. Compared with the binary particle size distribution of Example 3, the ternary particle size distribution of Example 6 not only had better rheological properties (such as... Figure 7 ), with increased density and better mechanical properties (such as Figure 10 ).

[0093] In addition, such as Figure 7 As shown, the ceramic powder in Example 3 did not contain 3Y-TZP, while the ceramic powder in Example 6 contained 3Y-TZP. The rheological properties of the slurry in Example 6 were significantly better than those in Example 3, indicating that the addition of nano-sized 3Y-TZP promoted the improvement of the slurry rheological properties.

[0094] Depend on Figure 11As can be seen from the XRD patterns of the modified powder and the standard card, the three substances undergo chemical adsorption. Specifically, the functional groups in the modifier molecule react with the active groups such as hydroxyl groups (-OH) on the powder surface through dehydration condensation to form chemical bonds, such as Si-O bonds. The modifier only reacts with surface atoms to form monomolecular or multimolecular adsorption layers and does not penetrate the interior of the powder. The ceramic powder retains its original chemical composition; that is, the positions and intensities of the diffraction peaks remain unchanged before and after modification, indicating that the crystal structure has not changed.

[0095] Comparative Example 1

[0096] The difference from Example 1 is that the modifier KH560 is replaced with monolauryl ether phosphate (AEO-3P), while everything else is the same as in Example 1.

[0097] Comparative Example 2

[0098] The difference from Example 1 is that in step 2, when modifying the ceramic powder, the added ball milling media is replaced with isopropanol instead of anhydrous ethanol; otherwise, it is the same as in Example 1.

[0099] Comparative Example 3

[0100] The difference from Example 1 is that in step 2, the method for modifying the ceramic powder is as follows: the ceramic powder is soaked in 0.5 mol / L NaOH solution for 24 h, washed and cooled, and then the ceramic powder is passed through a 100-mesh sieve. Then, the powder and 30% mass fraction H2O2 solution are added to a container at a volume ratio of 1:2. After magnetic stirring for 30 min, the container is placed in a drying oven and dried at 100°C for 6 h to obtain powder. The powder is then ground and crushed to obtain modified ceramic powder. All other steps are the same as in Example 1.

[0101] By comparing the viscosity of Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3, as shown... Figure 12 As shown.

[0102] At a shear rate of 30s -1 In Comparative Example 1, the viscosity of the slurry prepared using monolauryl ether phosphate as a modifier reached 31905 mPa·s, while in Comparative Example 2, the viscosity of the slurry prepared using isopropanol as the modifier reached 29692 mPa·s. Neither of these slurries met the viscosity required for uniform coating by the doctor blade in photopolymer 3D printing, and their rheological properties could not be measured.

[0103] The reasons for this are as follows: In Comparative Example 1, when monolauryl ether phosphate is used as a modifier, its molecular structure mainly contains phosphate groups and long-chain alkyl groups. The phosphate groups can react with some metal ions or substances containing hydroxyl groups, but its reactivity is not as good as the epoxy and siloxane structures of KH560. Furthermore, its solution viscosity is relatively high, so its effect on improving the interface bonding between inorganic and organic substances is relatively weak. In Comparative Example 2, when the modifying solvent is changed to isopropanol, the isopropanol solution itself has slightly lower polarity, and the silanol self-polymerization tendency of KH560 modifier is slightly higher when it is hydrolyzed in it. Moreover, the hydroxyl group of isopropanol is a secondary alcohol, which has greater steric hindrance than ethanol. In addition, since KH560 is sensitive to water and the degree of hydrolysis needs to be controlled, the water content of isopropanol is more difficult to control precisely. Insufficient water will affect the complete hydrolysis of silane coupling agent and affect the bonding with the surface of ceramic powder. Excessive water will cause the modifier to over-hydrolyze or agglomerate. Therefore, in Comparative Example 2, after replacing the modifier with isopropanol, the modifier was not completely hydrolyzed, resulting in poor modification effect and high viscosity of the prepared slurry.

[0104] By comparing the slurry viscosity of Example 1 and Comparative Example 3, 30 s -1 The viscosity of Comparative Example 3 at the shear rate is 4815.3 mPa·s, which meets the viscosity requirements of the doctor blade coating slurry for photopolymer 3D printing.

[0105] Subsequently, the slurries from Example 1 and Comparative Example 3 were subjected to photopolymerization 3D printing, debinding, and sintering processes. During the printing process, it was found that the slurry from Comparative Example 3 would scratch the printed green part, resulting in poor surface forming quality. After the green part was printed, it was debinded and sintered, and the resulting sintered part is as follows. Figure 13 The surface peeling phenomenon has occurred.

[0106] The surfaces of the green bodies of Example 1 and Comparative Example 3 were subjected to post-treatments such as sanding and polishing, and their mechanical properties were tested. When sintered at 1200 °C, Example 1 exhibited a flexural strength of 55.08 MPa and a fracture toughness of 2.96 MPa·m. 1 / 2 The comparative example 3, sintered at 1200 ℃, exhibited a flexural strength of 25.37 MPa and a fracture toughness of only 1.49 MPa·m. 1 / 2 .

[0107] The reasons for the failure are as follows: In Comparative Example 3, NaOH was used to etch the ceramic surface to increase roughness, and then H2O2 was used under alkaline conditions to decompose and generate hydroxyl radicals and peroxide anions, triggering an oxidation reaction on the particle surface. However, this modification method only etched the ceramic particle surface, increasing the number of hydroxyl sites. During slurry preparation, under a high solid content of 70 vol.%, the amount of free resin molecules in the ceramic powder was low. Adding dispersant KH560 at this point, due to the low liquid phase content, prevented KH560 from fully reacting with the hydroxyl groups enriched on the ceramic particle surface, leading to increased viscosity, although the viscosity still met the requirements for photopolymer 3D printing. During printing, uneven slurry coating resulted in "stringing," and the scraper damaged parts of the formed blank surface. Peeling was observed after printing, debinding, and sintering, also due to weak adhesion between layers, indicating particle agglomeration and poor dispersibility in the slurry. Consequently, the corresponding flexural strength and fracture toughness decreased.

[0108] Through analysis Figure 14 The storage modulus, loss modulus, and loss factor of Examples 1 and 3 are shown as variations with shear strain, where the loss factor is the ratio of storage modulus to loss modulus, expressed in units of 1. In Example 1, a loss factor of 1 corresponds to a shear strain of 0.17%, while in Comparative Example 3, a loss factor of 0 corresponds to a shear strain of 12.5%. A loss factor of 1 corresponds to a larger shear strain, meaning that the slurry needs to undergo significant deformation to reach a state of elastic and viscous equilibrium. This indicates that Comparative Example 3 has a higher degree of molecular entanglement, requiring a larger strain to untangle and generate viscous flow under shear stress. The reason for this is that KH560 needs to be hydrolyzed in an alcohol system to produce silanol. The silanol then chemically bonds with the hydroxyl groups abundant on the ceramic surface to form a siloxane monolayer coating the ceramic particle surface. In Comparative Example 3, when NaOH etching was used, H2O2 dissolved on the surface of ceramic particles to form more hydroxyl groups. Then, KH560 was mixed with resin premix and modified ceramic powder by ball milling. At this time, the liquid phase accounted for a small proportion in the 70 vol.% solid content slurry. The dispersant KH560 could not be completely bonded to the hydroxyl groups on the surface of the hydroxylated ceramic powder. This resulted in some self-entanglement of KH560 molecules and the unbonded hydroxyl groups on the surface of ceramic particles still having hydrophilic and oleophobic properties. Therefore, the particles in the slurry were unevenly dispersed and had poor dispersibility, which affected the subsequent photopolymerization printing.

[0109] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A beta-tricalcium phosphate based light solidification formed ceramic slurry, characterized by: The ceramic slurry comprises, by volume fraction, 55-70 parts of modified ceramic powder, 30-45 parts of resin premix, and 10-20% of dispersant based on the mass of the modified ceramic powder; The modified ceramic powder is KH560-modified ceramic powder, and the ball milling medium for ball milling modification of the modified ceramic powder is anhydrous ethanol. The mass ratio of β-tricalcium phosphate, hydroxyapatite, and yttrium-stabilized zirconia is 4-10:2-6:1, the average particle size of the β-tricalcium phosphate is 6-12 μm, the average particle size of the HA particles is 1-4 μm and 300-500 nm, and the average particle size of the 3Y-TZP particles is 300-500 nm; in the HA particles, the mass ratio of the HA particles with an average particle size of 1-4 μm to the HA particles with an average particle size of 300-500 nm is 1:0.5-2. The mass percentage of KH560 in the ceramic powder is 15-25%.

2. The beta-tricalcium phosphate-based light-cured shaping ceramic slurry according to claim 1, characterized in that: The mass ratio of β-tricalcium phosphate, hydroxyapatite, and yttrium-stabilized zirconia is 4-7:2-5:

1.

3. The beta-tricalcium phosphate-based light-cured shaping ceramic slurry according to claim 1, characterized in that: The β-tricalcium phosphate and HA particles are amorphous particles, and the 3Y-TZP particles are spherical particles.

4. The beta-tricalcium phosphate-based light-cured shaped ceramic slurry of claim 1, wherein: The dispersant is at least one of monolauryl alcohol ether phosphate, ammonium polyacrylate PAA-NH4, PEG400, BYK190, BYK192, AG160, AG165, AG169, silane coupling agent KH550, silane coupling agent KH560, or silane coupling agent KH570, and the mass percentage of the dispersant in the ceramic powder is 10-20%.

5. The beta-tricalcium phosphate-based light-cured shaped ceramic slurry according to claim 4, characterized in that: The dispersant is a mixture of KH560 and PEG400, and the mass ratio of KH560 to PEG400 is 1.5-2.5:

1.

6. The beta-tricalcium phosphate-based light-cured shaped ceramic slurry according to claim 5, characterized in that: The mass ratio of KH560 to PEG400 is 2:

1.

7. The beta-tricalcium phosphate-based light-cured shaped ceramic slurry of claim 1, wherein: The resin premix comprises photosensitive resin monomers and a photoinitiator, and the photosensitive resin monomers are 1,6-hexanediol diacrylate, polyethylene glycol diacrylate, or trimethylolpropane triacrylate.

8. The beta-tricalcium phosphate-based light-cured shaped ceramic slurry according to claim 7, characterized in that: The photoinitiator is TPO, and the mass percentage of the photoinitiator in the resin monomers is 3-6%.

9. The method of producing a β-tricalcium phosphate-based photocurable forming ceramic slurry according to any one of claims 1 to 8, characterized by: The method comprises the following steps: The photosensitive resin monomers and the photoinitiator are uniformly mixed in a certain proportion to obtain the resin premix; The β-TCP, HA, and 3Y-TZP are uniformly mixed in a certain proportion, and then ultrasonically mixed with KH560 and anhydrous ethanol to obtain the modified ceramic powder; The resin premix, the modified ceramic powder, and the dispersant are mixed in a certain proportion and ball milled to obtain the ceramic slurry.

10. The method for preparing the β-tricalcium phosphate-based photocurable ceramic slurry according to claim 9, characterized in that: The volume ratio of anhydrous ethanol to ceramic powder is 2-6:

1.

11. The method for preparing the β-tricalcium phosphate-based photocurable ceramic slurry according to claim 10, characterized in that: The volume ratio of anhydrous ethanol to ceramic powder is 3-6:

1.

12. The method for preparing the β-tricalcium phosphate-based photocurable ceramic slurry according to claim 9, characterized in that: In the ball milling process for preparing the ceramic slurry, the ball milling is performed in a forward direction first and then in a reverse direction, the time for forward direction ball milling is 3-5 h, and the time for reverse direction ball milling is 3-5 h. The rotation speed during the ball milling is 150-250 r·min -1 ; The number ratio of 6 mm ball milling balls to 8 mm ball milling balls is 1:

1.

13. The method for preparing the β-tricalcium phosphate-based photocurable ceramic slurry according to claim 12, characterized in that: The time for forward direction ball milling is 4 h, and the time for reverse direction ball milling is 4 h.

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