Zirconium oxide paste for photocuring 3D printing and preparation method thereof

Abstract

The invention discloses zirconium oxide paste for photocuring 3D printing and a preparation method thereof. The zirconium oxide paste comprises the following raw materials in parts by weight: 72-76% of a zirconium oxide dopant; 12%-14% of a photosensitive resin premixed liquid; 1%-2% of a rheological aid; 0.8%-1.5% of a dispersing agent; 0.05%-0.1% of a defoaming agent; 0.05%-0.1% of a leveling agent; 10%-12% of a solvent; 0.3%-0.6% of a coloring agent; the invention relates to the technical field of additive manufacturing. According to the zirconium oxide paste material for photocuring 3D printing and the preparation method of the zirconium oxide paste material, a three-level grading zirconium oxide dopant is used as a main body material, under the cooperation of the photosensitive resin premixed liquid, the rheological additive, the dispersing agent, the defoaming agent, the flatting agent and the solvent, all the components are ensured to be fully dispersed, and a uniform and stable guarantee is provided for the zirconium oxide paste material in the 3D printing forming process; the surface and internal defects of a finished product are effectively eliminated, the coloring agent is used for simulating natural tooth color, and good processing performance, good mechanical performance, good biocompatibility and good aesthetic effect are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of additive manufacturing, and specifically relates to a zirconia paste for stereolithography 3D printing and a preparation method thereof. Background Art

[0002] As one of the most commonly used all-ceramic restorative materials for dentures, zirconia ceramics have good hardness and fracture toughness advantages due to their unique stress-induced phase transformation toughening mechanism. This excellent phase transformation mechanism makes zirconia ceramics stand out among many ceramic materials such as traditional glass ceramics and aluminum ceramics, and it is the all-ceramic restorative material with the highest known strength in current clinical applications. In recent years, zirconia materials have also been widely used in tooth restoration fields such as inlay repair, crown repair, and denture restoration due to their high biosecurity, stable chemical properties, excellent aesthetic effects, and high mechanical strength.

[0003] Zirconia dioxide has excellent physical and chemical properties and biocompatibility. After doping with yttrium and magnesium, it can obtain good mechanical properties and electrical properties, and is widely used in fields such as orthopedic materials, dentures, and solid electrolytes. However, due to the relatively difficult ceramic processing, its application is restricted. Especially for the processing of denture products, due to the complex surface, high surface quality, and personalized customization requirements of dentures, although the 3D printing method can conveniently obtain products that meet the target requirements, traditional zirconia materials have problems such as slow product forming speed, surface defects, and imperfect details during the stereolithography 3D printing process, and there is a large demand for post-processing of products. Therefore, a zirconia paste for stereolithography 3D printing and a preparation method thereof are specifically proposed to meet the requirements of high-efficiency and high-precision denture manufacturing and effectively improve the printing efficiency. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the present invention provides a zirconia paste for stereolithography 3D printing and a preparation method thereof, which solve the problems that traditional zirconia materials have slow product forming speed, surface defects, imperfect details, and large demand for post-processing during the stereolithography 3D printing process.

[0005] To achieve the above objectives, the present invention is realized through the following technical solutions: A zirconia paste for stereolithography 3D printing, the raw materials of which by weight include:

[0006] Zirconia dopant: 72% - 76%;

[0007] Photosensitive resin premix: 12% - 14%;

[0008] Rheology aid: 1% - 2%;

[0009] Dispersant: 0.8% - 1.5%;

[0010] Defoamer: 0.05% - 0.1%;

[0011] Leveling agent: 0.05% - 0.1%;

[0012] Solvent: 10% - 12%;

[0013] Colorant: 0.3% - 0.6%.

[0014] The present invention is further configured such that its raw materials include, by weight parts:

[0015] Zirconia dopant: 75.78%;

[0016] Photosensitive resin premix: 12%;

[0017] Rheology aid: 1%;

[0018] Dispersant: 0.8%;

[0019] Defoamer: 0.05%;

[0020] Leveling agent: 0.05%;

[0021] Solvent: 10%;

[0022] Colorant: 0.3%.

[0023] The present invention is further configured such that its raw materials include, by weight parts:

[0024] Zirconia dopant: 72%;

[0025] Photosensitive resin premix: 13.5%;

[0026] Rheology aid: 1%;

[0027] Dispersant: 0.8%;

[0028] Defoamer: 0.05%;

[0029] Leveling agent: 0.05%;

[0030] Solvent: 12%;

[0031] Colorant: 0.6%.

[0032] The present invention is further configured such that its raw materials include, by weight parts:

[0033] Zirconia dopant: 72%;

[0034] Photosensitive resin premix: 14%;

[0035] Rheology aid: 1%;

[0036] Dispersant: 1.5%;

[0037] Defoamer: 0.1%;

[0038] Leveling agent: 0.1%;

[0039] Solvent: 10.7%;

[0040] Colorant: 0.6%.

[0041] The present invention also discloses a preparation method of a zirconia paste for photocuring 3D printing, which specifically includes the following steps:

[0042] Step 1: Place the ternary-graded zirconia dopant in an oven at 120 °C and dry it for 4 h, and use ethanol to filter impurities through a 0.2-μm filter membrane;

[0043] Step 2: Add the photosensitive resin premix, rheology aid, dispersant, leveling agent, and ethanol to a stirring tank under the environmental conditions of a temperature of 25 ± 2 °C and a relative humidity < 40%, and stir at 500 rpm for 10 min;

[0044] Step 3: Add the zirconia dopant treated in Step 1, increase the rotation speed to 1000 rpm, stir for 30 min, reduce the rotation speed to 800 rpm, add the colorant, stir for 1 h, then add the defoamer, perform vacuum degassing at -0.1 MPa for 30 min, and perform centrifugal assisted degassing at a rotation speed of 3000 rpm to obtain the zirconia paste.

[0045] The present invention provides a zirconia paste for photocuring 3D printing and a preparation method thereof. It has the following beneficial effects:

[0046] (1) In the present invention, the ternary-graded zirconia dopant is used as the main material, and its strength and fracture toughness are improved by using its high strength and phase transformation toughening effect. Finally, hardness and wear resistance are provided for the finished product. With the cooperation of the photosensitive resin premix, rheology aid, dispersant, defoamer, leveling agent, and solvent, it ensures the full dispersion of each component, provides a uniform and stable guarantee for the zirconia paste during the 3D printing forming process, effectively eliminates the surface and internal defects of the finished product, and uses the colorant to simulate the natural tooth color. Each component in the formula cooperates with each other, so that the zirconia paste not only has good processing performance but also has good mechanical properties, biocompatibility, and aesthetic effects.

[0047] (2) The present invention uses a photosensitive resin premix as a photocuring carrier to ensure rapid curing and forming of the paste during 3D printing. A rheological aid is used to adjust the viscosity of the paste, enhance thixotropy, avoid collapse during printing, and reduce the need for support structures. A dispersant can prevent particle aggregation, stabilize the slurry viscosity, avoid sedimentation or stratification. In combination with an antifoaming agent and a leveling agent, it reduces bubble defects, improves the flatness between printing layers, and enhances the surface finish. The solvent is used to adjust the viscosity to control the fluidity of the paste and serves as a medium to ensure the full dispersion of each component. Detailed implementation mode

[0048] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0049] The embodiments of the present invention provide the following technical solutions:

[0050] Embodiment 1

[0051] A zirconia paste for photocuring 3D printing, the raw materials of which include by weight:

[0052] Zirconia dopant: 72%-76%;

[0053] Photosensitive resin premix: 12%-14%;

[0054] Rheological aid: 1%-2%;

[0055] Dispersant: 0.8%-1.5%;

[0056] Antifoaming agent: 0.05%-0.1%;

[0057] Leveling agent: 0.05%-0.1%;

[0058] Solvent: 10%-12%;

[0059] Colorant: 0.3%-0.6%.

[0060] Among them, the zirconia dopant is a Y-TZP powder obtained by doping 4-6 mol% of yttrium oxide powder in zirconia powder. The diameters of both the zirconia powder and the yttrium oxide powder include 1 μm, 250 nm, and 50 nm. The zirconia dopant is prepared in a three-stage grading manner, making it difficult for the resin material in the voids to accumulate, so as to improve the fluidity of the paste. At the same time, due to its greater density and better filling, the final denture product can achieve a density of 99.2%.

[0061] The photosensitive resin premix is an acrylic resin, the rheology aid is one of fumed silica and hydrogenated castor oil, the dispersant is one of ammonium polyacrylate and ammonium citrate, the defoamer is silicone, the leveling agent is an acrylate leveling agent, the solvent is ethanol and water, and the colorant is iron(III) oxide and cerium dioxide.

[0062] Example Two

[0063] On the basis of Example One, this example proposes a zirconia paste for photocuring 3D printing, and its raw materials by weight include:

[0064] Zirconia dopant: 75.78%;

[0065] Photosensitive resin premix: 12%;

[0066] Rheology aid: 1%;

[0067] Dispersant: 0.8%;

[0068] Defoamer: 0.05%;

[0069] Leveling agent: 0.05%;

[0070] Solvent: 10%;

[0071] Colorant: 0.3%.

[0072] Example Three

[0073] On the basis of Example One, this example proposes a zirconia paste for photocuring 3D printing, and its raw materials by weight include:

[0074] Zirconia dopant: 72%;

[0075] Photosensitive resin premix: 13.5%;

[0076] Rheology aid: 1%;

[0077] Dispersant: 0.8%;

[0078] Defoamer: 0.05%;

[0079] Leveling agent: 0.05%;

[0080] Solvent: 12%;

[0081] Colorant: 0.6%.

[0082] Example Four

[0083] On the basis of Example One, this example proposes a zirconia paste for photocuring 3D printing, and its raw materials by weight include:

[0084] Zirconia dopant: 72%;

[0085] Photosensitive resin premix: 14%;

[0086] Rheology aid: 1%;

[0087] Dispersant: 1.5%;

[0088] Defoamer: 0.1%;

[0089] Leveling agent: 0.1%;

[0090] Solvent: 10.7%;

[0091] Colorant: 0.6%.

[0092] The formulation components of the zirconia paste proposed in the above embodiments, and the preparation method of the zirconia paste using these formulation components specifically includes the following steps:

[0093] Step 1: Place the zirconia dopant with three - level grading in an oven at 120°C for 4 hours, and use ethanol to filter impurities through a 0.2μm filter membrane;

[0094] Step 2: Under the environmental conditions of temperature 25±2°C and relative humidity <40%, add the photosensitive resin premix, rheology aid, dispersant, leveling agent and ethanol to a stirring tank, and stir at 500 rpm for 10 minutes;

[0095] Step 3: Add the zirconia dopant treated in Step 1, increase the rotation speed to 1000 rpm, stir for 30 minutes, reduce the rotation speed to 800 rpm, add the colorant, stir for 1 hour, then add the defoamer, perform vacuum degassing at - 0.1 MPa for 30 minutes, and perform centrifugal assisted degassing at a rotation speed of 3000 rpm to obtain the zirconia paste.

[0096] According to the above preparation method, according to the specific formulation components provided in Example 2, Example 3 and Example 4, zirconia paste one, zirconia paste two and zirconia paste three are obtained respectively. Take samples of the same weight from zirconia paste one, zirconia paste two and zirconia paste three, and conduct the following simulation experiments respectively. The specific experimental steps include:

[0097] Adopt digital light processing (DLP) technology, with a printing accuracy of ±25μm, the support structure spacing is designed to be 2 - 3 mm. Inject the obtained zirconia paste sample into the material tank of a stereolithography 3D printer, set the layer thickness to 25 - 50μm, the wavelength of the ultraviolet light source is 405nm, the exposure time for each layer is 10 - 20 seconds, and the energy density is 15 - 30 mJ / cm 2, solidify layer by layer and then carry out the final debinding and sintering. In an air or nitrogen atmosphere, heat it at a heating rate of 1 - 2 °C / min to 500 - 600 °C, hold for 1 - 2 hours to remove the organic components, and then heat it at a heating rate of 5 - 10 °C / min to 1450 - 1550 °C, hold for 2 - 4 hours to obtain a dense zirconia ceramic denture.

[0098] To ensure the stability and reliability of the test results, the same samples were selected to prepare zirconia ceramic dentures with the same process at least three times. After testing, it was found that the flexural strength of the obtained dense zirconia ceramic denture was ≥ 1000 MPa, and the fracture toughness was ≥ 6 MPa·m 1 / 2 , and the density was ≥ 6.0 g / cm 3 , fully meeting the biocompatibility standard of oral repair materials.

[0099] In summary, the zirconia paste obtained by the solution proposed in the present invention effectively improves the accuracy, comfort and efficiency of denture printing in the simulation experiment of photocuring 3D printing dentures, and the biocompatibility of the obtained dentures is effectively improved.

[0100] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device.

[0101] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A zirconia paste for photocuring 3D printing, characterized in that: Its raw materials by weight include: Zirconia dopant: 72%-76%; Photosensitive resin premix: 12%-14%; Rheology aid: 1%-2%; Dispersant: 0.8%-1.5%; Defoamer: 0.05%-0.1%; Leveling agent: 0.05%-0.1%; Solvent: 10%-12%; Colorant: 0.3%-0.6%.

2. The zirconia paste for photocuring 3D printing according to claim 1, characterized in that: The zirconia dopant is a Y-TZP powder obtained by doping 4-6 mol% of yttrium oxide powder in zirconia powder, where the diameters of both the zirconia powder and the yttrium oxide powder include 1 μm, 250 nm, and 50 nm.

3. The zirconia paste for photocuring 3D printing according to claim 1, wherein: The photosensitive resin premix is an acrylic resin.

4. A zirconia paste for photocuring 3D printing according to claim 1, characterized in that: The rheology aid is one of fumed silica and hydrogenated castor oil.

5. The zirconia paste for photocuring 3D printing according to claim 1, wherein: The dispersant is one of ammonium polyacrylate and ammonium citrate.

6. The zirconia paste for photocuring 3D printing according to claim 1, characterized in that: The defoamer is silicone.

7. A zirconia paste for photocuring 3D printing according to claim 1, characterized in that: The leveling agent is an acrylate leveling agent.

8. A zirconia paste for photocuring 3D printing according to claim 1, characterized in that: The solvent is ethanol and water.

9. A zirconia paste for photocuring 3D printing and a preparation method thereof according to claim 1, characterized in that: The colorant is iron(III) oxide and cerium dioxide.

10. A preparation method of zirconia paste for photocuring 3D printing, characterized in that: Specifically, it includes the following steps: Step 1: Place the zirconia dopant in an oven at 120 °C and dry it for 4 h, and use ethanol to filter through a 0.2 μm filter membrane to remove impurities; Step 2: Under the environmental conditions of a temperature of 25±2 °C and a relative humidity <40%, add the photosensitive resin premix, rheology aid, dispersant, leveling agent, and ethanol to a stirring tank, and stir at 500 rpm for 10 min; Step 3: Add the zirconia dopant treated in Step 1, increase the rotation speed to 1000 rpm, stir for 30 min, reduce the rotation speed to 800 rpm, add the colorant, stir for 1 h, then add the defoamer, perform vacuum degassing at -0.1 MPa for 30 min, and perform centrifugal-assisted degassing at a rotation speed of 3000 rpm to obtain zirconia paste.