Ultraviolet light insensitive ceramic powder and high-precision ceramic photocuring slurry prepared based on ultraviolet light insensitive ceramic powder

Abstract

The invention discloses ultraviolet light insensitive ceramic powder and high-precision ceramic photocuring slurry prepared on the basis of the ultraviolet light insensitive ceramic powder, and the ceramic powder is obtained by grafting a silane coupling agent to ceramic powder, then carrying out substitution reaction with acylation modified ultraviolet light insensitive pigment with sulfonate groups, and carrying out post-treatment. The ultraviolet light insensitive ceramic powder provided by the invention can realize regulation and control of intrinsic optical performance of the powder, and the ultraviolet light insensitive ceramic photocuring slurry prepared on the basis of the ultraviolet light insensitive ceramic photocuring slurry reduces transverse broadening and edge over-curing by absorbing scattered light in a curing process, so that the forming precision is improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of processing powder of inorganic compounds for preparing ceramic products, and particularly relates to a kind of ultraviolet light insensitive ceramic powder and high-precision ceramic photocuring slurry prepared based thereon. BACKGROUND

[0002] Stereolithography technology is to obtain a specific shape of ceramic body by layer-by-layer solidification of ceramic slurry containing photosensitive resin, ceramic particles and the like through ultraviolet light polymerization, which can be applied to efficient preparation of ceramic elements with complex shape. Among them, the propagation characteristics (such as energy attenuation, scattering effect) of ultraviolet light in the ceramic slurry directly affect the dimensional accuracy and solidification uniformity of the body structure, which is a key parameter for process control.

[0003] In a homogeneous medium, light field attenuation is usually dominated by absorption. A large number of suspended powders in the ceramic slurry will become scattering centers of incident light, causing multiple scattering, resulting in an increase in photocuring width and reducing the forming precision. In addition, the increase of light scattering aggravates the attenuation of light field intensity in the incident direction, reducing the actual solidification thickness and interlayer adhesion. Some studies show that the degree of scattering attenuation in the direction of ultraviolet light incidence and the degree of radial expansion depend on the volume fraction of ceramic, the size of the particles and the refractive index difference between ceramic and liquid.

[0004] From the aspect of slurry system design, using photosensitive resin with high refractive index to reduce the refractive index difference between ceramic powder can reduce the degree of scattering, increase the solidification depth and improve the processing resolution. In addition, reducing the lateral distribution of ultraviolet light to reduce lateral overcuring, currently, some researchers change the color of the slurry by using inorganic dyes to regulate its absorption performance to the curing laser to achieve high-precision forming, but there are still some shortcomings, such as the inorganic dyes introduced will remain inside the ceramic structure, damaging the ceramic structure. Therefore, it is necessary to develop a new ceramic photocuring slurry that can ensure high-precision forming without damaging the ceramic structure. SUMMARY

[0005] The technical problem to be solved by the present application is to solve the above-mentioned deficiencies in the prior art, and to provide a kind of ultraviolet light insensitive ceramic powder and high-precision ceramic photocuring slurry prepared based thereon. The ceramic powder is obtained by modifying the ceramic powder with organic pigment, and the ceramic photocuring slurry prepared based thereon can effectively reduce the lateral distribution of ultraviolet light to achieve the effect of high-precision forming, while not affecting the performance of the prepared ceramic product.

[0006] To solve the above technical problems, the technical solution provided by the present application is: Provided is an ultraviolet light desensitizing ceramic powder, which is obtained by grafting a silane coupling agent to a ceramic powder, then performing a substitution reaction with an acylated modified ultraviolet light desensitizing pigment having a sulfonate group and post-treatment.

[0007] According to the above scheme, the silane coupling agent is one or more of aminopropyltrimethoxysilane (SCA-1103), aminopropyltriethoxysilane (KH550), γ-glycidoxypropyltrimethoxysilane (KH560), 2-aminoethyl-aminopropyltrimethoxysilane (KH792), diethylenetriaminopropyltrimethoxysilane (SCA-1503), 3-(2-aminoethylamino)propylmethyldimethoxysilane, bis(3-trimethoxysilylpropyl)amine, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane (SCA-602), 3-(octanoylthio)propyltriethoxysilane (NXT), 3-propionylthiopropyltriethoxysilane (PXT), and 3-aminopropyltrimethoxysilane. The silane coupling agent can activate the surface of the ceramic powder and introduce a chemically active group.

[0008] According to the above scheme, the ceramic powder is one or more of alumina, zirconia, silicon carbide, silicon nitride, barium titanate (BaTiO3), ceria, β-tricalcium phosphate, trimagnesium phosphate, hydroxyapatite, ceria, whitlockite, tetracalcium phosphate, and octacalcium phosphate. The ceramic powder is a powder having a uniform particle size or a mixture of powders having different particle sizes, and the particle size is 0.1-100 μm.

[0009] According to the above scheme, the method for preparing the acylated modified ultraviolet light desensitizing pigment having a sulfonate group is as follows: mixing the ultraviolet light desensitizing pigment having a sulfonate group, a chlorinating agent, and a catalyst in a mass ratio of 1-10:2-20:0-1, and reacting at 0-130°C for 0.5-12 h under an inert atmosphere. After the reaction is complete, the temperature is returned to room temperature, the mixture is filtered, the obtained filter cake is washed with dilute hydrochloric acid and water in sequence, and then dried to obtain the acylated modified ultraviolet light desensitizing pigment.

[0010] According to the above scheme, the chlorinating agent is one of thionyl chloride, chlorosulfonic acid, phosphorus oxychloride, and phosphorus pentachloride, and the catalyst is one of N,N-dimethylformamide, triethylamine, and pyridine. Chlorosulfonic acid can also be used as a catalyst, so when the chlorinating agent is chlorosulfonic acid, no catalyst needs to be added.

[0011] According to the above scheme, the ultraviolet light desensitizing pigment with sulfonate group is one or more of 6-hydroxy-5-(2-methoxy-4-sulfonic acid-5-methylphenyl) azo naphthalene-2-sulfonic acid disodium salt (CAS: 25956-17-6), 1-(4'-sulfonic acid-1'-naphthalene azo)-2-naphthol-6,8-disulfonic acid trisodium salt (CAS: 15876-47-8), 6-hydroxy-5-[(4-sulfonic acid phenyl)azo]-2-naphthalene sulfonic acid disodium salt (CAS: 2783-94-0), 1-(4-sulfonic acid phenyl)-4-(4-sulfonic acid phenyl azo)-5-pyrazolone-3-carboxylic acid trisodium salt (CAS: 1934-21-0), 1-acetylamino-2-hydroxy-3-(4-(4-sulfonic acid phenyl azo)-7-sulfonic acid-1-naphthalene azo) naphthalene-4,6-disulfonic acid salt (CAS: 2118-39-0), bis[4-(N-ethyl-N-3-sulfonic acid benzyl) aminophenyl]-2-sulfonic acid toluene disodium salt (CAS: 3844-45-9), 3,3'-dioxo-2,2'-biindolyl-5,5'-disulfonic acid disodium salt (CAS: 860-22-0). The organic pigment molecule containing sulfonic acid group can be firmly grafted to the surface of ceramic powder through sulfonylation reaction.

[0012] The present application also includes a preparation method of the above ultraviolet light desensitizing ceramic powder, and the specific steps are as follows: 1) Dissolve silane coupling agent in ethanol to obtain a silane coupling agent solution, then add ceramic powder into the silane coupling agent solution to perform grafting reaction, and then perform post-treatment to obtain silane coupling agent grafted ceramic powder; 2) Dissolve acylated modified ultraviolet light desensitizing pigment with sulfonate group in ethanol to obtain an acylated modified pigment solution, add the silane coupling agent grafted ceramic powder obtained in step 1) into the acylated modified pigment solution to perform substitution reaction, and then perform post-treatment after the reaction to obtain ultraviolet light desensitizing ceramic powder.

[0013] According to the above scheme, the concentration of the silane coupling agent solution in step 1) is 5-40 wt%.

[0014] According to the above scheme, the amount of ceramic powder added in step 1) is 10-70 vol% of the volume of the silane coupling agent solution.

[0015] According to the above scheme, the grafting reaction conditions in step 1) are stirring reaction at 10-60℃ for 4-48h.

[0016] According to the above scheme, the post-treatment step in step 1) is filtering the reaction solution, washing the obtained filter cake with ethanol and water alternately, and then drying at 30-80℃ to obtain silane coupling agent grafted ceramic powder.

[0017] According to the above scheme, the concentration of the acylated modified pigment solution in step 2) is 0.1-20 wt%.

[0018] According to the above scheme, the amount of the silane coupling agent grafted ceramic powder added in step 2) is 10-70 vol% of the volume of the acylated modified pigment solution.

[0019] According to the above scheme, the substitution reaction conditions in step 2) are 10-60℃ for 4-72h.

[0020] According to the above scheme, the post-treatment step in step 2) is: filtering the reaction solution, washing the obtained filter cake with ethanol and water alternately, and then drying at 30-80℃ to obtain the ultraviolet light insensitive ceramic powder.

[0021] The present application also includes a high-precision ceramic photocuring slurry prepared based on the above ultraviolet light insensitive ceramic powder, which is obtained by uniformly mixing the ultraviolet light insensitive ceramic powder, a photosensitive resin and a photoinitiator.

[0022] According to the above scheme, the photosensitive resin is one or more of acryloyl morpholine, isobornyl acrylate, isobornyl methacrylate, hydroxyethyl methacrylate, tetrahydrofuran acrylate, cyclic trimethylolpropane formal acrylate, 4-hydroxybutyl acrylate, o-phenylphenoxyethyl acrylate, ethoxyethoxyethyl acrylate, hydroxybutyl methacrylate, 1,6-hexanediol diacrylate, propoxylated neopentyl glycol diacrylate, tridecane dimethanol diacrylate, tripropylene glycol diacrylate, dipropylene glycol diacrylate (DPGDA), polyethylene glycol dimethacrylate, polyethylene glycol diacrylate, ethoxylated trimethylolpropane triacrylate, trimethylolpropane triacrylate, ethoxylated pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, pentaerythritol triacrylate, trimethylolpropane trimethacrylate, the addition amount of which is 1-7 times the volume of the ultraviolet light insensitive ceramic powder. The photosensitive resin selected in the present application can make the ultraviolet light insensitive ceramic powder stably dispersed and stored therein.

[0023] According to the above scheme, the photoinitiator is one or more of 2-hydroxy-2-methyl-1-phenylpropanone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropanone, 2,2-dimethoxy-2-phenylacetophenone (photoinitiator 651), 2,4,6-trimethylbenzoyldiphenyl phosphine oxide, 2-isopropylthioxanthone (CAS: 5495-84-1), p-N,N-dimethylaminobenzoic acid ethyl ester (CAS: 10287-53-3), benzophenone, 4-chlorobenzophenone, methyl o-benzoylbenzoate (CAS: 606-28-0), diphenyl iodonium hexafluorophosphate, p-N,N-dimethylaminobenzoic acid isooctyl ester (CAS: 21245-02-3), 4-methylbenzophenone, 4-phenylbenzophenone, 2,4,6-trimethylbenzoyl phenyl phosphonate, 2,4-diethylthioxanthone, 2-hydroxy-4-(2-hydroxyethoxy)-2-methylpropiophenone, and the addition amount is 0.05-10wt% of the mass of the photosensitive resin.

[0024] The application also includes a ceramic prepared from the high-precision ceramic photocuring slurry.

[0025] The application first constructs high-activity reaction sites on the surface of the ceramic powder by using a silane coupling agent, and then uses surface grafting technology to compound organic pigment molecules (acylated modified ultraviolet light insensitive pigments with sulfonate groups, which have strong absorption effect on 355 mu m, 365 mu m and 405 mu m band ultraviolet light) with specific optical properties to the powder surface. The obtained surface modified ceramic powder has stable properties and does not react with conventional photosensitive resin. The ceramic slurry can be stored for a long time after preparation, and the organic pigment molecules can be completely removed during subsequent ceramic preparation through debinding and sintering, without bringing negative effects to the ceramic components.

[0026] In addition, the surface modified ceramic powder provided by the application can effectively regulate light scattering in the process of ceramic photocuring additive manufacturing, significantly improve the printing precision, and at the same time, the modification reaction degree of the powder surface or the addition amount of the modified powder can be adjusted according to the actual printing requirements to realize accurate adaptation to the process requirements. The application avoids the use of traditional ceramic slurry optical additives, avoids the problems of increased slurry toxicity, decreased stability and low mechanical properties of the formed blank caused by excessive use of small molecule optical additives, and also avoids the problem of sintering residue of some inorganic optical additives after processing, so that the quality of the additive manufacturing blank is good, the yield is high, and the mechanical properties of the blank are good, and the subsequent sintering can be carried out without secondary curing.

[0027] The beneficial effects of the present application are: 1. The ultraviolet light insensitive ceramic powder of the present application can realize the intrinsic optical performance regulation of the powder, and the ultraviolet light insensitive ceramic photocuring slurry prepared based thereon can absorb scattered light in the curing process, reduce lateral broadening and edge overcuring, thereby improving the forming precision. 2. The preparation method of the present application has simple steps and mild reaction conditions, is suitable for industrial application, and has strong universality for ceramic powder types, which is beneficial to realize high-precision processing of various ceramic materials. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The physical photos of the alumina powder of Comparative Example 1, the silane coupling agent grafted ceramic powder prepared in step 1) of Example 1, the silane coupling agent grafted ceramic powder prepared in step 1) of Example 2, and the silane coupling agent grafted ceramic powder prepared in step 1) of Example 5, and the corresponding ceramic photocuring slurry of each powder; Figure 2 The physical photos of the finished products obtained by 3D printing using the ceramic photocuring slurry of Example 5 (upper) and Comparative Example 2 (lower) as raw materials; Figure 3 The SEM photos of the precision test samples obtained by 3D printing using the ceramic photocuring slurry of Comparative Example 1 (before modification) and Example 1 (after modification) as raw materials. DETAILED DESCRIPTION

[0029] In order for those skilled in the art to better understand the technical solutions of the present application, the present application will be further described in detail below with reference to the drawings.

[0030] Example 1 An ultraviolet light insensitive ceramic powder, and the preparation method thereof is as follows: 1) Dissolve KH550 silane coupling agent in ethanol to prepare a 2L silane coupling agent solution with a concentration of 10wt%, then add 1kg of alumina with a particle size of 2μm and 1kg of alumina with a particle size of 5μm to the silane coupling agent solution, the volume of the ceramic powder is about 25vol% of the volume of the silane coupling agent solution, stir the reaction at 30℃ for 24h, after the reaction is completed, filter the reaction solution, wash the obtained filter cake with ethanol and water alternately, and then dry it at 60℃ to obtain a silane coupling agent grafted ceramic powder; 2) Mix 5g of 6-hydroxy-5-(2-methoxy-4-sulfonic acid-5-tolyl) azonaphthalene-2-sulfonic acid disodium salt, 10g of thionyl chloride and 1g of pyridine, and react at 50℃ for 4h under nitrogen protection, after the reaction is completed, cool to room temperature, filter, wash the obtained filter cake with dilute hydrochloric acid and water in turn, and then freeze dry at-40℃ for 48h to obtain an acylated modified ultraviolet light insensitive pigment; 3) The acylated modified ultraviolet light blunting pigment obtained in step 2) is dissolved in ethanol to prepare an acylated modified pigment solution with a concentration of 5 wt% in 1 L. The silane coupling agent grafted ceramic powder obtained in step 1) is added to the acylated modified pigment solution, and the amount of the silane coupling agent grafted ceramic powder added is 25 vol% of the acylated modified pigment solution. The reaction is stirred at 25°C for 24 h. After the reaction is completed, the reaction solution is filtered, the solid product is washed with ethanol and water alternately, and finally dried at 60°C to obtain an ultraviolet light blunting ceramic powder.

[0031] The ultraviolet light blunting ceramic powder obtained in this example is mixed with a photosensitive resin (4-hydroxybutyl acrylate, hydroxybutyl methacrylate and trimethylolpropane trimethacrylate in a mass ratio of 1:1:1), and a photoinitiator 2,4,6-trimethylbenzoyl diphenyl phosphine oxide. The amount of the photosensitive resin added is 1.22 times the volume of the ultraviolet light blunting ceramic powder, and the amount of the photoinitiator is 2 wt% of the total amount of the photosensitive resin. After being stirred uniformly, a ceramic photocuring slurry is obtained.

[0032] Example 2 An ultraviolet light blunting ceramic powder is prepared by the following method: 1) KH792 silane coupling agent is dissolved in ethanol to prepare a silane coupling agent solution with a concentration of 20 wt% in 1.5 L. Then, 4.4 kg of zirconia ceramic powder with a particle size of 10 μm is added to the silane coupling agent solution, and the volume of the ceramic powder is about 50 vol% of the volume of the silane coupling agent solution. The reaction is stirred at 50°C for 12 h. After the reaction is completed, the reaction solution is filtered, and the obtained filter cake is washed with ethanol and water alternately and then dried to obtain a silane coupling agent grafted ceramic powder; 2) 5 g of 6-hydroxy-5-[(4-sulfonic acid phenyl) azo]-2-naphthalenesulfonic acid disodium salt is mixed with 10 g of chlorosulfonic acid, and the mixture is reacted at 120°C for 0.5 h under nitrogen protection. After the reaction is completed, the mixture is cooled to room temperature, filtered, and the obtained filter cake is washed with dilute hydrochloric acid and water successively, and then freeze-dried to obtain an acylated modified ultraviolet light blunting pigment; 3) The acylated modified ultraviolet light blunting pigment obtained in step 2) is dissolved in ethanol to prepare an acylated modified pigment solution with a concentration of 20 wt% in 1 L. The silane coupling agent grafted ceramic powder obtained in step 1) is added to the acylated modified pigment solution, and the amount of the silane coupling agent grafted ceramic powder added is 40 vol% of the acylated modified pigment solution. The reaction is stirred at 40°C for 12 h. After the reaction is completed, the reaction solution is filtered, the solid product is washed with ethanol and water alternately, and finally dried at 40°C to obtain an ultraviolet light blunting ceramic powder.

[0033] The ultraviolet light insensitive ceramic powder obtained in this example is mixed with a photosensitive resin (1,6-hexanediol diacrylate, trimethylolpropane triacrylate and trimethylolpropane trimethacrylate mixed at a mass ratio of 1:2:1), and a photoinitiator 1-hydroxycyclohexyl phenyl ketone, wherein the photosensitive resin is added in an amount of 3 times the volume of the ultraviolet light insensitive ceramic powder, and the photoinitiator is used in an amount of 1 wt% of the total amount of the photosensitive resin, and after being fully and uniformly stirred, a ceramic photocuring slurry is obtained.

[0034] Example 3 An ultraviolet light insensitive ceramic powder is prepared by the following method: 1) SCA-602 silane coupling agent is dissolved in ethanol to prepare a 2L silane coupling agent solution with a concentration of 35 wt%, and then 2.4kg of silicon carbide ceramic powder with a particle size of 4μm is added to the silane coupling agent solution, and the volume of the ceramic powder is about 35vol% of the volume of the silane coupling agent solution, and the reaction is stirred at 25℃ for 48h, and after the reaction is completed, the reaction solution is filtered, and the obtained filter cake is washed with ethanol and water alternately and then dried to obtain a silane coupling agent grafted ceramic powder; 2) 5g of 1-(4-sulfonic acid phenyl)-4-(4-sulfonic acid phenyl azo)-5-pyrazolone-3-carboxylic acid trisodium salt is mixed with 10g of phosphorus pentachloride and 1g of N,N-dimethylformamide, and the reaction is carried out at 0℃ for 3h under nitrogen protection, and after the reaction is completed, it is cooled to room temperature, filtered, and the obtained filter cake is washed with dilute hydrochloric acid and water alternately, and then freeze-dried to obtain an acylated modified ultraviolet light insensitive pigment; 3) The acylated modified ultraviolet light insensitive pigment obtained in step 2) is dissolved in ethanol to prepare a 1L acylated modified pigment solution with a concentration of 1wt%, and the silane coupling agent grafted ceramic powder obtained in step 1) is added to the acylated modified pigment solution, and the amount of the silane coupling agent grafted ceramic powder added is 20vol% of the acylated modified pigment solution, and the reaction is stirred at 60℃ for 8h, and after the reaction is completed, the obtained reaction solution is filtered, and the solid product is washed with ethanol and water alternately, and finally dried at 60℃ to obtain an ultraviolet light insensitive ceramic powder.

[0035] The ultraviolet light insensitive ceramic powder obtained in this example is mixed with a photosensitive resin (4-hydroxybutyl acrylate, propoxyl neopentyl glycol diacrylate and trimethylolpropane triacrylate mixed at a mass ratio of 2:2:1), and a photoinitiator 4-phenyl benzophenone, wherein the volume of the photosensitive resin is the same as the volume of the ultraviolet light insensitive ceramic powder, and the amount of the photoinitiator is 10wt% of the total amount of the photosensitive resin, and after being fully and uniformly stirred, a ceramic photocuring slurry is obtained.

[0036] Example 4 An ultraviolet light insensitive ceramic powder is prepared by the following method: 1) 3-(2-aminoethylamino)propylmethyldimethoxysilane was dissolved in ethanol to prepare a silane coupling agent solution with a concentration of 5 wt% in 3 L, and then 5.8 kg of silicon nitride ceramic powder with a particle size of 30 μm was added to the silane coupling agent solution, the volume of the ceramic powder being about 60 vol% of the volume of the silane coupling agent solution, and the mixture was stirred at 60°C for 48 h. After the reaction was completed, the reaction solution was filtered, the obtained filter cake was washed with ethanol and water alternately, and then dried to obtain a silane coupling agent grafted ceramic powder; 2) 5 g of 3,3'-dioxo-2,2'-biindolyl-5,5'-disulfonic acid disodium salt was mixed with 10 g of chlorosulfoxide and 1 g of triethylamine, and the mixture was reacted at 40°C for 8 h under nitrogen protection. After the reaction was completed, the mixture was cooled to room temperature, filtered, and the obtained filter cake was washed with dilute hydrochloric acid and water, and then freeze-dried to obtain an acylated modified ultraviolet light-insensitive pigment; 3) The acylated modified ultraviolet light-insensitive pigment obtained in step 2) was dissolved in ethanol to prepare an acylated modified pigment solution with a concentration of 20 wt% in 2 L, and then the silane coupling agent grafted ceramic powder obtained in step 1) was added to the acylated modified pigment solution, the amount of the silane coupling agent grafted ceramic powder being 40 vol% of the acylated modified pigment solution, and the mixture was stirred at 25°C for 72 h. After the reaction was completed, the reaction solution was filtered, the solid product was washed with ethanol and water alternately, and then dried to obtain an ultraviolet light-insensitive ceramic powder.

[0037] The ultraviolet light-insensitive ceramic powder obtained in this example was mixed with a photosensitive resin (acryloylmorpholine, 4-hydroxybutyl acrylate, 1,6-hexanediol diacrylate, and dipentaerythritol hexaacrylate at a mass ratio of 1:2:2:1), and a photoinitiator methyl o-benzoylbenzoate, wherein the amount of the photosensitive resin was 2.33 times the volume of the ultraviolet light-insensitive ceramic powder, and the amount of the photoinitiator was 8 wt% of the total amount of the photosensitive resin. After the mixture was stirred uniformly, a ceramic photocuring slurry was obtained.

[0038] Example 5 An ultraviolet light-insensitive ceramic powder was prepared by the following method: 1) SCA-1103 silane coupling agent was dissolved in ethanol to prepare a silane coupling agent solution with a concentration of 25 wt% in 0.5 L, and then 0.8 kg of β-tricalcium phosphate ceramic powder with a particle size of 0.8 μm was added to the silane coupling agent solution, the volume of the ceramic powder being about 50 vol% of the volume of the silane coupling agent solution, and the mixture was stirred at 40°C for 12 h. After the reaction was completed, the reaction solution was filtered, the obtained filter cake was washed with ethanol and water alternately, and then dried to obtain a silane coupling agent grafted ceramic powder; 2) 5 g of 1-acetylamino-2-hydroxy-3-(4-(4-sulfonatophenylazo)-7-sulfonatophenylazo)- 1-naphthalene-4,6-disulfonate is mixed with 10 g of phosphorus oxychloride and 1 g of pyridine, and reacted at 0°C for 12 h under nitrogen protection. After the reaction is completed, it is cooled to room temperature, filtered, and the obtained filter cake is washed with dilute hydrochloric acid and water in sequence, and then freeze-dried to obtain an acylated modified ultraviolet light non-sensitive pigment; 3) The acylated modified ultraviolet light non-sensitive pigment obtained in step 2) is dissolved in ethanol to prepare 0.5 L of an acylated modified pigment solution with a concentration of 15 wt%. The silane coupling agent grafted ceramic powder obtained in step 1) is added to the acylated modified pigment solution, and the amount of the silane coupling agent grafted ceramic powder added is 40 vol% of the acylated modified pigment solution. The reaction is stirred at 25°C for 24 h. After the reaction is completed, the obtained reaction solution is filtered, and the solid product is washed with ethanol and water in sequence, and then dried to obtain an ultraviolet light non-sensitive ceramic powder.

[0039] The ultraviolet light non-sensitive ceramic powder obtained in this example is mixed with a photosensitive resin (a mixture of hydroxyethyl methacrylate, propoxylated neopentyl glycol dipropenoate and dipentaerythritol hexapropenoate at a mass ratio of 5:3:2), and a photoinitiator 2-hydroxy-2-methyl-1-phenylpropanone. The volume of the photosensitive resin added is the same as that of the ultraviolet light non-sensitive ceramic powder, and the amount of the photoinitiator is 2 wt% of the total amount of the photosensitive resin. After being uniformly stirred, a ceramic photocuring slurry is obtained.

[0040] Example 6 An ultraviolet light non-sensitive ceramic powder is prepared by the following method: 1) 0.8 kg of phosphoric acid trimagnesium ceramic powder with a particle size of 1.6 μm is added to a silane coupling agent solution prepared by dissolving KH550 silane coupling agent in ethanol to obtain a silane coupling agent solution with a concentration of 20 wt%, and the volume of the ceramic powder is about 70 vol% of the volume of the silane coupling agent solution. The reaction is stirred at 35°C for 24 h. After the reaction is completed, the reaction solution is filtered, and the obtained filter cake is washed with ethanol and water in sequence, and then dried to obtain a silane coupling agent grafted ceramic powder; 2) 5 g of 1-acetylamino-2-hydroxy-3-(4-(4-sulfonatophenylazo)-7-sulfonatophenylazo)- 1-naphthalene-4,6-disulfonate is mixed with 10 g of chlorosulfonic acid, and reacted at 130°C for 8 h under nitrogen protection. After the reaction is completed, it is cooled to room temperature, filtered, and the obtained filter cake is washed with dilute hydrochloric acid and water in sequence, and then freeze-dried to obtain an acylated modified ultraviolet light non-sensitive pigment; 3) The acylated modified ultraviolet light blunting pigment obtained in step 2) is dissolved in ethanol to prepare an acylated modified pigment solution with a concentration of 8 wt% in 0.5 L. The silane coupling agent grafted ceramic powder obtained in step 1) is added to the acylated modified pigment solution, and the amount of the silane coupling agent grafted ceramic powder added is 40 vol% of the acylated modified pigment solution. The reaction is stirred at 25°C for 12 h. After the reaction is completed, the reaction solution is filtered, and the solid product is washed with ethanol and water alternately. Finally, the product is dried at 80°C to obtain an ultraviolet light blunting ceramic powder.

[0041] The ultraviolet light blunting ceramic powder obtained in this example is mixed with a photosensitive resin (a mixture of hydroxybutyl methacrylate, tripropylene glycol diacrylate and ethoxylated trimethylolpropane triacrylate at a mass ratio of 1:2:1), and a photoinitiator, isooctyl p-N,N-dimethylaminobenzoate. The amount of the photosensitive resin added is 1.22 times the volume of the ultraviolet light blunting ceramic powder, and the amount of the photoinitiator is 1.5 wt% of the total amount of the photosensitive resin. After being stirred uniformly, a ceramic photocuring slurry is obtained.

[0042] Example 7 An ultraviolet light blunting ceramic powder is prepared by the following method: 1) SCA-1503 silane coupling agent is dissolved in ethanol to prepare a silane coupling agent solution with a concentration of 15 wt% in 1 L. Then, 1.5 kg of hydroxyapatite ceramic powder with a particle size of 2 μm is added to the silane coupling agent solution, and the volume of the ceramic powder is about 50 vol% of the volume of the silane coupling agent solution. The reaction is stirred at 50°C for 4 h. After the reaction is completed, the reaction solution is filtered, and the obtained filter cake is washed with ethanol and water alternately and then dried to obtain a silane coupling agent grafted ceramic powder. 2) 5 g of bis[4-(N-ethyl-N-3-sulfobenzyl)aminophenyl]-2-sulfotolyl disodium salt, 10 g of phosphorus pentachloride and 1 g of triethylamine are mixed and reacted at 0°C for 4 h under nitrogen protection. After the reaction is completed, the reaction solution is cooled to room temperature, filtered, and the obtained filter cake is washed with dilute hydrochloric acid and water, and then freeze-dried to obtain an acylated modified ultraviolet light blunting pigment. 3) The acylated modified ultraviolet light blunting pigment obtained in step 2) is dissolved in ethanol to prepare an acylated modified pigment solution with a concentration of 10 wt% in 1 L. The silane coupling agent grafted ceramic powder obtained in step 1) is added to the acylated modified pigment solution, and the amount of the silane coupling agent grafted ceramic powder added is 40 vol% of the acylated modified pigment solution. The reaction is stirred at 25°C for 24 h. After the reaction is completed, the reaction solution is filtered, and the solid product is washed with ethanol and water alternately. Finally, the product is dried to obtain an ultraviolet light blunting ceramic powder.

[0043] The ultraviolet light insensitive ceramic powder obtained in the present example is mixed with a photosensitive resin (acryloylmorpholine, cyclotrimethylolpropane formal acrylate and tri-decane dimethanol diacrylate are mixed in a mass ratio of 1:1:1), and a photoinitiator 2-hydroxy-4-(2-hydroxyethoxy)-2-methylpropiophenone, wherein the volume of the photosensitive resin added is the same as the volume of the ultraviolet light insensitive ceramic powder, and the amount of the photoinitiator is 2wt% of the total amount of the photosensitive resin. After being fully homogenously stirred, a ceramic photocuring slurry is obtained.

[0044] Comparative Example 1 A ceramic photocuring slurry is prepared in a similar manner as in Example 1, except that the ultraviolet light insensitive ceramic powder is replaced by an equal amount of alumina powder with a particle size of 5μm.

[0045] Comparative Example 2 A ceramic photocuring slurry is prepared in a similar manner as in Example 1, except that the ultraviolet light insensitive ceramic powder is replaced by an equal amount of β-tricalcium phosphate with a particle size of 0.8μm.

[0046] Comparative Example 3 A ceramic photocuring slurry is prepared in a similar manner as in Example 1, except that the ultraviolet light insensitive ceramic powder is replaced by an equal amount of trimesium phosphate with a particle size of 1.6μm.

[0047] Figure 1 The above are photos of the alumina powder of Comparative Example 1, the silane coupling agent grafted ceramic powder prepared in step 1) of Example 1, the silane coupling agent grafted ceramic powder prepared in step 1) of Example 2, and the silane coupling agent grafted ceramic powder prepared in step 1) of Example 5, and the below are photos of the corresponding ceramic photocuring slurries of the powders.

[0048] Figure 2 The ceramic photocuring slurries of Example 5 (above) and Comparative Example 2 (below) are used as raw materials to print the same porous model using a C900 Flex (France, 3D Ceram) SLA photocuring 3D printer with a laser power of 80mW, a scanning interval of 0.05mm, and a solidification laser scanning speed of 8000mm / s. It can be seen from the comparison that the ceramic slurry prepared from the ultraviolet light insensitive ceramic powder obtained by the method of the present application has greatly improved component precision compared with the slurry prepared from the unmodified powder, ensuring the existence of small connected structures in the model and the ability to transmit light. The small structures of the slurry prepared from the unmodified powder are blocked and cannot transmit light.

[0049] Figure 3The ceramic photocuring slurry of the comparative example 1 (before modification) and the example 1 (after modification) was used as raw material, a C900 Flex (France, 3D Ceram) SLA photocuring 3D printer was used, the laser power was 80 mW, the scanning interval was 0.05 mm, the curing laser scanning speed was 8000 mm / s, and the SEM image of the printed square test sample was tested. It can be seen that, compared with the slurry prepared from the unmodified powder, the ceramic slurry prepared from the ultraviolet light insensitive ceramic powder obtained by the method has greatly improved component precision, which can ensure the basic structure of the test sample. The slurry prepared from the unmodified powder has a sharp detail distortion, and obvious over-curing effect is generated, and it does not have the ability to prepare high-precision samples.

[0050] Test example 1 First, the ceramic photocuring slurry obtained by examples 1-7 and comparative examples 1-3 was made into a photocuring blank, a C900 Flex (France, 3D Ceram) SLA photocuring 3D printer was used, the laser power was 80 mW, the scanning interval was 0.05 mm, the curing laser scanning speed was 8000 mm / s, and a 10.0 mm±0.2 mm right cube with a porous feature and a porosity of 60% was prepared.

[0051] The photocuring precision test was carried out on the ceramic photocuring slurry prepared by examples 1-7 and comparative examples 1-3, the forming precision of the photocuring blank manufactured by using the ultraviolet light insensitive ceramic slurry was determined according to the standards of “GB / T 39329-2020 additive manufacturing test method standard test piece precision test” and “GB / T 16594-2008 scanning electron microscope measurement method general rule for micron level length”, and the specific method was as follows: 1) The standard substance was fixed on a height-adjustable sample column, and the standard length was required to be perpendicular to the sample column; 2) The standard sample column was placed on the sample stage of the upright metallographic microscope, and the metallographic microscope was adjusted to make the standard length in focus; 3) The state of the metallographic microscope was changed, the standard sample column was removed from the sample stage of the metallographic microscope, the measured sample was replaced, and then the height of the measured sample column was adjusted to make the measured length in focus; 4) The standard sample column and the measured sample column were simultaneously and firmly installed on the sample stage of the scanning electron microscope, and if convenient, the standard length and the measured length direction should be made close to parallel; 5) After the scanning electron microscope was adjusted to the best state, the lens current was finely adjusted to make the image accurately in focus, and the image of the standard length was obtained; 6) Without changing the state of the scanning electron microscope, the measured length image is translated to the middle of the field of view, and if necessary, the sample stage is rotated or translated so that the direction of the measured length image in the field of view is the same as that of the standard length image and is in the middle of the field of view. After fine-tuning the lens current to accurately focus the image, the image of the measured length is obtained, and the length value in the secondary electron image is directly measured by the image measuring device. At least 3 parallel samples are set for each group of experiments, and the middle value is taken. The test results of the minimum typical structural feature size accuracy are shown in Table 1: Table 1

[0052] From the above table, it can be seen that the accuracy of the ceramic photocuring slurry photocuring molding samples prepared in Examples 1-7 is ≤±0.08, and compared with Comparative Examples 1-3, the accuracy of the minimum typical structural feature size is improved by one order of magnitude. It can be considered that the ceramic photocuring slurry prepared in Examples 1-7 can greatly improve the molding accuracy of photocured ceramics.

[0053] Test Example 2 The green body strength of the ceramic photocuring slurry prepared in Examples 1-7 and Comparative Examples 1-3 was tested. The specific implementation method is as follows according to the standard of GB / T 1964-2023 Porous Ceramic Compression Strength Test Method: 1) A C900 Flex (France, 3D Ceram) SLA photocuring 3D printer was used, the laser power was 100 mW, the scanning interval was 0.05 mm, and the solidification laser scanning speed was 8000 mm / s. A right cube with a side length of 10.0 mm±0.2 mm was prepared, and at least 5 samples of each sample were prepared; 2) The sample was placed in an oven and dried at a temperature of 60±5℃ for 2h, and then placed in a dryer and cooled to room temperature; 3) The length or diameter of the sample under compression area was measured, and the area was calculated; 4) The sample was placed at the center of the lower plate of the material testing machine, and the load was applied at a rate of 1.5~2.5MPa / s until the sample was destroyed. The maximum load value at the time of sample destruction was read. When the high-porosity sample had no obvious destruction phenomenon, the sample was taken as the sample destruction point when the height changed by 10%.

[0054] At least 3 parallel samples were set for each group of experiments, and the middle value was taken. The test results are shown in Table 2.

[0055] Table 2

[0056] From the above table, the compression strength of the ceramic photocured slurry photocured green bodies prepared in Examples 1-7 are all ≥ 6.4 MPa, compared with Comparative Examples 1-3, the mechanical properties of the green bodies can be effectively improved, the reliability of the green body preparation process is ensured, and the green bodies can be post-processed and sintered without secondary curing. In contrast, the compression strength of Comparative Examples 1-3 is all less than 5 MPa, and there is a risk of damage in subsequent operations.

[0057] It should be understood that, for those skilled in the art, improvements or changes can be made according to the above description, and all these improvements and changes shall belong to the protection scope of the appended claims of the present application.

Claims

1. A UV-insensitive ceramic powder, characterized in that: The ceramic powder is obtained by grafting a silane coupling agent onto a ceramic powder, and then undergoing a substitution reaction with an acylated modified ultraviolet light insensitive pigment having a sulfonate group and post-processing.

2. The ultraviolet light insensitive ceramic powder according to claim 1, characterized in that The silane coupling agent is aminopropyltrimethoxysilane, aminopropyltriethoxysilane, γ-glycidyloxypropyltrimethoxysilane, 2-aminoethyl-aminopropyltrimethoxysilane, diethylenetriaminopropyltrimethoxysilane, 3-(2-aminoethylamino)propylmethyldimethoxysilane, bis(3-trimethoxysilylpropyl)amine, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-(octanoylthio)propyltriethyl One or more of oxysilane, 3-propionylthiopropyltriethoxysilane, and 3-aminopropyltrimethoxysilane; the ceramic powder is one or more of alumina, zirconium oxide, silicon carbide, silicon nitride, barium titanate, cerium oxide, β-tricalcium phosphate, trimagnesium phosphate, hydroxyapatite, cerium oxide, white apatite, tetracalcium phosphate, and octacalcium phosphate; the ceramic powder is a powder with uniform particle size or a mixture of powders of different particle sizes, and the particle size is 0.1-100 μm.

3. The ultraviolet light insensitive ceramic powder according to claim 1, characterized in that The preparation method of the acylated modified ultraviolet light insensitive pigment having a sulfonate group is as follows: the ultraviolet light insensitive pigment having a sulfonate group, a chlorinating agent and a catalyst are mixed in a mass ratio of 1-10:2-20:0-1, reacted at 0-130°C under an inert atmosphere for 0.5-12 hours, and after the reaction is complete, the temperature is returned to room temperature, filtered, and the obtained filter cake is washed with dilute hydrochloric acid and water in sequence, and then dried to obtain the acylated modified ultraviolet light insensitive pigment.

4. The ultraviolet light insensitive ceramic powder according to claim 3, characterized in that The ultraviolet insensitive pigments with sulfonate groups are 6-hydroxy-5-(2-methoxy-4-sulfonic acid-5-methylphenyl)azonaphthalene-2-sulfonic acid disodium salt, 1-(4'-sulfonic acid-1'-naphthazo)-2-naphthol-6,8-disulfonic acid trisodium salt, 6-hydroxy-5-[(4-sulfonic acid phenyl)azo]-2-naphthalenesulfonic acid disodium salt, 1-(4-sulfonic acid phenyl)-4-(4-sulfonic acid phenylazo)-2-naphthalenesulfonic acid disodium salt. )-5-pyrazolone-3-carboxylic acid trisodium salt, 1-acetylamino-2-hydroxy-3-(4-(4-sulfonic acid benzyl)aminophenyl)-7-sulfonic acid-1-naphthylazo)naphthalene-4,6-disulfonate, bis[4-(N-ethyl-N-3-sulfonic acid benzyl)aminophenyl]-2-sulfonic acid tolyl disodium salt, 3,3'-dioxo-2,2'-biindolyl-5,5'-disulfonic acid disodium salt or one or more thereof.

5. The ultraviolet light insensitive ceramic powder according to claim 3, characterized in that The chlorinating agent is one of thionyl chloride, chlorosulfonic acid, phosphorus oxychloride and phosphorus pentachloride; the catalyst is one of N,N-dimethylformamide, triethylamine and pyridine.

6. A method for preparing the ultraviolet light insensitive ceramic powder according to any one of claims 1 to 5, characterized in that: The specific steps are as follows: 1) dissolving a silane coupling agent in ethanol to obtain a silane coupling agent solution, then adding ceramic powder to the silane coupling agent solution to carry out a grafting reaction, and then post-treating to obtain a silane coupling agent-grafted ceramic powder; 2) dissolving the acylated UV-insensitive pigment having a sulfonate group in ethanol to obtain an acylated pigment solution, adding the silane coupling agent-grafted ceramic powder obtained in step 1) to the acylated pigment solution for a substitution reaction, and performing post-treatment after the reaction to obtain a UV-insensitive ceramic powder.

7. The method for preparing the ultraviolet light insensitive ceramic powder according to claim 6, wherein: The concentration of the silane coupling agent solution in step 1) is 5-40 wt %; the amount of ceramic powder added in step 1) is 10-70 vol % of the volume of the silane coupling agent solution; and the grafting reaction conditions in step 1) are: stirring and reacting at 10-60° C. for 4-48 hours.

8. The method for preparing the ultraviolet light insensitive ceramic powder according to claim 6, wherein: Step 2) The concentration of the acylated modified pigment solution is 0.1-20 wt %; Step 2) The amount of the silane coupling agent grafted ceramic powder added is 10-70 vol % of the volume of the acylated modified pigment solution; Step 2) The substitution reaction conditions are: reaction at 10-60° C. for 4-72 hours.

9. A high-precision ceramic photocuring slurry prepared based on the UV-insensitive ceramic powder according to any one of claims 1 to 5, characterized in that: The photoinitiator is obtained by uniformly mixing ultraviolet light insensitive ceramic powder, photosensitive resin and photoinitiator.

10. Ceramics prepared from the high-precision ceramic photocuring slurry according to claim 9.

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