Beta-tricalcium phosphate-based photocuring formed ceramic slurry and preparation method thereof

Abstract

The invention discloses beta-tricalcium phosphate-based photocuring formed ceramic slurry and a preparation method thereof, and the beta-tricalcium phosphate-based photocuring formed ceramic slurry comprises the following components in parts by volume: 66-75 parts of modified ceramic powder, 25-30 parts of a resin premixed solution, and a dispersant accounting for 10-20% of the mass fraction of the modified ceramic powder, the modified ceramic powder is a KH560 or KH570 modified ceramic powder body; the mass ratio of the beta-tricalcium phosphate to the hydroxyapatite to the 3Y-TZP is (4-10): (2-6): 1, and the average particle size of the beta-tricalcium phosphate is 6-12 [mu] m and / or 1-4 m; the average particle size of the HA particles is 1-4 m and / or 300-500 nm; the average particle size of the 3Y-TZP particles is 300 to 500 nm and / or 80 to 120 nm. The high solid content, the high dispersion stability and the good rheological property are guaranteed, meanwhile, degreasing sintering densification is considered, the mechanical stability of a green body is effectively improved, the density and the mechanical property of a sintered body are optimized, meanwhile, the good biocompatibility and the biological activity of beta-TCP are reserved, and therefore the requirements of high-standard medical application such as bone repair and bone replacement are met.

Description

Technical Field

[0001] The present invention relates to the technical field of ceramic light-curing additive manufacturing, and in particular to a β-tricalcium phosphate-based light-curing formed ceramic slurry and a preparation method thereof. Background Art

[0002] The statements herein merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] In recent years, photocurable additive manufacturing technologies such as digital light processing (DLP) and stereolithography (SLA) have rapidly developed, providing new solutions for the precision forming of high-performance ceramic materials. In the field of biomedical materials, photocurable forming processes based on ceramic slurries have attracted considerable attention due to their high-precision and complex structure fabrication capabilities. β-tricalcium phosphate (β-TCP), 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 a UV-sensitive resin monomer with ceramic powder to form a slurry, which is then cured layer by layer to produce a green body. This is then followed by degreasing and high-temperature sintering to create a dense ceramic part. However, for β-TCP powder, traditional photocurable ceramic slurry systems still face the following problems and challenges: The rheological properties of β-tricalcium phosphate-based photocuring ceramic slurry are poor. When the solid content of the slurry is high, the viscosity is high, which can easily cause coating difficulties or forming defects during the printing process. Therefore, the solid content of the slurry is generally low. However, low solid content can easily lead to insufficient structural strength after printing, large shrinkage during sintering, and severe deformation.

[0005] Furthermore, the dispersion stability of β-tricalcium phosphate-based photocurable ceramic slurries is poor. Prolonged standing can lead to sedimentation or flocculation, affecting printing accuracy and consistency. Furthermore, cracks and holes are prone to form during the degreasing phase, and the sintering temperature window is narrow, making densification difficult. Furthermore, the brittleness of β-TCP, coupled with insufficient density and fracture toughness, makes the mechanical properties of the final product difficult to meet clinical application requirements, limiting its application scenarios. Summary of the Invention

[0006] 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. While ensuring high solids content, high dispersion stability, and good rheological properties, this slurry also allows for degreasing and sintering densification, effectively improving the mechanical stability of the green body and optimizing the density and mechanical properties of the sintered body. This slurry also retains the excellent biocompatibility and bioactivity of β-TCP, thus meeting the needs of high-standard medical applications such as bone repair and bone replacement.

[0007] In order to achieve the above object, the present invention is implemented through the following technical solutions: In a first aspect, the present invention provides a β-tricalcium phosphate-based photocurable ceramic slurry, comprising the following components, by volume: 55-70 parts of modified ceramic powder, 30-45 parts of a resin premix, and a dispersant accounting for 10-20% by mass of the modified ceramic powder; The modified ceramic powder is a ceramic powder modified by a silane coupling agent γ-glycidyloxypropyltrimethoxysilane (KH560) or a silane coupling agent γ-methacryloxypropyltrimethoxysilane (KH570); In the ceramic powder, the mass ratio of β-tricalcium phosphate, hydroxyapatite and yttrium-stabilized zirconia (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. The mass percentage of KH560 or KH570 in the ceramic powder is 15-25%.

[0008] While KH550 is prone to sedimentation in photocurable slurry systems, KH560 and KH570 form a more stable coating on the ceramic particle surface, reducing interparticle agglomeration, improving slurry dispersion, and ensuring slurry uniformity and rheological properties. The retained epoxy groups of KH560 can subsequently react with carboxyl groups or photosensitive resin monomers (TMPTA, HDDA) through ring-opening reactions, resulting in copolymerization and curing. The methacrylate groups of KH570 can directly undergo free radical polymerization with the photosensitive resin, contributing to the formation of a curing network.

[0009] In some embodiments, the mass ratio of β-tricalcium phosphate, hydroxyapatite, and yttrium-stabilized zirconia is 4-7:2-5:1.

[0010] In some embodiments, the ball milling medium used in ball milling of the modified ceramic powder is anhydrous ethanol.

[0011] In some embodiments, the modified ceramic powder is KH560 modified ceramic powder.

[0012] Fine HA and ZrO2 / 3Y-TZP particles are introduced into a slurry based on coarse β-TCP particles, and a ternary particle size distribution of 10 μm, 2 μm, and 400 nm is adopted, so that the mass proportion of large particles can reach 70% or more, which is beneficial to improving the rheological properties of the slurry. Among them, the coarse particles shrink less during sintering, which is beneficial to improving the structural support force after sintering, reducing overall shrinkage and preventing deformation and cracking; fine particles can fill the gaps between particles, increase the particle packing density, and promote sintering densification.

[0013] 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.

[0014] More 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 300-500 nm; and the average particle size of 3Y-TZP particles is 300-500 nm.

[0015] Still further preferably, in the HA particles, 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.

[0016] Preferably, the β-tricalcium phosphate and HA particles are amorphous particles, and the 3Y-TZP particles are spherical particles.

[0017] 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 surface of spherical particles is smooth and not easy to agglomerate or settle, which can improve the dispersion stability; reduce light scattering and shielding effects, improve the uniformity of light curing, facilitate the formation of sintering necks and grain rearrangement, and reduce printing defects.

[0018] In some embodiments, the dispersant is at least one of monolauryl ether phosphate, polyacrylate ammonium 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.

[0019] Preferably, the dispersant is a mixture of KH560 and PEG400, and the mass ratio of KH560 to PEG400 is 1.5-2.5:1, preferably 2:1.

[0020] The siloxy groups in the silane coupling agent KH560 molecules can chemically bond with the 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 agglomeration; when KH560 and PEG400 are used together as dispersants, better dispersion effects can be achieved.

[0021] Preferably, the dispersant is KH560.

[0022] In some embodiments, the resin premix includes a photosensitive resin monomer and a photoinitiator, and the photosensitive resin monomer is 1,6-hexanediol diacrylate (HDDA), polyethylene glycol diacrylate (PEGDA), trimethylolpropane triacrylate (TMPTA) or polyethylene glycol triacrylate (PEGTA).

[0023] Preferably, the resin premix includes at least one of HDDA or PEGDA, and one of TMPTA or PEGTA.

[0024] In the photosensitive resin monomer, the mass ratio of HDDA to TMPTA is 7:3 or 6:4.

[0025] Using only bifunctional monomers (such as HDDA or PEGDA) can form a linear or lightly 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 greatly improve the hardness, heat resistance and chemical stability of the resin, but excessive cross-linking will make the resin brittle and reduce flexibility and impact resistance.

[0026] Mixing difunctional monomers and trifunctional monomers can achieve a balance between properties such as crosslinking density, flexibility, hardness, and heat resistance.

[0027] Preferably, the photoinitiator is TPO, and the photoinitiator accounts for 3-6% of the mass of the resin monomer.

[0028] In a second aspect, the present invention provides a method for preparing the β-tricalcium phosphate-based photocurable ceramic slurry, comprising the following steps: Mixing the photosensitive resin monomer and the photoinitiator in proportion to obtain a resin premix solution; β-TCP, HA and 3Y-TZP were mixed uniformly in proportion, and then ultrasonically mixed with KH560 or KH570 and anhydrous ethanol, and then ball milled to obtain modified ceramic powder. The resin premix liquid, modified ceramic powder and dispersant are mixed in proportion and ball-milled to obtain ceramic slurry.

[0029] In some embodiments, the volume ratio of anhydrous ethanol to ceramic powder is 2-6:1, preferably 3-6:1.

[0030] In some embodiments, when preparing the ceramic slurry by ball milling, the ball milling method is: first forward ball milling, then reverse ball milling, the forward ball milling time is 3-5 hours, and the reverse ball milling time is 3-5 hours.

[0031] Preferably, the rotation speed during ball milling is 150-250 r·min -1 .

[0032] Further preferably, the forward ball milling time is 4 hours, the reverse ball milling time is 4 hours, and the ratio of 6 mm ball milling balls to 8 mm ball milling balls is 1:1.

[0033] The beneficial effects achieved by one or more embodiments of the present invention are as follows: In the present invention, fine HA and ZrO2 / 3Y-TZP particles are introduced into a slurry based on coarse β-TCP particles, and a ternary particle size distribution of 10 μm, 2 μm, and 400 nm is adopted, so that the mass proportion 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 and are used to improve the structural support force after sintering, which can reduce overall shrinkage and prevent deformation and cracking; the fine particles can fill the gaps between the particles, increase the particle packing density, and promote sintering densification. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0035] Figure 1 is a flow chart of the slurry preparation process of Example 1 of the present invention; Figure 2 The multi-component high-solid low-viscosity ceramic slurry provided in Example 1 of the present invention; Figure 3 70 vol.% and 65 vol.% ceramic slurry viscosity curves of Example 1 and Example 2; Figure 4 is a comparison chart of the slurry viscosities of Example 2, Example 5, and Example 6; Figure 5 is a comparison chart of the slurry viscosities of Example 6, Example 7, and Example 4; Figure 6 is a comparison chart of the slurry viscosities of Example 2 and Example 8; Figure 7 3 is a comparison chart of the viscosity of the slurries of Example 3 and Example 6; Figure 8 1 is a comparison chart of the viscosity of the slurry prepared in Example 1 at different forward and reverse ball milling times; Figure 9 The effect of ball milling method on slurry uniformity; Figure 10 The green body images and sintered parts SEM images of Example 3 and Example 6; Figure 11 The XRD patterns of the modified powders of Example 6, Example 7 and Comparative Example 1 are shown; Figure 121 is a comparison chart of the viscosities of the slurries prepared in Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3; Figure 13 This is a photo of a sintered part prepared by sintering the slurry prepared in Comparative Example 3 after photocuring 3D printing; Figure 14 The figure is a comparison of the storage modulus, loss modulus and loss factor of Example 1 and Comparative Example 3 as a function of shear strain. DETAILED DESCRIPTION

[0036] It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those skilled in the art to which the present invention belongs.

[0037] The present invention will be further described below with reference to the embodiments.

[0038] Example 1 A method for preparing a β-tricalcium phosphate-based photocurable ceramic slurry comprises the following steps: Ingredients: 20 wt.% KH560 modified ceramic powder 70 vol.%, resin premix 30 vol.% and dispersant KH560 (added amount is 15 wt.% of ceramic powder).

[0039] 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; The ceramic powder includes 50 wt.% of 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).

[0040] Step 1: Weigh 70g of D 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.

[0041] Step 2: Weigh 28 g of modifier KH560, mix the ceramic powder in 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 centrifugal cleaning, dry it in a vacuum drying oven at 100 °C for 2 h, and pass it through a 200-mesh sieve to obtain the modified powder.

[0042] Step 3: Weigh 10.91 g HDDA and 7.92 g TMPTA, and weigh 0.94 g TPO based on a 5% mass fraction of the resin monomer, and mix the two.

[0043] Step 4: Ultrasonic oscillate the mixture in step 3 at 30°C for 30 min to completely dissolve the photoinitiator in the resin monomer.

[0044] Step 5: Based on the mass of the powder weighed in step 1, weigh 15 wt.% KH560 as a dispersant, the amount is 21 g.

[0045] Step 6: Add the modified ceramic powder in step 2, the resin medium obtained in step 4, and the dispersant in step 5 into a ball mill, add 6 mm and 10 mm zirconia ball milling balls in a 1:1 ratio into the ball mill, and the ball-to-material mass ratio is 4:1. Mill the ball at a speed of 200 r / min for 4 h in both forward and reverse directions to obtain a β-TCP-based ceramic slurry.

[0046] Example 2 The difference from Example 1 is that the 20 wt.% KH560 modified ceramic powder accounts for 65 vol.%.

[0047] Example 3 The difference from Example 1 is that: 60 vol.% of ceramic powder modified with 15 wt.% KH560 (the amount of KH560 added is 15 wt.% of the mass of the ceramic powder), and 40 vol.% of the resin premix.

[0048] The total weight of the ceramic powder is the same as that in Example 1, including 70 wt.% of β-TCP (D50=5 μm) and 30 wt.% of HA (D50=2 μm), excluding 3Y-TZP, and the rest is the same as that in Example 1.

[0049] Example 4 The difference from Example 6 is that the dispersant used is PEG400+KH560, and the mass ratio of PEG400 to KH560 is 1:2.

[0050] Example 5 The difference from Example 2 is that: 20 wt.% KH560 modified ceramic powder accounts for 60 vol.%, and the ceramic powder composition is β-TCP:HA:3Y-TZP=6:3:1.

[0051] Example 6 The difference from Example 3 is that the total weight of the ceramic powder is the same as that of Example 3, the specific composition is β-TCP:HA:3Y-TZP=6:3:1, and the other aspects are the same as those of Example 3.

[0052] Example 7 The difference from Example 6 is that the modifier is KH570.

[0053] Example 8 The difference from Example 2 is that the content of the modifier KH560 is 15% of the mass of the ceramic powder.

[0054] By comparing the slurry viscosity of Example 1 and Example 2 ( Figure 3 ), it was found that when the solid content was >60 vol.%, the modifier was 20 wt.% of the ceramic powder mass, and the dispersant was 15 wt.% of the ceramic powder mass, the slurry viscosity could be kept at 30s -1 The pressure is less than 5Pa·s, which meets the SLA printing requirements.

[0055] By comparing the slurry viscosities of Example 2, Example 5 and Example 6 ( 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.%.

[0056] By comparing the slurry viscosity of Example 4, Example 6 and Example 7 (as shown in FIG Figure 5 ), it was found that when KH570 was used as a modifier, it -1 The viscosity under shear rate is greater than 5 Pa·s. When PEG400+KH560 is used as a dispersant, the slurry viscosity requirements for SLA 3D printing can also be met. The dispersion effect is better when KH560 is used as a dispersant.

[0057] By comparing the slurry viscosity of Example 2 and Example 8 (such as Figure 6 ), it was found that when the solid content was >65 vol.%, the rheological properties of the modifier at 15 wt.% were not as good as those at 20 wt.%.

[0058] For the best time of slurry milling: the slurry of Example 1 was selected and its viscosity was tested when the forward and reverse milling times were the same. Figure 8 and Figure 9It was found that the slurry viscosity was lowest when the forward and reverse ball milling were 4 hours each, that is, the total ball milling time was 8 hours.

[0059] When the slurry from Example 3 was subjected to stereolithography printing, some green parts exhibited weak adhesion. Mechanical property analysis of the normal green parts, sintered at 1250°C, revealed a maximum flexural strength of 14 MPa. SEM analysis of the sintered parts revealed numerous pores, indicating weak adhesion after sintering the binary particle size. The resulting sintered parts had a relatively low density of 80%.

[0060] The ceramic slurry prepared in Example 6 was subjected to photocuring printing. The green body printing strength was high and the forming was good. The green body was sintered at 1250 ° C, and the mechanical properties of the sintered part were analyzed: its flexural strength can reach 55 MPa; the SEM spectrum shows that the powder has strong cohesion and less pores after sintering; the density reaches 90%. Compared with the binary particle size grading of Example 3, the ternary particle size grading of Example 6 not only has better rheological properties (such as Figure 7 ), the density is enhanced and the mechanical properties are also good (such as Figure 10 ).

[0061] In addition, if Figure 7 As shown, the ceramic powder in Example 3 does not contain 3Y-TZP, while the ceramic powder in Example 6 contains 3Y-TZP. The rheological properties of the slurry in Example 6 are significantly better than those of the slurry in Example 3, indicating that the addition of nano-scale 3Y-TZP promotes the improvement of the rheological properties of the slurry.

[0062] Depend on Figure 11 Comparison of the XRD patterns of the modified powder with those of the standard card reveals that the three react through chemical adsorption, whereby the functional groups in the modifier molecules react with reactive groups such as hydroxyl groups (-OH) on the powder surface through dehydration condensation to form chemical bonds, such as Si-O bonds. The modifier reacts only with surface atoms, forming a monomolecular or multimolecular adsorption layer that does not penetrate the interior of the powder. The ceramic powder retains its original chemical composition, indicating that the diffraction peak positions and intensities remain unchanged before and after modification, indicating that the crystal structure remains unchanged.

[0063] Comparative Example 1 The difference from Example 1 is that the modifier KH560 is replaced by monolauryl ether phosphate (AEO-3P), and the rest is the same as Example 1.

[0064] Comparative Example 2 The difference from Example 1 is that in step 2, when modifying the ceramic powder, the added ball milling medium replaces anhydrous ethanol with isopropanol, and the rest is the same as Example 1.

[0065] Comparative Example 3 The difference from Example 1 is that in step 2, the method for modifying the ceramic powder is: soaking the ceramic powder in a 0.5 mol / L NaOH solution for 24 hours, washing and cooling, passing the ceramic powder through a 100-mesh sieve, and then adding the powder and a 30% mass fraction H2O2 solution to a container in a volume ratio of 1:2, stirring magnetically for 30 minutes, and then placing it in a drying oven, drying it at 100°C for 6 hours to obtain a powder, grinding and crushing it to obtain modified ceramic powder. The rest is the same as Example 1.

[0066] By comparing the viscosity of Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3, as shown in FIG. Figure 12 shown.

[0067] At a shear rate of 30 s -1 When monolauryl ether phosphate was used as the modifier in Comparative Example 1, the viscosity of the slurry prepared reached 31905 mPa·s. When isopropyl alcohol was used as the modifying solvent in Comparative Example 2, the viscosity of the slurry prepared reached 29692 mPa·s. Both slurries did not meet the viscosity required for uniform coating by the photocuring 3D printing scraper and their rheological properties could not be measured.

[0068] The reasons are analyzed as follows: when monolauryl ether phosphate is used as a modifier in Comparative Example 1, its molecular structure mainly contains phosphate groups and long-chain alkyl groups. The phosphate group 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. Moreover, its solution viscosity is relatively high, so its effect in improving the interfacial bonding between inorganic and organic substances is relatively weak. In Comparative Example 2, after the modification solvent was changed to isopropanol, due to the slightly lower polarity of the isopropanol solution itself, the KH560 modifier had a slightly higher tendency to self-aggregate silanols when hydrolyzed in it. In addition, the hydroxyl groups in isopropanol are secondary alcohols, and the steric hindrance is greater than that of ethanol. In addition, since KH560 is sensitive to moisture and the degree of hydrolysis needs to be controlled, the water content of isopropanol is more difficult to accurately control. Insufficient moisture will affect the complete hydrolysis of the silane coupling agent and affect the bonding with the ceramic powder surface. Excessive moisture will cause excessive hydrolysis or agglomeration of the modifier. Therefore, after replacing with isopropyl alcohol in Comparative Example 2, the modifier was not completely hydrolyzed, the modification effect was poor, and the viscosity of the prepared slurry was high.

[0069] By comparing the viscosity of the slurry in Example 1 and Comparative Example 3, the viscosity of the slurry in 30 s -1 The viscosity of Comparative Example 3 under the shear rate is 4815.3 mPa·s, which can meet the viscosity requirements of the photocurable 3D printing scraper coating slurry.

[0070] Then, the slurries of Example 1 and Comparative Example 3 were subjected to light-cured 3D printing, degreasing and sintering processes. During the printing process, it was found that the slurry of Comparative Example 3 would scratch the printed green body, resulting in poor surface forming quality of the green body. After the green body was printed, it was degreased and sintered, and the sintered parts obtained were as follows. Figure 13 Surface peeling occurred.

[0071] The surfaces of the green bodies of Example 1 and Comparative Example 3 were subjected to post-processing such as sandpaper grinding and polishing, and their mechanical properties were tested. When sintered at 1200°C, the bending strength of Example 1 was 55.08 MPa, and the fracture toughness reached 2.96 MPa·m 1 / 2 , while the bending strength of comparative example 3 when sintered at 1200 ℃ is 25.37 MPa and the fracture toughness is only 1.49 Mpa·m 1 / 2 .

[0072] The reasons for this are as follows: In Comparative Example 3, NaOH was used to etch the ceramic surface to increase roughness, and then H2O2 was used to decompose it under alkaline conditions to produce hydroxyl radicals and peroxide anions, initiating surface oxidation reactions. However, this modification method only etches the surface of the ceramic particles, increasing the number of hydroxyl sites. Furthermore, during the slurry preparation process, at a high solids content of 70 vol.%, the content of free resin molecules in the ceramic powder is relatively low. At this time, the addition of the dispersant KH560, due to the low proportion of liquid phase, prevents KH560 from fully reacting with the hydroxyl groups enriched on the surface of the ceramic particles, resulting in an increase in viscosity. However, its viscosity still meets the requirements of light-curing 3D printing. During the printing process, the slurry is unevenly applied, resulting in "stringing" phenomenon. The scraper will scrape part of the surface of the formed body. After printing, degreasing and sintering, peeling is observed. This is also due to weak adhesion between the layers, that is, the particles in the slurry are agglomerated and have poor dispersion. Therefore, the corresponding flexural strength, fracture toughness, etc. are correspondingly reduced.

[0073] Through analysis Figure 14, the storage modulus, loss modulus and loss factor of Example 1 and Comparative Example 3 vary with shear strain, where the loss factor refers to the value of storage modulus / loss modulus, with a unit of 1. In Example 1, the corresponding shear strain is 0.17% when the loss factor is 1, while the corresponding shear strain is 12.5% when the loss factor is 0 in Comparative Example 3. When the loss factor is 1, the corresponding larger shear strain means that the slurry can only reach a state of elasticity and viscosity balance when a larger deformation occurs, that is, the degree of entanglement between molecules in Comparative Example 3 is higher. When subjected to shear, a larger strain is required to disentangle the entanglement and produce viscous flow. Analyzing the reasons, KH560 needs to be hydrolyzed in an alcohol system to produce silanols, which are chemically bonded to the hydroxyl groups rich in the ceramic surface to form a siloxane monolayer coated on the surface of the ceramic particles. In Comparative Example 3, NaOH etching was used, and H2O2 dissolved on the surface of the ceramic particles to form more hydroxyl groups. KH560 was then mixed with the resin premix and the modified ceramic powder by ball milling. At this time, the liquid phase accounted for a small proportion in the 70 vol.% solid phase content slurry, and the dispersant KH560 was unable to completely bond with the hydroxyl groups on the surface of the hydroxylated ceramic powder. As a result, the KH560 molecules were partially self-entangled, and the unbonded hydroxyl groups on the surface of the ceramic particles still had hydrophilic and oleophobic properties. As a result, the particles in the slurry were unevenly dispersed and the dispersion was poor, thereby affecting subsequent photocuring printing.

[0074] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A β-tricalcium phosphate-based light-curing ceramic slurry, characterized by: The composition comprises the following components by volume: 55-70 parts of modified ceramic powder, 30-45 parts of resin premix, and the mass fraction of the dispersant in the modified ceramic powder is 10-20%; The modified ceramic powder is a ceramic powder modified by KH560 or KH570; The mass ratio of β-tricalcium phosphate, hydroxyapatite and yttrium-stabilized zirconia 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. The mass percentage of KH560 or KH570 in the ceramic powder is 15-25%.

2. The β-tricalcium phosphate-based photocurable 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; Preferably, the ball milling medium for the modified ceramic powder during ball milling is anhydrous ethanol.

3. The β-tricalcium phosphate-based photocurable ceramic slurry according to claim 1, characterized in that: The modified ceramic powder is KH560 modified ceramic powder; 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; the average particle size of 3Y-TZP particles is 300-500 nm and / or 80-120 nm; 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 300-500 nm; the average particle size of 3Y-TZP particles is 300-500 nm; Preferably, in the HA particles, 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; Preferably, the β-tricalcium phosphate and HA particles are amorphous particles, and the 3Y-TZP particles are spherical particles.

4. The β-tricalcium phosphate-based photocurable ceramic slurry according to claim 1, characterized in that: The dispersant is at least one of monolauryl ether phosphate, polyacrylate ammonium 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 ceramic powder mass; Preferably, the dispersant is a mixture of KH560 and PEG400, and the mass ratio of KH560 to PEG400 is 1.5-2.5:1, preferably 2:1; Preferably, the dispersant is KH560.

5. The β-tricalcium phosphate-based photocurable ceramic slurry according to claim 1, characterized in that: The resin premix liquid comprises a photosensitive resin monomer and a photoinitiator, wherein the photosensitive resin monomer is 1,6-hexanediol diacrylate, polyethylene glycol diacrylate, trimethylolpropane triacrylate or polyethylene glycol triacrylate.

6. The β-tricalcium phosphate-based photocurable ceramic slurry according to claim 5, characterized in that: The resin premix includes at least one of HDDA or PEGDA, and one of TMPTA or PEGTA.

7. The β-tricalcium phosphate-based photocurable ceramic slurry according to claim 5, characterized in that: The photoinitiator is TPO, and the photoinitiator accounts for 3-6% of the mass of the resin monomer.

8. The method for preparing the β-tricalcium phosphate-based photocurable ceramic slurry according to any one of claims 1 to 7, characterized in that: The steps include: Mixing the photosensitive resin monomer and the photoinitiator in proportion to obtain a resin premix solution; β-TCP, HA and 3Y-TZP were mixed uniformly in proportion, and then ultrasonically mixed with KH560 or KH570 and anhydrous ethanol, and then ball milled to obtain modified ceramic powder. The resin premix liquid, modified ceramic powder and dispersant are mixed in proportion and ball-milled to obtain ceramic slurry.

9. The method for preparing the β-tricalcium phosphate-based photocurable ceramic slurry according to claim 8, characterized in that: The volume ratio of anhydrous ethanol to ceramic powder is 2-6:1, preferably 3-6:

1.

10. The method for preparing the β-tricalcium phosphate-based photocurable ceramic slurry according to claim 8, characterized in that: When preparing ceramic slurry by ball milling, the ball milling method is: first forward ball milling, then reverse ball milling, the forward ball milling time is 3-5 hours, and the reverse ball milling time is 3-5 hours; Preferably, the rotation speed during ball milling is 150-250 r·min -1 ; Preferably, the forward ball milling time is 4 hours, the reverse ball milling time is 4 hours, and the ratio of 6 mm ball milling balls to 8 mm ball milling balls is 1:1.

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