Preparation method of photocuring slurry

Abstract

The invention provides a preparation method of light-cured slurry and belongs to the technical field of inorganic materials.According to the preparation method of the light-cured slurry, the surface of inorganic powder is coated with aluminum oxide (inorganic material) and an amine modifier (organic material), so that agglomeration among particles of the inorganic powder is reduced; the dispersion of the inorganic powder in the slurry is improved, the viscosity of the slurry is reduced, the photosensitive characteristic of an inorganic material is improved, the refractive index difference between inorganic powder particles and photosensitive resin is reduced, and the absorption and scattering of the inorganic powder to ultraviolet light are reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of inorganic materials, and more specifically, relates to a preparation method of a photocurable slurry. Background Art

[0002] The photocurable 3D printing technology is a rapid prototyping technology based on photoinitiated polymerization reaction, which has the advantages of fast forming speed and high precision. However, traditional photocurable 3D printing materials such as polymer resins have certain limitations, such as insufficient mechanical properties and poor heat resistance. Therefore, it is of great significance to apply inorganic materials such as ceramics with excellent mechanical properties, heat resistance, wear resistance and high temperature resistance to photocurable 3D printing.

[0003] With the development of the photocurable 3D printing technology, photocurable forming solutions containing inorganic materials such as ceramics, metals, metal oxides, alloys, etc. have received more and more attention from scientific researchers. However, the curing depth problem of photocurable 3D printing of inorganic materials such as zirconia, silicon carbide, silicon nitride, aluminum, chromium oxide, carbon black, titanium dioxide, cemented carbide, etc. has hindered the development of photocurable forming of inorganic materials. Due to factors such as the refractive index difference between inorganic material powders and photosensitive resins, the absorption, reflection and scattering of ultraviolet light by the powder surface, the agglomeration between powder particles, the poor wettability between the powder / photosensitive resin, the low dispersibility of the powder in the slurry and the high slurry viscosity, resulting in the problems of low curing depth and difficult forming in photocurable 3D printing of inorganic materials, the surface modification treatment of inorganic material powders is an effective and important solution method. At present, in the photocurable 3D printing of inorganic materials, only some ceramic materials have achieved commercial development, and the photocurable 3D printing of functional inorganic materials such as metals, semiconductors, metal oxides, alloys, etc. is still in the initial stage of development, and the research results are relatively few. Therefore, for the photocurable 3D printing of inorganic materials, exploring the material properties of inorganic materials in photocurable 3D printing, expanding the composition range of inorganic materials suitable for photocurable 3D printing, researching new slurries of photosensitive resin surface-modified inorganic powders, and cooperating with low-power, high-performance and high-quality photocurable 3D printing technology to realize the production of complex components with excellent comprehensive performance will be the future key research directions and have great application development potential. Summary of the Invention

[0004] Aiming at the above defects or improvement requirements of the prior art, the present invention provides a preparation method of a photocurable slurry, which combines organic coating and inorganic modification to solve the problem of large ultraviolet light refractive index difference between photocurable forming inorganic powders and photosensitive resins.

[0005] To achieve the above object, the technical solution adopted by the present invention is: to provide a preparation method of a photocurable slurry, including the following steps: S01: Add inorganic powder and aluminate into ionic water respectively and perform ultrasonic oscillation to obtain a suspension of inorganic powder; S02: Transfer the suspension to a water bath heating pan; S03: Add an alkaline precipitant into the water bath heating pan to control the pH value of the suspension within the range of 9 - 11, and stir simultaneously. Aluminum oxide precipitate will coat on the surface of the inorganic powder; S04: Filter or centrifuge the mixed solution in step S03 to separate the inorganic powder coated with aluminum oxide from the solution, and then obtain the aluminum oxide coated powder through drying, calcination and grinding; S05: Add an amine modifier and the aluminum oxide coated powder into absolute ethanol, perform water bath heating and stir. The amine modifier will coat on the surface of the aluminum oxide coated powder; S06: Heat and dry the mixed solution in step S05 to remove absolute ethanol, and then obtain the modified powder coated with amine modifier and aluminum oxide through centrifugation and drying; S07: Perform water bath heating and stir the prepolymer, monomer and photoinitiator to obtain a photosensitive resin; S08: Mix and stir the modified powder, photosensitive resin and auxiliary reagents to finally obtain a slurry of inorganic materials.

[0006] In a possible implementation, the aluminate is aluminum nitrate or aluminum chloride.

[0007] In a possible implementation, the mass ratio of the inorganic powder to the aluminate is 1:1 - 4.

[0008] In a possible implementation, in step S01, the ultrasonic oscillation time is 15 min - 30 min.

[0009] In a possible implementation, in step S02, the water bath temperature is 50°C - 90°C.

[0010] In a possible implementation, in step S03, the water bath stirring time is 1.5 h - 6 h, and the water bath stirring rate is 300 rpm - 2000 rpm.

[0011] In a possible implementation, in step S04, the thickness of the aluminum oxide coated on the surface of the inorganic powder is 50 nm - 100 nm, the drying temperature is 50°C - 90°C, and the calcination temperature is 600°C - 1200°C.

[0012] In a possible implementation, in step S05, the amine modifier is one or more of triethanolamine and methyldiethanolamine.

[0013] In a possible implementation, in step S07, the prepolymer is one or more of epoxy acrylate and polyurethane acrylate, the monomer is one or more of monofunctional acrylate monomers (HEA, HEMA, ACMO), difunctional acrylate monomers (TPGDA, HDDA, NPGDA), and polyfunctional acrylate monomers (TMPTA), and the photoinitiator is one or more of free radical photoinitiators (BDK, TPO, 819, LAP), cationic photoinitiators (410, 6976), hydrogen abstraction photoinitiators (ITX, DETX), and cleavage photoinitiators (1173, 184).

[0014] In a possible implementation, in step S08, the auxiliary reagents are amine accelerators and dispersants. The amine accelerator is an amine sensitizer (EDB), and the dispersant is one or more of KH-560, KH-570, BYK-9076, and KMT-3032A.

[0015] Compared with the prior art, the solution shown in the embodiments of the present application, a method for preparing a photocurable slurry of the present invention, by coating the surface of inorganic powder with alumina (inorganic material) and amine modifiers (organic material), reduces the agglomeration between inorganic powder particles, improves the dispersibility of inorganic powder in the slurry, reduces the slurry viscosity, improves the photosensitive characteristics of the inorganic material, reduces the refractive index difference between inorganic powder particles and the photosensitive resin, and reduces the absorption and scattering of ultraviolet light by inorganic powder. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0017] Figure 1 It is a process flow chart of a method for preparing a photocurable slurry provided by an embodiment of the present invention; Figure 2 It is an XRD curve of the powder at different calcination temperatures after coating; Figure 3 It is an SEM image, an EDS image, and an EDS energy spectrum diagram of the powder after coating at 1000°C; Figure 4 It is an elemental content diagram of the powder after coating at 1000°C; Figure 5 It is a curve of the addition amount of triethanolamine and the single-layer curing thickness; Figure 6 It is a curve of the addition amount of triethanolamine and the viscosity; Figure 7 TEM image of the powder after coating at 1000 °C; Figure 8 Absorption of ultraviolet light by Al2O3-coated and modified Cr2O3 powder; Figure 9 Fourier transform infrared spectrum of triethanolamine-modified Cr2O3 powder; Figure 10 Fourier transform infrared spectra of the slurry before and after curing. Detailed implementation manners

[0018] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0019] Please refer to Figures 1 to 3 simultaneously, and a preparation method of a photocurable slurry provided by the present invention will be described now. The preparation method of the photocurable slurry includes the following steps: S01: Add inorganic powder and aluminate into ionized water respectively and perform ultrasonic oscillation to obtain a suspension of the inorganic powder; S02: Transfer the suspension to a water bath heating pot; S03: Add an alkaline precipitating agent to the water bath heating pot to control the pH value of the suspension within the range of 9-11, and stir simultaneously. Aluminum oxide precipitate will coat the surface of the inorganic powder; S04: Filter or centrifuge the mixed solution in step S03 to separate the inorganic powder coated with aluminum oxide from the solution, and then obtain the aluminum oxide-coated powder through drying, calcination and grinding; S05: Add an amine modifier and the aluminum oxide-coated powder into absolute ethanol, perform water bath heating and stirring, and the amine modifier will coat the surface of the aluminum oxide-coated powder; S06: Heat and dry the mixed solution in step S05 to remove absolute ethanol, and then obtain the modified powder coated with an amine modifier and aluminum oxide through centrifugation and drying; S07: Perform water bath heating and stirring on the prepolymer, monomer and photoinitiator to obtain a photosensitive resin; S08: Mix and stir the modified powder, photosensitive resin and auxiliary reagents to finally obtain a slurry of inorganic materials.

[0020] A method for preparing a photocurable slurry provided by this embodiment, compared with the prior art, by coating alumina (inorganic material) and amine modifiers (organic materials) on the surface of inorganic powder, thus reducing the agglomeration between inorganic powder particles, improving the dispersibility of inorganic powder in the slurry, reducing the slurry viscosity, improving the photosensitive characteristics of inorganic materials, reducing the refractive index difference between inorganic powder particles and photosensitive resin, and reducing the absorption and scattering of ultraviolet light by inorganic powder.

[0021] Due to the presence of strongly hydrophilic hydroxyl groups on the surface of inorganic powder, inorganic powder is prone to water absorption and agglomeration. In photocurable 3D printing slurries, when inorganic powder is used as a filler material to be compounded with a matrix material, the polarity difference between the surface of inorganic powder and the surface or interface of the photosensitive resin is relatively large, and the compatibility is relatively low. Therefore, it is difficult to disperse uniformly in the matrix material. At the same time, during the slurry preparation process, oxygen molecules dissolved in the air will hinder the photopolymerization process. At the same time, as the oxygen molecules are consumed during the layer-by-layer photocurable 3D printing process, the oxygen molecules in the surface of the cured layer can also quickly diffuse into the interior of the slurry to continue to hinder the polymerization and curing process.

[0022] The present invention introduces amine compounds such as triethanolamine to carry out organic modification on inorganic powder on the basis of inorganic coating. Modifying aids such as triethanolamine are coated or adsorbed on the surface of inorganic powder. During the photocuring process, it can act as a hydrogen donor to provide hydrogen atoms to form hydroxyl groups with oxygen molecules existing in the slurry, reducing the surface tension of the powder, increasing the wettability between the powder and the photosensitive resin, reducing the air content between the powder and the resin, reducing the oxygen content, and reducing the influence of oxygen inhibition of polymerization. At the same time, it can promote the initiation efficiency of photoinitiators in the photosensitive resin system, improve the polymerization efficiency of the photosensitive resin near the inorganic powder, and then improve the curing depth and curing efficiency, thereby ensuring the density and mechanical properties of the photocurable formed parts.

[0023] The present invention is not only applicable to photocurable 3D printing, but also compatible with existing process technologies such as UV coatings and UV inks, and can also be combined with the existing UV curing industry. The process operation is simple, providing an effective solution for improving the UV curing process. The particle size of the inorganic powder is above 100 nm. The inorganic powder includes chromium oxide, zirconium oxide, silicon carbide, silicon nitride, carbon black, titanium dioxide, cemented carbide, etc.

[0024] In some embodiments, the aluminate is aluminum nitrate or aluminum chloride. In this embodiment, in addition to aluminum nitrate or aluminum chloride, it can also be other aluminates containing aluminate radicals.

[0025] In some embodiments, the mass ratio of the inorganic powder to the aluminate is 1:1 - 4. In this embodiment, the mass of the inorganic powder and the aluminate can be any ratio within this range, such as 1:1, 1:2, 1:2.5, 1:3, 1:4.

[0026] In some embodiments, in step S01, the ultrasonic oscillation time is 15 min - 30 min. In this embodiment, the ultrasonic oscillation time can be determined according to the actual dispersion effect.

[0027] In some embodiments, in step S02, the water bath temperature is 50°C - 90°C.

[0028] In some embodiments, in step S03, the water bath stirring time is 1.5 h - 6 h, and the water bath stirring rate is 300 rpm - 2000 rpm.

[0029] In some embodiments, in step S04, the thickness of the alumina coated on the surface of the inorganic powder is 50 nm - 100 nm, the drying temperature is 50°C - 90°C, and the calcination temperature is 600°C - 1200°C. In this embodiment, alumina can effectively improve the photosensitive properties of inorganic materials.

[0030] In some embodiments, in step S05, the amine modifier is one or more of triethanolamine and methyldiethanolamine. In this embodiment, the amine modifier is 2% - 7% of the mass of the alumina-coated powder. The water bath temperature is 40°C - 70°C, the water bath stirring rate is 200 rpm - 1000 rpm, and the water bath stirring time is 0.5 h - 2 h.

[0031] In some embodiments, in step S07, the prepolymer is one or more of epoxy acrylate and polyurethane acrylate, the monomer is one or more of monofunctional acrylate monomers (HEA, HEMA, ACMO), difunctional acrylate monomers (TPGDA, HDDA, NPGDA), and polyfunctional acrylate monomers (TMPTA), and the photoinitiator is one or more of free radical photoinitiators (BDK, TPO, 819, LAP), cationic photoinitiators (410, 6976), hydrogen abstraction photoinitiators (ITX, DETX), and cleavage photoinitiators (1173, 184).

[0032] In some embodiments, in step S08, the auxiliary reagents are amine accelerators and dispersants. The amine accelerator is an amine sensitizer (EDB), and the dispersant is one or more of KH-560, KH-570, BYK-9076, and KMT-3032A.

[0033] Taking the photocuring forming of silicon carbide ceramics as an example: Add 20 g of aluminum nitrate nonahydrate to 100 g of deionized water and ultrasonically vibrate for 12 min. Then add 20 g of silicon carbide, ultrasonically vibrate again for 12 min, and then dropwise add ammonia water to adjust the pH value of the ceramic suspension to 9. Stir at room temperature with an electric stirrer at a rotation speed of 600 rpm for 3 h. Centrifuge, filter, dry, and grind the obtained liquid, and then perform high-temperature sintering. Control the sintering temperature at 1200 °C to obtain silicon carbide powder coated with alumina. Then add the silicon carbide powder coated with alumina to a mixed solution of triethanolamine and absolute ethanol. Triethanolamine accounts for 2% of the mass of the silicon carbide powder coated with alumina. Ultrasonically vibrate for 12 min, heat in a water bath at 65 °C, and stir with an electric stirrer at a rotation speed of 400 rpm for 1 h. After the water bath stirring is completed, heat and dry the mixed solution to remove absolute ethanol. Finally, obtain silicon carbide powder with "inorganic + organic" surface coating modification through centrifugation and drying. Then mix bisphenol A epoxy acrylate, polyurethane acrylate, TPO, 819, HDDA, and TMPTA in a certain proportion. Among them, HDDA and TMPTA account for 55% of the total mass fraction of the photosensitive resin slurry, the mass ratio of HDDA to TMPTA is 6:1, bisphenol A epoxy acrylate accounts for 30% of the mass of the photosensitive resin slurry, polyurethane acrylate accounts for 14% of the mass of the photosensitive resin slurry, and TPO and 819 account for 0.67% and 0.33% of the mass of the photosensitive resin slurry. Stop heating after stirring and dissolving the mixture in a water bath at 80 °C, and then slowly add the modified silicon carbide powder with a solid content of 55% and the dispersant KH-560. The dispersant KH-560 accounts for 2% of the mass of the modified silicon carbide powder. Stir with an electric stirrer at a rotation speed of 600 rpm for 6 h to obtain a photocurable slurry. The prepared slurry can reach a curing thickness of more than 50 microns under ultraviolet light irradiation at 405 nm 90 mw / cm 2 The ultraviolet light irradiation can reach a curing thickness of more than 50 microns.

[0034] Take the photocuring forming of inorganic pigment chromium oxide as an example: As an inorganic powder with a large refractive index difference from the photosensitive resin, it is difficult to perform photocuring forming with a high solid content for chromium oxide. In this case, a chromium oxide photosensitive resin slurry with a solid content of 50% was prepared, and a photocured sample was successfully prepared. The specific preparation process of the surface modification of chromium oxide powder and the photosensitive resin slurry is as follows: Add 40 g of aluminum nitrate nonahydrate to 100 g of deionized water and ultrasonically vibrate for 15 min. Then add 10 - 20 g of chromium oxide, ultrasonically vibrate again for 15 min, and then dropwise add ammonia water to adjust the pH value to 9. Stir at room temperature with an electric stirrer at a rotation speed of 600 rpm for 3 h. Centrifuge, filter, dry, and grind the obtained liquid, and then perform sintering treatment at 1000 °C to obtain chromium oxide powder coated with alumina. Then add the chromium oxide powder coated with alumina to a mixed solution of triethanolamine and an appropriate amount of absolute ethanol, and ultrasonically vibrate for 15 min. Among them, triethanolamine accounts for 8% of the powder mass. Heat in a water bath at 60 °C and stir with an electric stirrer at a rotation speed of 400 rpm for 1 h. After the water bath stirring ends, heat and dry the mixed solution to remove absolute ethanol. Finally, obtain chromium oxide powder with "inorganic + organic" surface coating modification through centrifugation and drying. Then mix bisphenol A epoxy acrylate, polyurethane acrylate, TPO, 819, HDDA, and TMPTA in a certain proportion. Among them, the total mass fraction of HDDA and TMPTA in the photosensitive resin slurry is 55%, the mass ratio of HDDA to TMPTA is 6:1, bisphenol A epoxy acrylate accounts for 30% of the mass of the photosensitive resin slurry, polyurethane acrylate accounts for 14% of the mass of the photosensitive resin slurry, and TPO and 819 account for 0.67% and 0.33% of the mass of the photosensitive resin slurry. Stop heating after stirring and dissolving the mixture in a water bath at 80 °C. Then slowly add a certain proportion of modified chromium oxide powder and dispersant KH-560 to it. The mass of the modified chromium oxide powder accounts for 50% of the total mass of the slurry, and the dispersant KH-560 accounts for 2% of the mass of the modified chromium oxide powder. Stir with an electric stirrer at a rotation speed of 600 rpm for 6 h to obtain a photocurable slurry. The obtained slurry has a curing thickness of 17 μm under ultraviolet light irradiation at 405 nm 4000 μW / cm 2 , and the viscosity of the slurry is 2018 mPa·s, enabling photocurable 3D printing and forming.

[0035] Please refer to Figures 2 to 4 , it can be seen from the analysis of the XRD curves of the modified powder at different calcination temperatures that the optimal calcination temperature for chromium oxide coated with alumina is 1000 °C. Through the analysis of the SEM and EDS images of the powder after coating at 1000 °C, it can be obtained that the distribution positions of Al, O, and Cr elements are roughly the same at this time. At the same time, combined with XRD, it can be concluded that the powder at this position is Cr2O3 and Al2O3. Therefore, it can be seen that a layer of Al2O3 is successfully coated on the surface of Cr2O3. Through calculation, the molar ratio of Cr2O3 to Al2O3 is 67:33, and the thickness of the coating layer is about 12% of the particle size of Cr2O3.

[0036] Although alumina coating reduces the refractive index difference between chromium oxide powder and photosensitive resin to a certain extent, due to the light absorption and other characteristics of chromium oxide powder, the solid content that can be used for photocuring 3D printing after alumina coating is still relatively low and cannot meet the requirements of a higher solid content. Therefore, on the basis of alumina-coated modified chromium oxide powder, organic coating modification treatment is selected.

[0037] To explore the coating situation of Al2O3, SEM and EDS tests were carried out on the powder after coating at 1000 °C, and the test results are as Figure 3 shown. It can be observed from the EDS image that the main elements of the matrix are Cr and O ( Figure 3 c, Figure 3 e), while the main elements of the coating layer are O and Al with relatively uniform distribution ( Figure 3 e, Figure 3 d). At this time, the distribution positions of Al, O, and Cr elements are roughly the same. At the same time, combined with the Figure 2 XRD curve, it can be concluded that the powder at this position is Cr2O3 and Al2O3. Further TEM characterization was carried out on the Al2O3 coating layer. As shown in Figure 7 a, the Al2O3-coated modified Cr2O3 powder particles form an approximate core-shell structure. The Al2O3 nanoparticles are relatively closely distributed on the surface of the Al2O3 powder. Diffraction analysis of a specific area of the Al2O3 coating layer shows that, as shown in Figure 7 c, the Al2O3 coating layer has a crystal structure, and the interplanar spacing is 0.45 nm, which is consistent with the (300) crystal plane of the typical Al2O3 crystal plane. Combining the above analysis, it can be determined that the modified Cr2O3 powder forms a core-shell structure with Al2O3 nanoparticles as the coating layer at 1000 degrees Celsius.

[0038] Please refer to Figure 5 and Figure 6 . According to the single-layer curing thickness of the chromium oxide slurry only coated with alumina is relatively thin and cannot meet the photocuring 3D printing conditions, so the method of triethanolamine modification is used to increase its single-layer curing thickness. The chromium oxide slurry with a solid content of 50 wt% prepared by experiment under ultraviolet light irradiation at 405 nm and 4000 μW / cm 2 can obtain the optimal triethanolamine addition amount of 8%. When the triethanolamine addition amount is 8%, the curing thickness of the slurry reaches the highest value of 17 microns, and the viscosity value of the slurry is 2018 mPa·s, remaining at a relatively low value.

[0039] By comparing the ultraviolet light absorption rates of the powder before and after Al2O3 coating modification, it can be found that after Al2O3-coated modified Cr2O3 powder, the ultraviolet absorption rate of Cr2O3 powder under 405 nm ultraviolet light decreases slightly, as shown in Figure 8 shown. CombiningFigure 2 EDS energy spectrum data analysis shows that the molar ratio of Cr2O3 to Al2O3 is 27:10, and the Al2O3 nanoparticles have a relatively thin coating layer. Through the above analysis, it can be determined that coating and modifying Cr2O3 powder with Al2O3 in the prior art can reduce the ultraviolet light absorption rate of Cr2O3 powder to a certain extent. However, due to the strong ultraviolet light absorption characteristics of Cr2O3 powder, the coating and modification effect of Al2O3 is not good. Therefore, in this application, the coated and modified Cr2O3 powder was further organically modified.

[0040] In this application, FTIR technology was used to analyze the changes in the functional groups on the surface of the powder before and after modification to verify whether the amine modifier TEOA (triethanolamine) reacted with the hydroxyl groups on the powder surface. Through the Fourier transform infrared spectrum of Cr2O3 powder modified by TEOA ( Figure 9 ), it can be observed that the Cr2O3 powder modified by TEOA shows stretching vibration absorption peaks of the O-H bond of TEOA at 2945 cm-1, 2876 cm-1, and 2818 cm-1, and a stretching vibration absorption peak of the N-H bond of TEOA at 3315 cm-1. This indicates that after TEOA is adsorbed on the surface of Cr2O3 powder through hydrogen bonds and undergoes dehydration and condensation, a -Cr-O-C- bond is formed on the surface of Cr2O3 powder particles, forming a network structure covering the surface of Cr2O3 powder, making the surface of Cr2O3 powder particles organic and generating a strong steric hindrance effect, achieving the purpose of organic modification of Cr2O3.

[0041] According to the FT-IR characterization results before and after the slurry solidification (as shown in Figure 10 ), the original Slurry shows stretching vibration absorption peaks of the C=C double bond of the PUA acrylate functional group at 1608 cm-1 and 1639 cm-1, and a stretching vibration absorption peak of the O-H epoxy peak of the EA epoxy acrylate functional group near 979 cm-1. By observing the characteristic absorption peaks of the Post-curing layer after modification, it can be found that compared with the peak spectrum intensity of the original slurry, the absorption peak intensity after Post-curing is significantly reduced, and the characteristic peaks of the C=C double bond and the O-H epoxy characteristic peak of the modified and solidified slurry are significantly reduced. This is because under ultraviolet light irradiation, the C=C double bond and the O-H epoxy bond in the modified slurry successfully participate in the cross-linking and curing reaction of the photosensitive resin system under the activation of the photoinitiator, and the surface-modified slurry has good photocuring performance.

[0042] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A preparation method of a photocuring slurry, characterized in that, It includes the following steps: S01: Add inorganic powder and aluminate into deionized water respectively and carry out ultrasonic oscillation to obtain a suspension of the inorganic powder; S02: Transfer the suspension to a water bath heating pot; S03: Add an alkaline precipitating agent into the water bath heating pot to control the pH value of the suspension within the range of 9 - 11, and stir simultaneously. Aluminum oxide precipitate will coat on the surface of the inorganic powder; S04: Filter or centrifuge the mixed solution in step S03 to separate the inorganic powder coated with aluminum oxide from the solution, and then obtain the aluminum oxide coated powder through drying, calcination and grinding; S05: Add an amine modifier and the aluminum oxide coated powder into anhydrous ethanol, carry out water bath heating and stir. The amine modifier will coat on the surface of the aluminum oxide coated powder; S06: Heat and dry the mixed solution in step S05 to remove anhydrous ethanol, and then obtain the modified powder coated with amine modifier and aluminum oxide through centrifugation and drying; S07: Carry out water bath heating and stir the prepolymer, monomer and photoinitiator to obtain a photosensitive resin; S08: Mix and stir the modified powder, photosensitive resin and auxiliary reagents to finally obtain a slurry of the inorganic material.

2. The preparation method of a photocurable paste according to claim 1, characterized in that, The aluminate is aluminum nitrate or aluminum chloride.

3. The preparation method of a photocurable paste according to claim 1, characterized in that, The mass ratio of the inorganic powder to the aluminate is 1:1 - 4.

4. The preparation method of a photocurable paste as described in claim 1, characterized in that, In step S01, the ultrasonic oscillation time is 15 min - 30 min.

5. The preparation method of a photocurable paste according to claim 1, characterized in that, In step S02, the water bath temperature is 50°C - 90°C.

6. The preparation method of a photocurable paste as claimed in claim 1, characterized in that, In step S03, the water bath stirring time is 1.5 h - 6 h, and the water bath stirring rate is 300 rpm - 2000 rpm.

7. The preparation method of a photocurable paste according to claim 1, characterized in that In step S04, the thickness of the aluminum oxide coated on the surface of the inorganic powder is 50 nm - 100 nm, the drying temperature is 50°C - 90°C, and the calcination temperature is 600°C - 1200°C.

8. The preparation method of a photocurable paste according to claim 1, characterized in that, In step S05, the amine modifier is one or more of triethanolamine and methyldiethanolamine.

9. The preparation method of a photocurable paste according to claim 1, wherein, In step S07, the prepolymer is one or more of epoxy acrylate and polyurethane acrylate, the monomer is one or more of monofunctional acrylate monomers (HEA, HEMA, ACMO), difunctional acrylate monomers (TPGDA, HDDA, NPGDA) and polyfunctional acrylate monomers (TMPTA), and the photoinitiator is one or more of free radical photoinitiators (BDK, TPO, 819, LAP), cationic photoinitiators (410, 6976), hydrogen abstraction photoinitiators (ITX, DETX) and cleavage photoinitiators (1173, 184).

10. The preparation method of a photocurable paste as described in claim 1, characterized in that, In step S08, the auxiliary reagents are amine accelerators and dispersants. The amine accelerator is an amine sensitizer (EDB), and the dispersant is one or more of KH - 560, KH - 570, BYK - 9076 and KMT - 3032A.

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